Vascular Endothelial ROCK2 Deficiency Promotes Browning and Burning of White Adipose Tissue

The accumulation of visceral fat is associated with multiple coronary risk factors such as glucose intolerance, dyslipidemia, and hypertension. We have previously demonstrated that Rho/Rho-associated protein kinase (ROCK) signaling is activated in animal models of diabetes and is involved in the pathogenesis of vascular complications. Specifically, ROCK is implicated in the molecular basis of inflammation- and ischemia-induced tissue damage through the actions on NF-κB dynamics. These findings support the hypothesis that ROCK signaling could be one of the important therapeutic targets for preventing cardiorenal events. However, isoform-specific roles of ROCKs have not been clarified yet. In this study, we aimed to determine the tissue-intrinsic roles of ROCK2 in the setting of obesity. To this end, we generated vascular endothelium-specific ROCK2 knockout mice (ER2KO) by crossing ROCK2 floxed mice with VE-Cadherin-Cre mice. ER2KO mice were fertile and had the same lifespan as wild type mice. Notably, ER2KO gained weight at a slower rate than wild type mice under high-fat diet feeding. Fat composition, as assessed by magnetic resonance imaging, was significantly lower in ER2KO, even though ER2KO displayed increased food intake. The gene expression analysis revealed increased expression of PPARα, a browning-inducing factor, and its downstream components, CIDEA, IL-4, and IL-10, in white adipose tissue obtained from ER2KO mice. ER2KO mice also showed an elevation in body temperature after fasting, suggesting that endothelial ROCK2 may negatively regulate fat browning. In summary, vascular endothelial ROCK2 negatively regulates fat accumulation through the mechanism of browning inhibition. Disclosure Y. Takeda: None. K. Matoba: None. R. Ukichi: None. Y. Nagai: None. Y. Kanazawa: None. K. Utsunomiya: None. R. Nishimura: Speaker's Bureau; Abbott Diabetes, Astellas Pharma Inc., AstraZeneca, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Medtronic, Merck & Co., Inc., Novo Nordisk, Ono Pharmaceutical Co., Ltd., Sanofi, Taisho Pharmaceutical Holdings Co., Ltd., Takeda Pharmaceutical Company Limited, Teijin Pharma Limited, Terumo Corporation. Funding a Grant-in-Aid for Scientific Research from Japan Society for the Promotion of Science, the MSD Life Science Foundation, the Takeda Science Foundation, the Suzuken Memorial Foundation, Sanofi KK, Tanabe Pharma, and Takeda Pharmaceutical., Kazunori Utsunomiya has received research support from Terumo, Novo Nordisk Pharma, Taisho Pharmaceutical, Böehringer Ingelheim, Kyowa Hakko Kirin, Sumitomo Dainippon Pharma, and OPharmaceutical as, Rimei Nishimura has received speaker honoraria from Astellas Pharma, Nippon Boehringer Ingelheim, Eli Lilly Japan KK, Kissei Pharmaceutical, Medtronic Japan, MSD, Novartis Pharma KK, Novo Nordisk Phar.