Abstract 19279: Rescue Of D2R Function in Mouse Kidney Using AAV9 Vector Abrogates the Renal Injury and High Blood Pressure Induced by D2R Silencing
In humans decreased dopamine D2 receptor (D2R) expression and function is associated hypertension and inflammation and fibrosis in renal proximal tubule cells. In mice selective D2R silencing in the kidney results in renal inflammation, injury and hypertension. We hypothesized that these alterations are ameliorated by rescue of renal D2R function. To test this hypothesis we silenced renal D2R expression by sub-capsular infusion of D2R siRNA (D2RsiRNA) using osmotic mini pumps (3 μg/day, n=6 per group). Mice treated with non-silencing siRNA (NS siRNA) served as controls. Two weeks after starting siRNA treatment, mice were treated with control AAV (CAAV) or AAV carrying wild-type D2R (D2RAAV) (n=3 per group, 1e+11 vgp/mouse). Two weeks following AAV treatment, blood pressure was measured and organs were collected. D2R expression was decreased in D2RsiRNA-treated kidneys compared with NSsiRNA-treated kidneys (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 with silenced D2R expression (D2RsiRNA+CAAV) had increased systolic blood pressure (121±3 mmHg; P<0.05) in comparison with the D2R rescued group ( D2RsiRNA+D2RAAV) (100±6 mm Hg), NSsiRNA+CAAV (101±4 mm Hg), or NS siRNA +D2RAAV (101±1 mm Hg). D2R silencing caused an increase in the expression of TNF-α, 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 these proteins was decreased or reversed to normal in the D2R-rescued group. Masson trichrome staining showed tubular atrophy, interstitial fibrosis and extensive areas of scaring in D2R silenced mice while these abnormalities were significantly reduced in the D2R rescued group. T cells infiltration was significantly higher in D2R silenced group compared to the D2R-rescued group (309 ± 38 vs 217± 17 %; P<0.05). These results show that D2R re-expression prevented the progression of the lesions and 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. C.B. Drachenberg: None. P.A. Jose: None. I. Armando: None.
- © 2015 by American Heart Association, Inc.