Vascular oxidative stress and
inflammation play a major role in
vascular diseases. This study was aimed at determining the protective roles of fibronectin type III domain-containing 5 (FNDC5) in
angiotensin II- (Ang II-) induced vascular oxidative stress and
inflammation and underlying mechanisms. Wild-type (WT) and FNDC5-/- mice, primary mouse vascular smooth muscle cells (VSMCs), and the rat aortic smooth muscle cell line (A7R5) were used in the present study.
Subcutaneous infusion of Ang II caused more serious
hypertension,
vascular remodeling, oxidative stress, NLRP3
inflammasome activation, AMPK phosphorylation inhibition, and
SIRT1 downregulation in the aorta of FNDC5-/- mice than those of WT mice. Exogenous FNDC5 attenuated Ang II-induced
superoxide generation,
NADPH oxidase 2 (NOX2) and NLRP3 upregulation, mature caspase-1, and interleukin-1β (IL-1β) production in A7R5 cells. The protective roles of FNDC5 were prevented by SIRT-1 inhibitor EX527,
AMPK inhibitor compound C, or
integrin receptor inhibitor
GLPG0187. FNDC5 attenuated the Ang II-induced inhibition in
SIRT1 activity,
SIRT1 protein expression, and AMPKα phosphorylation in A7R5 cells, which were prevented by compound C, EX527, and
GLPG0187. FNDC5 deficiency deteriorated Ang II-induced oxidative stress, NLRP3
inflammasome activation, AMPK phosphorylation inhibition, and
SIRT1 downregulation in primary aortic VSMCs of mice, which were prevented by exogenous FNDC5. These results indicate that FNDC5 deficiency aggravates while exogenous FNDC5 alleviates the Ang II-induced vascular oxidative stress and NLRP3
inflammasome activation via the AMPK-SIRT1 signal pathway in VSMCs.