KLF5 Downregulation Links Impaired BNIP3‐Mediated Mitophagy to Inflammatory Valve Remodeling in Calcific Aortic Valve Disease

ABSTRACT Calcific aortic valve disease (CAVD) lacks effective drug therapy. This study integrated human valve transcriptomic datasets and tissue specimens, public single‐cell and spatial transcriptomics, primary human valvular interstitial cell (VIC) models, and ApoE −/− mice fed a high‐fat diet to define the role of KLF5 in VIC remodeling. KLF5 expression was reduced in calcified human valves and associated with hemodynamic severity; tissue and single‐cell analyses localized this reduction to VIC‐rich lesions and disease‐associated VIC states. In primary VICs, KLF5 overexpression suppressed, whereas KLF5 knockdown enhanced, osteogenic medium‐induced inflammatory signaling and mineralization. Systemic AAV‐mediated KLF5 overexpression attenuated valve dysfunction, leaflet thickening, mineral deposition, and BMP2 expression in ApoE −/− mice. Mechanistically, KLF5 loss increased cytosolic mtDNA accumulation and activated cGAS–STING and NLRP3‐associated signaling, whereas cGAS knockdown reduced downstream signaling and interferon‐stimulated gene induction. KLF5 directly activated the BNIP3 promoter and supported BNIP3‐mediated mitophagy. BNIP3 knockdown markedly reduced the ability of KLF5 overexpression to preserve mitophagic flux and restrain inflammatory signaling and mineralization, whereas BNIP3 re‐expression mitigated the corresponding phenotypes in KLF5‐deficient VICs. These findings identify a VIC‐centered KLF5–BNIP3 regulatory pathway that supports mitochondrial quality control and limits mtDNA‐sensitive sterile inflammation, providing a mechanistic rationale for future therapeutic investigation in CAVD.