GLP-1 Induces Barrier Protective Expression in Brunner's Glands and Regulates Colonic Inflammation

Area of Science:

• Gastroenterology
• Immunology
• Molecular Biology

Background:

• Glucagon-like peptide 1 (GLP-1) signaling demonstrates beneficial effects in inflammatory conditions.
• The GLP-1 receptor (GLP-1R) is highly expressed in the duodenum and Brunner's glands, suggesting localized roles.
• Investigating GLP-1's impact on gut inflammation is crucial for understanding its therapeutic potential.

Purpose of the Study:

• To investigate the effects of GLP-1 signaling on Brunner's glands and duodenal tissue.
• To determine the impact of GLP-1 on colonic inflammation, particularly in the context of inflammatory bowel disease (IBD).
• To explore the therapeutic potential of GLP-1 receptor agonists in a colitis model.

Main Methods:

• Transcriptome profiling of Brunner's glands from GLP-1R knockout and wild-type mice.
• Validation of gene expression using quantitative reverse transcription polymerase chain reaction (qRT-PCR).
• Assessment of liraglutide's efficacy in a T-cell driven adoptive transfer (AdTr) colitis mouse model.

Main Results:

• GLP-1R knockout and wild-type mice showed 722 differentially expressed genes in Brunner's glands.
• Upregulated transcripts post-GLP-1 dosing included IL-33, chemokine ligand 20 (CCL20), and mucin 5b.
• Liraglutide treatment reduced colonic inflammation and disease scores in the AdTr colitis model, with altered expression of GLP-1R, CCL20, and IL-33.

Conclusions:

• Interleukin-33 (IL-33), GLP-1R, and CCL20 are deregulated in human IBD.
• Prophylactic treatment with liraglutide ameliorates disease in an adoptive transfer colitis model.
• GLP-1 receptor agonists modulate gut homeostasis by affecting gene expression in both proximal and distal gut segments.