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Tawiah A, Cornick S, Moreau F, Gorman H, Kumar M, Tiwari S, Chadee K. High MUC2 Mucin Expression and Misfolding Induce Cellular Stress, Reactive Oxygen Production, and Apoptosis in Goblet Cells. Am J Pathol 2018; 188:1354-1373. [PMID: 29545196 DOI: 10.1016/j.ajpath.2018.02.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 02/06/2018] [Accepted: 02/20/2018] [Indexed: 12/20/2022]
Abstract
MUC2 mucin is a large glycoprotein produced by goblet cells that forms the protective mucus blanket overlying the intestinal epithelium as the first line of innate host defense. High MUC2 production in inflammatory bowel disease and infectious colitis depletes goblet cells and the mucus layer by an unknown mechanism. Herein, we analyzed the effect of high MUC2 biosynthesis on endoplasmic reticulum (ER) stress and apoptosis in goblet cells using a high MUC2-producing human goblet cell line (HT29-H) and an HT29-H clone (HT29-L) silenced for MUC2 expression by lentivirus-mediated shRNA. Goblet cell ER stress and apoptosis were quantified during early onset of dextran sulfate sodium-induced colitis in C57BL/6 and Math1M1GFP mice. Compared with HT29-L and MUC2 nonproducing Caco-2 cells, high MUC2-producing HT29-H cells had significantly increased ER stress and apoptosis after treatment with ER stress-inducing agents. Apoptosis was driven by increased misfolded MUC2 that triggered elevated levels of reactive oxygen species. Correcting MUC2 folding and inhibiting reactive oxygen species alleviated ER stress and rescued cells from apoptosis. During early-onset colitis, mucus hypersecretion caused severe ER stress and apoptosis of goblet cells that preceded absorptive epithelial cell damage. Thus, in gastrointestinal inflammation, high MUC2 biosynthesis and goblet cell apoptosis lead to a dysfunctional epithelial barrier. Enhancing MUC2 folding may help alleviate goblet cell depletion and maintain mucosal integrity.
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Affiliation(s)
- Adelaide Tawiah
- Department of Microbiology, Immunology and Infectious Diseases, Gastrointestinal Research Group, Snyder Institute for Chronic Diseases, Faculty of Medicine, University of Calgary Health Sciences Centre, Calgary, Alberta, Canada
| | - Steve Cornick
- Department of Microbiology, Immunology and Infectious Diseases, Gastrointestinal Research Group, Snyder Institute for Chronic Diseases, Faculty of Medicine, University of Calgary Health Sciences Centre, Calgary, Alberta, Canada
| | - France Moreau
- Department of Microbiology, Immunology and Infectious Diseases, Gastrointestinal Research Group, Snyder Institute for Chronic Diseases, Faculty of Medicine, University of Calgary Health Sciences Centre, Calgary, Alberta, Canada
| | - Hayley Gorman
- Department of Microbiology, Immunology and Infectious Diseases, Gastrointestinal Research Group, Snyder Institute for Chronic Diseases, Faculty of Medicine, University of Calgary Health Sciences Centre, Calgary, Alberta, Canada
| | - Manish Kumar
- Department of Microbiology, Immunology and Infectious Diseases, Gastrointestinal Research Group, Snyder Institute for Chronic Diseases, Faculty of Medicine, University of Calgary Health Sciences Centre, Calgary, Alberta, Canada
| | - Sameer Tiwari
- Department of Microbiology, Immunology and Infectious Diseases, Gastrointestinal Research Group, Snyder Institute for Chronic Diseases, Faculty of Medicine, University of Calgary Health Sciences Centre, Calgary, Alberta, Canada
| | - Kris Chadee
- Department of Microbiology, Immunology and Infectious Diseases, Gastrointestinal Research Group, Snyder Institute for Chronic Diseases, Faculty of Medicine, University of Calgary Health Sciences Centre, Calgary, Alberta, Canada.
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Abstract
The gastrointestinal tract is coated by a thick layer of mucus that forms the front line of innate host defense. Mucus consists of high molecular weight glycoproteins called mucins that are synthesized and secreted by goblet cells and functions primarily to lubricate the epithelium and protect it from damage by noxious substances. Recent studies have also suggested the involvement of goblet cells and mucins in complex immune functions such as antigen presentation and tolerance. Under normal physiological conditions, goblet cells continually produce mucins to replenish and maintain the mucus barrier; however, goblet cell function can be disrupted by various factors that can affect the integrity of the mucus barrier. Some of these factors such as microbes, microbial toxins and cytokines can stimulate or inhibit mucin production and secretion, alter the chemical composition of mucins or degrade the mucus layer. This can lead to a compromised mucus barrier and subsequently to various pathological conditions like chronic inflammatory diseases. Insight into how these factors modulate the mucus barrier in the gut is necessary in order to develop strategies to combat these disorders.
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Key Words
- Barrier function
- CD, Crohns disease
- ER stress
- ERAD, ER-associated protein degradation
- EhCP5, Entamoeba histolytica cysteine protease 5
- FAS, fatty acid synthase
- GI, gastrointestinal
- GalNAc, N-Acetylgalactosamine
- Goblet cell
- IBD
- IBD, Inflammatory bowel disease
- Innate defense
- LLO, Listeriolysin O
- LPS, Lipopolysaccharide
- MUC2
- MucBP, Mucin binding proteins
- Mucin
- SCFA, short chain fatty acids
- Secretory response
- UC, Ulcerative colitis
- UPR, unfolded protein response
- Unfolded protein response
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Affiliation(s)
- Steve Cornick
- Department of Microbiology; Immunology and Infectious Diseases; Snyder Institute for Chronic Diseases; Gastrointestinal Research Group; University of Calgary; Calgary, Alberta, Canada
| | - Adelaide Tawiah
- Department of Microbiology; Immunology and Infectious Diseases; Snyder Institute for Chronic Diseases; Gastrointestinal Research Group; University of Calgary; Calgary, Alberta, Canada
| | - Kris Chadee
- Department of Microbiology; Immunology and Infectious Diseases; Snyder Institute for Chronic Diseases; Gastrointestinal Research Group; University of Calgary; Calgary, Alberta, Canada
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Tawiah A, Moreau F, Chadee K. High MUC2 Production in Goblet Cells Induces ER Stress and Exhibit Increase Susceptibility to Apoptosis. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.148.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Adelaide Tawiah
- Microbiology, Immunology and Infectious DiseasesUniversity of CalgaryCalgaryAlbertaCanada
| | - France Moreau
- Microbiology, Immunology and Infectious DiseasesUniversity of CalgaryCalgaryAlbertaCanada
| | - Kris Chadee
- Microbiology, Immunology and Infectious DiseasesUniversity of CalgaryCalgaryAlbertaCanada
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Affiliation(s)
- Adelaide Tawiah
- MicrobiologyImmunology and Infectious Diseases University of CalgaryCalgaryABCanada
| | - France Moreau
- MicrobiologyImmunology and Infectious Diseases University of CalgaryCalgaryABCanada
| | - Kris Chadee
- MicrobiologyImmunology and Infectious Diseases University of CalgaryCalgaryABCanada
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