Histone lactylation enhances m6A-mediated PDK4 stabilization to drive osteogenic differentiation in calcific aortic valve disease [RNAseq-PDK4]

Calcific aortic valvular disease (CAVD) is characterized by progressive thickening and calcification of the valvular leaflets. Emerging evidence suggests that glycolysis, particularly regulated by pyruvate dehydrogenase kinase 4 (PDK4), plays a significant role in calcification-related diseases. Nevertheless, the mechanisms by which PDK4 affects glycolysis and influences CAVD remain unexplored. This study investigated the contribution of PDK4 to glycolytic reprogramming and osteogenic differentiation in CAVD. Osteogenic differentiation of human valvular interstitial cells (VICs) and CAVD valves was associated with enhanced glycolysis, leading to increased lactate production that further promoted VICs' calcification. PDK4 expression was significantly upregulated in both osteogenically differentiated VICs and CAVD valves. Silencing PDK4 reduced osteogenic differentiation in VICs, whereas PDK4 overexpression aggravated differentiation and increased glycolytic activity. Mechanistically, PDK4 facilitated nuclear translocation of Yes-associated protein (YAP), a key regulator of the Hippo signaling pathway, thereby enhancing RUNX2 transcription and promoting osteogenic differentiation. Nuclear accumulation of lactate increased H3K18 lactylation, which stabilized PDK4 mRNA through the METTL3-m6A-YTHDF1 pathway, establishing a positive feedback loop. This study identifies mechanisms by which glycolysis drives CAVD progression and highlights PDK4 as a potential molecular target for therapeutic intervention.