Making a better beta cell for cellular therapeutics of diabetes

About This Grant

Diabetes is a tremendous healthcare burden, with costs of hundreds of billions a year in the US. Diabetes has 2 major forms, type 1 diabetes (T1D) and type 2 diabetes (T2D). While these diseases have distinct causes (immune dysfunction or metabolic dysfunction), end stage disease in both leads to loss of beta cell mass and glucose homeostasis. Protocols have been developed to generate beta-like cells from human pluripotent stem cells (PSC)s which are currently in clinical trials as a cellular therapy for T1D and T2D. A beta cell therapeutic faces several hurdles to become a long-term cure for diabetes. First, it must survive transplantation which includes a hypoxic environment prior to graft vascularization and survive the inflammatory environment induced by the transplant surgery. For long term survival, the graft needs to be robust and survive diabetic conditions before the graft achieves full functionality and for use in T2D patients, needs to be able to function and overcome insulin resistance by secreting sufficient insulin long term. Lastly, immune attack of the graft by the host immune system needs to be prevented. Immune attack is being addressed by many groups in the scientific community via multiple strategies. This proposal is focused on generating the most robust stem cell derived beta cell that can survive and function long term in challenging conditions present in diabetic patients. To do so, we are leveraging naturally occurring hyperactive mutations that have been found in the HNF1A gene and which protect individuals from T2D. HNF1A is a transcription factor important in beta cell development and function. Loss of function mutations in HNF1A is the most common cause of monogenic diabetes and genome wide association studies have linked this gene to both T1D and T2D. Multiple studies of loss of function HNF1A mutants have demonstrated defects in insulin secretion, glycolysis, mitochondria function, and response to cellular stress. We hypothesize that the HNF1A hyperactive mutants will have superior function and response to cellular stress. We will test this hypothesis by generating a panel of hyperactive HNF1A mutants previously found in the human population in human PSCs. These mutants will be tested both in vitro and in vivo utilizing rodent xenotransplant studies. A second focus of this proposal is to acquire a deeper understanding of the mechanisms in how HNF1A loss of function can influence diabetes pathogenesis. HNF1A can influence both beta cell development but also plays a role directly in beta cell function. To focus on its role in beta cells, we are utilizing genetically engineered human PSC lines where HNF1A can be degraded specifically after development into beta cells. We will use this system to study how acute loss of HNF1A impacts beta cell function, survival, and response to cellular stressors important in diabetes pathogenesis. This proposal will give new insights into beta cell function and responses to cell stress which is critical for diabetes pathogenesis and developing cellular therapies for this disorder.