Reprogramming gut microenvironment for the treatment of acute severe ulcerative colitis via a synergistic therapy of necroptosis blockade and organoid transplantation.

Acute severe ulcerative colitis (ASUC) now imposes an increasing global burden, yet lacks broadly effective therapeutic options. While organoid transplantation represents a promising approach for intestinal injuries, its efficacy for ASUC treatment remains suboptimal. Here, we elucidate the intrinsic mechanism of RIPK1 involvement in necroptosis initiation, and further develop an organoid-based dual-axis therapeutic paradigm for ASUC. We identified that RIPK1 undergoes PIAS1-catalyzed SUMO1 modification at lysine 305, which promotes its compartmentalization within phase-separated structures, thereby serving as nucleation platforms for accelerating RIPK3 amyloid fibril assembly. Interfering with phase separation of RIPK1 suppresses necroptosis in intestinal cells and colonic organoids in vitro, as well as alleviates intestinal injury and reduces mortality in vivo. Notably, while colonic organoid transplantation showed limited therapeutic efficacy in ASUC, a synergistic therapy combining necroptosis blockade and organoid transplantation effectively reduced inflammatory damage and enhanced epithelial regeneration by reprogramming the intestinal microenvironment. These findings suggest that the SUMO1-RIPK1 axis functions as a druggable checkpoint governing necroptotic cell fate and presents a clinically actionable strategy to potentiate regenerative medicine paradigms in ASUC pathogenesis.