Compatibility of cold herb CP and hot herb AZ in Huanglian Ganjiang decoction alleviates colitis mice through M1/M2 macrophage polarization balance via PAK4-mediated glucose metabolism reprogramming

Ulcerative colitis (UC) is a chronic and non-specific inflammatory bowel disease. Huanglian Ganjiang decoction (HGD), derived from ancient book “Beiji Qianjin Yao Fang”, has been used to cure UC patients traditionally. Our previous findings demonstrated that compatibility of cold herb Coptis chinensis Franch. + Phellodendron chinense C.K.Schneid. (CP) and hot herb Angelica sinensis (Oliv.) Diels + Zingiber officinale Roscoe (AZ) in HGD synergistically improved colitis mice. This study elucidated compatibility mechanisms by which CP and AZ regulated inflammatory balance in colitis mice. Mice were induced by 3% DSS for 7 days to establish experimental colitis model, followed by the treatment of CP, AZ and CPAZ for another 7 days. M1/M2 macrophage polarization levels, glucose metabolites levels and PDK4 expression were detected using flow cytometry, western blot, immunofluorescence and targeted glucose metabolomics. Our data revealed that CP inhibited M1 macrophage polarization, decreased levels of inflammatory metabolites associated with TCA cycle, suppressed PDK4 expression and PDH (Ser-293) phosphorylation level. AZ promoted M2 macrophage polarization, increased levels of lactate axis metabolite lactate, upregulated PDK4 expression and PDH (Ser-293) phosphorylation level. TCA cycle blocker AG-221 and AAV-PDK4 partly abolished M1 macrophage polarization inhibition by CP. Lactate axis antagonist oxamate and PDK4 inhibitor DCA partly weakened M2 macrophage polarization activation by AZ. Taken together, compatibility of CP and AZ synergistically alleviated colitis mice through M1/M2 macrophage polarization balance via PAK4-mediated glucose metabolism reprogramming. Specifically, CP reduced M1 macrophage polarization by recovery of TCA cycle via PDK4 inhibition. AZ increased M2 macrophage polarization through activation of PDK4/lactate axis.