Curcumin Modulates TIGIT/Neuropilin-1 to Regulate T-Cell Immune Homeostasis in Ulcerative Colitis.

(1) Background: Ulcerative colitis (UC) is a persistent inflammatory condition of the intestine, characterized by dysregulated T cell-mediated immune responses. Curcumin (CUR), a common food additive and health supplement, is noted for possessing anti-inflammatory and immunomodulatory properties. Nevertheless, the molecular mechanisms underlying its therapeutic effects remain incompletely elucidated. This research aims to investigate the therapeutic mechanisms of CUR in UC, focusing on its role in restoring T cell homeostasis by modulating TIGIT and Neuropilin-1 (NRP1). (2) Methods: We employed a DSS-induced murine colitis model, combined with network pharmacology, molecular docking, protein-protein interaction docking, molecular dynamics simulations, and invitro assays with Jurkat T cells. (3) Results: CUR markedly ameliorated clinical manifestations and histopathology in DSS-treated mice, restoring the balance of T cell and memory T cell subsets. Computational predictions and experimental validation showed that CUR downregulated TIGIT and NRP1 expression in inflamed colonic tissue and directly inhibited their expression in activated T cells invitro. (4) Conclusions: This study reveals a novel immunoregulatory mechanism of this natural compound. These findings suggest CUR modulates TIGIT/NRP1 to inhibit excessive T cell activation and restore immune homeostasis in UC.