26-OR: Genome-Scale CRISPR Screen Identifies ALDH3B2 Loss-of Function Transdifferentiates Human Pancreatic Duct Cells Into Beta-Like Cells

Introduction and Objective: Pancreatic beta cell trans-differentiation is a phenomenon whereby new beta cells are generated from other pancreatic progenitor cells. It has been believed that pancreatic duct cells serve as a pool for the islet after birth or adulthood. Nevertheless, uncertainties persist regarding the regulation of beta cell trans-differentiation and whether it can be induced with sufficient efficiency to restore functional beta cell mass for diabetes treatment. Methods: Here we employed a genome-wide CRISPR screen (Figure 1B) to dissect the mechanism of human beta cell trans-differentiation and to identify new therapeutic targets (ALDH3B2) for beta cell mass restoration by induction of trans-differentiation. To execute the CRISPR screen, as illustrated in Figure 1A. Results: Our study demonstrates that loss-of-function mutations in ALDH3B2 can induce trans-differentiation of human primary pancreatic duct cells (HPPD) into beta-like cells. HPPD cells with ALDH3B2 mutations show responsiveness to glucose challenges in vivo. Single-cell RNA sequencing of control and ALDH3B2 mutant HPPD cells revealed that 18.1% of the mutant cells express insulin, compared to 0.6% in control cells. Importantly, around 93% of all cells maintained the duct cell marker KRT19 expression. Conclusion: Results suggest that a single gene, ALDH3B2, in pancreatic duct cells is sufficient to promote a beta-like cell phenotype. Disclosure J. Li: None.