Knockdown of estrogen-related receptor α inhibits valve interstitial cell calcification in vitro by regulating heme oxygenase 1

Calcific aortic valve disease (CAVD) is the most common valvular heart disease in adults. The cellular mechanisms of CAVD are still unknown, but accumulating evidence has revealed that osteogenic differentiation of human valve interstitial cells (hVICs) plays an important role in CAVD. Thus, we aimed to investigate the function of estrogen-related receptor alpha (ERR alpha) in the osteogenic differentiation of hVICs. We found that the level of ERR alpha was significantly increased in CAVD samples compared to normal controls. In addition, ERR alpha was significantly upregulated during hVIC osteogenic differentiation in vitro. Gain- and loss-of-function experiments were performed to identify the function of ERR alpha in hVIC calcification in vitro. Inhibition of endogenous ERR alpha attenuated hVIC calcification, whereas overexpression of ERR alpha in hVICs promoted this process. RNA sequencing results suggested that heme oxygenase-1 (Hmox1) was a downstream target of ERR alpha, which was further confirmed by western blotting. Additionally, we also found that downregulation of Hmox1 by shHmox1 efficiently reversed the inhibition of calcification induced by ERR alpha shRNA in hVICs. ChIP-qPCR and luciferase assays indicated that Hmox1 was negatively regulated by ERR alpha. We found that overexpression of Hmox1 or its substrates significantly inhibited hVIC calcification in vitro. In conclusion, we found that knockdown of ERR alpha can inhibit hVIC calcification through upregulating Hmox1 and that ERR alpha and Hmox1 are potential targets for the treatment of CAVD.

Automated summary

This study reveals that ERRα plays a crucial role in CAVD by regulating the expression of Hmox1 which affects the calcification process of hVICs. ERRα and Hmox1 may be potential targets for the treatment of CAVD.