Upregulation of FGF13 promotes type 2 diabetic nephropathy by modulating glomerular endothelial mitochondrial homeostasis

Studies of diabetic glomerular injury raise the possibility of developing useful early biomarkers and therapeutic approaches for the treatment of type 2 diabetic nephropathy (T2DN). In this study, it is found that FGF13 expression is induced in glomerular endothelial cells (GECs) during T2DN progression, and endothelial-specific deletion of Fgf13 potentially alleviates T2DN damage. Fgf13 deficiency restores the expression of Parkin both in the cytosolic, mitochondrial, and nuclear fractions under diabetic conditions, resulting in improved mitochondrial homeostasis and endothelial barrier integrity due to promotion of mitophagy and inhibition of apoptosis. Additionally, it is confirmed that the beneficial effects of Fgf13 deficiency on T2DN are abolished by endothelial-specific double deletion of Fgf13 and Prkn. The effects of Fgf13 deficiency on mitophagy and apoptosis via Parkin-dependent regulation may be distinct and separable events under diabetic conditions. These data show that the bifunctional role of Fgf13 deficiency in promoting mitophagy and inhibiting apoptosis through Parkin can shape mitochondrial homeostasis regulation in GECs and T2DN progression. Acting as a potential biomarker and therapeutic target for prevention and control of T2DN, mechanistically understanding of the biofunction of FGF13 may also be of relevance to the pathogenesis of other FGF13- and Parkin-associated diseases.