FP-receptor gene silencing ameliorates myocardial fibrosis and protects from diabetic cardiomyopathy

Prostaglandin F2(alpha)-F-prostanoid (PGF2(alpha)-FP) receptor is closely related to insulin resistance, which plays a causal role in the pathogenesis of diabetic cardiomyopathy (DCM). We sought to reveal whether PGF2(alpha)-FP receptor plays an important part in modulating DCM and the mechanisms involved. We established the type 2 diabetes rat model by high-fat diet and low-dose streptozotocin (STZ) and then evaluated its characteristics by metabolite tests, Western blot analysis for FP-receptor expression, histopathologic analyses of cardiomyocyte density and fibrosis area. Next, we used gene silencing to investigate the role of FP receptor in the pathophysiologic features of DCM. Our study showed elevated cholesterol, triglyceride, glucose, and insulin levels, severe insulin resistance, and FP-receptor overexpression in diabetic rats. The collagen volume fraction (CVF) and perivascular collagen area/luminal area (PVCA/LA) were higher in the diabetic group than the control group (CVF% 10.99 +/- 0.99 vs 1.59 +/- 0.18, P < 0.05; PVCA/LA% 17.07 +/- 2.61 vs 2.86 +/- 0.69, P < 0.05). We found that the silencing of FP receptor decreased cholesterol, triglyceride, glucose, and insulin levels and ameliorated insulin resistance. The CVF and PVCF/LA were significantly downregulated in FP-receptor short hairpin RNA (shRNA) treatment group (FP-receptor shRNA group vs vehicle group: CVF% 5.59 +/- 0.92 vs 10.97 +/- 1.33, P < 0.05, PVCA/LA% 4.74 +/- 1.57 vs 14.79 +/- 2.22, P < 0.05; FP-receptor shRNA + PGF2(alpha) group vs vehicle group : CVF% 5.19 +/- 0.79 vs 10.97 +/- 1.33, P < 0.05, PVCA/LA% 5.96 +/- 1.15 vs 14.79 +/- 2.22, P < 0.05, respectively). Furthermore, with FP-receptor gene silencing, the activated protein kinase C (PKC) and Rho kinase were significantly decreased, and the blunted phosphorylation of Akt was restored. FP-receptor gene silencing may exert a protective effect on DCM by improving myocardial fibrosis, suggesting a new therapeutic approach for human DCM.