Basic Biology V
Recommended if funds allow
Autism and autism spectrum disorders (ASD) are complex neurodevelopmental diseases that affect 1 in 88 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. One of the major impediments to ASD research is the lack of relevant human disease models. ASD animal models are limited and cannot reproduce the important language and social behavior impairment of ASD patients. 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. Development and maintenance of neuronal circuits requires a complex series of events involving coordinated communication between multiple cell types over multiple length scales of space and time. The possibility that exosomes, a type of extracellular membrane vesicles, function as a novel type of cell-cell communication to establish and maintain neuronal circuits have not been explored. We propose to test the hypothesis that exosome-mediated signaling is deficient in ASD. We have established a human ASD prototype model, with clear and robust differences. We anticipate gaining insights into the causal molecular mechanisms of ASD and to discover potential biomarkers and novel specific therapeutic targets.
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 a novel hypothesis based on our preliminary data, suggesting that a new type of cell-cell communication may impact neurons derived from induced pluripotent stem cells generated from patients with ASD. If successful, our model will bring novel insights on the identification 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 diagnostic approach in California will serve as an important proof of principle and stimulate the formation of businesses that seek to develop early ASD detection tools in California with consequent economic benefit, and maintaining California's position as a leader in stem cell research.
Development and maintenance of neuronal circuits requires a complex series of events involving coordinated communication between many cell types in the central nervous system (CNS). The possibility that exosomes, a type of extracellular membrane vesicle, function as a novel type of cell-cell communication to establish and maintain neuronal circuits have not been explored. The investigators propose to test the hypothesis that exosome-mediated signaling is deficient in a specific human neurodevelopmental disorder prototype model used in this study. The proposal aims to study exosomes as a possible novel signaling unit between neural cells. This fundamental track application proposes to tackle this gap in our knowledge, using patient-derived induced pluripotent stem cells (iPSCs). The hypothesis to be tested is that exosomes serve as a form of communication for development and function of neural circuitry and that they are deficient in disease-derived iPSCs. Experimental aims include identifying the protein and RNA content of exosomes from control and the disease prototype-derived iPSC lines. In addition, the studies aim to determine if exosomes from neurons/glia of control individuals can rescue the disease prototype-derived neurons. Significance and Innovation - The proposal is significant since it targets a novel potential mechanism for exosome-mediated neural communication, which might provide mechanistic insights into neurodevelopmental related pathologies. - The studies may be limited in their applicability to clinical syndromes since they are performed strictly in vitro with cell culture techniques. There were some concerns regarding the potential of gene-mediated reactivation. - The hypothesis is innovative, the rationale is logical and the proposed aims appear systematic and achievable. All the necessary support facilities are available to the investigators to complete the proposed studies. - The application explores a novel question, and a fundamental question about the ways in which neural cells interact and form networks. Feasibility and Experimental Design - Reviewers were concerned that the use of in vitro neuronal cultures might not have the same exosomal content and characteristics as the in vivo counterparts in normal and diseased conditions. - The application appears to be based on sound preliminary evidence as parts of the proposal are already published. However, reviewers raised concerns whether the right cells will be used for this study since the neural differentiation protocol won’t result in upper cortical neurons. - Most of the proposed experiments appear feasible, although some concern was expressed regarding the ability to accomplish the validation of cargo candidates since limited preliminary data was presented in support of the proposed experiments. Principal Investigator (PI) and Research Team - The PI and the collaborators have a strong track record. The collaborators in this grant have the appropriate expertise to cover any deficiencies or concerns regarding the technical skills of the team. Responsiveness to the RFA - The proposal is in line with the goals and objectives of the RFA.