Mechanisms of matrix stiffness affecting calcific aortic valve disease by regulating Piezo1

Mechanical factors have been found to trigger and promote calcific aortic valve disease (CAVD). Extracellular matrix (ECM) stiffness, one of the main mechanical factors, plays an important role in valve calcification. However, the specific mechanisms underlying ECM stiffness during CAVD progression remain unclear and require further investigation.

Atomic force microscopy was used to analyze the Young's modulus of the human aortic valves. Western blotting was performed to detect the COL4A3, COL1A1, ALP, RUNX2, and Piezo1 protein levels in valvular interstitial cells (VICs) cultured on a soft matrix. After Piezo1 was silenced in vitro, we evaluated ECM remodeling and osteogenic differentiation of VICs. We established an aortic valve calcification model in LDLR^-/- mice by a high-fat/cholesterol diet and evaluated the effect of AAV2-sh-Piezo1 on CAVD. RNA-seq was used to explore the mechanism by which Piezo1 affects CAVD.

The Young's modulus of human calcified aortic valves was higher than that of normal aortic valves. Increased matrix stiffness upregulated Piezo1 and promoted ECM remodeling and osteogenic differentiation of VICs. In vitro, silencing of Piezo1 decreased COL4A3 expression and prevented the osteogenic differentiation of VICs. In vivo, Piezo1 knockdown ameliorated mouse aortic valve ECM remodeling and calcification. We found that Piezo1 may influence the Wnt pathway.

A Piezo1-mediated feedback loop may interconnect ECM stiffening, VIC osteogenic differentiation, and pathological ECM remodeling during CAVD progression.