Gut microbiota‐derived butyric acid regulates calcific aortic valve disease pathogenesis by modulating GAPDH lactylation and butyrylation

The involvement of gut microbiota in calcific aortic valve disease (CAVD) pathogenesis remains underexplored. Here, we provide evidence for a strong association between the gut microbiota and CAVD development. ApoE^-/- mice were stratified into easy- and difficult- to calcify groups using neural network and cluster analyses, and subsequent faecal transplantation and dirty cage sharing experiments demonstrated that the microbiota from difficult-to-calcify mice significantly ameliorated CAVD. 16S rRNA sequencing revealed that reduced abundance of <i>Faecalibacterium prausnitzii</i> (<i>F. prausnitzii</i>) was significantly associated with increased calcification severity. Association analysis identified <i>F. prausnitzii</i>-derived butyric acid as a key anti-calcific metabolite. These findings were validated in a clinical cohort (25 CAVD patients vs. 25 controls), where serum butyric acid levels inversely correlated with disease severity. Functional experiments showed that butyric acid effectively hindered osteogenic differentiation in human aortic valve interstitial cells (hVICs) and attenuated CAVD progression in mice. Isotope labeling and ¹³C flux analyses confirmed that butyric acid produced in the intestine can reach heart tissue, where it reshapes glycolysis by specifically modifying GAPDH. Mechanistically, butyric acid-induced butyrylation (Kbu) at lysine 263 of GAPDH competitively inhibited lactylation (Kla) at the same site, thereby counteracting glycolysis-driven calcification. These findings uncover a novel mechanism through which <i>F. prausnitzii</i> and its metabolite butyric acid contribute to the preservation of valve function in CAVD, highlighting the gut microbiota-metabolite-glycolysis axis as a promising therapeutic target.