Abstract 023: Inducible Deletion of Adipocyte Prorenin Receptor Reverses Obesity Related Hypertension

Abstract

Obesity contributes to approximatively 2.5 million deaths every year and is associated with life threatening conditions including hypertension. Recently, we found that constitutive deletion of adipocyte (pro)renin-receptor (PRR) prevented high-fat diet-induced obesity through a drastic decrease in fat mass. However, adipocyte PRR deficient mice were characterized by a fatty liver and by an elevated systolic blood pressure (SBP), classic features of models of lipodystrophy. The purpose of this study was to investigate whether the temporally-controlled deletion of adipocyte PRR in obese mice reverses obesity related hypertension. After 18 weeks of high fat diet, inducible adipocyte-PRR deficient ( PRR ERT ) and control ( PRR fl/Y ) male mice (n=7-11 mice/ group) were injected intraperitoneally with tamoxifen (TMX) for 5 consecutive days. Body weight, body composition and blood pressure, measured by radiotelemetry in a subgroup of mice (n=2-4 mice/ group), were recorded before and after TMX injection. The inducible deletion of adipocyte PRR in PRR ERT mice decreased significantly body weights ( PRR fl/fl , 46.6 ± 1.3 g; PRR ERT , 42.1 ± 1.4 g, P<0.05) and fat mass ( PRR fl/fl , 15.8 ± 1.0 g; PRR ERT , 8.1 ± 0.7 g, P<0.05) compared to control mice. PPARγ, FABP4 and FAS mRNA levels were significantly decreased by 68% (6.8 out 10), 80% (8 out 10) and 68% (6.8 out 10) respectively in white adipose tissues of PRR ERT mice suggesting that PRR positively regulated adipogenesis and lipid metabolism in adipose tissue. In addition, the inducible deletion of adipocyte PRR in PRR ERT mice decreased significantly SBP compared to control mice ( PRR fl/fl , -4.3 ± 3.2 g; PRR ERT , -10.2 ± 2.4 g, P<0.05). Interestingly, adipocyte angiotensinogen mRNA abundance was significantly decreased in adipose tissue of PRR ERT mice fed a standard diet suggesting that the decrease in blood pressure might be mediated by a local renin angiotensin system (RAS). The measurement of local (liver, kidney, adipose tissue and brain) and systemic RAS in HF-fed mice is under investigation. Taken together, our results highlight a new signaling pathway in which PRR regulates adipogenesis, lipid metabolism and blood pressure. PRR could represent a new potential therapeutic target for obesity and hypertension.