Abstract 16236: Rescue of D2R Function in Mouse Kidney Using AAV9 Vector Abrogates the Renal Injury and High Blood Pressure Induced by D2R Silencing
The renal dopaminergic system plays a key role in salt homoeostasis and blood pressure regulation. Lack or down regulation of dopamine D2 receptor (D2R) function in mice increases the vulnerability to renal inflammation and high blood pressure. We hypothesized that rescuing renal D2R expression in mice in which D2R is silenced in the kidney will reduce renal inflammation, injury and normalize the blood pressure. Gene transfer studies showed that retrograde ureteral infusion of AAV9 vectors encoding firefly luciferase or eGFP provide heterologous gene expression in the collecting duct, distal convoluted tubule, and proximal tubule cells of the infused kidney. D2R expression was silenced by the renal sub-capsular infusion of D2R siRNA (D2RsiRNA) using osmotic mini pump (3 μg/day, n=6 per group). Mice treated with non-silencing siRNA (NS siRNA) served as controls. Fourteen days following the initiation of siRNA treatment, each group was treated with control AAV (CAAV) or AAV carrying wild-type D2R (D2RAAV) (n=3 per group, 1e+11 vgp/mouse). Fourteen days following AAV treatment, arterial blood pressure was measured and organs were collected. D2R expression was decreased in D2RsiRNA-treated kidneys compared with NS siRNA-treated kidneys (immunoblotting: 54 ± 0.8 vs 100± 22 %; P<0.05). D2RAAV treatment increased D2R expression (7.5-11-fold; P<0.01) in both D2RsiRNA and NS siRNA-treated mice. Mice treated with D2RsiRNA+CAAV had increased systolic blood pressure (121±3 mmHg; P<0.05) in comparison with the mice treated with D2RsiRNA+D2RAAV (100±6 mm Hg) (rescued mice), NS siRNA +CAAV (101±4 mm Hg), or NS siRNA +D2RAAV (101±1 mm Hg). D2R silencing (D2RsiRNA+CAAV) caused an increase in the expression of pro-inflammatory TNF-α, the pro-fibrotic TGF-β1 and its downstream target fibronectin-1, as well as kidney injury molecule-1 and ki-67, a marker of cell proliferation. By contrast, the expression of the same proteins was reversed to normal in the D2R-rescued group (D2RsiRNA+D2RAAV). In conclusion, these results demonstrate that increased blood pressure and renal injury due to D2R silencing could be rescued by over expression of D2R in the kidney using AAV9 vector. Furthermore, these data provide the basis for designing novel therapies for kidney disease.
Author Disclosures: P. Konkalmatt: None. L.D. Asico: None. Y. Yang: None. P.A. Jose: None. I. Armando: None.
- © 2014 by American Heart Association, Inc.