The Endoplasmic Reticulum Stress Protein Calreticulin in Diabetic Chronic Kidney Disease

We hypothesize that ER stress induced by glucose in diabetes promotes diabetic CKD through CRT stimulation of TGF-beta-dependent calciumNFAT signaling in renal proximal tubule cells. In Aim 1 we will determine the role of CRT in mediating the fibrogenic effects of TGF-beta and glucose in renal cells. In Aim 2, we will determine the role of CRT in mouse models of diabetic nephropathy. In year 2, we developed stably transduced HK-2 cells using lentivirus to enable us to perform long term studies in culture. Importantly, we performed animal studies this year, which showed that ultrasound mediated delivery of cre-recombinase plasmid to CRT floxed mice reduces CRT expression by 30-40 with primary down regulation in the tubules which persisted over 5 months. Down regulation of CRT expression in diabetic CRT floxed mice showed a significant reduction in the urinary albumincreatinine ratio, indicating attenuation of renal dysfunction, and improved survival. We also saw reduced fibrosis by electron microscopy and PAS staining and by western blot for fibronectin.