3116-LB: Wnt5a-Mediated Disruption of Lysosomal Function Drives ß-Cell Dysfunction in Type 2 Diabetes Mellitus

Introduction and Objective: β-cell dysfunction drives progression of type 2 diabetes (T2DM), yet mechanisms linking metabolic stress to impaired β-cell homeostasis remain unclear. Lysosomes regulate insulin granule turnover, autophagy, and cell survival. We examined whether Wnt5a modulates lysosomal function in β-cells during T2DM progression. Methods: An S961-induced insulin resistance model was used to assess temporal changes in Wnt5a and lysosomal genes. β-cell-specific Wnt5a knockout mice (Ins1Cre; Wnt5afx/fx) were evaluated after S961 treatment. Lysosomal abundance was analyzed by electron microscopy. β-cells were exposed to high glucose (30 mM) with or without Wnt5a inhibition to assess lysosomal markers and autophagic flux. TFEB nuclear localization was examined. For therapeutic studies, AAV-RIP-shWnt5a was delivered via pancreatic duct injection in high-fat diet-induced insulin- Results: Wnt5a was markedly upregulated at late-stage S961 treatment, coinciding with reduced lysosomal gene expression. Wnt5a deletion significantly improved β-cell function after S961 exposure. Knockout β-cells exhibited increased lysosomal abundance. High glucose reduced Cathepsin D and LAMP1 expression, whereas Wnt5a inhibition restored their levels and reduced p62 accumulation, indicating enhanced autophagic flux. Recombinant Wnt5a suppressed TFEB nuclear translocation. In vivo, AAV-mediated Wnt5a knockdown improved glucose tolerance, restored TFEB nuclear localization, and increased lysosomal gene expression. Conclusion: Wnt5a promotes β-cell dysfunction in T2DM by suppressing TFEB-dependent lysosomal biogenesis and autophagy. Targeting the Wnt5a-TFEB axis may preserve β-cell function during diabetes progression. Disclosure Y. Jiang: None.