Pitavastatin suppresses hyperglycaemia-induced podocyte injury via bone morphogenetic protein-7 preservation

Podocytes form the essential components of the glomerular filtration barrier and play a critical role in diabetic nephropathy. Recent evidence suggests that HMG-CoA reductase inhibitors (statins) exert renoprotective effects. We investigated whether pitavastatin directly suppresses hyperglycaemia-induced podocyte injury using cultured podocytes and, if so, the mechanism of the beneficial effects. Cultured podocytes were exposed to media containing normal (NG; 5 mmol/L) or high (HG; 25 mmol/L) glucose for 1 week. HG increased the lethal injury of podocytes and disruption of F-actin fibers, and reduced the mRNA expression of novel podocyte markers, synaptopodin and Wilms tumor-1 (WT-1), in association with decreased bone morphogenetic protein-7 (BMP-7) expression. Pitavastatin (100 nmol/L) reduced podocyte injury and restored the mRNA expression of synaptopodin and WT1; however, these protective effects were abolished by BMP-7 siRNA. Additionally, pitavastatin suppressed HG-induced Rho kinase activation, as assessed by the phosphorylation level of myosin phosphatase targeting subunit 1 (MYTP1), and C3 exotoxin, a Rho inhibitor, mimicked the effect of pitavastatin on BMP-7 preservation. Pitavastatin attenuates hyperglycaemia-induced podocyte injury via Rho-Rho kinase-dependent BMP-7 preservation.