Neurological Disorders

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

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.

Stem Cell-Derived Astrocyte Precursor Transplants in Amyotrophic Lateral Sclerosis

Funding Type: 
Disease Team Research I
Grant Number: 
DR1-01471
ICOC Funds Committed: 
$5 694 308
Disease Focus: 
Amyotrophic Lateral Sclerosis
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
Cell Line Generation: 
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 
Amyotrophic lateral sclerosis (ALS), a lethal disease lacking effective treatments, is characterized by the loss of upper and lower motor neurons. 5-10% of ALS is familial, but the majority of ALS cases are sporadic with unknown causes. The lifetime risk is approximately 1 in 2000. This corresponds to ~30,000 affected individuals in the United States and ~5000 in the Collaborative Funding Partner country. There is currently only one FDA-approved compound, Rilutek, that extends lifespan by a maximum of three months. Although the causes of ALS are unknown and the presentation of the disease highly variable, common to all forms of ALS is the significant loss of motor neurons leading to muscle weakness, paralysis, respiratory failure and ultimately death. It is likely that many pathways are affected in the disease and focusing on a single pathway may have limited impact on survival. In addition, as ALS is diagnosed at a time that significant cell loss has occurred, an attempt to spare further cell loss would have significant impact on survival. Several findings support the approach of glial (cells surrounding the motor neurons) transplants. Despite the relative selectivity of motor neuron cell death in ALS, published studies demonstrate that glial transporters critical for the appropriate balance of glutamate surrounding the motor neurons are affected both in animal models and in tissue from sporadic and familial ALS. The significance of non-neuronal cells in the disease process has been well characterized using SOD1 mouse models representing many of the key aspects of the human disease. In addition, transplantation using glial-restricted precursors (GRPs) that differentiate into astrocytes in SOD1 mutant rats has been shown to increase survival. Motor neurons have a process, the axon, up to a meter in length which connects the cell body to its target, the muscle. The ability to appropriately rewire and ensure functional connections after motor neuron replacement remains a daunting task with no evidence to date that this will be possible in humans. Therefore, we will focus on the development of an ALS therapy based on hES-derived astrocyte precursor cell transplants to prevent the progression of ALS. Our proposed project will develop clinical grade stem-cell derived astrocyte precursor transplants for therapy in a prospective Phase I clinical trial. We will: 1) generate astrocyte precursors from three different sources of human embryonic stem cell (hESC) lines; 2) identify the hESC line and glial progenitor combination that has the best characteristics of minimal toxicity, best efficiency in generating astrocytes, and reducing disease phenotypes in vivo in a rat model of ALS; 3) manufacture the appropriate cells in a GMP facility required by the FDA; 4) work with our established clinical team to design a Phase I safety trial; and 5) submit an application for an invesitgational new drug (IND) within the next four years.
Statement of Benefit to California: 
Amyotrophic lateral sclerosis (ALS; also known as Lou Gehrig's Disease) is a common and devastating adult motor neuron disease that afflicts many Californians. In the absence of a cure, or an effective treatment, the cost of caring for patients with ALS is substantial, and the consequences on friends and family members similarly takes a devastating toll. Our goal is to develop a safe and effective cell transplant therapy for ALS by starting with human embryonic stem cells. If successful, this advance will hopefully diminish the cost of caring for the many Californians with ALS, extend their useful lives, and improve their quality of life. In addition, the development of this type of therapeutic approach in California will serve as an important proof of principle and stimulate the formation of businesses that seek to develop these types of therapies in California with consequent economic benefit.
Progress Report: 
  • Considerable progress was made on transitioning cells and cell production methods from research-scale to translational/clinical scale. Specifically, Year 1 activities were focused on transitioning from research to pilot-scale cell production methods, and characterization of the animal amyotrophic lateral sclerosis (ALS) disease model. These activities were essential because cellular therapy development is a multi-stage process with increasing stringency over time in terms of the increased focus on the details of the methods, stringent requirements for reagents/materials, greater scale, and more thorough product characterization during the transition from early research to an approved cellular therapy.
  • During Year 1, small-scale embryonic stem cell (ESC) growth and differentiation methods previously developed for research at Life Technologies were further developed at a larger pilot-scale, which provided enough cells to perform early animal pre-clinical studies and cell characterization. In addition to the increased scale of cell production, where possible, research grade reagents and materials were substituted with reagents and materials that would be required or preferred for producing a cell therapy for use in humans [produced under Good Manufacturing Practices (GMP), non-animal origin, well characterized]. These conditions are not ideal for many ESC lines, and only 1 of the 4 starting ESC lines was able to adapt successfully to these culture conditions. To increase the number of potential clinical ESC candidate cell lines, we acquired 2 additional ESC lines, UCFB6 and UCSFB7 from the University of California, San Francisco. Development is ongoing to ensure the cell processing methods are robust and scalable for the increased cell numbers required for the large-scale animal studies in Year 2. Cells from the pilot-scale production are being subjected to deep sequencing as part of the development of molecular characterization methods that may provide future quality control assays.
  • During Year 1, further studies of a rat ALS disease model were performed to: 1) optimize cell injection methods; 2) improve characterization of disease onset and progression in the rat model; 3) evaluate the utility of behavioral and electrophysiology tests for following the disease; and 4) evaluate histology methods for measuring neuron damage and detection of implanted cells, which will be used to optimize the large-scale efficacy studies planned for Year 2. We discovered that several time-consuming analysis approaches for efficacy evaluation could be replaced by simpler, more cost effective approaches. Additionally, the Year 1 studies tested and ensured that the team could handle an aggressive cell implant schedule, twice daily immunosuppression, demanding behavioral and electrophysiology assessments, and extensive histology evaluations.
  • Considerable progress was made on transitioning cells and cell production methods from research-scale to translational/clinical scale, including initial cell production in a GMP facility with GMP compatible production methods. Additionally, extensive characterization of the amyotrophic lateral sclerosis (ALS) disease animal model was completed and cells were evaluated for potential efficacy in this ALS disease animal model. These activities are key for continued progress in cellular therapy development, which is a multi-stage process that requires increasing focus on the details of the methods, stringent requirements for reagents/materials, greater scale, and more thorough product characterization during the transition to an approved cellular therapy.
  • Specifically, we made significant progress in three major areas:
  • First, we found evidence for efficacy using neural stem cells made at Life Technologies. In brief, during Year 1, the rat ALS disease model was shown to be a more aggressive disease model with an earlier disease onset and more rapid progression to end-stage and death than the model that had been used in previous studies. During Year 2, this more aggressive ALS disease model was further characterized with the identification of a reliable marker of disease onset, and demonstration that alpha motor neuron sparing by implanted cells could be detected and measured even, despite the aggressive nature of disease progression in this rat model.
  • We found that H9 NSCs produced by Life Technologies, when implanted into the rat ALS disease model, survived, migrated extensively into the area where alpha motor neurons are located, differentiated into cells that appear to be astrocytes, and provided a protective effect for the alpha motor neurons. This protective effect was determined by comparing the survival of alpha motor neurons on the side of the rat spinal cord where NSCs were implanted with the side of the spinal cord that did not have cells implanted. The side of the spinal cord where the NSCs were implanted showed approximately 10% more surviving alpha motor neurons than the matching side of the spinal cord that did not have cells implanted.
  • Second, cells from the various production methods were subjected to gene sequencing as part of the development of molecular characterization methods. This sequencing information was critical to identify whether cells produced by various methods were typical for the cell type, or exhibited qualities that indicated they were not optimal cell populations. These methods will be used to identify optimal markers for characterizing cell populations as part of current cell production development and for future quality control assays.
  • Third, during Year 2, Life Technologies further developed their pilot-scale embryonic stem cell (ESC) growth and differentiation methods to be more easily adaptable to cell production under Good Manufacturing Practices (GMP). This involved increasing the scale of cell production, and where possible, substituting reagent grade reagents and materials with reagents and materials that would be required or preferred for producing a cell therapy for use in humans (produced GMP, non-animal origin, well characterized). These conditions are not ideal for many ESC lines, and in Year 1, only one (H9) of the 4 starting ESC lines was successfully adapted to these culture conditions, however, 3 additional ESC lines were acquired to increase the number of potential clinical ESC candidate cell lines. One of these ESC lines (UCSFB7 from the University of California, San Francisco) was successfully adapted to the pilot ESC culture conditions, and resulted in the production of NSCs, and with AP production in progress. Because the research version of ESC line H9 has been used to successfully produce NSCs at Life Technologies, agreements are in progress for City of Hope for NSC cell production using the H9 ESCs, that have been banked under GMP conditions at City of Hope. In addition, pilot-scale cell production was initiated earlier than originally planned at the University of California, Davis GMP facility. The plan is to produce NSCs and APs under conditions that UC Davis has found to be successful in the past, and transition these methods to GMP compliance. To date, UC Davis has produced ESCs from 3 ESC lines [UCSF4, UCSF4.2 (a.k.a. UCSFB6) and UCSF4.3 (a.k.a. UCSFB7] and has produced NSCs from ESC line UCSF4. The UCSF4 NSCs are scheduled to be shipped to UCSD for testing in the ALS disease animal model in early June, 2012, and NSC production from ESC lines UCSF4.2 and UCSF4.3 is expected to begin in late June 2012.

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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