Contactin-2 protects against aortic valve calcification via osteogenic differentiation inhibition

Current pharmacological strategies for delaying the progression of calcific aortic valve disease (CAVD) remain inadequate. This study used Mendelian randomization (MR) analysis to identify a significant association between the plasma protein Contactin-2 (CNTN2) and CAVD. Transcriptomic and in vivo/in vitro experiments further validated these findings. An MR study was conducted to evaluate the exposure-outcome relationship between plasma proteins and CAVD. Transcriptomic profiling identified differentially expressed genes and also analyzed pathways related to the osteogenic differentiation phenotype of human primary aortic valve interstitial cells (hVICs), which further validated the MR analysis. Western blotting, Alizarin Red staining and immunohistochemistry were used to validate the MR result in hVICs and patients with CAVD. Furthermore, adenovirus-mediated CNTN2 overexpression in hVICs was performed to elucidate the role in the osteogenic phenotype. MR analysis demonstrated a significant causal association between CNTN2 and CAVD. Colocalization analysis indicated that CNTN2 shares genetic loci with CAVD. Gene Ontology (GO) analyses revealed that CNTN2 was downregulated in hVICs with an osteogenic phenotype. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that CNTN2 is enriched in pathways associated with the osteogenic phenotype. Immunoblotting further confirmed that CNTN2 protein expression was reduced in osteogenically induced hVICs and in clinical specimens obtained from patients with CAVD. Additionally, overexpression of CNTN2 significantly inhibited the osteogenic phenotype of hVICs. CNTN2 has a significant causal relationship with CAVD and contributes to protection during aortic valve calcification. These findings could provide new insights and therapeutic targets for the prevention and treatment of CAVD.