Furthermore, Wu et al revealed that TREM1 overexpression in a colitis model exacerbated visceral hypersensitivity and depressive-like behaviors by amplifying microglial activation in the anterior cingulate cortex, while TREM1 deficiency mitigated these effects.[31] This underscored TREM1’s dual role in both peripheral and central inflammatory cascades, which might disrupt 5-HT synthesis via pro-inflammatory cytokines that inhibited tryptophan hydroxylase activity. The gene discussed is TREM1; the disease is colitis.