When the Virus Leaves But the Lock Stays: Post-Viral Epigenetic Silencing in Gut Dysfunction and… — section

Once inside, butyrate serves two functions simultaneously. First, as an oxidative substrate — entering the TCA cycle via β-oxidation and Complex II to generate the ATP that sustains colonocyte barrier function, tight junction maintenance, and anti-inflammatory signaling. Second, and critically for this discussion, as an HDAC inhibitor. Butyrate inhibits primarily Class I and IIa HDACs, maintaining an acetylated, transcriptionally permissive chromatin state across hundreds of genes that govern differentiation, barrier integrity, mucosal immunity regulation, and colonocyte metabolic identity.