Neurological Disorders

Critical to the long term success of the CIRM iPSC Initiative of generating and ensuring the availability of high quality disease-specific human IPSC lines is the establishment and successful operation of a biorepository with proven methods for quality control, safe storage and capabilities for worldwide distribution of high quality, highly-characterized iPSCs. Specifically the biorepository will be responsible for receipt, expansion, quality characterization, safe storage and distribution of human pluripotent stem cells generated by the CIRM stem cell initiative. This biobanking resource will ensure the availability of the highest quality hiPSC resources for researchers to use in disease modeling, target discovery and drug discovery and development for prevalent, genetically complex diseases.

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

Our goal is to use the mechanisms that generate neuronal networks to create neurons from stem cells, to either replace diseased and damaged tissue or as a source of material to study disease mechanisms. A key focus of such regenerative studies is to restore function to the spinal cord, which is particularly vulnerable to damage. However, although considerable progress has been made in understanding how to direct stem cells towards motor neurons that control coordinated movement, little progress has been made so far directing stem cells to form the sensory neurons that allow us to experience the environment around us. Our proposed research will use insights from the mechanisms known to generate the sensory neurons during the development of the spinal cord, to derive these neurons from stem cells. We will initially use mouse embryonic stem cells in these studies, to accelerate the experimental progress. We will then apply our findings to human embryonic stem cells, and assess whether these cells are competent to repopulate the spinal cord. These studies will significantly advance our understanding of how to generate the full repertoire of neural subtypes necessary to repair the spinal cord after injury, specifically permitting patients to recover sensations such as pain and temperature. Moreover, they also represent a source of therapeutically beneficial cells for modeling debilitating diseases, such as the chronic insensitivity to pain.

The proposed alpha clinic will bring together an outstanding team of physician-scientists with substantial clinical trials experience including stem cell and other cellular treatments of blood diseases and others. This team will also draw on our unique regional competitive advantages derived from our history of extensive collaboration with investigators at many nearby first-class research institutions and biotech companies. We propose to include these regional assets in our plans to translate our successful research on basic properties of stem cells to stem cell clinical trials and ultimately to delivery of effective and novel therapies. We propose to build an alpha clinic that serves the stem cell clinical trial needs of our large region where we are the only major academic health center with the needed expertise to establish a high impact alpha clinic. Our infrastructure will initially be developed and then used to support two major high-impact stem cell clinical trials: one in type I diabetes and one in spinal cord injury. Both are collaborations with established and well known companies. The type I diabetes trial will test embryonic stem cell derived cells that differentiate to become the missing beta cells of the pancreas. The cells are contained in a semipermeable bag that has inherent safety because of restriction of cell migration while allowing proper control of insulin levels in response to blood sugar. These hybrid devices are implanted just beneath the skin in patients in these trials. In a second trial of stem cell therapy for spinal cord injury, neuronal stem cells that have been shown to have substantial safety and efficacy in animal models of spinal cord injury and other types of spinal cord trauma or disease will be tested in human patients with chronic spinal cord injury. Both of these trials have the potential to have very substantial and important impact on patients with these diseases and the families and society that supports them. Following on these two trials, we are planning stem cell clinical trials for heart failure, cancer, ALS, and other terrible deadly disorders. Our proposed alpha clinic also benefits from very substantial leveraged institutional commitments, which will allow for an alpha clinic that is sustainable well beyond the five-year grant, which is essential to continue to manage the patients who have participated in the first trials being planned since multi-year followup and tracking is essential scientifically and ethically. We have a plan for our proposed alpha clinic to be sustainable to 10 years and beyond to the point at which these therapies if successful will be delivered to patients in our healthcare system.

Microglia are a type of immune cell within the brain that profoundly influence the development and progression of many neurological disorders. Microglia also inherently migrate toward areas of brain injury, making them excellent candidates for use in cell transplantation therapies. Despite the widely accepted importance of microglia in neurological disease, methods to produce microglia from stem cells have yet to be reported. Our team has recently developed one of the first protocols to generate microglia from human pluripotent stem cells. We have used several approaches to confirm that the resulting cells are microglia including examination of gene expression and testing of key microglial functions. However, our current protocol uses cell culture supplements that preclude the use of these cells for any future clinical applications in people. The major goal of this proposal is to resolve this problem. We will generate pluripotent human stem cells that have special "reporter" genes that make the cells glow as they become microglia, allowing us to readily monitor and quantify the generation of these important cells. Using these reporter lines we can then streamline the differentiation process and develop improved protocols that could be translated toward eventual clinical use. As a proof-of-principle experiment we will then use the resulting human microglia to study some important questions about the genetic causes and potential treatment of Alzheimer’s disease.

Alzheimer’s disease (AD), the leading cause of dementia, results in profound loss of memory and cognitive function, and ultimately death. In the US, someone develops AD every 69 seconds and there are over 5 million individuals suffering from AD, including approximately 600,000 Californians. Current treatments do not alter the disease course. The absence of effective therapies coupled with the sheer number of affected patients renders AD a medical disorder of unprecedented need and a public health concern of significant magnitude. In 2010, the global economic impact of dementias was estimated at $604 billion, a figure far beyond the costs of cancer or heart disease. These numbers do not reflect the devastating social and emotional tolls that AD inflicts upon patients and their families. 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. An urgent need to develop novel and innovative approaches to treat AD is clear. We propose to evaluate the use of human neural stem cells as a potential innovative therapy for AD. AD results in neuronal death and loss of connections between surviving neurons. The hippocampus, the part of the brain responsible for learning and memory, is particularly affected in AD, and is thought to underlie the memory problems AD patients encounter. Evidence from animal studies shows that transplanting human neural stem cells into the hippocampus improves memory, possibly by providing growth factors that protect neurons from degeneration. Translating this approach to humans could markedly restore memory and thus, quality of life for patients. The Disease Team has successfully initiated three clinical trials involving transplantation of human neural stem cells for neurological disorders. These trials have established that the cells proposed for this therapeutic approach are safe for transplantation into humans. The researchers in this Disease Team have shown that AD mice show a dramatic improvement in memory skills following both murine and human stem cell transplantation. With proof-of-concept established in these studies, the Disease Team intends to conduct the animal studies necessary to seek authorization by the FDA to start testing this therapeutic approach in human patients. This project will be conducted as a partnership between a biotechnology company with unique experience in clinical trials involving neural stem cell transplantation and a leading California-based academic laboratory specializing in AD research. The Disease Team also includes expert clinicians and scientists throughout California that will help guide the research project to clinical trials. The combination of all these resources will accelerate the research, and lead to a successful FDA submission to permit human testing of a novel approach for the treatment of AD; one that could enhance memory and save lives.

Clinical application of cell transplantation therapy requires a means of non-invasively monitoring these cells in the patient. Several imaging modalities, including MRI, bioluminescence imaging, and positron emission tomography have been used to track stem cells in vivo. For MR imaging, cells are pre-loaded with molecules or particles that substantially alter the image brightness; the most common such labelling strategy employs iron oxide particles. Several studies have shown the ability of MRI to longitudinally track transplanted iron-labeled cells in different animal models, including stroke and cancer. But there are drawbacks to this kind of labeling. Division of cells will result in the dilution of particles and loss of signal. False signal can be detected from dying cells or if the cells of interest are ingested by other cells. To overcome these roadblocks in the drive toward clinical implementation of stem cell tracking, it is now believed that a genetic labeling approach will be necessary, whereby specific protein expression causes the formation of suitable contrast agents. Such endogenous and persistent generation of cellular contrast would be particularly valuable to the field of stem cell therapy, where the homing ability of transplanted stem cells, long-term viability, and capacity for differentiation are all known to strongly influence therapeutic outcomes. However, genetic labeling or "gene reporter" strategies that permit sensitive detection of rare cells, non-invasively and deep in tissue, have not yet been developed. This is therefore the translational bottleneck that we propose to address in this grant, through the development and validation of a novel high-sensitivity MRI gene reporter technology. There have been recent reports of gene-mediated cellular production of magnetic iron-oxide nanoparticles of the same composition as the synthetic iron oxide particles used widely in exogenous labeling studies. It is an extension of this strategy, combined with our own strengths in developing high-sensitivity MRI technology, that we propose to apply to the task of single cell tracking of metastatic cancer cells and neural stem cells. If we are successful with the proposed studies, we will have substantially advanced the field of in vivo cellular imaging, by providing a stable cell tracking technology that could be used to study events occurring at arbitrary depth in tissue (unlike optical methods) and over unlimited time duration and arbitrary number of cell divisions (unlike conventional cellular MRI). With the ability to track not only the fate (migration, homing and proliferation) but also the viability and function of very small numbers of stem cells will come new knowledge of the behavior of these cells in a far more relevant micro-environment compared with current in vitro models, and yet with far better visualization and cell detection sensitivity compared with other in vivo imaging methods.

Injuries to the spinal cord commonly result from motor vehicle accidents, traumatic falls, diving, surfing, skiing, and snowboarding accidents, other forms of sports injuries, as well as from gunshot injuries in victims of violent crimes. Injuries to the anatomically lowest part of the spinal cord, the lumbosacral portion and its associated nerve roots commonly cause paralysis, loss of sensation, severe pain, as well as loss of bladder, bowel, and sexual function. Lumbosacral injuries represent approximately one-fifth of all traumatic lesions to the human spinal cord. As a result of the direct injury to the lumbosacral portion of the spinal cord, there is degeneration and death of spinal cord nerve cells, which control muscles in the legs as well as bladder, bowel, and sexual function. No treatments are presently available in clinical practice to reverse the effects of these devastating injuries. In order to reverse the loss of function after lumbosacral spinal cord injury, replacement of the lost nerve cells is required. Recent research studies have identified some properties that are shared by spinal cord neurons responsible for muscle and bladder control. Human embryonic stem cells can now be prepared in research laboratories to develop properties that are shared between nerve cells controlling muscle and bladder function. Such nerve cells are particularly at risk of degeneration and death as a result of injuries to the lumbosacral spinal cord. Human embryonic stem cells, which have undergone treatment to obtain properties of muscle and bladder controlling nerve cells, are now very attractive development candidates for new cell replacement therapies after lumbosacral spinal cord injuries. The proposed feasibility studies will study the properties of such cells in a clinically relevant rat model for lumbosacral spinal cord injuries. In Specific Aim 1, we will determine whether ACUTE transplantation of human embryonic stem cells, which have been treated to develop properties of specific lumbosacral spinal cord neurons, may replace lost nerve cells and result in a return of bladder function in a rat model of lumbosacral spinal cord injury and repair. In Specific Aim 2, we will determine whether DELAYED transplantation of human embryonic stem cells, which have been treated to develop properties of specific lumbosacral spinal cord neurons, may replace lost nerve cells and result in a return of bladder function in a rat model of lumbosacral spinal cord injury and repair. A variety of functional studies will determine the effect of the cell transplantation on bladder function, walking, and pain. We will also use detailed anatomical studies to determine in microscopes whether the transplanted cells have grown processes to connect with pelvic target tissues, including the lower urinary tract. If successful, the proposed experiments may lead to a new treatment strategy for patients with lumbosacral spinal cord injuries.

A stroke kills brain cells by interrupting blood flow. The most common “ischemic stroke” is due to blockage in blood flow from a clot or narrowing in an artery. Brain cells deprived of oxygen can die within minutes. The loss of physical and mental functions after stroke is often permanent and includes loss of movement, or motor, control. Stroke is the number one cause of disability, the second leading cause of dementia, and the third leading cause of death in adults. Lack of movement or motor control leads to job loss and withdrawal from pre-stroke community interactions in most patients and institutionalization in up to one-third of stroke victims. The most effective treatment for stroke, thrombolytics or “clot-busters”, can be administered only within 4.5 hours of the onset of stroke. This narrow time window severely limits the number of stroke victims that may benefit from this treatment. This proposal develops a new therapy for stroke based on embryonic stem cells. Because our (and others’) laboratory research has shown that stem cells can augment the brain’s natural repair processes after stroke, these cells widen the stroke treatment opportunity by targeting the restorative or recovery phase (weeks or months after stroke instead of several hours). Embryonic stem cells can grow in a culture dish, but have the ability to produce any tissue in the body. We have developed a technique that allows us to restrict the potential of embryonic stem cells to producing cell types that are found in the brain, making them “neural stem cells”. These are more appropriate for treating stroke and may have lower potential for forming tumors. When these neural stem cells are transplanted into the brains of mice or rats one week after a stroke, the animals are able to regain strength in their limbs. Based on these findings, we propose in this grant to further develop these neural stem cells into a clinical development program for stroke in humans at the end of this grant period. This proposal develops a multidisciplinary team that will rigorously test the effectiveness of stem cell delivery in several models of stroke, while simultaneously developing processes for the precise manufacture, testing and regulatory approval of a stem cell therapy intended for human use. Each step in this process consists of definite milestones that must be achieved, and provides measurable assessment of progress toward therapy development. To accomplish this task, the team consists of stroke physician/scientists, pharmacologists, toxicologists, experts in FDA regulatory approval and key collaborations with biotechnology firms active in this area. This California-based team has a track record of close interactions and brings prior stroke clinical trial and basic science experience to the proposed translation of a stem cell therapy for stroke.

Children with inherited degenerative diseases of the brain will be among the first to benefit from novel approaches based on stem cell therapy (SCT). This assertion is based on a number of medical and experimental observations and precedents including: 1) These diseases currently lack effective therapies and can cause profound mental retardation or lead to death; 2) SCT has already been shown to work in the milder forms of similar diseases that do not affect the brain; 3) Experimental work and early clinical studies have clearly shown that stem cells delivered directly into the brain can be used to treat diseases affecting the brain; and 4) The clinical safety of stem cells delivered directly into the brain has already been established during recent Phase 1 clinical trials. Our approach is designed to lead to a therapeutic development candidate, based on stem cells, by addressing two critical issues: (i) that early intervention is not only required but is indeed possible in this patient population and that, (ii) induction of immune tolerance is also required. We not only address these two important issues but also set the stage for efficient translation of our approach into clinical practice, by adapting transplant techniques that are standard in clinical practice or in clinical trials and using laboratory cell biology methods that are easily transferrable to the scale and processes of clinical cell manufacturing.