The dual role of TRPA1 in dextran sulfate sodium (DSS)-induced murine colitis: Suppression alleviates acute inflammation but exacerbates subacute disease.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with limited treatment options. Transient receptor potential ankyrin 1 (TRPA1) has been implicated in inflammation and pain, but its role in UC remains a subject of debate. The current study investigated the effects of TRPA1 inhibition in both acute and subacute murine models of dextran sulfate sodium (DSS)-induced colitis. Genetic knockout of Trpa1 or pharmacological inhibition with A967079 significantly ameliorated inflammation in the acute model, reducing the disease activity index (DAI), colon shortening, histopathological damage, and TNF-α secretion from macrophages. In contrast, TRPA1 suppression exacerbated subacute colitis and worsened weight loss, DAI, colon shortening, and histopathology. Mechanistically, Trpa1 deletion promoted CD4+ T cell polarization toward the Th1 subtype in subacute colitis, increasing IFN-γ levels. These findings reveal a dual role for TRPA1 in colonic inflammation: it mediates pro-inflammatory effects primarily via innate immune cells in the acute phase but has anti-inflammatory effects by modulating adaptive immunity in the subacute phase. These findings provide new insights into the context-dependent roles of TRPA1 and suggest that TRPA1 may represent a context-specific and stage-dependent therapeutic target in UC.