Alzheimer’s disease (AD) is now a nation-wide epidemic and California is at the epicenter of the epidemic. One-tenth of all people in the United States diagnosed with AD live in California. In the US, 5.4 million people have AD and another American develops AD every 69 seconds. No therapeutic strategies exist to prevent or treat AD. And the situation is worse than expected. Results of a recent two year clinical study show that the currently available medications for managing AD symptoms are ineffective in patients with mild cognitive impairment or mild AD.
We seek to develop a small molecule therapeutic, allopregnanolone (APα) to prevent and treat AD. APα promotes the ability of brain to regenerate itself by increasing the number and survival of newly generated neurons. The APα-induced increase in newly generated neurons was associated with a reversal of cognitive deficits and restored learning and memory function to normal in a preclinical mouse model of AD. Further, APα reduced the amount of AD pathology in the brain. Importantly, when given peripherally either by injection under the skin or applied topically to the skin, APα was able to enter the brain to increase the generation of new neurons. The unique mechanism of APα action reduces the risk that APα would cause proliferation of other cells in the body. Because APα was efficacious in both pre-pathology and post-pathology stages of AD progression, APα has the potential to be effective for both the prevention of and early stage treatment of Alzheimer’s disease. Further, APα induced neurogenesis and restoration of cognitive function in normal aged mice suggesting that APα could be efficacious to sustain cognitive function and prevent development of AD in a normal aged population. In other clinical studies, APα has been proven safe in animals and humans and in both men and women. Together, these findings provide a strong foundation on which to plan a clinical trial of APα in persons with prodromal and diagnosed Alzheimer’s disease.
To plan for a Phase I-IIa clinical trial to determine safety, dosing and clinical efficacy, we have assembled an interdisciplinary team of clinicians, scientists, therapeutic development, regulatory, data management and statistical analysis experts. The objectives of this proposal are to: a) develop allopregnanolone as a therapeutic for Alzheimer’s disease; to plan an early clinical development program for its use as a neurogenesis agent; b) file a complete and well-supported IND with the Food and Drug Administration (FDA); c) complete phase I/IIa clinical studies to evaluate safety, biological activity, and early efficacy in humans; and (d) complete a phase II clinical trial that will evaluate efficacy and lead to larger multisite clinical studies of efficacy.
California is at the epicenter of the epidemic of Alzheimer’s disease (AD). Nationwide there are 5.4 million persons living with AD. Ten percent or over half a million Californians have AD. Among California’s baby boomers aged 55 and over, one in eight will develop AD. It is estimated that one in six Californians will develop a form of dementia. By 2030 the number of Californians living with AD will double to over 1.1 million. While all races and ethnic groups and regions of the state will be affected, not all regions within California will be equally affected. Los Angeles County has the greatest population in the state and thus will be the true epicenter of the Alzheimer’s epidemic in California.
Alzheimer’s is a disease that affects an entire family, community and health care system. Nation-wide there are nearly 15 million Alzheimer and dementia care givers providing 17 billion hours of unpaid care per year. Total costs for caring for people with AD, totals $183 billion per year. California shouldered $18.3 billion of those costs and most of those costs were born by persons and health care services in Los Angeles County. Because of the psychological and physical toll of caring for people with Alzheimer’s, caregivers had $7.9 billion in additional health care costs. Proportionally that translates into $790 million of health care costs for Californians. In total, California spent over $19 billion per year for costs associated with Alzheimer’s disease. Multiple analyses indicate that a delay of just 5 years can reduce the number of persons diagnosed with Alzheimer’s by 50% and dramatically reduce the associated costs.
We seek to develop a small molecule therapeutic, allopregnanolone (APα) to prevent and treat AD. APα promotes the innate regenerative capacity of the brain to increase the pool of neural progenitor cells. The APα-induced increase in neurogenesis was associated with a reversal of cognitive deficits and restored learning and memory function to normal in a preclinical mouse model of AD. Further, APα reduced the development of AD pathology. APα crosses the blood brain barrier and acts through a mechanism unique to neural progenitor cells and thus is unlikely to exert proliferative effects in other organs. Because APα was efficacious in both pre-pathology and post-pathology stages of AD progression, APα has the potential to be effective for both the prevention of and early stage treatment .
- As a result of the planning grant award, the Allopregnanolone (APα) team accomplished the following that enabled submission of the CIRM Disease Team Therapy Development Research Awards Proposal:
- 1) Created a team of experts in regeneration, neurology and Alzheimer's disease drug development to generate strategy and overall development plan. Through the team’s efforts we developed preclinical and clinical studies, determined correct dosing parameters for clinical studies, identified an optimal route of administration, developed chemistry, manufacturing and controls, and submitted our Pre-IND documents to the FDA.
- 2) Filed a Pre-IND document with the FDA and held a Pre-IND meeting with the FDA and obtained feedback from the FDA on our program. FDA provided guidance on requirements for the preclinical plan along with input on the design of our two Phase 2 clinical studies. We also obtained agreement that we may cross-reference the existing IND of our academic partner, Michael Rogawski at UC Davis and utilize product manufactured at UC Davis.
- 3) We developed an integrated CMC plan to manufacture allopregnanolone (clinical API) and established compliant processes to ensure material requirements are met for the preclinical and clinical studies. Manufacture of clinical API will be conducted at the UC Davis CIRM GMP facility.
- 4) FDA required preclinical IND-enabling research strategy was developed. Teams at USC and a California-based CRO, were identified to conduct three studies: 1) Bridging Study: subcutaneous to IV dosing and administration to bridge from previous subcutaneous preclinical analyses to clinical studies using IV APα administration to determine a) optimal IV dose to promote neurogenesis and b) optimal infusion rate to achieve required peak of APα and area under the curve. 2) Cerebral Microhemorrhage: The FDA advised a safety test for the occurrence of cerebral microhemorrhages localized to the cerebral vasculature in areas of cerebral amyloid angiopathy with various anti-Aβ immunotherapies. 3) Chronic GLP Toxicity Analyses: Based on FDA guidance, safety studies will be required for chronic exposure of Alzheimer’s patients to APα. To initiate the chronic exposure Phase 2a Proof of Concept trial, chronic preclinical toxicology is required. We have designed 6-month and 9-month IV dose GLP toxicity studies in rat and dog, respectively. The studies include systemic toxicology and toxicokinetic evaluation.
- 5) In support of developing ideal dosing parameters for the Phase 2 clinical studies, the California CRO, Simulations Plus was utilized. ADMET Predictor™ was used to estimate the biopharmaceutical properties of APα. Predictive modeling of optimal dosing regimen and expected human exposure in Alzheimer’s patients was performed.
- 6) Designed two Phase 2 clinical trials, a Multiple Ascending Dose (MAD) and a Proof of Concept. A California-based CRO, Worldwide Clinical Trials and Alzheimer's clinical trials expert were identified to partner with USC to design and conduct our clinical trials. Phase 2 MAD study primary objectives are to evaluate safety, tolerability and pharmacokinetics. MAD exploratory objectives are to evaluate effect of allopregnanolone on MRI biomarker outcomes and cognition. Proposed MRI biomarkers include hippocampal volume, white matter integrity, and functional connectivity. Phase 2 Proof of Concept trial primary objectives are to evaluate safety and tolerability with long-term exposure. Therapeutic efficacy of allopregnanolone will be determined by outcomes on cognition and biomarkers of regeneration in brain.
- 7) A Steering Committee and Advisory Board were established. Both advisory groups are composed of internationally recognized researchers, translational scientists, regulatory experts and therapeutic development experts. The charge of the Steering Committee is to provide oversight that CIRM allopregnanolone team progress is on track to meet milestones, ensure that processes and strategies are aligned. The Advisory Board is comprised of internationally recognized experts in Alzheimer’s disease and experts in stem cell biology. Advisory Board members will provide an objective evaluation of CIRM allopregnanolone project progress. The functions of Advisory Board are: 1) Advise CIRM allopregnanolone project leadership on identifying key milestones; 2) Review progress on meeting milestones and hitting development targets; 3) Provide strategic and tactical counsel to the Leadership team and Steering Committee.
- 8) Generated viable commercial potential through partnership with SAGE Therapeutics. Ensured patent progression and prosecution through USC. Engaged key opinion leaders in the field and educated these experts regarding therapeutic potential of allopregnanolone as a first in class drug for neuroregeneration in Alzheimer's disease.
This project aims to use a powerful combined stem cell and gene therapy approach to treat patients with amyotrophic lateral sclerosis (ALS or Lou Gehrig’s Disease). ALS is a devastating disease for which there is no treatment or cure. Progression from early muscle twitches to complete paralysis and death usually happens within 4 years. Every 90 minutes someone is diagnosed with ALS in the USA, and every 90 minutes someone dies from ALS. In California the death rate is one person every one and a half days.
Stem cells have been shown to produce support cells for dying motor neurons called astrocytes which may slow down disease progression. Furthermore, many studies have shown that growth factors such as glial cell line-derived growth factor (or GDNF) can protect motor neurons from damage in a number of different animal models including those for ALS. However, delivering GDNF to the spinal cord has been almost impossible as it does not cross from the blood to the brain tissue. The idea behind the current proposal is to modify stem cells to produce GDNF and then transplant these cells into patients. A number of advances in human stem cell biology along with new surgical approaches has allowed us to put together this disease team approach – a first in man study to deliver cells modified to release a powerful growth factor that are expected to slow down the death of motor neurons and paralysis in patients.
The focus of the proposal will be to perform essential preclinical studies in both small and large animals that will establish optimal doses and safe procedures for translating this stem cell and gene therapy into human patients. The Phase 1 clinical study will include 30 ALS patients from the state of California. This will be the first time this type of stem cell and gene therapy has been available to any ALS patients in the world.
ALS is a devastating disease, and also puts a large burden on state resources through the need of full time care givers and hospital equipment. It is estimated that the cost of caring for an ALS patient in the late stage of disease while on a respiration is $200,00-300,000 per year. While primarily a humanitarian effort to avoid suffering, this project will also ease the cost of caring for ALS patients in California if ultimately successful. As the first trial in the world to combine stem cell and gene therapy it will make California a center of excellence for these types of studies. This in turn will attract scientists, clinicians, and companies interested in this area of medicine to the state of California thus increasing state revenue and state prestige in the rapidly growing field of Regenerative Medicine.
- We completed the planning for submission of the CIRM Disease Team Grant on time. The series of meetings we had with leaders in the field of translational medicine as it relates to using stem cells secreting GDNF to treat ALS was extremely useful and allowed us to progress towards a very structured plan for both cell production, pre-clincial animal IND enabling studies and the final clinical trial involving 3 different institutions.
We proposes to use human embryonic stem cells (hESCs) differentiated into neural progenitor/stem cells (NPCs), but modified by transiently programming the cells with the transcription factor MEF2C to drive them more specifically towards dopaminergic (DA) neurons, representing the cells lost in Parkinson’s disease. We will select Parkinson’s patients that no longer respond to L-DOPA and related therapy for our study, because no alternative treatment is currently available. The transplantation of cells that become DA neurons in the brain will create a population of cells that secrete dopamine, which may stop or slow the progression of the disease. In this way, moderate to severely affected Parkinson’s patients will benefit.
The impact of development of a successful cell-based therapy for late-stage Parkinson’s patients would be very significant. There are approximately one million people in the United States with Parkinson’s disease (PD) and about ten million worldwide. Though L-DOPA therapy controls symptoms in many patients for a period of time, most reach a point where they fail to respond to this treatment. This is a very devastating time for sufferers and their families as the symptoms then become much worse. A cell-based therapy that restores production of dopamine and/or the ability to effectively use L-DOPA would greatly improve the lives of these patients. Because of our extensive preclinical experience and the clinical acumen of our Disease Team, we will be able to quickly adapt our procedures to human patients and be able to seek an IND from the FDA within four years.
It is estimated that the cost per year for a Parkinson’s patient averages over $10,000 in direct costs and over $21,000 in total cost to society (in 2007 dollars). With nearly 40 million people in California and with one in 500 estimated to have Parkinson’s (1.5-2% of the population over 60 years of age), there are approximately 80,000 people in California with Parkinson’s disease. Thus, Parkinson’s disease is a significant burden to California, not to mention the devastating effect on those who have the disease and their families. A therapy that could halt the progression or reverse Parkinson’s disease would be of great benefit to the state and its residents. It would be particularly advantageous if the disease could be halted or reversed to an early stage, since the most severe symptoms and highest costs of care are associated with the late stages of the disease. Cell-based therapies offer the hope of achieving this goal.
- A distinguished group of scientists was assembled by Dr. Stuart Lipton to plan a strategy to develop a human embryonic stem cell line expressing a constitutively active form of the transcription factor MEF2 (MEF2CA) into a therapeutic for treatment of Parkinson’s disease (PD), as funded by this planning grant. Preliminary data presented showed directed differentiation of the stem cells into mature dopaminergic cells and a positive outcome, histologically, electrophysiologically and behaviorally, when transplanted into a rat model. The salient features of the preliminary data show that the cells showed a strong propensity to differentiate into dopaminergic neurons, remaining endogenous dopaminergic neurons were saved from death or recruited to synthesize more dopamine through trophic interactions, and the behavioral readout showed that the rats’ neuromotor deficits were improved. An additional feature of the transplanted cells produced by the presented strategy was that none of the MEF2CA-expressing cells were hyperproliferative, indicating that tumor formation will not be a problem with their use. A strategy to further develop the cells under GMP conditions, test in rat and monkey models of PD and begin regulatory compliance for FDA approval was developed. Importantly, insertion of the Mef2CA gene in the stable stem cell line was verified by sequencing to occur at non-essential site of integration.
Alzheimer’s disease (AD) is an incurable disorder that affects memory, social interaction and the ability to perform everyday activities. In the USA alone, the number of AD patients aged 65 and older has surpassed 5 million and that number may triple by 2050. Annual health care costs have been estimated to exceed 172 billion dollars, but do not reflect loss of income and stress caused to caregivers. Therefore, there is great hope for new therapies that will both improve symptoms and alleviate suffering.
There are few FDA-approved medications to treat AD and none is capable of preventing, delaying onset or curing AD. Current medications mostly tend to temporarily slow the worsening of AD-associated symptoms such as sleep disturbances, depression and memory loss/disorientation. Pharmaceutical companies continue to develop new types of drugs or combination therapies that can better treat the symptoms or improve the quality of life of AD patients. There is also an ongoing effort to discover novel drugs that may prevent, reverse, or even cure AD. Unfortunately, the number of clinical studies addressing the possible benefit of such drugs is low, and agents that have shown initial promise have failed at later stage clinical testing, despite convincing preclinical data. There are ongoing studies in AD patients using vaccines and other biological compounds but it is unclear when data from these new trials will be available and more importantly, whether they will be successful. The need for divergent and innovative approaches to AD is clearly suggested by the failure of experimental drugs.
Our proposal is to use brain stem cells to treat AD. This is a completely different approach to the more standard therapies described above such as drugs, vaccines, etc., and one that we hope will be beneficial for AD patients as a one-time intervention. AD is characterized by a dysfunction and eventual loss of neurons, the specialized cells that convey information in the brain. Death or dysfunction of neurons results in the characteristic memory loss, confusion and inability to solve new problems that AD patients experience. It is our hope that stem cells transplanted into the patient’s brain may provide factors that will protect neurons and preserve their function. Even a small improvement in memory and cognitive function could significantly alter quality of life in a patient with AD.
Of the 5.4 million Americans affected with AD, 440,000 are California residents and, according to the Alzheimer’s Association, this number is projected to increase between 49.1 - 81.0% (second highest only to Northwestern states) between 2000 and 2025. Given that California is the most populous state, AD’s impact on state finances is proportionally high and will only increase as the population ages and AD incidence increases. The dementia resulting from this devastating disease disconnects patients from their community and loved ones by eroding memory and cognitive function. Patients gradually lose their ability to drive, work, cook and even carry out simple everyday tasks, and become totally dependent on others. The quality of life of AD patients is hugely affected and the burden on their families and caregivers is very costly to the state of California.
There is no cure for AD and no way to prevent it. Most approved therapies only address symptomatic aspects of AD and disease modifying drugs are currently not available. By enacting Proposition 71, California voters acknowledged and supported the need to investigate the use of novel stem cell based therapies to treat currently incurable diseases such as AD. Our goal is to leverage our proven expertise in developing neural stem cell based therapies for human neurodegenerative disorders and apply it to AD. We propose that neural stem cell transplantation into select regions of the brain will have a beneficial impact on the patient. If successful, a single intervention may be sufficient to delay or stop progression of neuronal degeneration and preserve functional levels of cognition and memory. In a disease such as AD, any therapy that can exert even a modest impact on the patient’s ability to carry out some daily activities will have an exponential positive effect not only on patients but also on families, caregivers and the health care system.
The potential economic impact of such type of therapeutic intervention for California could be tremendous, not only by reducing the high costs of care but also by becoming a vital world center for stem cell interventions in AD.
- Alzheimer's disease (AD) is an incurable disorder that affects memory, social interaction, and the ability to perform everyday activities. The number of AD patients older than 65 has surpassed 5 million in the US and 600,000 in California, numbers that may triple by 2050. Annual health care costs related to AD have been estimated to exceed $172 billion in the US, even without reflecting either the loss of income or the physical and emotional stress experienced by caregivers. Efforts to discover novel and effective treatments for AD are ongoing, but unfortunately, the number of active clinical studies is low and many traditional approaches have failed in clinical testing. There is a great need for new therapies that will both improve symptoms and alleviate suffering.
- AD is characterized by the dysfunction and eventual loss of neurons, the specialized cells that convey information in the brain. Death or dysfunction of neurons results in the characteristic memory loss, confusion, and inability to solve new problems that AD patients experience.
- StemCells Inc. is embarking on an initiative to evaluate the use of its proprietary human neural stem cells to treat AD. We believe that neural stem cells transplanted into a patient’s brain may protect neurons and preserve their function. This represents an entirely new approach to standard therapeutic drug development for AD, which has so far resulted in drugs that only temporarily alleviate symptoms in some patients but that do not slow or change the course of the disease. We envision using neural stem cells as a one-time intervention that will improve memory and cognitive function in AD patients. Even a modest improvement in these symptoms could significantly alter the quality of life of a patient with AD.
- StemCells Inc. received a Disease Team Planning (DTP) award from CIRM to establish a Disease Team for AD, and to begin organizing the activities required to submit a Disease Team Therapy Development (DTTD) award. We are reporting now on the successful completion of this DTP award. The main deliverables were (i) submission of a DTTD award application and (ii) development of a four year research plan that contemplates an Investigational New Drug (IND) submission to the FDA for the clinical study of neural stem cells in patients with AD, within four years.
- To begin evaluating its proprietary human neural stem cells as a potential therapy for AD, StemCells Inc. and its collaborators from UC Irvine needed to first design IND-enabling safety and efficacy studies to test these stem cells in animal models relevant for AD. The DTP funding from CIRM helped support a series of telephone, email and face-to-face meetings over the last 6 months, between investigators at UCI and StemCells Inc., to present and evaluate existing data on neural stem cells and to share information about AD in order to design pilot and definitive efficacy and safety studies. During this time, the team also discussed the logistical details required to conduct these studies.
- After a draft research plan had been outlined, StemCells Inc. and its principal collaborator at UCI, Dr. Frank LaFerla, enlisted the help of various experts in the field of AD, including both clinicians and academic scientists, to evaluate this plan. These experts attended a meeting at UCI and provided input into the experimental design of efficacy and safety studies. Many of these experts were also recruited by StemCells Inc. to participate in preclinical and clinical working groups hosted by the Company. These working groups will ultimately evaluate the preclinical experimental results and help design the protocol for the proposed clinical trial.
- The DTP award also allowed StemCells Inc. to establish a “Project Team” consisting of highly trained and skilled personnel at UCI, StemCells Inc., and an established Contract Research Organization. This Project Team will be responsible for the production and supply of the human neural stem cells, the execution of all efficacy and safety studies, and the preparation and submission of IND documents to the FDA within the next 4 years.
- Finally, the DTP award allowed StemCells Inc. to timely develop and submit its DTTD application to CIRM, in which the Company requested funding in the amount of up to $20 million to facilitate execution of IND-enabling safety and efficacy studies for its proposed breakthrough neural stem cell treatment for AD.
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.
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.
- 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.
The proposed project is designed to assess the safety and preliminary activity of escalating doses of human embryonic stem cell (hESC) derived oligodendrocyte progenitor cells for treatment of spinal cord injury. Oligodendrocyte progenitor cells have two important functions: they produce neurotrophic factors which stimulate the survival and growth of neurons (nerve cells) after injury, and they mature in the spinal cord to produce myelin, the insulation which envelops neuronal axons (nerve cell bodies responsible for conduction) and facilitates unimpeded nerve impulse conduction. After extensive efficacy and safety testing, clinical testing of this product was initiated in 2010.
Clinical testing is being initiated in paraplegic patients with neurologically complete thoracic injuries (i.e., those in which no motor or sensory function remains below the level of the injury). In the first cohort, a dose equivalent to the lowest efficacious dose observed in preclinical rodent studies is being administered. During the course of the proposed program, clinical safety studies testing increasing doses will be conducted. Upon demonstration of safety, clinical testing will be expanded to tetraplegic patients (complete cervical injuries) and to patients with incomplete thoracic injuries for additional safety testing. In each of the proposed studies, preliminary evidence of activity will be monitored using measures of improved neurological function and performance of daily living activities.
The project plan also includes the manufacture of cells to be used in the clinical trials and additional supporting activities. By completion of the proposed project, we expect to have accumulated substantial safety data and preliminary efficacy data in three different patient subpopulations. This data will provide key information to inform the design and execution of advanced efficacy studies.
The proposed project has the potential to benefit the state of California through 1) providing improved medical outcomes for patients with spinal cord injury and their families, 2) increasing California’s leadership in the emerging field of stem cell research, and 3) preserving and creating high quality, high paying jobs for Californians.
Over 12,000 Americans suffer spinal cord injuries each year, and approximately 1.3 million people in the US are estimated to be living with spinal cord injuries. Although specific estimates for the state of California are not available, it is known that the majority of spinal cord injuries result from motor vehicle accidents, falls, acts of violence and recreational sporting activities, all of which are prevalent in California. Spinal cord injury affects not only the patient but family members, friends, healthcare workers and employers. It is estimated that one year after injury, only 11.6% of spinal cord injury patients are employed, and that spinal cord injuries cost $40.5 billion annually in the US. As the most populous state, California is disproportionately affected, negatively impacting our productivity, healthcare system and public finances. There are currently no approved therapies for the treatment of spinal cord injury. The product described in this application has initiated phase 1 clinical testing in patients with complete thoracic spinal cord injury. Even partial correction of any of the debilitating consequences of spinal cord injury could potentially enhance activities of daily living and increase employment while decreasing reliance on attendant care and subsequent medical interventions.
California has a history of leadership in biotechnology, and is emerging as a leader in the development of stem cell therapeutics. Cutting edge stem cell research, in many cases funded by CIRM, is already underway in academic research laboratories and biotechnology companies throughout the state. The proposed project has the potential to further increase California’s leadership in the field of stem cell therapeutics through the performance of the first clinical testing of an hESC-derived therapy.
The applicant has been located in California since its inception, and currently employs 182 full-time employees at its California headquarters with more than 50% of employees holding an advanced degree. These positions are highly skilled positions, offering competitive salaries and comprehensive benefits. The successful performance of the proposed project would enable significant additional jobs creation in preparation for pivotal trials and product registration.
The goal of this research is to utilize novel research tools to investigate the molecular mechanisms that cause Parkinson’s disease (PD). The proposed work builds on previous funding from CIRM that directed the developed patient derived models of PD. The majority of PD patients suffer from sporadic disease with no clear etiology. However some PD patients harbor specific inherited mutations have been shown to cause PD. The most frequently observed form of genetic parkinsonism is caused by the LRRK2 G2019S mutation it the most common. This mutation accounts for approximately 1.5-2% of patients with apparently sporadic PD, increasing to 4-6% of patients with a family history of PD, and even higher in isolated populations. Importantly, LRRK2 induced PD is clinically and pathologically largely indistinguishable from sporadic PD.
This proposal focuses on studying the most frequent cause of familial PD and induces disease that is clinically and pathologically identical to sporadic PD cases. It is likely that LRRK2 regulates a pathway(s) that is important in the more common sporadic form of PD as well. Therefore by employing relevant models of PD, we hope to drive the biological understanding of LRRK2 in a direction that facilitates the development of disease therapeutics in the future. We ascertained patients harboring mutations in LRRK2 [heterozygous (+/G2019S) and homozygous (G2019S/G2019S)] as well as sporadic cases and age matched controls. We have successfully derived iPSCs from each genotype and differentiated these to DA neurons. We will use these as a model system to investigate these LRRK2 based models of PD.
We will adapt current biochemical assays of LRRK2, which are source material intensive, to the small culture volumes required for the differentiation of iPSCs to DA neurons. This is a crucial necessity for development for utilizing iPSC derived DA neurons as tractable models of LRRK2 based PD. We will then probe the roles of LRRK2 in neuronal cell differentiation and survival. We will also ask whether the mutant LRRK2 induces changes in autophagy, as this has been postulated as a mechanism of LRRK2 induced pathogenesis. By studying wild-type and disease mutant LRRK2, in DA models of PD we hope to provide crucial understanding of the role mutant LRRK2 has in disease.
It is estimated that by the year 2030, 75,000-120,000 Californians will be affected by Parkinson’s disease. Currently, there is no cure, early detection mechanism, preventative treatment, or effective way to slow disease progression. The increasing disability caused by the progression of disease burdens the patients, their caregivers as well as society in terms of healthcare costs. The majority of PD patients suffer from sporadic disease with no clear etiology, and a in a handful of these patients specific inherited mutations have been shown to cause PD. The most frequently mutated gene is called Leucine Rich Repeat Kinase 2 (LRRK2). Our goal is to study the mutated gene product in patient based models of Parkinson’s disease.
In previous CIRM funding, we have developed patient derived induced pluripotent stem cells (iPSCs) from patients harboring mutations in LRRK2. We have been successful in differentiating populations these iPSCs into the neurons that are depleted in PD. The next step is to utilize these cells as models of mutation induced PD ‘in a dish’. We will employ these pertinent disease models to answer basic biology questions that remain about the function of LRRK2.
This project brings together scientists previously funded by CIRM with scientists well versed in the study of LRRK2. This multidisciplinary approach to studying the causes of PD is a natural benefit to the State of California and its citizens. By bringing a better understanding of the role of LRRK2 in the cells that are lost in the progression of PD, we will bring more concrete knowledge of PD as a whole, bringing more hope for the development of a therapeutic for disease.
- The overarching goal of this work is to utilize models of Parkinson's disease (PD) that originate from cells of PD affected patients harboring mutations within the LRRK2 gene so that we may discern the role of mutated LRRK2 in disease. Mutations in LRRK2 are the most common cause of familial PD. The disease presentation of patients with LRRK2 mutation is typically clinically indistinguishable from sporadic PD cases, making the onset of disease due to LRRK2 dysfunction clinically relevant. We have employed stem cells derived from these patients to generate neuronal cells in which we can determine the roles of LRRK2 in the PD mutated and the unmutated state. We have focused on a cellular process called autophagy that regulates the cell response to nutrient deprivation and plays a role in the selective degradation of proteins within the cell.
- In the first year of funding we have analyzed the expression of the protein LRRK2 in induced pluripotent stem cells, neuronal precursor cells and have begun to differentiate the neuronal precursors to dopaminergic cells of the type lost in PD (a difficult task in itself). We have applied a novel method for detection of LRRK2 in situ by marrying the protein detection of antibodies and the sensitivity of nucleic acid amplification. We will continue to develop this methodology for maximum sensitivity to LRRK2. We have established assays to assess the effects of the LRRK2 mutant on autophagy that are relevant to PD and neurological diseases in general. We have met or made great progress on most of our anticipated milestones and are eager to proceed to the next phase of the project.
- The overarching goal of this work is to utilize stem cell based models of Parkinson's disease (PD) derived from cells of PD affected patients that harbor mutations in the LRRK2 gene so that we may elucidate the deleterious role of mutated LRRK2 in disease. Mutations in LRRK2 are the most common cause of familial PD. The disease presentation for these patients with LRRK2 mutation is typically clinically similar to those with sporadic disease, making the onset of disease due to LRRK2 dysfunction clinically relevant. We have utilized stem cells harboring a mutation in LRRK2 and also daughter cells of that line in which genomic editing techniques have been applied to correct the PD mutation or disrupt the LRRK2 gene. We have generated the same kind of cells in culture that are lost during PD and hope that next, we can determine how these mutations that eventually cause disease disrupt normal neuronal function. We have made great progress in the understanding the expression of LRRK2 in early differentiation of stem cells to neurons and his will inform our future studies on mutation caused dysfunctions.
- The overarching goal of this work is to utilize stem cell based models of Parkinson's disease (PD) derived from cells of PD affected patients that harbor mutations in the LRRK2 gene so that we may elucidate the deleterious role of mutated LRRK2 in disease. Mutations in LRRK2 are the most common cause of familial PD. The disease presentation for these patients with LRRK2 mutation is typically clinically similar to those with sporadic disease, making the onset of disease due to LRRK2 dysfunction clinically relevant. We have utilized stem cells harboring a mutation in LRRK2 and also daughter cells of that line in which genomic editing techniques have been applied to correct the PD mutation or disrupt the LRRK2 gene. We have generated the same kind of cells in culture that are lost during PD and hope that next, we can determine how these mutations that eventually cause disease disrupt normal neuronal function. We have made great progress in the understanding the expression of LRRK2 in early differentiation of stem cells to neurons and this will inform our future studies on mutation caused dysfunctions.
- During our project we achieved several scientific goals. Our project was to utilize Parkinson’s disease patient derived stem cells to model their disease. The particular cells we used were derived from patients with mutations in the LRRK2 gene, which is the most common cause of inherited Parkinson’s disease. At the end of our funding we can report proficiency in induced pluripotent stem cell (iPSC) differentiation to dopaminergic cells protocols in a workflow that allows higher throughput analysis. Dopaminergic cells are types of cells lost in the brain in Parkinson’s disease and if we study cells from patients with this mutation it will likely yield insight into the processes of disease onset and progression. This funding enabled collaboration with the laboratory of Dr. Schuele here at the Parkinson’s Institute to use cells generated in other CIRM funding (ETI-0246 and RT2-019665). The cell lines we used were edited to “fix” the genetic mutation in the LRRK2 gene and also to delete (or knockout) the LRRK2 gene. We used these cells and determined that loss of LRRK2 imparts an increased propensity for dopaminergic differentiation potential for knockouts over mutant and wild-type cells. Also, we determined that LRRK2 inhibitors do not negatively impact the generation of dopaminergic cells in cell culture modeling. We will continue to unravel the roles of LRRK2 in Parkinson’s disease using these pertinent, patient centric models.
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.
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.
- 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.
- 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 focused on hiPSCs from the related TNR diseases myotonic dystrophy type 1 (DM1), Huntington's disease (HD), Fragile X syndrome (FXS), and Fuchs endothelial corneal dystrophy (FECD). DM1 is an inherited dominant muscular dystrophy caused by expanded CTG•CAG triplet repeats in the DMPK 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. hiPSCs were generated from DM1 and HD patient fibroblasts. Similar to our results in FRDA, DM1 hiPSCs show repeat instability, and repeat expansion is again dependent on the DNA mismatch repair system. We defined a threshold of repeat lengths where repeat expansion occurs. The relatively short repeats in the gene responsible for Huntington's disease are below this threshold and hence do not expand in the iPSCs. 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. In recent studies, we have turned our attention to the common eye disease FECD, where ~75% or so of Caucassian patients have a CTG•CAG triplet-repeat in an intron of the gene encoding the essential transcription factor TCF4. We find repeat instability in fibroblasts from FECD patient fibroblasts, and repeat expansion in the corresponding hiPSCs. Importantly, similar to DM1 with the same repeat sequence as in FECD, the pathological mechanism in both diseases appear to be similar, namely RNA toxicity caused by sequestering essential messenger RNA processing factors. We have also identified a potential small molecule therapeutic that binds CTG•CAG triplet-repeats and are currently testing this molecule in the relevant patient iPSC-derived cell types. The information gained from these studies provides new insight into a general mechanism of triplet repeat expansion in iPSCs and has revealed a new therapeutic approach for these diseases.
Autism spectrum disorders (ASD) are a group of neurodevelopmental diseases that occur in as many as 1 in 150 children in the United States. Three hallmarks of autism are dysfunctional communication, impaired social interaction, and restricted and repetitive interests and activities. Even though no single genetic defect has been ascribed to having a causative role in the majority of ASD cases, twin concordance studies and rare familial forms of the disease strongly support a genetic malfunction and a combinatorial effect of genetic risk factors may contribute to the variability in the symptoms. One major obstacle to ASD research is the difficulty in obtaining human neural tissue to model the disease in vitro. Mouse models of ASD are limited since only rare genetic mutations have been identified so far, and single mutations in those genes cannot fully reproduce the range of critical behaviors characteristic of ASD. Direct reprogramming of patient tissues to induced pluripotent stem (iPS) cells and derivation of forebrain neurons from them will provide much needed insight into the molecular mechanism of neuronal dysfunction in diverse individuals on the autism spectrum. The use of patient-derived stem cells to characterize cellular defects brings together two investigative approaches. One is the identification of common cellular and molecular mechanisms that are central to deficiencies across diverse populations of patients. The other is quantitative comparison of pathological features that address differences amongst diverse patients. Our major goal is to characterize the synaptic dysfunction using concrete, quantifiable parameters in human neurons that have specific mutations in key synaptic proteins. This approach will give us a handle into the molecular synaptic complexes that may also be altered in sporadic ASD cases and could help us develop drug strategies that can normalize synaptic function. Although several groups are interested in generating iPS cells from autistic patients, these efforts generally do not have genomic information on the patients, and the large diversity of mutations associated with autism could lead to large variation in synaptic phenotypes. By focusing on generating iPS cells from patients carrying mutations in a small number of critical synaptic proteins and characterizing the molecular components of this complex, we are likely to be in a strong position to identify novel molecular defects associated with autistic synapses. Relative biochemical comparisons of wildtype and mutant protein complexes could help us find ways to restore synaptic function in ASD.
Many children in California are affected by autism spectrum disorders, which include monogenic syndromes such as Fragile X syndrome and Rett syndrome. However, the majority of cases are idiopathic and an interplay of multiple genetic risk factors is suspected. Since no current drug therapies exist for autism and an accurate diagnosis can only be made in early childhood by largely behavioral criteria, the cost of care and social burden for such a disorder is high, not to mention the devastation to the quality of life for the families of affected children. We would like to identify a core set of proteins found in synapses that are disrupted or dysregulated in autism by a biochemical approach. If we succeed in this effort, we may be able to identify novel biomarkers and molecular targets for specific patient profiles, and by cross-correlating the genetic background to specific behavioral traits in specific individuals, we may come up with molecular targets that are able to address particular symptoms, which should greatly aid in therapeutic regimens that complement existing behavioral therapies. Generating iPS neurons with known copy number variations associated with autism would be a major resource for other laboratories in California and in the field in general. The economic benefit to California is manifold, as many pharmaceutical and biotech companies in California will want to exploit these novel cell lines and the therapeutic targets identified through them in order to design better drugs for autism.
- The main goal of this project is to establish a cell culture model human neuronal model of autism spectrum disorders (ASD) by generating induced pluripotent stem (iPS) cell lines from patients harboring mutations in genes associated with autism, differentiating them into forebrain neurons, and characterizing their synaptic defects at the cellular and molecular level. We have successfully obtained iPS cells from two autism spectrum disorders, tuberous sclerosis complex (TSC) and Rett syndrome (RTT). We obtained fibroblasts from patients with mutations in the TSC1 and TSC2 genes through the Coriell biorepository. We then reprogrammed them into several TSC patient-specific iPS cell lines. Furthermore, we have obtained male MECP2 mutant iPS cell lines from the lab of Dr. Alysson Muotri to study in parallel with the TSC lines.
- We differentiated ASD iPS cell lines into neural progenitor cell (NPCs) and have been examining differences in protein levels and signaling pathways in these cells. Pathway analyses from MECP2 mutant NPCs suggest there may be a marked deficit in several major intracellular signaling pathways, and we are validating those deficits by biochemical analyses and genetic manipulations. Both TSC and RTT forebrain neurons show significant differences in synaptic regulation compared to their respective controls. Alterations in synaptic regulation are being assessed by gene expression analysis, staining for synaptic markers, and electrophysiology. We have made major progress toward realizing our goal of establishing novel iPS cell models for ASD. Furthermore, we obtained very interesting data that should help us elucidate the cell signaling deficits that lead to neuronal dysfunction.
- We set out to establish an in vitro human neuronal model of autism spectrum disorders (ASD) by generating induced pluripotent stem (iPS) cell lines from patients harboring specific genetic mutations in syndromic forms of autism, such as Rett Syndrome (RTT) and Tuberous sclerosis (TS). We then differentiated them into neural progenitor cells (NPCs) and forebrain neurons, in order to compare their differentiation potential and to characterize mutation-associated deficits at the cellular and molecular level. Previously published data on cellular and animal models indicate that synaptic deficits are a major feature of the pathophysiology of RTT and TS.
- We employed patient-derived induced pluripotent stem cells (iPSCs) from male RTT patients and gender-matched parental controls to probe for functional and molecular deficits in RTT. A similar approach was taken for TS.
- As MECP2 is expressed in both the developing and mature central nervous system, we investigated deficits that may arise during early developmental stages (i.e. at the neural progenitor cell or NPC stage), which could then significantly affect neurodevelopmental processes such as neurogenesis and gliogenesis. By quantitative proteomics, we showed that the RTT cells have changes on the molecular level, at both the NPC and neuron stage, compared to their WT control, and that these changes may reflect some of the deficits in the developmental process. We report delays in maturation, such as misregulation of LIN28 at the NPC stage and subsequent deficits in glial differentiation.
- Taken together, these results provide a framework for identifying novel early pathways that are perturbed in RTT, as well as potential therapeutics to minimize functional deficits. More generally, it will be of interest to see if these pathways and possible therapeutics may carry over to other related forms of neurodevelopmental disorders, in particular, idiopathic autism.
Induced pluripotent stem cells (iPSCs) have tremendous potential for patient-specific cell therapies, which bypasses immune rejection issues and ethical concerns for embryonic stem cells (ESCs). However, to fully harness the therapeutic potential of iPSCs, many fundamental issues of cell transplantation remain to be addressed, e.g., how iPSC-derived cells participate in tissue regeneration, which type of cells should be derived for specific therapy, and what kind of matrix is more effective for cell therapies. The goal of this project is to use iPSC-derived neural crest stem cells (NCSCs) and nerve regeneration as a model to address these fundamental issues of stem cell therapies. NCSCs are multipotent and can differentiate into cell types in all three germ layers (including neural, vascular, osteogenic and chondrogenic cells), which makes NCSC a valuable model to study stem cell differentiation and tissue regeneration. Peripheral nerve injuries and demyelinating diseases (e.g., multiple sclerosis, familial dysautonomia) affect millions of people. Stem cell therapy is a promising approach to cure these diseases, which will have broad impact on healthcare.
This project will advance our understanding of how extracellular microenvironment (native or engineered) regulates stem cell fate and behavior during tissue regeneration, and whether stem cells such as iPSC-NCSCs and differentiated cells such as iPSC-Schwann cells have different therapeutic effects. The results from this project will provide insights that will facilitate the translation of stem cell technologies into therapies for nerve injuries, demyelinating diseases and many other disorders that may be treated with iPSC-NCSCs.
Induced pluripotent stem cells (iPSCs), especially iPSCs without the integration of reprogramming factors into the genome, are valuable to model disease and to generate autologous cells for therapies. Understanding the role and differentiation of iPSC-derived cells in tissue regeneration will facilitate the translation of stem cell technologies into clinical applications.
iPSC-derived neural crest stem cells (NCSCs) can differentiate into a variety of cell types, and hold promise for the therapies of diseases such as nerve injuries, demyelinating diseases, spina bifida, vascular diseases, osteoporosis and arthritis. The isolation and characterization of iPSC-NCSCs will provide a basis for their broad applications in tissue regeneration and disease modeling.
This project will use peripheral nerve regeneration as a model to address the fundamental issues of using iPSC-NCSCs for therapies. Peripheral nerve injuries (over 800,000 cases in the United States every year) are very common following traumatic injuries and major surgeries (e.g., removing tumor), which often require surgical repair. Stem cell therapies can accelerate nerve regeneration and avoid the degeneration of muscle and other tissues lack of innervation. Since iPSC-NCSCs can promote the myelination of axons, the therapies for nerve injuries could also be adopted to treat demyelinating diseases.
In many cases of stem cell therapies, matrix and scaffold materials are needed to enhance cell survival and achieve local delivery. The studies on appropriate matrix for stem cell delivery will provide a rational basis for designing and optimizing materials for stem cell therapies.
The fundamental issues addressed in this project, such as the differentiation and signaling of transplanted cells, the therapeutic effects of cells at the different stages of differentiation and the roles of delivery matrix/materials, will have implications for stem cell therapies in many other tissues.
Overall, the results from this project will advance our knowledge on stem cell differentiation and function during tissue regeneration, help us translate the knowledge into clinical applications, and benefit the health care in California and our society.
- Induced pluripotent stem cells (iPSCs) have tremendous potential for regenerative medicine applications. Here we use peripheral nerve regeneration as a model to address the fundamental issues of using iPSCs and their derivatives for therapies. Specifically, we used integration-free iPSCs for our studies because this type of iPSCs has potential for clinical applications. We derived and characterized neural crest stem cells (NCSCs) from integration-free iPSCs, and demonstrated that these NCSCs can differentiate into a variety of cell types, including Schwann cells. We delivered NCSCs into nerve conduits to treat peripheral nerve injuries, and performed functional studies, electrophysiology analysis and histological analysis. Ongoing studies suggest that the transplantation of iPSC-NCSCs accelerate nerve regeneration. To investigate the interactions of transplanted stem cells with endogenous neural progenitors, we isolated and characterized endogenous progenitors from injured nerves, which will be used for mechanistic studies. In addition, we engineered the chemical components and the structure of nerve conduits, and developed and characterized hydrogels that could be used to deliver neurotrophic factors and minimize scar formation. The roles of neurotrophic factors, transplanted/endogenous stem cells and matrix for stem cell delivery will be investigated.
- We use peripheral nerve regeneration as a model to address the critical issues of using induced pluripotent stem cells (iPSCs) and their derivatives for tissue regeneration. In the past year, we have made progress in all three Specific Aims. We generated 5 new integration-free IPSC lines by using episomal reprogramming. We also tested the methods of using biomaterials and chemical compounds to reprogram cells, in the presence or absence of transcriptional factors. We have derived and characterized additional neural crest stem cell (NCSC) lines from these new iPSC lines, and demonstrated that these NCSCs are multipotent in their differentiation potential. To investigate the mechanisms of how NCSCs enhanced the functional recovery of transected sciatic nerves, we examined the effects of paracrine signaling, cell differentiation and matrix stiffness. In vivo experiments showed that transplanted cells secreted neurotrophic factors to promote axon regeneration. In addition, NCSCs differentiated into Schwann cells to enhance myelination. The stiffness of extracellular matrix (ECM) indeed has effect on NCSC differentiation.
- Here we use peripheral nerve regeneration as a model to address the critical issues of using induced pluripotent stem cells (iPSCs) and their derivatives for tissue regeneration. In the past year, we have made progress in all three Specific Aims, as detailed below. In Specific Aim 1, we generated 5 new integration-free IPSC lines by using episomal reprogramming. We also optimized the protocol to derive neural crest stem cells (NCSCs) from integration-free human iPSCs, and fully characterized the derived cells. Transplantation of selected NCSC lines significantly improved the functional recovery of peripheral nerve following injury. In addition, transplanted NCSCs differentiated into Schwann cells around regenerated axons. Nerve growth factor (NGF) appeared to be a major neurotrophic factor expressed by NCSCs, which was involved in nerve regeneration. In Specific Aim 2, we derived and characterized Schwann cells from NCSCs. Transplantation of NCSCs or Schwann cells showed that NCSC transplantation had better functional recovery than Schwann cell transplantation, suggesting that the differentiation stage of transplanted cells is critical for stem cell therapies. In Specific Aim 3, we demonstrated that the soft matrix worked much better than stiffer matrix for NCSC delivery and the functional recovery of damaged nerve. A new direction for this Specific Aim is a ground-breaking finding that matrix stiffness regulates the direct reprograming of fibroblasts into neurons, which has applications in generating neurons for drug discovery and disease modeling. Overall, our findings underline the importance of stem cell differentiation stage and biomaterials property in stem cell therapies, and will have broad impact on using stem cells for nerve regeneration and many other regenerative medicine applications.