Qing-Chang-Hua-Shi granule ameliorates DSS-induced colitis by activating NLRP6 signaling and regulating Th17/Treg balance

Background: Chinese herbal medicine Qing-Chang-Hua-Shi granule (QCHS) is widely used to treat ulcerative colitis in China. However, the molecular mechanisms of QCHS remains largely unknown. Purpose: To assess the therapeutic effects of QCHS on colitis and to reveal its mechanisms of action. Methods: The main components of QCHS were identified using a UHPLC-QTOF-MS method and the efficacy of QCHS was evaluated using an DSS-induced mice model. The inflammatory responses and mucosal integrity in colon were comprehensively assessed. Flow cytometry was used to analysis the proportion of Th17 and Treg cells. Detect the signal transduction of the NOD-like receptor family pyrin domain containing 6 (NLRP6) both in vitro and in vivo. Furthermore, siNLRP6 transfection was used to validate the functional targets of QCHS. Results: QCHS treatment significantly alleviated colitis in mice by improving symptoms and pathological damage. Moreover, QCHS treatment suppressed the inflammatory response and preserved the integrity of colon tissue. Most importantly, QCHS balanced the Th17/Treg response of UC mice. Mechanistically, by activating NLRP6 inflammasome pathway, QCHS regulated the maturation of interleukin (IL)-1 beta and IL-18 to affect inflammation and drive Th17 cell differentiation. Conclusions: The effect of QCHS on UC mice is dose-dependent, with high-dose QCHS being superior to 5-Amino-salicylic acid (200 mg/kg/day). QCHS acts through the NLRP6 signaling pathway to modulate Th17/Treg bal-ance, resulting in the protective effects against colitis. This study investigated the relevant pharmacological mechanisms of QCHS, providing further evidence for the application of QCHS in UC treatment.