MAFA S64F Missense Mutation Causes Islet Beta-Cell Aging and Senescence

A missense mutation of the pancreatic islet-enriched transcription factor MAFA (S64F) was identified in patients characterized by familial diabetes or insulinomatosis, with males more prone to diabetes. This variant converts the normally unstable MAFA protein to be unusually stable. A heterozygous germline mouse model expressing this variant (S64F MafA Het) mimics the sex-dependent phenotype in humans: Het males have impaired glucose tolerance while Het females have hypoglycemia. Het males also showed increased MafA protein stability preceding glucose intolerance (Figure 1) and upregulation of genes involved in aging/senescence (Figure 2). These results implicate accelerated aging/senescence in islet β-cell dysfunction in males with the S64F MAFA mutation. Future studies will evaluate the broader significance of these processes in diabetes. Disclosure J. Cha: None. E.M. Walker: None. X. Tong: None. M. Guo: None. J. Liu: None. S. Yu: None. D. Iacovazzo: None. F. Mauvais-Jarvis: None. S.E. Flanagan: None. M. Korbonits: None. J.M. Stafford: None. R. Stein: None. Funding National Institutes of Health (T32DK007061, F32DK109577, R01DK090570); JDRF (3-PDF-2019-738-A-NDK109577)