Yushuo Ren, Xiaohui Liu, Boya Wang, Haoyuan Yin, Jiatong Zhao, Shuzi Xin, Hongli Wang, Yuchen Zhang, Xinyue Liu, Jingyu Liu, Rongxuan Hua, Xiang Tian, Yuhang Bian, Sijin Gu, Haoxuan Zhang, Tong Wei, Lei Gao, Xin Lu, Hongwei Shang, Han Gao, Jingdong Xu
Regulatory T cells (Tregs) maintain intestinal immune homeostasis, but their therapeutic potential is constrained by a fundamental paradox: the same plasticity that enables tissue repair renders FOXP3 vulnerable to degradation in chronic inflammation. Mechanistically, microbial metabolites (short-chain fatty acids, bile acids) and retinoic acid stabilize FOXP3 and induce RORγt⁺/GATA3⁺ Treg specialization. In contrast, inflammatory cytokines and succinate accumulation drive ER stress and post-translational FOXP3 degradation, leading to lineage instability in inflammatory bowel disease, colorectal cancer, and celiac disease. Current Tregs-based therapies-adoptive transfer, low-dose IL-2, CAR-Tregs, and microbiota consortia-have demonstrated safety profiles yet exhibit limited efficacy due to this inherent instability. Next-generation strategies therefore focus on actively stabilizing FOXP3 (e.g., gut-restricted HDAC inhibitors) and engineering exhaustion-resistant CAR-Tregs. Three questions remain for clinical translation: how to preserve Treg stability without compromising anti-tumor immunity; which biomarkers (succinate, TSDR methylation, FOXP3Δ2/FL ratio) predict response; and whether logic-gated CAR-Tregs can overcome exhaustion. Addressing these challenges will enable the development of precision Treg immunotherapy for intestinal diseases.