Abstract P197: Vacuolar-type H + -ATPase Enhances Renal (Pro)renin Expression and Inflammation in Response to High Glucose

Abstract

(Pro)renin receptor (PRR) is an accessory subunit for vacuolar-type H-ATPase (V-ATPase). Recently, we demonstrated that PRR expression is upregulated in diabetes and promotes renal inflammation. We hypothesized that V-ATPase enhances renal PRR expression and inflammation in response to high glucose. Rat renal mesangial cells (RMCs) were cultured for 3 days in medium containing 25 mM D-glucose (high glucose) for experiments groups and 5 mM D-glucose plus 20 mM L-glucose (normal glucose) for control group. Cells were serum starved for 6 hrs at the end of the 3 day glucose exposure, thereafter 100nM bafilomycin, a V-ATPase inhibitor, treatment was given for 1 hour. At the end of experiments, cells were harvested for total RNA and protein for the determination of PRR and interleukin-6 (IL-6). High glucose significantly (P<0.05) increased mRNA and protein expression of PRR (Fig 1) by 87 (1 vs 1.87) and 52% (1 vs 1.52) respectively, and IL-6 level (Fig 2) by 44% (1 vs 1.44, P<0.05), when compared to their respective normal glucose cells. Bafilomycin treatment attenuated the increase in mRNA and protein expression of PRR by 74 (1.87 vs 0.47, P<0.05) and 45% (1.52 vs 0.83, P<0.05). Similarly, IL-6 mRNA level was also lower by 62% (1.44 vs 0.54, P<0.05) in bafilomycin treated high glucose cells compared to its non-treated counterpart. The present study conclude that V-ATPase contributes to increased renal PRR expression and inflammation in presence of hyperglycemia.