In support of the possibility that colitis-associated inflammatory factors contribute to neuroinflammation, we observed increased plasma concentrations of TNFα, MCP-1/CCL2, IL-6, and IFNγ in colitic mice (Fig. 2a, b), as well as increased transcription of Tnf, Il1b, and Il6 in their brains (Fig. 2c). Here, CCL2 is linked to colitis.