Figure 1.

Enteric glial cells express MHC-II when stimulated with IFNγ and LPS. (A) Schematic showing enteric glial cells expressing MHC-II molecules as a response to exposure to 1 μg IFNγ and 0.3 mg/kg LPS. (B) Schematic showing the gene-targeting strategy in Sox10^CreERT2;IAB^fl/fl (glial^MHC2KO) mice. Tamoxifen-sensitive Cre^ERT2 expression is confined to glia by the Sox10 promoter and excises the floxed H2-Ab1 exon 1 loci. (C) Schematic showing the proinflammatory exposure protocol. (D) Representative confocal images of GFAP (grey) and MHC-II (red) immunofluorescence labeling in enteric ganglia of glial^MHC2KO (knockout [KO]) vs wild-type littermates when pretreated with IFNγ and then challenged with LPS or saline control. Enteric glia express MHC-II when stimulated with IFNγ and LPS. Muscularis macrophages (Mac) bordering enteric ganglia show constitutive MHC-II expression in all conditions. (E) Orthogonal views of confocal z-stacks show MHC-II (red) labeling in GFAP-expressing (grey) enteric glia. (F) Line-scans through enteric ganglia show co-expression of MHC-II (red) and GFAP (blue) labeling. (G) Quantified mean fluorescent intensity of MHC-II labeling on GFAP-expressing enteric glia in the myenteric plexus (n = 7–11 mice). Two-way analysis of variance with Tukey-corrected multiple comparisons; ∗P < .05, ∗∗∗∗P < .0001). (H) Representative confocal images of GFAP (grey), MHC-II (red), and CD74 (cyan) immunolabeling in wild-type animals treated with IFNγ and LPS show a neuronal and glial distribution of CD74. (I) Line-scans through enteric ganglia show minimal overlap between MHC-II (red) and CD74 (green) in GFAP-expressing (blue) enteric glia. Scale bars: 50 μm. IP, intraperitoneally.