Gegen Qinlian decoction inhibited M1 macrophage polarization and ulcerative colitis progression through regulating histone lactylation

Ulcerative colitis (UC) is a persistent inflammatory condition affecting the bowels. Gegen Qinlian decoction (GQD) has been widely used in the therapy of gastrointestinal diseases. We investigated the protective impacts and mechanism of GQD against UC. To establish the UC model, dextran sulfate sodium (DSS) was utilized. The disease activity index (DAI), colon length and colonic pathology were assessed to examine the impacts of GQD on UC. The level of pan-lysine lactylation (Pan kla) and specific sites were detected using western blot. Then, the inflammatory factors and the oxidative stress parameters were measured via the corresponding kits, respectively. Our findings demonstrated that GQD suppressed the lactate generation and LDH activity. The western blot revealed that GQD inhibited the expression of Pan kla and specific sites of H3K18la, H3K23la, H4K8la, and H4K12la. Furthermore, the suppressive effects on inflammation and oxidative stress caused by GQD were counteracted upon the exogenous lactate. GQD suppressed the phenotypic differentiation of M1 macrophages by reducing the expression of M1 markers, which was also reversed by exogenous lactate. In conclusion, GQD effectively suppressed UC progression through histone lactylation. Our results broadened the theoretical basis for the clinical use of GQD.