Cytoskeletal regulation of gut tube organogenesis and subsequent maturation of stem cell-derived islets

About This Grant

PROJECT SUMMARY This proposal for a K01 Mentored Career Development Award details a Career Development Training Plan and Research Strategy to facilitate the candidate’s transition to an independent investigator role in diabetes research. In particular, the candidate’s long-term research goal is to make impactful discoveries that will enable a cell-based therapy to become a viable and widely-used treatment option for type 1 diabetes (T1D), alleviating the hardships and complications associated with this disease. To guide the candidate’s transition to independence, the Career Development Training Plan integrates a scientific research proposal investigating new aspects of β cell development and maturation, a mentoring team of experts in stem cell and β cell biology, and the world-class research environment at Washington University in St. Louis. T1D results from the selective autoimmune destruction of the insulin-producing β cells in pancreatic islets. Studies have shown that transplanting human cadaveric pancreatic islets into T1D patients reduces or eliminates the need for exogenous insulin injections, indicating that replacing the destroyed β cells can serve as a functional cure for insulin-dependent diabetes. However, issues with human donor islet supply, quality, and immunogenicity have limited the widespread use of this approach. In an effort to generate an unlimited supply of highly functional islets for cell therapy, excellent progress has been made in the generation of stem cell-derived islets (SC-islets) via direct differentiation protocols. In particular, these cells are able to replicate the first and second phase insulin secretion kinetics of primary β cells, the ability to cure severely diabetic mice within two weeks of transplantation, and further maturation after long-term transplantation. Despite these remarkable advancements, current generation SC-islets still lag behind primary human islets in terms of insulin secretion and overall islet composition. Emerging evidence has demonstrated that microenvironmental cues (e.g., substrate composition and mechanical properties) sensed by cells through their actin cytoskeleton play important signaling roles in cell behavior and fate selection in several model systems, but actin’s role in the directed differentiation of hPSCs to endodermal cell types has been very limited. To further enhance the specification to and maturation of SC- islets using these principles, this proposal seeks to leverage microenvironmental cues transduced through the actin cytoskeleton and its downstream pathways to improve pancreatic specification during gut tube organogenesis as well as during endocrine cell maturation. These studies aim to improve specification to pancreatic β cells, eliminate other undesired cell types (e.g., enterochromaffin cells), as well as enhance the functional maturation and identity of these β cells. Successful completion of these objectives will not only improve the clinical effectiveness of SC-islets but will also uncover fundamental insights into the biology of how cytoskeletal state influences endodermal cell development.