<p>by Huimin Liu, Yuzhen Wang, Ruiqing Yu, Kexin Liu, Dezhi Zheng, Bo Wang, Yuan Chang, Bing Liu, Xuetian Yue, Zhuanchang Wu, Chunyang Li, Xiaohong Liang, Chunhong Ma, Guohua Liu, Jianhua Li, Leiqi Xu, Lifen Gao</p> Macrophages play a pivotal role in the pathogenesis of inflammatory bowel disease (IBD). T-cell immunoglobulin and mucin domain-containing molecule 4 (TIMD4) is involved in the regulation of tissue-resident macrophages. TIMD4 expression is elevated in colonic tissues from patients with ulcerative colitis (UC) and mice with dextran sulfate sodium (DSS)-induced colitis, but its role in IBD pathogenesis remains unclear. In this study, we found that <i>Timd4</i> deficiency aggravated DSS-induced colitis, accompanied by increased infiltration of monocytes into the colonic tissues. Treatment with a CCR2 antagonist attenuated colonic inflammation and reduced monocyte infiltration into colonic tissues in <i>Timd4</i> KO mice. Mechanistically, in vitro studies revealed that TIMD4 stabilized the LKB1-STRAD-MO25 complex via its intracellular domain, thereby activating the AMPK pathway and suppressing NF-κB-dependent chemokine production in macrophages. Based on these findings, we designed a TIMD4-derived peptide and developed a macrophage-targeted nanoparticle system (T4<sub>(365–378)</sub>‑NPs). Treatment with T4<sub>(365–378)</sub>-NPs reduced P65 phosphorylation and attenuated DSS-induced colitis in mice. Treatment with either T4<sub>(365–378)</sub>-NPs or the CCR2 antagonist attenuated DSS-induced colitis, and no statistically significant differences in the assessed outcomes were detected between the two groups. Administration of T4<sub>(365–378)</sub>-NPs before DSS exposure also attenuated subsequent colitis. Furthermore, combining the T4<sub>(365–378)</sub>‑NPs with anti-α4β7 or anti-TNF-α antibodies produced greater improvements than either monotherapy in the DSS-induced colitis model. These findings support further preclinical evaluation of TIMD4-derived peptide delivery as a potential therapeutic approach for intestinal inflammation.