Rac1 mediates cadherin-11 induced cellular pathogenic processes in aortic valve calcification

• Published in: Cardiovascular pathology 2022-05, Vol.58, p.107414-107414, Article 107414
• Main Authors: Vaidya, Kiran A., Donnelly, Matthew P., Mahmut, Ablajan, Jang, Jae Woong, Gee, Terence W., Aibo, Marine-Ayan Ibrahim, Bossong, Robert, Hall, Clare, Samb, Sanjay, Chen, Jonathan, Butcher, Jonathan T.
• Format: Article
• Language: English
• Subjects: Animals; Aortic Valve - pathology; Aortic valve calcification; Aortic Valve Stenosis - pathology; Cadherin; Cadherins; Calcinosis - etiology; Cells, Cultured; Mice; Rac1; Swine
• ISSN: 1054-8807; 1879-1336; 1879-1336
• DOI: 10.1016/j.carpath.2022.107414

•Rac1 is highly upregulated in calcified human aortic valve leaflets•Rac1 is highly colocalized with Cad11 in calcified human aortic valve leaflets•Rac1 mediates Cad11-induced aortic valve pathogenic processes•Rac1 itself promotes downstream cell migration, compaction, and calcification•The Rac1 inhibitor, NSC23766, prevents Cad11-induced calcification : Calcific aortic valve disease (CAVD), a major cause for surgical aortic valve replacement, currently lacks available pharmacological treatments. Cadherin-11 (Cad11), a promising therapeutic target, promotes aortic valve calcification in vivo, but direct Cad11 inhibition in clinical trials has been unsuccessful. Targeting of downstream Cad11 effectors instead may be clinically useful; however, the downstream effectors that mediate Cad11-induced aortic valve cellular pathogenesis have not been investigated. : Immunofluorescence of calcified human aortic valves revealed that GTP-Rac1 is highly upregulated in calcified leaflets and is 2.15 times more co-localized with Cad11 in calcified valves than GTP-RhoA. Using dominant negative mutants in porcine aortic valve interstitial cells (PAVICs), we show that Cad11 predominantly regulates Runx2 nuclear localization via Rac1. Rac1-GEF inhibition via NSC23766 effectively reduces calcification in ex vivo porcine aortic valve leaflets treated with osteogenic media by 2.8-fold and also prevents Cad11-induced cell migration, compaction, and calcification in PAVICs. GTP-Rac1 and Trio, a known Cad11 binding partner and Rac1-GEF, are significantly upregulated in Nfatc1Cre; R26-Cad11Tg/Tg (Cad11 OX) mice that conditionally overexpress Cad11 in the heart valves by 3.1-fold and 6.3-fold, respectively. Finally, we found that the Trio-specific Rac1-GEF inhibitor, ITX3, effectively prevents Cad11-induced calcification and Runx2 induction in osteogenic conditions. : Here we show that Cad11 induces many cellular pathogenic processes via Rac1 and that Rac1 inhibition effectively prevents many Cad11-induced aortic disease phenotypes. These findings highlight the therapeutic potential of blocking Rac1-GEFs in CAVD. Graphical Abstract [Display omitted] .