Endoplasmic reticulum stress and inflammatory bowel disease

Area of Science:

• Cellular Biology
• Gastroenterology
• Immunology

Background:

• Endoplasmic reticulum (ER) stress, caused by protein misfolding, triggers the unfolded protein response (UPR) for adaptation.
• Genetic risk factors for inflammatory bowel disease (IBD), such as XBP1, AGR2, and ORMDL3, are involved in the UPR.
• The intestinal epithelium, particularly goblet and Paneth cells, is sensitive to UPR disturbances.

Purpose of the Study:

• To explore the role of the UPR in the pathogenesis of IBD.
• To investigate how genetic and environmental factors interact with the UPR in the context of IBD.
• To understand how a normally adaptive UPR can become a pathogenic mechanism in IBD.

Main Methods:

• Review of genetic loci associated with IBD and their involvement in the UPR.
• Examination of cellular sensitivity in the intestinal epithelium to UPR disturbances.
• Analysis of experimental models, such as Xbp1-deficient mice, to study spontaneous intestinal inflammation.
• Consideration of environmental factors that may intersect with the UPR.

Main Results:

• Genetic factors central to the UPR are linked to IBD risk.
• Intestinal epithelial cells, especially goblet and Paneth cells, are highly sensitive to UPR dysfunction.
• Mice with intestinal-specific Xbp1 deletion develop spontaneous inflammation resembling human IBD.
• Environmental factors can interact with genetic susceptibility to promote IBD through UPR dysregulation.

Conclusions:

• The UPR plays a critical role in maintaining intestinal homeostasis, and its dysregulation contributes to IBD.
• Gene-environment interactions involving the UPR are crucial in the development of IBD.
• Unresolved ER stress can transform the UPR from a protective response into a driver of intestinal inflammation.