Neurological Disorders

Coding Dimension ID: 
303
Coding Dimension path name: 
Neurological Disorders

Induced Pluripotent Stem Cells for Tissue Regeneration

Funding Type: 
Basic Biology III
Grant Number: 
RB3-05232
ICOC Funds Committed: 
$1 341 064
Disease Focus: 
Neuropathy
Neurological Disorders
Stem Cell Use: 
iPS Cell
oldStatus: 
Active
Public Abstract: 
Induced pluripotent stem cells (iPSCs) have tremendous potential for patient-specific cell therapies, which bypasses immune rejection issues and ethical concerns for embryonic stem cells (ESCs). However, to fully harness the therapeutic potential of iPSCs, many fundamental issues of cell transplantation remain to be addressed, e.g., how iPSC-derived cells participate in tissue regeneration, which type of cells should be derived for specific therapy, and what kind of matrix is more effective for cell therapies. The goal of this project is to use iPSC-derived neural crest stem cells (NCSCs) and nerve regeneration as a model to address these fundamental issues of stem cell therapies. NCSCs are multipotent and can differentiate into cell types in all three germ layers (including neural, vascular, osteogenic and chondrogenic cells), which makes NCSC a valuable model to study stem cell differentiation and tissue regeneration. Peripheral nerve injuries and demyelinating diseases (e.g., multiple sclerosis, familial dysautonomia) affect millions of people. Stem cell therapy is a promising approach to cure these diseases, which will have broad impact on healthcare. This project will advance our understanding of how extracellular microenvironment (native or engineered) regulates stem cell fate and behavior during tissue regeneration, and whether stem cells such as iPSC-NCSCs and differentiated cells such as iPSC-Schwann cells have different therapeutic effects. The results from this project will provide insights that will facilitate the translation of stem cell technologies into therapies for nerve injuries, demyelinating diseases and many other disorders that may be treated with iPSC-NCSCs.
Statement of Benefit to California: 
Induced pluripotent stem cells (iPSCs), especially iPSCs without the integration of reprogramming factors into the genome, are valuable to model disease and to generate autologous cells for therapies. Understanding the role and differentiation of iPSC-derived cells in tissue regeneration will facilitate the translation of stem cell technologies into clinical applications. iPSC-derived neural crest stem cells (NCSCs) can differentiate into a variety of cell types, and hold promise for the therapies of diseases such as nerve injuries, demyelinating diseases, spina bifida, vascular diseases, osteoporosis and arthritis. The isolation and characterization of iPSC-NCSCs will provide a basis for their broad applications in tissue regeneration and disease modeling. This project will use peripheral nerve regeneration as a model to address the fundamental issues of using iPSC-NCSCs for therapies. Peripheral nerve injuries (over 800,000 cases in the United States every year) are very common following traumatic injuries and major surgeries (e.g., removing tumor), which often require surgical repair. Stem cell therapies can accelerate nerve regeneration and avoid the degeneration of muscle and other tissues lack of innervation. Since iPSC-NCSCs can promote the myelination of axons, the therapies for nerve injuries could also be adopted to treat demyelinating diseases. In many cases of stem cell therapies, matrix and scaffold materials are needed to enhance cell survival and achieve local delivery. The studies on appropriate matrix for stem cell delivery will provide a rational basis for designing and optimizing materials for stem cell therapies. The fundamental issues addressed in this project, such as the differentiation and signaling of transplanted cells, the therapeutic effects of cells at the different stages of differentiation and the roles of delivery matrix/materials, will have implications for stem cell therapies in many other tissues. Overall, the results from this project will advance our knowledge on stem cell differentiation and function during tissue regeneration, help us translate the knowledge into clinical applications, and benefit the health care in California and our society.
Progress Report: 
  • Induced pluripotent stem cells (iPSCs) have tremendous potential for regenerative medicine applications. Here we use peripheral nerve regeneration as a model to address the fundamental issues of using iPSCs and their derivatives for therapies. Specifically, we used integration-free iPSCs for our studies because this type of iPSCs has potential for clinical applications. We derived and characterized neural crest stem cells (NCSCs) from integration-free iPSCs, and demonstrated that these NCSCs can differentiate into a variety of cell types, including Schwann cells. We delivered NCSCs into nerve conduits to treat peripheral nerve injuries, and performed functional studies, electrophysiology analysis and histological analysis. Ongoing studies suggest that the transplantation of iPSC-NCSCs accelerate nerve regeneration. To investigate the interactions of transplanted stem cells with endogenous neural progenitors, we isolated and characterized endogenous progenitors from injured nerves, which will be used for mechanistic studies. In addition, we engineered the chemical components and the structure of nerve conduits, and developed and characterized hydrogels that could be used to deliver neurotrophic factors and minimize scar formation. The roles of neurotrophic factors, transplanted/endogenous stem cells and matrix for stem cell delivery will be investigated.
  • We use peripheral nerve regeneration as a model to address the critical issues of using induced pluripotent stem cells (iPSCs) and their derivatives for tissue regeneration. In the past year, we have made progress in all three Specific Aims. We generated 5 new integration-free IPSC lines by using episomal reprogramming. We also tested the methods of using biomaterials and chemical compounds to reprogram cells, in the presence or absence of transcriptional factors. We have derived and characterized additional neural crest stem cell (NCSC) lines from these new iPSC lines, and demonstrated that these NCSCs are multipotent in their differentiation potential. To investigate the mechanisms of how NCSCs enhanced the functional recovery of transected sciatic nerves, we examined the effects of paracrine signaling, cell differentiation and matrix stiffness. In vivo experiments showed that transplanted cells secreted neurotrophic factors to promote axon regeneration. In addition, NCSCs differentiated into Schwann cells to enhance myelination. The stiffness of extracellular matrix (ECM) indeed has effect on NCSC differentiation.

Use of human iPS cells to study spinal muscular atrophy

Funding Type: 
Basic Biology III
Grant Number: 
RB3-02161
ICOC Funds Committed: 
$1 268 868
Disease Focus: 
Spinal Muscular Atrophy
Neurological Disorders
Pediatrics
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Active
Public Abstract: 
Spinal muscular atrophy (SMA) is one of the most common autosomal recessive disorders that cause infant mortality. SMA is caused by loss of the Survival of Motor Neuron (SMN) protein, resulting in motor neuron (MN) degeneration in the spinal cord. Although SMN protein plays diverse roles in RNA metabolism and is expressed in all cells, it is unclear why a deficiency in SMN only causes MN degeneration. Since patient samples are rarely available, most knowledge in SMA is gained from animal model studies. While these studies have provided important information concerning the cause and mechanism of SMA, they are limited by complicated genetic manipulation. Results from different models are also not always consistent. These problems can be resolved if SMA patient’s MNs become readily available. Recent progress in the generation of induced pluripotent stem (iPS) cells from differentiated adult cells provides an opportunity to establish human cell-based models for neurodegenerative diseases. These cells, due to their self-renewal property, can provide an unlimited supply of the affected cell type for disease study in vitro. In this regard, SMA iPS cells may represent an ideal candidate for disease modeling as SMA is an early onset monogenic disease: the likelihood to generate disease-specific phenotypes is therefore higher than iPS cells derived from a late onset disease. In addition, the affected cell type, namely MNs, can readily be generated from iPS cells for the study. For these reasons, we established several SMA iPS cell lines from a type 1 patient and showed specific deficits in MNs derived from these iPS cells. Whether MNs derived from these iPS cell lines can recapitulate a whole spectrum of SMA pathology in animals and patients remains unclear. An answer to this question can ensure the suitability of using the iPS cell approach to study SMA pathogenesis in cell culture. We propose to examine cellular and functional deficits in MNs derived from these SMA iPS cells in Aim 1. The availability of these iPS cells also provides an opportunity to explore the mechanisms of selective MN degeneration in SMA. Dysregulation of some cellular genes has been implicated in SMA pathogenesis. We propose to use these iPS cell lines to address how one such gene is affected by SMN deficiency (Aim 2) and how a deficit in these genes leads to selective MN degeneration (Aim 3). Our study should provide valuable insights in the understanding of SMA pathogenesis and aid in exploring new molecular targets for drug intervention.
Statement of Benefit to California: 
Spinal muscular atrophy (SMA) is one of the most common autosomal recessive disorders in humans and the most common genetic cause of infant mortality. SMA is caused by loss of the Survival of Motor Neuron (SMN) protein, resulting in motor neuron (MN) degeneration in the spinal cord. SMA has a carrier frequency of approximately 1 in 35 and an incidence of 1 in 6000 in human population. In severe SMA cases, the disease onset initiates before 6 months of age and death within the first 2 years of life. Currently, there is no cure for SMA. Since MN samples from patients are rarely available, most knowledge in SMA is gained from animal model studies. While these studies have provided important information concerning the cause and mechanism of SMA, they are limited by complicated genetic manipulation. Results from different models are not always consistent either. Large-scale drug screening to treat SMA is also hampered by the lack of suitable cell lines for the study. These problems can potentially be resolved if SMA patient’s MNs become readily available. Our effort to derive induced pluripotent stem (iPS) cells from a SMA patient provides an unlimited supply of SMA cells to carry out studies to explore the disease mechanism in vitro. A better understanding in the disease mechanisms would benefit California by the identification of potential cellular targets for drug treatment. The knowledge gained from our study can also facilitate the use of these iPS cells as a platform for large-scale drug screening and validation. Our study should provide valuable insights in the understanding of SMA pathogenesis and aid in exploring new molecular targets for drug intervention.
Progress Report: 
  • During the past fiscal year, we have established in vitro coculture between motoneurons and myocytes. This coculture system will form the basis for the analysis of potential SMA pathogenesis induced by the motoneurons derived from SMA iPS cells. We have also started the analysis of potential cellular targets whose activity is affected by SMN deficiency.
  • Spinal muscular atrophy (SMA) is one of the most common autosomal recessive disorders that cause infant mortality. SMA is caused by loss of the Survival of Motor Neuron (SMN) protein, resulting in motor neuron (MN) degeneration in the spinal cord. Although SMN protein plays diverse roles in RNA metabolism and is expressed in all cells, it is unclear why a deficiency in SMN only causes MN degeneration. Since patient samples are rarely available, most knowledge in SMA is gained from animal model studies. While these studies have provided important insights of the cause and mechanism of SMA, they are limited by complicated genetic manipulation. Results from different models are also not always consistent. These problems can be addressed using induced pluripotent stem cells (iPSCs) derived from patient’s fibroblasts. These cells, due to their self-renewal capacity and their ability to differentiate into neuronal cells, can in theory provide an unlimited supply of the affected MNs for SMA study. We propose to examine cellular and functional deficits in MNs derived from these SMA iPS cells in Aim 1. To increase the yield of MN production, we have tested new strategies to differentiate SMA iPSCs into MNs. The improvement makes it feasible to isolate more pure populations of MNs for the study of SMA pathogenesis in vitro. The availability of these iPSC lines also provides an opportunity to explore the mechanisms of selective MN degeneration in SMA. Dysregulation of some cellular genes has been implicated in SMA pathogenesis. We continue to study the role of one particular cellular gene whose expression is reduced in SMA (Aim 2). We are taking approaches to reveal how SMN deficiency causes this change in gene expression. We are also taking a genomic approach to reveal all the affected genes and the signaling pathways in SMA MNs and understand how a deficit in these genes leads to selective MN degeneration (Aim 3). Our study should provide valuable insights in the understanding of SMA pathogenesis and aid in exploring new molecular targets for drug intervention.

Generation and characterization of corticospinal neurons from human embryonic stem cells

Funding Type: 
Basic Biology III
Grant Number: 
RB3-02143
ICOC Funds Committed: 
$1 355 063
Disease Focus: 
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Active
Public Abstract: 
A major goal of stem cell research is to generate various functional human cell types that can be used to better understand how these cells work and to use them directly in therapies. There are currently no effective treatments, let alone a cure, for many neurological conditions. Two particular devastating neurological conditions, spinal cord injury and amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease) share a common element. That is, in both conditions, the corticospinal motor neurons that control skilled voluntary movement are severely damaged, leading to significant loss of motor control. There has been extensive research on spinal cord injury and ALS in recent years. In the field of spinal cord injury, much effort has been devoted to repairing the damaged nerve paths, but this has turned out to be extremely challenging. The work on ALS, on the other hand, has mostly focused on the spinal motor neurons (often referred to as the lower motor neurons in the context of ALS). Our proposed study focuses on the corticospinal motor neurons (or the upper motor neurons) and, more broadly, the subcerebral projection neurons. Taking clues from studies in mice, we aim to understand how the subcerebral projection neurons including the corticospinal motor neurons can be made from human embryonic stem cells. We will focus on the later steps in differentiation that are not well understood, which gave rise to different types of neurons in the cerebral cortex. To aid in this process, we have engineered a fluorescent reporter in human embryonic stem cells, which, when the stem cells are turned into corticospinal motor neurons and related subcerebral projection neurons, will light up – literally. We will probe the molecular control of this process and determine if corticospinal motor neurons made in a culture dish, when introduced back into an organism, can send projections to the spinal cord, as they would normally do during development. Most of our knowledge about the development of corticospinal motor neurons comes from studies with mouse models. As there are likely to be important differences between humans and mice, we will pay special attention to the similarities and differences between mouse and human corticospinal motor neurons. Knowledge gained from this study will pave the way to make better disease-models-in-a-dish for neurological conditions such as ALS and to develop therapies for ALS, spinal cord injury, traumatic brain injury, stroke and other neurological conditions when corticospinal motor neurons are damaged.
Statement of Benefit to California: 
Neurological conditions affect millions of Californians each year. Spinal cord injury is one particularly debilitating neurological condition. The disability, loss of earning power, and loss of personal freedom associated with spinal cord injury is devastating for the injured individual, and creates a financial burden of an estimated $400 million annually for the state of California. Research is the only solution as currently there is no cure for spinal cord injury. A major functional deficit for patients of spinal cord injury is the loss of motor control. Corticospinal motor neurons mediate skilled, voluntary movement in humans and damage to these neurons leads to severe disability. Our proposed study focuses on the understanding of how corticospinal motor neurons and, more broadly, subcerebral projection neurons can be made from human embryonic stem cells under culture conditions, and how they can be introduced back to central nervous system. Understanding this process will allow scientists to design ways to use these cells for transplantation therapies not only for spinal cord injury, but also for other neurological conditions such as amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease). Effective treatments promoting functional repair will significantly increase personal independence for people with spinal cord injury and decrease the financial burden for the State of California. More importantly, treatments that enhance functional recovery will improve the quality of life for those who are directly or indirectly affected by spinal cord injury, ALS and other neurological conditions.
Progress Report: 
  • A major goal of stem cell research is to generate various functional human cell types to promote repair or replacement in injury or disease. Our lab studies the repair of central nervous system after injury such as a spinal cord injury. We have been utilizing a fluorescent reporter line we developed with CIRM funding to enrich and characterize human corticospinal motor neurons, a neuronal population that is damaged or lost in spinal cord injury and amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease). These neurons control skilled voluntary movement in humans, the loss or damage of which leads to paralysis and disability. We have made significant progress in this funding period. We validated that our fluorescent reporter works as intended. We found that reporter gene expression represents cells of different developmental stages at different times of differentiation. We have done the first batches of transplantation studies to show that it is possible to use the reporter gene to track the cells and cellular processes in the host central nervous system. In addition, we have developed a separate reporter gene to universally mark all embryonic stem-derived cells, a tool that may be useful to other stem cell researchers. We are now ready to move to the next phase of the project: to characterize corticospinal motor neurons in more detail in vitro and in vivo. Knowledge gained from this study will pave the way to make better disease-models-in-a-dish for neurological conditions such as ALS and to develop therapies for ALS, spinal cord injury, traumatic brain injury, stroke and other neurological conditions when corticospinal motor neurons are damaged of lost.
  • A major goal of stem cell research is to generate various functional human cell types to promote repair or replacement in injury or disease. Our lab studies the repair of central nervous system after injury such as a spinal cord injury. We have been utilizing a fluorescent reporter line we developed with CIRM funding to derive and characterize human corticospinal motor neurons, a neuronal population that is damaged or lost in spinal cord injury and amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease). These neurons are of paramount importance to skilled voluntary movement in humans, the loss or damage of which leads to paralysis and disability. The goal for making a reporter line is that whenever the cells light up (literally), we will know what they have become the type of cells that we would wish to get. Following last year’s initial progress, we have made significant progress in this funding period. We found that our fluorescent reporter is useful in following the desired cell types throughout cell growth in culture dishes or after we introduce these cells into animal models by transplantation. We have performed experiments to validate the identity and usefulness of these cells. In culture, these cells exhibit the desired signature gene expression pattern, electrophysiological properties and morphologies as well. We will continue to improve our culture condition to maximize efficiency and purity. Meanwhile, we have transplanted these cells into the mouse brain to study them in the complex central nervous system because many of the properties cannot be studied in cell culture such as the connection of nerve cells to other brain area or spinal cord. We were excited to find that these cells, once transplanted, can survive, integrate into the mouse central nervous system, and send out long neuronal processes characteristic of endogenous nerve cells. Some of the projections appear to take the path of the projections of the corticospinal motor neurons, indicating that our approach will likely succeed. Thanks to CIRM’s support, we will continue to investigate the various parameters to improve our transplantation studies. Knowledge gained from this study will pave the way to make better disease-models-in-a-dish for neurological conditions such as ALS and to develop therapies for ALS, spinal cord injury, traumatic brain injury, stroke and other neurological conditions when corticospinal motor neurons are damaged of lost.

Viral-host interactions affecting neural differentiation of human progenitors

Funding Type: 
Basic Biology III
Grant Number: 
RB3-05219
ICOC Funds Committed: 
$1 372 660
Disease Focus: 
Infectious Disease
Neurological Disorders
Pediatrics
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 
Human cytomegalovirus (HCMV) is the major cause of birth defects, almost all of which are neuronal in origin. Approximately 1% of newborns are infected, and of the 13% that are symptomatic at birth, 50% will have severe permanent hearing deficits, vision loss, motor impairment, and mental retardation. At least 14% of asymptomatic infants also will later show disabilities. Much of this effect is likely caused by HCMV affecting neural development in the fetus. Embryonic stem cells are an excellent source of human progenitors, which are cells that can turn into mature neurons i.e. neural differentiation. We know from published cell culture studies that HCMV affects neural progenitor cells during neural differentiation, but it is unclear as to what are the underlying molecular mechanisms for its effect. A major goal of our research is to understand at a high-resolution how HCMV controls the way neural progenitors become proper neurons. Elucidation of the genes that are affected will serve as a basis for therapeutic strategies to ameliorate the effects of HCMV infection in newborns. The significance of our studies also extends to the serious problem of HCMV infection in immunocompromised individuals, with recipients of allogeneic transplants having a high risk of severe disease and allograft rejection. This potential problem in stem cell therapy has received little attention thus far. The proposed use of stem cell transplantation in treating neuronal injury and neurodegenerative diseases, as well as transplantation of other organ-specific precursors, makes it imperative to understand how disseminated HCMV infection in immunosuppressed recipients will affect the function and differentiation of the cells.
Statement of Benefit to California: 
Human cytomegalovirus (HCMV) is the major viral cause of birth defects. In 2009, there were 526,774 births in California, resulting in congenital HCMV infection in approximately 5,200 newborns, with at least 800 infants expected to have long-lasting disabilities. Congenital cytomegalovirus infection is the most common nongenetic congenital cause of deafness. In contrast, before the development of the rubella vaccine, less than 70 infants per year in the entire US were reported to have congenital rubella syndrome, also associated with deafness. The burden to families and the economic costs to society of congenital cytomegalovirus infection are immense, and there is no vaccine available. Our proposed research serves to form the basis of future therapies to ameliorate, or even reduce this medical burden. The significance of our studies also extends to the serious problem of HCMV infection in immunocompromised individuals who receive transplants of organs and stem cells from other individuals. Infection in these transplant recipients often results in severe disease and rejection of the transplant. The California Institute for Regenerative Medicine has made a major commitment to provide funding to move stem cell-based therapies to clinical trials. The goal of using stem cell transplantation to treat neuronal injury and neurodegenerative diseases, as well as transplantation of other organ-specific precursors, makes it imperative to understand how disseminated HCMV infection in immunosuppressed recipients will affect the function and differentiation of the cells. Our research will provide the knowledge base to understand the genes that are changed during HCMV infection of human neural progenitors and neurons. It will also provide a foundation for studies of how other viruses will affect human neurons, and likely, other cell-types. Intellectual property from this work will feed into opportunities for antiviral strategies and increased jobs in biotech for Californians.
Progress Report: 
  • Congenital human cytomegalovirus (HCMV) infection is a major cause of central nervous system structural anomalies and sensory impairments in the newborn. It is likely that the timing of infection as well as the range of susceptible cells at the time of infection will affect the severity of the disease. A major goal of our research is to understand at a high-resolution the effects of HCMV infection on the neural lineage specification and maturation of stem and progenitor cells. Elucidation of the genes and cellular processes that are affected will serve as a basis for therapeutic strategies to ameliorate the effects of HCMV infection in newborns. The significance of our studies also extends to the serious problem of HCMV infection in immunocompromised individuals, with recipients of allogeneic transplants having a high risk of severe disease and allograft rejection. This potential problem in stem cell therapy has received little attention thus far. The proposed use of stem cell transplantation in treating neuronal injury and neurodegenerative diseases, as well as transplantation of other organ-specific precursors, makes it imperative to understand how disseminated HCMV infection in immunosuppressed recipients will affect the function and differentiation of the cells.
  • This past year, we have made significant progress in accomplishing the goals of this project. We used human embryonic stem cells-derived primitive pre-rosette neural stem cells (pNSCs) maintained in chemically defined conditions to study host-HCMV interactions in early neural development. Infection of pNSCs with HCMV was largely inefficient and non-progressive. At low multiplicity of infection (MOI), we observed severe defects with regards to the proportion of cells expressing the major immediate-early proteins (IE) despite an optimal viral entry, thus indicating the existence of a blockade to specific pre-IE events. IE expression, even at high MOI, was found to be restricted to a subset of cells negative for the expression of the forebrain marker FORSE-1. Treatment of pNSCs with the caudalizing agent retinoic acid rescued IE expression, suggesting that the hindbrain microenvironment might be more permissive for the infection. Transactivation of the viral early genes was found to be severely debilitated and expression of the late genes was barely detectable even at high MOI. Differentiation of pNSCs into primitive neural progenitor cells (pNPCs) restored IE expression but not the transactivation of early and late genes. Increasing the number of viral particles bypassed this barrier to early gene expression and thus permitted expression of the late genes in pNPCs. Consequently, viral spread was only observed at high MOI but was largely restricted to one cycle of replication as secondarily infected cells failed to efficiently express early genes. Of note, virions produced in pNPCs and pNSCs were exclusively cell-associated. Finally, we found that viral genomes could persist in pNSCs culture up to a month after infection despite the absence of detectable IE expression by immunofluorescence. Clonogenic expansion of infected pNSCs revealed that the presence of viral DNA and IE proteins were insufficient to block host cell division therefore allowing the survival of viral genomes via cellular division rather than viral replication. These results highlight the complex array of hurdles that HCMV must overcome in order to infect primitive neural stem cells and suggest that these cells might act as a reservoir for the virus. To study in greater depth the molecular basis of the interaction of HCMV with cell of the neural lineage, we also have initiated high-throughput genomics approaches to analyze HCMV microRNAs, alterations in cellular microRNA and gene expression profiles, and global defects in host alternative splicing in infected and uninfected pNSC-derived NPCs. Interestingly, although there are many changes in host cell gene expression in the infected cells, there was only a small overlap with the set of changes we had found in infected human fibroblasts. This highlights the importance of performing these studies in the relevant targets of the virus in the developing fetus.
  • We expect that the results of these studies will provide an unprecedented resolution of the effects on neurogenesis when HCMV infects a newborn, serve as a foundation for future therapeutic efforts in preventing the birth defects due to HCMV, and provide insight into the serious potential problem of disseminated HCMV in immunosuppressed individuals receiving transplanted allogeneic stem cells.
  • Congenital human cytomegalovirus (HCMV) infection is a major cause of central nervous system structural anomalies and sensory impairments in the newborn. A major goal of our research is to understand at a high-resolution the effects of HCMV infection on the neural lineage specification and maturation of stem and progenitor cells. Elucidation of the genes and cellular processes that are affected will serve as a basis for therapeutic strategies to ameliorate the effects of HCMV infection in newborns. The significance of our studies also extends to the serious problem of HCMV infection in immunocompromised individuals, with recipients of allogeneic transplants having a high risk of severe disease and allograft rejection. This potential problem in stem cell therapy has received little attention thus far. The proposed use of stem cell transplantation in treating neuronal injury and neurodegenerative diseases, as well as transplantation of other organ-specific precursors, makes it imperative to understand how disseminated HCMV infection in immunosuppressed recipients will affect the function and differentiation of the cells.
  • This past year, we have made significant progress in accomplishing the goals of this project. We used human embryonic stem cell (hESC)-derived primitive pre-rosette neural stem cells (pNSCs) to study host-HCMV interactions in early neural development and found with several different lines of hESC-derived pNSCs that HCMV infection is inefficient and non-progressive. Differentiation of pNSCs into primitive neural progenitor cells (pNPCs) restored some viral early gene expression but not the transactivation of late genes. Impaired viral gene expression in pNSCs was not a result of inefficient viral entry or nuclear import of viral DNA but correlated with deficient nuclear import of the virion-associated protein UL82, which is believed to play a role in removing barriers to viral RNA synthesis. Additionally, we found that viral genomes could persist in pNSCs culture up to a month after infection despite the absence of detectable viral lytic gene expression, although we could also detect expression of viral latency-associated genes, suggesting that the virus becomes latent in pNSCs.
  • To study in greater depth the molecular basis of the interaction of HCMV with cells of the neural lineage, we have continued high-throughput genomics approaches to analyze HCMV microRNAs, alterations in cellular microRNA and gene expression profiles, and global defects in host alternative splicing in infected and uninfected pNSC-derived NPCs. We found that in infected NPCs, there was specific downregulation of transcripts related to neuron differentiation. These findings demonstrate the capacity of HCMV infection to alter the neural identities of key precursor cells in the developing nervous system. We also analyzed our infected NPC RNA-seq database for differences in host mRNA polyadenylation patterns and found that over a hundred transcripts were significantly altered in terms of their 3' end cleavage site preference, with the majority of these events resulting in shortened 3' UTRs.
  • Our finding that HCMV induces major changes in the transcriptome of NPCs, particularly at the level of neural genes, suggested that the virus might affect these cells functionally. To directly evaluate this, we differentiated pNSCs into midbrain dopaminergic (mDA) neurons and infected these cells at different times of the differentiation process. Seeding pNSCs in differentiation medium for 6 weeks yields a high frequency of mature neurons with long axonal projections. Infection of pNSCs at the start of differentiation greatly reduces generation of beta III-tubulin+ neurons 4 weeks later, and prevents differentiation to mature MAP2+ neurons. Infection after 1 week of differentiation also reduces the number of beta III-tubulin+ neurons and results in massive cell death. Infection at 2 weeks after differentiation start does not reduce the number of βIII-tubulin+ or MAP2+ neurons, but the cells display major anomalies. Since neurons are highly sensitive to oxidative stresses and HCMV infection increases the production of reactive oxygen species in fibroblasts, we investigated whether the same effect occurred in neuronal cultures. When pNSCs were infected at week 4 after differentiation, high levels of ROS were detected. These results suggest that the complex effects of HCMV infection at various stages of neural cell differentiation on both cell survival and maturation may account for the broad range of birth defects.
  • We expect that the results of these studies will provide an unprecedented resolution of the effects on neurogenesis when HCMV infects a newborn, serve as a foundation for future therapeutic efforts in preventing the birth defects due to HCMV, and provide insight into the serious potential problem of disseminated HCMV in immunosuppressed individuals receiving transplanted allogeneic stem cells.

Studying neurotransmission of normal and diseased human ES cell-derived neurons in vivo

Funding Type: 
Basic Biology III
Grant Number: 
RB3-02129
ICOC Funds Committed: 
$1 382 400
Disease Focus: 
Autism
Neurological Disorders
Rett's Syndrome
Pediatrics
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 
Stem cells, including human embryonic stem cells, provide extraordinary new opportunities to model human diseases and may serve as platforms for drug screening and validation. Especially with the ever-improving effective and safe methodologies to produce genetically identical human induced pluripotent stem cells (iPSCs), increasing number of patient-specific iPSCs will be generated, which will enormously facilitate the disease modeling process. Also given the advancement in human genetics in defining human genetic mutations for various disorders, it is becoming possible that one can quickly start with discovery of disease-related genetic mutations to produce patient-specific iPSCs, which can then be differentiated into the right cell type to model for the disease in vitro, followed by setting up the drug screening paradigms using such disease highly relevant cells. In the context of neurological disorders, both synaptic transmission and gene expression can be combined for phenotyping and phenotypic reversal screening and in vitro functional (synaptic transmission) reversal validation. The missing gap for starting with the genetic mutation to pave the way to drug discovery and development is in vivo validation-related preclinical studies. In order to fill this gap, in this application we are proposing to use Rett syndrome as a proof of principle, to establish human cell xenografting paradigm and perform optogenetics and in vivo recording or functional MRI (fMRI), to study the neurotransmission/connectivity characteristics of normal and diseased human neurons. Our approach will be applicable to many other human neurological disease models and will allow for a combination of pharmacokinetic, and in vivo toxicology work together with the in vivo disease phenotypic reversal studies, bridging the gap between cell culture based disease modeling and drug screening to in vivo validation of drug candidates to complete the cycle of preclinical studies, paving the way to clinical trials. A success of this proposed study will have enormous implications to complete the path of using human pluripotent stem cells to build novel paradigms for a complete drug development process.
Statement of Benefit to California: 
Rett Syndrome (RTT) is a progressive neurodevelopmental disorder caused by primarily loss-of-function mutations in the X-linked MeCP2 gene. It mainly affects females with an incidence of about 1 in 10,000 births. After up to 18 months of apparently normal development, children with RTT develop severe neurological symptoms including motor defects, mental retardation, autistic traits, seizures and anxiety. RTT is one of the Autism Spectrum Disorders (ASDs) that affects many children in California. In this application, we propose to use our hESC-based Rett syndrome (RTT) model as a proof-of-principle case to define a set of core transcriptome that can be used for drug screenings. Human embryonic stem cells (hESCs) hold great potential for cell replacement therapy where cells are lost due to disease or injury. For the diseases of the central nervous system, hESC-derived neurons could be used for repair. This approach requires careful characterization of hESCs prior to utilizing their therapeutic potentials. Unfortunately, most of the characterization of hESCs are performed in vitro when disease models are generated using hESC-derived neurons. In this application, using RTT as a proof of principle study, we will bridge the gap and perform in vivo characterization of transplanted normal and RTT human neurons. Our findings will not only benefit RTT and other ASD patients, but also subsequently enable broad applications of this approach in drug discovery using human pluripotent stem cell-based disease models to benefit the citizens of California in a broader spectrum.
Progress Report: 
  • The potential of stem cells, such as human embryonic stem cells and induced pluripotent stem cells (iPSCs), has been widely recognized for cell replacement therapy, modeling human diseases and serving as a platform for drug screening and validation. In this grant, we proposed to use Rett syndrome as a proof of principle, to establish a human cell xenografting paradigm (i.e., transplanting human cells into mouse/rat embryos) and perform in vivo analyses to study the neurotransmission characteristics of normal and diseased human neurons. We initially determined that it was feasible to use the lentiviral CamKII-ChR2 construct to drive excitatory neuronal-specific expression of ChR2 in mouse hippocampal pyramidal neurons as well as human embryonic stem cell derived neurons. Importantly, we have found that both ChR2 expressing mouse hippocampal neurons and human neurons derived from embryonic stem cells can spike action potentials when stimulated in vitro, indicating that exogenously expressed ChR2 is functional. Furthermore, we successfully transplanted human embryonic stem cell derived neural stem/progenitor cells into fetal rat forebrain at embryonic day 17. Our analysis of the recipient animals at postnatal day 21 showed that approximately 40-50% of the cells survived and began to express neuronal markers, such as NeuN, indicating the neuronal differentiation, as well as the long-term survival, of transplanted human cells in the recipient animals. As originally proposed, we will proceed with the documentation of the in vivo phenotype of Rett syndrome diseased neurons. Our approach will be particularly crucial to not only validate candidate drugs or other therapeutic interventions to treat Rett syndrome using xeno-transplanted human Rett neurons, but also to study the in vivo behavior of those neurons with and without the therapeutic intervention.
  • Stem cells, such as human embryonic stem cells and induced pluripotent stem cells (iPSCs), carry great potentials for cell replacement therapy, human diseases modeling and drug screenings. We proposed to use Rett syndrome (RTT) as a proof of principle, to establish a human cell xenografting paradigm (i.e., transplanting human cells into mouse/rat brains) to study the function of normal and diseased human neurons in vivo. During the 2nd year of funding, we gained new insights into the electrophysiological characteristics of RTT neurons. Specifically, we found that the neurotransmission phenotype of neurons derived from RTT patient-specific iPSCs was highly circuitry-dependent. On the other hand, when cell-intrinsic electrophysiological properties were measured, extremely stable abnormalities in action potential profiles, resting membrane potentials, etc. were observed, indicative of the validity of the culture system. Given that currently scientists have very limited control over the features of neuronal connections formed in culture conditions, our findings make the in vivo assessment of RTT neuronal properties even more desirable, because the circuitry features are more amenable in vivo, with anatomical cues. In light of aforementioned in vitro findings, we focused our attention to both cell-intrinsic electrophysiological characteristics of RTT neurons, as well as their connectivity or neural network properties, after neurons were integrated into host circuits in vivo following xenotransplantation. Our preliminary data demonstrated that the action-potential abnormalities of RTT neurons are preserved in vivo after xenotransplantation. So far we have established a relatively optimized system for studying human iPSC-derived RTT neurons integrated into mouse brains. We are poised to uncover not only the neuronal intrinsic electrophysiological properties but also the connectivity of wild type and RTT neurons with host circuits. Moreover, we have made substantial progress with regards to a novel technology, i.e., single neuron gene expression profiling coupled with electrophysiological recordings both in vitro and in vivo. Up to now, 8 RTT iPSC-derived neurons were profiled via RNA sequencing following electrophysiological recordings, and some interesting clues have already been revealed. Currently we are collecting more neurons and we expect to make unprecedented discoveries with mechanistic insights into RTT disease pathophysiology, which will facilitate the development of novel therapies for RTT. This paradigm is also generally applicable for studying other neurological disorders.
  • Over the last decade, the importance of the stem cells for cell replacement therapy, human disease modeling and drug toxicity/therapy screenings has been greatly appreciated by both the general public and the scientific community. In our application utilizing human embryonic stem cells and induced pluripotent stem cells (iPSCs), we proposed to use Rett syndrome (RTT) as a proof of principle to establish a human cell xenografting paradigm (i.e., transplanting human cells into mouse/rat brains) to study the function of normal and diseased human neurons in vivo. While we increased our knowledge about the electrophysiological characteristics of RTT neurons during Year 2 funding, we mainly focused on the transplantation of the normal and diseased cells, as well as the molecular signatures of transplanted cells at a single cell level, during Year 3 of the funding period. Following our initial transplantation experiments, we observed clustering of the transplanted cells at the injection site, even though there were number of cells integrating into the host brains. In order to circumvent this problem and answer our original questions, we developed an alternative approach. Specifically, we adopted the “transparent brain” methodology to better visualize the integration and the projections of the transplanted cells, as well as the circuitries that they participate, in the host environment to reveal the connectivity of wild type and RTT neurons with the host circuits. With this method, we’re able to follow the transplanted RTT neurons at a higher resolution -without the limitations of the conventional approaches- for studying human iPSC-derived RTT neurons integrated into mouse brains. As part of our last Specific Aim, we’ve performed single neuron gene expression profiling coupled with electrophysiological recordings both in vitro and in vivo. Specifically, we implemented electrophysiological recordings from the transplanted RTT iPSC-derived neurons and isolated the genomic material from the same cell to perform transcriptome analyses. We collected significant amount of data from RNA sequencing experiments and have been performing relevant bioinformatic analyses. In order to complete the gene expression profiling analysis, we obtained a no-cost-extension of the project, and upon completion of the no-cost-extension period, the relevant report will be filed outlining the outcomes of the single neuron transcriptome analysis coupled with electrophysiology. Collectively, our findings provide mechanistic insights into RTT disease pathophysiology, which will facilitate the development of novel therapies for RTT. Lastly, our approach is applicable for studying other neurological disorders in addition to RTT.

Developmental Candidates for Cell-Based Therapies for Parkinson's Disease (PD)

Funding Type: 
Early Translational I
Grant Number: 
TR1-01267
ICOC Funds Committed: 
$5 416 003
Disease Focus: 
Parkinson's Disease
Neurological Disorders
Collaborative Funder: 
Victoria, Australia
Stem Cell Use: 
Adult Stem Cell
Embryonic Stem Cell
iPS Cell
oldStatus: 
Active
Public Abstract: 
Parkinson's Disease (PD) is a devastating disorder, stealing vitality from vibrant, productive adults & draining our health care dollars. It is also an excellent model for studying other neurodegenerative conditions. We have discovered that human neural stem cells (hNSCs) may exert a significant beneficial impact in the most authentic, representative, & predictive animal model of actual human PD. Interestingly, we have learned that, while some of the hNSCs differentiate into replacement dopamine (DA) neurons, much of the therapeutic benefit derived from a stem cell action we discovered a called the “Chaperone Effect” – even hNSC-derived cells that do not become DA neurons contributed to the reversal of severe Parkinsonian symptoms by protecting endangered host DA neurons & their connections, restoring equipoise to the host nigrostriatal system, and reducing pathological hallmark of PD. While the ultimate goal may someday be to replace dead DA neurons, the Chaperone Effect represents a more tractable near-term method of using cells to address this serious condition. However, many questions remain in the process of developing these cellular therapeutic candidates. A major question is what is the best (safest, most efficacious) way to generate hNSCs? Directly from the fetal brain? From human embryonic stem cells? From skin cells reprogrammed to act like stem cells? Also, would benefits be even greater if, in addition to harnessing the Chaperone Effect, the number of stem cell-derived DA neurons was also increased? And could choosing the right stem cell type &/or providing the right supportive molecules help achieve this? This study seeks to answer these questions. Importantly, we will do so using the most representative model of human PD, a model that not only mimics all of the human symptomatology but also all the side-effects of treatment; inattention to this latter aspect plagued earlier clinical trials in PD. A successful therapy for PD would not only be of great benefit for the many patients who now suffer from the disease, or who are likely to develop it as they age, but the results will help with other potential disease applications due to greater understanding of stem cell biology (particularly the Chaperone Effect, which represents “low hanging fruit”) as well as their potential complications and side effects.
Statement of Benefit to California: 
Not only is Parkinson's Disease (PD) a devastating disease in its own right-- impairing typically vibrant productive adults & draining our health care dollars -- but it is also an excellent model for studying other neurodegenerative diseases. We have discovered that stem cells may actually exert a beneficial impact independent of dopamine neuron replacement. As a result of a multiyear study performed by our team, implanting human neural stem cells (hNSCs) into the most authentic, representative, and predictive animal model of actual human PD, we learned that the cells could reverse severe Parkinsonian symptoms by protecting endangered host dopaminergic (DA) neurons, restoring equipoise to the cytoarchitecture, preserving the host nigrostriatal pathway, and reducing alpha-synuclein aggregations (a pathological hallmark of PD). This action, called the "Chaperone Effect" represents a more tractible near-term method of using cells to address an unmet medical need. However, many questions remain in the process of developing these cellular therapeutic candidates. A major question is what is the best (safest & most efficacious way) to generate hNSCs? Directly from the fetal brain? From human embryonic stem cells? From human induced pluripotent cells? Also, would benefits be even greater if, in addition to harnessing the Chaperone Effect, the number of donor-derived DA neurons was also increased? And could choosing the right stem cell type &/or providing the right supportive molecules help achieve this? This study seeks to answer these questions. Importantly, we will continue to use the most representative model of human PD to do so, a model that not only mimics all of the human symptomatology but also all the side-effects of treatment; inattention to this latter aspect plagued earlier clinical trials in PD. Because of the unique team enlisted, these studies can be done at a fraction of the normal cost, allowing for parsimony in the use of research dollars, clearly a benefit to California taxpayers. Not only might California patients benefit in terms of their well-being, and the economy benefit from productive adults re-entering the work force & aging adults remaining in the work force, but it is likely that new intellectual property will emerge that will provide additional financial benefit to California stakeholders, both citizens & companies.
Progress Report: 
  • Parkinson's Disease (PD) is a devastating disorder, stealing vitality from vibrant, productive adults & draining our health care dollars. It is also an excellent model for studying other neurodegenerative conditions. We have discovered that human neural stem cells (hNSCs) may exert a significant beneficial impact in the most authentic, representative, & predictive animal model of actual human PD (the adult African/St. Kitts Green Monkeys exposed systemically to the neurotoxin MPTP). Interestingly, we have learned that, while some of the hNSCs differentiate into replacement dopamine (DA) neurons, much of the therapeutic benefit derived from a stem cell action we discovered called the “Chaperone Effect” – even hNSC-derived cells that do not become DA neurons contributed to the reversal of severe Parkinsonian symptoms by protecting endangered host DA neurons & their connections, restoring equipoise to the host nigrostriatal system, and reducing pathological hallmark of PD. While the ultimate goal may someday be to replace dead DA neurons, the Chaperone Effect represents a more tractable near-term method of using cells to address this serious condition. However, many questions remain in the process of developing these cellular therapeutic candidates. A major question is what is the best (safest, most efficacious) way to generate hNSCs? Directly from the fetal brain? From human embryonic stem cells? From skin cells reprogrammed to act like stem cells? Also, would benefits be even greater if, in addition to harnessing the Chaperone Effect, the number of stem cell-derived DA neurons was also increased? And could choosing the right stem cell type &/or providing the right supportive molecules help achieve this? This international study – which involves scientists from California, Madrid, Melbourne -- has been seeking to answer these questions. Importantly, we have been doing so using the most representative model of human PD, a model that not only mimics all of the human symptomatology but also all the side-effects of treatment; inattention to this latter aspect plagued earlier clinical trials in PD. A successful therapy for PD would not only be of great benefit for the many patients who now suffer from the disease, or who are likely to develop it as they age, but the results will help with other potential disease applications due to greater understanding of stem cell biology (particularly the Chaperone Effect, which represents “low hanging fruit”) as well as their potential complications and side effects.
  • To date, we have transplanted nearly 40 Parkinsonian non-human primates (NHPs) with a range of the different stem cell types described above. We have been able to generate neurons from some of these stem cells that appear to have the characteristics of the desired A9-type midbrain dopaminergic neuron lost in PD. Following transplantation, some of these stem cell derivatives appear to survive, integrate, & behave like dopaminergic neurons. Preliminary behavioral analysis of some engrafted NHPs offers encouraging results, suggesting an improvement in the Parkinsonism score in some of the animals. These NHPs will need to be followed for 1 year to insure that improvement continues & that no adverse events intervene. Over the next year, more stem cell candidates will be tested as we further optimize their preparation & differentiation.
  • We have made substantial progress in what will amount to the largest and most comprehensive head-to-head behavioral analysis of stem cell transplanted MPTP-NHPs to date and have identified cell types that show dramatic improvement in this model. Compared to the improvement observed with undifferentiated fetal CNS-derived hNSCs (the stem cell type in used Redmond et al, PNAS, 2007), 3 human stem cell candidates have shown a larger improvement in PS.
  • Summary of Achievements for this reporting period
  • • Comprehensive Behavioral data collection of 84 monkeys comprising over 10,000 observation data points
  • • Statistical analysis of Behavioral data collected to date identifies striking and statistically significant improvements in PS for several stem cell types. (Accordingly, NO-GO (or near NO-GO) cell types have been identified via comparison of levels of improvement or no improvement) [Figure 1]
  • • DNA samples collected in order to pursue the first ever complete genome sequencing of the Vervet in collaboration with the Washington University Genome Center
  • • Biochemistry sample processing and data collection of a 2nd large batch of samples completed.
  • The identification and development of an ideal cell-based therapy for a complex neurodegenerative disease requires the rigorous evaluation of both efficacy and safety of different sources and subtypes of hNSCs. The objective of this project has been to fully evaluate and identify the optimal stem cell type for a cell based therapy for refractory Parkinson’s Disease (PD) using the systemically MPTP-lesioned Old World non-human primate (NHP) (the St. Kitts Green Monkey) the most authentic animal model of the actual human disease. Among a list of plausible potentially therapeutic stem cell sources, 7 candidates have been evaluated head-to-head. The intent has been that the stem cell type (and its derivatives) safely producing the largest improvement in behavioral scores (based on a well-established NHP PD score – the Parkinson’s Factor Score [PFS] or ParkScore (which closely parallels the Hoehn–Yahr scale used in human patients, and is an accurate functional read-out of nigrostriatal dopamine [DA] activity) -- as well as a Healthy Behaviors Score [HBS] (similar to the activities-of-daily-living [ADL] on the major Parkinson’s rating scale and allows quantification of adverse events) -- will be advanced towards IND-enabling studies, to an actual IND filing, and ultimately a clinical trial.
  • Candidate cells have been transplanted into specific sub-regions of the nigrostriatal pathway of MPTP-lesioned NHPs. Animals undergo behavioral scoring for analysis of severity of Parkinsonian behavior at multiple time points pre- and post-cell transplantation. At sacrifice, biochemical measurements of DA content are made. Tissue is also analyzed to determine the fate of donor cells; the status of the host nigrostriatal pathway; the number of alpha-synuclein aggregates; degree of inflammation; any evidence of adverse events (e.g., tumor formation, cell overgrowth, emergence of cells inappropriate to the CNS).
  • We have made substantial progress in what will amount to the largest and most comprehensive head-to-head analysis of stem cell transplanted into any disease model to date, let alone behavioral analysis into a primate model of PD. Behavioral data have been collected on ~100 monkeys comprising >10,000 observation data points. We have identified a single Developmental Candidate (DC) that shows consistent and dramatic improvement in severely Parkinsonian NHPs (i.e., a significant decrease in Parkinsonian symptoms over the entire evaluation period), reflecting a restitution of DA function – human embryonic stem cell (hESC-derived) ventral mesencephalic (VM) precursors. We also suggest adding a mechanism to these cells for insuring unambiguous safety and invariant lineage commitment (a construct already generated and inserted into this DC, and recently engrafted into some initial monkeys).
  • We believe are ready for IND-enabling studies, including additional long-term pre-clinical behavioral studies of hESC-derived hVM cells that bear the above-mentioned “safety construct” – combined with additional biochemical assays of DA metabolism, histological assessments, serial profiling to insure genomic stability. Scale-up conditions for this DC are defined and reproducible and a working cell bank has been established.
  • Parkinson's Disease (PD) is a devastating disorder that is caused by the loss of a particular type of neuron in the brain. PD patients show movement abnormalities which worsen over time and significantly reduce the quality of life. Current treatments reduce the severity of these problems but very often the efficacy of these treatments gradually weakens over time leaving patients with few therapeutic options, some of which carry significant unwanted side effects. Since the development of growing undifferentiated human stem cells in the late 1990’s, much has been learned in regards to how to make these cells develop into neuronal cells, in particular the same type of neuron that is lost in a PD patient. Therefore, a cellular therapy has been envisioned for the treatment of PD, however, the complex nature of this disease requires higher level models in which potential therapies can be accurately evaluated before moving a therapy to clinical trials.
  • Previous work using human fetal tissue showed improvement of PD symptoms in an animal model and human clinical trials, however, distinctive movement abnormalities arose from the use of this treatment and combined with the ethical issues, it is not a viable therapeutic strategy. Recent work suggests that the use of embryonic stem cells for the treatment of PD may be possible but a direct comparison of the different types of cells derived from these was lacking. Additionally, tumors caused by these cells have been reported.
  • Our research efforts funded by this CIRM award allowed us to complete the largest stem cell therapy comparison for PD using the most accurate disease model available. Over the last 3 years we have evaluated the efficacy of 8 potential therapeutic cell types and 2 control cell types (in addition to various other control groups to rule out any possibility that the observations may have resulted from something other than cells). From these efforts we have confidently identified a strategy for producing cells that show a dramatic reduction in the PD symptoms in this model and these cells will be developed for clinical trials. Furthermore, we have incorporated a critical step for ensuring the safety of this cell therapy by including a purification technique that removes cells that may give rise to tumors or produce unknown or unwanted effects.

Sustained siRNA production from human MSC to treat Huntingtons Disease and other neurodegenerative disorders

Funding Type: 
Early Translational I
Grant Number: 
TR1-01257
ICOC Funds Committed: 
$2 753 559
Disease Focus: 
Huntington's Disease
Neurological Disorders
Stem Cell Use: 
Adult Stem Cell
Embryonic Stem Cell
Cell Line Generation: 
Adult Stem Cell
oldStatus: 
Closed
Public Abstract: 
One in every ten thousand people in the USA have Huntington's Disease, and it impacts many more. Multiple generations within a family can inherit the disease, resulting in escalating health care costs and draining family resources. This highly devastating and fatal disease touches all races and socioeconomic levels, and there are currently no cures. Screening for the mutant HD gene is available, but the at-risk children of an affected parent often do not wish to be tested since there are currently no early prevention strategies or effective treatments. HD is a challenging disease to treat. Not only do the affected, dying neurons need to be salvaged or replaced, but also the levels of the toxic mutant protein must be diminished to prevent further neural damage and to halt progression of the movement disorders and physical and mental decline that is associated with HD. Our application is focused on developing a safe and effective therapeutic strategy to reduce levels of the harmful mutant protein in damaged or at-risk neurons. We are using an RNA interference strategy – “small interfering RNA (siRNA)” to prevent the mutant protein from being produced in the cell. This strategy has been shown to be highly effective in animal models of HD. However, the inability to deliver the therapeutic molecules into the human brain in a robust and durable manner has thwarted scale-up of this potentially curative therapy into human trials. We are using mesenchymal stem cells, the “paramedics of the body”, to deliver the therapeutic siRNA directly into damaged cells. We have discovered that these stem cells are remarkably effective delivery vehicles, moving robustly through the tissue and infusing therapeutic molecules into each damaged cell that they contact. Thus we are utilizing nature's own paramedic system, but we are arming them with a new tool to also reduce mutant protein levels. Our novel system will allow the therapy to be carefully tested in preparation for future human cellular therapy trials for HD. The significance of our studies is very high because there are currently no treatments to diminish the amount of toxic mutant htt protein in the neurons of patients affected by Huntington’s Disease. There are no cures or successful clinical trials for HD. Our therapeutic strategy is initially examining models to treat HD, since the need is so acute. But this biological delivery system could also be used, in the future, for other neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS), spinocerebellar ataxia (SCA1), Alzheimer's Disease, and some forms of Parkinson's Disease, where reduction of the levels of a mutant or disease-activating protein could be curative. Development of this novel stem cell therapeutic and effective siRNA delivery system is extremely important for the community of HD and neurodegenerative disease researchers, patients, and families.
Statement of Benefit to California: 
It is estimated that one in 10,000 CA residents have Huntington’s Disease (HD). While the financial burden of Huntington’s Disease is estimated to be in the billions, the emotional burden on the friends and families of HD patients is immeasurable. Health care costs are extremely high for HD patients due to the decline in both body and mind. The lost ability of HD patients to remain in the CA workforce and to support their families causes additional financial strain on the state’s economy. HD is inherited as an autosomal dominant trait, which means that 50% of the children of an HD patient will inherit the disease and will in turn pass it on to 50% of their children. Individuals diagnosed through genetic testing are at risk of losing insurance coverage. Since there are currently no cures or successful clinical trials for HD, many are reluctant to be tested. The proposed project is designed in an effort to reach out to these individuals who, given that HD is given an orphan disease designation, may feel that they are completely forgotten and thus have little or no hope for their future or that of their families. To combat this devastating disease, we are using an RNA interference strategy, “small interfering RNA (siRNA),” to prevent the mutant htt protein from being produced in the cell. This strategy has been shown to be highly effective in animal models of HD. However the siRNA needs to be delivered to the brain or central nervous system in a continual manner, to destroy the toxic gene products as they are produced. There are currently no methods to infuse or produce siRNA in the brain, in a safe and sustained manner. Therefore the practical clinical use of this dramatically effective potential therapeutic application is currently thwarted. Here we propose a solution, using adult mesenchymal stem cells (MSC) modified to infuse siRNA directly into diseased or at-risk neurons in the striata of HD patients, to decrease the levels of the toxic mutant htt protein. MSC are known as the “paramedics of the body" and have been demonstrated through clinical trials to be safe and to have curative effects on damaged tissue. Even without the modification to reduce the mutant protein levels, the infused MSC will help repair the damaged brain tissue by promoting endogenous neuronal growth through secreted growth factors, secreting anti-apoptotic factors, and regulating inflammation. Our therapeutic strategy will initially examine models to treat HD, since the need is so acute. But our biological delivery system could also be applied to other neurodegenerative disorders such as ALS, some forms of Parkinson’s Disease, and Alzheimer’s Disease, by using siRNA to interfere with key pathways in development of the pathology. This would be the first cellular therapy for HD patients and would have a major impact on those affected in California. In addition, the methods that we are developing will have far-reaching effects for other neurodegenerative disorders.
Progress Report: 
  • During the first year of funding we have made significant progress toward the goals of the funded CIRM grant TR1-01257: Sustained siRNA production from human MSC to treat Huntington’s disease and other neurodegenerative disorders.
  • The overall goal of the grant is to use human mesenchymal stem cells (MSC) as safe delivery vehicles to knock down levels of the mutant Huntingtin (htt) RNA and protein in the brain. There is mounting evidence in trinucleotide repeat disorders that the RNA, as well as the protein, is toxic and thus we will need to significantly reduce levels of both in order to have a durable impact on this devastating disease.
  • This year we have shown that human MSC engineered to produce anti-htt siRNA can directly transfer enough RNA interfering molecules into neurons in vitro to achieve significant reduction in levels of the htt protein. This is a significant achievement and a primary goal of our proposed studies, and demonstrates that the hypothesis for our proposed studies is valid. The transfer occurs through direct cell-to-cell transfer of siRNA, and we have filed an international patent for this process, working closely with our Innovation Access Program at UC Davis. A manuscript documenting the results of these studies is in preparation.
  • We continue to explore the precise methods by which the cell-to-cell transfer of small RNA molecules occurs, working in close collaboration with the national Center for Biophotonics Science and Technology at UC Davis. This Center is located across the street from our CIRM-funded Institute for Regenerative Cures (IRC) where our laboratory is located, and has equipment that allows visualization of protein-protein interactions in high clarity and detail. The proximity of our HD team researchers in the IRC to the Center for Biophotonics has been an important asset to our project and a collaborative manuscript is in preparation.
  • During year two of the proposed studies we will continue to document levels of reduction of the toxic htt protein in different types of neurons, including medium spiny neurons (MSN) derived from HD patient induced pluripotent stem cells (iPSC). We have made significant advances in developing the tools for these studies, including HD iPSC line generation and MSN maturation from human pluripotent cells in culture. A manuscript on improved techniques for generating MSN from pluripotent cells is in preparation. We have also worked closely with our colleagues at the UC Davis MIND Institute to achieve improved maturation and electrical activity in neurons derived from human pluripotent stem cells in vitro, and we are examining the impact of human MSC on enhancing survival of damaged human neurons.
  • In the second year of funding we will test efficacy of the siRNA-mediated knockdown of the mutant human htt RNA and protein in the brains of our newly developed strain of immune deficient Huntington's disease mice. This strain was developed by our teams at UC Davis to allow testing of human cells in the mice, since the current strains of HD mice will reject human stem cells. A manuscript describing generation of this novel HD mouse strain is in preparation, in collaboration with our nationally prominent Center for Mouse Biology.
  • Behavioral studies will be conducted in this strain with and without the MSC/siRNA-mediated knockdown of the mutant protein, through years 2-3, in collaboration with our well established mouse neurobehavioral core at the UC Davis Center for Neurosciences. We have documented the safety of intrastriatal injection of human MSC in immune deficient mice and will next test the efficacy of human MSC engineered to continually produce the siRNA to knock down the mutant htt protein in vivo.
  • As added leverage for this grant program, and supported entirely by philanthropic donations from the community committed to curing HD, we have performed IND-enabling studies in support of an initial planned clinical trial that will use normal donor MSC (non-engineered) to validate their significant neurotrophic effects in the brain. These trophic effects have been documented in animal models. The planned study will be a phase 1 safety trial. We have completed the clinical protocol design and have received feedback from the Food and Drug Administration. We will be conducting additional studies in response to their queries, over the next 6-10 months, through a pilot grant obtained from our Clinical Translational Science Center (CTSC), which is located in the same building as our Institute. Upon completion of these additional studies we will submit the updated IND application to the FDA. MSCs for this project have been expanded and banked using standard operating procedures in place in the Good Manufacturing Practice Facility in the CIRM/UC Davis Institute for Regenerative Cures.
  • From the funded studies 4 manuscripts are now in preparation, a chapter is in press and a review paper on MSC to treat neurodegenerative diseases is in press.
  • During the second year of funding we have made significant progress toward the goals of the funded CIRM grant TR1-01257: Sustained siRNA production from human MSC to treat Huntington’s disease and other neurodegenerative disorders.
  • The overall goal of the grant is to use human mesenchymal stem cells (MSC) as safe delivery vehicles to knock down levels of the mutant Huntingtin (htt) RNA and protein in the brain. During the second year we have more fully characterized our development candidate; MSC/anti-htt. We have documented that normal human donor MSC engineered to produce anti-htt siRNA can directly transfer enough RNA interfering molecules into neurons in vitro to achieve significant reduction in levels of the htt protein. We reported this work at the Annual meeting of the American Academy of Neurology (G Mitchell, S Olson, K Pollock, A Kambal, W Cary, K Pepper, S Kalomoiris, and J Nolta. Mesenchymal Stem Cells as a Delivery Vehicle for Intercellular Delivery of RNAi to Treat Huntington's disease. AAN IN10-1.010, 2011) and have recently completed and submitted a manuscript describing these results (S Olson, A Kambal, K Pollock, G Mitchell, H Stewart, S Kalomoiris, W Cary, C Nacey, K Pepper, J Nolta. Mesenchymal stem cell-mediated RNAi transfer to Huntington's disease affected neuronal cells for reduction of huntingtin. Submitted, In Review, July 2011).
  • We have explored the molecular methods by which the cell-to-cell transfer of small RNA molecules occurs, working in close collaboration with the national Center for Biophotonics Science and Technology at UC Davis. This Center is located across the street from our CIRM-funded Institute for Regenerative Cures (IRC) where our laboratory is located, and has equipment that allows visualization of protein-siRNA interactions in high clarity and detail. The proximity of our HD team researchers in the IRC to the Center for Biophotonics has been an important asset to our project. This work was also presented at AAN 2011, and a collaborative manuscript is in preparation for submission (S Olson, G McNerny, K Pollock, F Chuang, T Huser and J Nolta, Visualization of siRNA Complexed to RISC Machinery: Demonstrating Intercellular siRNA Transfer by Imaging Activity. MS in preparation, Presented at AAN 2011: IN4-1.014).
  • In the second year of funding we developed the models for in vivo efficacy testing of the siRNA-mediated knockdown of the mutant human htt RNA and protein in the brains of established and new strains of Huntington's disease mice. Behavioral studies were conducted in two strains, the R6/2 immune competent mice and our new immune deficient strain, the NSG/HD, in comparison to normal littermate controls that are not affected by HD. We established the batteries of behavioral tests that are now needed to test efficacy of our development candidate in the brain, in year three. Established tests include rotarod, treadscan, pawgrip, spontaneous activity, nesting, locomotor activity, and the characteristic HD mouse hindlimb clasping phenotype. In addition we monitor the status of weight and tremor, grooming, eyes, hair, body position, and tail position, which all change over time in HD mice. These tests are conducted at 48 hour intervals by two highly trained technicians who are blinded to the treatment that the mouse had received. These behavioral and phenotypic tests have been established at the level of Good laboratory practices in our new Institute for Regenerative Cures shower-in barrier facility vivarium. We have documented the biosafety of intrastriatal injection of human MSC in immune deficient mice and are now examining the in vivo efficacy of the development candidate: human MSC engineered to continually produce the siRNA to knock down the mutant htt protein in vivo, which will be completed in year three.
  • As added leverage for this funded grant program, and supported entirely by philanthropic donations from the community committed to curing HD, we have performed IND-enabling studies in support of an initial planned clinical trial that will use normal donor MSC (non-engineered) to validate their significant neurotrophic effects in the brain. These trophic effects have been documented in animal models. The planned study will be a phase 1 safety trial. We have completed the clinical protocol design and have received feedback from the Food and Drug Administration. We will be conducting additional studies in response to their queries, over the next 6-10 months, through a pilot grant obtained from our Clinical Translational Science Center (CTSC), which is located in the same building as our Institute. Upon completion of these additional studies we will submit the updated IND application to the FDA. MSCs for this project have been expanded and banked using standard operating procedures in place in the Good Manufacturing Practice Facility in the CIRM/UC Davis Institute for Regenerative Cures.
  • During the three years of funding we made significant progress toward the goals of the funded CIRM grant TR1-01257: Sustained siRNA production from human MSC to treat Huntington’s disease and other neurodegenerative disorders.
  • The overall goal of the grant is to use human mesenchymal stem cells (MSC) as safe delivery vehicles to knock down levels of the mutant Huntingtin (htt) RNA and protein in the brain. There is mounting evidence in trinucleotide repeat disorders that the RNA, as well as the protein, is toxic and thus we will need to significantly reduce levels of both in order to have a durable impact on this devastating disease.
  • We initially demonstrated that human MSC engineered to produce anti-htt siRNA can directly transfer enough RNA interfering molecules into neuronal cells in vitro to achieve significant reduction in levels of the htt protein. This is a significant achievement and a primary goal of our proposed studies, and demonstrates that the hypothesis for our proposed studies is valid. The transfer occurs either through direct cell-to-cell transfer of siRNA or through exosome transfer, and we filed an international patent for this process, working closely with our Innovation Access Program at UC Davis. This patent has IP sharing with CIRM.
  • An NIH transformative grant was awarded to Dr. Nolta to further explore these exciting findings. This provides funding for five years to further define and optimize the siRNA transfer mechanism.
  • A manuscript documenting the results of these studies was published:
  • S Olson, A Kambal, K Pollock, G Mitchell, H Stewart, S Kalomoiris, W Cary, C Nacey, K Pepper, J Nolta. Examination of mesenchymal stem cell-mediated RNAi transfer to Huntington's disease affected neuronal cells for reduction of huntingtin. Molecular and Cellular Neuroscience; 49(3):271-81, 2012.
  • Also a review was published with our collaborator Dr. Gary Dunbar:
  • S Olson, K Pollock, A Kambal, W Cary, G Mitchell, J Tempkin, H Stewart, J McGee, G Bauer, T Tempkin, V Wheelock, G Annett, G Dunbar and J Nolta, Genetically Engineered Mesenchymal Stem Cells as a Proposed Therapeutic for Huntington’s disease. Molecular Neurobiology; 45(1):87-98, 2012.
  • We examined the potential efficacy of injecting relatively small numbers of MSCs engineered to produce ant-htt siRNA into the striata of the HD mouse strain R6/2, in three series of experiments. Results of these experiments did not reach significance for the test agent as compared to controls. The slope of the decline in rotarod performance was less with the test agent, and development of clasping behavior was slightly delayed after injection of MSC/aHtt, but this caught up to the controls and was not significant after day 60.
  • Our conclusions are that the R6/2 strain is too rapidly progressing to see efficacy with the test agent, and also that improved methods of siRNA transfer from cell to cell are needed. We are currently working on this problem through the NIH transformative award, and will use the YAC 128 strain, which has a more slowly progressing phenotype, for all future studies. These mice are now bred and in use in our vivarium, for the MSC/BDNF studies funded through our disease team grant.
  • Through this translational grant funding we have also developed in vitro potency assays, using human embryonic stem cell-derived neurons and medium spiny neurons, as we have described in prior reports. The differentiation techniques (funded through other grants to our group) have now been published:1-3
  • 1. Liu J, Githinji J, McLaughlin B, Wilczek K, Nolta J. Role of miRNAs in Neuronal Differentiation from Human Embryonic Stem Cell-Derived Neural Stem Cells. Stem Cell Rev;8(4):1129-37, 2012.
  • 2. Jun-feng Feng, Jing Liu, Xiu-zhen Zhang, Lei Zhang, Ji-yao Jiang, Nolta J, Min Zhao. Guided Migration of Neural Stem Cells Derived from Human Embryonic Stem Cells by an Electric Field. Stem Cells. Feb; 30(2):349-55, 2012.
  • 3. Liu J, Koscielska KA, Cao Z, Hulsizer S, Grace N, Mitchell G, Nacey C, Githinji J, McGee J, Garcia-Arocena D, Hagerman RJ, Nolta J, Pessah I, Hagerman PJ. Signaling defects in iPSC-derived fragile X premutation neurons. Hum Mol Genet. 21(17):3795-805. 2012.

Enhancing healing via Wnt-protein mediated activation of endogenous stem cells

Funding Type: 
Early Translational I
Grant Number: 
TR1-01249
ICOC Funds Committed: 
$6 762 954
Disease Focus: 
Bone or Cartilage Disease
Stroke
Neurological Disorders
Heart Disease
Neurological Disorders
Skin Disease
Stem Cell Use: 
Adult Stem Cell
oldStatus: 
Active
Public Abstract: 
All adult tissues contain stem cells. Some tissues, like bone marrow and skin, harbor more adult stem cells; other tissues, like muscle, have fewer. When a tissue or organ is injured these stem cells possess a remarkable ability to divide and multiply. In the end, the ability of a tissue to repair itself seems to depend on how many stem cells reside in a particular tissue, and the state of those stem cells. For example, stress, disease, and aging all diminish the capacity of adult stem cells to self-renew and to proliferate, which in turn hinders tissue regeneration. Our strategy is to commandeer the molecular machinery responsible for adult stem cell self-renewal and proliferation and by doing so, stimulate the endogenous program of tissue regeneration. This approach takes advantage of the solution that Nature itself developed for repairing damaged or diseased tissues, and controls adult stem cell proliferation in a localized, highly controlled fashion. This strategy circumvents the immunological, medical, and ethical hurdles that exist when exogenous stem cells are introduced into a human. When utilizing this strategy the goal of reaching clinical trials in human patients within 5 years becomes realistic. Specifically, we will target the growing problem of neurologic, musculoskeletal, cardiovascular, and wound healing diseases by local delivery of a protein that promotes the body’s inherent ability to repair and regenerate tissues. We have evidence that this class of proteins, when delivered locally to an injury site, is able to stimulate adult tissue stem cells to grow and repair/replace the deficient tissue following injury. We have developed technologies to package the protein in a specialized manner that preserves its biological activity but simultaneously restricts its diffusion to unintended regions of the body. For example, when we treat a skeletal injury with this packaged protein we augment the natural ability to heal bone by 350%; and when this protein is delivered to the heart immediately after an infarction cardiac output is improved and complications related to scarring are reduced. This remarkable capacity to augment tissue healing is not limited to bones and the heart: the same powerful effect can be elicited in the brain, and skin injuries. The disease targets of stroke, bone fractures, heart attacks, and skin wounds and ulcers represent an enormous health care burden now, but this burden is expected to skyrocket because our population is quickly aging. Thus, our proposal addresses a present and ongoing challenge to healthcare for the majority of Californians, with a novel therapeutic strategy that mimics the body’s inherent repair mechanisms.
Statement of Benefit to California: 
Californians represent 1 in 7 Americans, and make up the single largest healthcare market in the United States. The diseases and injuries that affect Californians affect the rest of the US, and the world. For example, stroke is the third leading cause of death, with more than 700,000 people affected every year. It is a leading cause of serious long-term disability, with an estimated 5.4 million stroke survivors currently alive today. Symptoms of musculoskeletal disease are the number two most cited reasons for visit to a physician. Musculoskeletal disease is the leading cause of work-related and physical disability in the United States, with arthritis being the leading chronic condition reported by the elderly. In adults over the age of 70, 40% suffer from osteoarthritis of the knee and of these nearly 80% have limitation of movement. By 2030, nearly 67 million US adults will be diagnosed with arthritis. Cardiovascular disease is the leading cause of death, and is a major cause of disability worldwide. The annual socioeconomic burden posed by cardiovascular disease is estimated to exceed $400 billion annually and remains a major cause of health disparities and rising health care costs. Skin wounds from burns, trauma, or surgery, and chronic wounds associated with diabetes or pressure ulcer, exact a staggering toll on our healthcare system: Burns alone affect 1.25M Americans each year, and the economic global burden of these injuries approaches $50B/yr. In California alone, the annual healthcare expenditures for stroke, skeletal repair, heart attacks, and skin wound healing are staggering and exceed 700,000 cases, 3.5M hospital days, and $34B. We have developed a novel, protein-based therapeutic platform to accelerate and enhance tissue regeneration through activation of adult stem cells. This technology takes advantage of a powerful stem cell factor that is essential for the development and repair of most of the body’s tissues. We have generated the first stable, biologically active recombinant Wnt pathway agonist, and showed that this protein has the ability to activate adult stem cells after tissue injury. Thus, our developmental candidate leverages the body’s natural response to injury. We have generated exciting preclinical results in a variety of animals models including stroke, skeletal repair, heart attack, and skin wounding. If successful, this early translational award would have enormous benefits for the citizens of California and beyond.
Progress Report: 
  • In the first year of CIRM funding our objectives were to optimize the activity of the Wnt protein for use in the body and then to test, in a variety of injury models, the effects of this lipid-packaged form of Wnt. We have made considerable progress on both of these fronts. For example, in Roel Nusse and Jill Helms’ groups, we have been able to generate large amounts of the mouse form of Wnt3a protein and package it into liposomal vesicles, which can then be used by all investigators in their studies of injury and repair. Also, Roel Nusse succeeded in generating human Wnt3a protein. This is a major accomplishment since our ultimate goal is to develop this regenerative medicine tool for use in humans. In Jill Helms’ lab we made steady progress in standardizing the activity of the liposomal Wnt3a formulation, and this is critically important for all subsequent studies that will compare the efficacy of this treatment across multiple injury repair scenarios.
  • Each group began testing the effects of liposomal Wnt3a treatment for their particular application. For example, in Theo Palmer’s group, the investigators tested how liposomal Wnt3a affected cells in the brain following a stroke. We previously found that Wnt3A promotes the growth of neural stem cells in a petri dish and we are now trying to determine if delivery of Wnt3A can enhance the activity of endogenous stem cells in the brain and improve the level of recovery following stroke. Research in the first year examined toxicity of a liposome formulation used to deliver Wnt3a and we found it to be well tolerated after injection into the brains of mice. We also find that liposomal Wnt3a can promote the production of new neurons following stroke. The ongoing research involves experiments to determine if these changes in stem cell activity are accompanied by improved neurological function. In Jill Helms’ group, the investigators tested how liposomal Wnt3a affected cells in a bone injury site. We made a significant discovery this year, by demonstrating that liposomal Wnt3a stimulates the proliferation of skeletal progenitor cells and accelerates their differentiation into osteoblasts (published in Science Translational Medicine 2010). We also started testing liposomal Wnt3a for safety and toxicity issues, both of which are important prerequisites for use of liposomal Wnt3a in humans. Following a heart attack (i.e., myocardial infarction) we found that endogenous Wnt signaling peaks between post-infarct day 5-7. We also found that small aggregates of cardiac cells called cardiospheres respond to Wnt in a dose-responsive manner. In skin wounds, we tested the effect of boosting Wnt signaling during skin wound healing. We found that the injection of Wnt liposomes into wounds enhanced the regeneration of hair follicles, which would otherwise not regenerate and make a scar instead. The speed and strength of wound closure are now being measured.
  • In aggregate, our work on this project continues to move forward with a number of great successes, and encouraging data to support our hypothesis that augmenting Wnt signaling following tissue injury will provide beneficial effects.
  • In the second year of CIRM funding our objectives were to optimize packaging of the developmental candidate, Wnt3a protein, and then to continue to test its efficacy to enhance tissue healing. We continue to make considerable progress on the stated objectives. In Roel Nusse’s laboratory, human Wnt3a protein is now being produced using an FDA-approved cell line, and Jill Helms’ lab the protein is effectively packaged into lipid particles that delay degradation of the protein when it is introduced into the body.
  • Each group has continued to test the effects of liposomal Wnt3a treatment for their particular application. In Theo Palmer’s group we have studied how liposomal Wnt3a affects neurogenesis following stroke. We now know that liposomal Wnt3a transiently stimulates neural progenitor cell proliferation. We don’t see any functional improvement after stroke, though, which is our primary objective.
  • In Jill Helms’ group we’ve now shown that liposomal Wnt3a enhances fracture healing and osseointegration of dental and orthopedic implants and now we demonstrate that liposomal Wnt3a also can improve the bone-forming capacity of bone marrow grafts, especially when they are taken from aged animals.
  • We’ve also tested the ability of liposomal Wnt3a to improve heart function after a heart attack (i.e., myocardial infarction). Small aggregates of cardiac progenitor cells called cardiospheres proliferate to Wnt3a in a dose-responsive manner, and we see an initial improvement in cardiac function after treatment of cells with liposomal Wnt3a. the long-term improvements, however, are not significant and this remains our ultimate goal. In skin wounds, we tested the effect of boosting Wnt signaling during wound healing. We found that the injection of liposomal Wnt3a into wounds enhanced the regeneration of hair follicles, which would otherwise not regenerate and make a scar instead. The speed of wound closure is also enhanced in regions of the skin where there are hair follicles.
  • In aggregate, our work continues to move forward with a number of critical successes, and encouraging data to support our hypothesis that augmenting Wnt signaling following tissue injury will provide beneficial effects.
  • Every adult tissue harbors stem cells. Some tissues, like bone marrow and skin, have more adult stem cells and other tissues, like muscle or brain, have fewer. When a tissue is injured, these stem cells divide and multiply but only to a limited extent. In the end, the ability of a tissue to repair itself seems to depend on how many stem cells reside in a particular tissue, and the state of those stem cells. For example, stress, disease, and aging all diminish the capacity of adult stem cells to respond to injury, which in turn hinders tissue healing. One of the great unmet challenges for regenerative medicine is to devise ways to increase the numbers of these “endogenous” stem cells, and revive their ability to self-renew and proliferate.
  • The scientific basis for our work rests upon our demonstration that a naturally occurring stem cell growth factor, Wnt3a, can be packaged and delivered in such a way that it is robustly stimulates stem cells within an injured tissue to divide and self-renew. This, in turn, leads to unprecedented tissue healing in a wide array of bone injuries especially in aged animals. As California’s population ages, the cost to treat such skeletal injuries in the elderly will skyrocket. Thus, our work addresses a present and ongoing challenge to healthcare for the majority of Californians and the world, and we do it by mimicking the body’s natural response to injury and repair.
  • To our knowledge, there is no existing technology that displays such effectiveness, or that holds such potential for the stem cell-based treatment of skeletal injuries, as does a L-Wnt3a strategy. Because this approach directly activates the body’s own stem cells, it avoids many of the pitfalls associated with the introduction of foreign stem cells or virally reprogrammed autologous stem cells into the human body. In summary, our data show that L-Wnt3a constitutes a viable therapeutic approach for the treatment of skeletal injuries, especially those in individuals with diminished healing potential.
  • This progress report covers the period between Sep 01 2012through Aug 31 2013, and summarizes the work accomplished under ET funding TR1-01249. Under this award we developed a Wnt protein-based platform for activating a patient’s own stem cells for the purpose of tissue regeneration.
  • At the beginning of our grant period we generated research grade human WNT3A protein in quantities sufficient for all our discovery experiments. We then tested the ability of this WNT protein therapeutic to improve the healing response in animal models of stroke, heart attack, skin wounding, and bone fracture. These experimental models recapitulated some of the most prevalent and debilitating human diseases that collectively, affect millions of Californians.
  • At the end of year 2, we assembled an external review panel to select the promising clinical indication. The scientific advisory board unanimously selected skeletal repair as the leading indication. The WNT protein is notoriously difficult to purify; consequently in year 3 we developed new methods to streamline the purification of WNT proteins, and the packaging of the WNT protein into liposomal vesicles that stabilized the protein for in vivo use.
  • In years 3 and 4 we continued to accrue strong scientific evidence in both large and small animal models that a WNT protein therapeutic accelerates bone regeneration in critical size bony non-unions, in fractures, and in cases of implant osseointegration. In this last year of funding, we clarified and characterized the mechanism of action of the WNT protein, by showing that it activates endogenous stem cells, which in turn leads to faster healing of a range of different skeletal defects.
  • In this last year we also identified a therapeutic dose range for the WNT protein, and developed a route and method of delivery that was simultaneously effective and yet limited the body’s exposure to this potent stem cell factor. We initiated preliminary safety studies to identify potential risks, and compared the effects of WNT treatment with other commercially available bone growth factors. In sum, we succeeded in moving our early translational candidate from exploratory studies to validation, and are now ready to enter into the IND-enabling phase of therapeutic candidate development.
  • This progress report covers the period between Sep 01 2013 through April 30 2014, and summarizes the work accomplished under ET funding TR101249. Under this award we developed a Wnt protein-based platform for activating a patient’s own stem cells for purposes of tissue regeneration.
  • At the beginning of our grant period we generated research grade human WNT3A protein in quantities sufficient for all our discovery experiments. We then tested the ability of this WNT protein therapeutic to improve the healing response in animal models of stroke, heart attack, skin wounding, and bone fracture. These experimental models recapitulated some of the most prevalent and debilitating human diseases that collectively, affect millions of Californians. At the conclusion of Year 2 an external review panel was assembled and charged with the selection of a single lead indication for further development. The scientific advisory board unanimously selected skeletal repair as the lead indication.
  • In year 3 we accrued addition scientific evidence, using both large and small animal models, demonstrating that a WNT protein therapeutic accelerated bone healing. Also, we developed new methods to streamline the purification of WNT proteins, and improved our method of packaging of the WNT protein into liposomal vesicles (e.g., L-WNT3A) for in vivo use.
  • In year 4 we clarified the mechanism of action of L-WNT3A, by demonstrating that it activates endogenous stem cells and therefore leads to accelerated bone healing. We also continued our development studies, by identifying a therapeutic dose range for L-WNT3A, as well as a route and method of delivery that is both effective and safe. We initiated preliminary safety studies to identify potential risks, and compared the effects of L-WNT3A with other, commercially available bone growth factors.
  • In year 5 we initiated two new preclinical studies aimed at demonstrating the disease-modifying activity of L-WNT3A in spinal fusion and osteonecrosis. These two new indications were chosen by a CIRM review panel because they represent an unmet need in California and the nation. We also initiated development of a scalable manufacturing and formulation process for both the WNT3A protein and L-WNT3A formulation. These two milestones were emphasized by the CIRM review panel to represent major challenges to commercialization of L-WNT3A; consequently, accomplishment of these milestones is a critical yardstick by which progress towards an IND filing can be assessed.

Using patient-specific iPSC derived dopaminergic neurons to overcome a major bottleneck in Parkinson's disease research and drug discovery

Funding Type: 
Early Translational I
Grant Number: 
TR1-01246
ICOC Funds Committed: 
$3 701 766
Disease Focus: 
Parkinson's Disease
Neurological Disorders
Collaborative Funder: 
Germany
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Closed
Public Abstract: 
The goals of this study are to develop patient-specific induced pluripotent cell lines (iPSCs) from patients with Parkinson’s disease (PD) with defined mutations and sporadic forms of the disease. Recent groundbreaking discoveries allow us now to use adult human skin cells, transduce them with specific genes, and generate cells that exhibit characteristics of embryonic stem cells, termed induced pluripotent stem cells (iPSCs). These lines will be used as an experimental pre-clinical model to study disease mechanisms unique to PD. We predict that these cells will not only serve an ‘authentic’ model for PD when further differentiated into the specific dopaminergic neurons, but that these cells are pathologically affected with PD. The specific objectives of these studies are to (1) establish a bank of iPSCs from patients with idiopathic PD and patients with defined mutations in genes associated with PD, (2) differentiate iPSCs into dopaminergic neurons and assess neurochemical and neuropathological characteristics of PD of these cells in vitro, and (3) test the hypothesis that specific pharmacologic agents can be used to block or reverse pathological phenotypes. The absence of cellular models of Parkinson’s disease represents a major bottleneck in the scientific field of PD, which, if solved in this collaborative effort, would be instantly translated into a wide range of clinical applications, including drug discovery. This research is highly translational, as the final component is aimed at testing lead compounds that could be neuroprotective, and ultimately at developing a high-throughput drug screening program to discover new disease modifying compounds. This is an essential avenue if we want to offer our patients a new therapeutic approach that can give them a near normal life after being diagnosed with this progressively disabling disease.
Statement of Benefit to California: 
Approx. 36,000-60,000 people in the State of California are affected with Parkinson’s disease (PD), a common neurodegenerative disease that causes a high degree of disability and financial burden for our health care system. It is estimated that the number of PD cases will double by the year 2030. We have a critical need for novel therapies that will prevent or even reverse neuronal cell loss of specific neurons in the brain of patients. This collaborative proposal will provide real benefits and values to the state of California and its citizens in providing new approaches for understanding disease mechanisms, diagnostic tools and drug discovery of novel treatment for PD. Reprogramming of adult skin cells to a pluripotent state is the underlying mechanism upon which this application is built upon and offers an attractive avenue of research in this case to develop an ‘authentic’ pre-clinical model of PD. The rationale for the proposed research is that differentiated pluripotent stem cells from patients with known genetic forms of PD will recapitulate in vitro one or more of the key molecular aspects of neural degeneration associated with PD and thus provide an entirely novel human cellular system for investigation PD-related disease pathways and for drug discovery. The impact of this collaborative research project, if successful, is difficult to over-estimate. The scientific field has been struggling with the inability to directly access cells that are affected by the disease process that underlies PD and therefore all research and drug discovery has relied on ”best guess” models of the disease. Thus, the absence of cellular models of Parkinson’s disease represents a huge bottleneck in the field.
Progress Report: 
  • In the first year of the CIRM Early translational research award, we established a bank of 51 cell lines derived from skin cells of patients with Parkinson’s disease that carry specific mutations in known genes that cause PD as well as sporadic PD patients. We also recruited matched healthy individuals that serve as controls.
  • In a next step, we reprogrammed (‘rejunivated’) 17 samples of skin cells to derive pluripotent stem cells (iPSC) that closely resemble human embryonic stem cells characterized by biochemical and molecular techniques. We also optimize this process by introducing factors the will be removed after successful reprogramming.
  • We have now built a foundation for the next milestones and made already progress on the differentiation into authentic dopamine producing cells, and we have developed assays to assess the Parkinson’s disease-specific pathological phenotype of the dopamine neurons.
  • The goal of this CIRM early translational grant is to develop a model for “Parkinson’s disease (PD) in a culture dish” using patient-specific induced pluripotent stem cell lines (iPS). The underlying idea is to utilize these lines as an experimental pre-clinical model to study disease mechanisms unique to PD that could lay the foundation for drug discovery.
  • Over the last year, we have expanded our patient skin cell bank to 57 cell lines and the iPS cell bank to 39 well-characterized pluripotent stem cell lines from PD patients and healthy controls individuals. We have improved current protocols of neuronal differentiation from patient-derived iPS lines into dopamine producing neurons and can show consistency and reproducibility of making midbrain dopamine expressing nerve cells.
  • In our first publication (Nguyen et al. 2011), we describe for the first time differences in iPS-derived neurons from a PD patient with a common causative mutation in the LRRK2 gene. These patient cells are more susceptible for cellular toxins leading ultimately to more cell degeneration and cell death.
  • We are also investigating a common disease mechanism implicated in PD, which is mitochondrial dysfunction. In skin cells of a patient we were able to find profound deficits of mitochondrial function compared to control lines and we are now in the process of confirming these results in neural precursors and mature dopamine neurons.
  • Overall, we have made substantial progress towards the goal of this grant which is the a new cell culture model of PD which can replicate PD-related cellular pathology.
  • The goal of this CIRM early translational grant is to develop a model for “Parkinson’s disease (PD) in a culture dish” using patient-specific induced pluripotent stem cell lines (iPS). The underlying idea is to utilize these lines as an experimental pre-clinical model to study disease mechanisms unique to PD that could lay the foundation for drug discovery.
  • Over the last year, we have expanded our patient skin cell bank to 61 cell lines and the iPS cell bank to 51 well-characterized pluripotent stem cell lines from PD patients and healthy controls individuals. We have improved current protocols of neuronal differentiation from patient-derived iPS lines into dopamine producing neurons and can show consistency and reproducibility of making midbrain dopamine expressing nerve cells. This has been now published in Mak et al. 2012. Furthermore, we also develop new protocols to also derive other neuronal subtypes and glia, which are the support cells in the brain, to build co-culture systems. These co-cultures might represent closer the physiological conditions in the brain.
  • In our first publication (Nguyen et al. 2011), we describe for the first time differences in iPS-derived neurons from a PD patient with a common causative mutation in the LRRK2 gene. These patient cells are more susceptible for cellular toxins leading ultimately to more cell degeneration and cell death. In a second publication Byers et al. 2011, we describe similar findings for a different mutation in the alpha-synuclein gene where the normal protein is overexpressed due to a triplication of the gene locus.
  • We are also investigating a common disease mechanism implicated in PD, which is mitochondrial dysfunction. In skin cells of a patient we were able to find profound deficits of mitochondrial function compared to control lines and we are now in the process of confirming these results in neural precursors and mature dopamine neurons.
  • We are expanding the assay development to other disease-related mechanisms such as deficits in outgrowth of neuronal projections and protein aggregation.
  • Overall, through this program we have developed an invaluable resource of patient-derived cell lines that will be crucial for understanding disease mechanisms and drug discovery. We also showed proof that these cell lines can indeed recapitulates important aspects of disease and are therefore valuable assets as research tools.

Neural Stem Cells as a Developmental Candidate to Treat Alzheimer Disease

Funding Type: 
Early Translational I
Grant Number: 
TR1-01245
ICOC Funds Committed: 
$3 599 997
Disease Focus: 
Aging
Alzheimer's Disease
Neurological Disorders
Collaborative Funder: 
Victoria, Australia
Stem Cell Use: 
Adult Stem Cell
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 
Alzheimer disease (AD), the most common cause of dementia among the elderly and the third leading cause of death, presently afflicts over 5 million people in the USA, including over 500,000 in California. Age is the major risk factor, with 5% of the population over age 65 affected, with the incidence doubling every 5 years thereafter, such that 40-50% of those over age 85 are afflicted. Being told that one suffers from AD is one of the most devastating diagnoses a patient (and their family/caregivers) can ever receive, dooming the patient to a decade or more of progressive cognitive decline and eventual loss of all memory. At the terminal stages, the patients have lost all reasoning ability and are usually bed-ridden and unable to care for themselves. As the elderly represent the fastest growing segment of our society, there is an urgent need to develop therapies to delay, prevent or treat AD. If the present trend continues and no therapy is developed, over 16 million Americans will suffer from AD by 2050, placing staggering demands on our healthcare and economic systems. Thus, supporting AD research is a wise and prudent investment, particularly focusing on the power that stem cell biology offers. Currently, there is no cure or means of preventing AD. Existing treatments provide minor symptomatic relief– often associated with severe side effects. Multiple strategies are likely needed to prevent or treat AD, including the utilization of cell based approaches. In fact, our preliminary studies indicate that focusing on the promise of human stem cell biology could provide a meaningful therapy for a disease for which more traditional pharmaceutical approaches have failed. We aim to test the hypothesis that neural stem cells represent a novel therapeutic strategy for the treatment of AD. Our broad goal is to determine whether neural stem cells can be translated from the bench to the clinic as a therapy for AD. This proposal builds on extensive preliminary data that support the feasibility of neural stem cell-based therapies for the treatment of AD. Thus, this proposal focuses on a development candidate for treating Alzheimer disease. To translate our initial stem cell findings into a future clinical application for treating AD, we assembled a world class multi-disciplinary team of scientific leaders from the fields of stem cell biology, animal modeling, neurodegeneration, immunology, genomics, and AD clinical trials to collaborate in this early translational study aimed at developing a novel treatment for AD. Our broad goal is to examine the efficacy of human neural stem cells to rescue the cognitive phenotype in animal models of AD. Our studies aim to identify a clear developmental candidate and generate sufficient data to warrant Investigational New Drug (IND) enabling activity. The proposed studies represent a novel and promising strategy for treating AD, a major human disorder for which there is currently no effective therapy.
Statement of Benefit to California: 
Neurological disorders have devastating consequences for the quality of life, and among these, perhaps none is as dire as Alzheimer disease. Alzheimer disease robs individuals of their memory and cognitive abilities, such that they are no longer able to function in society or even interact with their family. Alzheimer disease is the most common cause of dementia among the elderly and the most significant and costly neurological disorder. Currently, 5.2 million individuals are afflicted with this insidious disorder, including over 588,000 in the State of California. Hence, over 10% of the nation's Alzheimer patients reside in California. Moreover, California has the dubious distinction of ranking first in terms of states with the largest number of deaths due to this disorder. Age is the major risk factor for Alzheimer disease, with 5% of the population over age 65 afflicted, with the incidence doubling every 5 years such that 40-50% of the population over age 85 is afflicted. As the elderly represent the fastest growing segment of our society, there is an urgent need to develop therapies to prevent or treat Alzheimer disease. By 2030, the number of Alzheimer patients living in California will double to over 1.1 million. All ethnic groups will be affected, although the number of Latinos and Asians living with Alzheimer will triple by 2030, and it will double among African-Americans within this timeframe. To further highlight the direness, at present, one person develops Alzheimer disease every 72 seconds, and it is estimated that by 2050, one person will develop the disease every 33 seconds! Clearly, the sheer volume of new cases will create unprecedented burdens on our healthcare system and have a major impact on our economic system. As the most populous state, California will be disproportionately affected, stretching our public finances to their limits. To illustrate the economic impact of Alzheimer disease, studies show that an estimated $8.5 billion of care were provided in one year in the state of California alone (this value does not include other economic aspects of Alzheimer disease). Therefore, it is prudent and necessary to invest resources to try and develop strategies to delay, prevent, or treat Alzheimer disease now. California has taken the national lead in conducting stem cell research. Despite this, there has not been a significant effort to utilize the power of stem cell biology for Alzheimer disease. This proposal seeks to reverse this trend, as we have assembled a world class group of investigators throughout the State of California and in [REDACTED] to tackle the most significant and critical questions that arise in translating basic research on human stem cells into a clinical application for the treatment of Alzheimer disease. This proposal is based on an extensive body of preliminary data that attest to the feasibility of further exploring human stem cells as a treatment for Alzheimer disease.
Progress Report: 
  • Over the past decade, the potential for using stem cell transplantation as a therapy to treat neurological disorders and injury has been increasingly explored in animal models. Studies from our lab have shown that neural stem cell transplantation can improve cognitive deficits in mice resulting from extensive neuronal loss and protein aggregation, both hallmarks of Alzheimer’s Disease pathology. Our results support the justification for exploring the use of human derived stem cells for the treatment of Alzheimer’s patients.
  • During the past few months, we have begun studies aimed at taking human derived stem cells from the bench top to the bed side. To identify the best possible human stem cells to use in our future studies, we have conducted comparisons between a wide array of human stem cells and a mouse neural stem cell line (the same mouse stem cells used in the studies mentioned above). Using these results, we have selected a cohort of human stem cell candidates to which we will continue to study in upcoming experiments involving our AD model mice.
  • In addition to identifying the best human stem cells to conduct further studies, we have also performed experiments to determine the optimal immune suppression regimen to use in our human stem cell engraftment studies. Similar to organ transplants in humans, we will need to administer immune suppressants to mice which receive our candidate human stem cells. Our group has identified a potential suppressant, also found to work in humans, which we will use in future studies.
  • Over the past decade, the potential for using stem cell transplantation as a therapy to treat neurological disorders and injury has been increasingly explored in animal models. Studies from our lab have shown that neural stem cell transplantation can improve cognitive deficits in mice resulting from extensive neuronal loss and protein aggregation, both hallmarks of Alzheimer’s Disease pathology. Our results support the justification for exploring the use of human derived stem cells for the treatment of Alzheimer’s patients.
  • During the past few months, we have begun studies aimed at taking human derived stem cells from the bench top to the bed side. To identify the best possible human stem cells to use in our future studies, we have conducted comparisons between a wide array of human stem cells and a mouse neural stem cell line (the same mouse stem cells used in the studies mentioned above). Using these results, we have selected a cohort of human stem cell candidates to which we will continue to study in upcoming experiments involving our AD model mice.
  • In addition to identifying the best human stem cells to conduct further studies, we have also performed experiments to determine the optimal immune suppression regimen to use in our human stem cell engraftment studies. Similar to organ transplants in humans, we will need to administer immune suppressants to mice which receive our candidate human stem cells. Our group has identified a potential suppressant, also found to work in humans, which we will use in future studies.
  • During the last reporting period the lab has made substantial advancements in determining the effects of long term human neural stem cells engraftment on pathologies associated with the advancement of Alzheimer's disease. In addition, data obtained by our lab has may provide additional insight on ways to target the immune system as a means of prolonging neural stem cell survival and effectiveness.

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