Autoimmune diabetes-dependent c-Maf SUMOylation licenses inflammatory bowel disease by reshaping the gut microbiota

We have previously demonstrated a critical role of c-Maf SUMOylation in the regulation of autoimmune diabetogenesis, but its physiological relevance to and potential clinical impact on gut inflammation need further elucidation. Here, integrating a 14-year population-based time-trend cohort study of 139,204 type 1 diabetes patients with experiments in non-obese diabetic mice, we illustrated that autoimmune diabetes confers resistance to colitis mediated by an impaired c-Maf SUMOylation-driven IL-21-IgA axis. Utilizing T cell-specific c-Maf SUMOylation site-mutated mice, we further demonstrated that SUMOylation-defective c-Maf enhances IL-21 expression in CD4+ T cells to promote fecal IgA production and colitis resistance via microbiota remodeling, specifically through Lactobacillus johnsonii enrichment and activating lithocholic acid (LCA)-mediated AMPK anti-inflammatory pathway. Pharmacological HDAC2 inhibition by BRD6688 promotes c-Maf-mediated IL-21 and suppresses colitis in PBMC-humanized mice. Altogether, we revealed how SUMOylation reciprocally modulates the inflammatory process between autoimmune diabetes and colitis in a T cell-restricted and single transcription factor-based manner.