Li Minhao, Wang Tinglong, Yuan Mei
Department of General Surgery, Wuxi No.2 People's Hospital, Wuxi, China.
Department of Pharmacy, Nanxin Pharmaceutical, Nanjing, China.
Immunol Invest. 2025 Nov;54(8):1501-1523. doi: 10.1080/08820139.2025.2556790. Epub 2025 Sep 7.
This study aims to elucidate how butyrate, a short-chain fatty acid, regulates the Treg/Th17 balance in ulcerative colitis (UC) via the cAMP-PKA/mTOR signaling pathway, offering novel treatment strategies.
Dextran sulfate sodium (DSS) was used to induce ulcerative colitis in a mouse model. Various butyrate dosages were administered to the mice. The mice's body weight, colon length, spleen index (SI), and disease activity index (DAI) were all assessed.HE staining and Masson staining were used for histopathological evaluation. Immunohistochemistry and RT-qPCR were applied to detect fibrosis markers. Flow cytometry, RT-qPCR, and ELISA were employed to analyze immune cell subsets and cytokines. RT-qPCR and Western blotting were utilized to explore the cAMP-PKA/mTOR signaling pathway. Specific inhibitors were used to further confirm the mechanism of its action.
Butyrate treatmentreduced DAI and SI, and reversed pathological changes (weight loss, colon shortening, splenomegaly) in DSS-induced UC model mice, with the high-dose group showing the best recovery. It inhibited colon fibrosis,and decreased fibrosis markers. By regulating the regulatory T cell (Treg)/T helper 17 cell (Th17) balance, butyrate restored immune homeostasis. Flow cytometry showed DSS-induced immune imbalance was reversed in a dose-dependent manner. Additionally, butyrate modulated the cAMP-PKA/mTOR signaling pathway, reversing DSS-induced gene and protein expression changes. Specific inhibitor experiments confirmed that butyrate exerted its therapeutic effects via this pathway.
Butyrate can markedly alleviate acute UC intestinal inflammation and block chronic fibrosis progression. The bidirectional regulation of the cAMP-PKA/mTOR signaling pathway is the key mechanism for butyrate to restore immune homeostasis.
本研究旨在阐明短链脂肪酸丁酸如何通过环磷酸腺苷-蛋白激酶A/哺乳动物雷帕霉素靶蛋白（cAMP-PKA/mTOR）信号通路调节溃疡性结肠炎（UC）中的调节性T细胞（Treg）/辅助性T细胞17（Th17）平衡，从而提供新的治疗策略。
使用葡聚糖硫酸钠（DSS）诱导小鼠溃疡性结肠炎模型。给小鼠施用不同剂量的丁酸。评估小鼠的体重、结肠长度、脾脏指数（SI）和疾病活动指数（DAI）。采用苏木精-伊红（HE）染色和Masson染色进行组织病理学评估。应用免疫组织化学和逆转录定量聚合酶链反应（RT-qPCR）检测纤维化标志物。采用流式细胞术、RT-qPCR和酶联免疫吸附测定（ELISA）分析免疫细胞亚群和细胞因子。利用RT-qPCR和蛋白质印迹法探索cAMP-PKA/mTOR信号通路。使用特异性抑制剂进一步确认其作用机制。
丁酸治疗降低了DAI和SI，并逆转了DSS诱导的UC模型小鼠的病理变化（体重减轻、结肠缩短、脾肿大），高剂量组恢复最佳。它抑制结肠纤维化，并降低纤维化标志物。通过调节调节性T细胞（Treg）/辅助性T细胞17（Th17）平衡，丁酸恢复了免疫稳态。流式细胞术显示，DSS诱导的免疫失衡以剂量依赖性方式得到逆转。此外，丁酸调节cAMP-PKA/mTOR信号通路，逆转了DSS诱导的基因和蛋白表达变化。特异性抑制剂实验证实，丁酸通过该途径发挥其治疗作用。
丁酸可显著减轻急性UC肠道炎症并阻止慢性纤维化进展。cAMP-PKA/mTOR信号通路的双向调节是丁酸恢复免疫稳态的关键机制。
