Fig. 8.

Gln promoted MUC2 maturation by stabilizing AGR2 redox homeostasis induced by O-GlcNAcylation of G6PD in burn infection. (A) O-GlcNAcylation levels in the distal colons after 5 days of glutamine supplementation in burn-infected mice (N = 3 per group). (B) Chemical enzyme labeling and biotinylation to detect G6PD O-GlcNAcylation (N = 3 per group). (C) GSH levels in distal colon tissue lysates (N = 3 per group). (D) GSH/GSSG in distal colon tissue lysates (N = 3 per group). (E) Immunoblot analysis of the cysteine thiol level of AGR2. Tissue lysates were incubated with Protein-Shifter Plus and subjected to SDS‒PAGE in the absence of BME (N = 3 per group). (F) Immunoblot analysis of the S-glutathionylation levels of total protein (N = 3 per group). (G) Co-IP showing S-glutathionylated AGR2 in tissue lysates (N = 3 per group). * Compared with sham group, # Compared with BI group, #P < 0.05; # #P < 0.01; # # #P < 0.001. (H) Immunoblotting for the expression of mature MUC2, immature MUC2, GRP78 and CHOP in the distal colon (N = 5 per group). (I) Representative AGR2 and MUC2 protein staining in colon sections. The yellow arrows indicate immature MUC2, and the red arrows indicate mature MUC2. (J) Proposed mechanism for the effect of Gln on promoting MUC2 maturation in burn-infected mice. . (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)