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Heazlewood CK, Cook MC, Eri R, Price GR, Tauro SB, Taupin D, Thornton DJ, Png CW, Crockford TL, Cornall RJ, Adams R, Kato M, Nelms KA, Hong NA, Florin THJ, Goodnow CC, McGuckin MA. Aberrant mucin assembly in mice causes endoplasmic reticulum stress and spontaneous inflammation resembling ulcerative colitis. PLoS Med 2008; 5:e54. [PMID: 18318598 PMCID: PMC2270292 DOI: 10.1371/journal.pmed.0050054] [Citation(s) in RCA: 541] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Accepted: 01/17/2008] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND MUC2 mucin produced by intestinal goblet cells is the major component of the intestinal mucus barrier. The inflammatory bowel disease ulcerative colitis is characterized by depleted goblet cells and a reduced mucus layer, but the aetiology remains obscure. In this study we used random mutagenesis to produce two murine models of inflammatory bowel disease, characterised the basis and nature of the inflammation in these mice, and compared the pathology with human ulcerative colitis. METHODS AND FINDINGS By murine N-ethyl-N-nitrosourea mutagenesis we identified two distinct noncomplementing missense mutations in Muc2 causing an ulcerative colitis-like phenotype. 100% of mice of both strains developed mild spontaneous distal intestinal inflammation by 6 wk (histological colitis scores versus wild-type mice, p < 0.01) and chronic diarrhoea. Monitoring over 300 mice of each strain demonstrated that 25% and 40% of each strain, respectively, developed severe clinical signs of colitis by age 1 y. Mutant mice showed aberrant Muc2 biosynthesis, less stored mucin in goblet cells, a diminished mucus barrier, and increased susceptibility to colitis induced by a luminal toxin. Enhanced local production of IL-1beta, TNF-alpha, and IFN-gamma was seen in the distal colon, and intestinal permeability increased 2-fold. The number of leukocytes within mesenteric lymph nodes increased 5-fold and leukocytes cultured in vitro produced more Th1 and Th2 cytokines (IFN-gamma, TNF-alpha, and IL-13). This pathology was accompanied by accumulation of the Muc2 precursor and ultrastructural and biochemical evidence of endoplasmic reticulum (ER) stress in goblet cells, activation of the unfolded protein response, and altered intestinal expression of genes involved in ER stress, inflammation, apoptosis, and wound repair. Expression of mutated Muc2 oligomerisation domains in vitro demonstrated that aberrant Muc2 oligomerisation underlies the ER stress. In human ulcerative colitis we demonstrate similar accumulation of nonglycosylated MUC2 precursor in goblet cells together with ultrastructural and biochemical evidence of ER stress even in noninflamed intestinal tissue. Although our study demonstrates that mucin misfolding and ER stress initiate colitis in mice, it does not ascertain the genetic or environmental drivers of ER stress in human colitis. CONCLUSIONS Characterisation of the mouse models we created and comparison with human disease suggest that ER stress-related mucin depletion could be a fundamental component of the pathogenesis of human colitis and that clinical studies combining genetics, ER stress-related pathology and relevant environmental epidemiology are warranted.
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Affiliation(s)
- Chad K Heazlewood
- Mucin and IBD Research Teams, Mucosal Diseases Program, Mater Medical Research Institute, and the University of Queensland, Aubigny Place, Mater Health Services, South Brisbane, Queensland, Australia
| | - Matthew C Cook
- Immunology and Inflammation Group, Phenomix Australia, Acton, Australia
| | - Rajaraman Eri
- Mucin and IBD Research Teams, Mucosal Diseases Program, Mater Medical Research Institute, and the University of Queensland, Aubigny Place, Mater Health Services, South Brisbane, Queensland, Australia
| | - Gareth R Price
- Molecular Genetics Team, Mater Medical Research Institute, and the University of Queensland, Aubigny Place, Mater Health Services, South Brisbane, Queensland, Australia
| | - Sharyn B Tauro
- Mucin and IBD Research Teams, Mucosal Diseases Program, Mater Medical Research Institute, and the University of Queensland, Aubigny Place, Mater Health Services, South Brisbane, Queensland, Australia
| | - Douglas Taupin
- Gastroenterology Unit, Canberra Hospital, Woden, Australia
| | - David J Thornton
- Wellcome Trust Centre for Cell Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Chin Wen Png
- Mucin and IBD Research Teams, Mucosal Diseases Program, Mater Medical Research Institute, and the University of Queensland, Aubigny Place, Mater Health Services, South Brisbane, Queensland, Australia
| | - Tanya L Crockford
- Nuffield Dept of Clinical Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Richard J Cornall
- Nuffield Dept of Clinical Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Rachel Adams
- Mucin and IBD Research Teams, Mucosal Diseases Program, Mater Medical Research Institute, and the University of Queensland, Aubigny Place, Mater Health Services, South Brisbane, Queensland, Australia
| | - Masato Kato
- Dendritic Cell Program, Mater Medical Research Institute, Aubigny Place, Mater Health Services, South Brisbane, Queensland, Australia
| | - Keats A Nelms
- Immunology and Inflammation Group, Phenomix Australia, Acton, Australia
| | - Nancy A Hong
- Phenomix Corporation, San Diego, California, United States of America
| | - Timothy H. J Florin
- Mucin and IBD Research Teams, Mucosal Diseases Program, Mater Medical Research Institute, and the University of Queensland, Aubigny Place, Mater Health Services, South Brisbane, Queensland, Australia
| | - Christopher C Goodnow
- Division of Immunology and Genetics and Australian Phenomics Facility, John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Michael A McGuckin
- Mucin and IBD Research Teams, Mucosal Diseases Program, Mater Medical Research Institute, and the University of Queensland, Aubigny Place, Mater Health Services, South Brisbane, Queensland, Australia
- * To whom correspondence should be addressed. E-mail:
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Papathanasiou P, Perkins AC, Cobb BS, Ferrini R, Sridharan R, Hoyne GF, Nelms KA, Smale ST, Goodnow CC. Widespread failure of hematolymphoid differentiation caused by a recessive niche-filling allele of the Ikaros transcription factor. Immunity 2003; 19:131-44. [PMID: 12871645 DOI: 10.1016/s1074-7613(03)00168-7] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A central issue in understanding the hematolymphoid system is the generation of appropriate mutant alleles in mice to reveal the function of regulatory genes. Here we describe a mouse strain, Plastic, with a point mutation in a zinc finger of Ikaros that disrupts DNA binding but preserves efficient assembly of the full-length protein into higher order complexes. Ikaros(Plastic) homozygosity is embryonically lethal with severe defects in terminal erythrocyte and granulocyte differentiation, excessive macrophage formation, and blocked lymphopoiesis, while heterozygotes display a partial block in lymphocyte differentiation. The contrast with more circumscribed effects of Ikaros alleles that ablate the full-length protein highlights the importance in mammals of generating recessive niche-filling alleles that inactivate function without creating a void in multimolecular assemblies.
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Affiliation(s)
- Peter Papathanasiou
- Australian Cancer Research Foundation Genetics Laboratory and Medical Genome Centre, John Curtin School of Medical Research, Australian National University, ACT 2601, Canberra, Australia
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Jun JE, Wilson LE, Vinuesa CG, Lesage S, Blery M, Miosge LA, Cook MC, Kucharska EM, Hara H, Penninger JM, Domashenz H, Hong NA, Glynne RJ, Nelms KA, Goodnow CC. Identifying the MAGUK protein Carma-1 as a central regulator of humoral immune responses and atopy by genome-wide mouse mutagenesis. Immunity 2003; 18:751-62. [PMID: 12818157 DOI: 10.1016/s1074-7613(03)00141-9] [Citation(s) in RCA: 257] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In a genome-wide ENU mouse mutagenesis screen a recessive mouse mutation, unmodulated, was isolated with profound defects in humoral immune responses, selective deficits in B cell activation by antigen receptors and T cell costimulation by CD28, and gradual development of atopic dermatitis with hyper-IgE. Mutant B cells are specifically defective in forming connections between antigen receptors and two key signaling pathways for immunogenic responses, NF-kappaB and JNK, but signal normally to calcium, NFAT, and ERK. The mutation alters a conserved leucine in the coiled-coil domain of CARMA-1/CARD11, a member of the MAGUK protein family implicated in organizing multimolecular signaling complexes. These results define Carma-1 as a key regulator of the plasticity in antigen receptor signaling that underpins opposing mechanisms of immunity and tolerance.
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Affiliation(s)
- Jesse E Jun
- Australian Cancer Research Foundation Genetics Laboratory and Medical Genome Centre, John Curtin School of Medical Research, Australian National University, ACT 2601, Canberra, Australia
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Abstract
The outstanding problems facing immunology are whole system issues: curing allergic and autoimmune disease and developing vaccines to stimulate stronger immune responses against pathogenic organisms and cancer. We hope that the human genome sequence will reveal the molecular checks and balances that ensure both an effective immunogenic response against pathogenic microorganisms and a suitably tolerogenic response to self antigens and innocuous environmental antigens. Three synergistic approaches--sequence homology searches, messenger RNA expression profiling on microarrays, and mutagenesis in mice--provide the best opportunities to reveal, in the genome sequence, key proteins and pathways for targeting by new immunomodulatory treatments.
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Affiliation(s)
- A M Fahrer
- ACRF Genetics Laboratory and Medical Genome Centre, John Curtin School of Medical Research, Australian National University, Canberra.
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