Abstract 16799: Galectin-1 Alleviates Aortic Valve Calcification via Modulating Integrin-Mediated Cytoskeletal Reorganization and Focal Adhesion

Abstract

Background Galectin-1, a beta-glycoside binding protein, has been reported to involve a variety of cell functions including proliferation, cell migration and focal adhesion. The role of cell-matrix interaction in calcific aortic valve disease (CAVD) is not fully investigated and whether galectin-1 is involved in this process remains unclear. We hypothesized that galectin-1 mitigates the fibrocalcific response and mechanosensitivity of valve interstitial cells (AVICs) by modulating integrin-mediated cytoskeletal reorganization and focal adhesion. Methods and Results We enrolled patients with CAVD and age- and sex-matched controls to detect serum galectin-1 and found that circulating galectin-1 was lower in CAVD. The expression of galectin-1 decreased in fibrocalcific valves and AVICs cultured in osteogenic medium (OM), as shown by western blot, qPCR, immunohistochemistry (IHC) and immunofluorescence. Silencing galectin-1 by short-interfering RNA exacerbated the fibrocalcific change of AVICs in vitro while recombinant galectin-1 (rGal-1) prevented these effects. AVICs cultured in OM also presented enhanced integrin signaling, cytoskeletal reorganization and focal adhesion. Anti-integrin blocking experiments and co-immunoprecipitation assays demonstrated that the galectin-1 directly interacted with integrin αvβ1 to regulate AVICs adhesion to a fibronectin matrix. Western blot, qPCR and Immunofluorescence assays confirmed that actin cytoskeletal reorganization was induced by αvβ1 activation through Rac1-WRC-Arp2/3 signaling axis. Western blot, alkaline phosphatase (ALP) as well as Alizarin red staining demonstrated that silencing galectin-1 enhanced AVICs sensitivity to piezo1 activation, which is dependent on αvβ1 binding and actin polymerization. In vivo, aortic valve disease was constructed by direct wire injury (DWI), and we showed that overexpression of galectin-1 by adeno-associated virus significantly decelerated the progression of aortic valve lesion induced by DWI in mice. Conclusion Galectin-1 interacts with integrin αvβ1 to modulate cytoskeletal reorganization and AVICs adhesion to fibronectin, thus mitigating the fibrocalcific response of AVICs and aortic valve calcification.