The researchers began with evidence that T-cell immunoglobulin and mucin domain-containing molecule 4 (TIMD4), which regulates tissue-resident macrophages, was expressed at elevated levels in colonic tissue from patients with ulcerative colitis and in mice with dextran sulfate sodium–induced colitis. To investigate whether TIMD4 contributes protectively to disease, the team studied mice deficient in Timd4. After chemical exposure, these animals showed aggravated colitis and increased monocyte infiltration into colonic tissue. A CCR2 antagonist reduced both inflammation and monocyte infiltration in the deficient mice, indicating that CCR2-associated monocyte recruitment contributed at least partly to the phenotype.

Experiments with macrophages provided a mechanistic explanation for the nanoparticle design. Through its intracellular domain, TIMD4 stabilized the LKB1–STRAD–MO25 complex and activated the AMPK pathway. In macrophages, this signaling suppressed production of chemokines dependent on NF-κB. The researchers selected the TIMD4 amino-acid segment spanning residues 365–378 and delivered it in nanoparticles targeted to macrophages. In mice with dextran sulfate sodium–induced colitis, T4(365–378)-NPs reduced p65 phosphorylation, attenuated disease and limited monocyte recruitment into the colon. The assessed outcomes did not differ significantly between T4(365–378)-NPs and the CCR2 antagonist.

Administration of the nanoparticles before dextran sulfate sodium exposure also attenuated the subsequent colitis response, demonstrating protection in that preventive experimental setting. Combining T4(365–378)-NPs with either an anti-α4β7 antibody or an anti-TNF-α antibody produced greater improvements in the mouse disease measures than either monotherapy. The evidence therefore supports evaluating TIMD4-derived peptide delivery as a complementary strategy for intestinal inflammation, while the findings remain confined to a mouse model with selected mechanistic experiments conducted in cells.

Subject of Research: Preclinical TIMD4 peptide-nanoparticle treatment for intestinal inflammation in mice

Article Title: A macrophage-targeted TIMD4 Peptide-Nanoparticle attenuates colitis symptoms and monocyte recruitment in a mouse model

Article References: Liu, H., Wang, Y., Yu, R., Liu, K., Zheng, D., Wang, B., Chang, Y., Liu, B., Yue, X., Wu, Z., Li, C., Liang, X., Ma, C., Liu, G., Li, J., Xu, L., & Gao, L. (2026). A macrophage-targeted TIMD4 Peptide-Nanoparticle attenuates colitis symptoms and monocyte recruitment in a mouse model. PLOS Biology, 24(10), e3004056. https://doi.org/10.1371/journal.pbio.3004056

Image Credits: AI Generated

DOI: 10.1371/journal.pbio.3004056

Keywords: TIMD4, inflammatory bowel disease, colitis, macrophages, nanoparticles, monocyte recruitment, AMPK, NF-κB, CCR2, ulcerative colitis, macrophage-targeted, Peptide-Nanoparticle