Sestrin2 Is Increased in Calcific Aortic Disease and Inhibits Osteoblastic Differentiation in Valvular Interstitial Cells via the Nuclear Factor E2–related Factor 2 Pathway

Sestrin2 (Sesn2) is involved in the progression of cardiovascular diseases, such as hypertension and myocardial infarction. This study aimed to examine Sesn2 expression in human calcific aortic valve disease (CAVD) and explore its possible mechanisms by which Sesn2 participates in this process. CAVD and normal aortic valves were collected. Sesn2 expression and sources were examined, and the results showed that Sesn2 expression was increased in aortic valves from patients with CAVD and was mainly secreted by macrophages. Additionally, U937 macrophages were pretreated with si-Sesn2 or cDNA-Sesn2 and further treated with oxidized low-density lipoprotein (ox-LDL); M1 macrophages and their markers were measured, and we found that pretreatment with si-Sesn2 increased ox-LDL–induced M1 macrophage polarization and marker mRNA levels, whereas pretreatment with cDNA-Sesn2 had the opposite effects. In ox-LDL–treated U937 macrophages, oxidative stress levels were increased in the si-Sesn2 pretreatment group and further increased by si-Nrf2 treatment, whereas oxidative stress levels were decreased in the cDNA-Sesn2 pretreatment group and significantly reversed by ML385, a specific Nrf2 inhibitor. The effects of Sesn2 on ox-LDL-induced oxidative stress and the osteogenic differentiation of ox-LDL-induced valvular interstitial cells (VICs) was examined by down-regulating Nrf2 pathway. When U937 macrophages were co-cultured with VICs, downregulation of Sesn2 increased ox-LDL-induced osteogenic differentiation in VICs, whereas overexpression of Sesn2 exerted the opposite effects. Our study suggests that Sesn2 is increased in CAVD aortic valves and may participate in the development of CAVD by regulating oxidative stress via the Nrf2 pathway.