Aberrant increases in protein phosphatase 1(PP1) activity have been shown to be associated with inefficient sarcoplasmic reticulum Ca^{2+} cycling, leading to cardiac dysfunction in the failing heart. In the present study, we investigated whether BNP promoter-inducible suppression of PP1β would ameliorate progression of pressure overload-induced heart failure in mice, a clinically relevant animal model. An Adeno-associated virus 9 (AAV9) vector encoding PP1βshRNA and a negative control (NC) shRNA driven by a brain natriuretic peptide (BNP) promoter with an emerald green fluorescent protein expression (EmGFP) cassette were used to test the hypothesis. AAV9 vectors (AAV9-BNP-EmGFP-PP1βshRNA and AAV9-BNP-EmGFP-NCshRNA) were introduced into the in vivo heart via the tail vein injection (4x10^{11} GC/mice) in 8-week-old C57BL6J mice, followed by transverse aortic constriction (TAC) 2 weeks after the AAV9 vector injection. Post TAC cardiac function was sequentially assessed every 2 week by echocardiography, followed by hemodynamic assessment at 1 month. AAV9-BNP-EmGFP-PP1βshRNA treatment suppressed myocardial PP1β expression by 15% compared with the NCshRNA group (p<0.001). The fractional shortening (%FS) of the left ventricle in the PP1βshRNA-treated group was significantly larger than the NCshRNA-treated group (21%±1.0% vs. 15%±0.01, p<0.01). The ratios of heart weight (HW) / body weight (BW) and lung weight (LW) / BW in the PP1βshRNA group were significantly smaller than those of the NCshRNA group (HW/BW: 9.20±0.49 vs. 10.6±0.45 mg/g

Background: Angiotensin II (AngII) increases reactive oxygen species (ROS) and induces glomerular sclerosis. Toll-like receptor 4 (TLR4)-mediated inflammation enhances the renal impairment in renal inflammatory diseases. The relationship between TLR4 and AngII-induced glomerular sclerosis is unknown.Methods: Mice lacking TLR4 function (Tlr4^{lps-d}) and wild-type (WT) mice were randomized into groups treated with AngII, norepinephrine (NE) or a sub-depressor dose of the AngII receptor blocker irbesartan along with AngII for 2 weeks. We then assessed the expressions of NADPH oxidase and monocyte chemoattractant protein-1 (MCP-1) and the inflammatory cell recruitment in the glomeruli. We also evaluated the mesangial matrix proliferation and ROS.Results: AngII and NE equally increased the systolic blood pressure compared to the control mice (p<0.05). In the WT mice treated with AngII, we observed glomerular sclerosis, an increase in NADPH oxidase, MCP-1 and the infiltration of macrophages as well as ROS content in the glomeruli compared to the control mice (p<0.05), whereas the Tlr4^{lps-d} mice showed little effects of AngII on these indices. In addition, the sub-depressor-dose irbesartan treatment reversed these changes. NE had little effects on these indices. Conclusions: TLR4 plays an important role in AngII-induced oxidative stress, inflammation and glomerular sclerosis through the AT1 receptor.