Harnessing Novel Human Endocrine Progenitor Biology for Enhanced Generation of Beta Cells from Stem Cells

About This Grant

The long-term objectives of this project are to elucidate the mechanisms underlying human endocrine lineage commitment and harness this knowledge to improve strategies for beta cell replacement in diabetes treatment. Diabetes is one of the fastest growing health emergencies worldwide, affecting hundreds of millions of individuals. Type 1 diabetes (T1D) is a disease of the endocrine pancreas characterized by lack of glucose homeostasis due to immune-mediated destruction of insulin-producing beta cells. Beta cell replacement therapy holds great promise for eliminating the need for exogenous insulin delivery and effectively curing the disease. Understanding the mechanisms underlying endocrine cell fate and function will be crucial for continued progress towards realizing the goals of both cell replacement therapy and beta cell regeneration. Although several protocols have been devised to generate insulin-secreting beta-like cells from human pluripotent stem cells (hPSCs), these protocols suffer from the production of non- endocrine cell types and a failure to match the transcriptional profiles and glucose responsiveness of native adult human islets. This may be because current protocols are based on knowledge of rodent development and may therefore be missing key regulatory pathways and lineage steps unique to human development. Indeed, multiple studies have identified discrepancies between mouse and human pancreatic islets, including structural, transcriptomic, and metabolic differences. Therefore, gaining a deeper understanding of human endocrine development is crucial for continued progress towards generating in vitro-derived beta cells that recapitulate endogenous function. Our laboratory has recently made a set of fundamental discoveries regarding endocrine progenitors (EPs) in human. We utilized single-cell multi-omics to generate a comprehensive atlas of developing pancreas, identified four novel EP states unique to human, and revealed divergent lineage relationships in human tissue versus mouse. We have identified a novel cell population, marked by the transcription factor FEV, that represents a fate-restricted EP population that gives rise to human beta cells. Our work now provides a critical new lens through which to examine human endocrine lineage commitment, and to apply this knowledge to improve beta cell differentiation from hPSCs. Our goal is to elucidate the mechanisms underlying human endocrine lineage commitment and harness this knowledge to improve strategies for beta cell replacement. The experiments outlined in this proposal begin with a focus on characterizing the spatial and temporal appearance of the novel EP populations that we have identified in developing human pancreas. In addition, studies will be undertaken to investigate the function of the gene FEV in the development of human beta cells using genome editing of hPSC-derived endocrine cells. Lastly, we will use a combination of strategies to isolate distinct populations of differentiating hPSC-derived beta-like cells and their progenitors to test whether off-target cells are detrimental and to refine which sub-population leads to optimal diabetic rescue.