Investigating the Molecular Mechanisms of Beta-Cell Expansion Factor A-induced Beta-Cell Proliferation

PROJECT SUMMARY/ABSTRACT Beta-Cell Expansion Factor A (BefA) is a secreted bacterial protein that induces the proliferation of β-cells and promotes proper endocrine function during early development in both zebrafish and mice. The molecular mechanisms by which BefA induces β-cell proliferation and metabolic maturation are not known. BefA contains a structurally conserved SYLF domain that mediates interactions with phospholipids and disrupts membrane integrity. The broad and long-term objective of this project is to learn the molecular mechanisms by which BefA impacts pancreatic β-cells. This work has wide-reaching possibilities for the development of therapeutic interventions for both type I and type II diabetes through a better understanding of β-cell proliferation and metabolic maturation to aid in the production of human induced pluripotent stem cell-derived β-cells. The focus of this proposal is to investigate how BefA’s demonstrated membrane perturbing activity promotes β-cell proliferation and metabolic maturation. In Specific Aim 1, I will utilize single-cell resolution live imaging, genetic manipulation of zebrafish, and human induced pluripotent stem cells to investigate whether BefA- induced intracellular calcium signaling promotes β-cell proliferation. In Specific Aim 2, I will utilize imaging of β-cell mitochondria membrane potential and morphology and human induced pluripotent stem cell derived β- cells to test whether BefA’s impacts on mitochondria promote β–cells' metabolic maturation. If successful, the outcome of this proposal will be a new understanding of how membrane perturbation in vivo can promote proliferation, insulin secretion, and metabolic maturation of the essential insulin-producing β-cells. I aim to translate my mechanistic findings to advance the in vitro production of functional β-cells for cell therapies of type I and type II diabetes. Furthermore, the molecular insights I will discover, research protocols I will develop, and skills I will acquire through these studies will promote my development as an independent scientist, β-cell biologist, and prepare me for my future career in understanding the molecular mechanisms of microbiome impacts on host health.