Neurological Disorders

Coding Dimension ID: 
303
Coding Dimension path name: 
Neurological Disorders
Funding Type: 
New Cell Lines
Grant Number: 
RL1-00678
Investigator: 
Type: 
PI
ICOC Funds Committed: 
$1 369 800
Disease Focus: 
Huntington's Disease
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
iPS Cell
Cell Line Generation: 
Embryonic Stem Cell
iPS Cell
oldStatus: 
Closed
Public Abstract: 

Huntington’s disease (HD) is a devastating neurodegenerative disease with a 1/10,000 disease risk that always leads to death. These numbers do not fully reflect the large societal and familial cost of HD, which requires extensive caregiving and has a 50% chance of passing the mutation to the next generation. Current treatments treat some symptoms but do not change the course of disease. Symptoms of the disease include movement abnormalities, inability to perform daily tasks and and psychiatric problems. A loss os specific regions of the brain are observed. The mutation for HD is an expansion of a region of repeated DNA in the HD gene and the longer the repeat, in general the earlier the onset of disease. While the length of this polyglutamine repeat largely determines the age-of-onset, there is variance in onset age that is not accounted for by repeat length but is determined by genetic and environmental factors. In addition, the symptoms can vary significantly among patients in a non-repeat dependent manner. To assist in preventing onset of HD, there is a great need to identify genes that are involved in why one individual with 45 repeats will manifest symptoms at age 40 while another manifests symptoms at age 70. Further, there is a lack of early readouts to determine when to begin HD treatments. Because the disease mutation is known, preimplantation genetic diagnosis (PGD) is possible and mutant Htt embryos are available. Stem cell lines can be derived from PGD embryos with varying repeat lengths and genetic backgrounds to provide new methods to identify genetic modifiers and readouts of disease progression. The development of pluripotent stem cells, termed induced pluripotent stem cells (iPS) cells, derived directly from HD patient fibroblasts, would also provide new methods for these analyses. Chemical compound screens to identify drugs that protect against the effect of mutant Htt protein expression in patient derived hESCs cells would allow evaluation of drug responses in on cells having different genetic backgrounds Ultimately, the iPS cells can provide a way to transplant neurons or neuronal support cells from affected individuals or from unaffected family members having a normal range repeat. Such cells would help reduce immune rejection effects likely to occur with transplantation, however, while patient-derived cells overcome the problems of immune rejection, the mutant protein is still expressed. To overcome this problem we will genetically modify these stem cells to reduce the mutant protein and produce a normal gene. Beyond the immediate application to HD, the development of these models is applicable to a range of neurodegenerative diseases including Alzheimer’s and Parkinson’s diseases.

Statement of Benefit to California: 

The disability and loss of earning power and personal freedom resulting from Huntington's disease (HD) is devastating and creates a financial burden for California. Individuals are struck in the prime of life, at a point when they are their most productive and have their highest earning potential. Further, as the disease progressives, individuals require institutional care facilities at great financial cost. Therapies using human embryonic stem cells (hESCs) have the potential to change the lives of hundreds of individuals and their families, which brings the human cost into the thousands. Further, hESCs from HD patients will help us understand the factors that dictate the course of the disease and provide a resource for drug development. For the potential of hESCs in HD to be realized, a very forward approach such as that proposed will allow experienced investigators in HD and stem cell research and clinical trials to come together and create cell lines to more fully mimic the diseases neurons and allow for future treatment options. The federal constraints on hESCs create a critical need for the development of treatments using hESCs supported and staffed with non-federal funds. We have proposed goals and strategies for generating new stem cells derived from patient preimplantation diagnosis embryos and patient fibroblasts. We have put in place critical milestones to be met We will build on existing regional stem cell resources . Anticipated benefits to the citizens of California include: 1) development of new stem cell lines that will allow us to more closely model the disease for mechanistic studies and drug screening, 2) improved methods for following the course of the disease in order to treat HD as early as possible before symptoms are manifest; 3) development of new cell-based treatments for Huntington's disease with application to other neurodegenerative diseases such as Alzheimer's and Parkinson's diseases that affect thousands of individuals in California; 4) development of intellectual property that could form the basis of new biotech startup companies; and 5) improved methods for drug development that could directly benefit citizens of the state.

Progress Report: 
  • Huntington’s disease (HD) is a devastating neurodegenerative disease with a 1/10,000 disease risk that always leads to death. These numbers do not fully reflect the large societal and familial cost of HD, which requires extensive caregiving and has a 50% chance of passing the mutation to the next generation. Current treatments treat some symptoms but do not change the course of disease. Symptoms of the disease include movement abnormalities, inability to perform daily tasks and psychiatric problems. A loss of specific regions of the brain are observed. The mutation for HD is an expansion of a region of repeated DNA in the HD gene and the longer the repeat, in general the earlier the onset of disease. While the length of this polyglutamine repeat largely determines the age-of-onset, there is variance in onset age that is not accounted for by repeat length but is determined by genetic and environmental factors. In addition, the symptoms can vary significantly among patients in a non-repeat dependent manner. There is a lack of early readouts to determine when to begin HD treatments. Because the disease mutation is known, preimplantation genetic diagnosis (PGD) is possible and mutant Htt embryos are available. We have obtained a number of HD PGD embryos with varying repeat lengths and genetic backgrounds to derive hES cell lines and provide new methods to identify genetic modifiers and readouts of disease progression. Development of multiple lines has begun during this funding period. The development of pluripotent stem cells, termed induced pluripotent stem (iPS) cells, derived directly from HD patient fibroblasts, also provide new methods for these analyses. We have begun the establishment of a bank of HD fibroblasts and have derived three new iPS lines to date with unique CAG repeat expansions. Characterization of the lines for HD phenotypes is in progress. An additional line is being generated and additional fibroblast collection from both HD patients and individuals who do not carry the HD gene is planned for the coming year to generate other sets of iPS lines. These lines will allow mechanistic studies and chemical compound screens to identify drugs that protect against the effect of mutant Htt protein expression in patient derived stem cells to be performed. Ultimately, the iPS cells will provide a way to transplant neurons or neuronal support cells from affected individuals or from unaffected family members having a normal range repeat. Such cells would help reduce immune rejection effects likely to occur with transplantation, however, while patient-derived cells overcome the problems of immune rejection, the mutant protein is still expressed. To overcome this problem we will genetically modify these stem cells to reduce the mutant protein and produce a normal gene in the next portion of the project.
  • Huntington’s disease (HD) is a devastating neurodegenerative disease that strikes in mid-life and inevitably leads to death. As it is genetic, offspring of affected individuals are 50% at risk. Current medications treat some symptoms, which include movement abnormalities, inability to perform daily tasks and psychiatric problems, but do not change the course of disease. The mutation for HD is an expansion of a region of repeated DNA in the HD gene. In general, the longer the repeat the earlier the onset of disease. While the length of this polyglutamine repeat largely determines the age-of-onset, there is variance in onset age that is not accounted for by repeat length but is determined by genetic and environmental factors. In addition, the symptoms can vary significantly among patients in a non-repeat dependent manner. There is a lack of early readouts to determine when to begin HD treatments. Because the disease mutation is known, preimplantation genetic diagnosis (PGD) is possible and mutant Htt embryos are available. We have obtained a number of HD PGD embryos with varying repeat lengths and genetic backgrounds to derive hES cell lines and have derived a line that is now fully characterized as a stem cell line. The development of pluripotent stem cells, termed induced pluripotent stem (iPS) cells, derived directly from HD patient skin cells (fibroblasts), also provide new methods for these analyses. We have made significant progress in establishing a bank of HD fibroblasts and have derived seven new iPS lines to date with unique CAG repeat expansions. Characterization of the lines for HD phenotypes is either complete or in progress. Additional lines are being generated and additional fibroblast collection from both HD patients and individuals who do not carry the HD gene is planned for the coming year to generate other sets of iPS lines. These lines will allow mechanistic studies and chemical compound screens to identify drugs that protect against the effect of mutant Htt protein expression in patient derived stem cells to be performed.
  • Huntington’s disease (HD) is a devastating neurodegenerative disease that strikes in mid-life and inevitably leads to death. As it is genetic, offspring of affected individuals are 50% at risk. Current medications treat some symptoms, which include movement abnormalities, inability to perform daily tasks and psychiatric problems, but do not change the course of disease. The mutation for HD is an expansion of a region of repeated DNA in the HD gene. In general, the longer the repeat the earlier the onset of disease. While the length of this polyglutamine repeat largely determines the age-of-onset, there is variance in onset age that is not accounted for by repeat length but is determined by genetic and environmental factors. In addition, the symptoms can vary significantly among patients in a non-repeat dependent manner. There is a lack of early readouts to determine when to begin HD treatments. Because the disease mutation is known, preimplantation genetic diagnosis (PGD) is possible and mutant Htt embryos are available. We have obtained HD PGD embryos and have derived a line that is now fully characterized as a stem cell line that is capable of becoming brain cells. The development of pluripotent stem cells, termed induced pluripotent stem (iPS) cells, derived directly from HD patient skin cells (fibroblasts), also provide new methods for these analyses. We have established a bank of HD fibroblasts and have derived seven new iPS lines with unique CAG repeat expansions. Characterization of the lines for HD symptoms is either complete or in progress. Additional lines are being generated and additional skin cells collected from both HD patients and individuals who do not carry the HD gene. These lines are allowing mechanistic studies and chemical compound screens to identify drugs that protect against the effect of mutant Htt protein expression in patient derived stem cells to be performed. Finally, we are developing a method to reduce the level of the mutant protein to provide options for future transplantation from an individual's own skin cells to prevent immune rejection.
Funding Type: 
New Cell Lines
Grant Number: 
RL1-00650
Investigator: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$1 708 560
Disease Focus: 
Dementia
Neurological Disorders
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Closed
Public Abstract: 

We propose to generate induced pluripotent stem (iPS) cells from skin cells derived from human subjects with frontotemporal dementia (FTD). FTD accounts for 15–20% of all dementia cases and, with newly identified genetic causes, is now recognized as the most common dementia in patients under 65 years of age. FTD patients suffer progressive neurodegeneration in the frontal and temporal lobes and other brain regions, resulting in behavioral changes and memory and motor neuron deficits. The median age of onset for this devastating disease is 58 years, and disease progression is rapid, with death in 3–8 years. Compared with other age-dependent neurodegenerative diseases, the molecular, cellular, and genetic bases of FTD remain poorly understood. Genetic causes are estimated to account for ~40% of FTD. In addition to tau identified in 1998, mutations in three causative genes have been identified during the last three years. The identification of FTD mutations opens exciting new avenues for understanding the causes of FTD. Research on these mutations will help to identify effective therapies. However, the ability to study the functions of these factors is severely limited due to the lack of available human neurons from FTD patients. To address the need for disease– and patient–specific neurons, we will use the powerful new technique of iPS cells. iPS cells are derived from skin cells and can be used to generate any cell types in the body, including neurons. We will obtain human skin cells from FTD patients with disease-causing mutations and generate many FTD mutation–specific iPS cell lines. We will then use these iPS cells to generate FTD mutation–specific neurons to study disease mechanisms. The bank of iPS cell lines we generate will also enable the development of sensitive assays for drug screening and testing of therapeutic agents for treating FTD. All cell lines will be made available to the global FTD research community. The generation of human neurons from FTD patients will be a tremendous advance toward finding a cure for this disease.

Statement of Benefit to California: 

California is the U.S. leader in basic research into stem cell–based therapies for disease. To help California remain at the forefront of research on neurological disease, we propose to use induced pluripotent stem (iPS) cells—a revolutionary new technique developed recently by Dr. Shinya Yamanaka—to target frontotemporal dementia (FTD). FTD is a devastating and common form of dementia. {REDACTED} The proposed research will establish California as the leader in generating human patient–specific neurons from iPS cells. The potential long-term benefits to California include growth of the clinical enterprise in the diagnosis and treatment of FTD, the establishment of biotechnology to generate new drugs for FTD, and potential intellectual properties for driving private enterprises to develop therapies.

Progress Report: 
  • In this grant, we proposed to generate induced pluripotent stem (iPS) cells from skin cells derived from human subjects with frontotemporal dementia (FTD). FTD accounts for 15–20% of all dementia cases and, with newly identified genetic causes, is now recognized as the most common dementia in patients under 65 years of age. FTD patients suffer progressive neurodegeneration in the frontal and temporal lobes and other brain regions, resulting in behavioral changes and memory and motor neuron deficits. The median age of onset of this devastating disease is 58 years, and it progresses rapidly, causing death in 3–8 years. Compared with other age-dependent neurodegenerative diseases, the molecular, cellular, and genetic bases of FTD are poorly understood. Genetic causes are estimated to account for ~40% of FTD. In addition to tau identified in 1998, mutations in three causative genes have been identified during the last three years. The identification of FTD mutations opens exciting new avenues for understanding the causes of FTD. Research on these mutations will help to identify effective therapies. However, the ability to study the functions of these factors is severely limited due to the lack of available human neurons from FTD patients. To address the need for disease– and patient–specific neurons, we proposed to use the powerful new technique of iPS cells. iPS cells are derived from skin cells and can be used to generate any cell types in the body, including neurons. During the last 10 months, we have obtained human skin cells from more than 30 FTD patients with disease-causing mutations and unaffected family members. We have generated about 200 putative iPS cell lines from two FTD patients with defined genetic mutations, one sporadic case, and one control. We characterized some of the iPS cell lines and differentiated one patient-specific iPS cell line into human postmitotic neurons. These results represent a major advance toward finding a cure for FTD, and we will continue to pursue this line of research as proposed.
  • We have collected numerous skin samples from patients with a kind of dementia that affects the frontal lobes. We have also collected samples from unaffected family members (controls). For many of these samples we have made induced pluripotent stem cells (iPS), which can give rise to any cell type. We are in the process of generating neurons from these stem cells. Our hope and intention is to study these cells to learn about the mechanisms that give rise to this dementia and to be able to test potential therapies.
  • We have collected numerous skin samples from patients with a kind of dementia that affects the frontal lobes. We have also collected samples from unaffected family members (controls). For many of these samples we have made induced pluripotent stem cells (iPS), which can give rise to any cell type. We are in the process of generating neurons and other cell types, such as cells that mediate inflammation, from these stem cells. Our hope and intention is to study these cells to learn about the mechanisms that give rise to this dementia and to be able to test potential therapies.
Funding Type: 
New Cell Lines
Grant Number: 
RL1-00649
Investigator: 
Name: 
Type: 
PI
ICOC Funds Committed: 
$1 737 720
Disease Focus: 
Amyotrophic Lateral Sclerosis
Neurological Disorders
Autism
Blood Disorders
Rett's Syndrome
Neurological Disorders
Pediatrics
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Closed
Public Abstract: 

Human embryonic stem cells (hESC) hold great promise in regenerative medicine and cell replacement therapies because of their unique ability to self-renew and their developmental potential to form all cell lineages in the body. Traditional techniques for generating hESC rely on surplus IVF embryos and are incompatible with the generation of genetically diverse, patient or disease specific stem cells. Recently, it was reported that adult human skin cells could be induced to revert back to earlier stages of development and exhibit properties of authentic hES cells. The exact method for “reprogramming” has not been optimized but currently involves putting multiple genes into skin cells and then exposing the cells to specific chemical environments tailored to hES cell growth. While these cells appear to have similar developmental potential as hES cells, they are not derived from human embryos. To distinguish these reprogrammed cells from the embryonic sourced hES cells, they are termed induced pluripotent stem (iPS) cells. Validating and optimizing the reprogramming method would prove very useful for the generation of individual cell lines from many different patients to study the nature and complexity of disease. In addition, the problems of immune rejection for future therapeutic applications of this work will be greatly relieved by being able to generate reprogrammed cells from individual patients. We have initiated a series of studies to reprogram human and mouse fibroblasts to iPS cells using the genes that have already been suggested. While induction of these genes in various combinations have been reported to reprogram human cells, we plan to optimize conditions for generating iPS cells using methods that can control the level of the “reprogramming” genes, and also can be used to excise the inducing genes once reprogramming is complete; thus avoiding unanticipated effects on the iPS cells. Once we have optimized the methods of inducing human iPS cells from human fibroblasts, we will make iPS cells from patients with 2 different neurological diseases. We will then coax these iPS cells into specific types of neurons using methods pioneered and established in our lab to explore the biological processes that lead to these neurological diseases. Once we generate these cell based models of neural diseases, we can use these cells to screen for drugs that block the progress, or reverse the detrimental effects of neural degeneration. Additionally, we will use the reprogramming technique to study models of human blood and liver disease. In these cases, genetically healthy skin cells will be reprogrammed to iPS cells, followed by introduction of the deficient gene and then coaxed to differentiate into therapeutic cell types to be used in transplantation studies in animal models of these diseases. The ability of the reprogrammed cell types to rescue the disease state will serve as a proof of principle for therapeutic grafting in

Statement of Benefit to California: 

It has been close to a decade since the culture of human embryonic stem (hES) cells was first established. To this day there are still a fairly limited number of stem cell lines that are available for study due in part to historic federal funding restrictions and the challenges associated with deriving hES cell lines from human female egg cells or discarded embryos. In this proposal we aim to advance the revolutionary new reprogramming technique for generating new stem cell lines from adult cells, thus avoiding the technical and ethical challenges associated with the use of human eggs or embryos, and creating the tools and environment to generate the much needed next generation of human stem cell lines. Stem cells offer a great potential to treat a vast array of diseases that affect the citizens of our state. The establishment of these reprogramming techniques will enable the development of cellular models of human disease via the creation of new cell lines with genetic predisposition for specific diseases. Our proposal aims to establish cellular models of two specific neurological diseases, as well as developing methods for studying blood and liver disorders that can be alleviated by stem cell therapies. California has thrived as a state with a diverse population, but the stem cell lines currently available represent a very limited genetic diversity. In order to understand the variation in response to therapeutics, we need to generate cell lines that match the rich genetic diversity of our state. The generation of disease-specific and genetically diverse stem cell lines will represent great potential not only for CA health care patients but also for our state’s pharmaceutical and biotechnology industries in terms of improved models for drug discovery and toxicological testing. California is a strong leader in clinical research developments. To maintain this position we need to be able to create stem cell lines that are specific to individual patients to overcome the challenges of immune rejection and create safe and effective transplantation therapies. Our proposal advances the very technology needed to address these issues. As a further benefit to California stem cell researchers, we will be making available the new stem cell lines created by our work.

Progress Report: 
  • Public Summary for: CIRM New Cell Line Project - Progress Report.
  • Our research team has been working over the last year on developing new human stem cell lines that are specifically useful for studying human diseases and developing new therapeutic strategies. Human embryonic stem (hES) cells were first established in 1998 and in the past decade have been shown to be capable to differentiating to a vast array of different cell types. This full developmental potential is termed pluripotency. Until recently these were the only established human cell type that could be robustly grown in the laboratory setting and still maintain full pluripotent developmental potential. In November of 1997, a new type of human pluripotent cell was created. By turning on a set of 4 genes, researchers succeeded in reprogramming human skin cells back into a cell type that appeared to have very similar properties and potential as the hES cell. These new stem cells are called induced pluripotent stem (iPS) cells in order to keep the name distinct from their embryonic derived counterpart. One of the scientific limitations of hES cells is the impracticality of generating patient or disease specific stem cell lines. This opportunity now becomes theoretically practical with the advent of human iPS cell line generation. We report here on significant progress demonstrating the practicality of generating disease-linked cellular models of human diseases.
  • We have identified 2 specific human neurological diseases that have a known, or strongly suggested genetic component, and have set about to generate disease-linked iPS cell lines. We have obtained skin cell samples from patients with these neurological diseases and have successfully reprogrammed them back to iPS cells. These disease-linked pluripotent stem cells have been carefully characterized and we have demonstrated that they do indeed behave very similar to existing hES cells and also to the genetically healthy control iPS cell lines that we have generated. Therefore the disease phenotype is not detrimental to reprogramming or proliferation as a stem cell. Furthermore, we have succeeded in coaxing these disease-linked iPS cells to turn into specific types of human neurons, the very cells that are suspected to be involved in the neurological disorders. We now have established a viable model for studying human neural disorders in the laboratory, and have already observed some potentially important functional differences between the disease-linked and control iPS generated neurons. In the coming year we will be evaluating the differences between the disease-linked and control neurons and investigating potential therapeutic approaches to stop or reverse the defects.
  • We have also been working on developing new methods for generating iPS cells that will make them more useful in clinical or pre-clinical settings where it is important that the original set of 4 genes used to reprogram the skin cells are removed once they have become iPS cells. Significant progress has been made in this regard and will be completed in the coming year. Looking forward we will also be applying this approach to generate human disease-linked iPS cells for specific hematological (blood) related disorders. The derivation of iPS-based models of hematological disorders will allow us develop gene therapy approaches to correct the disease causing defects and establish proof of principle for therapeutic approaches.
  • This research project is focused on developing new human stem cell lines that are specifically useful for studying human diseases and developing new therapeutic strategies. Human embryonic stem (hES) cells were first established in 1998 and in the past decade have been shown to be capable of differentiating to a vast array of different cell types. This full developmental potential is termed "pluripotency." Until recently these were the only established human cell types that could be robustly grown in the laboratory setting and still maintain full pluripotent developmental potential. In November 1997 a new type of human pluripotent cell was created. By turning on a set of 4 genes, researchers succeeded in reprogramming human skin cells back into a cell type that appeared to have very similar properties and potential as the hES cell. These new stem cells are called induced pluripotent stem (iPS) cells in order to keep the name distinct from their embryonic derived counterpart. One of the scientific limitations of hES cells is the impracticality of generating patient or disease specific stem cell lines. This opportunity now becomes theoretically practical with the advent of human iPS cell line generation. We report here on significant progress demonstrating the practicality of generating disease-linked cellular models of human diseases.
  • We have identified 2 specific human neurological diseases that have known, or strongly suggested, genetic components and have set about to generate disease-linked iPS cell lines. We have obtained skin cell samples from patients with these neurological diseases and have successfully reprogrammed them back to iPS cells. These disease-linked pluripotent stem cells have been carefully characterized and we have demonstrated that they do indeed behave very similar to existing hES cells and also to the genetically healthy control iPS cell lines that we have generated. Therefore, the disease phenotype is not detrimental to reprogramming or proliferation as a stem cell. Furthermore, we have succeeded in coaxing these disease-linked iPS cells to turn into specific types of human neurons, the very cells that are suspected to be involved in the neurological disorders. We now have established a viable model for studying human neural disorders in the laboratory, and have already observed some potentially important functional differences between the disease-linked and control iPS-generated neurons. Importantly, we have found defects in the function of disease-linked neurons that can be corrected in part following specific drug treatments. This discovery demonstrates the potential utility to use this method of modeling human diseases in the laboratory as a tool for understanding the detailed pathways, which might contribute to the development of the disease state and, importantly, as a target for screening potential therapeutic compounds that might be used to block or slow the progress of human neural disorders. In the coming year we will finalize our efforts on this project.
  • We have also succeeded in developing an improved method for the delivery of the reprogramming genes into the patient cells in order to become iPS cells. This method allows the reprogramming genes to be removed thus mitigating the potential for unwanted and potentially detrimental reactivation of these reprogramming genes subsequent to the iPS cell state. We have begun work using this new reprogramming methodology to generate iPS cell lines that are specifically linked to diseases of the blood and immune system. The new methodology appears to be working well and we anticipate completing the generation and characterization of these new disease-linked stem cell lines within the next year of this project.
  • This research project has been focused on developing new human stem cell lines that are specifically useful for studying human diseases and developing new therapeutic strategies. Human embryonic stem (hES) cells were first established in 1998 and in the past decade have been shown to be capable to differentiating of a vast array of different cell types. This full developmental potential is termed "pluripotency". Until recently these were the only established human cell type that could be robustly grown in the laboratory setting and still maintain full pluripotent developmental potential. In November of 2007, a new type of human pluripotent cell was created. By turning on a set of 4 genes, researchers succeeded in reprogramming human skin cells back into a cell type that appears to have very similar properties and potential as the hES cell. These new stem cells are called induced pluripotent stem (iPS) cells in order to keep the name distinct from their embryonic derived counterpart. One of the scientific limitations of hES cells is the impracticality of generating patient or disease specific stem cell lines. This opportunity now becomes theoretically practical with the advent of human iPS cell line generation. We report here on significant progress demonstrating the practicality of generating disease-linked cellular models of human diseases.
  • We have identified 2 specific human neurological diseases, Rett’s Syndrome and Schizophrenia that have a known, or strongly suggested genetic components, and have set about to generate disease-linked iPS cell lines. We have obtained skin cell samples from patients with these neurological diseases and have successfully reprogrammed them back to iPS cells. These disease-linked pluripotent stem cells have been carefully characterized and we have demonstrated that they do indeed behave very similar to existing hES cells and also to the healthy control iPS cell lines that we have generated. Therefore, the disease phenotype is not detrimental to reprogramming or proliferation as a stem cell. Furthermore, we have succeeded in coaxing these disease-linked iPS cells to turn into specific types of functional human neurons, the very cells that are suspected to be involved in the neurological disorders. We now have established a viable model for studying human neural disorders in the laboratory, and have already observed some potentially important functional differences between the disease-linked and control iPS generated neurons. Importantly, we have found defects in the function of disease-linked neurons that can be corrected in part following specific drug treatments. This discovery demonstrates the potential utility to use this method of modeling human diseases in the laboratory as a tool for understanding the detailed pathways that might contribute to the development of the disease state and importantly as a target for screening potential therapeutic compounds that might be used to block or slow the progress of human neural disorders.
  • We have also succeeded in developing an improved method for the delivery of the reprogramming genes into the patient cells in order to become iPS cells. This method combines all the of the reprogramming genes into a single cassette, and also allows the reprogramming genes to be removed thus mitigating the potential for unwanted and potentially detrimental reactivation of these reprogramming genes subsequent to the iPS cell state. We have demonstrated the success of this new reprogramming methodology to generate iPS cell lines that are specifically linked to a disease of the immune system. In addition to creating a panel of disease-linked iPS cell lines that are free of the externally introduced reprogramming transgenes, we have shown progress in achieving correction of the DNA mutation that leads to the disease state. Our extended research on these new disease specific iPS cell lines has shown utility for creating in vitro models of human neural disorders, and potential for genetically corrected patient specific iPS cell lines that could be used for cell based transplantation therapies.
Funding Type: 
Comprehensive Grant
Grant Number: 
RC1-00346
Investigator: 
ICOC Funds Committed: 
$2 507 223
Disease Focus: 
Parkinson's Disease
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 

Parkinson’s disease (PD) is caused by degeneration of a specific population of dopamine-producing nerve cells in the brain and is chronic, progressive, and incurable. Loss of dopamine-containing cells results in profound physiological disturbances producing tremors, rigidity, and severe deterioration of gate and balance. In the United States, approximately 1.5 million people suffer with PD and it is estimated that 60,000 new cases are diagnosed each year. Drugs can modify some of the disease symptoms, but many patients develop disabling drug-induced movements that are unresponsive to medication. Deep brain stimulation can alleviate motor symptoms in some patients but is not a cure. We plan an entirely novel approach to treat PD. We propose to utilize a specific class of inhibitory nerve cells found in the embryonic brain, known as MGE cells, as donor transplant cells to inhibit those brain regions whose activity is abnormally increased in PD. In preliminary studies we have demonstrated that this approach can relieve symptoms in an animal model of PD. To turn this approach into a patient therapy, we will need to develop methods to obtain large numbers of human cells suitable for transplantation. This proposal seeks to address this problem by producing unlimited numbers of exactly the right type of MGE nerve cell using human embryonic stem cells.

The inhibitory nerve cells we seek to produce will reduce brain activity in target regions. They may therefore be used to treat other conditions characterized by excessive brain activity, such as epilepsy. Epilepsy can be a life threatening and disabling condition. Nearly two million Americans suffer with some form of epilepsy. Unfortunately, modulation of brain excitability using antiepileptic drugs can have serious side-effects, especially in the developing brain, and many patients can only be improved by surgically removing areas of the brain containing the seizure focus. Using MGE cells made from human embryonic stem cell lines, we hope to develop a novel epilepsy treatment that could replace the need for surgery or possibly even drug therapy.

We propose an integrated approach that combines the complementary expertise of four UCSF laboratories to achieve our goals. We have already determined that mouse MGE cells can improve the symptoms of PD and epilepsy when grafted into animal models. We now need to develop methods to obtain large numbers of human cells suitable for grafting. We need to ensure that when delivered, the cells will migrate and integrate in the target brain regions, and we need to evaluate therapeutic efficacy in animal models of Parkinson’s disease and epilepsy. This proposal addresses these goals. If successful, this accomplishment will set the stage for studies in primates and hasten the day when MGE cells may be used as patient therapy for a wide variety of debilitating neurological disorders.

Statement of Benefit to California: 

This collaborative proposal promises to accelerate progress toward a novel cell based therapeutic agent with potentially widespread benefit for the treatment of a variety of grave neurological disorders. The promise of this work to eventually help our patients is our primary motivation. Additionally, our studies, if successful, could form the basis of a new stem cell technology to produce unlimited numbers of cellular therapeutic products of uniform quality and effectiveness. The production of neurons from stable nerve cell lines derived from human embryonic stem cells is a much-needed biotechnology and a central challenge in embryonic stem (ES) cell biology. Current methods are inefficient at producing neurons that can effectively migrate and integrate into adult brain, and available cell lines generally lack the ability to differentiate into specific neuronal subtypes. Moreover, while many cells resist neuronal differentiation others often take on a glial cell fate. Identification of key factors driving ES cells into a specific neuronal lineage is the primary focus of the current proposal, and if achieved, will generate valuable intellectual property. As such, it may attract biotechnology interest and promote local business growth and development. Moreover, the inhibitory nerve cell type that is the goal of this proposal would be a potentially valuable therapeutic agent. This achievement could attract additional funding from state or industry to begin primate studies and ultimately convert any success into a safe and effective product for the treatment of patients. To produce and distribute stable medicinal-grade cells of a purity and consistency appropriate for therapeutic use will require partnering with industry. Industry participation would be expected to provide economic benefits in terms of job creation and tax revenues. Hopefully, there may ultimately be health benefits for the citizens of California who are suffering from neurological disease.

Progress Report: 
  • Our goal is to develop a novel cell-based therapy to treat patients with epilepsy, Parkinson’s disease and brain injury. The strategy is to use human embryonic stem cells to produce inhibitory nerve cells for transplantation and therapeutic modulation of neural circuits, an approach that may have widespread clinical application. In preliminary studies using inhibitory neuron precursors from embryonic rodent brains, we have demonstrated that this approach can relieve symptoms in animal models of Parkinson’s disease and epilepsy. To turn this approach into a patient therapy we need to develop methods to obtain large numbers of human cells suitable for transplantation. The object of this proposal is to develop methods for producing unlimited numbers of exactly the right type of inhibitory nerve cell using human embryonic stem (ES) cells as the starting material.
  • One strategy to make large numbers of inhibitory neurons would be to convert human ES cells into neural stem (NS) cell lines that could be stably propagated indefinitely, and then to convert the NS cells into inhibitory nerve cells. However, we discovered that NS cell lines do not retain the capacity to generate neurons after extended culture periods but instead produce only glial cells. We have therefore begun to create neurons directly from ES cells, without interrupting the differentiation to amplify cell number at the neural progenitor phase. Using this approach, we have been successful at specifying the right pathway to produce the specific neural progenitor cell we need during the process of differentiation from ES cells. Because there are multiple subytpes of inhibitory neuron, we are testing various cell culture manipulations to enrich for the specific neuron subtype that matches our desired cell type. In addition, we are developing reporter cell lines that will allow us to observe differentiation from ES cell to inhibitory neuron in real time and purify the cells of interest for transplantation. Finally, we are also testing whether artificially expressing key proteins that regulate gene expression and are required for inhibitory neuron production during brain development can more efficiently drive a high percentage of ES cells to differentiate into the desired cell type.
  • With these tools in place, we hope to begin animal transplantation studies using human ES-derived inhibitory nerve cells within the coming year. If successful, this accomplishment will set the stage for studies in primates, and hasten the day when inhibitory nerve cells may be used as patient therapy for a wide variety of debilitating neurological disorders including Parkinson’s disease, epilepsy, and brain injury.
  • This past year, we have made significant strides toward the production of inhibitory nerve cells and precursor (MGE) cells from human embryonic stem (ES) and induced pluripotent stem (iPS) cells. These stem cell-derived MGE progenitor cells appropriately mature into inhibitory neurons upon further culture and following transplantation into the newborn mouse brain. Additionally, human ES cell-derived inhibitory neurons possess active membrane properties by electrophysiology analysis. Work is ongoing to determine their functional potential following transplantation: whether these cells can make connections, or synapses, with each other and with neurons in the host brain in order to elevate inhibitory tone in the transplanted animals. Following successful completion of this aim in the coming year, we will be well positioned to examine the therapeutic potential of these cells in pre-clinical epilepsy and Parkinson's disease animal models.
  • Inhibitory nerve cell deficiencies have been implicated in many neurological disorders including epilepsy. The decreased inhibition and/or increased excitation lead to hyper-excitability and brain imbalance. We are pursuing a strategy to re-balance the brain by injecting inhibitory nerve precursor cells. Most inhibitory nerve cells come from the medial ganglionic eminence (MGE) during fetal development. We have previously documented that mouse MGE transplants reduce seizures in animal models of epilepsy and ameliorate motor symptoms in a rat model of Parkinson’s disease. This project aims to develop human MGE cells from human embryonic stem (ES) cells and to investigate their function in animal models of human disease. In the past year, we have successfully developed a robust and reproducible method to generate human ES cell-derived MGE cells and have performed extensive gene expression and functional analyses. The gene expression profiles of these ES-derived MGE cells resemble those of mouse and human fetal MGE. They appropriately mature into inhibitory nerve cells in culture and following injection into rodent brain. Also, the ES-derived inhibitory cells exhibit active electrical properties and establish connections (synapses) with other nerve cells in culture and in the rodent brain. Thus, we have succeeded in deriving inhibitory human MGE cells from human ES cells and are now transplanting these cells into animal models of disease.
Funding Type: 
Comprehensive Grant
Grant Number: 
RC1-00345
Investigator: 
Type: 
PI
ICOC Funds Committed: 
$2 396 932
Disease Focus: 
Amyotrophic Lateral Sclerosis
Neurological Disorders
Spinal Muscular Atrophy
Spinal Cord Injury
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 

Cervical spinal cord injuries result in a loss of upper limb function because the cells within the spinal cord that control upper limb muscles are destroyed. The goal of this research program is to create a renewable human source of these cells, to restore upper limb function in both acute and chronic spinal cord injuries. There are two primary challenges to the realization of this goal: 1) a source of these human cells in high purity, and 2) functional integration of these cells in the body after transplantation.

Human embryonic stem cells (hESCs) can form any cell in the body, and can reproduce themselves almost indefinitely to generate large quantities of human tissue. One of the greatest challenges of hESC research is to find ways to restrict hESCs such that they generate large amounts on only one cell type in high purity such that they could be used to replace lost cells in disease or trauma. Our laboratory was the first laboratory in the world to develop a method to restrict hESCs such that they generate large amounts of only one cell type in high purity. That cell type is called an oligodendrocyte, which insulates connections in the spinal cord to allow them to conduct electricity. Transplantation of these cells was useful for treating spinal cord injuries in rats if the treatment was given one week after the injury. That treatment is being developed for use in humans.

Recent studies in our laboratory indicate that we have succeeded in restricting hESCs to generate large quantities of a different cell type in the spinal cord, that which controls upper limb muscles. We have generated large quantities of these human cells, grown them with human muscle, and demonstrated that they connect and control the human muscle. The cells also express markers that are appropriate for this cell type.

Here we propose to generate these cells in high purity from hESCs and genetically modify them so that they can be induced to grow over inhibitory environments that exist in the injured spinal cord. We will then determine whether these human cells have the ability to regenerate the injured tissue in the spinal cord, and restore lost function. All of our studies will be conducted in an FDA-compliant manner, which will speed the translation of our results to humans if we are successful. The studies outlined in this proposal represent a novel approach to treating spinal cord injury, which might work for both acute and chronic injuries.

Statement of Benefit to California: 

This research plan will position California for international competitiveness in this emerging area of biotechnology, as our research strategy addresses critical scientific problems limiting the development of this sector in California and abroad. High purity cultures of hESC-derivatives enable transplantation approaches to disease, drug discovery, and predictive toxicology. This research plan will lead to the development and thorough characterization of a renewable source of human motor neurons that enables these 3 strategies as they pertain to acute spinal cord injury, chronic spinal cord injury, amyotrophic lateral sclerosis, polio, and spinal muscular atrophy. Clinically relevant scientific advance leads to the development of biotechnology companies, creating jobs and taxation. The treatment and care of individuals with disease or trauma-induced disorders of the central nervous system represents a significant economic burden to the State of California. If successful, our research plan will form the basis of a clinical strategy to improve the function and quality of life of spinal cord injured individuals, which may lessen the cost that the State bears in terms of patient care.

Progress Report: 
  • We have completed the first two AIMs of our proposal on time, and on budget, and we reported on these AIMs in our previous progress report. During this reporting period we have made progress on AIMs 3, 4 and 5. In AIM 3, we transplanted hESC-derived motor neuron progenitor cells into sites of motor neuron death in adult rats. We experienced minor technical difficulties that have set us back by a few months, due to sub-optimal expression of a growth factor in muscles, which is necessary to draw motor neuron axons out to muscles. We have fixed the problem and have confirmed long term growth factor expression in muscles. We have also confirmed that our toxin model induces motor neuron death using several methods, that transplanted motor neurons survive and connect with the spinal cord, and standardized all testing protocols to determine whether transplants along with growth factor addition to muscles will benefit the behavior of the treated animals. Our final experiment is in progress. This delay will not alter the project costs.
  • With regards to AIM 4, we are well ahead of schedule. This AIM was to begin in Year 3, but we began the experiments in Year 2. In this AIM, we transplanted hESC-derived motor neuron progenitor cells into sites of spinal cord injury in adult rats. We have confirmed that transplanted motor neurons survive and connect with the spinal cord, that transplantation enhances the survival of the host spinal cord that otherwise would have been lost, that transplantation enhances axon branching of the host spinal cord, and that these ‘nursing’ effects cause behavioral improvement of locomotion. Our increased productivity has not affected the budget.
  • With regards to AIM 5, are on track and on budget. We have generated FDA-compliant documents for all of the studies listed above.
  • We are on schedule with our research plan, having made progress on the last two AIMs of the proposal according to schedule. The goal of the 4th AIM was to transplant cells to the spinal cord of rats and see if they connect to muscle in the limbs that had been engineered to express an attractant for the processes of the cells in the spinal cord. We confirmed that we can induce the muscle in the limbs to express the attractant, and have the cells in the spinal cord survive, differentiate appropriately, become connected in the spinal cord to other circuits, and extend processes. In addition, we have evidence that these treatments benefit the locomotor ability of the rats. We wrote a scientific article concerning some of this work, and it was accepted for publication in an excellent journal. The goal of the 5th AIM was to document regulatory oversight for the project, to ensure compliance with FDA policies. We have generated FDA-compliant paperwork for all of our studies to date. Thus, our progress is in line with the original proposal.
  • This study tested the hypothesis that high purity motor neurons (MNs) derived from human embryonic stem cells could benefit spinal cord injury. In the first AIM, we proved that MNs could extend processes to muscle and cause it’s contraction, in a dish. In the second AIM, we proved that we could enhance process extension to muscle, in a dish. In the third and fourth AIMs, we proved that MNs transplanted into the diseased or injured spinal cord could integrate and benefit the function and spinal cord tissue structure of animals. In neither case did we see projection of MN processes to muscles, despite the provision of a MN process attractant in the muscles. Nonetheless, MN transplantation reduced tissue loss that normally results from injury or disease, and enhanced regeneration of the spinal cord and functional recovery of the animals.
Funding Type: 
Comprehensive Grant
Grant Number: 
RC1-00135
Investigator: 
ICOC Funds Committed: 
$2 566 701
Disease Focus: 
Multiple Sclerosis
Neurological Disorders
Stroke
Immune Disease
Stem Cell Use: 
Adult Stem Cell
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 

Strokes that affect the nerves cells, i.e., “gray matter”, consistently receive the most attention. However, the kind of strokes that affecting the “wiring” of the brain, i.e., “white matter”, cause nearly as much disability. The most severe disability is caused when the stroke is in the wiring (axons) that connect the brain and spinal cord; as many as 150,000 patients are disabled per year in the US from this type of stroke. Although oligodendrocytes (“oligos”) are the white matter cells that produce the lipid rich axonal insulator called myelin) are preferentially damaged during these events, stem cell-derived oligos have not been tested for their efficacy in preclinical (animal) trials. These same white matter tracts (located underneath the gray matter, called subcortical) are also the primary sites of injury in MS, where multifocal inflammatory attack is responsible for stripping the insulating myelin sheaths from axons resulting in axonal dysfunction and degeneration. Attempts to treat MS-like lesions in animals using undifferentiated stem cell transplants are promising, but most evidence suggests that these approaches work by changing the inflammation response (immunomodulation) rather than myelin regeneration. While immunomodulation is unlikely to be sufficient to treat the disease completely, MS may not be amenable to localized oligo transplantation since it is such a multifocal process. This has led to new emphasis on approaches designed to maximize the response of endogenous oligo precursors that may be able to regenerate myelin if stimulated. We hypothesize that by exploiting novel features of oligo differentiation in vitro (that we have discovered and that are described in our preliminary data) that we will be able to improve our ability to generate oligo lineage cells from human embryonic stem cells and neural stem cells for transplantation, and also to develop approaches to maximize oligo development from endogenous precursors at the site of injury in the brain. This proposal will build on our recent successes in driving oligo precursor production from multipotential mouse neural stem cells by expressing regulatory transcription factors, and apply this approach to human embryonic and neural stem cells to produce cells that will be tested for their ability to ameliorate brain damage in rodent models of human stroke. Furthermore, we hope to develop approaches that may facilitate endogenous recruitment of oligo precursors to produce mature oligos, which may prove a viable regenerative approach to treat a variety of white matter diseases including MS and stroke.

Statement of Benefit to California: 

Diseases associated with disruption of oligodendrocyte function and integrity (such as subcortical ischemic stroke and multiple sclerosis) are major causes of morbidity and mortality. Stroke is the third leading cause of death and the leading cause of permanent disability in the United States, costing over $50 billion dollars annually, as approximately 150,000 chronic stroke patients survive the acute event and are left with permanent, severe motor and/or sensory deficits. While much less common, multiple sclerosis (MS) is the primary non-traumatic cause of neurologic disability in young adults. Most patients are diagnosed in their 20s-40s and live for many decades after diagnosis with increasing needs for expensive services, medications and ultimately long-term care. Existing strategies for stem cell based therapies include both strategies to replace lost cells and to augment regeneration after injury, but most of these efforts have emphasized the role of undifferentiated stem cells in treatment despite the realization that the main nexus of injury in both diseases is frequently a differentiated cell type – the oligodendrocyte. This project will use new insights into the development of oligodendrocytes from the laboratories of the investigators to find ways to improve production of oligodendrocytes from human ES cells and human neural stem cells, test whether these cells can improve the clinical outcome in rodent models of stroke and MS after transplantation and search for new molecular treatments that would augment the regeneration of oligodendrocytes from resident brain stem cells after injury. This is the first step to translating the basic fundamental understanding of oligodendrocyte development into viable therapies for important human diseases that are major burdens on the citizens of California.

Progress Report: 
  • Over the last year we have succeeded in generating nearly pure cultures of human ES cell derived oligodendrocyte precursors from two different human ES cell lines. We are now also testing whether manipulation of transcription factors or morphogenic signaling pathways regulates the ability of these cells to differentiate into oligodendrocytes that produce myelin. We are testing these cells in a rodent stroke model to determine if they survive in the region of the stroke. If they survive, we will test whether they help to treat the strokes. We are also testing cells in transplantation into a developmental ischemia model and a model for genetic failure to produce myelin.
  • Our proposal centers on developing novel effective methods to generate oligodendrocytes from human ES cells. We focus on identifying signaling pathways (using studies in rodent neural stem cells) that can be adapted to human ES cells and used to regulate the efficiency of oligodendrocyte specification and differentiation from human ES cells. We then hope to use these human ES cell derived oligodendrocytes to determine whether transplantation of these cells is feasible in well characterized animal models associated with damage to oligodendrocytes. Over the last year we have made major progress toward these goals.
  • First, we have completed and submitted for publication two studies identifying the roles of Wnts and Sox10 in regulating the development of oligodendrocytes both during brain development and during stem cell differentiation in vitro. One of these papers is in the final stages of consideration after revision and the other is submitted awaiting reviews.
  • Second, we have developed a novel method for culturing human ES cell derived oligodendrocyte precursors. This is based on modifications of published methods but leads to greatly enhanced purity of final oligodendrocytes in our cultures (about 80% oligodendrocytes and 20% astrocytes). We have used this culture approach to address the role of sonic hedgehog in the differentiation of oligodendrocytes from human oligodendrocyte progenitors and have identified sonic hedgehog as a major regulator of oligodendrocyte differentiation and myelin production. This is quite distinct from rodent neural cells where sonic hedgehog doesn't appear to have this function. This will provide a novel therapeutic target to affect oligodendrocyte maturation and regeneration in disease models and will be of great utility for studying the function of mature human oligodendrocytes. This work is in preparation for submission.
  • Third, we have made some significant progress in our transplantation studies. We completed studies transplanting human ES derived oligodendrocyte progenitors into a rodent model of focal stroke and found that at 1 week post stroke and 2 weeks post stroke the survival of oligodendrocytes from these transplants is very minimal. Thus, we have discontinued this work because of this feasibility issue. We have moved on to examine studies of transplantation into newborn rodents with hypoxic injury and with dysmyelination becahse of the shiverer mutation. The progress here is good. The hypoxia model we are using is a chronic (up to 1 week) exposure to low oxygen tension of P2 mice, which is known to cause oligodendrocyte injury. We are initially characterizing the injury to oligodendrocytes at various durations of hypoxic exposure so that we can identify the best time point to transplant our cells into the brains. We are using immunodeficient mice to decrease the chances of rejection of the transplanted cells. In addition, we are generating a mouse colony with the shiverer allele combined with an immunodeficiency allele in order to be able to transplant cells in this model. In the meantime, we are determining the survival of transplanted cells into newborn mice to identify technical factors that will need to be overcome to allow efficient transplantation and to determine if our human cells participate in differentiation in these mice. Preliminarily we have found good survival of oligodendrocyte lineage cells after transplantation into P2 mice and the expression of myelin antigens after an appropriate period of development in vivo. This is very encouraging.
  • In the last year we have continued our efforts to transplant oligodendrocyte progenitors obtained by differentiation of human ES cells. Our progress in this area has been mixed because of substantial technical hurdles in consistent production of the oligodendrocyte progenitors from frozen stocks of cells. This will necessitate a no-cost extension for a small portion of the work to allow completion of the analysis of already transplanted animals.
  • We have made substantial progress as well in showing that these cells are capable of myelinating axons effectively in vitro. In addition, we've found that the human ES derived oligodendrocytes are capable of myelinating artificial nanofibers in vitro as well. This may serve as a useful platform in the future for drug discovery or other high throughput studies.
  • We have also identified an important novel molecular regulator of oligodendrocyte number and development and this work will continue into the future.
  • In this NCE period we were completing studies with animals that had received neonatal ischemic injury and were implanted with human ES cell derived cells of the oligodendrocyte lineage. These experiments showed that the cells survive and have oligodendrocyte lineage markers for three weeks post injection. Longer survival experiments are still ongoing.
Funding Type: 
Comprehensive Grant
Grant Number: 
RC1-00131
Investigator: 
ICOC Funds Committed: 
$2 445 716
Disease Focus: 
Spinal Cord Injury
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 

schemia-induced paraplegia often combined with a qualitatively defined increase in muscle tone (i.e. spasticity and rigidity) is a serious complication associated with a temporary aortic cross-clamping ( a surgical procedure to repair an aortic aneurysm). In addition to spinal ischemic injury-induced spasticity and rigidity a significant population of patients with traumatic spinal injury develop a comparable qualitative deficit i.e. debilitating muscle spasticity. At present there are no effective treatment which would lead to a permanent amelioration of spasticity and rigidity and corresponding improvement in ambulatory function. In recent studies, by using rat model of spinal ischemic injury we have demonstrated that spinal transplantation of rat or human neurons leads to a clinically relevant improvement in motor function and correlates with a long term survival and maturation of grafted cells. More recently we have demonstrated a comparable maturation of human spinal precursors grafted spinally in immunosupressed minipig. In the proposed set of experiments we wish to characterize a therapeutical potential of human blastocyst-derived neuronal precursors when grafted into previously ischemia- injured rat or minipig spinal cord. Defining the potency of spinally grafted hESC-derived neuronal precursors in two in vivo models of spinal ischemic injury serves to delineate the differences and/or uniformity in the cell maturation when cells are transplanted in 2 different animals species and can provide an important data set for future implications of such a therapies in human patients.

Statement of Benefit to California: 

Traumatic or ischemic spinal cord injury affect a significant number of people and in majority of cases can lead to a variable degree of motor dysfunction (such as paraparesis or paraplegia) and often combined with increased muscle tone (i.e. spasticity and rigidity). In contrast to other organ systems the central nervous system and spinal cord in particular has minimal or no neuron-regenerative capacity and therefore if a significant population of spinal cord neurons or fibers is lost the resulting deficit is permanent and irreversible. At present there is no effective therapy which would lead to a clinically relevant neurological improvement in patients with ischemia or trauma-induced paraplegia. Initial experimental data using paraplegic rats show that spinal grafting of rat or human neuronal precursors can provide a significant amelioration of spasticity and lead to improved ambulatory function. In the proposed set of experiments we wish to characterize a therapeutical potential of human blastocyst-derived neuronal precursors when grafted into previously ischemia- injured rat or minipig spinal cord. If proven effective such a treatment can potentially be used in patients with spinal ischemic paraplegia or in patients with other spinal injury-related dysfunction associated with a region-specific neuronal loss.

Progress Report: 
  • Transient spinal cord ischemia is a serious complication associated with aortic cross clamping (a surgical procedure required for the repair of aortic aneurysm). Neurological dysfunction resulting from transient spinal cord ischemia may be clinically expressed as paraparesis, fully-developed spastic paraplegia, or flaccid paraplegia. In spastic paraplegia, the underlying spinal pathology is characterized by a selective loss of inhibitory cells (neurons) in the ischemia-injured spinal cord. That loss of inhibition produces increased muscle tone (i.e. spasticity). While there are some current pharmacological treatments for spasticity that provide a certain degree of functional improvement, there are no effective therapies that lead to clinically-relevant, long-lasting recovery. One of the therapeutic approaches pursued by our group is the characterization of functional changes after spinal cord transplantation of neuronal cells previously generated in culture with the goal of replacing missing inhibitory neurons in the spinal cord. In our recent experiments, we characterized the survival and differentiation of human embryonic stem cell-derived neural precursors that were grafted into the spinal cord of rats with a previous spinal ischemic injury. Our initial data demonstrate that spinal grafting of neural precursors generated from 3 independent human embryonic stem cell lines is associated with long-term cell engraftment of grafted cells. A significant population of the grafted cells displayed neuronal differentiation, progressive maturation, and expression of markers which are typical for mature, functional human neurons. Initial analysis of grafted cells also indicated the development of functional connectivity between transplanted neurons and surviving neurons of the recipient. A significant advancement in our effort to characterize the effect of such a treatment was the use of a sorting technique which permits the generation of large quantities of highly-purified neural precursors. The capacity to generate such large quantities of pure cell populations is particularly important in our large preclinical animal model (minipig), which is essential to move this therapeutic approach to clinic. In addition, we characterized an efficient cell freezing protocol. The sorting and freezing techniques together allow large quantities of identical cell populations to be frozen for future transplantation, ensuring a group of animals receives an identical cell population. Our plan for the next year is to perform long-term functional recovery studies in our minipig model of spinal ischemia.
  • Transient spinal cord ischemia is a serious complication associated with aortic cross clamping, i.e., the procedure required to replace aortic aneurysm. The major neurological deficit resulting from spinal ischemic injury is the loss of motor function in lower extremities, also called paraplegia. The pathological mechanism leading to the loss of function is the result of progressive death of spinal cells (i.e., neurons) in the affected region of the spinal cord. At present there is no effective therapy for spinal ischemia-induced paraplegia.
  • In our previous completed studies, we have characterized the survival and neuronal maturation of human embryonic stem cell derived neural precursors analyzed at 2 weeks to 2 months after spinal transplantation in spinal ischemia-injured rats. A comparable survival and maturation was seen compared to fetal human spinal cord-derived cells. In our next studies, we will define the therapeutic potency of spinally grafted ES-NPCs once cells are grafted into the spinal cord of immunodeficient rats (i.e., animals which do not require immunosuppression) and the effect of cell grafting assessed for up to 4 months after cell transplantation. In subsequent studies, the degree of treatment effect will be studied in continuously immunosuppressed minpigs with previous spinal ischemic injury.
  • Transient spinal cord ischemia is a serious complication associated with aortic cross clamping, i.e., the procedure required to replace aortic aneurysm. The major neurological deficit resulting from spinal ischemic injury is the loss of motor function in the lower extremities, also called paraplegia. The pathological mechanism leading to the loss of function is the result of progressive death of spinal cells (i.e., neurons) in the affected region of the spinal cord. At present there is no effective therapy for spinal ischemia-induced paraplegia. In our previous completed studies, we have characterized the survival and neuronal maturation of human embryonic stem cell-derived neural precursors grafted into the lumbar spinal cord in immunodeficient rats and have demonstrated good tolerability of long-term immunosuppression in rodents and minipigs after using subcutaneously implanted tacrolimus pellets. In our ongoing studies, our goal is to characterize the effect of clonally expanded embryonic stem cell-derived neural precursors after spinal grafting in long-term immunosuppressed rats and minipigs and immunodeficient rats with previous spinal ischemic injury.
Funding Type: 
Comprehensive Grant
Grant Number: 
RC1-00125
Investigator: 
ICOC Funds Committed: 
$3 035 996
Disease Focus: 
Parkinson's Disease
Neurological Disorders
Stroke
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
Cell Line Generation: 
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 

Understanding differentiation of human embryonic stem cells (hESCs) provides insight into early human development and will help directing hESC differentiation for future cell-based therapies of Parkinson’s disease, stroke and other neurodegenerative conditions.

The PI’s laboratory was the first to clone and characterize the transcription factor MEF2C, a protein that can direct the orchestra of genes to produce a particular type of cell, in this case a nerve cell (or neuron). We have demonstrated that MEF2C directs the differentiation of mouse ES cells into neurons and suppresses glial fate. MEF2C also helps keep new nerve cells alive, which is very helpful for their successful transplantation. However, little is known about the role of MEF2C in human neurogenesis, that is, its ability to direct hESC differentiation into neuronal lineages such as dopaminergic neurons to treat Parkinson’s disease and its therapeutic potential to promote the generation of nerve cells in stem cell transplantation experiments. The goal of this application is to fill these gaps.

The co-PI’s laboratory has recently developed a unique procedure for the efficient differentiation of hESCs into a uniform population of neural precursor cells (NPCs), which are progenitor cells that develop from embryonic stem cells and can form different kinds of mature cells in the nervous system. Here, we will investigate if MEF2C can instruct hESC-derived NPCs to differentiate into nerve cells, including dopaminergic nerve cells for Parkinson’s disease or other types of neurons that are lost after a stroke. Moreover, we will transplant hESC-NPCs engineered with MEF2C to try to treat animal models of stroke and Parkinson’s disease. We will characterize known and novel MEF2C target genes to identify critical components in the MEF2C transcriptional network in the clinically relevant cell population of hESC-derived neural precursor cells (hESC-NPCs).

Specifically we will: 1) determine the function of MEF2C during in vitro neurogenesis (generation of new nerve cells) from hESC-NPCs; 2) investigate the therapeutic potential of MEF2C engineered hESC-NPCs in Parkinson’s and stroke models; 3) determine the MEF2C DNA (gene) binding sites and perform a “network” analysis of MEF2C target genes in order to understand how MEF2C works in driving the formation of new nerve cells from hESCs.

Statement of Benefit to California: 

Efficient and controlled neuronal differentiation from human embryonic stem cells (hESCs) is mandatory for developing future clinical cell-based therapies. Strategies to direct differentiation towards neuronal vs. glial fate are critical for the development of a uniform population of desired neuronal specificities (e.g., dopaminergic neurons for Parkinson’s disease (PD)). Our laboratory was the first to clone and characterize the transcription factor MEF2C, the major isoform of MEF2 found in the developing brain. Based on our encouraging preliminary results that were obtained with mouse (m)ESC-derived and human fetal brain-derived neural precursors, we propose to investigate if MEF2C enhances neurogenesis from hESCs. In addition to neurogenic activity, we have shown that MEF2C exhibits an anti-apoptotic (that is, anti-death) effect and therefore increases cell survival. This dual function of MEF2C is extremely valuable for the purpose of transplantation of MEF2C-engineererd neural precursors. Additionally, we found MEF2 binding sites in the Nurr1 promoter region, which in the proper cell context, should enhance dopaminergic (DA) neuronal differentiation. We hypothesize that hESC-derived neural precursors engineered with MEF2C will selectively differentiate into neurons, which will be resistant to apoptotic death and not form tumors such as teratomas.

We believe that our proposed research will lead us to a better understanding of the role of MEF2C in hESC differentiation to neurons. These results will lead to novel and effective means to direct hESCs to become neurons and to resist cell death. This information will ultimately lead to novel, stem cell-based therapies to treat stroke and neurodegenerative diseases such as Parkinson’s.

We also believe that an effective, straightforward, and broadly understandable way to describe the benefits to the citizens of the State of California that will flow from the stem cell research we propose to conduct is to couch the work in the familiar, everyday business concept of “Return on Investment.” The novel therapies and reconstructions that will be developed and accomplished as a result of our research program and the many related programs that will follow will provide direct benefits to the health of California citizens. In addition, this program and its many complementary programs will generate potentially very large, tangible monetary benefits to the citizens of California. These financial benefits will derive directly from two sources. The first source will be the sale and licensing of the intellectual property rights that will accrue to the state and its citizens from this and the many other stem cell research programs that will be financed by CIRM. The second source will be the many different kinds of tax revenues that will be generated from the increased bio-science and bio-manufacturing businesses that will be attracted to California by the success of CIRM.

Progress Report: 
  • In Year 02 of this grant, we have continued to refine the techniques developed for producing nerve cells from human embryonic stem cells (hESC). Central to our grant proposal is the expression of an active form of a protein called MEF2C, which we insert into the stem cells at a young age. MEF2C is a transcription factor, which is a molecule that regulates how RNA is converted to a protein. MEF2C regulates the production of proteins that are specifically found in neurons, and it plays an important role in making a stem cell into a nerve cell. Specific improvements this year in culture conditions have resulted in our being able to direct a much higher percentage of hESCs into precursors of nerve cells, and it is at this stage that the cells are most appropriate for insertion of MEF2C. Following this, we can transplant the stem cells, destined to become nerve cells, in to the brain in rodent models of stroke and Parkinson’s disease. We have also made very good progress in producing dopaminergic nerve cells, the specific type of cell that dies in Parkinson’s disease. In addition, our improved methods are completely free of any animal products, so they represent a step forward in developing cells as a treatment for human diseases.
  • Building upon these advances in our techniques, we have transplanted cells into a rat model of Parkinson’s disease and shown that a large percentage of the cells become dopaminergic nerve cells in the brain. Additionally, rats receiving these cell transplants show greater improvements in motor skills compared to rats receiving similar cells without the inserted MEF2C factor. These findings complement our results presented in the first year’s progress report showing that transplantation of these MEF2C-expressing cells into a mouse model of stroke resulted in less damage to the brain. Together these results indicate the utility and versatility of these cells “programmed” by expression of the inserted MEF2C gene.
  • Finally, in Year 02 we report on our efforts to discover the mechanism by which the MEF2C gene prevents cell death and drives stem cells to become nerve cells. We have performed microarray analyses, which measure the expression levels of various genes, e.g., how much of each protein is produced from a gene. This approach includes 24,000 of the possible ~30,000 gene sequences expressed in human cells and tissues. These experiments were performed on stem cells with the inserted MEF2C gene just as the cells were making the decision to become a nerve cell. We observed a decrease in the activity of several genes that are known to make stem cells proliferate (divide and multiply), rather than becoming a differentiated nerve cell. This finding is consistent with the known role of MEF2C, which causes cells to stop proliferating and start differentiating into nerve cells. Without insertion of MEF2C into the stem cells, they mostly continue proliferating. We also saw that many genes, which are not expressed in mature nerve cells, were coordinately down regulated. These results may suggest a new role of MEF2C as a factor for shutting down gene expression, thereby helping to promote the formation of new nerve cells. We are continuing our investigations into the mechanism of MEF2C actions in neuronal differentiation and function as well as our transplantation experiments in stroke and Parkinson’s disease models in the coming year.
  • We initially discovered that mouse embryonic stem cell (ESC)-derived neural progenitor cells forced to express the transcription factor MEF2C were protected from dying and were also given signals to differentiate almost exclusively into neurons (J Neurosci 2008; 28:6557-68). Under the CIRM grant, we have investigated the role of MEF2C and consequences of its forced expression in neural differentiation of human ES cells, including identification of specific genes under MEF2C regulation. We have also used rodent models of Parkinson’s disease and stroke to evaluate the therapeutic potential of human ESC-derived neural progenitors forced to express active MEF2C (MEF2CA).
  • In the third year of the CIRM grant, we continued to refine our procedures for differentiating MEF2CA-expressing human ES cells growing in culture into neural progenitor cells (NPC) and fully developed neurons. We also investigated their electrophysiological characteristics and potential to develop into specific types of neurons. We found that not only do the MEF2CA-expressing NPCs become almost exclusively neurons, as we previously showed, but they also had a strong bias to develop into dopaminergic neurons, the type of neuron that dies in Parkinson’s disease. We also found that MEF2CA-expressing NPCs differentiated to maturity in culture dishes showed a wide variety of electrophysiological responses of normal mature neurons. We were able to record sodium currents and action potentials indicating that the neurons were capable of transmitting chemo-electrical signals. They also responded to GABA and NMDA (a glutamate mimic), which shows that the neurons can respond to the major signal-transmitting molecules in the brain.
  • Previously we showed that transplantation of the MEF2CA-expressing human ESC-derived NPCs into the brains of a rat model of Parkinson’s disease resulted in a much higher number of dopaminergic (DA) neurons and positive behavioral recovery compared to controls. We now report that evaluation of the MEF2CA-expressing cells showed a much higher expression level of a variety of proteins known to be important in DA neuron differentiation and that none of these cells become tumors or hyper proliferative. We have also transplanted NPCs into the brains of a rat stroke model. Our preliminary data analysis shows an improvement in the ability to walk a tapered beam in the rats transplanted with MEF2CA-expressing cells compared to controls. These results are evidence there may be a great advantage in the use of NPC expressing MEF2C for transplantation into various brain diseases and injuries.
  • We have also continued our investigations into the mechanisms of MEF2C activities in the hope of finding new drug targets to mimic it effects. We have identified interactive pathways in which MEF2C plays a role and found correlations between MEF2C expression levels and a variety of diseases. These will hopefully lead us to a better understanding of how to leverage our results to produce effective therapies for a broad spectrum of neurological diseases and traumas.
  • Our goals for this grant were to determine the role of the transcription factor MEF2C in neurogenesis, including all of the targets of this factor in the genome, use this knowledge to direct differentiation of human embryonic stem cells (hESC) into specific types of neurons, and investigate the transplantation of these cells into rodent models of Parkinson’s disease (PD) and stroke. During the tenure of this grant, we accomplished these goals to a very significant degree. Our investigations into the role of MEF2C in neurogenesis produced a large body of knowledge pertinent to its essential role in this process. This knowledge base was achieved through both monitoring expression levels of MEF2C during the entire process of neurogenesis and by knocking down its expression by use of siRNA. We now have a very detailed view of the temporal contribution of MEF2C as stem cells differentiate into neurons. Using this knowledge, we optimized a differentiation protocol for directing hESC into neuronal precursor cells and then initiated expression of a constitutively active MEF2 transcription factor (MEF2CA) via lentiviral technology. We discovered that the forced expression of MEF2CA provided a strong bias to neurons to differentiate along a dopaminergic (DA) lineage. Our network analysis for MEF2C confirmed that many of the known effector proteins for DA neurons are indeed targets for this transcription factor. Histological and electrophysiological investigations into the nature of these cells grown in vitro showed that they are indeed functional neurons displaying the anticipated qualities during the various stages of differentiation.
  • Our in vivo transplantation studies have been equally productive. Owing to the strong tendency of the MEF2CA-expressing cells to differentiate into DA neurons, we first investigated their effects on a rat PD model where the dopaminergic cells of the substantia nigra are ablated on one side of the brain by injection of 6-hydroxydopamine. In response to an injection of the dopamine analog apomorphine, these rats will turn in a circle and the readout is the number of turns in a 30 minute period measured on a rotometer. Fewer turns indicate that the rat has less pathology, i.e., is getting better. We transplanted hESC-derived neural progenitor cells (hESC-NPC) either expressing MEF2CA or not and monitored recovery of the rats. While rats receiving both preparations of stem cells showed considerable improvement, the ones receiving MEF2C-expressing cells did significantly better on the rotometer. Also, histologically the MEF2CA-expressing cells could all be seen to differentiate, whereas those that did not express MEF2CA were often found in an undifferentiated state, which potentially posses a problem of continuing proliferation in the brain and tumor formation. Thus, the forced expression of MEF2CA forced the cells to differentiate and prevented uncontrolled cell division. An additional advantage was that the remaining endogenous DA neurons showed much greater density of fibers in the vicinity of the transplanted cells, suggesting that there was an additional benefit of factor secretion. Thus, the MEF2CA genetically modified cells appear to have significant advantages for transplantation for PD.
  • We are also investigating the use of the MEF2CA-expressing hESC-NPC in rat and mouse models of stroke. Preliminary data shows that in both systems we see behavioral improvements following the transplantations with these cells. In the period of the no cost extension, we will complete these studies and characterize the types of neurons these transplanted cells become and their role in reversing the pathology caused by the brain ischemia from stroke. Our hypothesis is that there is a strong bias toward the DA neuron phenotype produced by the expression of MEF2CA, but that this is overridden by the context within the brain. Therefore, in a stroke model, the context of damage to the cortex provides signals to the newly transplanted cells that they should migrate to the damaged area and become cells appropriate to that region, not DA neurons. We will test this hypothesis in the remaining months of the grant.
  • Our goals for this grant were to determine the role of the transcription factor MEF2C in neurogenesis, including all of the targets of this factor in the genome, use this knowledge to direct differentiation of human embryonic stem cells (hESC) into specific types of neurons, and investigate the transplantation of these cells into rodent models of Parkinson’s disease (PD) and stroke. During the tenure of this grant, we accomplished these goals to a very significant degree. Our investigations into the role of MEF2C in neurogenesis produced a large body of knowledge pertinent to its essential role in this process. This knowledge base was achieved through both monitoring expression levels of MEF2C during the entire process of neurogenesis and by knocking down its expression by use of siRNA. We now have a very detailed view of the temporal contribution of MEF2C as stem cells differentiate into neurons. Using this knowledge, we optimized a differentiation protocol for directing hESC into neuronal precursor cells and then initiated expression of a constitutively active MEF2 transcription factor (MEF2CA) via lentiviral technology. We discovered that the forced expression of MEF2CA provided a strong bias to neurons to differentiate along a dopaminergic (DA) lineage. Our network analysis for MEF2C confirmed that many of the known effector proteins for DA neurons are indeed targets for this transcription factor. Histological and electrophysiological investigations into the nature of these cells grown in vitro showed that they are indeed functional neurons displaying the anticipated qualities during the various stages of differentiation.
  • Our in vivo transplantation studies have been equally productive. Owing to the strong tendency of the MEF2CA-expressing cells to differentiate into DA neurons, we first investigated their effects on a rat PD model where the dopaminergic cells of the substantia nigra are ablated on one side of the brain by injection of 6-hydroxydopamine. In response to an injection of the dopamine analog apomorphine, these rats will turn in a circle and the readout is the number of turns in a 30 minute period measured on a rotometer. Fewer turns indicate that the rat has less pathology, i.e., is getting better. We transplanted hESC-derived neural progenitor cells (hESC-NPC) either expressing MEF2CA or not and monitored recovery of the rats. While rats receiving both preparations of stem cells showed considerable improvement, the ones receiving MEF2C-expressing cells did significantly better on the rotometer. Also, histologically the MEF2CA-expressing cells could all be seen to differentiate, whereas those that did not express MEF2CA were often found in an undifferentiated state, which potentially posses a problem of continuing proliferation in the brain and tumor formation. Thus, the forced expression of MEF2CA forced the cells to differentiate and prevented uncontrolled cell division. An additional advantage was that the remaining endogenous DA neurons showed much greater density of fibers in the vicinity of the transplanted cells, suggesting that there was an additional benefit of factor secretion. Thus, the MEF2CA genetically modified cells appear to have significant advantages for transplantation for PD.
  • We are also investigating the use of the MEF2CA-expressing hESC-NPC in rat and mouse models of stroke. Preliminary data shows that in both systems we see behavioral improvements following the transplantations with these cells. In the period of the no cost extension, we will complete these studies and characterize the types of neurons these transplanted cells become and their role in reversing the pathology caused by the brain ischemia from stroke. Our hypothesis is that there is a strong bias toward the DA neuron phenotype produced by the expression of MEF2CA, but that this is overridden by the context within the brain. Therefore, in a stroke model, the context of damage to the cortex provides signals to the newly transplanted cells that they should migrate to the damaged area and become cells appropriate to that region, not DA neurons. We will test this hypothesis in the remaining months of the grant.
Funding Type: 
Comprehensive Grant
Grant Number: 
RC1-00116
Investigator: 
ICOC Funds Committed: 
$2 512 664
Disease Focus: 
Aging
Alzheimer's Disease
Neurological Disorders
Genetic Disorder
Stem Cell Use: 
Embryonic Stem Cell
iPS Cell
Cell Line Generation: 
Embryonic Stem Cell
iPS Cell
oldStatus: 
Closed
Public Abstract: 

Alzheimer’s Disease (AD) is a progressive incurable disease that robs people of their memory and ability to think and reason. It is emotionally, and sometimes financially devastating to families that must cope when a parent or spouse develops AD. Unfortunately, however, we currently lack an understanding of Alzheimer’s Disease (AD) that is sufficient to drive the development of a broad range of therapeutic strategies. Compared to diseases such as cancer or heart disease, which are treated with a variety of therapies, AD lacks even one major effective therapeutic approach. A key problem is that there is a paucity of predictive therapeutic hypotheses driving the development of new therapies. Thus, there is tremendous need to better understand the cellular basis of AD so that effective drug and other therapies can be developed. Several key clues come from rare familial forms of AD (FAD), which identify genes that can cause disease when mutant and which have led to the leading hypotheses for AD development. Recent work on Drosophila and mouse models of Alzheimer’s Disease (AD) has led to a new suggestion that early defects in the physical transport system that is responsible for long-distance movements of vital supplies and information in neurons causes neuronal dysfunction. The type of neuronal failure caused by failures of the transport systems is predicted to initiate an autocatalytic spiral of biochemical events terminating in the classic pathologies, i.e., plaques and tangles, and the cognitive losses characteristic of AD. The problem, however, is how to test this new model and the prevailing “amyloid cascade” model, or indeed any model of human disease developed from studies in animal models, in humans. It is well known that mouse models of AD do not fully recapitulate the human disease, perhaps in part because of human-specific differences that alter the details of the biochemistry and cell biology of human neurons. One powerful approach to this problem is to use human embryonic stem cells to generate human neuronal models of hereditary AD to test rigorously the various hypotheses. These cellular models will also become crucial reagents for finding and testing new drugs for the treatment of AD.

Statement of Benefit to California: 

Alzheimer’s Disease (AD) is emotionally devastating to the families it afflicts as well as causing substantial financial burdens to individuals, to families, and to society as a whole. In California, the burden of Alzheimer’s Disease is substantial, so that progress in the development of therapeutics would make a significant financial impact in the state. Although there are not a great deal of data about the burden of AD in California specifically, the population of California is 12% of that of the United States and most information suggests that California has a “typical” American burden of this disease. For example, information from the Alzheimer’s Association (http://www.alz.org/alzheimers_disease_alzheimer_statistics.asp) reveals: 1) An estimated 4.5 million Americans have Alzheimer’s disease, which has more than doubled since 1980. This creates an estimated nationwide financial burden of direct and indirect annual costs of caring for individuals with AD of at least $100 billion. Thus, a reasonable estimate is that California has more than half a million AD patients with an estimated cost to California of $12 billion per year! 2) One in 10 individuals over 65 and nearly half of those over 85 are affected, which means that as our population ages, we will be facing a tidal wave of AD. Current estimates are that with current rates of growth that the AD patient population will double or triple in the next 4 decades. 3) The potential benefit of research such as that proposed in this grant application is that finding a treatment that could delay onset by five years could reduce the number of individuals with Alzheimer’s disease by nearly 50 percent after 50 years. This would be significant since a person with Alzheimer’s disease will live an average of eight years and as many as 20 years or more from the onset of symptoms. Finding better treatments will thus have significant financial benefits to California. 4) After diagnosis, people with Alzheimer’s disease survive about half as long as those of similar age without AD or other dementia. 5) In terms of financial impact on California families, the statistics (http://www.alz.org/alzheimers_disease_alzheimer_statistics.asp) are that more than 7 out of 10 people with Alzheimer’s disease live at home. Almost 75 percent of their care is provided by family and friends. The remainder is “paid’ care costing an average of $19,000 per year. Families pay almost all of that out of pocket. The average cost for nursing home care is $42,000 per year but can exceed $70,000 per year in some areas of the country. The average lifetime cost of care for an individual with Alzheimer’s is $174,000. Thus, any progress in developing better therapy for AD will have a substantial positive impact to California.

Progress Report: 
  • We have made significant progress on developing human stem cell based systems to probe the causes and features of Alzheimer's Disease. We are focusing on using human embryonic and human pluripotent stem cell lines carrying genetic changes that cause hereditary Alzheimer's Disease (AD). In one approach, we have made progress by developing iPS cells carrying small genetic changes in the presenilin 1 gene, which cause severe early onset AD. We also made substantial progress on developing methods to measure the distribution within neurons of products linked to Alzheimer's Disease. Finally, we have completed development of a cell sorting method to purify neuronal stem cells, neurons, and glia from human embryonic stem cells and human IPS cells. Together, these methods should allow us to continue making progress on using pluripotent human stem cells to probe the molecular basis for how cellular changes found in neurons in the brain of AD patients are generated. In addition, these methods we are developing are moving us closer to having sources of normal and AD human neurons generated in the laboratory for drug-testing and development.
  • We continue to make significant progress developing human stem cell based disease models to probe the causes of Alzheimer's Disease (AD) and to eventually develop drugs. In the past year we generated and analyzed several new human pluripotent stem cell lines (hIPS) carrying genetic changes that cause hereditary AD or that increase the risk of developing AD. We detected AD related characteristics in neurons with hereditary and in one case of a sporadic genetic type. While considerable confirmatory work needs to be done, our data raise the possibility that AD can be modeled in human neurons made from hIPS cells. In the coming year, we hope to continue making progress on using pluripotent human stem cells to probe the molecular basis for how cellular changes found in neurons in the brain of AD patients are generated. In addition, the methods we are developing are moving us closer to having sources of normal and AD human neurons generated in the laboratory for drug-testing and development.
  • In our final year of funding, we made significant progress developing human stem cell based disease models to probe the causes of Alzheimer's Disease (AD) and to eventually develop drugs. We generated and analyzed several new human pluripotent stem cell lines (hIPS) carrying genetic changes that cause hereditary AD or that increase the risk of developing AD. We detected AD related characteristics in neurons with hereditary and in one case of a sporadic genetic type. While considerable confirmatory work needs to be done, our data raise the possibility that AD can be modeled in human neurons made from hIPS cells. The methods we developed are moving us closer to having sources of normal and AD human neurons generated in the laboratory for drug-testing and development.
Funding Type: 
Comprehensive Grant
Grant Number: 
RC1-00115
Investigator: 
Name: 
Type: 
PI
ICOC Funds Committed: 
$2 879 210
Disease Focus: 
Amyotrophic Lateral Sclerosis
Neurological Disorders
Parkinson's Disease
Genetic Disorder
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 

Human embryonic stem cells (hESCs) are pluripotent entities, capable of generating a whole-body spectrum of distinct cell types. We have developmental procedures for inducing hESCs to develop into pure populations of human neural stem cells (hNS), a step required for generating authentic mature human neurons. Several protocols have currently been developed to differentiate hESCs to what appear to be differentiated dopaminergic neurons (important in Parkinson’s disease (PD) and cholinergic motor neurons (important in Amyolateral Sclerosis (ALS) in culture dishes. We have developed methods to stably insert new genes in hESC and we have demonstrated that these transgenic cells can become mature neurons in culture dishes. We plan to over express alpha synuclein and other genes associated with PD and superoxide dismutase (a gene mutated in ALS) into hESCs and then differentiate these cells to neurons, and more specifically to dopaminergic neurons and cholinergic neurons using existing protocols. These transgenic cells can be used not only for the discovery of cellular and molecular causes for dopaminergic or cholinergic cell damage and death in these devastating diseases, but also can be used as assays to screen chemical libraries to find novels drugs that may protect against the degenerative process. Until recently the investigation of the differentiation of these human cells has only been observed in culture dishes or during tumor formation. Our recent results show that hESC implanted in the brains of mice can survive and become active functional human neurons that successfully integrate into the adult mouse forebrain. This method of transplantation to generate models of human disease will permit the study of human neural development in a living environment, paving the way for the generation of new models of human neurodegenerative and psychiatric diseases. It also has the potential to speed up the screening process for therapeutic drugs.

Statement of Benefit to California: 

We plan to develop procedures to induce human ES cells into mature functioning neurons that carry genes that cause the debilitating human neurological diseases, Parkinson’s disease and Amyolateral Sclerosis (ALS). We will use the cells to reveal the genes and molecular pathways inside the cells that are responsible for how the mutant genes cause damage to specific types of brain cells. We also will make the cells available to other researchers as well as biotech companies so that other investigators can use these cells to screen small molecule and chemical libraries to discover new drugs that can interfere with the pathology caused by these mutant cells that mimic human disease, in hopes of accelerating the pace of discovery.

Progress Report: 
  • Our research is focused on studying two debilitating diseases of the nervous system: Parkinson’s disease (PD) and Amyotrophic Lateral Sclerosis (ALS) also known as Lou Gehrig’s disease. While the causes and symptoms of these two conditions are very different, they share one aspect in common: patients gradually lose specific types of nerve cells, namely the so-called dopaminergic neurons in PD, and motor neurons in ALS. If we can find ways to protect the neurons from dying, we might be able to slow or even halt disease progression in ALS and PD patients. In the past two years, our lab has developed robust procedures to generate these two classes of neurons from human embryonic stem cells and we have been studying the molecular changes that govern their specialization. Since last year, we have been using neurons to elucidate the molecular mechanisms that underlie the demise of these cells.
  • ALS is one of the most common neuromuscular diseases, afflicting more than 30,000 Americans. Patients rapidly lose their motor neurons – the nerve cells that extend from the brain through the spinal cord to the muscles, thereby controlling their movement. Therapy options are extremely limited and people with ALS usually succumb to respiratory failure or pneumonia within three to five years from the onset of symptoms. Most ALS patients have no family history of ALS and carry no known genetic defects that may help explain why they develop the disease. However, a small number of ALS patients have mutations in the superoxide dismutase 1 (SOD1) gene, which encodes an enzyme that scavenges so-called free radicals – aggressive oxidizing molecules that are by-products of the cells’ normal metabolism. Researchers therefore believe that accumulation of these free radicals may damage motor neurons in ALS and contribute to their death.
  • To test this idea, we introduced the mutated form of the SOD1 gene into astrocytes – cells that provide metabolic and structural support to neurons – and cultured our stem cell-derived motor neurons along with these SOD1-mutant astrocytes. Indeed, while motor neurons grown on ‘normal’ astrocytes were fully viable, we saw widespread death of motor neurons in cocultures with ‘mutant’ astrocytes, along with elevated levels of free radicals. We think that this is due to our mutant astrocytes being causing inflammation, and so our future efforts are focused on understanding the role of the immune system, specifically the function of microglia – the resident immune cells of the brain and spinal cord – in our co-cultures with human motor neurons. We are very excited about these results because they show that our cocultures may be a very useful tool to screen drugs that may counteract the neurotoxicity caused by inflammation and free radicals. We have already begun testing several known antioxidants, and found some of them to be very effective in improving motor neuron survival in the culture dish. Such compounds may ultimately improve the condition of ALS patients.
  • PD is the second most common neurodegenerative disease and develops when neurons in the brain, and in particular, in a part of the brain known as the substantia nigra die. These neurons are called dopaminergic because they produce dopamine, a molecule that is necessary for coordinated body movement. Many dopaminergic neurons are already lost when patients develop PD symptoms, which include trembling, stiffness, and slow movement. Around one million Americans are currently suffering from PD, and 60,000 new cases are diagnosed each year. While several surgical and pharmacological treatment options exist, they cannot slow or halt disease progression and are instead aimed at treating the symptoms. The exact causes for neuron death in PD are unknown but among others inflammation in the affected brain area may play a role in disease progression.
  • In a joint effort with the laboratories of Christopher Glass and Michael Rosenfeld at the University of California, San Diego, we showed using animal experiments that a protein called Nurr1 is crucial for the development and survival of dopaminergic neurons. We found that the Nurr1 gene is turned on by inflammatory signals and suppresses genes that encode neurotoxic factors. Microglia are the major initiators of the neurotoxic response to inflammatory stimuli, which is then amplified by astrocytes. Thus our findings reveal an important role for Nurr1 in microglia and astrocytes to protect dopaminergic neurons from exaggerated production of inflammation-induced neurotoxic mediators. We are now using human embryonic stem cell-derived dopaminergic neurons, cultured along with human atrocytes and microglia to test whether we can demonstrate this positive role of Nurr1 in a culture dish as well.
  • We are investigating the molecular mechanisms underlying two major neurological diseases: Parkinson’s disease (PD) and Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s disease. In the past year, we have taken our previously developed human embryonic stem cell (hESC)-based cell culture model for PD and ALS another step further: we have begun building an assay system that may eventually allow both the identification of biomarkers for early diagnosis and the screening of drug candidates for ALS and PD. By transplanting hESC-derived neurons into live animals and brain slices, we have also made first inroads into recapitulating the disease processes in animal model systems.
  • While the causes and symptoms of ALS and PD are very different, they share one aspect in common: in both, patients gradually lose specific types of nerve cells, namely, the so-called dopaminergic neurons in PD, and motor neurons in ALS; it this neuron death that causes both diseases. Previously, we showed with our hESC-based cell culture system that an inflammatory response in astrocytes (the brain cells that provide metabolic and structural support to neurons) is involved in loss of motor neurons. Similarly, we demonstrated that microglia (the brain’s immune cells) and astrocytes together protect dopaminergic neurons from exaggerated production of inflammation-induced neurotoxic mediators. This function of astrocytes and microglia was dependent on a protein called Nurr1: we found that the Nurr1 gene is turned on by inflammatory signals and suppresses genes that encode neurotoxic factors.
  • We have now begun to characterize in depth the specific signaling molecules that communicate the inflammation cue from the glial cells to neurons. To do this, we cultured astrocytes and microglia in the petri dish, induced inflammation and collected cell culture supernatants from the ‘inflamed’ and normal cells. We then measured the levels of specific so-called cytokines, the inflammatory signaling molecules secreted by the glial cells. Once we have obtained a characteristic cytokine ‘signature’ of disease-associated glial cells, we can begin to unravel the molecular pathways that lead to inflammation. Thus our research may lead to the discovery of early diagnostic markers and enable drug screening for compounds that suppress or prevent these neurotoxic inflammatory processes.
  • Our cell culture assays have provided a great deal of insight into the signaling cascades that eventually lead to neuron death. However, they probably cannot fully recapitulate the complex interplay between the neurons and the cellular environment in which they reside within the brain. We have therefore begun to transplant hESC-derived neurons into the brains of mice. Our results indicate that the neurons rapidly extended processes and developed dendritic branches and axons that integrated into the existing neuronal network. In the coming year, we plan to build on these results, using our hESC-derived neuronal models of PD and ALS to better understand mechanisms of dysregulation. Specifically, we will examine alterations in synapse formation, cell survival, and neuron maturation. We will also devise strategies for functional recovery and rescue in the context of the living animal.
  • We are investigating the molecular mechanisms underlying two major neurological diseases: Parkinson’s disease (PD) and Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s disease. In the past year, we took our human embryonic stem cell (hESC)-based neural cell culture model for PD and ALS another step further and built sensitive and quantitative assays that can allow for the screening of drug candidates for ALS and PD. We have also consistently improved our transplanting techniques and are now able to detect functional, electrophysiologically active, hESC-derived neurons in live animals. This experiment was crucial to show that, under our culture conditions, human neurons derived from embryonic stem cells were able to integrate and form meaningful connections with other neurons in a given adult brain environment.
  • Moreover, we are now performing an in-depth characterization of the specific signaling molecules that communicate the inflammation cues from the glial cells to neurons in the presence of ALS-causing mutations (SOD1G37R) and PD-causing mutations (recombinant alfa-synuclein). In this report we have explored another functional assay to measure glial function and inflammatory response using astrocytes that express ALS-causing mutations. In addition, we report here that adding PD-causing mutagens to mixed cultures of human neurons and astrocytes results in the death of dopaminergic neurons, the type of neurons affected in PD. We are currently testing new compounds that can decrease the neuronal toxicity observed.
  • Our research may not only lead to the discovery of early diagnostic markers but also enable drug screening for compounds that suppress or prevent these neurotoxic inflammatory processes.

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