Dipeptidyl peptidase-4 plays a pathogenic role in BSA-induced kidney injury in diabetic mice.

Diabetic kidney disease (DKD) is appeared to be higher risk of declining kidney function compared to non-diabetic kidney disease with same magnitude of albuminuria. Epithelial-mesenchymal transition (EMT) program of tubular epithelial cells (TECs) could be important for the production of the extracellular matrix in the kidney. Caveolin-1 (CAV1), dipeptidyl peptidase-4 (DPP-4) and integrin β1 have shown to be involved in EMT program. Here, we found diabetic kidney is prone for albuminuria-induced TECs damage and DPP-4 plays a vital role in such parenchymal damages in diabetic mice. The bovine serum albumin (BSA) injection induced severe TECs damage and altered expression levels of DPP-4, integrin β1, CAV1, and EMT programs including relevant microRNAs in type 1 diabetic CD-1 mice when compared to non-diabetic mice; teneligliptin (TENE) ameliorated these alterations. TENE suppressed the close proximity among DPP-4, integrin β1 and CAV1 in a culture of HK-2 cells. These findings suggest that DPP-4 inhibition can be relevant for combating proteinuric DKD by targeting the EMT program induced by the crosstalk among DPP-4, integrin β1 and CAV1.