AIM2 regulated by JAK3/STAT1 pathway promotes PANoptosis in intestinal barrier dysfunction caused by concomitant radiation and PD-1 Blockade.

Intestinal injury is a common and potentially life-threatening complication in patients receiving concurrent radiotherapy (RT) and anti-PD-1 immunotherapy (IO) for pelvic, abdominal, or retroperitoneal malignancies. Despite the therapeutic benefits of RT/IO combinations the mechanisms underlying RT/IO-induced enteritis remain poorly understood. This study investigates the role of Absent in melanoma 2 (AIM2)-mediated PANoptosis in intestinal barrier dysfunction during RT/IO-induced enteritis. Colonic epithelial cell models and murine models were utilized to assess the activation of PANoptosis pathways, barrier function, and inflammation. AIM2 expression was silenced using CRISPR-Cas9-mediated knockout. Western blotting and immunohistochemistry were employed to assess PANoptosis markers. Barrier function was evaluated using transepithelial electrical resistance (TEER) and FITC-dextran permeability assays. Quasi-targeted metabolomics identified metabolic alterations associated with intestinal injury. Combined RT and IO significantly exacerbated intestinal epithelial damage, as evidenced by increased PANoptosis and compromised barrier function both in vivo and in vitro. AIM2 expression was markedly upregulated following RT/IO treatment. RT/IO treatment activated the JAK3/STAT1 signaling pathway, and pretreatment with the JAK3 inhibitor AG490 inhibited AIM2 expression, while cellular AIM2 knockout attenuated PANoptosis markers, preserved tight junction protein ZO-1, and improved barrier function. Metabolomics analysis showed that RT/IO treatment significantly disturbed intestinal choline metabolism in mice, which may be related to the cell death pathway. Supplementation with choline or its metabolite trimethylamine N-oxide (TMAO), especially TMAO, upregulated JAK3/STAT1 and AIM2-PANoptosis pathways, and aggravated intestinal injury, whereas supplementation of mice with 3,3-Dimethyl-1-butanol (DMB) to reduce the production of TMAO reversed the activation of the choline-induced pathway and inflammatory response. AIM2-driven PANoptosis, activated by the JAK3/STAT1 pathway, plays a key role in RT/IO-induced intestinal damage. Elevated choline metabolism and TMAO accumulation further amplify this pathological process by enhancing JAK3/STAT1 and AIM2 activity. Inhibiting JAK3 or TMAO reduces PANoptosis, offering a potential preclinical treatment to alleviate RT/IO intestinal toxicity.