Deciphering Rho-associated, coiled-coil-containing protein kinase in diabetic nephropathy: small steps towards a giant leap.

Diabetic nephropathy is a public health problem worldwide. Our understanding of the molecular machinery, as well as the clinical therapies for diabetic nephropathy, has evolved dramatically in recent years. However, even with this progress, there are residual risks of kidney failure and cardiovascular events in patients with diabetes. Rho-associated, coiled-coil-containing protein kinase (ROCK) is activated in response to various pathologic stimuli in the context of diabetes. The contribution of ROCK has been investigated in vivo using gene deletion rodent models and specific inhibitors, which are providing key insights into the pathologic function of ROCK in diabetic nephropathy. ROCK has two isoforms, ROCK1 and ROCK2. Both isoforms are expressed in the kidney, including mesangial cells, podocytes, and endothelial cells. ROCK1 blunts AMP-activated protein kinase (AMPK), while ROCK2 negatively regulates peroxisome proliferator-activated receptor α (PPARα) to inhibit fatty acid oxidation, both of which lead to structural and functional impairment of glomeruli in diabetes. Of note, ROCK signaling is activated in the kidney of animal models and patients with diabetes. In addition, an observational study has shown that fasudil hydrochloride, an ATP-competitive selective ROCK inhibitor, significantly attenuated proteinuria among patients with diabetes. These findings highlight the promising prospects for the development of a ROCK-centered approach against the progression of diabetic nephropathy.