Neurological Disorders

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

Misregulated Mitophagy in Parkinsonian Neurodegeneration

Funding Type: 
Basic Biology V
Grant Number: 
RB5-06935
ICOC Funds Committed: 
$1 174 943
Disease Focus: 
Parkinson's Disease
Neurological Disorders
Stem Cell Use: 
iPS Cell
oldStatus: 
Closed
Public Abstract: 
Parkinson’s disease (PD), is one of the leading causes of disabilities and death and afflicting millions of people worldwide. Effective treatments are desperately needed but the underlying molecular and cellular mechanisms of Parkinson’s destructive path are poorly understood. Mitochondria are cell’s power plants that provide almost all the energy a cell needs. When these cellular power plants are damaged by stressful factors present in aging neurons, they release toxins (reactive oxygen species) to the rest of the neuron that can cause neuronal cell death (neurodegeneration). Healthy cells have an elegant mitochondrial quality control system to clear dysfunctional mitochondria and prevent their resultant devastation. Based on my work that Parkinson’s associated proteins PINK1 and Parkin control mitochondrial transport that might be essential for damaged mitochondrial clearance, I hypothesize that in Parkinson’s mutant neurons mitochondrial quality control is impaired thereby leading to neurodegeneration. I will test this hypothesis in iPSC (inducible pluripotent stem cells) from Parkinson’s patients. This work will be a major step forward in understanding the cellular dysfunctions underlying Parkinson’s etiology, and promise hopes to battle against this overwhelming health danger to our aging population.
Statement of Benefit to California: 
Parkinson's disease (PD), one of the most common neurodegenerative diseases, afflicts millions of people worldwide with tremendous global economic and societal burdens. About 500,000 people are currently living with PD in the U.S, and approximate 1/10 of them live in California. The number continues to soar as our population continues to age. An effective treatment is desperately needed but the underlying molecular and cellular mechanisms of PD’s destructive path remain poorly understood. This proposal aims to explore an innovative and critical cellular mechanism that controls mitochondrial transport and clearance via mitophagy in PD pathogenesis with elegant employment of bold and creative approaches to live image mitochondria in iPSC (inducible pluripotent stem cells)-derived dopaminergic neurons from Parkinson’s patients. This study is closely relevant to public health of the state of California and will greatly benefit its citizens, as it will illuminate the pathological causes of PD and provide novel targets for therapuetic intervention.

A drug-screening platform for autism spectrum disorders using human astrocytes

Funding Type: 
Early Translational IV
Grant Number: 
TR4-06747
ICOC Funds Committed: 
$1 824 719
Disease Focus: 
Autism
Neurological Disorders
Rett's Syndrome
Pediatrics
Stem Cell Use: 
iPS Cell
oldStatus: 
Active
Public Abstract: 
Autism spectrum disorders (ASD) are complex neurodevelopmental diseases that affect about 1% of children in the United States. Such diseases are mainly characterized by deficits in verbal communication, impaired social interaction, and limited and repetitive interests and behavior. The causes and best treatments remain uncertain. One of the major impediments to ASD research is the lack of relevant human disease models. Reprogramming of somatic cells to a pluripotent state (induced pluripotent stem cells, iPSCs) has been accomplished using human cells. Isogenic pluripotent cells are attractive from the prospective to understanding complex diseases, such as ASD. The main goal of this project is to accelerate drug discovery to treat ASD using astrocytes generated from human iPSC. The model recapitulates early stages of ASD and represents a promising cellular tool for drug screening, diagnosis and personalized treatment. By testing whether drugs have differential effects in iPSC-derived astrocytes, we can begin to unravel how genetic variation in ASD dictates responses to different drugs. Insights that emerge from our studies may drive the development of new therapeutic interventions for ASD. They may also illuminate possible differences in drug responsiveness in different patients and potentially define a molecular signature resulting from ASD variants, which could predict the onset of disease before symptoms are seen.
Statement of Benefit to California: 
Autism spectrum disorders, including Rett syndrome, Angelman syndrome, Timothy syndrome, Fragile X syndrome, Tuberous sclerosis, Asperger syndrome or childhood disintegrative disorder, affect many Californian children. In the absence of a functionally effective cure or early diagnostic tool, the cost of caring for patients with such pediatric diseases is high, in addition to a major personal and family impact since childhood. The strikingly high prevalence of ASD, dramatically increasing over the past years, has led to the emotional view that ASD can be traced to a single source, such as vaccine, preservatives or other environmental factors. Such perspective has a negative impact on science and society in general. Our major goal is to develop a drug-screening platform to rescue deficiencies showed from brain cells derived from induced pluripotent stem cells generated from patients with ASD. If successful, our model will bring novel insights on the dentification of potential diagnostics for early detection of ASD risk, or ability to predict severity of particular symptoms. In addition, the development of this type of pharmacological therapeutic approach in California will serve as an important proof of principle and stimulate the formation of businesses that seek to develop these types of therapies (providing banks of inducible pluripotent stem cells) in California with consequent economic benefit.

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

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

Stem Cell Pathologies in Parkinson’s disease as a key to Regenerative Strategies

Funding Type: 
Research Leadership 10
Grant Number: 
LA1_C10-06535
ICOC Funds Committed: 
$6 718 471
Disease Focus: 
Parkinson's Disease
Neurological Disorders
oldStatus: 
Closed
Public Abstract: 
Protection and cell repair strategies for neurodegenerative diseases such as Parkinson’s Disease (“PD”) depend on well-characterized candidate human stem cells that are robust and show promise for generating the neurons of interest following stimulation of inherent brain stem cells or after cell transplantation. These stem cells must also be expandable in the culture dish without unwanted growth and differentiation into cancer cells, they must survive the transplantation process or, if endogenous brain stem cells are stimulated, they should insinuate themselves in established brain networks and hopefully ameliorate the disease course. The studies proposed for the CIRM Research Leadership Award have three major components that will help better understand the importance and uses of stem cells for the treatment of PD, and at the same time get a better insight into their role in disease repair and causation. First, we will characterize adult human neural stem cells from control and PD brain specimens to distinguish their genetic signatures and physiological properties of these cells. This will allow us to determine if there are stem cells that are pathological and fail in their supportive role in repairing the nervous system. Next, we will investigate a completely novel disease initiation and propagation mechanism, based on the concept that secreted vesicles from cells (also known as “exosomes”) containing a PD-associated protein, alpha-synuclein, propagate from cell-to cell. Our hypothesis is that these exosomes carry toxic forms of alpha-synuclein from cell to cell in the brain, thereby accounting disease spread. They may do the same with cells transplanted in patients with PD, thereby causing these newly transplanted cells designed to cure the disease, to be affected by the same process that causes the disease itself. This is a bottleneck that needs to be overcome for neurotransplantation to take its place as a standard treatment for PD. Our studies will address disease-associated toxicity of exosomal transmission of aggregated proteins in human neural precursor stem cells. Importantly, exosomes in spinal fluid or other peripheral tissues such as blood might represent a potentially early and reliable disease biomarker as well as a new target for molecular therapies aimed at blocking transcellular transmission of PD-associated molecules. Finally, we have chosen pre-clinical models with α-synucleinopathies to test human neural precursor stem cells as cell replacement donors for PD as well as interrogate, for the first time, their potential susceptibility to PD and contribution to disease transmission. These studies will provide a new standard of analysis of human neural precursor cells at risk for and contributing to pathology (so-called “stem cell pathologies”) in PD and other neurodegenerative diseases via transmission of altered or toxic proteins from one cell to another.
Statement of Benefit to California: 
According to the National Institute of Health, Parkinson’s disease (PD) is the second most common neurodegenerative disease in California and the United States (one in 100 people over 60 is affected) second only to Alzheimer’s Disease. Millions of Americans are challenged by PD, and according to the Parkinson’s Action Network, every 9 minutes a new case of PD is diagnosed. The cause of the majority of idiopathic PD is unknown. Identified genetic factors are responsible for less than 5% of cases and environmental factors such as pesticides and industrial toxins have been repeatedly linked to the disease. However, the vast majority of PD is thought to be etiologically multi-factorial, resulting from both genetic and environmental risk factors. Important events leading to PD probably occur in early or mid adult life. According to the Michael J. Fox Foundation, “…there is no objective test, or reliable biomarker for PD, so rate of misdiagnosis is high, and there is a seriously pressing need to develop better early detection approaches to be able to attempt disease-halting protocols at a non-symptomatic, so-called prodromal stage.” The proposed innovative and transformative research program will have a major direct impact for patients who live in California and suffer from PD and other related neurodegenerative diseases. If these high-risk high-pay-off studies are deemed successful, this new program will have tackled major culprits in the PD field. They could lead to a better understanding of the role of stem cells in health and disease. Furthermore they could greatly advance our knowledge of how the disease spreads throughout the brain which in turn could lead to entire new strategies to halt disease progression. In a similar manner these studies could lead to ways to prevent the disease from spreading to cells that have been transplanted to the brain of Parkinson’s patients in an attempt to cure their disease. This is critical for neurotransplantation to thrive as a therapeutic approach to treating PD. In addition, if we extend the cell-to-cell transmissible disease hypothesis to other neurodegenerative diseases, and cancer, the studies proposed here represent a new diagnostic approach and therapeutic targets for many diseases affecting Californians and humankind in general. This CIRM Research Leadership Award will not only have an enormous impact on understanding the cause of PD and developing new therapeutic strategies using stem cells and its technologies, this award will also be the foundation of creating a new Center for Translational Stem Cell Research within California. This could lead to further growth at the academic level and for the biotechnology industry, particularly in the area regenerative medicine.

The CIRM Human Pluripotent Stem Cell Biorepository – A Resource for Safe Storage and Distribution of High Quality iPSCs

Funding Type: 
hPSC Repository
Grant Number: 
IR1-06600
ICOC Funds Committed: 
$9 999 834
Disease Focus: 
Developmental Disorders
Heart Disease
Infectious Disease
Alzheimer's Disease
Neurological Disorders
Autism
Respiratory Disorders
Vision Loss
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Active
Public Abstract: 
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.
Statement of Benefit to California: 
The generation of induced pluripotent stem cells (iPSCs) from patients and subsequently, the ability to differentiate these iPSCs into disease-relevant cell types holds great promise in facilitating the “disease-in-a-dish” approach for studying our understanding of the pathological mechanisms of human disease. iPSCs have already proven to be a useful model for several monogenic diseases such as Parkinson’s, Fragile X Syndrome, Schizophrenia, Spinal Muscular Atrophy, and inherited metabolic diseases such as 1-antitrypsin deficiency, familial hypercholesterolemia, and glycogen storage disease. In addition, the differentiated cells obtained from iPSCs represent a renewable, disease-relevant cell model for high-throughput drug screening and toxicology/safety assessment which will ultimately lead to the successful development of new therapeutic agents. iPSCs also hold great hope for advancing the use of live cells as therapies for correcting the physiological manifestations caused by disease or injury.

Stem Cell Mechanisms Governing Discrete Waves of Gliogenesis in the Childhood Brain

Funding Type: 
Basic Biology IV
Grant Number: 
RB4-06093
ICOC Funds Committed: 
$1 264 248
Disease Focus: 
Neurological Disorders
Pediatrics
Stem Cell Use: 
Adult Stem Cell
oldStatus: 
Active
Public Abstract: 
White matter is the infrastructure of the brain, providing conduits for communication between neural regions. White matter continues to mature from birth until early adulthood, particularly in regions of brain critical for higher cognitive functions. However, the precise timing of white matter maturation in the various neural circuits is not well described, and the mechanisms controlling white matter developmental/maturation are poorly understood. White matter is conceptually like wires and their insulating sheath is a substance called myelin. It is clear that neural stem and precursor cells contribute significantly to white matter maturation by forming the cells that generate myelin. In the proposed experiments, we will map the precise timing of myelination in the human brain and changes in the populations of neural precursor cells that generate myelin from birth to adulthood and define mechanisms that govern the process of white matter maturation. The resulting findings about how white matter develops may provide insights for white matter regeneration to aid in therapy for diseases such as cerebral palsy, multiple sclerosis and chemotherapy-induced cognitive dysfunction.
Statement of Benefit to California: 
Diseases of white matter account for significant neurological morbidity in both children and adults in California. Understanding the cellular and molecular mechanisms that govern white matter development the may unlock clues to the regenerative potential of endogeneous stem and precursor cells in the childhood and adult brain. Although the brain continues robust white matter development throughout childhood, adolescence and young adulthood, relatively little is known about the mechanisms that orchestrate proliferation, differentiation and functional maturation of neural stem and precursor cells to generate myelin-forming oligodendrocytes during postnatal brain development. In the present proposal, we will define how white matter precursor cell populations vary with age throughout the brain and determine if and how neuronal activity instructs neural stem and precursor cell contributions to human white matter myelin maturation. Disruption of white matter myelination is implicated in a range of neurological diseases, including cerebral palsy, multiple sclerosis, cognitive dysfunction from chemotherapy exposure, attention deficit and hyperactivity disorder (ADHD) and even psychiatric diseases such as schizophrenia. The results of these studies have the potential to elucidate clues to white matter regeneration that may benefit hundreds of thousands of Californians.
Progress Report: 
  • Formation of the insulated fiber infrastructure of the human brain (called "myelin") depends upon the function of a precursor cell type called "oligodendrocyte precursor cells (OPC)". The first Aim of this study seeks to determine how OPCs differ from each other in different regions of the brain, and over different ages. Understanding this heterogeneity is important as we explore the regenerative capacity of this class of precursor cells. We have, in the past year, isolated OPCs from various regions of the human brain from individuals at various ages and are studying the molecular characteristics of these precursor cells at the single cell level in order to define distinct OPC subpopulations. We have also begun to study the functional capabilities of OPCs isolated from different brain regions. The second Aim of this study seeks to understand how interactions between electrically active neurons and OPCs affect OPC function and myelin formation. We have found that when mouse motor cortex neurons "fire" signals in such a way as to elicit a complex motor behavior, much as would happen when one practices a motor task, OPCs within that circuit respond and myelination increases. This affects the function of that circuit in a lasting way. These results indicate that neurons and OPCs interact in important ways to modulate myelination and supports the hypothesis that OPC function may play a role in learning.

Modeling disease in human embryonic stem cells using new genetic tools

Funding Type: 
Basic Biology IV
Grant Number: 
RB4-05855
ICOC Funds Committed: 
$1 387 800
Disease Focus: 
Neuropathy
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 
The use of stem cells or stem cell-derived cells to treat disease is one important goal of stem cell research. A second, important use for stem cells is the creation of cellular models of human development and disease, critical for uncovering the molecular roots of illness and testing new drugs. However, a major limitation in achieving these goals is the difficulty in manipulating human stem cells. Existing means of generating genetically modified stem cells are not ideal, as they do not preserve the normal gene regulation, are inefficient, and do not permit removal of foreign genes. We have developed a method of genetically modifying mouse embryonic stem cells that is more efficient than traditional methods. We are adapting this approach for use with human embryonic stem cells, so that these cells can be better understood and harnessed for modeling, or even treating, human diseases. We will use this approach to create a human stem cell model of Charcot-Marie-Tooth (CMT) disease, an inherited neuropathy. How gene dysfunction leads to nerve defects in CMT is not clear, and there is no cure or specific therapy for this neurological disease. Thus, we will use our genetic tools to investigate how gene function is disrupted to cause CMT. By developing these tools and using them to gain understanding of CMT, we will illustrate how this system can be used to gain insight into other important diseases.
Statement of Benefit to California: 
Although human stem cells hold the potential to generate new understanding about human biology and new approaches to important diseases, the inability to efficiently and specifically modify stem cells currently limits the pace of research. Also, there is presently no safe means of changing genes compatible with the use of the stem cells in therapies. We are developing new genetic tools to allow for the tractable manipulation of human stem cells. By accelerating diverse other stem cell research projects, these tools will enhance the scientific and economic development of California. We will use these tools to create cellular models of Charcot-Marie-Tooth (CMT), a neurological disease with no cure that affects about 15,000 Californians. This model will facilitate understanding of the etiology of CMT, and may lead to insights that can be used to develop specific therapies. Beyond gaining insight into CMT, the ability to engineer specific genetic changes in human stem cells will be useful for many applications, including the creation of replacement cells for personalized therapies, reporter lines for stem cell-based drug screens, and models of other diseases. Thus, our research will assist the endeavors of the stem cell community in both the public and private arenas, contributing to economic growth and new product development. This project will also train students and postdoctoral scholars in human stem cell biology, who will contribute to the economic capacity of California.
Progress Report: 
  • An important use for stem cells is the creation of cellular models of human development and disease, critical for uncovering the molecular roots of illness and testing new drugs. However, a major limitation in achieving these goals is the difficulty in manipulating human stem cells. We have developed a method of genetically modifying mouse embryonic stem cells that is more efficient than traditional methods. During the first year of this project, we adapted this approach for use with human embryonic stem cells. We have also created gene trap mutations in a diversity of human embryonic stem cell genes that can be used to better harness human embryonic stem cells for modeling, or even treating, human diseases.

Stem cell models to analyze the role of mutated C9ORF72 in neurodegeneration

Funding Type: 
Basic Biology IV
Grant Number: 
RB4-06045
ICOC Funds Committed: 
$1 393 200
Disease Focus: 
Amyotrophic Lateral Sclerosis
Neurological Disorders
Dementia
Neurological Disorders
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Active
Public Abstract: 
Amyotrophic lateral sclerosis (ALS) is an idiopathic adult-onset degenerative disease characterized by progressive weakness from loss of upper and lower motor neurons. Onset is insidious, progression is essentially linear, and death occurs within 3-5 years in 90% of patients. In the US, 5,000 deaths occur per year and in the world, 100,000. In October, 2011, the causative gene defect in a long sought after locus on chromosome 9 for ALS, frontotemporal dementia (FTD) and overlap ALS-FTD was identified to be a expansion of a hexanucleotide repeat in the uncharacterized C9ORF72 gene. The goal of the proposed research is to generate human stem cell models from cells derived from ALS patients with the C9ORF72 expanded repeats and relevant control cells using genome-editing technology. We will also generate a stem cell model expressing the repeat independent of the C9ORF72 gene to study if the repeat alone is causing neural defects. Using advanced genome technologies, biochemical and cellular approaches, we will study the molecular pathways affected in motor neurons derived from these stem cell models. Finally, we will use innovative technologies to rescue the abnormal phenotypes that arise from the expanded repeat in human motor neurons. Completion of the proposed research is expected to transform our understanding of the regulatory and pathogenetic mechanisms underlying ALS and FTD, and establish therapeutic options for these debilitating diseases.
Statement of Benefit to California: 
Our research provides the foundation for decoding the mechanisms that underlie the single most frequent genetic mutation found to contribute to both ALS and FTD, debilitating neurological diseases that impact many Californians. In California, the expected prevalence of ALS (the number of total existing cases) is 2,200 to 3,000 cases at any one time, and the incidence is 750-1,100 new cases each year. The number of FTD cases is five times as many. Our research has and will continue to serve as a basis for understanding deviations from normal and disease patient neuronal cells, enabling us to make inroards to understanding neurological disease modeling using neurons differentiated from reprogammed patient-specific lines. Such disease modeling will have great potential for California health care patients, pharmaceutical and biotechnology industries in terms of improved human models for drug discovery and toxicology testing. Our improved knowledge base will support our efforts as well as other Californian researchers to study stem cell models of neurological disease and design new diagnostics and treatments, thereby maintaining California's position as a leader in clinical research.
Progress Report: 
  • Expanded hexanucleotide repeats in the C9ORF72 gene were identified in Oct 2011 as a cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), thus identifying the single most frequent genetic cause of each and connecting them to repeat expansion disease. We are developing stem cell disease models to enable key hypotheses of pathogenesis and new interventions to be tested. We have successfully engineered stem cell models to analyze the effects of C9ORF72 mutations, and have differentiated these stem cell models into motor neurons which enabled us to conduct transcriptomic and biochemical studies. In addition, we have utilized antisense-oligonucleotides (ASOs) from ISIS Pharmaceuticals to deplete mutant C9ORF72 in motor neurons. We expect our efforts to provide mechanistic insights and a potential therapy in human cells.

Mechanism and Utility of Direct Neuronal Conversion with a MicroRNA-Chromatin Switch

Funding Type: 
Basic Biology IV
Grant Number: 
RB4-05886
ICOC Funds Committed: 
$1 392 426
Disease Focus: 
Neurological Disorders
Stem Cell Use: 
Directly Reprogrammed Cell
oldStatus: 
Active
Public Abstract: 
Many human diseases and injuries that affect the brain and nervous system could potentially be treated by either introducing healthy neurons or persuading the cells that normally provide supporting functions to become functioning neurons. A number of barriers must be traversed to bring these goals to practical therapies. Recently our laboratory and others have found ways of converting different human cell types to functioning neurons. Surprisingly, two routes for the production of neurons have been discovered. Our preliminary evidence indicates that these two routes are likely to work together and therefore more effective ways of producing neurons can likely be provided by understanding these two routes, which is one aim of this application. Another barrier to effective treatment of human neurologic diseases has been the inability to develop good models of human neurologic disease due to inability to sample tissues from patients with these diseases. Hence we will understand ways of making neurons from blood cells and other cells, which can be easily obtained from patients with little or no risk. Our third goal will be to understand how different types of neurons can be produced from patient cells. We would also like to understand the barriers and check points that keep one type of cell from becoming another another type of cell. Understanding these mysterious processes could help provide new sources of human cells for replacement therapies and disease models.
Statement of Benefit to California: 
The state of California and its citizens are likely to benefit from the work described in this proposal by the development of more accurate models for the testing of drugs and new means of treatment of human neurologic diseases. Presently these diseases are among the most common afflicting Californians, as well as others and will become more common in an aging population. Common and devastating diseases such as Alzheimer’s, Schizophrenia, Parkinson's Disease, and others lack facile cell culture models that allow one to probe the basis of the disease and to test therapies safely and without risk to the patient. Our work is already providing these models, but we hope to make even better ones by understanding the fundamental processes that allow one cell type (such as a skin cell or blood cell) to be converted to human neurons, where the disease process can be investigated. In the past the inability to make neurons from patients with specific diseases has been a major roadblock to treatment. In the future the studies described here might be able to provide healthy neurons to replace ones loss through disease or injury.
Progress Report: 
  • During the past year, our laboratory has investigated the way that human skin cells can be changed to neurons. To do this, we have used a natural switch that occurs as embryonic cells decide to become neurons. We have found that this process proceeds in a highly ordered series of stages that involve first a resetting of fundamental cell biologic processes characteristic of neurons. This is followed by activation of genes encoding proteins that allow different types of neurons to interact and develop communication between one another. This finding surprised us since we expected to find changes in transcription factors, which instruct the formation of neurons. Instead, we find that the natural switching mechanism in neurons first regulates cell-to-cell communication.

Role of the NMD RNA Decay Pathway in Maintaining the Stem-Like State

Funding Type: 
Basic Biology IV
Grant Number: 
RB4-06345
ICOC Funds Committed: 
$1 360 450
Disease Focus: 
Neurological Disorders
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Active
Public Abstract: 
A subset of intellectual disability cases in humans are caused by mutations in an X-linked gene essential for a quality control mechanism called nonsense-mediated RNA decay (NMD). Patients with mutations in this gene—UPF3B—commonly have not only ID, but also schizophrenia, autism, and attention-deficit/hyperactivity disorder. Thus, the study of UPF3B and NMD may provide insight into a wide spectrum of cognitive and psychological disorders. To examine how mutations in UPF3B can cause mental defects, we will generate and characterize induced-pluripotent stem cells from intellectual disability patients with mutations in the UPF3B gene. In addition to having a role in neural development, our recent evidence suggests that NMD is important for maintaining the identity of ES cells and progenitor cells. How does NMD do this? While NMD is a quality control mechanism, it is also a well characterized biochemical pathway that serves to rapidly degrade specific subsets of normal messenger ribonucleic acids (mRNAs), the transiently produced copies of our genetic material: deoxyribonucleic acid (DNA). We have obtained evidence that NMD preferentially degrades mRNAs that interfere with the stem cell program (i.e., NMD promotes the decay mRNAs encoding proteins that promote differentiation and inhibit cell proliferation). In this proposal, we will identify the target mRNAs of NMD in stem and progenitor cells and directly address the role of NMD in maintaining the stem-like state.
Statement of Benefit to California: 
iPS cells provide a means to elucidate the mechanisms underlying diseases that afflict a growing number of Californians. Our proposed project concerns making and testing iPS cells from patients with mutations in the UPF3B gene, all of whom have intellectual disabilities. In addition, many of these patients have autism, attention-deficit disorders, and schizophrenia. By using iPS cells to identify the cellular and molecular defects in these patients, we have the potential to ultimately ameliorate the symptoms of many of these patients. This is important, as over 1.6 million people in California have serious mental illness. Moreover, a large proportion of patients with UPF3B mutations have autism, a disorder that has undergone an alarming 12-fold increase in California between 1987 and 2007. The public mental health facilities in California are inadequate to meet the needs of people with mental health disorders. Furthermore, what is provided is expensive: $4.4 billion was spent on public mental health agency services in California in 2006. Mental health problems also exert a heavy burden on California’s criminal justice system. In 2006, over 11,000 children and 40,000 adults with mental health disorders were incarcerated in California’s juvenile justice system. Our research is also directed towards understanding fundamental mechanisms by which all stem cells are maintained, which has the potential to also impact non-psychiatric disorders suffered by Californians.
Progress Report: 
  • A key quality of stem cells is their ability to switch from a proliferative cell state in which they reproduce themselves to a differentiated cell state that ultimately allows them to carry out the functions of a fully mature cell. Most research on the nature of this switch has focused on the role of proteins that determine whether the genetic material—DNA—generates a copy of it itself in the form of messenger RNA, a process called transcription. In stem cells, such proteins—which are called transcription factors—activate the production of messenger RNAs encoding proteins that promote the proliferative and undifferentiated cell state. They also increase the production of messenger mRNAs that encode inhibitors of differentiation and cell proliferation. The level and profile of such transcription factors are altered in response to signals that trigger stem cells to differentiate. For example, transcription factors that promote the undifferentiated cell state are decreased in level and transcription factors that drive differentiation down a particular lineage are increased in level. While this transcription factor-centric view of stem cells explains some aspects of stem cell biology, it is, in of itself, insufficient to explain many of their behaviors, including both their ability to maintain the stem-like state and to differentiate. We hypothesize that a molecular pathway that complements transcription-base mechanisms in controlling stem cell maintenance vs. differentiation decisions is an RNA decay pathway called nonsense-mediated RNA decay (NMD). Messenger RNA decay is as important as transcription in determining the level of messenger RNA. Signals that trigger increased decay of a given messenger RNA leads to decreased levels of its encoded protein, while signals that trigger the opposite response increase the level of the encoded protein. Our project revolves around two main ideas. First, that NMD promotes the stem-like state by preferentially degrading messenger RNAs that encode differentiation-promoting proteins and proliferation inhibitor proteins. Second, that NMD must be downregulated in magnitude to allow stem cells to differentiate. During the progress period, we obtained substantial evidence for both of these hypotheses. With regard to the first hypothesis, we have used genome-wide approaches to identify hundreds of messenger RNAs that are regulated by NMD in both in vivo (in mice) and in vitro (in cell lines). To determine which of these messenger mRNAs are directly degraded by NMD, we have used a variety of approaches. This work has revealed that NMD preferentially degrades messenger RNAs encoding neural differentiation inhibitors and proliferation inhibitors in neural stem cells. In contrast, very few messenger RNAs encoding pro-stem cell proteins or pro-proliferation proteins are degraded by NMD. Together this provides support for our hypothesis that NMD promotes the stem-like state by shifting the proportion of messenger RNAs in a cell towards promoting an undifferentiated, proliferative cell state. With regard to the second hypothesis, we have found that many proteins that are directly involved in the NMD pathway are downregulated upon differentiation of stem and progenitor cells. Not only are NMD proteins reduced in level, but we find that the magnitude of NMD itself is reduced. We have used a variety of molecular techniques to determine whether this NMD downregulatory response has a role in neural differentiation and found that NMD downreglation is both necessary and sufficient for this event. Such experiments have also revealed particular messenger mRNAs degraded by NMD that are crucial for the NMD downregulatory response to promote neural differentiation. Our research has implications for intellectual disability cases in humans caused by mutations in an X-linked gene essential for NMD. Patients with mutations in this gene—UPF3B—not only have intellectual disability, but also schizophrenia, autism, and attention-deficit/hyperactivity disorder. Thus, the study of NMD may provide insight into a wide spectrum of cognitive and psychological disorders. We are currently in the process of generating induced-pluripotent stem (iPS) cells from intellectual disability patients with mutations in the UPF3B gene towards this goal.

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