Huntington's Disease

Coding Dimension ID: 
310
Coding Dimension path name: 
Neurological Disorders / Huntington's Disease

New Cell Lines for Huntington's Disease

Funding Type: 
New Cell Lines
Grant Number: 
RL1-00678
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.

Use of human iPSC-derived neurons from Huntington’s Disease patients to develop novel, disease-modifying small molecule structural corrector drug candidates targeting the unique, neurotoxic conformation of mutant huntingtin

Funding Type: 
Early Translational IV
Grant Number: 
TR4-06847
Investigator: 
ICOC Funds Committed: 
$1 333 795
Disease Focus: 
Huntington's Disease
Neurological Disorders
Stem Cell Use: 
iPS Cell
oldStatus: 
Active
Public Abstract: 
The long-term objective of this project is to develop a drug to treat Huntington’s disease (HD), the most common inherited neurodegenerative disorder. Characterized by involuntary movements, personality changes and dementia, HD is a devastatingly progressive disease that results in death 10–20 years after disease onset and diagnosis. No therapy presently exists for HD; therefore, this project is highly innovative and ultimately aims to deliver something transformative for the HD patient population. The specific goal of the proposed research will be to achieve preclinical proof-of-concept with a novel small molecule that binds to and ameliorates the neurotoxicity of the mutant huntingtin (mHtt) protein that causes HD. Rationale for development of such compounds comes from previous research that found that mHtt assumes a shape that is selectively toxic to neurons, and that small molecules that disrupt this shape can reduce mHtt’s toxicity in primary neurons. Critical to the proposed studies will be assays that employ human striatal neurons derived from adult and juvenile HD patients and generated with induced pluripotent stem cell (iPSC) technology. These HD i-neurons display many characteristics that are also observed in striatal neurons of HD patients, including reduced survival times. They provide the most genetically precise preclinical system available to test for both drug efficacy and safety.
Statement of Benefit to California: 
The long-term objective of this project is to develop a first-in-class, disease-modifying drug to treat Huntington’s disease (HD), a devastatingly progressive genetic disorder that results in death 10–20 years after disease onset and diagnosis. No therapy presently exists for HD; therefore, this highly innovative project aims to deliver a medical breakthrough that will provide significant benefit for California’s estimated > 2000 HD patients and the family members, friends and medical system that care for them. The proposed research will be performed at a biotechnology startup, a leading academic research center and two contract research organizations, all of which are California-based. The work will over time involve more than 10 California scientists, thereby helping to employ tax-paying citizens and maintain the State’s advanced technical base. Finally, an effective, proprietary drug for the treatment of HD is expected to be highly valuable and to attract favorable financial terms upon out-licensing for development and commercialization. These revenues would flow to the California companies and institutions (including CIRM) that would have a stake in the proceeds.

A hESc-based Development Candidate for Huntington's Disease

Funding Type: 
Early Translational II
Grant Number: 
TR2-01841
ICOC Funds Committed: 
$3 799 817
Disease Focus: 
Huntington's Disease
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
Cell Line Generation: 
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 
Huntington’s disease (HD) is a devastating degenerative brain disease with a 1 in 10,000 prevalence that inevitably leads to death. These numbers do not fully reflect the large societal and familial cost of HD, which requires extensive caregiving. HD has no effective treatment or cure and symptoms unstoppably progress for 15-20 years, with onset typically striking in midlife. Because HD is genetically dominant, the disease has a 50% chance of being inherited by the children of patients. Symptoms of the disease include uncontrolled movements, difficulties in carrying out daily tasks or continuing employment, and severe psychiatric manifestations including depression. Current treatments only address some symptoms and do not change the course of the disease, therefore a completely unmet medical need exists. Human embryonic stem cells (hESCs) offer a possible long-term treatment approach that could relieve the tremendous suffering experienced by patients and their families. HD is the 3rd most prevalent neurodegenerative disease, but because it is entirely genetic and the mutation known, a diagnosis can be made with certainty and clinical applications of hESCs may provide insights into treating brain diseases that are not caused by a single, known mutation. Trials in mice where protective factors were directly delivered to the brains of HD mice have been effective, suggesting that delivery of these factors by hESCs may help patients. Transplantation of fetal brain tissue in HD patients suggests that replacing neurons that are lost may also be effective. The ability to differentiate hESCs into neuronal populations offers a powerful and sustainable alternative for cell replacement. Further, hESCs offer an opportunity to create cell models in which to identify earlier markers of disease onset and progression and for drug development. We have assembled a multidisciplinary team of investigators and consultants who will integrate basic and translational research with the goal of generating a lead developmental candidate having disease modifying activity with sufficient promise to initiate IND-enabling activities for HD clinical trials. The collaborative research team is comprised of investigators from multiple California institutions and has been assembled to maximize leverage of existing resources and expertise within the HD and stem cell fields.
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. As the disease progresses, individuals require institutional care 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. For the potential of hESCs in HD to be realized, a very forward-thinking team effort will allow highly experienced investigators in HD, stem cell research and clinical trials to come together and identify a lead development candidate for treatment of HD. This early translation grant will allow for a comprehensive and systematic evaluation of hESC-derived cell lines to identify a candidate and develop a candidate line into a viable treatment option. HD is the 3rd most prevalent neurodegenerative disease, but because it is entirely genetic and the mutation known, a diagnosis can be made with certainty and clinical applications of hESCs may provide insights into treating brain diseases that are not caused by a single, known mutation. We have assembled a strong team of California-based investigators to carry out the proposed studies. Anticipated benefits to the citizens of California include: 1) development of new human stem cell-based treatments for HD with application to other neurodegenerative diseases such as Alzheimer's and Parkinson's diseases that affect thousands of individuals in California; 2) improved methods for following the course of the disease in order to treat HD as early as possible before symptoms are manifest; 3) transfer of new technologies and intellectual property to the public realm with resulting IP revenues coming into the state with possible creation of new biotechnology spin-off companies; and 4) reductions in extensive care-giving and medical costs. It is anticipated that the return to the State in terms of revenue, health benefits for its Citizens and job creation will be significant.
Progress Report: 
  • Huntington’s disease (HD) is a devastating degenerative brain disease with a 1 in 10,000 prevalence that inevitably leads to death. Because HD is genetically dominant, the disease has a 50% chance of being inherited by the children of patients. Symptoms of the disease include uncontrolled movements, difficulties in carrying out daily tasks or continuing employment, and severe psychiatric manifestations including depression. Current treatments only address some symptoms and do not change the course of the disease, therefore a completely unmet medical need exists. Human embryonic stem cells (hESCs) offer a possible long-term treatment approach that could relieve the tremendous suffering experienced by patients and their families. Because HD is entirely genetic and the mutation known, a diagnosis can be made with certainty and clinical applications of hESCs may provide insights into treating brain diseases that are not caused by a single, known mutation. The ability to differentiate hESCs into neuronal populations offers a powerful and sustainable treatment opportunity. We have established the multidisciplinary team of investigators and consultants to integrate basic and translational research with the goal of generating a lead developmental candidate having disease modifying activity with sufficient promise to initiate IND-enabling activities for HD clinical trials.
  • In preliminary experiments, the transplantation of mouse neural stem cells, which survived in the brain for the four week period of the trial, provided protective effects in delaying disease progression in an HD mouse model and increased production of protective molecules in the brains of these mice. In the first year, the team has developed and established methods to differentiate hESCs into neural, neuronal and astrocyte precursors to be used for transplantation and has determined the correct cells to use that can be developed for future clinical development of these cells. In initial studies during this year, transplantation of neural stem cells (NSCs) provided both neurological and behavioral benefit to a HD mouse model. In addition, neuroprotective molecules were increased. Three immunosuppression regimens were tested to optimize methods for next stage preclinical trials. Finally, breeding of the three different HD mouse models has been initiated. Taken as a whole, progress supports the feasibility of the CIRM-funded studies to transplant differentiated hESCs into HD mice for preclinical development with the ultimate goal of initiating IND-enabling activities for HD clinical trials.
  • Huntington’s disease (HD) is a devastating degenerative brain disease with a 1 in 10,000 prevalence that inevitably leads to death. Because HD is genetically dominant, the disease has a 50% chance of being inherited by the children of patients. Symptoms of the disease include uncontrolled movements, difficulties in carrying out daily tasks or continuing employment, and severe psychiatric manifestations including depression. Current treatments only address some symptoms and do not change the course of the disease, therefore a completely unmet medical need exists. Human embryonic stem cells (hESCs) offer a possible long-term treatment approach that could relieve the tremendous suffering experienced by patients and their families. Because HD is entirely genetic and the mutation known, a diagnosis can be made with certainty and clinical applications of hESCs may provide insights into treating brain diseases that are not caused by a single, known mutation. The ability to differentiate hESCs into neuronal populations offers a powerful and sustainable treatment opportunity. We have established the multidisciplinary team of investigators and consultants to integrate basic and translational research with the goal of generating a lead developmental candidate having disease modifying activity with sufficient promise to initiate IND-enabling activities for HD clinical trials.
  • We previously performed transplantation of human neural stem cells into an HD mouse model and found that a subset of cells survived in the brain for the four week period of the trial, providing protective effects in delaying disease progression. In the past year, we have increased production and characterization of human neural stem cells (hNSCs) into neuronal (hNPC) and astrocyte (hAPC) precursors to be used for transplantation and optimized methods for shipping and implantation. Immunosuppression regimens were improved to optimize cell survival of implanted cells in HD mice. Transplantation of both human NSCs and NPCs are neuroprotective to HD mice and transplantation of hAPCs is in progress. Once completed, the cell giving the greatest protective benefit will be transplanted into mice that display slower progression over a longer time frame to validate and optimize approach for subsequent human application. All three HD mouse models have been bred and are ready for stem cell transplants. Taken as a whole, progress supports the feasibility of the CIRM-funded studies to transplant differentiated hESC-derived cell types into HD mice for preclinical development with the ultimate goal of identifying a lead candidate cell type and initiating IND-enabling activities for HD clinical trials.
  • Huntington’s disease (HD) is a devastating degenerative brain disease with a 1 in 10,000 prevalence that inevitably leads to death. Because HD is genetically dominant, the disease has a 50% chance of being inherited by the children of patients. Symptoms of the disease include uncontrolled movements, difficulties in carrying out daily tasks or continuing employment, and severe psychiatric manifestations including depression. Current treatments only address some symptoms and do not change the course of the disease, therefore a completely unmet medical need exists. Human embryonic stem cells (hESCs) offer a possible long-term treatment approach that could relieve the tremendous suffering experienced by patients and their families. Because HD is entirely genetic and the mutation known, a diagnosis can be made with certainty and clinical applications of hESCs may provide insights into treating brain diseases that are not caused by a single, known mutation. The ability to differentiate hESCs into neuronal populations offers a powerful and sustainable treatment opportunity. We have established the multidisciplinary team of investigators and consultants to integrate basic and translational research with the goal of generating a lead developmental candidate having disease modifying activity with sufficient promise to initiate Investigational New Drug (IND) enabling activities for HD clinical trials.
  • We have completed several rounds of transplantation of human neural stem cells into an HD mouse model and found that the cells survived in the brain for the four-week period of the trial, provided protective effects in delaying disease progression and increased production of protective molecules in the brains of these mice. In the last year the team differentiated hESCs into neural, neuronal and astrocyte precursors and performed transplantation studies to determine the best cell candidate to use and develop for future clinical work. We determined that the human neural stem cells produce the most robust effect. We have now selected a GMP grade hNSC line that will be carried forward for further testing in both rapidly progressing and slower progressing HD mice, as well as in mouse preclinical dosing studies. Taken as a whole, progress supports the feasibility of the CIRM-funded studies to transplant differentiated hESCs into HD mice for preclinical development with the ultimate goal on initiating IND-enabling activities for HD clinical trials.

MSC engineered to produce BDNF for the treatment of Huntington's disease

Funding Type: 
Disease Team Therapy Development - Research
Grant Number: 
DR2A-05415
ICOC Funds Committed: 
$18 950 061
Disease Focus: 
Huntington's Disease
Neurological Disorders
Stem Cell Use: 
Adult Stem Cell
Cell Line Generation: 
Adult Stem Cell
oldStatus: 
Active
Public Abstract: 
One in every ten thousand people in the USA has Huntington's disease, and it impacts many more. Multiple generations within a family can inherit the disease, resulting in escalating health care costs and draining family resources. This highly devastating and fatal disease touches all races and socioeconomic levels, and there are currently no cures. Screening for the mutant HD gene is available, but the at-risk children of an affected parent often do not wish to be tested since there are currently no early prevention strategies or effective treatments. We propose a novel therapy to treat HD; implantation of cells engineered to secrete Brain-Derived Neurotrophic factor (BDNF), a factor needed by neurons to remain alive and healthy, but which plummets to very low levels in HD patients due to interference by the mutant Huntingtin (htt) protein that is the hallmark of the disease. Intrastriatal implantation of mesenchymal stem cells (MSC) has significant neurorestorative effects and is safe in animal models. We have discovered that MSC are remarkably effective delivery vehicles, moving robustly through the tissue and infusing therapeutic molecules into each damaged cell that they contact. Thus we are utilizing nature's own paramedic system, but we are arming them with enhanced neurotrophic factor secretion to enhance the health of at-risk neurons. Our novel animal models will allow the therapy to be carefully tested in preparation for a phase I clinical trial of MSC/BDNF infusion into the brain tissue of HD patients, with the goal of restoring the health of neurons that have been damaged by the mutant htt protein. Delivery of BDNF by MSC into the brains of HD mice is safe and has resulted in a significant reduction in their behavioral deficits, nearly back to normal levels. We are doing further work to ensure that the proposed therapy will be safe and effective, in preparation for the phase I clinical trial. The significance of our studies is very high because there are currently no treatments to diminish the unrelenting decline in the numbers of medium spiny neurons in the striata of patients affected by HD. Our biological delivery system for BDNF could also be modified for other neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS), spinocerebellar ataxia (SCA1), Alzheimer's Disease, and some forms of Parkinson's Disease, where neuroregeneration is needed. Development of novel stem cell therapies is extremely important for the community of HD and neurodegenerative disease researchers, patients, and families. Since HD patients unfortunately have few other options, the potential benefit to risk ratio for the planned trial is very high.
Statement of Benefit to California: 
It is estimated that one in 10,000 CA residents have Huntington’s disease (HD). While the financial burden of HD is estimated to be in the billions, the emotional cost to friends, families, and those with or at risk for HD is immeasurable. Health care costs are extremely high for HD patients due to the long progression of the disease, often for two decades. The lost ability of HD patients to remain in the CA workforce, to support their families, and to pay taxes causes additional financial strain on the state’s economy. HD is inherited as an autosomal dominant trait, which means that 50% of the children of an HD patient will inherit the disease and will in turn pass it on to 50% of their children. Individuals diagnosed through genetic testing are at risk of losing insurance coverage in spite of reforms, and can be discriminated against for jobs, school, loans, or other applications. Since there are currently no cures or successful clinical trials to treat HD, many who are at risk are very reluctant to be tested. We are designing trials to treat HD through rescuing neurons in the earlier phases of the disease, before lives are devastated. Mesenchymal stem cells (MSC) have been shown to have significant effects on restoring synaptic connections between damaged neurons, promoting neurite outgrowth, secreting anti-apoptotic factors in the brain, and regulating inflammation. In addition to many trials that have assessed the safety and efficacy of human MSC delivery to tissues via systemic IV infusion, MSC are also under consideration for treatment of disorders in the CNS, although few MSC clinical trials have started so far with direct delivery to brain or spinal cord tissue. Therefore we are conducting detailed studies in support of clinical trials that will feature MSC implantation into the brain, to deliver the neurotrophic factor BDNF that is lacking in HD. MSC can be transferred from one donor to the next without tissue matching because they shelter themselves from the immune system. We have demonstrated the safe and effective production of engineered molecules from human MSC for at least 18 months, in pre-clinical animal studies, and have shown with our collaborators that delivery of BDNF can have significant effects on reducing disease progression in HD rodent models. We are developing a therapeutic strategy to treat HD, since the need is so acute. HD patient advocates are admirably among the most vocal in California about their desire for CIRM-funded cures, attending almost every public meeting of the governing board of the California Institute for Regenerative Medicine (CIRM). We are working carefully and intensely toward the planned FDA-approved approved cellular therapy for HD patients, which could have a major impact on those affected in California. In addition, the methods, preclinical testing models, and clinical trial design that we are developing could have far-reaching impact on the treatment of other neurodegenerative disorders.
Progress Report: 
  • Huntington’s disease (HD) is a hereditary, fatal neuropsychiatric disease. HD occurs in one in every ten thousand people in the USA. The effects of the disease on patients, families, and care givers are devastating as it reaches from generation to generation. This fatal disease touches all races and socioeconomic levels, and current treatment is strictly palliative. Existing drugs can reduce the involuntary movements and psychiatric symptoms, but do nothing to slow the inexorable progression. There is currently no cure for HD. People at risk of inheriting HD can undergo a genetic counseling and testing to learn if they are destined to develop this dreadful disease. Many people from HD families fear the consequences of stigma and genetic discrimination. Those at-risk often do not choose to be tested since there are currently no early prevention strategies or effective treatments.
  • We propose a novel therapy to treat HD: implantation of cells engineered to secrete Brain-Derived
  • Neurotrophic Factor (BDNF), a factor that can promote addition of new neurons to the affected area of the brain. BDNF is reduced in HD patients due to interference by the mutant Huntingtin (htt) protein that is the hallmark of the disease. We have discovered that mesenchymal stem/stromal cells (MSC), a type of adult stem cell, are remarkably effective delivery vehicles, moving robustly through the tissue and infusing therapeutic molecules into damaged cells they contact. In animal models of HD implantation of MSC into the brain has significant neurorestorative effects and is safe. We propose to use these MSCs as “nature's own paramedic system”, arming them with BDNF to enhance the health of at-risk neurons. Our HD animal models will allow the therapy to be carefully tested in preparation for a proposed Phase I clinical trial of MSC/BDNF implantation into the brain of HD patients (HD-CELL), with the goal of slowing disease progression.
  • Delivery of BDNF by MSC into the brains of HD mice is safe and has resulted in a significant reduction in their behavioral deficits, nearly back to normal levels. We are doing further efficacy and safety studies in preparation for the Phase I clinical trial. The significance of our studies is very high because there are currently no other options, there is no current treatment to delay the onset or slow the progression of the disease.. There are potential applications beyond Huntington’s disease. Our biological delivery system for BDNF sets the precedent for adult stem cell therapy in the brain and could potentially be modified for other neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS), spinocerebellar ataxia (SCA), Alzheimer's disease, and some forms of Parkinson's disease. Since HD patients unfortunately have few other options, the potential benefit to risk ratio for the planned trial is very high.
  • In the first year of our grant we have successfully engineered human MSCs to produce BDNF, and are studying effects on disease progression in HD mice. We have developed methods to produce these cells in large quantities to be used for future human clinical studies. As we go forward in year 2 we plan to complete the animal studies that will allow us to apply for regulatory approval to go forward with the planned Phase I trial.
  • We have designed an observational study, PRE-CELL, to track disease progression and generate useful data in preparation for this future planned Phase I clinical trial. PRE-CELL has been approved by the institution’s ethics board and is currently enrolling subjects. PRE-CELL was designed to operate concurrently with the ongoing pre-clinical safety testing. For additional information go to: ClinicalTrials.gov Identifier: NCT01937923

Common molecular mechanisms in neurodegenerative diseases using patient based iPSC neurons

Funding Type: 
Basic Biology IV
Grant Number: 
RB4-06079
ICOC Funds Committed: 
$1 506 420
Disease Focus: 
Huntington's Disease
Neurological Disorders
Parkinson's Disease
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Active
Public Abstract: 
A major medical problem in CA is the growing population of individuals with neurodegenerative diseases, including Parkinson’s (PD) and Huntington’s (HD) disease. These diseases affect millions of people, sometimes during the prime of their lives, and lead to total incapacitation and ultimately death. No treatment blocks the progression of neurodegeneration. We propose to conduct fundamental studies to understand the basic common disease mechanisms of neurodegenerative disorders to begin to develop effective treatments for these diseases. Our work will target human stem cells made from cells from patients with HD and PD that are developed into the very cells that degenerate in these diseases, striatal neurons and dopamine neurons, respectively. We will use a highly integrated approach with innovative molecular analysis of gene networks that change the states of proteins in these diseases and state-of-the-art imaging technology to visualize living neurons in a culture dish to assess cause and effect relationships between biochemical changes in the cells and their gradual death. Importantly, we will test whether drugs effective in animal model systems are also effective in blocking the disease mechanisms in the human HD and PD neurons. These human preclinical studies could rapidly lead to clinical testing, since some of the drugs have already been examined extensively in humans in the past for treating other disorders and are safe.
Statement of Benefit to California: 
Neurodegenerative diseases, such as Parkinson’s (PD) and Huntington’s disease (HD), are devastating to patients and families and place a major financial burden on California. No treatments effectively block progression of any neurodegenerative disease. A forward-thinking team effort will allow highly experienced investigators in neurodegenerative disease and stem cell research to investigate common basic mechanisms that cause these diseases. Most important is the translational impact of our studies. We will use neurons and astrocytes derived from patient induced pluripotent stem cells to identify novel targets and discover disease-modifying drugs to block the degenerative process. These can be quickly transitioned to testing in preclinical and clinical trials to treat HD and other neurodegenerative diseases. We are building on an existing strong team of California-based investigators to complete the studies. Future benefits to California citizens include: 1) discovery and development of new HD treatments with application to other diseases, such as PD, that affect thousands of Californians, 2) transfer of new technologies and intellectual property to the public realm with resulting IP revenues to the state with possible creation of new biotechnology spin-off companies, and 3) reductions in extensive care-giving and medical costs. We anticipate the return to the State in terms of revenue, health benefits for its Citizens and job creation will be significant.
Progress Report: 
  • The goal of our study is to identify common mechanisms that cause the degeneration of neurons and lead to most neurodegenerative disorders. Our work focuses on the protein homeostasis pathways that are disrupted in many forms of neurodegeneration, including Huntington’s disease (HD) and Parkinson’s disease (PD). In this first reporting period we have made great progress in developing novel methods to probe the autophagy pathway in single cells. This pathway is involved in the turnover of misfolded proteins and dysfunction organelles. Using our novel autophagy assays, we have preliminary data that indicate that the autophagy pathway in neurons from HD patients is modulated compared to healthy controls. We have also begun validating small molecules that activate the autophagy pathway and we are now moving these inducers into human neurons from HD patients to see if they reduce toxicity or other disease related phenotypes. Using pathway analysis we have also identified specific genes within the proteostasis network that are modulated in HD. We are now testing whether modulating these genes in human neurons from HD patients can lead to a reduction in neurodegeneration. In the final part of this study we are investigating whether neurodegenerative diseases, such as HD and PD, share changes in similar genes or pathways, specifically those involved in protein homeostasis. We have now established a human neuron model for PD and have used it to identify potential targets that modulate the disease phenotype via changes in proteostasis. Using the assays, autophagy drugs and pathway analysis described above, we hope to identify overlapping targets that could potentially rescue disease associated phenotypes in both HD and PD.

The HD iPSC Consortium: Repeat Length Dependent Phenotypes for Assay Development

Funding Type: 
iPSC Consortia Award
Grant Number: 
RP1-05741
ICOC Funds Committed: 
$300 000
Disease Focus: 
Huntington's Disease
Neurological Disorders
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Active
Public Abstract: 
Statement of Benefit to California: 
Progress Report: 
  • Huntington’s disease (HD) is a significant neurodegenerative disease with unique genetic features. A CAG expansion in Huntington gene is correlated with severity and onset of sub-clinical and overt clinical symptoms, make it particularly suited to therapeutic development . The single genetic cause offers the opportunity to understand the pathological process triggered in all individuals with a CAG expansion, as emerging evidence suggests effects of the mutation in all cell types, though striatal neurons are most vulnerable to degeneration. Moreover, by virtue of a molecular test for the mutation, a unique opportunity exists to intervene/treat before the onset of overt clinical symptoms utilizing sub-clinical phenotypes emerging in pre-manifest individuals. Since human induced pluripotent stem cells (iPSCs) have the power to make any cell type in the human body, we are utilizing the technology to make patients iPSCs and study the effects of different number of CAG repeats on the neurons we generate from the patient iPS cells. Preliminary studies indicate that CAG length–dependent phenotypes occur at all stages of differentiation, from iPSC through to mature neurons and are likely to occur in non-neuronal cells as well, which can also be investigated using the iPSC that we are creating. The non-integrating technology (avoids integration of potentially deleterious reprogramming factors in the cell DNA) for producing iPSC lines is crucial to obtaining reproducible disease traits from patient cells.
  • The Cedars-Sinai RMI iPSC Core is part of the Huntington’s Disease (HD) consortium. In the past year the iPSC Core has made many new non-integrating induced pluripotent stem (iPSC) cell lines from HD patients with different numbers of CAG repeat expansions. The grant application proposed generation of 18 HD and Control iPSC lines. Instead we are generating 20 iPSC lines. So far we have already generated 17 iPSC lines from individuals with Huntington’s disease and controls (10 HD patients and 7 controls). In order to have the disease trait reproducible across multiple groups, three clonal iPSC lines were generated from each subject. Some of these lines have (or are in process) of expansion for distribution to consortium members. We are now in the process of making the last 3 lines as part of this grant application to generate a HD iPSC repository with total of 20 patient/control lines from subjects with multitude of CAG repeat numbers. Most of these lines have undergone rigorous battery of characterization for pluripotency determination, while some other lines are currently being validated through more characterization tests. Neural stem cell aggregates (EZ spheres) have been generated from few of the patient lines in the Svendsen lab (not supported by this grant). We have also submitted 6 patient iPSC lines to Coriell Cell Repository for larger banking and distribution of these important and resourceful lines to other academic investigators and industry. We strongly believe that this iPSC repository will enormously speed up the process of understanding the disease causing mechanisms in HD patient brain cells as well as discovering novel therapeutics or drugs that may one day be able to treat HD patients.

MSC engineered to produce BDNF for the treatment of Huntington's disease

Funding Type: 
Disease Team Therapy Planning I
Grant Number: 
DR2-05415
ICOC Funds Committed: 
$99 248
Disease Focus: 
Huntington's Disease
Neurological Disorders
oldStatus: 
Closed
Public Abstract: 
One in every ten thousand people in the USA has Huntington's disease, and it impacts many more. Multiple generations within a family can inherit the disease, resulting in escalating health care costs and draining family resources. This highly devastating and fatal disease touches all races and socioeconomic levels, and there are currently no cures. Screening for the mutant HD gene is available, but the at-risk children of an affected parent often do not wish to be tested since there are currently no early prevention strategies or effective treatments. We propose a novel therapy to treat HD; implantation of cells engineered to secrete Brain-Derived Neurotrophic factor (BDNF), a factor needed by neurons to remain alive and healthy, but which plummets to very low levels in HD patients due to interference by the mutant Huntingtin (htt) protein that is the hallmark of the disease. Intrastriatal implantation of mesenchymal stem cells (MSC) has significant neurorestorative effects and is safe in animal models. We have discovered that MSC are remarkably effective delivery vehicles, moving robustly through the tissue and infusing therapeutic molecules into each damaged cell that they contact. Thus we are utilizing nature's own paramedic system, but we are arming them with enhanced neurotrophic factor secretion to enhance the health of at-risk neurons. Our novel animal models will allow the therapy to be carefully tested in preparation for a phase 1 clinical trial of MSC/BDNF infusion into the brain tissue of HD patients, with the goal of restoring the health of neurons that have been damaged by the mutant htt protein. Delivery of BDNF by MSC into the brains of HD mice is safe and has resulted in a significant reduction in their behavioral deficits, nearly back to normal levels. We are doing further work to ensure that the proposed therapy will be safe and effective, in preparation for the phase 1 clinical trial. The significance of our studies is very high because there are currently no treatments to diminish the unrelenting decline in the numbers of medium spiny neurons in the striata of patients affected by HD. However this biological delivery system for BDNF could also be modified for other neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS), spinocerebellar ataxia (SCA1), Alzheimer's Disease, and some forms of Parkinson's Disease, where neuroregeneration is needed. Development of novel stem cell therapies is extremely important for the community of HD and neurodegenerative disease researchers, patients, and families. Since HD patients unfortunately have few other options, the benefit to risk ratio for the planned trial is very high.
Statement of Benefit to California: 
It is estimated that one in 10,000 CA residents have Huntington’s disease (HD). While the financial burden of HD is estimated to be in the billions, the emotional cost to friends, families, and those with or at risk for HD is immeasurable. Health care costs are extremely high for HD patients due to the long progression of the disease, often for two decades. The lost ability of HD patients to remain in the CA workforce, to support their families, and to pay taxes causes additional financial strain on the state’s economy. HD is inherited as an autosomal dominant trait, which means that 50% of the children of an HD patient will inherit the disease and will in turn pass it on to 50% of their children. Individuals diagnosed through genetic testing are at risk of losing insurance coverage in spite of reforms, and can be discriminated against for jobs, school, loans, or other applications. Since there are currently no cures or successful clinical trials to treat HD, many who are at risk are very reluctant to be tested. We are designing trials to treat HD through rescuing neurons in the earlier phases of the disease, before lives are devastated. Mesenchymal stem cells (MSC) have been shown to have significant effects on restoring synaptic connections between damaged neurons, promoting neurite outgrowth, secreting anti-apoptotic factors in the brain, and regulating inflammation. In addition to many trials that have assessed the safety and efficacy of human MSC delivery to tissues via systemic IV infusion, MSC are also under consideration for treatment of disorders in the CNS, although few MSC clinical trials have started so far with direct delivery to brain or spinal cord tissue. Therefore we are conducting detailed studies in support of clinical trials that will feature MSC implantation into the brain, to deliver the neurotrophic factor BDNF that is lacking in HD. MSC can be transferred from one donor to the next without tissue matching because they shelter themselves from the immune system. We have demonstrated the safe and effective production of engineered molecules from human MSC for at least 18 months, in pre-clinical animal studies, and have shown with our collaborators that delivery of BDNF can have significant effects on reducing disease progression in HD rodent models. We are developing a therapeutic strategy to treat HD, since the need is so acute. HD patient advocates are admirably among the most vocal in California about their desire for CIRM-funded cures, attending almost every public meeting of the governing board of the California Institute for Regenerative Medicine (CIRM). We are working carefully and intensely toward the first FDA-approved approved cellular therapy for HD patients which could have a major impact on those affected in California. In addition, the methods, preclinical testing models, and clincial trial design that we are developing could have far-reaching impact on the treatment of other neurodegenerative disorders.
Progress Report: 
  • A) Pre-clinical: The remainder of the IND-enabling studies were designed in consultation with Biologics Consulting Group (BCG). The project will begin with the IND-enabling phase and transition through regulatory approvals and through an observational trial and the Phase I clinical trial of stem cell therapy. The project has a Preclinical unit, under the leadership of co-PI Dr. Jan Nolta, and a Clinical unit, under the leadership of PI Dr. Vicki Wheelock. The two units are well integrated, since the team has been meeting weekly since 2009 to plan the testing of MSC trials for HD. During the planning phase we had a minimum of 4 hours of HD meetings per week, and worked continually on the project. This team is truly translational, with both PIs highly dedicated to this trial and motivated by the HD community.
  • Co-PI Jan Nolta, Ph.D. is Scientific Director of the UC Davis/CIRM GMP Facility, and will continue to direct ongoing IND-enabling studies for MSC/BDNF. The Pre-Clinical team will perform all IND-enabling studies at the level of GLP, and will manufacture and qualify the MSC and MSC/BDNF products in the GMP facility at UC Davis that is directed by Dr. Bauer (CMC lead). These studies are ongoing and we have been advised by BCG consulting lead Andra Miller, who was formerly Gene Therapy Group Leader at the FDA, CBER, Division of Cell and Gene Therapies, for almost a decade. BCG is assisting us with IND preparation.
  • Ms. Geralyn Annett is the experienced Project Manager. She is the UCD Stem Cell Program Manager and has worked in the field of academic and industry stem cell trials for 20+ years. She will oversee the regulatory team and keep the IND-enabling studies on task to meet the milestones. GMP Facility Director Gerhard Bauer will be responsible for regulatory filings with assistance from Dr. Nolta, the CMC team, and Dr. Miller. Dr. Nolta has worked on clinical trials of stem cell gene therapy, and associated translational studies with Ms. Annett and Director Bauer for over 20 years.
  • B) Clinical. The Clinical team is led by PI Dr. Vicki Wheelock, who is Director of the HDSA Center of Excellence at UC Davis and, with nurse practitioner Terry Tempkin, follows over 250 patients with HD in the UC Davis Movement Disorders clinic. The PI has extensive experience in conducting clinical trials and has already accrued HD patients to 14 clinical trials to date. The planning grant allowed us to conduct longer weekly meetings with different team members to complete planning of the proposed clinical trial.
  • Weekly HD meetings during the planning phase included PI Dr. Wheelock, Co-PI Dr. Nolta, Nurse practitioner Terry Tempkin, Program Manager Geralyn Annett, Psychiatrist Dr. Lorin Scher, Neuropsychologist Dr. Sarah Farias, Social Worker Lisa Kjer, and members of the Imaging Unit led by Dr. Charles DeCarli. This team has worked together on multiple clinical trials for HD patients. Some meetings additionally included Dr. Kiarash Shahlaie, the UCD functional neurosurgeon who will perform the targeting and surgical implantation of the cells, Dr. Bauer who directs the GMP facility (and his team members), the translational team who is performing the IND-enabling studies in Rodents (they usually meet separately for 2 hours/week with Dr. Nolta), and Dr. Tarantal who is leading the IND-enabling studies in non-human primates.
  • We met with our CRO, Paragon, who will be responsible for regulatory and safety filings including outcomes reports, medical and safety monitoring and management including DSMB, medical writing and quality assurance, clinical events committee- adjudicate AEs, and generate clinical study reports. Paragon will also oversee the development of the electronic case report forms, site management and monitoring, biostatistical analysis, and management of the database. We had on-site meetings and conference calls with Paragon during the planning Phase.
  • Additional meetings were conducted with collaborators and consultants:
  • A) Dunbar lab and Hersch lab in the US, both leaders in the HD field – for HD trial IND-enabling study research and HD mouse and patient biomarkers, respectively.
  • B) Aylward lab in the US for detailed brain imaging analyses in HD.
  • C) Paulsen lab for interpretation of cognitive assays in HD.
  • D) Phil Starr and Dan Lim at UCSF for ClearPoint cell injection system.
  • E) Bachoud-Levi lab in France for cell implantation in HD.
  • F) Dr. Robert (Willie) Mays and Bob Deans, Athersys – for IND-enabling studies/regulatory
  • In conclusion, the planning grant helped us to finalize plans for the proposed clinical trial and to complete our detailed plans for the remainder of the IND-enabling studies required to obtain FDA approval. These goals were accomplished through frequent meetings with key consultants and collaborators during the intense planning phase, where we completed the Disease Team application to CIRM that could potentially fund our proposed Phase I clinical trial of MSC/BDNF therapy for Huntington’s disease.

Triplet Repeat Instability in Human iPSCs

Funding Type: 
Basic Biology III
Grant Number: 
RB3-05022
ICOC Funds Committed: 
$1 755 861
Disease Focus: 
Huntington's Disease
Neurological Disorders
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Active
Public Abstract: 
Over twenty human genetic diseases are caused by expansion of simple DNA sequences composed of repeats of three nucleotides (such as CAG, CTG, CGG and GAA) within essential genes. These repeats can occur within the region of a gene that encodes the protein, generally resulting in proteins with large stretches of repeats of just one amino acid, such as runs of glutamine. These proteins are toxic, cause the death of specific types of brain cells and result in diseases such as Huntington’s disease (HD) and many of the spinocerebellar ataxias (a type of movement disorder). Other repeats can be in regions of genes that do not code for the protein itself, but are copied into messenger RNA, which is a copy of the gene that serves to generate the protein. These RNAs with expanded repeats are also toxic to cells, and sometimes these RNAs sequester essential cellular proteins. One example of this type of disease is Myotonic Dystrophy type 1, a form of muscular dystrophy. Lastly, there are two examples of repeat disorders where the repeats silence the genes harboring these mutations: these are Friedreich’s ataxia (FRDA) and Fragile X syndrome (FXS). One limitation in the development of drugs to treat these diseases is the lack of appropriate cell models that represent the types of cells that are affected in these human diseases. With the advent of the technology to produce induced pluripotent stem cells from patient skin cells, and our ability to turn iPSCs into any cell type, such as neurons (brain cells) that are affected in these triplet repeat diseases, such cellular models are now becoming available. Our laboratories have generated iPSCs from fibroblasts obtained from patients with HD, FXS and FRDA. By comparing cells before and after reprogramming, we found that triplet repeats were expanded in the FRDA iPSCs, but not in HD iPSCs. This application is aimed at the understanding the molecular basis underlying triplet repeat expansion/instability that we have observed during the establishment and propagation of iPSCs from disease-specific fibroblasts. While artificial systems with reporter gene constructs have reproduced triplet repeat expansion in bacteria, yeast and mammalian cells, no cellular models have previously been reported that recapitulate repeat expansions at the endogenous cellular genes involved in these diseases. Therefore, our observations that repeat expansion is found in FRDA iPSCs provides the first opportunity to dissect the mechanisms involved in expansion at the molecular level for the authentic cellular genes in their natural chromatin environment. Repeat expansion is the central basis for these diseases, no matter what the outcome of the expansion (toxic protein or RNA or gene silencing), and a fuller understanding of how repeats expand may lead to new drugs to treat these diseases.
Statement of Benefit to California: 
A major obstacle in the development of new drugs for human diseases is our lack of cell models that represent the tissues or organs that are affected in these diseases. Examples of such diseases are the triplet-repeat neurodegenerative diseases, such as Huntington’s disease, the spinocerebellar ataxias, forms of muscular dystrophy, Fragile X syndrome and Friederich’s ataxia. These diseases, although relatively rare compared to cancer or heart disease, affect thousands of individuals in California. Recent advances in stem cell biology now make it possible to generate cells that reflect the cell types at risk in these diseases (such as brain, heart and muscle cells), starting from patient skin cells. Skin cells can be turned into stem cell-like cells (induced pluripotent stem cells or iPSCs), which can then give rise to just about any cell type in the human body. During the course of our studies, we found that iPSCs derived from Friedreich’s ataxia patient skin cells mimic the behavior of the genetic mutation in this disease. A simple repeat of the DNA sequence GAA is found in the gene encoding an essential protein called frataxin, and this repeat increases in length between generations in human families carrying this mutation. Over a certain threshold, the repeats silence this gene. It is also known that the repeats expand in brain cells in individuals with this disease. With the advent of patient derived iPSCs and neurons, we now have human model systems in which to study the mechanisms responsible for repeat expansion. We have already identified one set of proteins involved in repeat expansion and we now wish to delve more deeply into how the repeats expand. In this way, we may be able to identify new targets for drug development. We will extend our studies to Huntington’s disease and Fragile X syndrome. We have identified two possible therapeutic approaches for Friedreich’s ataxia, and identified molecules that either reactivate the silent gene or block repeat expansion. Our studies in related diseases may provide possible therapeutic strategies for these other disorders as well, which will be of benefit to patients suffering from these diseases, both in California and world-wide.
Progress Report: 
  • Over twenty human genetic diseases are caused by expansion of simple trinucleotide repeat sequences within essential genes, resulting in toxic proteins (as in the polyglutamine expansion diseases, such as Huntington’s disease (HD)), toxic RNAs (as in Myotonic Dystrophy type 1), or gene repression (as in Friedreich’s ataxia (FRDA) and Fragile X syndrome (FXS)). Our laboratories have generated induced pluripotent stem cells (iPSCs) from fibroblasts obtained from patients with Huntington’s disease (HD), Fragile X syndrome (FXS), Myotonic dystrophy type 1 (DM1) and Friedreich’s ataxia (FRDA). By comparing cells before and after reprogramming, we found that triplet repeats were expanded in the FRDA and DM1 iPSCs, but not in HD iPSCs. During growth of the iPSCs in culture, the repeats continue to expand, suggesting that expansion might be linked to DNA replication in these cells. The expansion we observe in iPSCs does not occur in the fibroblast (skin cells) from which the iPSCs were derived. Similarly, on differentiation of the FRDA iPSCs into neurons (brain cells), repeat expansion stops. This observation suggests that some cellular factors necessary for expansion may be selectively expressed in iPSCs, but not in fibroblasts or neurons.
  • Over the past year, our studies have been aimed at the understanding the molecular basis underlying triplet repeat expansion/instability that we have observed during the establishment and propagation of iPSCs from disease-specific fibroblasts. Previous studies have implicated the mismatch repair (MMR) enzymes in repeat expansion in mouse models for HD and DM1. We find that silencing of the MSH2 gene, encoding one of the subunits of the MMR enzymes, impedes repeat expansion in human FRDA iPSCs. We find that components of the human mismatch repair (MMR) system are associated with the disease alleles in the FRDA and DM1 iPSCs, and that silencing of these genes at the level of their messenger RNAs is sufficient to suppress repeat expansion. Moreover, we have monitored the levels of the MMR enzymes in fibroblasts, iPSCs and neurons, and as expected these enzymes are present at higher amounts in the iPSCs, suggesting that it is the availability of these enzymes in iPSCs that may be responsible for repeat expansion.
  • We wish to determine whether it is the DNA structure of triplet-repeats or protein recognition of the repeats that recruits the MMR enzymes to triplet repeats in iPSCs. To this end, we used a series of small molecule probes that can be designed to target particular DNA sequences in the human genome, and we find that a molecule that targets the GAA-TTC repeats in the FRDA frataxin gene displaces MMR enzymes and prevents repeat expansion. We are currently exploring the mechanism whereby this molecule displaces the MMR enzymes. A deeper understanding of the molecular events that lead to repeat expansion at the endogenous cellular genes responsible for these diseases will likely lead to discoveries of new therapeutic strategies for these currently untreatable disorders.
  • Over the past year, our research efforts have focused on the generality of the results we found in human induced pluripotent stem cells derived from patients with the neurodegenerative disease Friedreich's ataxia (FRDA). FRDA is one of the trinucleotide repeat (TNR) diseases, and our major previous finding was that the GAA•TCC trinucleotide repeats that cause FRDA expand during isolation and propagation of FRDA hiPSCs. This expansion was shown to be dependent on enzymes that are involved in the repair of mismatches in the human genome. To extend these studies, we have now focused on hiPSCs from the related TNR diseases myotonic dystrophy, Huntington's disease and Fragile X syndrome. Myotonic dystrophy type 1 (DM1) is an inherited dominant muscular dystrophy caused by expanded CTG•CAG triplet repeats in the 3’ UTR of the DMPK1 gene, which produces a toxic gain-of-function CUG RNA. It has been shown that the severity of disease symptoms, age of onset and progression are related to the length of the triplet repeats. However, the mechanism(s) of CTG•CAG triplet-repeat instability is not fully understood. Human induced pluripotent stem cells (iPSCs) were generated from DM1 and Huntington’s disease (HD) patient fibroblasts. We isolated 41 iPSC clones from DM1 fibroblasts, all showing different CTG•CAG repeat lengths, thus demonstrating somatic instability within the initial fibroblast population. During propagation of the iPSCs, the repeats expanded in a manner analogous to the intergenerational expansion observed in DM1 patient families. The correlation between repeat length and expansion rate identified the interval between 57 and 126 repeats as being an important length threshold where expansion rates dramatically increased. Moreover, longer repeats showed faster triplet-repeat expansion. The relatively short repeats in the gene responsible for Huntington's disease are below this threshold and hence do not expand in the iPSCs. The overall tendency of triplet repeats to expand ceased on differentiation into differentiated embryoid body or neurospheres. The mismatch repair components MSH2, MSH3 and MSH6 were highly expressed in iPSCs compared to fibroblasts, and only occupied the DMPK1 gene harboring longer CTG•CAG triplet repeats. In addition, shRNA silencing of MSH2 impeded CTG•CAG triplet-repeat expansion. We have also generated hiPSC lines from seven male subjects clinically diagnosed with fragile X syndrome. These hiPSCs have been thoroughly characterized with respect to pluripotency, DNA methylation status at the FMR1 gene, CGG repeat length, FMR1 expression and neuronal differentiation. The information gained from these studies provides new insight into a general mechanism of triplet repeat expansion in iPSCs.

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

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

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