Deletion of OGlcNAc Transferase in Pancreatic Progenitors Causes Partial Pancreas Agenesis and Diabetes Independent of p53 in Mice

Abstract

Deletion of the only nutrient-sensor enzyme, O-GlcNAc Transferase (OGT), catalyzing O-GlcNAc addition onto target proteins in pancreatic β-cells induces diabetes through β-cell failure. We hypothesized that OGT, expressed at a very high level in β-cells, has key developmental regulatory properties. In this study, we tested the hypothesis that OGT is required for pancreas and β-cell development by deleting OGT in pancreatic (Pdx1Cre, OGTKOPanc) or endocrine (Ngn3Cre, OGTKOEndo) progenitors. We show that mice lacking OGT in pancreatic progenitors (Pdx1+, OGTKOPanc) show near pancreas agenesis and loss of β-cell mass at birth. Few mice that grow into adulthood develop overt diabetes due to functional β-cell mass failure. OGT ablation in endocrine progenitors (Ngn3+, OGTKOEndo) resulted in normal pancreas mass but reduced β-cell mass and diabetes early in life, strongly revealing the temporal and importance of OGT for β-cell development. We observed loss of Pdx1 staining at birth and on embryonic (e) day 14.5 in OGTKOPanc. Transcriptome analysis of e14.5 progenitor single cells show distinct cell clustering populations in OGTKOPanc compared to littermate controls. Upstream regulator analysis of altered genes show enhanced activation of p53, also known as TP53 or tumor protein. Next we identified p53 to be O-GlcNAc-modified in β-cells. Concomitant deletion of p53 in the OGTKOPanc background (p53,OGTKOPanc) does not rescue pancreas agenesis in OGTKOPanc newborn, and adult p53,OGTKOPanc mice develop severe hyperglycemia and diabetes. These data highlight the novel role O-GlcNAc-modifications in pancreas and β-cell development and provide a new model to characterize the developmental defects associated with pancreatic agenesis. Disclosure E. Alejandro: None. D. Baumann: None. S. Jo: None. B. Akhaphong: None. A.D. Lockridge: None. R. Mohan: None.