Neurological Disorders

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

Role of HLA in neural stem cell rejection using humanized mice

Funding Type: 
Transplantation Immunology
Grant Number: 
RM1-01735-B
ICOC Funds Committed: 
$1 472 634
Disease Focus: 
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
Cell Line Generation: 
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 
One of the key issues in stem cell transplant biology is solving the problem of transplant rejection. Despite over three decades of research in human embryonic stem cells, little is known about the factors governing immune system tolerance to grafts derived from these cells. In order for the promise of embryonic stem cell transplantation for treatment of diseases to be realized, focused efforts must be made to overcome this formidable hurdle. Our proposal will directly address this critically important issue by investigating the importance of matching immune system components known as human leukocyte antigens (HLA). Because mouse and human immune systems are fundamentally different, we will establish cutting-edge mouse models that have human immune systems as suitable hosts within which to conduct our stem cell brain transplant experiments. Such models rely on immunocompromised mice as recipients for human blood-derived stem cells. These mice go on to develop a human immune system, complete with HLAs, and can subsequently be used to engraft embryonic stem cell-derived brain cells that are either HLA matched or mismatched. Due to our collective expertise in the central nervous system and animal transplantation studies for Parkinson’s disease, our specific focus will be on transplanting embryonic stem cell-derived neural stem cells into brains of both healthy and Parkinson's diseased mice. We will then detect: 1) abundance of brain immune cell infiltrates, 2) production of immune molecules, and 3) numbers of brain-engrafted embryonic stem cells. Establishing this important system would allow for a predictive model of human stem cell transplant rejection based on immune system matching. We would then know how similar HLAs need to be in order to allow for acceptance stem cell grafts.
Statement of Benefit to California: 
In this project, we propose to focus on the role of the human immune system in human embryonic stem cell transplant rejection. Specifically, we aim to develop cutting-edge experimental mouse models that possess human immune systems. This will allow us to determine whether immune system match versus mismatch enables embryonic stem cell brain transplant acceptance versus rejection. Further, we will explore this key problem in stem cell transplant biology both in the context of the healthy and diseased brain. Regarding neurological disease, we will focus on neural stem cell transplants for Parkinson's disease, which is one of the most common neurodegenerative diseases, second only to Alzheimer's disease. If successful, our work will pave the way toward embryonic stem cell-based treatment for this devastating neurological disorder for Californians and others. In order to accomplish these goals, we will utilize two of the most common embryonic stem cell types, known as WiCell H1 and WiCell H9 cells. It should be noted that these particular stem cells will likely not be reauthorized for funding by the federal government due to ethical considerations. This makes our research even more important to the State of California, which would not only benefit from our work but is also in a unique position to offer funding outside of the federal government to continue studies such as these on these two important types of human embryonic stem cells.
Progress Report: 
  • For the promise of stem cell transplantation therapy to treat or cure human disease to be realized, the key problem of stem cell transplant rejection must be solved. Yet, despite over three decades of research in human embryonic stem cells, little is known about the factors involved in immune system tolerance to grafts derived from embryonic stem cells.
  • The goal of our CIRM Stem Cell Transplantation Immunology Award is to overcome this formidable hurdle by generating pre-clinical mouse models that have human immune systems. This cutting-edge model system will provide a testing platform to evaluate the importance of matching immune system components, known as human leukocyte antigens (HLAs), between the human embryonic stem (hES) cell-derived neural stem cell (NSC) graft and the patient. Because mouse and human immune systems are fundamentally different, these next-generation ‘humanized’ mice are currently the only animal models within which to conduct our stem cell brain transplant experiments. Such models rely on immunocompromised mice as recipients for human umbilical cord blood stem cells (HSCs). These mice go on to develop a human immune system, complete with HLAs, and can subsequently be used to engraft embryonic stem cell-derived brain cells that are either HLA matched or mismatched and to monitor for graft acceptance vs. rejection.
  • During the third year of CIRM funding, we have addressed two specific questions that have arisen during the completion of Specific Aim 2: 1) which component of the HLA haplotype is most important to match in order to prevent brain stem cell rejection, and 2) can we expand blood stem cells obtained from a single umbilical cord blood sample? In response to question 1, we have determined that HLA-A is expressed at significantly higher levels in NSCs than the other HLA components, which makes this HLA type the critical player in immune system acceptance-rejection. As evidence of this, ‘humanized’ mice transplanted with NSCs expressing completely mismatched HLA-A elicited an immune response. Regarding question 2, we were able to accomplish ex vivo expansion of HSCs while maintaining their ‘stem-ness’ properties, which allows us to coordinate between the birth of mouse pups and the isolation of HSCs from umbilical cord blood samples, and also to significantly increase cell numbers to generate more ‘humanized’ mice. Additionally, in collaboration with Dr. George Liu from Cedars-Sinai Medical Center, we utilized ‘humanized’ mice to successfully model another disease that has become a threat to Californians’ health: skin infection by Staphylococcus aureus. While mice are generally not susceptible to this ‘human selective’ disease, ‘humanized’ mice did respond to the infection, closely mimicking the skin lesions observed in humans.

Induction of immune tolerance after spinal grafting of human ES-derived neural precursors

Funding Type: 
Transplantation Immunology
Grant Number: 
RM1-01720
ICOC Funds Committed: 
$1 387 800
Disease Focus: 
Spinal Cord Injury
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
iPS Cell
oldStatus: 
Closed
Public Abstract: 
Previous clinical studies have shown that grafting of human fetal brain tissue into the CNS of adult recipients can be associated with long-term (more then 10 years) graft survival even after immunosuppression is terminated. These clinical data represent in part the scientific base for the CNS to be designated as an immune privilege site, i.e., immune response toward grafted cells is much less pronounced. With rapidly advancing cell sorting technologies which permit effective isolation and expansion of neuronal precursors from human embryonic stem cells, these cells are becoming an attractive source for cell replacement therapies. Accordingly, there is great need to develop drug therapies or other therapeutic manipulations which would permit an effective engraftment of such derived cells with only transient or no immunosuppression. Accordingly, the primary goal in our studies is to test engraftment of 3 different neuronal precursors cell lines of human origin once grafted into spinal cord in transiently immunosuppressed minipigs. In addition, because the degree of cell engraftment can differ if cells are grafted into injured CNS tissue, the survival of cells once grafted into previously injured spinal cord will also be tested. Second, we will test the engraftment of neuronal cells generated from pig skin cells (fibroblasts) after genetic reprogramming (i.e., inducible pluripotent stem cells, iPS). Because these cells will be transplanted back to the fibroblast donor, we expect stable and effective engraftment in the absence of immunosuppression. Jointly by testing the above technologies (transient immunosuppression and iPS-derived neural precursors), our goal is to define the optimal neuronal precursor cell line(s) as well as immunosuppressive (or no) treatment which will lead to stable and permanent engraftment of spinally transplanted cells.
Statement of Benefit to California: 
Brain or spinal cord neurodegenerative disorders, including stroke, amyotrophic lateral sclerosis, multiple sclerosis or spinal trauma, affect many Californians. In the absence of a functionally effective cure, the cost of caring for patients with such diseases is high, in addition to a major personal and family impact. Our major goal is to develop therapeutic manipulations which are well tolerated by patients and which will lead to stable survival of previously spinal cord-grafted cells generated from human embryonic stem cells. If successful, this advance can serve as a guidance tool for CNS cell replacement therapies in general as it will define the optimal immune tolerance-inducing protocols. In addition, the development of this type of therapeutic approach (pharmacological or cell-replacement based) in California will serve as an important proof of principle and stimulate the formation of businesses that seek to develop these types of therapies (providing banks of inducible pluripotent stem cells) in California with consequent economic benefit.
Progress Report: 
  • The use of autologous, induced pluripotent stem cell-derived cell lines in replacement therapies holds great promise in future clinical use. No need for immunosuppression, otherwise required to prevent transplanted cell rejection, would represent a substantial advance in the current clinical utilization of cell replacement therapies. In our recently completed studies we have found that autologous porcine iPSC-derived neural precursors (NPCs) grafted back to the donor animal spinal cord in the absence of immunosuppression was associated with a poor cell survival and extensive inflammation at cell-grafted sites. Our data raises immunological concerns on the use of autologous iPS-cell derivatives for future regenerative medicine in humans.
  • The use of autologous, induced pluripotent stem cell-derived cell lines in replacement therapies holds great promise in future clinical use. No need for immunosuppression, otherwise required to prevent transplanted cell rejection, would represent a substantial advance in the current clinical utilization of cell replacement therapies. In our recently completed studies we have found that autologous porcine iPSC-derived neural precursors (NPCs) grafted back to the donor animal spinal cord in the absence of immunosuppression was associated with a poor cell survival and extensive inflammation at cell-grafted sites. In more recent study we have determined that the same cell population of iPS-NPCs survive and mature once grafted spinally in immunosupressed pigs.The mechanism of the immunogenicity of iPS-NPCs is being currently determined.
  • The use of autologous, induced pluripotent stem cell-derived cell lines in replacement therapies holds great promise in future clinical use. No need for immunosuppression, otherwise required to prevent transplanted cell rejection, would represent a substantial advance in the current clinical utilization of cell replacement therapies. In our recently completed studies, we have found that autologous porcine iPSC-derived neural precursors (NPCs) trigger a positive T-cell mediated reaction in vitro and that this response is not present if autologous T-cells are co-cultured with autologous fibroblasts. These data show that the reprogramming step induces a potent immunogenicity and that extensive screening of clonally-derived iPS-NPCs will be needed to identify clones of autologous NPCs with acceptable immunogenicity profile. Identification of differences in gene activity in differentially derived iPS-NPCs is currently in progress.

Systemic Protein Factors as Modulators of the Aging Neurogenic Niche

Funding Type: 
Basic Biology II
Grant Number: 
RB2-01637
ICOC Funds Committed: 
$1 522 800
Disease Focus: 
Alzheimer's Disease
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
iPS Cell
oldStatus: 
Active
Public Abstract: 
Approaches to repair the injured brain or even prevent age-related neurodegeneration are in their infancy but there is growing interest in the role of neural stem cells in these conditions. Indeed, there is hope that some day stem cells can be used for the treatment of spinal cord injury, stroke, or Parkinson’s disease and stem cells are even mentioned in the public with respect to Alzheimer’s disease. To utilize stem cells for these conditions and, equally important to avoid potential adverse events in premature clinical trials, we need to understand the environment that supports and controls neural stem cell survival, proliferation, and functional integration into the brain. This “neurogenic” environment is controlled by local cues in the neurogenic niche, by cell-intrinsic factors, and by soluble factors which can act as mitogens or inhibitory factors potentially over longer distances. While some of these factors are starting to be identified very little is known why neurogenesis decreases so dramatically with age and what factors might mediate these changes. Because exercise or diet can increase stem cell activity even in old animals and lead to the formation of new neurons there is hope that neurogenesis in the aged brain could be restored to that seen in younger brains and that stem cell transplants could survive in an old brain given the right “young” environmental factors. Indeed, our preliminary data demonstrate that systemic factors circulating in the blood are potent regulators of neurogenesis. By studying how the most promising of these factors influence key aspects of the neurogenic niche in vitro and in vivo we hope to gain an understanding about the molecular interactions that support stem cell activity and the generation of new neurons in the brain. The experiments supported under this grant will help us to identify and understand the minimal signals required to regulate adult neurogenesis. These findings could be highly significant for human health and biomedical applications if they ultimately allow us to stimulate neurogenesis in a controlled way to repair, augment, or replace neural networks that are damaged or lost due to injury and degeneration.
Statement of Benefit to California: 
In California there are hundreds of thousands of elderly individuals with age-related debilitating brain injuries, ranging from stroke to Alzheimer’s and Parkinson’s disease. Approaches to repair the injured brain or even prevent age-related neurodegeneration are in their infancy but there is growing interest in the role of neural stem cells in these conditions. However, to potentially utilize such stem cells we need to understand the basic mechanisms that control their activity in the aging brain. The proposed research will start to address this problem using a novel and innovative approach and characterize protein factors in blood that regulate stem cell activity in the old brain. Such factors could be used in the future to support stem cell transplants into the brain or to increase the activity of the brain’s own stem cells.
Progress Report: 
  • We are interested in identifying soluble protein factors in blood which can either promote or inhibit stem cell activity in the brain. Through a previous aging study and the transfer of blood from young to old mice and vice versa we had identified several proteins which correlated with reduced stem cell function and neurogenesis in young mice exposed to old blood. Over the past year we studied two factors, CCL11/eotaxin and beta2-microglobulin in more detail in tissue culture and in mice. We could demonstrate that both factors administered into the systemic environment of mice reduce neurogenesis in a brain region involved in learning and memory. We have also begun to test the effect of these factors on human neural stem cells and we started experiments to try to identify protein factors which can enhance neurogenesis.
  • While age-related cognitive dysfunction and dementia in humans are clearly distinct entities and affect different brain regions, the aging brain shows the telltale molecular and cellular changes that characterize most neurodegenerative diseases. Remarkably, the aging brain remains plastic and exercise or dietary changes can increase cognitive function in humans and animals, with animal brains showing a reversal of some of the aforementioned biological changes associated with aging. We showed recently that blood-borne factors coming outside the brain can inhibit or promote adult neurogenesis in an age-dependent fashion in mice. Accordingly, exposing an old mouse to a young systemic environment or to plasma from young mice increased neurogenesis, synaptic plasticity, and improved contextual fear conditioning and spatial learning and memory. Preliminary proteomic studies show several proteins with stem cell activity increase in old “rejuvenated” mice supporting the notion that young blood may contain increased levels of beneficial factors with regenerative capacity. We believe we have identified some of these factors now and tested them on cultured mouse and human neural stem cell derived cells. Preliminary data suggest that these factors have beneficial effects and we will test whether these effects hold true in living mice.
  • Cognitive function in humans declines in essentially all domains starting around age 50-60 and neurodegeneration and Alzheimer’s disease seems to be inevitable in all but a few who survive to very old age. Mice with a fraction of the human lifespan show similar cognitive deterioration indicating that specific biological processes rather than time alone are responsible for brain aging. While age-related cognitive dysfunction and dementia in humans are clearly distinct entities the aging brain shows the telltale molecular and cellular changes that characterize most neurodegenerative diseases including synaptic loss, dysfunctional autophagy, increased inflammation, and protein aggregation. Remarkably, the aging brain remains plastic and exercise or dietary changes can increase cognitive function in humans and animals. Using heterochronic parabiosis or systemic application of plasma we showed recently that blood-borne factors present in the systemic milieu can rejuvenate brains of old mice. Accordingly, exposing an old mouse to a young systemic environment or to plasma from young mice increased neurogenesis, synaptic plasticity, and improved contextual fear conditioning and spatial learning and memory. Unbiased genome-wide transcriptome studies from our lab show that hippocampi from old “rejuvenated” mice display increased expression of a synaptic plasticity network which includes increases in c-fos, egr-1, and several ion channels. In our most recent studies, plasma from young but not old humans reduced neuroinflammation in brains of immunodeficient mice (these mice allow us to avoid an immune response against human plasma). Together, these studies lend strong support to the existence of factors with beneficial, “rejuvenating” activity in young plasma and they offer the opportunity to try to identify such factors.
  • Cognitive function in humans declines in essentially all domains starting around age 50-60 and neurodegeneration and dementia seem to be inevitable in all but a few who survive to very old age. Mice with a fraction of the human lifespan show similar cognitive deterioration indicating that specific biological processes rather than time alone are responsible for brain aging. While age-related cognitive dysfunction and dementia in humans are clearly distinct entities and affect different brain regions the aging brain shows the telltale molecular and cellular changes that characterize most neurodegenerative diseases including synaptic loss, dysfunctional autophagy, increased inflammation, and protein aggregation. Remarkably, the aging brain remains plastic and exercise or dietary changes can increase cognitive function in humans and animals, with animal brains showing a reversal of some of the aforementioned biological changes associated with aging. Using heterochronic parabiosis we showed recently that blood-borne factors present in the systemic milieu can inhibit or promote adult neurogenesis in an age-dependent fashion in mice. Accordingly, exposing an old mouse to a young systemic environment or to plasma from young mice increased neurogenesis, synaptic plasticity, and improved contextual fear conditioning and spatial learning and memory. Over the past three years we discovered that factors in blood can actively change the number of new neurons that are being generated in the brain and that local cells in areas were neurons are generated respond to cues from the blood. We have started to identify some of these factors and hope they will allow us to regulate the activity of neural stem cells in the brain and hopefully improve cognition in diseases such as Alzheimer's.

Cellular Reprogramming: Dissecting the Molecular Mechanism and Enhancing Efficiency

Funding Type: 
Basic Biology II
Grant Number: 
RB2-01628
ICOC Funds Committed: 
$1 458 000
Disease Focus: 
Neurological Disorders
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Closed
Public Abstract: 
Pluripotent stem cells have a remarkable potential to develop into virtually any cell type of the body, making them a powerful tool for the study or direct treatment of human disease. Recent demonstration that induced pluripotent stem (iPS) cells may be derived from differentiated adult cells offers unprecedented opportunities for basic biology research, regenerative medicine, disease modeling, drug discovery and toxicology. For example, using patient-derived iPS cells, one can model diseases in vitro and screen for drugs in ways never before possible, enabling the identification of promising new therapeutic candidates earlier in the drug discovery process. In addition, iPS cell derivatives represent an ideal source for autologous cell replacement therapies, as they would not be rejected upon transplantation back into the patient. While it is clear that iPS cells hold great promise for finding therapies for diseases, there are significant hurdles that need to be overcome before full clinical potential is realized. The mechanism of iPS cell derivation is largely elusive, and the process used to generate them is very inefficient and needs to be improved in significant ways. Currently, iPS cells are generated by forced expression of four molecular factors using genome-integrating viruses. This may lead to mutations and altered differentiation potential of iPS cells, as well as tumorogenesis if transplanted back into the patient. The inefficient and stochastic nature of the reprogramming process indicates that additional, as yet unidentified mechanisms may exist and contribute to iPS cell generation. Finally, increasing the efficiency of current iPS cell derivation protocols will increase the ability to generate large panels of patient-specific iPS cell lines. We propose to use a human cell-based assay to identify small molecules that can enhance the efficiency of iPS cell generation. Our strategy will allow us to identify small molecules that target events essential for derivation of iPS cells, as well as those that replace one or more of the four virally-delivered factors. We will use the identified small molecules to discover regulatory pathways and molecular targets involved in induction of pluripotency, gaining valuable insight into the mechanism of cellular reprogramming. Application of these small molecules themselves, as well as novel approaches derived from mechanism of action studies, will help overcome issues associated with viral integration and has the potential to transform personalized cell-replacement therapies as well as accelerate drug discovery based on iPS cell-derived disease models.
Statement of Benefit to California: 
California’s health care system faces significant challenges as millions of children and adults suffer from a host of incurable illnesses. It is expected that health care costs will continue to rise as California’s citizenry ages and requires treatments for age-related, chronic metabolic, cardiovascular, and neurodegenerative disorders. Both the measureable economic impact on California’s health care system and the incalculable emotional suffering of affected individuals, their families and communities, make it an imperative to develop novel therapeutic treatments to address these mounting medical and economic societal challenges. Recognizing the potential utility of novel stem cell technologies to address California’s unmet medical needs, California voters approved Proposition 71 which created the California Institute for Regenerative Medicine (CIRM), an agency that administers funds to support stem cell research that has the greatest potential for development of novel regenerative medical treatments and cures. The CIRM Basic Biology Awards II program is intended to fund studies that will lay the foundation for future stem cell-based translational and clinical advances. In keeping with this mission, our proposed research program aims to discover new methods for producing human induced pluripotent stem cells (iPS cells) on an industrial scale and in an efficient manner; and to develop a better understanding of the mechanisms underlying cellular reprogramming. As such, our research program will help accelerate the realization of the full potential of iPS cells in cell-based regenerative medicine therapies and drug discovery. Our proposed research program will benefit the State of California and its citizens in several ways. Firstly, our research program will lay the foundation for future stem cell-based clinical and translational advances to treat and manage one of California’s most pressing unmet medical needs. Secondly, execution of our research program will create new jobs in the academic, biotechnology and pharmaceutical sectors throughout California. Funding from CIRM will be expanded with additional funding from the applicant to augment achievement of the aims of this project. CIRM funding will leverage other sources of investment in this project to help ensure California’s continued future as a world leader in biomedical innovation and translational medicine for the benefit of human health. Lastly, our proposed research program will stimulate California’s economy by creating new enabling tools and technologies that can be broadly adopted across the life science industry, thus promoting development across the academic institutions and biopharmaceutical companies that create biomedical discoveries and advances. These activities will continue to strengthen California’s leadership position at the forefront of the stem cell and regenerative medical revolution of the 21st century.
Progress Report: 
  • iPS cell lines display high variability with respect to their growth properties, differentiation ability and disease phenotype manifestation; this is a major challenge for both in vitro disease modeling and drug screening, as well as cell replacement therapy. The cause for this variability is currently unknown and heterogeneity of the starting fibroblast population, composition of reprogramming factors, and viral integration into the genome have all been proposed to contribute to variability among different iPSC clones derived from the same starting population. In particular, the use of DNA viral vectors to deliver the reprogramming factors was suggested to be the key obstacle for eventual use of iPSCs in cell replacement therapies. Recently, several methods have been developed to derive integration-free iPS cells, but they mostly suffer from unacceptably low reprogramming efficiency or labor-intensive delivery of reprogramming factors.
  • The goal of this work is to produce integration-free iPS cells with high efficiency. To date, we developed a high-throughput platform to screen small molecules that enhance reprogramming in the presence of 3 transcription factors required for reprogramming of fibroblast cells - KLF4, SOX2, and OCT4. These efforts included assay development, characterization of our engineered stable cell lines expressing reprogramming factors under control of an inducible promoter, and optimization for high-throughput screening. We screened over 100,000 compounds from our small molecule library, comprising compounds with broad chemical diversity and covering multiple cellular target classes. We identified 130 hit candidates in our primary screen, however, in follow-up assays none of these compounds showed an effect comparable with that of a positive control compound. Moving forward, we plan on detailed characterization of other integration-free reprogramming methods to determine the differences between integrating vs. non-integrating methods for reprogramming fibroblasts. We will assess the quality and variability of iPS cell lines, as well as their potential and variability of differentiation and disease phenotype manifestation in integration-free iPSCs, and compare them to DNA virus-derived iPSCs. Our results should contribute to the understanding of the source of variability between iPS cells and bring us closer to reaching the ultimate goal: production of integration-free human iPS cells with high efficiency.
  • The use of stem cell technology to study neurodegenerative diseases has been a burgeoning area of research in recent years. Recent work by us and others have demonstrated that stem cell derived cortical neurons (CN) from Alzheimer's disease patients demonstrate key disease differentials when compared to CN’s derived from healthy controls. However, most of this work has been limited to the use of simple cultures of iPSC-derived cortical or motor neurons, or in some cases, co-culture of iPSC-derived neurons with primary human astrocytes. We have demonstrated that co-culturing of iPSC-derived neurons with primary fetal astrocytes facilitates the maturation of neurons (as assessed by electrophysiology) beyond what is observed in neuronal cultures alone. We have developed an astrocyte differentiation protocol from iPSC that allows for the generation of cells with gene expression, glutamate uptake capacity and kinetics, and neurotropic factor secretion consistent with primary fetal astrocytes. Importantly, these iPSC astrocytes can be directed to an anterior versus posterior (brain versus spinal cord) identity. The goal of this study is to compare the ability of iPSC-derived astrocytes to primary fetal astrocytes in their ability to facilitate the maturation of iPSC-derived neurons, in order to identify the appropriate co-culture conditions where iPSC-derived neurons reach functional maturity as assessed by neuronal markers and electrophysiological activity. Achievement of this goal would allow for further assessment of the contribution of neurons and astrocytes to specific disease processes in neurodegeneration and neuroinflammation through the ability to combine in co-culture either disease versus healthy iPSC-derived astrocytes and/or neurons to further elucidate the underlying mechanisms contributing to these disease phenotypes. These studies should facilitate the development of co-culture systems which drive neuronal development to a more mature phenotype, and improve the availability of stem cell-based model systems to better replicate in vivo physiological and pathological processes.
  • The use of stem cell technology to study neurodegenerative diseases has been a burgeoning area of research in recent years. Recent work by us and others have demonstrated that stem cell derived cortical neurons (CN) from Alzheimer's disease patients demonstrate key disease differentials when compared to CN's derived from healthy controls. However, most of this work has been limited to the use of simple cultures of iPSC-derived cortical or motor neurons, or in some cases, co-culture of iPSC-derived neurons with primary human astrocytes. We have demonstrated that co-culturing of iPSC-derived neurons with primary fetal astrocytes facilitates the maturation of neurons (as assessed by electrophysiology) beyond what is observed in neuronal cultures alone. We have developed an astrocyte differentiation protocol from iPSC that allows for the generation of cells with gene expression, glutumate uptake capacity and kinetics, and neurotropic factor secretion consistent with primary fetal astrocytes. The goal of this study is to compare the ability of iPSC-derived astrocytes to primary fetal astrocytes in their ability to facilitate the maturation of iPSC-derived neurons. Achievement of this goal would allow for further assessment of the contribution of neurons and astrocytes to specific diseases processes in neurodegeneration and neuroinflammation through the ability to combine co-culture either in disease vs. healthy iPSC-derived astrocytes and/or neurons to further elucidate the underlying mechanisms contributing to these disease phenotypes. These studies should facilitate the development of co-culture systems which drive neuronal development to a more mature phenotype, and improve the availability of stem-cell based model systems.

MGE Enhancers to Select for Interneuron Precursors Produced from Human ES Cells

Funding Type: 
Basic Biology II
Grant Number: 
RB2-01602
ICOC Funds Committed: 
$1 387 800
Disease Focus: 
Epilepsy
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 
There are now viable experimental approaches to elucidate the genetic and molecular mechanisms that underlie severe brain disorders through the generation of stem cells, called iPS cells, from the skin of patients. Scientists are now challenged to develop methods to program iPS cells to become the specific types of brain cells that are most relevant to each specific brain disease. For instance, there is evidence that defects in cortical interneurons contribute to epilepsy, autism and schizophrenia. The experiments proposed in this grant application aim to understand basic mechanisms that underlie the development of cortical interneurons. We are discovering regulatory elements (called enhancers) in the human genome that control gene expression in developing interneurons. We have three experimental Aims. In Aim 1, we will study when and where these enhancers are expressed during mouse brain development. We will concentrate on identifying enhancers that control gene expression during development of specific types of cortical interneurons, although we hope to use this approach for additional cell types. Once we identify and characterize where and when these enhancers are active, in Aim 2 we will use the enhancers as tools in human stem cells to produce specific types of cortical interneurons in the test tube. The enhancers will be used to express proteins in the stem cells that will enable us purify only those cells that have specific properties (e.g. properties of cortical interneurons). In Aim 3 we will explore whether the human brain produces cortical interneurons in the same way as the mouse brain; this information is essential to identify molecular markers on the developing interneurons that could be used for further characterization and purification of the interneurons that we care generating in Aim 2. We want to emphasize that while the experiments focus on cortical interneuron subtypes, our work has general implications for the other types of brain cells our labs study, such as cortical and striatal neurons. In sum, the basic science mechanisms that we will discover will provide novel insights into how to generate specific types of neurons that can be used to study and treat brain diseases.
Statement of Benefit to California: 
Large numbers of California residents are stricken with severe medical disorders affecting the function of their brain. These include epilepsy, Parkinson’s Disease, Alzheimer’s Disease, Huntington’s Disease, Autism and Schizophrenia. For instance, a recent report from the Center for Disease Control and Prevention [www.cdc.gov/epilepsy/] estimates that 1 out of 100 adults have epilepsy. In California, epilepsy is one of the most common disabling neurological conditions, with approximately 140,000 affected individuals. The annual cost estimates to treat epilepsy range from $12 to $16 billion in the U.S. Currenlty up to one-third of these patients are not receiving adequate treatment, and may benefit from a cell-based transplantation therapy that we are currently exploring with our work in mice. There are now viable experimental approaches to elucidate the genetic and molecular mechanisms that underlie these neuropsychiatric disorders through the generation a stem cells, called iPS cells, from the skin of patients. Scientists are now challenged to develop methods to program iPS cells to become the specific types of brain cells that are most relevant to each specific brain disease. For instance, there is evidence that defects in cortical interneurons contribute to epilepsy, autism and schizophrenia. The experiments proposed in this grant application aim to understand basic mechanisms that underlie the development of cortical interneurons. We are discovering regulatory elements (called enhancers) in the human genome that control gene expression in developing interneurons. Our experiments will help us understand fundamental mechanisms that govern development of these cells. Furthermore, we have designed experiments that harness these enhancers to drive the production of specific subtypes of these cells from human stem cells. This will open the door to making these types of neurons from iPS cells to study human disease, and potentially to the production of these neurons for transplantation into patients whose interneurons are deficient in regulating their brain function. Furthermore, the approach we describe is general and readily applicable to the generation of other brain cells. Thus, the results from these studies will provide essential and novel basic information for understanding and potentially treating severe brain disorders.
Progress Report: 
  • We have been developing new methods to identify the products of stems cells that are differentiated in tissue culture dished. We are focusing on generating a specific type of neuron - cortical interneuron. To this end, we have identified specific sequences in the human genome that drive gene expression in the immature cortical interneurons. Results from the first year of our work provide evidence that our method to use these gene expression elements is working to help us identify cortical interneurons.
  • We have identified 5 gene regulatory elements (enhancers) that can promote gene expression in a specific type of neuronal precursor and neuron. We found that these enhancers can be used to aid in the identification and isolation of these types of cells from embryonic stem cells. In other studies, our group is testing the feasibility of using these types of cells to ameliorate neurological disorders, such as epilepsy.
  • We have identified 5 gene regulatory elements (enhancers) that can promote gene expression in a specific type of neuronal precursor and neuron. We found that these enhancers can be used to aid in the identification and isolation of these types of cells from embryonic stem cells. In other studies, our group is testing the feasibility of using these types of cells to ameliorate neurological disorders.

Role of the microenvironment in human iPS and NSC fate and tumorigenesis

Funding Type: 
Basic Biology II
Grant Number: 
RB2-01496
ICOC Funds Committed: 
$1 284 921
Disease Focus: 
Spinal Cord Injury
Neurological Disorders
Collaborative Funder: 
Japan
Stem Cell Use: 
Adult Stem Cell
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 
Multipotent Neural Stem Cells (NSC) can be derived from adult central nervous system (CNS) tissue, embryonic stem cells (ESC), or iPSC and provide a partially committed cell population that has not exhibited evidence of tumorigenesis after long term CNS transplantation. Transplantation of NSC from these different sources has been shown by multiple investigators in different CNS injury and disease paradigms to promote recovery or ameliorate disease. Additionally, both {REDACTED} groups have shown that human NSCs transplanted in the subacute period after spinal cord injury promote functional recovery. While the role of the host immune response has been considered in the context of immune-rejection, predominantly regarding the T-cell response, the consequence of an ongoing inflammatory response within the context of the tissue microenvironment for cell fate, migration, and integration/efficacy has been largely overlooked. Critically, the tumorigeneis, fate, migration, and integration/repair potential of a stem cell is driven by: 1) the intrinsic properties of cell programming, e.g., the type and source of cell / means used to derive the cell, and maintenance/differentiation of the cell in vitro; and 2) the extrinsic factors the cell encounters. Variations in the intrinsic properties of the cell may affect the potential of that cell for uncontrolled proliferation or the response of the cell to extrinsic factors that it later encounters, defining its fate, migration, and integration/repair potential. The {REDACTED} group has demonstrated that iPS-derived neurospheres (iPS-NS) exhibit a surprisingly large degree of variation in tumorigenesis potential after CNS transplantation, which is correlated with tissue source as well as differentiation and NS forming capacity. Moreover, the intrinsic properties of hNSC populations derived from different cell sources have not been broadly characterized; in fact, {REDACTED} has published the first data in the field demonstrating the differences in fate and integration/repair potential between primary and secondary neurospheres generated via in vitro differentiation of mouse or human ESC and iPSC. In parallel, {REDACTED} has shown profound differences in the response of NSC derived from human tissue versus hESC to extrinsic signals. Together, these data suggest that both characterization of the intrinsic properties of NSCs derived from different sources is essential for our understanding of the basic biology of these cells. Investigation of molecules and signaling pathways directing hNSC fate choices in the injured CNS microenvironment will yield new insight into the mechanisms of fate and migration decisions in these cell populations.
Statement of Benefit to California: 
Multipotent Neural Stem Cells (NSC) can be derived from adult central nervous system (CNS) tissue, embryonic stem cells (ESC), or induced pluripotent cells (iPSC) and provide a partially committed cell population that has not exhibited evidence of tumorigenesis after long term CNS transplantation. Transplantation of NSC from these different sources has been shown by multiple investigators in different CNS injury and disease paradigms to promote recovery or ameliorate disease. Accordingly, stem cell based therapeutics such as these have the potential to treat a variety of traumatic, congenital, and acquired human conditions. However, while much progress has been made, translational research with human stem cell populations will remain limited by the progress of the fundamental understanding of the basic biology of these cells. The {REDACTED} group has pioneered understanding the critical role of timing in considering cell transplantation therapies. More recently, this group has focused on the neural induction of mouse- and human-derived iPSC and tested the potential of these cell populations for spinal cord injury treatment in animal models. {REDACTED} has established the NOD-scid mouse as a model for experimental neurotransplantation for xenograft studies, characterizing the relationship between transplant timing, engraftment outcome, cell fate, host remyelination, and functional recovery. Recently, this group has focused on how the innate inflammatory response influences cell fate and migration. In this collaborative proposal, researchers from California and Japan propose to combine their expertise to characterize and investigate some of the most fundamental aspects of the intrinsic properties of, and extrinsic factors influencing, human induced pluripotent (hiPSC) and human embryonic (hESC) stem cells, pooling knowledge and expertise in stem cell and animal model paradigms. The experiments proposed investigate the basic cellular and molecular mechanisms underlying the role of the host environment in stem cell fate regulation, and the relationship between reprogramming and tumorigenic/fate potential of hiPS-NSC in vitro and after transplantation, and key to this collaborative effort, the interface of these two aspects of basic stem cell biology. Critically, this international collaboration combines the expertise of two of the most advanced laboratories in translational stem cell biology to address several key unresolved questions in the control of cell fate, and will promote sharing of resources, data, and techniques between these labs to advance the field. Ultimately, the collaborative work proposed may permit the development of strategies to refine cellular reprogramming techniques, alter in vitro differentiation strategies, or manipulate the microenvironment to maximize the window for potential stem cell-based neurotherapeutics.
Progress Report: 
  • Multipotent Neural Stem Cells (NSC) can be derived from adult and fetal central nervous system (CNS) tissue, embryonic stem cells (ESC), or iPSC and provide a partially committed cell population that has not exhibited evidence of tumorigenesis after long term CNS transplantation. Transplantation of NSC from these different sources has been shown by multiple investigators in different CNS injury and disease paradigms to promote recovery or ameliorate disease. Additionally, both Dr. Okano and Dr. Anderson’s groups have shown that human NSCs transplanted in the subacute period after spinal cord injury promote functional recovery. While the role of the host immune response has been considered in the context of immune-rejection, predominantly regarding the T-cell response, the consequence of an ongoing inflammatory response within the context of the tissue microenvironment for cell fate, migration, and integration/efficacy has been largely overlooked. Critically, the tumorigeneis, fate, migration, and integration/repair potential of a stem cell is driven by: 1) the intrinsic properties of cell programming, e.g., the type and source of cell / means used to derive the cell, and maintenance/differentiation of the cell in vitro; and 2) the extrinsic factors the cell encounters. Variations in the intrinsic properties of the cell may affect the potential of that cell for uncontrolled proliferation or the response of the cell to extrinsic factors that it later encounters, defining its fate, migration, and integration/repair potential. The Nakamura/Okano group has demonstrated that iPS-derived neurospheres (iPS-NS) exhibit a surprisingly large degree of variation in tumorigenesis potential after CNS transplantation, which is correlated with tissue source as well as differentiation and NS forming capacity. Moreover, the intrinsic properties of hNSC populations derived from different cell sources have not been broadly characterized; in fact, Dr. Okano’s group has published the first data in the field demonstrating the differences in fate and integration/repair potential between primary and secondary neurospheres generated via in vitro differentiation of mouse or human ESC and iPSC. In parallel, Dr. Anderson’s group has shown profound differences in the response of NSC derived from human fetal tissue versus hESC to extrinsic signals. Together, these data suggest that both characterization of the intrinsic properties of NSCs derived from different sources is essential for our understanding of the basic biology of these cells. Investigation of molecules and signaling pathways directing hNSC fate choices in the injured CNS microenvironment will yield new insight into the mechanisms of fate and migration decisions in these cell populations.
  • Progress has been excellent in the first year, as has communication between the groups.
  • The Nakamura/Okada/Okano laboratory has regularly shared and updated us on these important findings and the progress of Aim 1 at Keio University via emails, live phone conferences and face-to-face meetings. The latest meeting occurred at the International Stem Cell Meeting in Toronto (ISSCR, June 2011), where safety and efficacy data of the initial screenings of numerous hiPS cell lines are shared and discussed which will have a significant impact on which cell lines we will work with under Aims 2 and 3.
  • Additionally, the Anderson laboratory took the additional step of focusing on xeno-free cells for this grant, with the goal of advancing future knowledge of utility for clinical translation based on CIRM funding. Xeno-free cells are cells that are cultured under conditions in which they are not exposed to animal proteins. Towards this goal, we have successfully transitioned multiple ESC and iPSC lines to xeno-free conditions for both maintenance, and successfully differentiated these lines to a neural stem cell lineage under parallel conditions. Moreover, by taking this step we have significantly enhanced the comparability of different cell lines for intrinsic properties and extrinsic influences, enhancing the potential impact of this work in increasing our basic understanding of stem cell biology, and how to harness it. Finally, we have conducted the first of our experiments testing the role of cell intrinsic properties in defining responses to the in vitro and in vivo microenvironment. Our data suggest that there are clear differences in intrinsic properties between cell lines, consistent with our initial hypothesis.
  • Although the role of the host immune response has been considered in the context of immune-rejection, predominantly regarding the T-cell response, the consequence of an ongoing inflammatory response within the context of the tissue microenvironment for cell fate, migration, and integration/efficacy has been largely overlooked. While classical immunosuppressants alter the T-cell response, these drugs have minimal impact on other immune cells such as neutrophils (polymorphonuclear (PMN) leukocytes) and macrophages (MACs)/microglia, which makes up a significant part of the host environment after traumatic injuries to the CNS, such as spinal cord injury (SCI). Accordingly, there is little known about the basic biology of either the host microenvironment or inflammatory microenvironment in influencing and interacting with either endogenous or transplanted stem cell populations. Understanding the molecules and signaling pathways directing hNSC fate choices in the injured CNS microenvironment is critical. hNSC derived from hiPS-NSC and hESC will be tested. We have therefore established and characterized hiPS-NSC and hES-NSC derived from multiple origins and tested the specific role of innate inflammatory cells (i.e. PMNs and macrophages) and molecules in cell fate, migration and proliferation of these hiPS-NSC and hES-NSC lines in vitro. Thus far, these data have revealed clear cell line specific intrinsic differences in response to inflammatory factors, which we will further investigated in the coming funding period both in vitro and in vivo.
  • The fate, migration, and repair potential of a stem cell is driven by a combination of intrinsic properties, such as the type, source, and maintenance/differentiation of the cell in vitro, as well as extrinsic factors the cell encounters in the in vivo environment, such as proteins related to inflammation or the growth matrix. Variations in the intrinsic properties of the cell may affect the potential of that cell for uncontrolled proliferation or the response of the cell to extrinsic factors that it encounters in its environment. We have previously shown that neural stem cells derived from human fetal tissue are highly sensitive to extrinsic inflammatory signals in vitro and in vivo. In the current studies, we sought to determine whether neural stem cell populations derived from different sources respond to the same sorts of inflammatory signals, in other words, whether these extrinsic factors affect stem cells as a general principal. Accordingly, we sought to characterize the intrinsic properties of neural stem cells derived from different sources and exposed to extrinsic inflammatory signals, including human embryonic and induced pluripotent cell, as an essential component of understanding of basic stem cell biology. We found that, in fact, all neural stem cells derived from embryonic and induced pluripotent populations responded to inflammatory signals. However, we also found that cell line intrinsic properties exert a strong degree of control, in some cases resulting in opposing consequences for cell proliferation and fate. Critically, we found that in vitro characteristics of response to extrinsic inflammatory signals were predictive for the way different cell populations behaved in vivo after transplantation. These data may offer a new opportunity to screen stem cell populations in vitro for comparability and predicted in vivo translational properties, and reveal a new and critical set of interactions between intrinsic cell programming and response to the environment.

Embryonic-Derived Neural Stem Cells for Treatment of Motor Sequelae following Sub-cortical Stroke

Funding Type: 
Disease Team Research I
Grant Number: 
DR1-01480
ICOC Funds Committed: 
$20 000 000
Disease Focus: 
Stroke
Neurological Disorders
Collaborative Funder: 
Germany
Stem Cell Use: 
Embryonic Stem Cell
Cell Line Generation: 
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 
A stroke kills brain cells by interrupting blood flow. The most common “ischemic stroke” is due to blockage in blood flow from a clot or narrowing in an artery. Brain cells deprived of oxygen can die within minutes. The loss of physical and mental functions after stroke is often permanent and includes loss of movement, or motor, control. Stroke is the number one cause of disability, the second leading cause of dementia, and the third leading cause of death in adults. Lack of movement or motor control leads to job loss and withdrawal from pre-stroke community interactions in most patients and institutionalization in up to one-third of stroke victims. The most effective treatment for stroke, thrombolytics or “clot-busters”, can be administered only within 4.5 hours of the onset of stroke. This narrow time window severely limits the number of stroke victims that may benefit from this treatment. This proposal develops a new therapy for stroke based on embryonic stem cells. Because our (and others’) laboratory research has shown that stem cells can augment the brain’s natural repair processes after stroke, these cells widen the stroke treatment opportunity by targeting the restorative or recovery phase (weeks or months after stroke instead of several hours). Embryonic stem cells can grow in a culture dish, but have the ability to produce any tissue in the body. We have developed a technique that allows us to restrict the potential of embryonic stem cells to producing cell types that are found in the brain, making them “neural stem cells”. These are more appropriate for treating stroke and may have lower potential for forming tumors. When these neural stem cells are transplanted into the brains of mice or rats one week after a stroke, the animals are able to regain strength in their limbs. Based on these findings, we propose in this grant to further develop these neural stem cells into a clinical development program for stroke in humans at the end of this grant period. This proposal develops a multidisciplinary team that will rigorously test the effectiveness of stem cell delivery in several models of stroke, while simultaneously developing processes for the precise manufacture, testing and regulatory approval of a stem cell therapy intended for human use. Each step in this process consists of definite milestones that must be achieved, and provides measurable assessment of progress toward therapy development. To accomplish this task, the team consists of stroke physician/scientists, pharmacologists, toxicologists, experts in FDA regulatory approval and key collaborations with biotechnology firms active in this area. This California-based team has a track record of close interactions and brings prior stroke clinical trial and basic science experience to the proposed translation of a stem cell therapy for stroke.
Statement of Benefit to California: 
The State of California has made a historic investment in harnessing the potential of stem cells for regenerative therapy. While initially focused on developing new stem cell technologies, CIRM has recognized that translational progress from laboratory to clinic must also be fostered, for this is ultimately how Californians will benefit from their investment. Our focus on developing a neuro-restorative therapy for treatment of motor sequelae following sub-cortical stroke contains several benefits to California. The foremost benefit will be the development of a novel form of therapy for a major medical burden: The estimated economic burden for stroke exceeds $56.8 billion per year in the US, with 55% of this amount supporting chronic care of stroke survivors (1). While the stroke incidence markedly increases in the next half-century, death rates from stroke have declined. These statistics translate into an expected large increase in disabled stroke survivors (1) that will have a significant impact on many aspects of life for the average Californian. Stroke is the third greatest cause of death, and a leading cause of disability, among Californians. Compared to the nation, California has slightly above average rates for stroke (2). Treatments that improve repair and recovery in stroke will reduce this clinical burden. The team that has been recruited for this grant is made of uniquely qualified members, some of whom were involved in the development, manufacturing and regulatory aspects of the first clinical trial for safety of neural stem cells for stroke. Thus not only is the proposed work addressing a need that affects most Californians, it will result in the ability to initiate clinical studies of stem cells for stroke recovery from a consortium of academic and biotechnology groups in California. 1. Carmichael, ST. (2008) Themes and strategies for studying the biology of stroke recovery in the poststroke epoch. Stroke 39(4):1380-8. 2. Reynen DJ, Kamigaki AS, Pheatt N, Chaput LA. The Burden of Cardiovascular Disease in California: A Report of the California Heart Disease and Stroke Prevention Program. Sacramento, CA: California Department of Public Health, 2007.
Progress Report: 
  • A stroke kills brain cells by interrupting blood flow. The most common “ischemic stroke” is due to blockage in blood flow from a clot or narrowing in an artery. Brain cells deprived of oxygen can die within minutes. The loss of physical and mental functions after stroke is often permanent and includes loss of movement, or motor, control. Stroke is the number one cause of disability, the second leading cause of dementia, and the third leading cause of death in adults. Lack of movement or motor control leads to job loss and withdrawal from pre-stroke community interactions in most patients and institutionalization in up to one-third of stroke victims. The most effective treatment for stroke, thrombolytics or “clot-busters”, can be administered only within 4.5 hours of the onset of stroke. This narrow time window severely limits the number of stroke victims that may benefit from this treatment. This proposal develops a new therapy for stroke based on embryonic stem cells. Because our (and others’) laboratory research has shown that stem cells can augment the brain’s natural repair processes after stroke, these cells widen the stroke treatment opportunity by targeting the restorative or recovery phase (weeks or months after stroke instead of several hours).
  • Embryonic stem cells can grow in a culture dish, but have the ability to produce any tissue in the body. We have developed a technique that allows us to restrict the potential of embryonic stem cells to producing cell types that are found in the brain, making them “neural stem cells”. These are more appropriate for treating stroke and may have lower potential for forming tumors. When these neural stem cells are transplanted into the brains of mice or rats one week after a stroke, the animals are able to regain strength in their limbs. Based on these findings, we propose in this grant to further develop these neural stem cells into a clinical development program for stroke in humans at the end of this grant period.
  • A multidisciplinary team is working rigorously to test the effectiveness of stem cell delivery in several models of stroke, while simultaneously developing processes for the precise manufacture, testing and regulatory approval of a stem cell therapy intended for human use. Each step in this process consists of definite milestones that are being achieved, providing measurable assessment of progress toward therapy development. To accomplish this task, the team consists of stroke physician/scientists, pharmacologists, toxicologists, experts in FDA regulatory approval and key collaborations with a biotechnology manufacturer active in this area. This California-based team has a track record of close interactions and brings prior stroke clinical trial and basic science experience to the proposed translation of a stem cell therapy for stroke.
  • In the first year of this program, the cells have been translated from an encouraging research level to a product which can be manufactured under conditions suitable for human administration. This has included optimization of the production process, development of reliable tests to confirm cell identity and function, and characterization of the cells utilizing these tests. In animal models in two additional laboratories , improvement in motor function following stroke has been confirmed. The method of administration has also been carefully studied. It has been determined that the cells will be administered around the area of stroke injury rather than directly into the middle of the stroke area. These results encourage the translation of this product from research into clinical trials for the treatment of motor deficit following stroke.
  • A stroke kills brain cells by interrupting blood flow. The most common “ischemic stroke” is due to blockage in blood flow from a clot or narrowing in an artery. Brain cells deprived of oxygen can die within minutes. The loss of physical and mental functions after stroke is often permanent and includes loss of movement, or motor, control. Stroke is the number one cause of disability, the second leading cause of dementia, and the third leading cause of death in adults. Lack of movement or motor control leads to job loss and withdrawal from pre-stroke community interactions in most patients and institutionalization in up to one-third of stroke victims. The most effective treatment for stroke, thrombolytics or “clot-busters”, can be administered only within 4.5 hours of the onset of stroke. This narrow time window severely limits the number of stroke victims that may benefit from this treatment. This proposal develops a new therapy for stroke based on embryonic stem cells. Because our (and others’) laboratory research has shown that stem cells can augment the brain’s natural repair processes after stroke, these cells widen the stroke treatment opportunity by targeting the restorative or recovery phase (weeks or months after stroke instead of several hours).
  • Embryonic stem cells can grow in a culture dish, but have the ability to produce any tissue in the body. We have developed a technique that allows us to restrict the potential of embryonic stem cells to producing cell types that are found in the brain, making them “neural stem cells”. These are more appropriate for treating stroke and may have lower potential for forming tumors. When these neural stem cells are transplanted into the brains of mice or rats one week after a stroke, the animals are able to regain strength in their limbs. Based on these findings, we propose in this grant to further develop these neural stem cells into a clinical development program for stroke in humans at the end
  • of this grant period.
  • A multidisciplinary team is working rigorously to test the effectiveness of stem cell delivery in several models of stroke, while simultaneously developing processes for the precise manufacture, testing and regulatory approval of a stem cell therapy intended for human use. Each step in this process consists
  • of definite milestones that are being achieved, providing measurable assessment of progress toward therapy development. To accomplish this task, the team consists of stroke physician/scientists, pharmacologists, toxicologists, experts in FDA regulatory approval and key collaborations with a biotechnology manufacturer active in this area. This California-based team has a track record of close interactions and brings prior stroke clinical trial and basic science experience to the proposed translation of a stem cell therapy for stroke.
  • A stroke kills brain cells by interrupting blood flow. The most common “ischemic stroke” is due to blockage in blood flow from a clot or narrowing in an artery. Brain cells deprived of oxygen can die within minutes. The loss of physical and mental functions after stroke is often permanent and includes loss of movement, or motor control. Stroke is the number one cause of disability, the second leading cause of dementia, and the third leading cause of death in adults. Lack of movement or motor control leads to job loss and withdrawal from pre-stroke community interactions in most patients and institutionalization in up to one-third of stroke victims. The most effective treatment for stroke, thrombolytics or “clot-busters”, can be administered only within 4.5 hours of the onset of stroke. This narrow time window severely limits the number of stroke victims that may benefit from this treatment. This proposal develops a new therapy for stroke based on embryonic stem cells. Because our (and others’) laboratory research has shown that stem cells can augment the brain’s natural repair processes after stroke, these cells widen the stroke treatment opportunity by targeting the restorative or recovery phase (weeks or months after stroke instead of several hours).
  • Embryonic stem cells can grow in a culture dish, but have the ability to produce any tissue in the body. We have developed a technique that allows us to restrict the potential of embryonic stem cells to producing cell types that are found in the brain, making them “neural stem cells”. These are more appropriate for treating stroke and may have lower potential for forming tumors. When these neural stem cells are transplanted into the brains of mice or rats one week after a stroke, the animals are able to regain strength in their limbs. Based on these findings this grant is supporting conduct of IND-enabling work to initiate a clinical development program for stroke in humans by the end of this grant period.
  • A multidisciplinary team is working rigorously to test the effectiveness of stem cell delivery in several models of stroke, while enabling precise manufacture, testing and regulatory clearance of a first in human clinical trial. Defined milestones are being achieved, providing measurable assessment of progress toward therapy development. Definitive manufacturing and pharmacology studies are underway and regulatory filings are in progress. The team consists of stroke physician/scientists, pharmacologists, toxicologists, experts in FDA regulatory and key collaborations with a biotechnology manufacturer active in this area. This California-based team has a track record of close interactions and brings prior stroke clinical trial and basic science experience to the proposed translation of a stem cell therapy for stroke.
  • A stroke kills brain cells by interrupting blood flow. The most common 'ischemic stroke' is due to blockage in blood flow from a clot or narrowing in an artery. Brain cells deprived of oxygen can die within minutes. The loss of physical and mental functions after stroke is often permanent and includes loss of movement, or motor, control. Stroke is the number one cause of disability, the second leading cause of dementia, and the third leading cause of death in adults. Lack of movement or motor control leads to job loss and withdrawal from pre-stroke community interactions in most patients and institutionalization in up to one-third of stroke victims. The most effective treatment for stroke, thrombolytics or 'clot-busters', can be administered only within 4.5 hours of the onset of stroke. This narrow time window severely limits the number of stroke victims that may benefit from this treatment. This proposal develops a new therapy for stroke based on embryonic stem cells. Because our (and others') laboratory research has shown that stem cells can augment the brain's natural repair processes after stroke, these cells widen the stroke treatment opportunity by targeting the restorative or recovery phase (weeks or months after stroke instead of several hours).
  • Embryonic stem cells can grow in a culture dish, but have the ability to produce any tissue in the body. We have developed a technique that allows us to restrict the potential of embryonic stem cells to producing cell types that are found in the brain, making them 'neural stem cells'. These are more appropriate for treating stroke and may have lower potential for forming tumors. When these neural stem cells are transplanted into the brains of mice or rats one week after a stroke, the animals are able to regain strength in their limbs. Based on these findings this grant is supporting conduct of IND-enabling work to initiate a clinical development program for stroke in humans by the end of this grant period.
  • A multidisciplinary team is working to test the effectiveness of stem cell delivery in several models of stroke, while enabling precise manufacture, testing and regulatory clearance of a first in human clinical trial. Defined milestones are being achieved, providing measurable assessment of progress toward therapy development. Definitive manufacturing and pharmacology studies are underway and regulatory filings are in progress. The team consists of stroke physicians/scientists, pharmacologists, toxicologists, experts in FDA regulatory and key collaborations with a biotechnology manufacturer active in this area. This California-based team has a track record of close interactions and brings prior stroke clinical trial and basic science experience to the proposed translation of a stem cell therapy for stroke.

Molecular Characterization of hESC and hIPSC-Derived Spinal Motor Neurons

Funding Type: 
Basic Biology I
Grant Number: 
RB1-01367
ICOC Funds Committed: 
$1 363 262
Disease Focus: 
Amyotrophic Lateral Sclerosis
Neurological Disorders
Spinal Muscular Atrophy
Spinal Cord Injury
Genetic Disorder
Pediatrics
Stem Cell Use: 
Embryonic Stem Cell
iPS Cell
oldStatus: 
Active
Public Abstract: 
One of the main objectives of stem cell biology is to create physiologically relevant cell types that can be used to either facilitate the study of or directly treat human disease. Tremendous progress towards these goals has been made in the area of motor neuron disease and spinal cord injury through the findings that motor neurons can be generated from human embryonic stem cells and induced pluripotent stem cells. These advances have made possible the creation of motor neurons from patients afflicted with neurodegenerative diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy that can be studied in the laboratory to determine the root causes of these diseases. In addition, stem cell-derived motor neurons could potentially serve as replacement cells that could be introduced into the spinal cord to recover motor functions in these patients, as well as those suffering from spinal cord injuries. A major assumption, however, is that human embryonic and induced pluripotent cell-derived motor neurons are identical to their normal counterparts. Despite its relevance, few studies of human motor neuron development have been carried out, and little information on the genetic and functional similarities between stem cell- and embryo-derived motor neurons has been obtained. The proposed research will provide important new insights into the profile of human motor neurons that must be recapitulated by stem cell studies. This approach is critical given that most of our knowledge on human motor neuron development is based on animal models. In addition, work with mouse embryonic stem cell-derived motor neurons has revealed limitations in the motor neuron subtypes that can be generated in culture, something others and we have also observed in human embryonic and induced pluripotent stem cell-derived motor neurons. The differences between embryo and stem cell-derived motor neurons are currently unknown, though our preliminary studies suggest that this deficiency may result from the inability of stem cell-derived motor neurons to express key regulators of motor neuron development. We will directly test this hypothesis by examining whether artificially expressing some of these important motor neuron fate determinants can alter the classes of motor neurons formed in culture and thereby broaden their innervation potential. Since most motor neuron diseases tend to affect certain motor neuron populations more than others, and that the pattern of motor innervation is highly specific to the type of cells formed, these studies will significantly advance our understanding of how the full repertoire of motor neuron subtypes may be created from stem cells to build disease models and generate therapeutically beneficial cells.
Statement of Benefit to California: 
Neurological diseases are among the most debilitating medical conditions that affect millions of Californians each year, and many more worldwide. Few effective treatments for these diseases currently exist, in part because we know very little about the mechanisms underlying these conditions. Through the use of human embryonic stem cell and induced pluripotent stem cell technologies, it is now possible to create neurons from patients suffering from a variety of neurological disorders that can serve as the basis for cell culture-based models to study disease pathologies in an experimentally accessible setting. Our proposed research seeks to develop the means to form different classes of neurons, confirm their physiological identities, and establish a system for studying their neurological activity in a cell culture setting. The generation of these models will constitute an important step towards understanding the basis of neurological illnesses and developing a platform for the discovery of drugs that can alter disease progression and improve the productivity and quality of life for many Californians. Moreover, progress in this field will help solidify the leadership role of California in bringing stem cell research to the clinic, and stimulate the future growth of the biotechnology and pharmaceutical industries within the state.
Progress Report: 
  • The main goals of this project are to evaluate the similarities and differences between human stem cell-derived spinal motor neurons and their fetal counterparts, and to refine the techniques used to make these cells to facilitate motor neuron disease research and create therapeutically beneficial cells. In the first year of this project, we have confirmed that motor neuron generated from stem cells exhibit many molecular and physiological changes over time that closely mirror the formation of motor neurons during normal human development. There are some subtle differences, however, and our ongoing work will explore whether these discrepancies have any functional relevance. In carrying out these experiments, we also discovered new techniques by which we can create more diverse populations of motor neurons that better match the complexity seen in the spinal cord. Lastly, we have made significant progress in developing experimental assays to study the connections formed between stem cell-derived motor neurons and their muscle targets. We anticipate that these assays will serve as a valuable platform for modeling the pathology of human motor neuron diseases.
  • The main goals of this project are: 1) to evaluate the similarities and differences between human stem cell-derived spinal motor neurons and their fetal counterparts, and 2) to refine the techniques used to make these cells to facilitate motor neuron disease research and create therapeutically beneficial cells. In the second year of this project, we have documented that the initial stages of motor neuron development in stem cell cultures are very similar to the process of motor neuron formation during fetal development. However, stem cell-derived motor neurons appear to be more homogeneous than their fetal counterparts and lack several defining characteristics of mature cells. We are currently investigating the basis of these differences and whether there are any consequences on the function of the stem cell-derived neurons. We have also developed methods for evaluating the communication of stem cell-derived motor neurons with muscle cells. We anticipate that this assay platform will be valuable for modeling the pathology of neurodegenerative diseases that affect motor function. Lastly, we have obtained evidence that the forced expression of genes associated with specific motor neuron groups can strongly influence their trajectory and rate of motor axon growth, and improve innervation of limb muscles.
  • The main goals of our project are: 1) to evaluate the similarities and differences between human stem cell-derived spinal motor neurons and their fetal counterparts, and 2) to refine the techniques used to make these cells to facilitate motor neuron disease research and create therapeutically beneficial cells. In the third year of this project, we have assembled a nearly complete documentation of the developmental progression of human stem cell-derived motor neurons in cell culture compared to that seen in normal fetal development. From this analysis we conclude that the process of forming motor neurons in the culture setting faithfully replicates many aspects of their formation in the intact spinal cord. However, the types of motor neurons that are formed in stem cell cultures are more limited in their subtype diversity, which has implications for the utility of these cells as therapeutic agents and models to investigate disease mechanism. We have nevertheless found that we can extend the diversity of stem cell derived motor neurons by programming the cells to express specific proteins that promote the formation of different motor neuron subtypes. These findings suggest a general strategy for creating different functional classes of motor neurons for therapeutic uses and research applications. Lastly, we have developed two simple cell culture systems to measure the communication between motor neurons and muscle cells. Breakdown in this communication is thought to underlie many motor neuron diseases, and we anticipate that this platform will provide a means for studying the underlying pathology of these diseases, and facilitate the discovery of novel therapeutic agents.
  • The main goals of our project are: 1) to evaluate the similarities and differences between human stem cell-derived spinal motor neurons and their fetal counterparts, and 2) to refine the techniques used to make these cells to facilitate motor neuron disease research and create therapeutically beneficial cells. In the final period of this project, we have completed our documentation of the developmental progression of human stem cell-derived motor neurons in cell culture compared to that seen in normal fetal development. From this analysis we conclude that the process of forming motor neurons in the culture setting faithfully replicates many aspects of their formation in the intact spinal cord. However, the types of motor neurons that are formed in stem cell cultures are more limited in their subtype diversity, which has implications for the utility of these cells as therapeutic agents and models to investigate disease mechanism. We have nevertheless found that we can extend the diversity of stem cell derived motor neurons by programming the cells to express specific proteins that promote the formation of different motor neuron subtypes. These findings suggest a general strategy for creating different functional classes of motor neurons for therapeutic uses and research applications. Lastly, we have developed a novel cell culture system to measure the communication between motor neurons and muscle cells. Breakdown in this communication is thought to underlie many motor neuron diseases, and we anticipate that this platform will provide a means for studying the underlying pathology of these diseases, and facilitate the discovery of novel therapeutic agents.

Identification and characterization of human ES-derived DA neuronal subtypes

Funding Type: 
Basic Biology I
Grant Number: 
RB1-01358
ICOC Funds Committed: 
$1 407 076
Disease Focus: 
Parkinson's Disease
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 
Parkinson’s disease (PD) is a neurodegenerative movement disorder that affects 1 in 100 people over the age of 60, one million people in the US and six million worldwide. Patients show a resting tremor, slowness of movement (bradykinesia), postural instability and rigidity. Parkinson's disease results primarily from the loss of neurons deep in the middle part of the brain (the midbrain), in particular neurons that produce dopamine (referred to as “dopaminergic”). There are actually two groups of midbrain dopaminergic (DA) neurons, and only one, those in the substantia nigra (SN) are highly susceptible to degeneration in Parkinson’s patients. There is a relative sparing of the second group and these are called ventral tegmental area (VTA) dopaminergic neurons. These two groups of neurons reside in different regions of the adult ventral midbrain and importantly, they deliver dopamine to their downstream neuronal targets in different ways. SN neurons deliver dopamine in small rapid squirts, like a sprinkler, whereas VTA neurons have a tap that provides a continuous stream of dopamine. A major therapeutic strategy for Parkinsons’ patients is to produce DA neurons from human embryonic stem cells for use in transplantation therapy. However early human trials were disappointing, since a number of patients with grafts of human fetal neurons developed additional, highly undesirable motor dyskinesias. Why this occurred is not known, but one possibility is that the transplant mixture, which contained both SN and VTA DA neurons, provided too much or unregulated amounts of DA (from the VTA neurons), overloading or confusing the target region in the brain that usually receives dopamine from SN neurons in small, regular quantities. Future human trials will likely utilize DA neurons that have been made from human embryonic stem cells (hES). Since stem cells have the potential to develop into any type of cell in the body, these considerations suggest that we should devise a way to specifically produce SN neurons and not VTA neurons from stem cells for use in transplantation. However, although we can produce dopaminergic neurons from hES cells, to date the scientific community cannot distinguish SN from VTA neurons outside of their normal brain environment and therefore has no ability to produce one selectively and not the other. We do know, however, that these two populations of neurons normally form connections with different regions in the brain, and we propose to use this fact to identify molecular markers that distinguish SN from VTA neurons and to determine optimal conditions for the differentiation of hES to SN DA neurons, at the expense of VTA DA neurons. Our studies have the potential to significantly impact transplantation therapy by enabling the production of SN over VTA neurons from hES cells, and to generate hypotheses about molecules that might be useful for coaxing SN DA neurons to form appropriate connections within the transplanted brain.
Statement of Benefit to California: 
The goal of our work is to further optimize our ability to turn undifferentiated human stem cells into differentiated neurons that the brain can use as replacement for neurons damaged by disease. We focus on Parkinson’s disease, a neurodegenerative disease that afflicts 4-6 million people worldwide in all geographical locations, but which is more common in rural farm communities compared to urban areas, a criteria important for California's large farming population. In Parkinson’s patients, a small, well-defined subset of neurons, the midbrain dopaminergic neurons have died, and one therapeutic strategy is to transplant healthy replacement neurons to the patient. Our work will further our understanding of the biology of these neurons in normal animals. This will allow us to refine the process of turning human embryonic stem cells onto biologically active dopaminergic neurons that can be used in transplantation therapy. Our work will be of benefit to all Parkinson's patients including afflicted Californians. Further, this project will utilize California goods and services whenever possible.
Progress Report: 
  • Parkinson's disease results primarily from the loss of neurons deep in the middle part of the brain (the midbrain), in particular neurons that produce dopamine (referred to as “dopaminergic”). In this region of the midbrain there are actually two different groups of dopaminergic (DA) neurons, and only one of them, the neurons of the substantia nigra (SN) are highly susceptible to degeneration in patients with PD. There is a relative sparing of the second group of midbrain dopaminergic neurons, called the ventral tegmental area (VTA) dopaminergic neurons. These two groups of neurons reside close to each other in the brain and both make dopamine. They are virtually indistinguishable except for one major functional difference—they release dopamine, the transmitter that is lost in Parkinson’s patients, to their downstream neuronal targets in different ways. SN neurons deliver dopamine in small rapid squirts, like a sprinkler, whereas VTA neurons have a tap that provides a continuous stream of dopamine.
  • A major therapeutic strategy for patients with PD is to make new DA neurons from human embryonic stem cells (hES). As stem cells have the potential to develop into any type of cell in the body, these considerations suggest that we should devise a way to produce SN neurons in the absence of VTA neurons from stem cells for use in transplantation. At present although we can produce dopaminergic neurons from hES cells, the scientific community cannot distinguish SN from VTA neurons in vitro due to lack of molecular markers or a bioassay, and we are therefore unable to identify culture conditions that favor the production of one over the other,
  • In addition to releasing dopamine differently, SN and VTA neurons have axons that project to different regions of the striatum. It has been shown over the last decade that specific classes of guidance cues guide axons to their particular targets. One approach we have taken has been to investigate whether differences in axon guidance receptor expression and or responses to guidance cues in vitro might provide both markers and a bioassay that will distinguish SN from VTA neurons. Over the last year we have shown that VTA and SN neurons respond differentially to Netrin-1 and express different markers associated with the guidance cue family. We now have a bioassay and markers that distinguish these two populations of neurons in vitro and in the coming year we plan to utilize this information to identify cultures conditions that favor the production of SN over VTA neurons, from hES cells.
  • Parkinson’s disease results primarily from the loss of neurons deep in the middle part of the brain (the midbrain), in particular neurons that produce dopamine (referred to as “dopaminergic”). In this region of the midbrain there are actually two different groups of dopaminergic (DA) neurons, and only one of them, the neurons of the substantia nigra (SN) are highly susceptible to degeneration in patients with PD. There is a relative sparing of the second group of midbrain dopaminergic neurons, called the ventral tegmental area (VTA) dopaminergic neurons. These two groups of neurons reside close to each other in the brain and both make dopamine. They are virtually indistinguishable except for one major functional difference—they release dopamine, the transmitter that is lost in Parkinson’s patients, to their downstream neuronal targets in different ways. SN neurons deliver dopamine in small rapid squirts, like a sprinkler, whereas VTA neurons have a tap that provides a continuous stream of dopamine. 
A major therapeutic strategy for patients with PD is to make new DA neurons from human embryonic stem cells (hES). As stem cells have the potential to develop into any type of cell in the body, these considerations suggest that we should devise a way to produce SN neurons in the absence of VTA neurons from stem cells for use in transplantation. At present although we can produce dopaminergic neurons from hES cells, the scientific community cannot distinguish SN from VTA neurons in vitro due to lack of molecular markers or a bioassay, and we are therefore unable to identify culture conditions that favor the production of one over the other, 
In addition to releasing dopamine differently, SN and VTA neurons have axons that project to different regions of the striatum. It has been shown over the last decade that specific classes of guidance cues guide axons to their particular targets. One approach we have taken has been to investigate whether differences in axon guidance receptor expression and or responses to guidance cues in vitro might provide both markers and a bioassay that will distinguish SN from VTA neurons. We showed previously that VTA and SN neurons respond differentially to Netrin-1 and express different markers associated with the guidance cue family. Also, in this year using backlabeling, laser capture and microarray analysis of SN vs VTA neurons, we have identified a number of genes expressed in on or the other population. We now have a bioassay and markers that distinguish these two populations of neurons in vitro and in the coming year we plan to utilize this information to identify cultures conditions that favor the production of SN over VTA neurons, from hES cells.
  • Parkinson's disease (PD) is a neurodegenerative movement disorder that affects more than six million people worldwide. The main symptoms of the disease result from the loss of neurons from the midbrain that produce dopamine (referred to as "dopaminergic" or DA neurons).Human embryonic stem cells (hESC) offer an exciting opportunity to treat Parkinson’s disease by transplanting hESC-derived DA neurons to replace those that have died. There are actually two groups of midbrain DA neurons in the human brain. Those from the substantia nigra (SN) are highly susceptible to degeneration in Parkinson's patients while those from the ventral tegmental area (VTA) are not. These two types of neurons have similar features but have different functions and it is important to ensure that DA neurons from hESC are the correct SN type before they are used in therapy. The primary goal of this research was to study these two neuronal types in animals and determine if the distinguishing features discovered in mice or rats can be used to more easily recognize and purify SN-type DA neurons made from hESC.
  • One of the discoveries made in this research is that SN and VTA neurons show differences in how they make connections within the brain. We have been able to identify some of the molecules that guide each neuron to connect to it appropriate target and have found that SN and VTA neurons placed in the petri dish can be distinguished from each other by their response to guidance molecules. Work in the final period of this grant has focused on testing guidance response in hESC-derived DA neurons and we have found that many of the neurons produced from hESC do show SN-like responses to guidance molecules. This discovery is being further developed as a screening tool to help guide our ongoing efforts to make increasingly pure populations of DA neurons from hESC.
  • Future human trials will likely utilize such DA neurons but since embryonic stem cells have the potential to develop into any type of cell in the body, it is important to ensure that the production methods used to make a therapeutic product for Parkinson’s disease do indeed specifically produce SN neurons. Prior to the research supported under this CIRM grant, the scientific community was not able to distinguish SN from VTA neurons outside of their normal brain environment and therefore had no ability to confirm whether a method produced one type selectively and not the other. Further refinements of the assay tools developed in our research may provide a practical means of quantifying the purity of a DA neuron preparation. This would have a significant impact transplantation therapy as well as provide useful insights into the molecular mechanisms that underlie proper connectivity and function of SN and VTA DA neurons in humans.

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