Neurological Disorders

Coding Dimension ID: 
303
Coding Dimension path name: 
Neurological Disorders
Funding Type: 
Early Translational III
Grant Number: 
TR3-05628
Investigator: 
ICOC Funds Committed: 
$4 699 569
Disease Focus: 
Spinal Cord Injury
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 

We aim to develop a novel stem cell treatment for spinal cord injury (SCI) that is substantially more potent than previous stem cell treatments. By combining grafts of neural stem cells with scaffolds placed in injury sites, we have been able to optimize graft survival and filling of the injury site. Grafted cells extend long distance connections with the injured spinal cord above and below the lesion, while the host spinal cord also sends inputs to the neural stem cell implants. As a result, new functional relays are formed across the lesion site. These result in substantially greater functional improvement than previously reported in animal studies of stem cell treatment. Work proposed in this grant will identify the optimal human neural stem cells for preclinical development. Furthermore, in an unprecedented step in spinal cord injury research, we will test this treatment in appropriate preclinical models of SCI to provide the greatest degree of validation for human translation. Successful findings could lead to clinical trials of the most potent neural stem cell approach to date.

Statement of Benefit to California: 

Spinal cord injury (SCI) affects approximately 1.2 million people in the United States, and there are more than 11,000 new injuries per year. A large number of spinal cord injured individuals live in California, generating annual State costs in the billions of dollars. This research will examine a novel stem cell treatment for SCI that could result in functional improvement, greater independence and improved life styles for injured individuals. Results of animal testing of this approach to date demonstrate far greater functional benefits than previous stem cell therapies. We will generate neural stem cells from GMP-compatible human embryonic stem cells, then test them in the most clinically relevant animal models of SCI. These studies will be performed as a multi-center collaborative effort with several academic institutions throughout California. In addition, we will leverage expertise and resources currently in use for another CIRM-funded project for ALS, thereby conserving State resources. If successful, these studies will form the basis for clinical trials in a disease of great unmet medical need, spinal cord injury. Moreover, the development of this therapy would reduce costs for clinical care while bringing novel biomedical resources to the State.

Progress Report: 
  • In the first 12 months of this project we have made important progress in the following areas:
  • 1) Identified the lead embryonic stem cell type for potential use in a translational clinical program.
  • 2) Replicated the finding that implants of ES-derived neural progenitor cells from this lead cell type extend axons out from the spinal cord lesion site in very high numbers and over very long distances.
  • 3) Begun efforts to scale this work to larger animal models of spinal cord injury.
  • Very good progress has been made in the last year on this project. We are attempting to address a great unmet medical need to develop effective therapies for human spinal cord injury (SCI). We aim to develop and optimize a pluripotent neural stem cell line for grafting to sites of spinal cord injury, and develop this line for clinical translation. Unlike other programs of stem cell therapy for SCI, we are transplanting neural stem cells directly into the injury site, in high numbers, and we observe very extensive growth of axons both into and out of the graft. The amount of axon growth in this model is substantially greater than that observed with other approaches to the injured spinal cord, including approaches currently in clinical trials. Accordingly, we believe that our approach provides a substantially greater opportunity to improve outcomes after SCI.
  • In the last year, we have identified a lead stem cell line for potential human translation, and validated its ability to engraft to the injured spinal cord. We have observed that human neural stem cells, grafted into mice and rats, exhibit a human time frame for maturation and growth: cells require at least one year to develop and mature. This knowledge is very important for planning human clinical trials.
  • Remaining work will characterize the long term safety and efficacy of these cells in rodent and large animal models of SCI.
Funding Type: 
Early Translational III
Grant Number: 
TR3-05617
Investigator: 
Type: 
PI
ICOC Funds Committed: 
$4 327 175
Disease Focus: 
Multiple Sclerosis
Neurological Disorders
Stem Cell Use: 
Adult Stem Cell
Cell Line Generation: 
Adult Stem Cell
oldStatus: 
Active
Public Abstract: 

Multiple sclerosis (MS) is an autoimmune disease in which the myelin sheath that insulates neurons is destroyed, resulting in loss of proper neuronal function. Existing treatments for MS are based on strategies that suppress the immune response. While these drugs do provide benefit by reducing relapses and delaying progression (but have significant side effects), the disease invariably progresses. We are pursuing an alternative therapy aimed at regeneration of the myelin sheath through drugs that act on an endogenous stem cell population in the central nervous system termed oligodendrocyte precursor cells (OPCs). Remission in MS is largely dependent upon OPCs migrating to sites of injury and subsequently differentiating into oligodendrocytes – the cells that synthesize myelin and are capable of neuronal repair. Previous studies indicate that in progressive MS, OPCs are abundantly present at sites of damage but fail to differentiate to oligodendrocytes. As such, drug-like molecules capable of inducing OPC differentiation should have significant potential, used alone or in combination with existing immunomodulatory agents, for the treatment of MS. The objective of this project is to identify a development candidate (DC) for the treatment of multiple sclerosis (MS) that functions by directly stimulating the differentiation of the adult stem cells required for remyelination.

Statement of Benefit to California: 

Multiple Sclerosis (MS) is a painful, neurodegenerative disease that leads to an impairment of physical and cognitive abilities. Patients with MS are often forced to stop working because their condition becomes so limiting. MS can interfere with a patient's ability to even perform simple routine daily activities, resulting in a decreased quality of life. Existing treatments for MS delay disease progression and minimize symptoms, however, the disease invariably progresses to a state of chronic demyelination. The goal of this project is to identify novel promyelinating drugs, based on differentiation of an endogenous stem cell population. Such drugs would be used in combination with existing immunosuppressive drugs to prevent disease progression and restore proper neuronal activity. More effective MS treatment strategies represent a major unmet medical need that could impact the roughly 50,000 Californians suffering from this disease. Clearly the development of a promyelinating therapeutic would have a significant impact on the well-being of Californians and reduce the negative economic impact on the state resulting from this degenerative disease.

Progress Report: 
  • Multiple sclerosis (MS) is an autoimmune disease characterized by the destruction of the myelin sheath that insulates neurons, resulting in loss of proper neuronal function. Existing treatments for MS are based exclusively on strategies that suppress the immune response. We are pursuing an alternative stem cell-based therapeutic approach aimed at enhancing regeneration of the myelin sheath. Specifically, we are focused on the identification of drug-like molecules capable of inducing oligodendrocyte precursor cell (OPC) differentiation. To date, we have identified a series approved drugs that effectively induce OPC differentiation under tissue culture conditions. Additionally, we have demonstrated that several of these drug candidates reduce MS-like symptoms in relevant rodent models of the disease. We are currently conducting detailed pharmacology experiments to determine which of the identified molecules will serve as the best candidate for future clinical development.
  • The aim of this project is to identify and characterize molecules that induce the repair of lesions in multiple sclerosis. Molecules that induce the selective differentiation of oligodendrocyte precursor cells to oligodendrocytes and thereby lead to remyelination of axons are being characterized with respect to their in vitro activity and in vivo efficacy in relevant animal models, alone and in combination with immunosuppressive drugs. This work may lead to a new regenerative therapy for multiple sclerosis that is complementary to the current immune-focused therapies.
Funding Type: 
Tools and Technologies III
Grant Number: 
RT3-07800
Investigator: 
Type: 
PI
Type: 
Co-PI
ICOC Funds Committed: 
$1 380 557
Disease Focus: 
Parkinson's Disease
Neurological Disorders
Vision Loss
Stem Cell Use: 
Embryonic Stem Cell
iPS Cell
Public Abstract: 

Cell replacement therapies (CRTs) have considerable promise for addressing unmet medical needs, including incurable neurodegerative diseases. However, several bottlenecks hinder CRTs, especially the needs for improved cell manufacturing processes and enhanced cell survival and integration after implantation. Engineering synthetic biomaterials that present biological signals to support cell expansion, differentiation, survival, and/or integration may help overcome these bottlenecks. Our prior work has successfully generated synthetic biomaterial platforms for the long-term expansion of human pluripotent stem cells (hPSCs) at large scale, efficient differentiation of hPSCs into dopaminergic progenitors and neurons for treating Parkinson’s Disease, and modulation of stem cell function to promote neuronal differentiation within the brain. We now propose to advance this work and engineer two synthetic biomaterial platforms to treat neurodegenerative disease, in particular Parkinson’s Disease and Retinitis Pigmentosa. Specifically, our central goals are to further engineer biomaterial systems for scalable hPSC differentiation into dopaminergic and photoreceptor neurons, and to engineer a second biomaterial system as a biocompatible delivery vehicle to enhance the survival and engraftment of dopaminergic and photoreceptor neurons in disease models. The resulting modular, tunable platforms will have broad implications for other cell replacement therapies to treat human disease.

Statement of Benefit to California: 

This proposal addresses critical translational bottlenecks to stem cell therapies that are identified in the RFA, including the development of fully defined, xenobiotic free cell manufacturing systems and the development of clinically relevant technologies to enhance the survival and integration of human stem cell therapies. The proposed platform technologies for expanding and differentiating pluripotent stem cells in a scaleable, reproducible, safe, and economical manner will initially be developed for treating two major neurodegenerative disorders - Parkinson’s Disease and Retinitis Pigmentosa - that affect the well-being of hundreds of thousands of Californians and Americans. In addition, the biomaterial platforms are designed to be modular, such that they can be re-tuned towards other target cells to even more broadly enable cell replacement therapies and enhance our healthcare. This work will thus strongly enhance the scientific, technological, and economic development of stem cell therapeutics in California.

Furthermore, the principal investigator has a strong record of translating basic science and engineering towards clinical development within industry, particularly within California. Finally, this collaborative project will focus research groups with many students on an important interdisciplinary project at the interface of science and engineering, thereby training future employees and contributing to the technological and economic development of California.

Funding Type: 
Early Translational IV
Grant Number: 
TR4-06693
Investigator: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$2 278 080
Disease Focus: 
Amyotrophic Lateral Sclerosis
Neurological Disorders
Stem Cell Use: 
iPS Cell
oldStatus: 
Active
Public Abstract: 

ALS is a progressive neurodegenerative disease that primarily affects motor neurons (MNs). It results in paralysis and loss of control of vital functions, such as breathing, leading to premature death. Life expectancy of ALS patients averages 2–5 years from diagnosis. About 5,600 people in the U.S. are diagnosed with ALS each year, and about 30,000 Americans have the disease. There is a clear unmet need for novel ALS therapeutics because no drug blocks the progression of ALS. This may be due to the fact that multiple proteins work together to cause the disease and therapies targeting individual toxic proteins will not prevent neurodegeneration due to other factors involved in the ALS disease process. We propose to develop a novel ALS therapy involving small molecule drugs that stimulate a natural defense system in MNs, autophagy, which will remove all of the disease-causing proteins in MNs to reduce neurodegeneration. We previously reported on a class of neuronal autophagy inducers (NAIs) and in this grant will prioritize those drugs for blocking neurodegeneration of human iPSC derived MNs from patients with familial and sporadic ALS to identify leads that will then be tested for efficacy in vivo in animal models of ALS to select a clinical candidate. Since all of our NAIs are FDA approved for treating indications other than ALS, our clinical candidate could be rapidly transitioned to testing for efficacy and safety in treating ALS patients near the end of this grant.

Statement of Benefit to California: 

Neurodegenerative diseases such as ALS as well as Alzheimer’s (AD), Parkinson’s (PD) and Huntington’s Disease (HD) are devastating to the patient and family and create a major financial burden to California (CA). These diseases are due to the buildup of toxic misfolded proteins in key neuronal populations that leads to neurodegeneration. This suggests that common mechanisms may be operating in these diseases. The drugs we are developing to treat ALS target this common mechanism, which we believe is an impairment of autophagy that prevents clearance of disease-causing proteins. Effective autophagy inducers we identify to treat ALS may turn out to be effective in treating other neurodegenerative diseases. This could have a major impact on the health care in CA. Most important in our studies is the translational impact of the use of patient iPSC-derived neurons and astrocytes to identify a new class of therapeutics to block neurodegeneration that can be quickly transitioned to testing in clinical trials for treating ALS and other CNS diseases. Future benefits to CA citizens include: 1) development of new treatments for ALS with application to other diseases such as AD, HD and PD that affect thousands of individuals in CA; 2) transfer of new technologies to the public realm with resulting IP revenues coming into the state with possible creation of new biotechnology spin-off companies and resulting job creation; and 3) reductions in extensive care-giving and medical costs.

Progress Report: 
  • ALS is a progressive neurodegenerative disease that primarily affects motor neurons (MNs). It results in paralysis and loss of control of vital functions, such as breathing, leading to premature death. Much scientific evidence indicates that ALS is due to the buildup of toxic misfolded proteins in key neuronal populations that leads to neurodegeneration. In this CIRM-funded project, we are developing drugs that can improve a cellular process called “autophagy” by which cells, including neurons, clear out built-up toxic misfolded proteins and increase their longevity. We had discovered that a series of FDA-approved drugs already on the market for other indications happen to induce autophagy in a manner that is independent of their original purpose. Our goal is to show that these FDA-approved drugs can induce autophagy and slow neurodegeneration in ALS patient-derived neurons, and to repurpose these drugs for ALS. In the last year, we have made significant progress towards testing these drugs on neurons that we derived from induced pluripotent stem cells engineered from skin cells taken from ALS patients. We have built robotic microscopes that can rapidly image ALS patient neurons that are treated with drugs in the lab and determine whether any of these “autophagy-inducing” FDA-approved drugs slowdown the rate of neurodegeneration. We have optimized large-scale methods to grow patient neurons, treat them with drugs, image them over many days, and analyze the images to measure neurodegeneration. In August 2014, we published a paper in the journal Nature Chemical Biology that showed two FDA-approved drugs can in fact induce autophagy and increase the clearing of an ALS-related protein called TDP43 in neurons. The drugs were also able to slow neurodegeneration in neurons and astrocytes derived from a familial ALS patient with an altered version of the TDP43 gene. We have now obtained stem cells from broader types of familial ALS as well as sporadic ALS patients, have made neurons from their stem cells, and have treated their stem cell-derived neurons with more than 10 autophagy-inducing drugs at varying concentrations to determine whether autophagy-inducers can slow neurodegeneration in neurons from broader forms of ALS. These neurons are currently being imaged using our robotic microscope. In addition, we have started to make astrocytes from patient stem cells and plan to test the drugs on astrocytes in the coming months.
Funding Type: 
Basic Biology IV
Grant Number: 
RB4-06093
Investigator: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$1 264 248
Disease Focus: 
Neurological Disorders
Pediatrics
Stem Cell Use: 
Adult Stem Cell
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 

White matter is the infrastructure of the brain, providing conduits for communication between neural regions. White matter continues to mature from birth until early adulthood, particularly in regions of brain critical for higher cognitive functions. However, the precise timing of white matter maturation in the various neural circuits is not well described, and the mechanisms controlling white matter developmental/maturation are poorly understood. White matter is conceptually like wires and their insulating sheath is a substance called myelin. It is clear that neural stem and precursor cells contribute significantly to white matter maturation by forming the cells that generate myelin. In the proposed experiments, we will map the precise timing of myelination in the human brain and changes in the populations of neural precursor cells that generate myelin from birth to adulthood and define mechanisms that govern the process of white matter maturation. The resulting findings about how white matter develops may provide insights for white matter regeneration to aid in therapy for diseases such as cerebral palsy, multiple sclerosis and chemotherapy-induced cognitive dysfunction.

Statement of Benefit to California: 

Diseases of white matter account for significant neurological morbidity in both children and adults in California. Understanding the cellular and molecular mechanisms that govern white matter development the may unlock clues to the regenerative potential of endogeneous stem and precursor cells in the childhood and adult brain. Although the brain continues robust white matter development throughout childhood, adolescence and young adulthood, relatively little is known about the mechanisms that orchestrate proliferation, differentiation and functional maturation of neural stem and precursor cells to generate myelin-forming oligodendrocytes during postnatal brain development. In the present proposal, we will define how white matter precursor cell populations vary with age throughout the brain and determine if and how neuronal activity instructs neural stem and precursor cell contributions to human white matter myelin maturation.

Disruption of white matter myelination is implicated in a range of neurological diseases, including cerebral palsy, multiple sclerosis, cognitive dysfunction from chemotherapy exposure, attention deficit and hyperactivity disorder (ADHD) and even psychiatric diseases such as schizophrenia. The results of these studies have the potential to elucidate clues to white matter regeneration that may benefit hundreds of thousands of Californians.

Progress Report: 
  • Formation of the insulated fiber infrastructure of the human brain (called "myelin") depends upon the function of a precursor cell type called "oligodendrocyte precursor cells (OPC)". The first Aim of this study seeks to determine how OPCs differ from each other in different regions of the brain, and over different ages. Understanding this heterogeneity is important as we explore the regenerative capacity of this class of precursor cells. We have, in the past year, isolated OPCs from various regions of the human brain from individuals at various ages and are studying the molecular characteristics of these precursor cells at the single cell level in order to define distinct OPC subpopulations. We have also begun to study the functional capabilities of OPCs isolated from different brain regions. The second Aim of this study seeks to understand how interactions between electrically active neurons and OPCs affect OPC function and myelin formation. We have found that when mouse motor cortex neurons "fire" signals in such a way as to elicit a complex motor behavior, much as would happen when one practices a motor task, OPCs within that circuit respond and myelination increases. This affects the function of that circuit in a lasting way. These results indicate that neurons and OPCs interact in important ways to modulate myelination and supports the hypothesis that OPC function may play a role in learning.
  • Sending neural impulses quickly down a long nerve fiber requires a specialized type of insulation called myelin, made by a cell called an oligodendrocyte that wraps itself around neuronal projections. Myelin-insulated nerve fibers make up the “white matter” of the brain, the vast tracts that connect one information-processing area of the brain to another. We have now shown that neuronal activity prompts oligodendrocyte precursor cell (OPC) proliferation and differentiation into myelin-forming oligodendrocytes. Neuronal activity also causes an increase in the thickness of the myelin sheaths within the active neural circuit, making signal transmission along the neural fiber more efficient. This was found to be true in both juvenile and in adult brains Metaphorically, it’s much like a system for improving traffic flow along roadways that are heavily used. And as with a transportation system, improving the routes that are most productive makes the whole system more efficient.
  • Interestingly, some parts of the neural circuit studied showed evidence of myelin-forming precursor cell response to neuronal activity, while other parts of the active circuit did not. In related work, we are making progress towards understanding how OPCs differ in various regions of the brain, examining the molecular heterogeneity of human OPCs at a single cell level.
Funding Type: 
Early Translational III
Grant Number: 
TR3-05603
Investigator: 
Type: 
PI
Type: 
Co-PI
Institution: 
Type: 
Partner-PI
ICOC Funds Committed: 
$4 799 814
Disease Focus: 
Multiple Sclerosis
Neurological Disorders
Collaborative Funder: 
Australia
Stem Cell Use: 
Embryonic Stem Cell
iPS Cell
oldStatus: 
Active
Public Abstract: 

Multiple Sclerosis (MS) is a disease of the central nervous system (CNS) caused by inflammation and loss of cells that produce myelin, which normally insulates and protects nerve cells. MS is a leading cause of neurological disability among young adults in North America. Current treatments for MS include drugs such as interferons and corticosteroids that modulate the ability of immune system cells to invade the CNS. These therapies often have unsatisfactory outcomes, with continued progression of neurologic disability over time. This is most likely due to irreversible tissue injury resulting from permanent loss of myelin and nerve destruction. The limited ability of the body to repair damaged nerve tissue highlights a critically important and unmet need for MS patients. The long-term goal of our research is to develop a stem cell-based therapy that will not only halt ongoing loss of myelin but also lead to remyelination and repair of damaged nerve tissue. Our preliminary data in animal models of human MS are very promising and suggest that this goal is possible. Research efforts will concentrate on refining techniques for production and rigorous quality control of clinically-compatible transplantable cells generated from high-quality human pluripotent stem cell lines, and to verify the therapeutic activity of these cells. We will emphasize safety and development of the most therapeutically beneficial cell type for eventual use in patients with MS.

Statement of Benefit to California: 

One in seven Americans lives in California, and these people make up the single largest health care market in the United States. The diseases and injuries that affect Californians affect the rest of the US and the world. Many of these diseases involve degeneration of healthy cells and tissues, including neuronal tissue in diseases such as Multiple Sclerosis (MS). The best estimates indicate that there are 400,000 people diagnosed with MS in the USA and 2.2 million worldwide. In California, there are approximately 160,000 people with MS – roughly half of MS patients in the US live in California. MS is a life-long, chronic disease diagnosed primarily in young adults who have a virtually normal life expectancy but suffer from progressive loss of motor and cognitive function. Consequently, the economic, social and medical costs associated with the disease are significant. Estimates place the annual cost of MS in the United States in the billions of dollars. The development of a stem cell therapy for treatment of MS patients will not only alleviate ongoing suffering but also allow people afflicted with this disease to return to work and contribute to the economic stabilization of California. Moreover, a stem cell-based therapy that will provide sustained recovery will reduce recurrence and the ever-growing cost burden to the California medical community.

Progress Report: 
  • The team has been highly productive during the first year of work on this award. A major goal of the project is to evaluate the efficacy of neural progenitor cell transplantation to promote remyelination following virus induced central nervous system damage. With intracranial infection by the virus mouse hepatitis virus (MHV), mice develop paralysis due to immune mediated destruction of cells that generate myelin. Using protocols developed in the Loring laboratory, neural precursor cells (NPC) were derived from the human embryonic stem cell line H9. Mice developing paralysis due to intracranial infection with MHV were subject to intraspinal transplantation of these NPC, resulting in significant clinical recovery beginning at 2-3 weeks following transplant. This clinical effect of NPC transplantation remained out to six months, suggesting that these NPC are effective for long-term repair following demyelination. Despite this striking recovery, these human ES cell derived NPC were rapidly rejected. Several protocols for the generation of NPC for transplantation have been characterized, with the greatest clinical impact observed for NPC cultures bearing a high level of expression of TGF beta I and TGF beta II. These findings support the hypothesis that transplanted NPC reprogram the immune system within the central nervous system (CNS), leading to the activation of endogenous NPC and other repair mechanisms. Thus, it may not be necessary to induce complete immune suppression in order to promote remyelination and CNS repair following NPC transplantation for demyelinating diseases such as multiple sclerosis.
  • The team has been highly productive during the first two years of work on this award. A major goal of the project is to evaluate the efficacy of neural progenitor cell transplantation to promote remyelination following virus induced central nervous system damage. With intracranial infection by the virus mouse hepatitis virus (MHV), mice develop paralysis due to immune mediated destruction of cells that generate myelin. Using protocols developed in the Loring laboratory, neural precursor cells (NPC) were derived from the human embryonic stem cell line H9. Mice developing paralysis due to intracranial infection with MHV were subject to intraspinal transplantation of these NPC, resulting in significant clinical recovery beginning at 2-3 weeks following transplant. This clinical effect of NPC transplantation remained out to six months, suggesting that these NPC are effective for long-term repair following demyelination. Despite this striking recovery, these human ES cell derived NPC were rapidly rejected. Several protocols for the generation of NPC for transplantation have been characterized, with the greatest clinical impact observed for NPC cultures bearing a high level of expression of TGF beta I and TGF beta II. These findings support the hypothesis that transplanted NPC reprogram the immune system within the central nervous system (CNS), leading to the activation of endogenous NPC and other repair mechanisms. Thus, it may not be necessary to induce complete immune suppression in order to promote remyelination and CNS repair following NPC transplantation for demyelinating diseases such as multiple sclerosis. In addition, the group is currently assessing the impact of NPCs in experimental autoimmune encephalomyelitis (EAE), an autoimmune model of MS. Initial results suggest that NPCs also reduce the severity of disease in this model, and studies are underway to determine the mechanism(s) by which NPCs promote clinical recovery during EAE.
Funding Type: 
Tools and Technologies II
Grant Number: 
RT2-02040
Investigator: 
Type: 
PI
ICOC Funds Committed: 
$1 933 022
Disease Focus: 
Spinal Muscular Atrophy
Neurological Disorders
Pediatrics
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
Adult Stem Cell
oldStatus: 
Active
Public Abstract: 

Spinal Muscular Atrophy (SMA) is one of the most common lethal genetic diseases in children. One in thirty five people carry a mutation in a gene called survival of motor neurons 1 (SMN1) which is responsible for this disease. If two carriers have children together they have a one in four chance of having a child with SMA. Children with Type I SMA seem fine until around 6 months of age, at which time they begin to show lack of muscular development and slowly develop a "floppy" syndrome over the next 6 months. Following this period, SMA children become less able to move and are eventually paralyzed by the disease by 3 years of age or earlier. We know that this mutation causes the death of motor neurons - which are important for making muscle cells work. Interestingly, there is a second gene which can lessen the severity of the disease process (SMN2). Children with more copies of this modifying gene have less severe symptoms and can live for longer periods of time (designated Type II, III and IV and living longer periods respectively).

There is no therapy for SMA at the current time. One of the roadblocks is that there are no human models for this disorder as it is very difficult to make the motor neurons that die in the disease in the laboratory. The researchers in the current proposal have recently created pluripotent stem cells from a patient with Type I SMA (the most severe) and shown that motor neurons grown out from the pluripotent stem cells also die in the culture dish just like they do in children. This is an important model for SMA.

The proposed research takes this model of SMA and extends it to Type II and Type III children in order to have a wider range of disease severity in the culture dish (Type IV is very rare and difficult to get samples from). It then develops new technologies to produce very large numbers of motor neurons and perform large scale analysis of their survival profiles. Finally, it will explore whether novel compounds can slow down the degeneration of motor neurons in this model which should lead to the discovery of dew drugs that then may be used to treat the disease.

Statement of Benefit to California: 

The aim of this research is to develop novel drugs to treat a lethal childhood disease - SMA. There would be three immediate benefits to the state of California and its citizens.

1. Children in California would have access to novel drugs to slow or prevent their disease.
2. SMA is a world wide disease. The institutions involved with the research would be able to generate income from any new drugs developed and the profit from this would come back to California.
3. The project will employ a number of research staff in Californian institutions

Progress Report: 
  • This year we have created a large number of new SMA lines, developed ways to differentiate them into motor neurons using high content dishes, and begun to analyze the health of the motor neurons over time. We have also submitted a new paper showing that much of the cell death seen in the dying motor neurons is due to apoptosis - a form of cell death that is treatable with specific types of drug. We are now using these new lines to begin setting up screening runs with drug libraries and should be able to start these in the new year of funding.
  • In this year we have made more induced pluripotent stem (iPSC) cell lines from Spinal Muscular Atrophy patients also using blood cells in addition to skin cells. Blood cells from patients are usually more readi;y accessible. As such, this technique can be used to make larger bank of similar cell lines. We have also rigorously tested all the iPSCs them for their quality. These lines are now available for distribution to other California researchers along with a certificate of analysis.
  • Motor neurons are a type of neuron that control muscle movement and are markedly destroyed in SMA patients. In order for these powerful iPS cells form patients to be useful for discovering new drugs for SMA it is very important that we can make motor neurons from iPSCs in large quantities of millions to billions in number. Only then will testing of thousands to millions of new drugs would be feasible in neurons from SMA patients. To this end, we have created a method for making a predecessor cell type to human motor neurons from human iPSCs in a petri dish. These predecessor cells, known as motor neuron precursor spheres (iMNPS), are grown as clumps of floating spherical balls, each containing thousands such cells that are grown in large numbers repeatedly for long periods of time. We have made these iMNPS now from many SMA patients as well as healthy humans. These spheres can be preserved for long period of time by freezing them at very low temperatures. They are then awoken at a later time making it convenient for testing large numbers of drugs.
  • Since iPSCs have the power to make any cell type in the human body, they can also be contaminated with other unwanted types of cells. Typically such a technique is very difficult to accomplish in pluripotent stem cells such as embryonic and iPSCs. Therefore, we have designed a more efficient scheme to generate iPSC lines from SMA patients that will become fluorescent color (green, red or blue) when then motor neurons are made from iPSCs. These types of cells are known as reporter cell lines. This will aid in picking out the desired cell type from patient iPSCs, in this case a motor neuron, and discard any unwanted cell types. This will enormously simplify testing of new drugs in SMA patient motor neurons.
  • Deficiency of an important protein in SMA patients is one of the key causes to the course of the disease. We have also designed an automated method for identifying new drugs in patient motor neurons that will test for correction of SMN protein levels in motor neurons.
  • In Year 3 we completed making all iPSC lines from Spinal Muscular Atrophy patients. We rigorously tested all the iPSCs for quality. These lines are now available for distribution to other California researchers along with a quality control certificate.
  • Motor neurons are a type of neuron that control muscle movement and are markedly destroyed in SMA patients. In order for these powerful iPS cells form patients to be useful for discovering new drugs for SMA it is very important that we can make motor neurons from iPSCs in billions and repeatedly. Only then will testing of thousands to millions of new drugs would be feasible in neurons from SMA patients.
  • To this end, we have created a method for making a predecessor cell type to human motor neurons from human iPSCs in a petri dish. These predecessor cells, known as motor neuron precursor spheres (iMPS), are grown as clumps of floating spherical balls, each containing thousands such cells that are grown in large numbers repeatedly for long periods of time. We have now tested our method in multiple patient cells and characterized these spheres. The iMPS have now been produced from many SMA patients as well as healthy humans. The next step we have developed is to take the iMPS to make motor neurons that are similar to those that are affected in SMA children. We have then discovered a method for creating them quickly. These aggregate spheres and spinal cord motor neurons from them can be preserved for long period of time by freezing them at very low temperatures. They are then awoken at a later time making it convenient for testing large numbers of drugs.
  • Since iPSCs have the power to make any cell type in the human body, they can also be contaminated with other unwanted types of cells. Typically such a technique is very difficult to accomplish in pluripotent stem cells such as embryonic and iPSCs. Therefore, we have designed a more efficient scheme to generate iPSC lines from SMA patients that will become fluorescent color (green, red or blue) when then motor neurons are made from iPSCs. These types of cells are known as reporter cell lines. This will aid in picking out the desired cell type from patient iPSCs, in this case a motor neuron, and discard any unwanted cell types. This will enormously simplify testing of new drugs in SMA patient motor neurons. Using new technologies that can edit, cut, copy, and paste new DNA in the stem cell genome, we are also developing ways to engineer iPS cell lines that will tag the motor neurons when they are made. This will allow us another method for making pure motor neurons and tracking them in a dish among other types of cells while they are alive.
  • Deficiency of an important SMN protein in SMA patients is one of the key causes to the course of the disease. An automated method has been developed for identifying what causes the SMA neurons to become sick and test new drugs in motor neurons. We are now gearing up to test some ~1400 known compounds on patient motor neurons to determine whether we can raise SMN protein levels in motor neurons.
  • The goal of this project has now been reached. We have developed a new screening platform using motor neurons from induced pluripotent stem cells taken from children with spinal muscular atrophy. Through this technology we have screened thousands of compounds and have shown a small sub set that active gene expression and enhance motor neuron survival in this model. These compounds will now be moved to the next stage for validation. This funding has allowed us to complete the development of this tool/technology and put us in a strong position to continue these studies and the drug development process to move interesting drugs to the market for spinal muscular atrophy.
Funding Type: 
Tools and Technologies II
Grant Number: 
RT2-01880
Investigator: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$1 619 627
Disease Focus: 
Parkinson's Disease
Neurological Disorders
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 

The objective of this study is to develop a new, optimized technology to obtain a homogenous population of midbrain dopaminergic (mDA) neurons in a culture dish through neuronal differentiation. Dopaminergic neurons of the midbrain are the main source of dopamine in the mammalian central nervous system. Their loss is associated with one of the most prominent human neurological disorders, Parkinson's disease (PD). There is no cure for PD, or good long-term therapeutics without deleterious side effects. Therefore, there is a great need for novel drugs and therapies to halt or reverse the disease.

Recent groundbreaking discoveries allow us to use adult human skin cells, transduce them with specific genes, and generate cells that exhibit virtually all characteristics of embryonic stem cells, termed induced pluripotent stem cells (iPSCs). These cell lines, when derived from PD patient skin cells, can be used as an experimental pre-clinical model to study disease mechanisms unique to PD. These cells will not only serve as an ‘authentic’ model for PD when further differentiated into the specific dopaminergic neurons, but that these cells are actually pathologically affected with PD.

All of the current protocols for directed neuronal differentiation from iPSCs are lengthy and suboptimal in terms of efficiency and reproducibility of defined cell populations. This hinders the ability to establish a robust model in-a-dish for the disease of interest, in our case PD-related neurodegeneration. We will use a new, efficient gene integration technology to induce expression of midbrain specific transcription factors in iPSC lines derived from a patient with PD and a sibling control. Forced expression of these midbrain transcription factors will direct iPSCs to differentiate into DA neurons in cell culture. We aim at achieving higher efficiency and reproducibility in generating a homogenous population of midbrain DA neurons, which will lay the foundation for successfully modeling PD and improving hit rates of future drug screening approaches. Our study could also set a milestone towards the establishment of efficient, stable, and reproducible neuronal differentiation using a technology that has proven to be safe and is therefore suitable for cell replacement therapies in human.

The absence of cellular models of Parkinson’s disease represents a major bottleneck in the scientific field of Parkinson’s disease, which, if solved, would be instantly translated into a wide range of clinical applications, including drug discovery. This is an essential avenue if we want to offer our patients a new therapeutic approach that can give them a near normal life after being diagnosed with this progressively disabling disease.

Statement of Benefit to California: 

The proposed research could lead to a robust model in-a-dish for Parkinson’s disease (PD)-related neurodegeneration. This outcome would deliver a variety of benefits to the state of California.

First, there would be a profound personal impact on patients and their families if the current inevitable decline of PD patients could be halted or reversed. This would bring great happiness and satisfaction to the tens of thousands of Californians affected directly or indirectly by PD.

Progress toward a cure for PD is also likely to accelerate the development of treatments for other degenerative disorders. The technology for PD modeling in-a-dish could be applied to other cell types such as cardiomyocytes (for heart diseases) and beta-cells (for diabetes). The impact would likely stimulate medical progress on a variety of conditions in which stem cell based drug screening and therapy could be beneficial.

An effective drug and therapy for PD would also bring economic benefits to the state. Currently, there is a huge burden of costs associated with the care of patients with long-term degenerative disorders like PD, which afflict tens of thousands of patients statewide. If the clinical condition of these patients could be improved, the cost of maintenance would be reduced, saving billions in medical costs. Many of these patients would be more able to contribute to the workforce and pay taxes.

Another benefit is the effect of novel, cutting-edge technologies developed in California on the business economy of the state. Such technologies can have a profound effect on the competitiveness of California through the formation of new manufacturing and health care delivery facilities that would employ California citizens and bring new sources of revenue to the state.

Therefore, this project has the potential to bring health and economic benefits to California that is highly desirable for the state.

Progress Report: 
  • Dopaminergic (DA) neurons of the midbrain are the main source of dopamine in the mammalian central nervous system. Their loss is associated with a prominent human neurological disorder, Parkinson's disease (PD). There is no cure for PD, nor are there any good long-term therapeutics without deleterious side effects. Therefore, there is a great need for novel therapies to halt or reverse the disease. The objective of this study is to develop a new technology to obtain a purer, more abundant population of midbrain DA neurons in a culture dish. Such cells would be useful for disease modeling, drug screening, and development of cell therapies.
  • Recent discoveries allow us to use adult human skin cells, introduce specific genes into them, and generate cells, termed induced pluripotent stem cells (iPSC), that exhibit the characteristics of embryonic stem cells. These iPSC, when derived from PD patient skin cells, can be used as an experimental model to study disease mechanisms that are unique to PD. When differentiated into DA neurons, and these cells are actually pathologically affected with PD.
  • The current methods for directed DA neuronal differentiation from iPSC are inadequate in terms of efficiency and reproducibility. This situation hinders the ability to establish a robust model for PD-related neurodegeneration. In this study, we use a new, efficient gene integration technology to induce expression of midbrain-specific genes in iPSC lines derived from a patient with PD and a normal sibling. Forced expression of these midbrain transcription factor genes directs iPSC to differentiate into DA neurons in cell culture. A purer population of midbrain DA neurons may lay the foundation for successfully modeling PD and improving hit rates in drug screening approaches.
  • The milestones for the first year of the project were to establish PD-specific iPSC lines that contain genomic “docking” sites, termed “attP” sites. In year 2, these iPSC/attP cell lines will be used to insert midbrain-specific transcription factors with high efficiency, mediated by enzymes called integrases. We previously established an improved, high-efficiency, site-specific DNA integration technology in mice. This technology combines the integrase system with newly identified, actively expressed locations in the genome and ensures efficient, uniform gene expression.
  • The PD patient-specific iPSC lines we used were PI-1754, which contains a severe mutation in the SNCA (synuclein alpha) gene, and an unaffected sibling line, PI-1761. The SNCA mutation causes dramatic clinical symptoms of PD, with early-onset progressive disease. We use a homologous recombination-based procedure to place the “docking” site, attP, at well-expressed locations in the SNCA and control iPSC lines (Aim 1.1). We also included a human embryonic stem cell line, H9, to monitor our experimental procedures. The genomic locations we chose for placement of the attP sites included a site on chromosome 22 (Chr22) and a second, backup site on chromosome 19 (Chr19). These two sites were chosen based on mouse studies, in which mouse equivalents of both locations conferred strong gene expression. In order to perform recombination, we constructed targeting vectors, each containing an attP cassette flanked by 5’ and 3’ homologous fragments corresponding to the human genomic location we want to target. For the Chr22 locus, we were able to obtain all 3 targeting constructs for the PI-1754, PI-1761 and H9 cell lines. For technical reasons, we were not able to obtain constructs for the Chr19 location Thus, we decided to focus on the Chr22 locus and move to the next step.
  • We introduced the targeting vectors into the cells and selected for positive clones by both drug selection and green fluorescent protein expression. For the H9 cells, we obtained 110 double positive clones and analyzed 98 of them. We found 8 clones that had targeted the attP site precisely to the Chr22 locus. For the PI-1761 sibling control line, we obtained 44 clones, and 1 of them had the attP site inserted at the Chr22 locus. The PI-1754 SNCA mutant line, on the other hand, grows slowly in cell culture. We are in the process of obtaining enough cells to perform the recombination experiment in that cell line.
  • In summary, we demonstrated that the experimental strategy proposed in the grant indeed worked. We were successful in obtaining iPSC lines with a “docking” site placed in a pre-selected human genomic location. These cell lines are the necessary materials that set the stage for us to fulfill the milestones of year 2.
  • Parkinson's disease (PD) is caused by the loss of dopaminergic (DA) neurons in the midbrain. These DA neurons are the main source of dopamine, an important chemical in the central nervous system. PD is a common neurological disorder, affecting 1% of those at 60 years old and 4% of those over 80. Unfortunately, there is no cure for PD, nor are there any long-term therapeutics without harmful side effects. Therefore, there is a need for new therapies to halt or reverse the disease. The goal of this study is to develop a new technology that helps us obtain a purer, more abundant population of DA neurons in a culture dish and to characterize the resulting cells. These cells will be useful for studying the disease, screening potential drugs, and developing cell therapies.
  • Due to recent discoveries, we can introduce specific genes into adult human skin cells and generate cells similar to embryonic stem cells, termed induced pluripotent stem cells (iPSC). These iPSC, when derived from PD patients, can be used as an experimental model to study disease mechanisms that are unique to PD, because when differentiated into DA neurons, these cells are actually pathologically affected with PD. We are using a PD iPSC line called PI-1754 derived from a patient with a severe mutation in the SNCA gene, which encodes alpha-synuclein. The SNCA mutation causes dramatic clinical symptoms of PD, with early-onset progressive disease. For comparison we are using a normal, unaffected sibling iPSC line PI-1761. We are also using a normal human embryonic stem cell (ESC) line H9 as the gold standard for differentiation.
  • The current methods for differentiating iPSC into DA neurons are not adequate in terms of efficiency and reliability. Our hypothesis is that forced expression of certain midbrain-specific genes called transcription factors will direct iPSC to differentiate more effectively into DA neurons in cell culture. We use transcription factors called Lmx1a, Otx2, and FoxA2, abbreviated L, O, and F. In this project, we have developed a new, efficient gene integration technology that allows us rapidly to introduce and express these transcription factor genes in various combinations, in order to test whether they stimulate the differentiation of iPSC into DA neurons.
  • In the first year of the project, we began establishing iPSC and ESC lines that contained a genomic “landing pad” site for insertion of the transcription factor genes. We carefully chose a location for placement of the genes based on previous work in mouse that suggested that a site on human chromosome 22 would provide strong and constant gene expression. We initially used ordinary homologous recombination to place the landing pad into this site. By the end of year 1 of the project, this method was successful in the normal iPSC and in the ESC, but not in the more difficult-to-grow PD iPSC. To solve this problem, in year 2 we introduced a new and more powerful recombination technology, called TALENs, and were successful in placing the landing pad in the correct position in all three of the lines, including the PD iPSC.
  • We were now in a position to insert the midbrain-specific transcription factor genes with high efficiency. For this step, we developed a new genome engineering methodology called DICE, for dual integrase cassette exchange. In this technology, we use two site-specific integrase enzymes, called phiC31 and Bxb1, to catalyze precise placement of the transcription factor genes into the desired place in the genome.
  • We constructed gene cassettes carrying all pair-wise combinations of the L, O, and F transcription factors, LO, LF, and OF, and the triple combination, LOF. We successfully demonstrated the power of this technology by rapidly generating a large set of iPSC and ESC that contained all the above combinations of transcription factors, as well as lines that contained no transcription factors, as negative controls for comparison. Two examples of each type of line for the 1754 and 1761 iPSC and the H9 ESC were chosen for differentiation and functional characterization studies. Initial results from these studies have demonstrated correct differentiation of neural stem cells and expression of the introduced transcription factor genes.
  • In summary, we were successful in obtaining ESC and iPSC lines from normal and PD patient cells that carry a landing pad in a pre-selected genomic location chosen and validated for strong gene expression. These lines are valuable reagents. We then modified these lines to add DA-associated transcription factors in four combinations. All these lines are currently undergoing differentiation studies in accordance with the year two and three timelines. During year three of the project, the correlation between expression of various transcription factors and the level of DA differentiation will be established. Furthermore, functional studies with the PD versus normal lines will be carried out.
  • The objective of this project is to develop approaches and technologies that will improve neuronal differentiation of stem cells into midbrain dopaminergic (DA) neurons. DA neurons are of central importance in the project, because they are that cells that are impaired in patients with Parkinson’s disease (PD). Current differentiation methods typically produce low yields of DA neurons. The methods also give variable results, and cell populations contain many types of cells. These impediments have hampered the study of disease mechanisms for PD, as well as other uses for the cells, such as drug screening and cell replacement therapy. Our strategy is to develop a novel method to introduce genes into the genome at a specific place, so we can rapidly add genes that might help in the differentiation of DA neurons. The genes we would like to add are called transcription factors, which are proteins involved differentiation of stem cells into DA neurons. We have placed the genes for three transcription factors into a safe, active position on human chromosome 22 in the cell lines we are studying. These cells, called pluripotent stem cells, have the potential to differentiate into almost any type of cell. We are using embryonic stem cells in our study, as well as induced pluripotent stem cells (iPSC), which are similar, but are derived from adult cells, rather than an embryo. We are using iPSC derived from a PD patient, as well as iPSC from a normal person, for comparison. By forced expression of these neuronal transcription factors, we may achieve more efficient and reproducible generation of DA neurons. The effects of expressing different combinations of the three transcription factors called Lmx1a, FoxA2, and Otx2 on DA neuronal differentiation will be evaluated in the context of embryonic stem cells (ESC) as the gold standard, as well as in iPSC derived from a PD patient with a severe mutation in alpha-synuclein and iPSC derived from a normal control. Comparative functional assays of the resulting DA neurons will complete the analysis.
  • To date, this project has created a novel technology for modifying the genome. The strategy developed out of the one that we originally proposed, but contains several innovations that make it more powerful and useful. The new methodology, called DICE for Dual Integrase Cassette Exchange, allowed us to generate “master” or recipient cell lines for ESC, normal iPSC, and PD iPSC. These recipient cell lines contain a “landing pad” placed into a newly-identified actively-expressed location on human chromosome 22 called H11 that permits robust expression of genes placed into it. We then generated a series of cell lines by "cassette exchange" at the H11 locus. In cassette exchange, the new genes we want to add take the place of the landing pad we originally put into the cells. Cassette exchange is a good way to introduce various genes into the same place in the chromosomes. We created cell lines expressing three neuronal transcription factors suspected to be involved in DA neuronal differentiation, in all pair-wise combinations, including lines with expression of all three factors, and negative control lines with no transcription factors added. This collection of modified human pluripotent stem cell lines is now being used to study neural differentiation. The modified ESC have undergone differentiation into DA neurons and are being evaluated for the effects of the different transcription factor combinations on DA neuronal differentiation. During the final year of the project, this differentiation analysis will be completed, and we will also analyze functional properties of the differentiated DA neurons, with special emphasis on disease-related features of the cells derived from PD iPSC.
  • The objective of this project is to develop technologies and approaches that will improve differentiation of stem cells into midbrain dopaminergic (DA) neurons. DA neurons are of central importance in the project, because they are the cells that are impaired in patients with Parkinson’s disease (PD). It appears that midbrain dopaminergic neurons have an enormous energy requirement, which might help explain their vulnerability to degeneration in PD. Current differentiation methods typically produce low yields of DA neurons. The methods also give variable results, and cell populations contain many types of cells. These impediments have hampered the study of disease mechanisms for PD, as well as other uses for the cells, such as drug screening and cell replacement therapy. Our strategy is to develop a novel method to introduce genes into the genome at a specific place, so we can rapidly add genes that might help in the differentiation of DA neurons. The genes we would like to add are called transcription factors, which are proteins involved in differentiation of stem cells into DA neurons. We have placed the genes for three transcription factors into a safe, active position on human chromosome 22 in the cell lines we are studying. These cells, called pluripotent stem cells, have the ability to differentiate into almost any type of cell. We are using embryonic stem cells in our study, as well as induced pluripotent stem cells (iPSC), which are similar, but are derived from adult cells, rather than an embryo. We are using iPSC derived from a PD patient, as well as iPSC from a normal person, for comparison. By forced expression of neuronal transcription factors, we may achieve more efficient and reproducible generation of DA neurons. We want to evaluate the effects of expressing different combinations of three transcription factors called Lmx1a, FoxA2, and Otx2 on DA neuronal differentiation in the context of embryonic stem cells (ESC) as the gold standard, as well as in iPSC derived from a PD patient with a severe mutation in alpha-synuclein, and in iPSC derived from a normal person without PD. Comparative functional assays of the resulting DA neurons will complete the analysis.
  • To date, this project created a novel technology for modifying the genome. The strategy developed out of the one that we originally proposed, but contains several innovations that make it more powerful and useful. The new methodology, called DICE for Dual Integrase Cassette Exchange, allowed us to generate “master” or recipient cell lines for ESC, normal iPSC, and PD iPSC. These recipient cell lines contain a “landing pad” placed into a newly-identified actively-expressed location on human chromosome 22 called H11 that permits robust expression of genes placed into it. We then generated a series of cell lines by "cassette exchange" at the H11 locus. In cassette exchange, the new genes we want to add take the place of the landing pad we originally put into the cells. Cassette exchange is a good way to introduce various genes into the same place in the chromosomes.
  • We created cell lines expressing three neuronal transcription factors suspected to be involved in DA neuronal differentiation, in all pair-wise combinations, including lines with expression of all three factors, and negative control lines with no transcription factors added. This collection of modified human pluripotent stem cell lines is being used to study neural differentiation. The modified ESC were used to form embryoid bodies, which are spherical aggregations of stem cells similar to an embryo that are favorable for producing differentiated cells. We found that the embyroid bodies underwent a rapid process of spontaneous differentiation into DA neurons. The differentiation was stimulated in the cells that expressed inserted transcription factors, and some combinations of transcription factors were better than others in bringing about DA neuronal differentiation. We obtained the best differentiation in the lines that expressed the LMX1A and OTX2 transcription factors. In continuing studies, we will analyze functional properties of the differentiated DA neurons, with special emphasis on disease-related features of the cells derived from PD iPSC.
Funding Type: 
Early Translational II
Grant Number: 
TR2-01767
Investigator: 
Type: 
PI
ICOC Funds Committed: 
$1 708 549
Disease Focus: 
Neurological Disorders
Trauma
Collaborative Funder: 
Maryland
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 

Traumatic brain injury (TBI) affects 1.4 million Americans a year; 175,000 in California. When the brain is injured, nerve cells near the site of injury die due to the initial trauma and interruption of blood flow. Secondary damage occurs as neighboring tissue is injured by the inflammatory response to the initial injury, leading to a larger area of damage. This damage happens to both neurons, the electrically active cells, and oligodendrocytes, the cell which makes the myelin insulation. A TBI patient typically loses cognitive function in one or more domains associated with the damage (e.g. attention deficits with frontal damage, or learning and memory deficits associated with temporal lobe/hippocampal damage); post-traumatic seizures are also common. Currently, no treatments have been shown to be beneficial in alleviating the cognitive problems following even a mild TBI.

Neural stem cells (NSCs) provide a cell population that is promising as a therapeutic for neurotrauma. One idea is that transplanting NSCs into an injury would provide “cell replacement”; the stem cells would differentiate into new neurons and new oligodendrocytes and fill in for lost host cells. We have successfully used “sorted“ human NSCs in rodent models of spinal cord injury, showing that hNSCs migrate, proliferate, differentiate into oligodendrocytes and neurons, integrate with the host, and restore locomotor function. Killing the NSCs abolishes functional improvements, showing that integration of hNSCs mediates recovery. Two Phase I FDA trials support the potential of using sorted hNSC for brain therapy and were partially supported by studies in my lab. NSCs may also improve outcome by helping the host tissue repair itself, or by providing trophic support for newly born neurons following injury. Recently, transplantation of rodent-derived NSCs into a model of TBI showed limited, but significant improvements in some outcome measures. These results argue for the need to develop human-derived NSCs that can be used for TBI.

We will establish and characterize multiple “sorted” and “non-sorted“ human NSC lines starting from 3 human ES lines. We will determine their neural potential in cell culture, and use the best 2 lines in an animal model of TBI, measuring learning, memory and seizure activity following TBI; then correlating these outcomes to tissue modifying effects. Ultimately, the proposed work may generate one or more human NSC lines suitable to use for TBI and/or other CNS injuries or disorders. A small reduction in the size of the injury or restoration of just some nerve fibers to their targets beyond the injury could have significant implications for a patient’s quality of life and considerable economic impact to the people of California. If successful over the 3-year grant, additional funding of this approach may enable a clinical trial within the next five years given success in the Phase I FDA approved trials of sorted hNSCs for other nervous system disorders.

Statement of Benefit to California: 

The Centers for Disease Control and Prevention estimate that traumatic brain injury (TBI) affects 1.4 million Americans every year. This equates to ~175,000 Californian’s suffering a TBI each year. Additionally, at least 5.3 million Americans currently have a long-term or a lifelong need for help to perform activities of daily living as a result of suffering a TBI previously. Forty percent of patients who are hospitalized with a TBI had at least one unmet need for services one year after their injury. One example is a need to improve their memory and problem solving skills. TBI can also cause epilepsy and increases the risk for conditions such as Alzheimer's disease, Parkinson's disease, and other brain disorders that become more prevalent with age. The combined direct medical costs and indirect costs such as lost productivity due to TBI totaled an estimated $60 billion in the United States in 2000 (when the most recent data was available). This translates to ~$7.5 billion in costs each year just to Californians.

The proposed research seeks to generate several human neural-restricted stem cell lines from ES cells. These “sorted” neural-restricted stem cell lines should have greatly reduced or no tumor forming capability, making them ideally suited for clinical use. After verifying that these lines are multipotent (e.g. they can make neurons, astrocytes and oligodendrocytes), we will test their efficacy to improve outcomes in TBI on a number of measures, including learning and memory, seizure activity, tissue sparing, preservation of host neurons, and improvements in white matter pathology. Of benefit to California is that these same outcome measures in a rodent model of TBI can also be assessed in humans with TBI, potentially speeding the translational from laboratory to clinical application.

A small reduction in the size of the injury, or restoration of just some nerve fibers to their targets beyond the injury, or moderate improvement in learning and memory post-TBI, or a reduction in the number or severity of seizures could have significant implications for a patient’s quality of life and considerable economic impact to the people of California. Additionally, the cell lines we have chosen to work with are unencumbered with IP issues that would prevent us, or others, from using these cell lines to test in other central nervous system disorders. Two of the cell lines have already been manufactured to “GMP” standards, which would speed up the translation of this work from the laboratory to the clinic. Finally, if successful, these lines would be potentially useful for treating a variety of central nervous system disorders in addition to TBI, including Alzheimer’s disease, Parkinson’s disease, stroke, autism, spinal cord injury, and/or multiple sclerosis.

Progress Report: 
  • In the first year of this Early Translation Award for traumatic brain injury (TBI), our goal was to develop the stem cells lines necessary to begin testing of stem cells in an animal model of TBI in year 2. If we are fortunate to demonstrate that the stem cell products are effective in animal models of TBI, these cells will need to be grown in a way that is acceptable to the FDA for future use in man. Xenofree means that the cells are not exposed to possible animal product contaminants (e.g. serum or blood products) and that every component that the cells were exposed to is chemically defined and can be traced to the original source.
  • First, we obtained three separate embryonic stem (ES) cell lines from Sheffield, UK and imported them to the United States. These lines where then thawed and grown in “xenofree” cell culture conditions. Many labs have had difficulty transitioning human ES cells to xenofree conditions without introducing genetic defects in the cell lines or killing the cells. We were able to work out the correct conditions for all three ES cell lines to be grown xenofree. We were also successful in converting two of the three ES lines into neural stem cells (the subtype of stem cell needed for transplanting into brain tissue). These neural stem cells (NSCs) were further purified by labeling them for a stem cell surface marker present on NSCs (called CD133) and then magnetically sorting out just the CD133 positive cells and continuing to grow them. This approach is thought to enrich the stem cell population for NSCs and eliminate any remaining non-differentiated ES cells (which have an added risk of forming tumors if injected into animals or man). We successfully “sorted” both Shef cell lines and we now have four candidate populations of sorted and unsorted Shef4 and Shef6 cells. We grew these cells in culture and tested whether they differentiated into neuronal precursor or glial precursor cells. Quantification of the type of cells they turn into after 2 weeks showed that the four cell populations were different. These differences were even more apparent when looking at the cells in a microscope. At the end of year one, we have four different populations of neural stem cells which are growing in defined xenofree conditions, are frozen down in master cell banks, and which are genetically normal. There are sufficient quantities of these human neural stem cells (hNSC) to complete the remaining aims of the ETA grant over the remaining two years.
  • In the first year we also trained staff in the surgical procedures required to produce controlled cortical impact injuries in Athymic nude rats (ATNs), a type of rat that has no immune system. These procedures were necessary because no one has ever used ATN rats to model TBI. Our goal in year two is to transplant hNSCs into rats with TBI. If the rats had a normal immune system, their bodies would detect the foreign human cells and reject them. Also, because no one has ever tested TBI in ATN rats, we needed to find out if ATN rats respond like regular rats to the injury and if they have similar, predictable deficits on the cognitive tasks we plan to use in year 2 to measure whether hNCSs improve the animal’s recovery or not. This training and these pilot tests in ATN rats were completed successfully. Finally, the hypothesis is that by “sorting” the hNSCs to be CD133 positive, we are making the stem cell population safer for transplantation. This will be tested in year 2 using a tumorigenicity assay. We worked out how to conduct these assays in year 1 using a population of ES cells known to cause tumors so that we will have a positive control to compare the hNSCs to in year 2.
  • In summary, we met all of our goals and milestones for year 1 and are poised to make good progress in year 2.
  • The goal of this project is to take three human embryonic stem cell lines (Shef3, Shef4, and Shef6), transition them to multipotent neural stem cell (hNSC) populations, sort/enrich these hNSC stem/progenitor populations, and then test these cell lines for efficacy in a rat model of controlled cortical impact (CCI) model of traumatic brain injury (TBI). Our strategy is to develop xenofree culture methods for the transition of hESC to NSCs, use magnetic activated cell sorting (MAC) for the cell surface markers CD133+/CD34- to enrich the hNSC populations for stem/progenitor cells, test these sorted vs unsorted cell lines in tumorigenicity assays, and use the best two non-tumorigenic lines in a CCI model of TBI. Efficacy will be assessed on a battery of cognitive tests, via a reduction in spontaneous seizure, and in histological outcomes.
  • At the Two Year time-point in the grant, we have (A) generated 6 hNSC populations, (B) completed short-term teratoma assays which demonstrate that none of our hNSC populations form teratomas in either of two transplantation sites (sub cutaneous into the leg or intracranially into the brain, (C) established parameters for graded contusion traumatic brain injuries in ATN rats that (D) yield long-term (≥8 weeks) deficits in both learning and memory on the Morris Water Maze. (E) We have also determined that TBI yields an altered response on a conditioned taste aversion task (neophobia) and on the elevated plus maze compared to sham controls. (F) Determined that unsorted hNSCs (both Shef4 and Shef6) do not survive long-term in uninjured brain and (G) transplanted two large cohorts of TBI injured animals with Shef6 sorted NSCs of high passage, Shef6 sorted hNSCs of low passage, sham animals, and animals with a vehicle control. These two cohorts are too large to run simultaneously, so they are being run in parallel. Animals from both cohorts will complete functional all assessments by the end of June 2013.
  • Summary: We have very promising preclinical efficacy data in a rodent model of traumatic brain injury (TBI) using stem cells as a potential therapeutic. We have found that intra-cranial transplants of Shef-6 derived human neural stem cells (hNSCs) appear to induce improvement on two different behavioral domains after long-term (>2 months) survival. Importantly, Shef-6 hNSCs did not form tumors when transplanted at high doses into naïve brain. Shef-6 hNSCs are xenofree, GMP compatible, suitable for use in man (the donor and cells were certified to be free of HIV, Hepatitis A, B, C, HTLV, EBV, CMV, and are mycoplasma free). Furthermore, Shef-6 is on the FDA embryonic stem cell registry, enabling future Federal funding of their clinical testing in man if warranted. Specifically, we have demonstrated long-term efficacy in a moderate to severe controlled cortical impact (CCI) model of TBI using Shef-6 derived hNSCs on both a cognitive task (MWM Reversal Learning) and an emotional task (Elevated Plus Maze for anxiety). This dual improvement across cognitive and emotional domains is unique to the field and supports external validity of the model. These behavioral findings need to be correlated with quantification of the total number of surviving human cells and their terminal cell fate (whether the hNSCs differentiated into neurons, oligodendrocytes, or astrocytes) to confirm efficacy. Stereological quantification is currently ongoing and very labor intensive. If the correlation between surviving cells and cognitive improvements holds up after the quantification is complete, these findings will support a future Preclinical Development Award application to CIRM. Additionally, we are the first group to couple kindling and TBI to model the critical complication of post-TBI seizures. Traditional TBI models yield seizures in less than 20% of rodents, making hNSC studies cost prohibitive. Coupling kindling with TBI ensures that all animals start with a hypersensitive neural circuit so hNSCs can be tested in a more relevant environment; we will be ready to begin this important kindling test coupled with hNSCs in the Spring of 2014. These studies have paved new ground for a field with huge economic costs, no treatments, and no GMP qualified ES based solutions on the horizon.
  • Traumatic Brain Injuries (TBI) are the leading cause of death and disability in the young population. Falls resulting in injury to the brain are also a major problem in the elderly. The rate of TBI is greater than the number of people diagnosed with brain, breast, colon, lung, and prostate cancers combined, yet nationally the US invests 95% more research dollars on cancer compared to TBI. 1.7 million new cases of TBI occur each year, at an economic cost of $60 billion. Extrapolating to California (12% of US population), there are ~210,000 new cases of TBI a year in our state, with a yearly cost that exceeds $7 billion. TBI results in permanent long-term deficits, including memory impairments and emotional disfunction, that affect both the patient and their families. There are no treatments to alleviate the long-term consequences of TBI. Yet a small reduction in damage, restoration of just some nerve fibers to their targets beyond the injury, or moderate improvement in learning, memory, or emotional outcomes could have significant implications for an individual’s quality of life. Our hypothesis was that human neural stem cells (hNCSs) might alleviate some impairments associated with TBI in a new animal model of neurotrauma. Our first goal was to grow hNSCs under cell culture conditions free from contamination of non-human products (referred to as “xenofree”), and then sort these cells based on cell surface markers known to be present in high concentrations on migratory neural stem cells (and not other byproducts of the culture conditions). Our second goal was to develop an animal model of TBI with long-lasting cognitive and emotional deficits; this animal model had to be “immuno-deficient”, or lacking a functional immune system, so that “foreign” human cells would not be rejected. Long-lasting deficits were need so that there would be a sufficient time window of dysfunction to allow the hNSCs to divide, migrate through the brain, and possibly restore function. If animals recover function too quickly on their own (as happens in some models of neurotrauma), then there would not be a large enough difference between control animals and injured animals to detect an effect of the hNSCs or not. Goal three was to test the therapeutic effects of hNSCs in this model. Finally, because a large number of people with TBI also experience seizures long after the initial injury, our forth goal was to combine “kindling” with TBI and ask whether hNSCs could alter kindling. Kindling involves implanting an electrode in the brain and very gently stimulating the brain every day until seizures occur. One can then measure how strong the seizure are and their duration (called after-discharge).
  • As the result of receiving CIRM Early Translation funding, we successfully generated two “xenofree” human neural stem cell lines (hNSCs) which are suitable for future therapeutic use in a variety of human neurological conditions (Goal 1). We also developed an athymic nude rat (ATN) model of controlled cortical impact TBI which exhibits sustained (2-months or longer) cognitive and emotional deficits. ATN rats lack T-cells, and thus have a sufficiently impaired immune system that they do not completely reject transplanted human cells. These ATN rats show deficits on novel place recognition (NPR), acquisition and memory of location on the Morris Water Maze, and disturbances on an Elevated Plus Maze (EPM) task in comparison to sham controls (Goal 2). We also found that sorted hNSCs survive and are not rejected in this model and that performance on the NPR task, learning on the Morris Water Maze and exploration on the EPM are all improved in the hNSC treated group compared to sham controls (Goal 3). Finally, when we repeated a therapeutic transplantation test of sorted hNSCs, but in seizure/kindled animals with TBI we found three interesting results (Goal 4). First, we replicated our earlier finding that hNSCs are efficacious in restoring memory function on the NPR task prior to kindling. Second, we found that after kindling, the improvement found with hNSCs was lost. And finally, we found that hNSCs reduce the number of After Discharge events in TBI+Kindled animals in comparison to TBI+Kindled animals that received a vehicle control injection.
  • In summary, we have successfully met all of our goals: (1) we generated a new human neural stem cell line suitable for future clinical trials in humans. (2) We developed an immunodeficient animal model of traumatic brain injury with sustained behavioral deficits. (3) We found very promising preclinical efficacy of our hNSCs in TBI. And (4), we have shown that hNSCs may play a role in reducing the number or severity of seizures following TBI, but if seizure activity is severe, that activity may interfere with hNSC mediated improvements on memory. With additional funding, we hope to complete the full range of preclinical studies required to translate these positive findings into an FDA approved human trial.
Funding Type: 
Research Leadership
Grant Number: 
LA1-08015
Investigator: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$6 368 285
Disease Focus: 
Heart Disease
Neurological Disorders
Pediatrics
Stem Cell Use: 
Embryonic Stem Cell
iPS Cell
Directly Reprogrammed Cell
Public Abstract: 

Tissues derived from stem cells can serve multiple purposes to enhance biomedical therapies. Human tissues engineered from stem cells hold tremendous potential to serve as better substrates for the discovery and development of new drugs, accurately model development or disease progression, and one day ultimately be used directly to repair, restore and replace traumatically injured and chronically degenerative organs. However, realizing the full potential of stem cells for regenerative medicine applications will require the ability to produce constructs that not only resemble the structure of real tissues, but also recapitulate appropriate physiological functions. In addition, engineered tissues should behave similarly regardless of the varying source of cells, thus requiring robust, reproducible and scalable methods of biofabrication that can be achieved using a holistic systems engineering approach. The primary objective of this research proposal is to create models of cardiac and neural human tissues from stem cells that can be used for various purposes to improve the quality of human health.

Statement of Benefit to California: 

California has become internationally renowned as home to the world's most cutting-edge stem cell biology and a global leader of clinical translation and commercialization activities for stem cell technologies and therapies. California has become the focus of worldwide attention due in large part to the significant investment made by the citizens of the state to prioritize innovative stem cell research as a critical step in advancing future biomedical therapies that can significantly improve the quality of life for countless numbers of people suffering from traumatic injuries, congenital disorders and chronic degenerative diseases. At this stage, additional investment in integration of novel tissue engineering principles with fundamental stem cell research will enable the development of novel human tissue constructs that can be used to further the translational use of stem cell-derived tissues for regenerative medicine applications. This proposal would enable the recruitment of a leading biomedical engineer with significant tissue engineering experience to collaborate with leading cardiovascular and neural investigators. The expected result will be development of new approaches to engineer transplantable tissues from pluripotent stem cell sources leading to new regenerative therapies as well as an enhanced understanding of mechanisms regulating human tissue development.

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