Identification of mitochondria-related genes in calcific aortic valve disease by integrated analysis of single-cell and bulk transcriptomic atlases

Calcific aortic valve disease (CAVD) is a highly prevalent heart valve disorder in which mitochondria act as critical regulators of calcification, yet their precise pathogenic mechanisms remain unclear. To elucidate these mechanisms, we integrated single-cell transcriptomic datasets comparing normal and calcified human aortic valves to identify 200 differentially expressed mitochondria-related genes (DE-MRGs), each exhibiting distinct expression patterns across diverse cellular subpopulations. Pseudotime trajectory analysis revealed 18 DE-MRGs with dynamic changes during the endothelial-to-mesenchymal transition, and intercellular communication analysis highlighted enhanced signaling between valve interstitial cells (VICs) and macrophages. Specifically, we hypothesized that distinct mitochondrial hubs may modulate these interactions. Using machine learning and bulk transcriptomic data, we identified microsomal glutathione S-transferase 1 (MGST1), an enzyme located on the outer mitochondrial and endoplasmic reticulum membranes, as a hub gene with high predictive performance. Subsequent validation confirmed that MGST1 is functionally involved in calcification, as its expression was markedly upregulated under calcifying conditions. Molecular docking further predicted that ritlecitinib exhibits the highest binding affinity for MGST1, and this molecule was shown to ameliorate calcification. In conclusion, this study delineates a comprehensive molecular network of MRGs in CAVD pathogenesis and identifies MGST1 as a mitochondria‑related hub gene that is upregulated in CAVD and functionally promotes calcification in vitro.