Peroxisome Proliferator-Activated Receptor α Attenuates Hypertensive Vascular Remodeling by Protecting Vascular Smooth Muscle Cells from Angiotensin II-Induced ROS Production

Vascular remodeling is the fundamental basis for hypertensive disease, in which vascular smooth muscle cell (VSMC) dysfunction plays an essential role. Previous studies suggest that the activation of peroxisome proliferator-activated receptor alpha (PPAR alpha) by fibrate drugs has cardiovascular benefits independent of the lipid-lowering effects. However, the underlying mechanism remains incompletely understood. This study explored the role of PPAR alpha in angiotensin II (Ang II)-induced vascular remodeling and hypertension using VSMC-specific Ppara-deficient mice. The PPAR alpha expression was markedly downregulated in the VSMCs upon Ang II treatment. A PPAR alpha deficiency in the VSMC significantly aggravated the Ang II-induced hypertension and vascular stiffness, with little influence on the cardiac function. The morphological analyses demonstrated that VSMC-specific Ppara-deficient mice exhibited an aggravated vascular remodeling and oxidative stress. In vitro, a PPAR alpha deficiency dramatically increased the production of mitochondrial reactive oxidative species (ROS) in Ang II-treated primary VSMCs. Finally, the PPAR alpha activation by Wy14643 improved the Ang II-induced ROS production and vascular remodeling in a VSMC PPAR alpha-dependent manner. Taken together, these data suggest that PPAR alpha plays a critical protective role in Ang II-induced hypertension via attenuating ROS production in VSMCs, thus providing a potential therapeutic target for hypertensive diseases.