AIF1 and diabetes mellitus: Consistent with milder STZ-induced diabetic phenotypes of Nptnf/f; Ins1Cre mice, staining area of panmacrophage marker, IBA1, was reduced in pancreatic sections of Nptnf/f; Ins1Cre mice injected with STZ (Fig. 4I), indicating that NPTN contributes to islet inflammation and the development of insulitis and diabetes.