MAFA and type 2 diabetes mellitus: In addition, T2DM C57BL/6J mice fed with HFD upregulated proteins involved in pancreatic β-cell proliferation and downregulation of glutathione peroxidase gene (Gpx1) implicated in the antioxidant defenses of β-cells and in the regulation of MafA expression, which is important in the regulation of insulin expression [161].