Participation of the AngII/TRPC6/NFAT axis in the pathogenesis of podocyte injury in rats with type 2 diabetes.

The canonical transient receptor potential channel 6 ion channel is expressed in podocytes and is an important component of the glomerular slit diaphragm. Focal segmental glomerulosclerosis is closely associated with TRPC6 gene mutations, and TRPC6 mediates podocyte injury induced by high glucose. Angiotensin II (AngII) has been revealed to enhance TRPC6 currents in certain types of cells, including podocytes and ventricular myocytes. It has been reported that glucose regulated TRPC6 expression in an AngII‑dependent manner in podocytes and that this pathway is critical in diabetic nephropathy. In the present study, the role of TRPC6 detected by western blotting and reverse transcription‑quantitative polymerase chain reaction in AngII‑mediated podocyte injury was evaluated in rats with type 2 diabetes induced by high‑calorie diets and streptozotocin. The results demonstrated that urinary albumin excretion was elevated, and morphological changes, including glomerular basement membrane thickening and podocyte process effacement, were observed. There was increased expression of AngII and TRPC6 in diabetic rats. The angiotensin receptor blocker valsartan significantly reduced TRPC6 and nuclear factor of activated T‑cells (NFAT) overexpression in diabetic rats. These results in vivo were confirmed by studies in vitro, which demonstrated that inhibition of TRPC6 ameliorated high glucose‑induced podocyte injury by decreasing NFAT mRNA levels. Taken together, the present results suggested that the AngII/TRPC6/NFAT axis may be a crucial signaling pathway in podocytes that is necessary for maintaining the integrity of the glomerular filtration barrier. In addition, TRPC6 may represent a potential therapeutic target for diabetic nephropathy.