Enteric Glia Modulate Macrophage Phenotype and Visceral Sensitivity following Inflammation

Mechanisms resulting in abdominal pain include altered neuro-immune interactions in the gastrointestinal tract, but the signaling processes that link immune activation with visceral hypersensitivity are unresolved. We hypothesized that enteric glia link the neural and immune systems of the gut and that communication between enteric glia and immune cells modulates the development of visceral hypersensitivity. To this end, we manipulated a major mechanism of glial intercellular communication that requires connexin-43 and assessed the effects on acute and chronic inflammation, visceral hypersensitivity, and immune responses. Deleting connexin-43 in glia protected against the development of visceral hypersensitivity following chronic colitis. Mechanistically, the protective effects of glial manipulation were mediated by disrupting the glial-mediated activation of macrophages through the macrophage colony-stimulating factor. Collectively, our data identified enteric glia as a critical link between gastrointestinal neural and immune systems that could be harnessed by therapies to ameliorate abdominal pain. [Display omitted] •Enteric glia regulate visceral hypersensitivity during chronic inflammation•Glial mechanisms include connexin-43 and M-CSF production•Glial M-CSF modulates muscularis macrophage activation•Inflammation-induced glial M-CSF production is regulated by Cx43, PKC, and TACE Grubišić et al. report that enteric glia regulate macrophage activation and visceral sensitivity following intestinal inflammation through mechanisms that require glial connexin-43 (Cx43) and macrophage colony-stimulating factor (M-CSF) production. Proinflammatory signals induce glial Cx43-dependent M-CSF production through protein kinase C (PKC) and tumor necrosis factor (TNF)-alpha converting enzyme (TACE).