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Bleich A, Hopf S, Hedrich H, van Lith H, Li F, Sartor RB, Mähler M. Genetic dissection of granulomatous enterocolitis and arthritis in the intramural peptidoglycan-polysaccharide-treated rat model of IBD. Inflamm Bowel Dis 2009; 15:1794-802. [PMID: 19526527 PMCID: PMC2889022 DOI: 10.1002/ibd.21018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Accepted: 05/06/2009] [Indexed: 12/14/2022]
Abstract
BACKGROUND Inflammatory arthropathies are common extraintestinal manifestations of inflammatory bowel diseases (IBD). As genetic susceptibility plays an important role in the etiology of IBD, we questioned how granulomatous enterocolitis and arthritis are genetically controlled in an experimental animal model displaying both conditions. METHODS Chronic intestinal and systemic inflammation was induced by intramural injection of peptidoglycan-polysaccharide (PG-PS) polymers in the ileocecal region of female F2 progeny derived from susceptible LEW and resistant F344 rats. Animals were followed for 24 days after injection and phenotyped by evaluating gross gut lesions, liver weight and granulomas, hematocrit, white blood cell count, and change in rear ankle joint diameters. Coinheritance of the phenotypic parameters with polymorphic DNA markers was analyzed by genome-wide quantitative trait locus (QTL) analysis. RESULTS Linkage analysis revealed significant QTLs for enterocolitis and/or related phenotypes (liver granulomas, white blood cell count) on chromosomes 8 and 17. The QTL on chromosome 8 also showed suggestive linkage to arthritis. Significant QTLs for arthritis were detected on chromosomes 10, 13, 15, and 17. Analyses of the modes of inheritance showed arthritogenic contributions by both parental genomes. In addition, several other loci with suggestive evidence for linkage to 1 or several phenotypes were found. CONCLUSIONS Susceptibility to PG-PS-induced chronic intestinal and systemic inflammation in rats is under complex multigenic control in which the genetic loci regulating arthritis are largely different from those controlling enterocolitis. Possible candidate genes within these QTL (including Tnfrsf11a/RANK, Gpc5, Il2ra, and Nfrkb) are also implicated in the respective human diseases.
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Affiliation(s)
- A. Bleich
- Institute for Laboratory Animal Science and Central Animal Facility, Hannover Medical School, Hannover, Germany
| | - S. Hopf
- Institute for Laboratory Animal Science and Central Animal Facility, Hannover Medical School, Hannover, Germany
| | - H.J. Hedrich
- Institute for Laboratory Animal Science and Central Animal Facility, Hannover Medical School, Hannover, Germany
| | - H.A. van Lith
- Department of Animals, Science and Society, Division of Laboratory Animal Science, Faculty of Veterinary Medicine, and Rudolf Magnus Institute of Neuroscience, Utrecht University, Utrecht, The Netherlands
| | - F. Li
- Center for Gastrointestinal Biology and Disease, University of North Carolina, Chapel Hill, USA
| | - R. Balfour Sartor
- Center for Gastrointestinal Biology and Disease, University of North Carolina, Chapel Hill, USA
| | - M. Mähler
- Institute for Laboratory Animal Science and Central Animal Facility, Hannover Medical School, Hannover, Germany
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Sartor RB. Microbial-host interactions in inflammatory bowel diseases and experimental colitis. Nestle Nutr Workshop Ser Pediatr Program 2009; 64:121-32; discussion 132-7, 251-7. [PMID: 19710519 DOI: 10.1159/000235787] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
UNLABELLED The inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC), are immunologically mediated with genetic and environmental influences. Genetic factors include defective immunoregulation, mucosal integrity/repair and bacterial killing. Commensal bacteria activate pathogenic bacterial antigen-specific effector T cells that cause chronic inflammation in genetically susceptible hosts but induce protective immune responses in normal subjects. Both host and microbial specificities are important. Some bacterial species are aggressive, some are neutral and others protective, but each species has different effects in various hosts. Molecular techniques demonstrate contraction of certain bacterial populations in IBD, especially clostridial subsets, and expansion of others, including Enterobacteriaceae. The balance of beneficial and detrimental bacterial species determines homeostasis vs. inflammation; this balance can be manipulated by antibiotics, probiotics and prebiotics to treat and prevent relapses of IBD. Adherent/invasive Escherichia coli that adhere to and invade epithelial cells and resist killing by macrophages are increased in ileal CD. HYPOTHESIS Invasive, translocating, intracellular commensal bacteria induce Th1 and Th17 responses that cause CD in susceptible individuals with genetically determined innate immune defects. UC is caused by bacterial metabolic products that induce epithelial injury by blocking epithelial metabolism or overwhelming the genetically susceptible host's ability to degrade reactive oxygen species.
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Affiliation(s)
- R Balfour Sartor
- Departments of Medicine, Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA.
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103
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Hoffmann M, Kim SC, Sartor RB, Haller D. Enterococcus faecalis strains differentially regulate Alix/AIP1 protein expression and ERK 1/2 activation in intestinal epithelial cells in the context of chronic experimental colitis. J Proteome Res 2009; 8:1183-92. [PMID: 19166300 DOI: 10.1021/pr800785m] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Monoassociation of germfree Interleukin 10 gene deficient (IL-10-/-) 129SvEv but not wild-type mice with Enterococcus faecalis induces severe chronic colitis. Bacterial strain-specific effects on the development of chronic intestinal inflammation are not understood. We investigated the molecular mechanisms of E. faecalis OG1RF (human clinical isolate, colitogenic) and E. faecalis ms2 (endogenous isolate from an IL-10-/- mouse) in initiating chronic experimental colitis using IL-10-/- mice. Monoassociation of IL-10-/- mice for 14 weeks revealed significant differences in colonic inflammation (3.6 +/- 0.2 and 2.4 +/- 0.6 for OG1RF and ms2, respectively) (n = 5 mice in each group) (histological scoring (0-4)). Consistent with the tissue pathology, gene expression of the pro-inflammatory chemokine interferon-gamma inducible protein-10 (IP-10) was significantly higher in intestinal epithelial cells (IEC) derived from E. faecalis OG1RF monoassociated IL-10-/- mice. We further compared the differentially E. faecalis induced colitis on the epithelial level by 2D-SDS PAGE coupled with MALDI-TOF MS. Proteome analysis identified 13 proteins which were differentially regulated during disease progression in the epithelium of E. faecalis-monoassociated IL-10-/- mice. Regulation of Alix/AIP1 protein expression and ERK1/2 phosphorylation was validated in primary IEC and epithelial cell lines, suggesting a protective role for Alix/AIP1 in the process of disease progression. Alix/AIP1 protein expression was further characterized in epithelial cell lines using siRNA-mediated knock-down. Our study demonstrates E. faecalis strain-specific induction of colitis in IL-10-/- mice after 14 weeks of monoassociation. Our study suggests that Alix/AIP1 protein expression and ERK1/2 activation are decreased in severe colitis.
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Affiliation(s)
- Micha Hoffmann
- Chair for Biofunctionality, ZIEL-Research Center for Nutrition and Food Science, Technische Universitat Munchen, 85350 Freising-Weihenstephan, Germany
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Moran JP, Walter J, Tannock GW, Tonkonogy SL, Sartor RB. Bifidobacterium animalis causes extensive duodenitis and mild colonic inflammation in monoassociated interleukin-10-deficient mice. Inflamm Bowel Dis 2009; 15:1022-31. [PMID: 19235917 PMCID: PMC2764742 DOI: 10.1002/ibd.20900] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND We recently showed that Bifidobacterium animalis is more prevalent within the colons of interleukin (IL)-10-deficient (-/-) mice than in wildtype (WT) animals colonized with the same specific pathogen-free (SPF) fecal contents. Here we tested the ability of this organism to cause T-cell-mediated intestinal inflammation by introducing it into germ-free (GF) IL-10-/- mice. METHODS GF IL-10-/- or WT mice were monoassociated with Bifidobacterium animalis subsp. animalis ATCC (American Type Culture Collection, Manassas, VA) 25527(T) or with B. infantis ATCC 15697(T). Inflammation was measured by blinded histologic scores of the duodenum, cecum, and colon and by spontaneous secretion of IL-12/IL-23 p40 from colonic explants. Bacterial antigen-specific CD4(+) mesenteric lymph node (MLN) T-cell recall responses were measured in response to antigen-presenting cells (APC) pulsed with bacterial lysates. RESULTS B. animalis caused marked duodenal inflammation and mild colitis in monoassociated IL-10-/- mice, whereas the intestinal tracts of WT animals remained free of inflammation. B. infantis colonization resulted in mild inflammation in the duodena of IL-10-/- mice. CD4(+) MLN T cells from B. animalis monoassociated IL-10-/- mice secreted high levels of IFN-gamma and IL-17 in response to B. animalis lysate. B. animalis equally colonized the different intestinal regions of WT and IL-10-/- mice. CONCLUSIONS B. animalis, a traditional probiotic species that is expanded in experimental colitis in this model, induces marked duodenal and mild colonic inflammation and TH1/TH17 immune responses when introduced alone into GF IL-10-/- mice. This suggests a potential pathogenic role for this commensal bacterial species in a susceptible host.
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Affiliation(s)
- James P. Moran
- Center for Gastrointestinal Biology and Disease, Univ. of North Carolina, Chapel Hill, NC
| | | | | | - Susan L. Tonkonogy
- Center for Gastrointestinal Biology and Disease, Univ. of North Carolina, Chapel Hill, NC, North Carolina State Univ. College of Veterinary Medicine, Raleigh, NC
| | - R. Balfour Sartor
- Center for Gastrointestinal Biology and Disease, Univ. of North Carolina, Chapel Hill, NC
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Kim JS, An H, Rieter WJ, Esserman D, Taylor-Pashow KML, Sartor RB, Lin W, Lin W, Tarrant TK. Multimodal optical and Gd-based nanoparticles for imaging in inflammatory arthritis. Clin Exp Rheumatol 2009; 27:580-586. [PMID: 19772788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
OBJECTIVES This report documents a multimodal nanoparticle (MNP) contrast agent, containing embedded luminophores and surface-immobilized gadolinium chelates, as a contrast agent of inflamed synovium in a collagen induced arthritis (CIA) model. METHODS DBA-1J mice were immunized for CIA and imaged after disease onset by two independent modalities. After intravenous administration of MNP contrast, optical and magnetic resonance images were obtained and clinical disease was scored, which was followed by processing of hindlimbs for immunofluorescence and confocal microscopy. RESULTS We show a correlation between disease severity and MNP optical luminescence that is dose dependent. Immunofluorescence of hindlimb sections reveal that MNP-labeled cells are monocytes/macrophages within the inflamed synovium. Magnetic resonance (MR) relaxation time maps, which determine the quantitative measure of T1 and T2 values at each imaging voxel, demonstrated a decreasing T2 signal in actively inflamed joints that was more pronounced earlier rather than later during disease. CONCLUSIONS MNPs containing surface-immobilized gadolinium chelates and embedded luminophores are potential dual-modality contrast agents in inflammatory arthritis and localize to monocytes/macrophages within inflamed synovium.
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Affiliation(s)
- J S Kim
- Department of Chemistry, Division of Rheumatology, Allergy, and Immunology, University of North Carolina School of Medicine, Chapel Hill, USA
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Abstract
BACKGROUND While others have described gene expression patterns in humans with inflammatory bowel diseases and animals with chemically induced colitis, a genome-wide comparison of gene expression in genetically susceptible animals that develop spontaneous colitis has not been reported. METHODS We used microarray technology to compare gene expression profiles in cecal specimens from specific pathogen-free IL10-deficient (IL10-/-) mice with colitis and normal wildtype (WT) mice. RNA isolated from ceca of IL10-/- and WT mice was subjected to microarray analysis. The results were confirmed by real-time polymerase chain reaction (PCR) and immunofluorescence microscopy of selected molecules. Expression of the selected genes in dextran sodium sulfate (DSS)-treated mice with colitis and epithelial cell lines activated with pathophysiologic stimuli was measured by real-time PCR. RESULTS Histological inflammation of the colon and IL-12/23p40 secretion from intestinal explants were greater in IL10-/- and DSS-treated mice versus WT and untreated mice. Microarray analysis demonstrated >10-fold induction of the following molecules in the ceca of IL10-/- mice: mitochondrial ribosomal protein-L33, aquaporin-4, indoleamine-pyrrole-2,3-dioxygenase, and MHC class II with 63, 25, 20, and 12-fold increases, respectively. Cytochrome-P450, pancreatic lipase-related protein-2, and transthyretin were downregulated in IL10-/- mice. MHC II was increased throughout the colon, and aquaporin-4 was increased in the basolateral aspect of cecal epithelial cells. MHC II mRNA was increased in epithelial cells treated with IFN-gamma, but not TNF or Toll-like receptor ligands. CONCLUSIONS Although most upregulated genes in experimental colitis are immune-related, aquaporin-4 and mitochondrial ribosomal protein-L33, which have not been previously associated with inflammation, were most highly upregulated.
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Affiliation(s)
| | | | - R. Balfour Sartor
- Corresponding author: Department of Medicine, Division of Gastroenterology and Hepatology, 7317 MBRB/CB# 7032, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, Phone: 919-966-0149, Fax: 919-843-6899,
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Packey CD, Sartor RB. Commensal bacteria, traditional and opportunistic pathogens, dysbiosis and bacterial killing in inflammatory bowel diseases. Curr Opin Infect Dis 2009; 22:292-301. [PMID: 19352175 DOI: 10.1097/qco.0b013e32832a8a5d] [Citation(s) in RCA: 254] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW The authors present evidence published during the past 2 years of the roles of commensal and pathogenic bacteria in the pathogenesis of the inflammatory bowel diseases. RECENT FINDINGS Rodent models conclusively implicate commensal enteric bacteria in chronic, immune-mediated, experimental colitis, and genetically determined defects in bacterial killing by innate immune cells are found in a subset of patients with Crohn's disease. There is no evidence that a single pathogen, including Mycobacterium avium subspecies paratuberculosis, causes Crohn's disease or ulcerative colitis. However, adherent/invasive Escherichia coli are associated with ileal Crohn's disease, with the mechanisms and genetics of adherent/invasive E. coli virulence being elucidated. Molecular characterization of the microbiota in patients with inflammatory bowel diseases reveals decreased biodiversity of commensal bacteria, most notably the phyla Bacteroidetes and Firmicutes, including the clinically relevant Faecalibacterium prausnitzii, and increased E. coli concentrations. VSL#3 is one probiotic preparation shown to be efficacious in certain clinical situations in small clinical trials. SUMMARY Further characterization of altered microbiota in patients with inflammatory bowel diseases and linking dysbiosis with host genetic alterations in immunoregulation, innate microbial killing and barrier function are critical, so that individualized treatments to increase beneficial commensals and their metabolic products (probiotic and prebiotic administration) and diminish deleterious species such as adherent/invasive E. coli can be tailored for defined patient subsets.
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Affiliation(s)
- Christopher D Packey
- Department of Medicine, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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108
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Albright CA, Sartor RB, Tonkonogy SL. Endogenous antigen presenting cell-derived IL-10 inhibits T lymphocyte responses to commensal enteric bacteria. Immunol Lett 2009; 123:77-87. [PMID: 19428554 DOI: 10.1016/j.imlet.2009.02.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 12/17/2008] [Accepted: 02/16/2009] [Indexed: 01/25/2023]
Abstract
Interleukin-10 deficient (IL-10-/-) mice develop chronic T cell-mediated colitis when colonized with normal commensal bacteria, but germ-free (GF) IL-10-/- mice remain disease-free. Antigen presenting cells (APC) secrete regulatory cytokines that help determine T lymphocyte activation or tolerance. CD4(+) T cells from the mesenteric lymph nodes of inflamed IL-10-/- mice secrete more IFN-gamma and IL-17 when cultured with cecal bacterial lysate-pulsed splenic APC from IL-10-/- mice than when cultured with normal control APC. GF IL-10-/- APC induce similar IFN-gamma and IL-17 responses; therefore, the functional difference between normal and IL-10 deficient APC is inherent to the lack of IL-10 and not secondary to inflammation. Bacterial lysate-pulsed normal APC cultured with CD4(+) cells from colitic IL-10-/- mice or with exogenous IFN-gamma secrete higher amounts of IL-10 compared to the same APC cultured with naïve T cells. APC enriched for CD11c(+) cells are potent activators of IFN-gamma and IL-17 production by CD4(+) cells from IL-10-/- mice. These APC also produce IL-12/IL-23 p40 and IL-10. Recombinant IL-10 suppressed and anti-IL-10 receptor antibody increased IFN-gamma, IL-17 and IL-12/IL-23 p40 production in bacterial lysate-pulsed APC and plus CD4(+) T cell co-cultures. Taken together, our results show that endogenous IL-10 produced by APC inhibits responses to commensal bacteria and influences the ability of APC to stimulate IFN-gamma-producing effector lymphocytes, which reciprocally, induce IL-10 production by APC. Cytokines produced by APC are an important determinant of pathogenic versus protective mucosal immune responses to colonic bacterial stimulation.
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Affiliation(s)
- Carol A Albright
- Center for Gastrointestinal Biology and Disease, University of North Carolina, Chapel Hill, USA
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109
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Walton KLW, Holt L, Sartor RB. Lipopolysaccharide activates innate immune responses in murine intestinal myofibroblasts through multiple signaling pathways. Am J Physiol Gastrointest Liver Physiol 2009; 296:G601-11. [PMID: 19136385 PMCID: PMC2660170 DOI: 10.1152/ajpgi.00022.2008] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Myofibroblasts (MF) play an important role in intestinal wound healing. A compromised epithelial barrier exposes intestinal subepithelial MF to luminal bacterial products. However, responses of murine intestinal MF to bacterial adjuvants and potential roles of intestinal MF in innate immune responses are not well defined. Our aims in this study were to determine innate immune responses and intracellular signaling pathways of intestinal MF exposed to LPS, a prototypic Toll-like receptor (TLR) ligand. Expression of TLR4 in primary murine intestinal MF cultures was confirmed by RT-PCR and Western blotting. LPS-induced secretion of prostaglandin E2 (PGE2), interleukin (IL)-6, and keratinocyte-derived chemokines (KC) was measured by ELISA. Intracellular responses to LPS were assessed by Western blotting for NF-kappaB p65, Ikappa-Balpha, Akt, p38 MAP kinase, and cyclooxygenase-2 (COX-2). LPS induced rapid phosphorylation of NF-kappaB p65, Akt, and p38 MAPK and degradation of Ikappa-Balpha. LPS induced expression of COX-2 and secretion of PGE2 (2.0+/-0.8-fold induction vs. unstimulated cells), IL-6 (6.6+/-0.4-fold induction), and KC (12.5+/-0.4-fold induction). Inhibition of phosphoinositide-3 (PI3)-kinase, p38 MAPK, or NF-kappaB pathways reduced LPS-induced PGE2, IL-6, and KC secretion. These studies show that primary murine intestinal MF respond to LPS, evidenced by activation of NF-kappaB, PI3-kinase, and MAPK signaling pathways and secretion of proinflammatory molecules. Inhibition of these pathways attenuated LPS-dependent PGE2, IL-6, and KC production, indicating that LPS activates MF by multiple signaling pathways. These data support the hypothesis that MF are a component of the innate immune system and may exert paracrine effects on adjacent epithelial and immune cells by responding to luminal bacterial adjuvants.
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Affiliation(s)
- Kristen L. W. Walton
- Department of Medicine and Center for Gastrointestinal Biology, University of North Carolina, Chapel Hill, North Carolina
| | - Lisa Holt
- Department of Medicine and Center for Gastrointestinal Biology, University of North Carolina, Chapel Hill, North Carolina
| | - R. Balfour Sartor
- Department of Medicine and Center for Gastrointestinal Biology, University of North Carolina, Chapel Hill, North Carolina
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Ivanov II, Frutos RDL, Manel N, Yoshinaga K, Rifkin DB, Sartor RB, Finlay BB, Littman DR. Specific microbiota direct the differentiation of IL-17-producing T-helper cells in the mucosa of the small intestine. Cell Host Microbe 2008; 4:337-49. [PMID: 18854238 PMCID: PMC2597589 DOI: 10.1016/j.chom.2008.09.009] [Citation(s) in RCA: 1305] [Impact Index Per Article: 81.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 09/02/2008] [Accepted: 09/17/2008] [Indexed: 11/16/2022]
Abstract
The requirements for in vivo steady state differentiation of IL-17-producing T-helper (Th17) cells, which are potent inflammation effectors, remain obscure. We report that Th17 cell differentiation in the lamina propria (LP) of the small intestine requires specific commensal microbiota and is inhibited by treating mice with selective antibiotics. Mice from different sources had marked differences in their Th17 cell numbers and animals lacking Th17 cells acquired them after introduction of bacteria from Th17 cell-sufficient mice. Differentiation of Th17 cells correlated with the presence of cytophaga-flavobacter-bacteroidetes (CFB) bacteria in the intestine and was independent of toll-like receptor, IL-21 or IL-23 signaling, but required appropriate TGF-beta activation. Absence of Th17 cell-inducing bacteria was accompanied by increase in Foxp3+ regulatory T cells (Treg) in the LP. Our results suggest that composition of intestinal microbiota regulates the Th17:Treg balance in the LP and may thus influence intestinal immunity, tolerance, and susceptibility to inflammatory bowel diseases.
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Affiliation(s)
- Ivaylo I Ivanov
- Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
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Abstract
BACKGROUND Commensal enteric microbiota initiate and perpetuate immune-mediated colitis in HLA-B27 transgenic (TG) rats but not wildtype (non-TG) littermates. However, the role of the innate immune response to bacterial components has not been established. METHODS We examined responses induced by bacterial adjuvants through Toll-like receptor (TLR) and NOD2 signaling in T-cell-depleted splenocytes from HLA-B27 TG rats versus non-TG controls. RESULTS We found that various bacterial adjuvants induced TNF production by cells obtained from specific pathogen-free (SPF) and germ-free (GF, sterile) TG and non-TG rats. Peptidoglycan-polysaccharide (PG-PS), lipopolysaccharide (LPS), and CpG DNA motifs stimulated higher levels of TNF production by SPF TG rat spleen cells compared to non-TG cells. CD11b/c cell depletion eliminated PG-PS and LPS-induced TNF and dramatically reduced CpG-stimulated TNF production. Both SPF and GF TG rat spleens contain more cells that express high levels of CD11b/c and show enhanced mRNA expression of TLR-2 and TLR-4 compared to non-TG rat spleens. In contrast, constitutive and bacterial-induced IL-10 production was markedly lower in TG cells compared to non-TG cells of rats from the same SPF or GF housing conditions. Notably, the ratio of TNF to IL-10 produced after TLR ligand activation was significantly higher in TG than non-TG cells. CONCLUSIONS HLA-B27 TG rats have an aberrant cell composition, altered functional TLR expression, and an intrinsic defect in IL-10 production in response to TLR ligands, which may result in exaggerated proinflammatory responses to commensal enteric bacteria and uncontrolled inflammation in this colitis model.
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Affiliation(s)
- Bi-Feng Qian
- Center for Gastrointestinal Biology and Disease, University of North Carolina, Chapel Hill, NC 27599, USA
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112
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Purohit V, Bode JC, Bode C, Brenner DA, Choudhry MA, Hamilton F, Kang YJ, Keshavarzian A, Rao R, Sartor RB, Swanson C, Turner JR. Alcohol, intestinal bacterial growth, intestinal permeability to endotoxin, and medical consequences: summary of a symposium. Alcohol 2008; 42:349-61. [PMID: 18504085 DOI: 10.1016/j.alcohol.2008.03.131] [Citation(s) in RCA: 232] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 03/11/2008] [Accepted: 03/27/2008] [Indexed: 12/13/2022]
Abstract
This report is a summary of the symposium on Alcohol, Intestinal Bacterial Growth, Intestinal Permeability to Endotoxin, and Medical Consequences, organized by National Institute on Alcohol Abuse and Alcoholism, Office of Dietary Supplements, and National Institute of Diabetes and Digestive and Kidney Diseases of National Institutes of Health in Rockville, Maryland, October 11, 2006. Alcohol exposure can promote the growth of Gram-negative bacteria in the intestine, which may result in accumulation of endotoxin. In addition, alcohol metabolism by Gram-negative bacteria and intestinal epithelial cells can result in accumulation of acetaldehyde, which in turn can increase intestinal permeability to endotoxin by increasing tyrosine phosphorylation of tight junction and adherens junction proteins. Alcohol-induced generation of nitric oxide may also contribute to increased permeability to endotoxin by reacting with tubulin, which may cause damage to microtubule cytoskeleton and subsequent disruption of intestinal barrier function. Increased intestinal permeability can lead to increased transfer of endotoxin from the intestine to the liver and general circulation where endotoxin may trigger inflammatory changes in the liver and other organs. Alcohol may also increase intestinal permeability to peptidoglycan, which can initiate inflammatory response in liver and other organs. In addition, acute alcohol exposure may potentiate the effect of burn injury on intestinal bacterial growth and permeability. Decreasing the number of Gram-negative bacteria in the intestine can result in decreased production of endotoxin as well as acetaldehyde which is expected to decrease intestinal permeability to endotoxin. In addition, intestinal permeability may be preserved by administering epidermal growth factor, l-glutamine, oats supplementation, or zinc, thereby preventing the transfer of endotoxin to the general circulation. Thus reducing the number of intestinal Gram-negative bacteria and preserving intestinal permeability to endotoxin may attenuate alcoholic liver and other organ injuries.
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Affiliation(s)
- Vishnudutt Purohit
- Division of Metabolism and Health Effects, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5635 Fishers Lane, Room 2035, MSC 9304, Bethesda, MD 20892-9304, USA.
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Qian BF, Tonkonogy SL, Sartor RB. Reduced responsiveness of HLA-B27 transgenic rat cells to TGF-beta and IL-10-mediated regulation of IFN-gamma production. Inflamm Bowel Dis 2008; 14:921-30. [PMID: 18340648 DOI: 10.1002/ibd.20415] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND We have reported that commensal luminal bacterial components induce an active in vitro IFN-gamma response in mesenteric lymph node (MLN) and intestinal cells from specific pathogen-free (SPF) HLA-B27 transgenic (TG) rats with chronic colitis but not in cells from non-diseased SPF non-TG, germ-free (GF) non-TG or GF TG rats. METHODS The study examined IL-12 stimulation of MLN IFN-gamma responses to luminal bacteria and regulation of these responses by suppressive cytokines. RESULTS Exogenous IL-12 significantly increased the bacterial lysate-induced IFN-gamma response in SPF TG MLN cells, while bacterial lysate and IL-12 synergistically induced IFN-gamma from low baseline levels in cells obtained from both SPF and GF non-TG rats, and in GF TG cells. TGF-beta fully counteracted the effects of IL-12 and bacterial lysate on non-TG cells by almost completely inhibiting IFN-gamma production. In contrast, TG cells were less responsive to TGF-beta-mediated downregulation with a substantial residual IFN-gamma response to IL-12 plus bacterial lysate. Further experiments showed that CD4+/CD25+ cells had no inhibitory effect on the IFN-gamma production and were not required for TGF-beta-mediated suppression. Addition of exogenous IL-10 also partially inhibited IFN-gamma production by non-TG cells but did not affect TG cells. Conversely, exogenous IL-12 preferentially suppressed bacterial lysate-induced TGF-beta and IL-10 production in TG rat cells. CONCLUSIONS An attenuated response to regulatory signals leads to uncontrolled potentiated induction of effector IFN-gamma responses to commensal bacteria in HLA-B27 TG rats that spontaneously develop chronic intestinal inflammation.
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Affiliation(s)
- Bi-Feng Qian
- Center for Gastrointestinal Biology and Disease, Department of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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114
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Packey CD, Sartor RB. Interplay of commensal and pathogenic bacteria, genetic mutations, and immunoregulatory defects in the pathogenesis of inflammatory bowel diseases. J Intern Med 2008; 263:597-606. [PMID: 18479259 DOI: 10.1111/j.1365-2796.2008.01962.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Enteric microbiota can contribute to Crohn's disease and ulcerative colitis in several ways. Pathogenic or functionally altered commensal bacteria with increased mucosal adherence, invasion and intracellular persistence can activate pathogenic T cells and chronic intestinal inflammation. Compositional changes in intestinal microbiota can lead to decreased protective and increased aggressive species. Genetic polymorphisms resulting in increased mucosal permeability, decreased microbial killing, ineffective clearance of bacteria, biased TH1 and TH17 immune responses and loss of immunological tolerance are probably key contributors to IBD. Future therapies for these heterogeneous diseases should be individualized based on the patient-specific subset.
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Affiliation(s)
- C D Packey
- Department of Medicine, Program of Digestive Health, Unviersity of North Carolina at Chapel Hill, Chapell Hill, NC 27599-7032, USA
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115
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Velázquez P, Wei B, McPherson M, Mendoza LMA, Nguyen SL, Turovskaya O, Kronenberg M, Huang TT, Schrage M, Lobato LN, Fujiwara D, Brewer S, Arditi M, Cheng G, Sartor RB, Newberry RD, Braun J. Villous B cells of the small intestine are specialized for invariant NK T cell dependence. J Immunol 2008; 180:4629-38. [PMID: 18354186 DOI: 10.4049/jimmunol.180.7.4629] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
B cells are important in mucosal microbial homeostasis through their well-known role in secretory IgA production and their emerging role in mucosal immunoregulation. Several specialized intraintestinal B cell compartments have been characterized, but the nature of conventional B cells in the lamina propria is poorly understood. In this study, we identify a B cell population predominantly composed of surface IgM(+) IgD(+) cells residing in villi of the small intestine and superficial lamina propria of the large intestine, but distinct from the intraepithelial compartment or organized intestinal lymphoid structures. Small intestinal (villous) B cells are diminished in genotypes that alter the strength of BCR signaling (Bruton tyrosine kinase(xid), Galphai2(-/-)), and in mice lacking cognate BCR specificity. They are not dependent on enteric microbial sensing, because they are abundant in mice that are germfree or genetically deficient in TLR signaling. However, villous B cells are reduced in the absence of invariant NK T cells (Jalpha18(-/-) or CD1d(-/-) mice). These findings define a distinct population of conventional B cells in small intestinal villi, and suggest an immunologic link between CD1-restricted invariant NK T cells and this B cell population.
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Affiliation(s)
- Peter Velázquez
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, CA 90095, USA
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116
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Abstract
Crohn's disease (CD), ulcerative colitis (UC), and pouchitis appear to be caused by pathogenic T-cell responses to discrete antigens from the complex luminal microbiota, with susceptibility conferred by genetic polymorphisms that regulate bacterial killing, mucosal barrier function, or immune responses. Environmental triggers initiate or reactivate inflammation and modulate genetic susceptibility. New pathogenesis concepts include defective bacterial killing by innate immune cells in CD, colonization of the ileum in CD with functionally abnormal Escherichia coli that adhere to and invade epithelial cells and resist bacterial killing, and alterations in enteric microbiota composition in CD, UC, and pouchitis detected by molecular probes. The considerable therapeutic potential of manipulating the enteric microbiota in inflammatory bowel disease patients has not been realized, probably due to failure to recognize heterogenic disease mechanisms that require individualized use of antibiotics, probiotics, prebiotics, combination therapies, and genetically engineered bacteria to restore mucosal homeostasis.
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Affiliation(s)
- R Balfour Sartor
- Department of Medicine, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, CB #7032, Room 7309, Medical Biomolecular Research Building, Chapel Hill, NC 27599, USA.
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117
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Affiliation(s)
- Nicholas J Shaheen
- Division of Gastroenterology and Hepatology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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118
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Uno JK, Rao K, Matsuoka K, Li F, Sartor RB, Plevy SE. Altered innate immunity contributes to the development of colitis in PI3K p110d mutant mice. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.852.1] [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)
| | - Kavitha Rao
- University of North Carolina at Chapel HillChapel HillNC
| | | | - Fengling Li
- University of North Carolina at Chapel HillChapel HillNC
| | | | - Scott E Plevy
- University of North Carolina at Chapel HillChapel HillNC
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119
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Abstract
The predominantly anaerobic microbiota of the distal ileum and colon contain an extraordinarily complex variety of metabolically active bacteria and fungi that intimately interact with the host's epithelial cells and mucosal immune system. Crohn's disease, ulcerative colitis, and pouchitis are the result of continuous microbial antigenic stimulation of pathogenic immune responses as a consequence of host genetic defects in mucosal barrier function, innate bacterial killing, or immunoregulation. Altered microbial composition and function in inflammatory bowel diseases result in increased immune stimulation, epithelial dysfunction, or enhanced mucosal permeability. Although traditional pathogens probably are not responsible for these disorders, increased virulence of commensal bacterial species, particularly Escherichia coli, enhance their mucosal attachment, invasion, and intracellular persistence, thereby stimulating pathogenic immune responses. Host genetic polymorphisms most likely interact with functional bacterial changes to stimulate aggressive immune responses that lead to chronic tissue injury. Identification of these host and microbial alterations in individual patients should lead to selective targeted interventions that correct underlying abnormalities and induce sustained and predictable therapeutic responses.
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Affiliation(s)
- R Balfour Sartor
- Department of Medicine, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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120
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Kim SC, Tonkonogy SL, Karrasch T, Jobin C, Sartor RB. Dual-association of gnotobiotic IL-10-/- mice with 2 nonpathogenic commensal bacteria induces aggressive pancolitis. Inflamm Bowel Dis 2007; 13:1457-66. [PMID: 17763473 DOI: 10.1002/ibd.20246] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Monoassociating gnotobiotic IL-10-deficient (-/-) mice with either nonpathogenic Enterococcus faecalis or a nonpathogenic Escherichia coli strain induces T-cell-mediated colitis with different kinetics and anatomical location (E. faecalis: late onset, distal colonic; E. coli: early onset, cecal). HYPOTHESIS E. faecalis and E. coli act in an additive manner to induce more aggressive colitis than disease induced by each bacterial species independently. METHODS Germ-free (GF) inbred 129S6/SvEv IL-10-/- and wildtype (WT) mice inoculated with nonpathogenic E. faecalis and/or E. coli were killed 3-7 weeks later. Colonic segments were scored histologically for inflammation (0 to 4) or incubated in media overnight to measure spontaneous IL-12/IL-23p40 secretion. Bacterial species were quantified by serial dilution and plated on culture media. Mesenteric lymph node (MLN) CD4(+) cells were stimulated with antigen-presenting cells pulsed with bacterial lysate (E. faecalis, E. coli, Bacteroides vulgatus) or KLH (unrelated antigen control). IFN-gamma and IL-17 levels were measured in the supernatants. RESULTS Dual-associated IL-10-/- (but not WT) mice developed mild-to-moderate pancolitis by 3 weeks that progressed to severe distal colonic-predominant pancolitis with reactive atypia and duodenal inflammation by 7 weeks. NF-kappaB was activated in the duodenum and colon in dual-associated IL-10-/- x NF-kappaB(EGFP) mice. The aggressiveness of intestinal inflammation and the degree of antigen-specific CD4(+) cell activation were greater in dual- versus monoassociated IL-10-/- mice. CONCLUSION Two commensal bacteria that individually induce phenotypically distinct colitis in gnotobiotic IL-10-/- mice act additively to induce aggressive pancolitis and duodenal inflammation.
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Affiliation(s)
- Sandra C Kim
- Center for Gastrointestinal Biology and Disease, University of North Carolina, Chapel Hill, NC, USA.
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121
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Meng D, Newburg DS, Young C, Baker A, Tonkonogy SL, Sartor RB, Walker WA, Nanthakumar NN. Bacterial symbionts induce a FUT2-dependent fucosylated niche on colonic epithelium via ERK and JNK signaling. Am J Physiol Gastrointest Liver Physiol 2007; 293:G780-7. [PMID: 17673542 DOI: 10.1152/ajpgi.00010.2007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The intestinal epithelium of the adult gut supports a complex, dynamic microbial ecosystem and expresses highly fucosylated glycans on its surface. Uncolonized gut contains little fucosylated glycan. The transition toward adult colonization, such as during recovery from germ-free status or from antibiotic treatment, increased expression of fucosylated epitopes in the colonic epithelium. This increase in fucosylation is accompanied by induction of fut2 mRNA expression and alpha1,2/3-fucosyltransferase activity. Colonization stimulates ERK and JNK signal transduction pathways, resulting in activation of transcription factors ATF2 and c-Jun, respectively. This increases transcription of fut2 mRNA and expression of alpha1,2/3-fucosyltransferase activity, resulting in a highly fucosylated intestinal mucosa characteristic of the adult mammalian gut. Blocking the ERK and JNK signaling cascade inhibits the ability of colonization to induce elevated fut2 mRNA and fucosyltransferase activity in the mature colon. Thus pioneer-mutualist symbiotic bacteria may utilize the ERK and JNK signaling cascade to induce the high degree of fucosylation characteristic of adult mammalian colon, and we speculate that this fucosylation facilitates colonization by adult microbiota.
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Affiliation(s)
- Di Meng
- Developmental Gastroenterology Laboratory, Massachusetts General Hospital-East, 114 16th St., Rm 3650, Charlestown, MA 02129, USA
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122
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Abstract
This article provides a summary of the proceedings of the CCFA Microbial-Host Interactions Workshop that was held in St. Petersburg, Florida, on March 16-19, 2006. Approximately 75 senior and junior investigators from around the world shared their most current research findings through oral presentations, poster sessions, and active discussion. Because intestinal microbiota are significant contributors in the development of inflammatory bowel diseases (IBD), understanding the body's responses to and interactions with microbes, especially in the colon and distal small intestine, is critical to elucidating the etiology and pathogenesis of IBD and developing effective therapeutic interventions. Major advances have occurred recently in molecular detection of luminal bacterial species, identifying dominant microbial antigens that drive intestinal inflammation, the mechanisms of innate immune and epithelial responses to bacteria, and regulation of inflammation by innate and acquired immune cells.
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Affiliation(s)
- R Balfour Sartor
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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123
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Abstract
Microbial agents are implicated in each of the most prevalent etiologic hypotheses of Crohn's disease. Although chronic infection with a specific, persistent pathogen cannot be excluded, it is more likely that Crohn's disease is caused by an overly aggressive immune response to normal commensal enteric bacteria. The complex, predominantly anaerobic microbiota in the distal ileum and colon provide a constant source of antigens and adjuvants that stimulate chronic immune-mediated inflammation in genetically susceptible hosts. Host genetic susceptibility in the form of defective mucosal barrier function, bacterial killing or processing can lead to enhanced exposure to luminal bacteria and their immunologically active components, whereas defective immunoregulation can lead to lack of appropriate immunosuppression. Either process can lead to overly aggressive T-cell responses to normal bacteria that causes tissue damage. Transient infection with pathogenic organisms could serve as environmental triggers to initiate inflammatory responses that are perpetuated in susceptible hosts by commensal microbial antigens. In addition, commensal bacteria such as Escherichia coli recovered from the ileum of patients with recurrent Crohn's disease after resection can contain virulence factors that mediate epithelial attachment, invasion, and resistance to killing. Finally, Western diet, antibiotic use, hygiene, and public health practices may have altered the balance of beneficial versus aggressive microbial species. Crohn's disease patients exhibit enhanced humoral and T-cell responses to common commensal bacterial and fungal antigens. These observations may help identify clinically relevant patient subsets and suggest novel therapeutic approaches to restore a beneficial balance of enteric microbiota, enhanced microbial killing, and inhibit aggressive T-cell responses to microbial antigens.
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Affiliation(s)
- R Balfour Sartor
- Department of Medicine, Division of Gastroenterology and Hepatology, University of North Carolina, Chapel Hill, NC 27599, USA.
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124
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Hoentjen F, Tonkonogy SL, Qian BF, Liu B, Dieleman LA, Sartor RB. CD4(+) T lymphocytes mediate colitis in HLA-B27 transgenic rats monoassociated with nonpathogenic Bacteroides vulgatus. Inflamm Bowel Dis 2007; 13:317-24. [PMID: 17206701 DOI: 10.1002/ibd.20040] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND HLA-B27/beta2 microglobulin transgenic (TG) rats develop spontaneous colitis when raised under specific pathogen-free (SPF) conditions or after mono-association with Bacteroides vulgatus (B. vulgatus), whereas germ-free TG rats fail to develop intestinal inflammation. SPF HLA-B27 TG rnu/rnu rats, which are congenitally athymic, remain disease free. These results indicate that commensal intestinal bacteria and T cells are both pivotal for the development of colitis in TG rats. However, it is not known if T cells are also required in the induction of colitis by a single bacterial strain. The aim of this study was therefore to investigate the role of T cells in the development of colitis in B. vulgatus-monoassociated HLA-B27 TG rats. METHODS HLA-B27 TG rnu/rnu and rnu/+ rats were monoassociated with B. vulgatus for 8-12 weeks. CD4(+) T cells from mesenteric lymph nodes (MLNs) of B. vulgatus-monoassociated rnu/+ TG donor rats were transferred into B. vulgatus-monoassociated rnu/rnu TG recipients. RESULTS B. vulgatus-monoassociated rnu/+ rats showed higher histologic inflammatory scores and elevated colonic interferon-gamma mRNA, cecal myeloperoxidase, and cecal IL-1beta levels compared to those in rnu/rnu TG rats that did not contain T cells. After transfer of CD4(+) cells from colitic B. vulgatus-monoassociated rnu/+ TG donor rats, B. vulgatus-monoassociated rnu/rnu TG recipients developed colitis that was accompanied by B. vulgatus-induced IFN-gamma production by MLN cells in vitro and inflammatory parameters similar to rnu/+ TG rats. CONCLUSIONS These results implicate CD4(+) T cells in the development of colitis in HLA-B27 TG rats monoassociated with the nonpathogenic bacterial strain B. vulgatus.
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Affiliation(s)
- Frank Hoentjen
- Division of Gastroenterology and Hepatology, University of North Carolina, Chapel Hill, North Carolina, USA
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125
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Hassan S, Sainz IM, Khan MM, Bradford HN, Isordia-Salas I, Kashem SW, Sartor RB, Colman RW. Antithrombotic activity of kininogen is mediated by inhibitory effects of domain 3 during arterial injury in vivo. Am J Physiol Heart Circ Physiol 2007; 292:H2959-65. [PMID: 17293494 DOI: 10.1152/ajpheart.00730.2006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High-molecular-weight kininogen (HK) and its domain 3 (D3) exhibit anticoagulant properties and inhibit platelet activation at low thrombin concentration in vitro. We hypothesized that the rapid occlusive thrombosis in HK-deficient (HKd) rats following endothelial injury of the aorta results from enhanced platelet aggregation by thrombin. The effects of D3 (G235-M357) or D3-derived peptides on thrombosis in vivo were tested. D3 and its exon 7C terminal peptide (E7CP, K270-Q292), expressed as glutathione S-transferase (GST) fusion proteins (GST-D3, GST-E7CP), or GST alone, as well as cleaved HK (HKa) or synthetic peptide E7CP, were infused intravenously 10 min before endothelial injury. Blood flow was reduced down to 10% of baseline flow within 28 +/- 5.2 min by a platelet-fibrin thrombus in GST-treated HKd rats compared with >240 min in GST-treated normal HK rats (wild type). GST-D3, GST-E7CP, HKa, or E7CP infusion prolonged the flow time to 233, >240, 223, and >240 min, respectively, in HKd rats. When GST-E7CP was infused 10 min after the injury, blood flow was maintained for >240 min. Thrombin-antithrombin concentrations were elevated by injury in HKd rats receiving GST from 35 to 55 microg/l and decreased with GST-E7CP, HKa, or E7CP reconstitution to 40, 15, and 9 microg/l, respectively. We conclude that HKd rats are prothrombotic and that HKa, kininogen D3, and its fragment E7CP modulate arterial thrombosis after endothelial injury.
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MESH Headings
- Amino Acid Sequence
- Animals
- Animals, Genetically Modified
- Antithrombin III
- Aorta/drug effects
- Aorta/injuries
- Aorta/metabolism
- Aorta/pathology
- Aorta/physiopathology
- Blood Flow Velocity
- Disease Models, Animal
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/injuries
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/pathology
- Endothelium, Vascular/physiopathology
- Fibrin/metabolism
- Fibrinolytic Agents/chemistry
- Fibrinolytic Agents/metabolism
- Fibrinolytic Agents/pharmacology
- Fibrinolytic Agents/therapeutic use
- Glutathione Transferase/genetics
- Kininogen, High-Molecular-Weight/chemistry
- Kininogen, High-Molecular-Weight/genetics
- Kininogen, High-Molecular-Weight/metabolism
- Kininogen, High-Molecular-Weight/pharmacology
- Kininogen, High-Molecular-Weight/therapeutic use
- Male
- Molecular Sequence Data
- Peptide Fragments/genetics
- Peptide Fragments/metabolism
- Peptide Fragments/pharmacology
- Peptide Hydrolases/blood
- Platelet Aggregation
- Protein Structure, Tertiary
- Rats
- Rats, Inbred Lew/genetics
- Recombinant Fusion Proteins/metabolism
- Regional Blood Flow
- Thrombin/metabolism
- Thrombosis/metabolism
- Thrombosis/pathology
- Thrombosis/physiopathology
- Thrombosis/prevention & control
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Affiliation(s)
- Sarmina Hassan
- Sol Sherry Thrombosis Research Center, Temple Univeristy School of Medicine, 3400 N. Broad St., Rm. 418 OMS, Philadelphia, PA 19140, USA
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126
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Shkoda A, Ruiz PA, Daniel H, Kim SC, Rogler G, Sartor RB, Haller D. Interleukin-10 blocked endoplasmic reticulum stress in intestinal epithelial cells: impact on chronic inflammation. Gastroenterology 2007; 132:190-207. [PMID: 17241871 DOI: 10.1053/j.gastro.2006.10.030] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Accepted: 10/05/2006] [Indexed: 12/31/2022]
Abstract
BACKGROUND & AIMS The initiation of endoplasmic reticulum (ER)-mediated stress responses in intestinal epithelial cells (IEC) may contribute to the pathogenesis of chronic intestinal inflammation. The aim of the study was to use functional epithelial cell proteomics to characterize anti-inflammatory mechanisms of interleukin 10 (IL-10). METHODS Primary IEC were isolated from Enterococcus faecalis-monoassociated IL-10-deficient (IL-10-/-) and wild-type mice to perform 2D-gel sodium-dodecyl-sulfate polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight mass spectrometry. In addition, IEC from 6 patients with active Crohn's disease, ulcerative colitis, and sigmoid diverticulitis as well as noninflamed controls were purified. Molecular protective mechanisms of IL-10 were characterized in tumor necrosis factor (TNF)-stimulated IL-10 receptor (IL-10R) reconstituted epithelial cells. RESULTS Primary IEC from IL-10-/- mice as well as inflammatory bowel disease patients revealed increased expression levels of the glucose-regulated ER stress protein (grp)-78 under conditions of chronic inflammation. Consistent with the observation that TNF induced ER stress responses through grp-78 redistribution from the ER lumen to the cytoplasmic IkappaB kinase complex, grp-78 knockdown completely abolished TNF-induced nuclear factor-kappaB RelA phosphorylation in epithelial cell cultures. Interestingly, IL-10 inhibited grp-78 protein and messenger RNA expression in IL-10R reconstituted IEC. Chromatin immunoprecipitation analysis and immunofluorescence microscopy revealed that IL-10-mediated p38 signaling inhibited TNF-induced recruitment of the ER-derived activating transcription factor (ATF)-6 to the grp-78 promoter likely through the blockade of ATF-6 nuclear translocation. CONCLUSIONS Primary IEC from inflamed IL-10-/- mice and inflammatory bowel disease patients revealed activated ER stress responses in the intestinal epithelium. IL-10 inhibits inflammation-induced ER stress response mechanisms by modulating ATF-6 nuclear recruitment to the grp-78 gene promoter.
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Affiliation(s)
- Anna Shkoda
- Else-Kroener-Fresenius Center for Experimental Nutritional Medicine, Technical University of Munich, 85350 Freising-Weihenstephan, Germany
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127
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Ruiz PA, Shkoda A, Kim SC, Sartor RB, Haller D. IL-10 gene-deficient mice lack TGF-beta/Smad-mediated TLR2 degradation and fail to inhibit proinflammatory gene expression in intestinal epithelial cells under conditions of chronic inflammation. Ann N Y Acad Sci 2006; 1072:389-94. [PMID: 17057220 DOI: 10.1196/annals.1326.023] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Nonpathogenic enteric bacterial species initiate and perpetuate experimental colitis in interleukin-10 geneeficient mice (IL-10(-/-)). Bacteria-specific effects on the epithelium are difficult to distinguish because of the complex nature of the gut microflora. We showed that IL-10(-/-) mice compared to wild-type mice fail to inhibit pro-inflammatory gene expression in native intestinal epithelial cells after the colonization with colitogenic Gram-positive Enterococcus faecalis. Of interest, pro-inflammatory gene expression was transient after 1 week of E. faecalis monoassociation in IECs from wild-type mice but persisted after 14 weeks of bacterial colonization in IL-10(-/-) mice. Accordingly, wild-type IECs expressed phosphorylated NF-kappaB subunit RelA (p65) and phosphorylated Smad2 only at day 7 after bacterial colonization, whereas E. faecalis-monoassociated IL-10(-/-) mice triggered persistent RelA but no Smad2 phosphorylation in IECs at days 3, 7, 14, and 28. Consistent with the induction of TLR2-mediated RelA phosphorylation and pro-inflammatory gene expression in E. faecalis-stimulated cell lines, TLR2 protein expression was absent after day 7 from E. faecalis-monoassociated wild-type mice but persisted in IL-10(-/-) IECs. Of note, TGF-beta-activated Smad signaling was associated with the loss of TLR2 protein expression and the inhibition of NF-kappa Bependent gene expression in E. faecalis-stimulated IEC lines. In conclusion, E. faecalis-monoassociated IL-10(-/-) but not wild-type mice lack protective TGF-beta/Smad signaling and fail to inhibit TLR2-mediated pro-inflammatory gene expression in the intestinal epithelium, suggesting a critical role for IL-10 and TGF-beta in maintaining normal epithelial cell homeostasis in the interplay with commensal enteric bacteria.
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Affiliation(s)
- Pedro A Ruiz
- Else-Kroener-Fresenius Centre for Experimental Nutritional Medicine, Technical University of Munich, 85350 Freising-Weihenstephan, Germany
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128
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Abstract
Crohn's disease and ulcerative colitis are idiopathic, chronic, relapsing, inflammatory conditions that are immunologically mediated. Although their exact etiologies remain uncertain, results from research in animal models, human genetics, basic science and clinical trials have provided important new insights into the pathogenesis of chronic, immune-mediated, intestinal inflammation. These studies indicate that Crohn's disease and ulcerative colitis are heterogeneous diseases characterized by various genetic abnormalities that lead to overly aggressive T-cell responses to a subset of commensal enteric bacteria. The onset and reactivation of disease are triggered by environmental factors that transiently break the mucosal barrier, stimulate immune responses or alter the balance between beneficial and pathogenic enteric bacteria. Different genetic abnormalities can lead to similar disease phenotypes; these genetic changes can be broadly characterized as causing defects in mucosal barrier function, immunoregulation or bacterial clearance. These new insights will help develop better diagnostic approaches that identify clinically important subsets of patients for whom the natural history of disease and response to treatment are predictable.
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Affiliation(s)
- R Balfour Sartor
- Department of Medicine, University of North Carolina, Chapel Hill, NC 27599-7032, USA.
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129
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Veltkamp C, Ruhwald R, Giesem T, Autschbach F, Kaden I, Veltkamp R, Sartor RB, Stremmel W. CD4+CD25+ cell depletion from the normal CD4+ T cell pool prevents tolerance toward the intestinal flora and leads to chronic colitis in immunodeficient mice. Inflamm Bowel Dis 2006; 12:437-46. [PMID: 16775487 DOI: 10.1097/00054725-200606000-00002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
CD4+CD25+ regulatory T cells have been shown to prevent immune-mediated colitis in mice; however, it is unclear whether the absence of CD4+CD25+ in the normal CD4+ T cell pool is responsible for the development of chronic colitis. Using the T cell-deficient Tgepsilon26 mouse model, we show that CD4+CD25- cells but not CD4+CD25+ cells induce a severe intestinal inflammation. Transfer of CD4+CD25+ cells, together with CD4+CD25- cells, ameliorated intestinal inflammation, and reconstitution with the whole mesenteric lymph node cell pool did not induce colitis in recipients. Transferred CD4+CD25- cells were found mainly in the mesenteric lymph nodes, where they showed an activated TH1-like phenotype. In the absence of regulatory CD4+CD25+ T cells, recipient CD4 cells secreted IFN-gamma in response to stimulation with intestinal bacterial antigen that was prevented in vivo and in vitro by regulatory CD4+CD25+ cells. These studies suggest that CD4+CD25- cells have a strong colitogenic effect in the Tgepsilon26 colitis model and that CD4+CD25+ cells may be the main regulators that prevent or downregulate the proinflammatory effect of colitogenic T cells in the Tgepsilon26 mouse model.
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Affiliation(s)
- Claudia Veltkamp
- Department of Gastroenterology, Ruprecht-Karls-University, Heidelberg, Germany.
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130
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Abstract
Commensal enteric bacteria stimulate innate immune cells and increase numbers of lamina propria and mesenteric lymph node (MLN) T and B lymphocytes. However, the influence of luminal bacteria on acquired immune function is not understood fully. We investigated the effects of intestinal bacterial colonization on T cell tolerogenic responses to oral antigen compared to systemic immunization. Lymphocytes specific for ovalbumin-T cell receptor (OVA-TCR Tg(+)) were transplanted into germ-free (GF) or specific pathogen-free (SPF) BALB/c mice. Recipient mice were fed OVA or immunized subcutaneously with OVA peptide (323-339) in complete Freund's adjuvant (CFA). Although the efficiency of transfer was less in GF recipients, similar proportions of cells from draining peripheral lymph node (LN) or MLN were proliferating 3-4 days later in vivo in GF and SPF mice. In separate experiments, mice were fed tolerogenic doses of OVA and then challenged with an immunogenic dose of OVA 4 days later. Ten days after immunization, lymphocytes were restimulated with OVA in vitro to assess antigen-specific proliferative responses. At both high and low doses of OVA, cells from both SPF and GF mice fed OVA prior to immunization had decreased proliferation compared to cells from control SPF or GF mice. In addition, secretion of interferon (IFN)-gamma and interleukin (IL)-10 by OVA-TCR Tg(+) lymphocytes was reduced in both SPF and GF mice fed OVA compared to control SPF or GF mice. Unlike previous reports indicating defective humoral responses to oral antigen in GF mice, our results indicate that commensal enteric bacteria do not enhance the induction of acquired, antigen-specific T cell tolerance to oral OVA.
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Affiliation(s)
- K L W Walton
- Department of Medicine, SPIRE Program, Centre for Gastrointestinal Biology of Disease, Univeristy of North Carolina, Chapel Hill, NC 27599-7032, USA.
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Qian BF, Tonkonogy SL, Balfour Sartor R. Luminal bacterial antigen-specific CD4+ T-cell responses in HLA-B27 transgenic rats with chronic colitis are mediated by both major histocompatibility class II and HLA-B27 molecules. Immunology 2006; 117:319-28. [PMID: 16476051 PMCID: PMC1782237 DOI: 10.1111/j.1365-2567.2005.02303.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Rats transgenic (TG) for the human major histocompatibility complex (MHC) class I HLA-B27 and beta2-microglobulin genes develop chronic colitis under specific pathogen-free (SPF) but not sterile (germ-free, GF) conditions. We investigated the role of antigen-presenting molecules involved in generating immune responses by CD4+ mesenteric lymph node (MLN) cells from colitic HLA-B27 TG rats to commensal enteric micro-organisms. All TG MLN cells expressed HLA-B27. A higher level of MHC class II was expressed on cells from TG rats, both SPF and GF, compared to non-TG littermates. In contrast, rat MHC class I expression was lower on TG than non-TG cells. Both TG and non-TG antigen presenting cells (APC) pulsed with caecal bacterial antigens induced a marked interferon-gamma (IFN-gamma) response in TG CD4+ T lymphocytes but failed to stimulate non-TG cells. Blocking MHC class II on both TG and non-TG APC dramatically inhibited their ability to induce TG CD4+ T cells to produce IFN-gamma. Blocking HLA-B27 on TG APC similarly inhibited IFN-gamma responses. When the antibodies against MHC class II and HLA-B27 were combined, no APC-dependent IFN-gamma response was detected. These data implicate both native rat MHC class II and TG HLA-B27 in CD4+ MLN T-cell IFN-gamma responses to commensal enteric microflora in this colitis model.
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Affiliation(s)
- Bi-Feng Qian
- Center for Gastrointestinal Biology and Disease, Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
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Hoentjen F, Tonkonogy SL, Liu B, Sartor RB, Taurog JD, Dieleman LA. Adoptive transfer of nontransgenic mesenteric lymph node cells induces colitis in athymic HLA-B27 transgenic nude rats. Clin Exp Immunol 2006; 143:474-83. [PMID: 16487247 PMCID: PMC1809603 DOI: 10.1111/j.1365-2249.2006.03013.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
HLA-B27 transgenic (TG) rats develop spontaneous colitis when colonized with intestinal bacteria, whereas athymic nude (rnu/rnu) HLA-B27 TG rats remain disease free. The present study was designed to determine whether or not HLA-B27 expression on T cells is required for development of colitis after transfer of mesenteric lymph node (MLN) cells into rnu/rnu HLA-B27 recipients. Athymic nontransgenic (non-TG) and HLA-B27 TG recipients received MLN cells from either TG or non-TG rnu/+ heterozygous donor rats that contain T cells. HLA-B27 TG rnu/rnu recipients receiving either non-TG or TG MLN cells developed severe colitis and had higher caecal MPO and IL-1beta levels, and their MLN cells produced more IFN-gamma and less IL-10 after in vitro stimulation with caecal bacterial lysate compared to rnu/rnu non-TG recipients that remained disease free after receiving either TG or non-TG cells. Interestingly, proliferating donor TG T cells were detectable one week after adoptive transfer into rnu/rnu TG recipients but not after transfer into non-TG recipients. T cells from either non-TG or TG donors induce colitis in rnu/rnu TG but not in non-TG rats, suggesting that activation of effector T cells by other cell types that express HLA-B27 is pivotal for the pathogenesis of colitis in this model.
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Affiliation(s)
- F Hoentjen
- Center for Gastrointestinal Biology and Disease, University of North Carolina, Chapel Hill, NC, USA
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Walton KLW, Collins L, Sartor RB. Lipopolysaccharide activates innate immune responses in murine intestinal myofibroblasts. FASEB J 2006. [DOI: 10.1096/fasebj.20.5.a1465-c] [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)
| | | | - R Balfour Sartor
- Medicine
- Center for Gastrointestinal Biology and DiseaseUniversity of North Carolina7317 MBRB, CB#7032Chapel HillNC27599‐7032
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Walton KLW, He J, Kelsall BL, Sartor RB, Fisher NC. Dendritic cells in germ-free and specific pathogen-free mice have similar phenotypes and in vitro antigen presenting function. Immunol Lett 2006; 102:16-24. [PMID: 16105690 DOI: 10.1016/j.imlet.2005.07.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Accepted: 06/16/2005] [Indexed: 11/25/2022]
Abstract
Dendritic cells (DC) can direct downstream T-cell responses. Although bacterial adjuvants are strong activators of DC in vitro, the effects of normal enteric bacteria on DC in vivo are not well defined. We used germ-free (GF) mice to determine whether enteric bacteria alter DC phenotype and ability to stimulate naïve T cells. Surface expression of CD11c, CD86, and MHCII was measured on splenic and mesenteric lymph node (MLN) DC. In addition, we tested the ability of T-cell depleted splenocytes from mice injected with LPS to stimulate allogeneic T cells, as determined by cell proliferation. The absolute numbers of CD11c+ DC were decreased in the MLN and spleen of GF mice. Freshly isolated CD11c+ DC from spleens or MLN of SPF and GF mice expressed similar levels of CD86 and MHCII by FACS analysis. Proportions of splenic DC expressing CD4 or CD8 were not different in GF versus SPF mice, although the percentage of CD8alpha-/CD11b+ DC was higher in GF MLN. Intraperitoneal injection of LPS upregulated MHCII and CD86 to a similar extent on splenic DC from GF or SPF mice. Splenic antigen-presenting cells, as well as unseparated spleen or MLN cells, from GF or SPF mice also induced similar levels of T-cell proliferation in vitro. We conclude that commensal bacterial flora do not affect co-stimulatory molecule expression of DC in the spleen or MLN, which exhibit a predominantly immature phenotype. In addition, splenic APC from GF mice are fully competent to stimulate naïve T-cell proliferation in vitro.
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Affiliation(s)
- Kristen L W Walton
- Department of Medicine, CB#7032, 7317 MBRB, University of North Carolina, Chapel Hill, NC 27599-7032, USA.
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135
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Sartor RB. Microbial and Dietary Factors in the Pathogenesis of Chronic, Immune-Mediated Intestinal Inflammation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 579:35-54. [PMID: 16620011 DOI: 10.1007/0-387-33778-4_4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- R Balfour Sartor
- Division of Gastroenterology and Hepatology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
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Qian BF, Tonkonogy SL, Hoentjen F, Dieleman LA, Sartor RB. Dysregulated luminal bacterial antigen-specific T-cell responses and antigen-presenting cell function in HLA-B27 transgenic rats with chronic colitis. Immunology 2005; 116:112-21. [PMID: 16108823 PMCID: PMC1802408 DOI: 10.1111/j.1365-2567.2005.02206.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
HLA-B27/beta2 microglobulin transgenic (TG) rats spontaneously develop T-cell-mediated colitis when colonized with normal commensal bacteria, but remain disease-free under germ-free conditions. We investigated regulation of in vitro T-cell responses to enteric bacterial components. Bacterial lysates prepared from the caecal contents of specific pathogen-free (SPF) rats stimulated interferon-gamma (IFN-gamma) production by TG but not non-TG mesenteric lymph node (MLN) cells. In contrast, essentially equivalent amounts of interleukin-10 (IL-10) were produced by TG and non-TG cells. However, when cells from MLNs of non-TG rats were cocultured with TG MLN cells, no suppression of IFN-gamma production was noted. Both non-TG and TG antigen-presenting cells (APC) pulsed with caecal bacterial lysate were able to induce IFN-gamma production by TG CD4+ cells, although non-TG APC were more efficient than TG APC. Interestingly, the addition of exogenous IL-10 inhibited non-TG APC but not TG APC stimulation of IFN-gamma production by cocultured TG CD4+ lymphocytes. Conversely, in the presence of exogenous IFN-gamma, production of IL-10 was significantly lower in the supernatants of TG compared to non-TG APC cultures. We conclude that commensal luminal bacterial components induce exaggerated in vitro IFN-gamma responses in HLA-B27 TG T cells, which may in turn inhibit the production of regulatory molecules, such as IL-10. Alterations in the production of IFN-gamma, and in responses to this cytokine, as well as possible resistance of TG cells to suppressive regulation could together contribute to the development of chronic colitis in TG rats.
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Affiliation(s)
- Bi-Feng Qian
- Center for Gastrointestinal Biology and Disease, Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
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Lees C, Howie S, Sartor RB, Satsangi J. The hedgehog signalling pathway in the gastrointestinal tract: implications for development, homeostasis, and disease. Gastroenterology 2005; 129:1696-710. [PMID: 16285967 DOI: 10.1053/j.gastro.2005.05.010] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Accepted: 04/27/2005] [Indexed: 12/21/2022]
Abstract
The hedgehog signalling pathway is critical to normal mammalian gastrointestinal development. Through epithelial-mesenchymal interactions, hedgehog signalling ensures appropriate axial patterning of the embryonic gut. Congenital abnormalities, including malrotations, anorectal malformations, and tracheoesophageal fistula are associated with germ-line mutations/deletion of genes encoding hedgehog signalling components in man and present in genetically engineered animal models. In adults, there is evidence that the pathway plays a role in maintaining stem cell populations in the stomach and directing epithelial cell differentiation in the intestine. Recent data implicate hedgehog signalling in the formation and maintenance of a number of malignancies, including those of the upper gastrointestinal (GI) tract and pancreas, in which abrogation of the pathway offers a novel therapeutic approach in animal models. Most recently, evidence in vitro indicates that there is a recapitulation of embryonic hedgehog signalling in acute epithelial injury and chronic inflammation, a finding with key implications for inflammatory disorders of the intestine, such as inflammatory bowel diseases. This pathway may provide an important link between chronic inflammation and cancer. We summarize the available evidence demonstrating that this developmental pathway has continuing roles in adult homeostasis and is dysregulated in malignancy and inflammation of the gastrointestinal tract.
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Affiliation(s)
- Charlie Lees
- Gastrointestinal Unit, School of Molecular and Clinical Medicine, Western General Hospital, University of Edinburgh, Edinburgh, United Kingdom.
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Sartor RB. Are we losing control? Medical costs can no longer be ignored. Gastroenterology 2005; 129:1149. [PMID: 16230068 DOI: 10.1053/j.gastro.2005.08.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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139
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Sainz IM, Isordia-Salas I, Castaneda JL, Agelan A, Liu B, DeLa Cadena RA, Pixley RA, Adam A, Sartor RB, Colman RW. Modulation of inflammation by kininogen deficiency in a rat model of inflammatory arthritis. ACTA ACUST UNITED AC 2005; 52:2549-52. [PMID: 16059911 DOI: 10.1002/art.21202] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To compare inflammatory peripheral arthritis in wild-type and high molecular weight kininogen (HK)-deficient rats, both on the genetically susceptible Lewis background. METHODS By backcrossing Brown-Norway HK-deficient rats with Lewis rats for 6 generations, 2 new strains were produced, wild-type F6 and HK-deficient F6, each with a 98.5% Lewis genome. Inflammatory arthritis was induced by intraperitoneal injection of peptidoglycan-polysaccharide (PG-PS), and the clinical, histopathologic, and biochemical responses were compared in both strains. RESULTS Eighteen days after PG-PS injection, rats with normal concentrations of HK showed weight loss and marked increase in hind ankle diameter with severe synovial inflammation and cartilage abnormalities. In contrast, HK-deficient rats showed no weight loss (P < 0.05), no increase in hind ankle diameter (P < 0.05), and an absence of inflammatory changes (P < 0.05), as measured by the histologic and morphometric Mankin grading system for synovial and cartilage injury. CONCLUSION Plasma HK is a key mediator of acute and chronic inflammatory arthritis in genetically susceptible Lewis rats.
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140
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Bibiloni R, Fedorak RN, Tannock GW, Madsen KL, Gionchetti P, Campieri M, De Simone C, Sartor RB. VSL#3 probiotic-mixture induces remission in patients with active ulcerative colitis. Am J Gastroenterol 2005; 100:1539-46. [PMID: 15984978 DOI: 10.1111/j.1572-0241.2005.41794.x] [Citation(s) in RCA: 476] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND AIMS Intestinal bacteria have been implicated in the initiation and perpetuation of IBD; in contrast, "probiotic bacteria" have properties possibly effective in treating and preventing relapse of IBD. We evaluated the safety and efficacy of VSL#3 and the components, and the composition of the biopsy-associated microbiota in patients with active mild to moderate ulcerative colitis (UC). METHODS Thirty-four ambulatory patients with active UC received open label VSL#3, 3,600 billion bacteria daily in two divided doses for 6 wk. The presence of biopsy-associated bacteria was detected using a nucleic acid-based method and the presence of VSL#3 species confirmed by DNA sequencing of 16S rRNA. RESULTS Thirty-two patients completed 6 wk of VSL#3 treatment and 2 patients did not have the final endoscopic assessment. Intent to treat analysis demonstrated remission (UCDAI < or = 2) in 53% (n = 18); response (decrease in UCDAI > or = 3, but final score > or =3) in 24% (n = 8); no response in 9% (n = 3); worsening in 9% (n = 3); and failure to complete the final sigmoidoscopy assessment in 5% (n = 2). There were no biochemical or clinical adverse events related to VSL#3. Two of the components of VSL#3 were detected by PCR/DGGE in biopsies collected from 3 patients in remission. CONCLUSION Treatment of patients with mild to moderate UC, not responding to conventional therapy, with VSL#3 resulted in a combined induction of remission/response rate of 77% with no adverse events. At least some of the bacterial species incorporated in the probiotic product reached the target site in amounts that could be detected.
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Affiliation(s)
- Rodrigo Bibiloni
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
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Abstract
BACKGROUND & AIMS Growth hormone (GH) is used to treat growth delay in children with Crohn's disease and in patients with short-bowel syndrome. GH can increase collagen accumulation in intestinal mesenchymal cells, raising concern that GH therapy could exacerbate fibrosis in patients with Crohn's disease. We tested if GH treatment altered inflammation or fibrosis during chronic, experimental granulomatous enterocolitis. METHODS Ileum and cecum of Lewis rats were subserosally injected with peptidoglycan-polysaccharide (PG-APS) or control human serum albumin. At the onset of chronic PG-APS-induced inflammation, rats were administered recombinant human GH or vehicle for 14 days. Fibrosis and inflammation were quantified by gross gut disease scoring, histologic scoring, type I collagen, and cytokine expression in cecum. Abundance and localization of suppressor of cytokine signaling-3 (SOCS-3) messenger RNA and/or protein were determined in cecum. Effect of GH, cytokines, or PG-APS on SOCS-3 synthesis was measured in intestinal myofibroblasts. Myofibroblasts overexpressing SOCS-3 were used to test whether SOCS-3 inhibits collagen accumulation. RESULTS In PG-APS-injected rats, GH modestly reduced gross adhesions and mesenteric contractions, cecal fibrosis score, and collagen expression, but had no effect on intestinal inflammation. GH increased SOCS-3 messenger RNA and protein abundance in PG-APS rats and SOCS-3 messenger RNA was localized to the periphery of granulomas. GH in combination with cytokines or PG-APS, but not alone, induced SOCS-3 synthesis in intestinal myofibroblasts. Myofibroblasts overexpressing SOCS-3 showed reduced cytokine-induced collagen accumulation. CONCLUSIONS GH modestly reduces intestinal fibrosis associated with chronic experimental enterocolitis and stimulates expression of antifibrogenic SOCS-3, suggesting that GH therapy in inflammatory bowel disease should not exacerbate fibrosis.
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Affiliation(s)
- Arianne L Theiss
- Department of Cell and Molecular Pathology, The Univesity of North Carolina at Chapel Hill, 27599-7545, USA
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Abstract
Reassessing this persistent theory in light of advances in molecular microbial detection and genetic pathogenesis of disease.
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Affiliation(s)
- R Balfour Sartor
- UNC Department of Medicine/Division of Gastroenterology and Hepatology, CB #7032, Room 7309 Biomolecular Bldg (MBRB), Chapel Hill, NC 27599-7032, USA.
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Ruiz PA, Shkoda A, Kim SC, Sartor RB, Haller D. IL-10 gene-deficient mice lack TGF-beta/Smad signaling and fail to inhibit proinflammatory gene expression in intestinal epithelial cells after the colonization with colitogenic Enterococcus faecalis. J Immunol 2005; 174:2990-9. [PMID: 15728512 DOI: 10.4049/jimmunol.174.5.2990] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Nonpathogenic enteric bacterial species initiate and perpetuate experimental colitis in IL-10 gene-deficient mice (IL-10(-/-)). Bacteria-specific effects on the epithelium are difficult to dissect due to the complex nature of the gut microflora. We showed that IL-10(-/-) mice compared with wild-type mice fail to inhibit proinflammatory gene expression in native intestinal epithelial cells (IEC) after the colonization with colitogenic Gram-positive Enterococcus faecalis. Interestingly, proinflammatory gene expression was transient after 1 wk of E. faecalis monoassociation in IEC from wild-type mice, but persisted after 14 wk of bacterial colonization in IL-10(-/-) mice. Accordingly, wild-type IEC expressed phosphorylated NF-kappaB subunit RelA (p65) and phosphorylated Smad2 only at day 7 after bacterial colonization, whereas E. faecalis-monoassociated IL-10(-/-) mice triggered persistent RelA, but no Smad2 phosphorylation in IEC at days 3, 7, 14, and 28. Consistent with the induction of TLR2-mediated RelA phosphorylation and proinflammatory gene expression in E. faecalis-stimulated cell lines, TLR2 protein expression was absent after day 7 from E. faecalis-monoassociated wild-type mice, but persisted in IL-10(-/-) IEC. Of note, TGF-beta1-activated Smad signaling was associated with the loss of TLR2 protein expression and the inhibition of NF-kappaB-dependent gene expression in IEC lines. In conclusion, E. faecalis-monoassociated IL-10(-/-), but not wild-type mice lack protective TGF-beta/Smad signaling and fail to inhibit TLR2-mediated proinflammatory gene expression in the intestinal epithelium, suggesting a critical role for IL-10 and TGF-beta in maintaining normal epithelial cell homeostasis in the interplay with commensal enteric bacteria.
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Affiliation(s)
- Pedro A Ruiz
- Centre for Nutrition and Food Research, Immunobiology of Nutrition, Technical University of Munich, Freising-Weihenstephan, Germany
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Kim SC, Tonkonogy SL, Albright CA, Tsang J, Balish EJ, Braun J, Huycke MM, Sartor RB. Variable phenotypes of enterocolitis in interleukin 10-deficient mice monoassociated with two different commensal bacteria. Gastroenterology 2005; 128:891-906. [PMID: 15825073 DOI: 10.1053/j.gastro.2005.02.009] [Citation(s) in RCA: 323] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND & AIMS To explore the hypothesis that selective immune responses to distinct components of the intestinal microflora induce intestinal inflammation, we characterized disease kinetics and bacterial antigen-specific T-cell responses in ex germ-free interleukin 10 -/- and wild-type control mice monoassociated with Enterococcus faecalis , Escherichia coli , or Pseudomonas fluorescens . METHODS Colitis was measured by using blinded histological scores and spontaneous interleukin 12 secretion from colonic strip culture supernatants. Interferon gamma secretion was measured from mesenteric or caudal lymph node CD4 + T cells stimulated with bacterial lysate-pulsed antigen-presenting cells. Luminal bacterial concentrations were measured by culture and quantitative polymerase chain reaction. RESULTS Escherichia coli induced mild cecal inflammation after 3 weeks of monoassociation in interleukin 10 -/- mice. In contrast, Enterococcus faecalis-monoassociated interleukin 10 -/- mice developed distal colitis at 10-12 weeks that was progressively more severe and associated with duodenal inflammation and obstruction by 30 weeks. Neither bacterial strain induced inflammation in wild-type mice, and germ-free and Pseudomonas fluorescens-monoassociated interleukin 10 -/- mice remained disease free. CD4 + T cells from Enterococcus faecalis- or Escherichia coli-monoassociated interleukin 10 -/- mice selectively produced higher levels of interferon gamma and interleukin 4 when stimulated with antigen-presenting cells pulsed with the bacterial species that induced disease; these immune responses preceded the onset of histological inflammation in Enterococcus faecalis -monoassociated mice. Luminal bacterial concentrations did not explain regional differences in inflammation. CONCLUSIONS Different commensal bacterial species selectively initiate immune-mediated intestinal inflammation with distinctly different kinetics and anatomic distribution in the same host.
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Affiliation(s)
- Sandra C Kim
- Center for Gastrointestinal Biology and Disease, University of North Carolina, Chapel Hill, NC 27599-7032, USA
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Sartor RB. Role of commensal enteric bacteria in the pathogenesis of immune-mediated intestinal inflammation: lessons from animal models and implications for translational research. J Pediatr Gastroenterol Nutr 2005; 40 Suppl 1:S30-1. [PMID: 15805841 DOI: 10.1097/00005176-200504001-00018] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
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Veltkamp C, Sartor RB, Giese T, Autschbach F, Kaden I, Veltkamp R, Rost D, Kallinowski B, Stremmel W. Regulatory CD4+CD25+ cells reverse imbalances in the T cell pool of bone marrow transplanted TGepsilon26 mice leading to the prevention of colitis. Gut 2005; 54:207-14. [PMID: 15647183 PMCID: PMC1774840 DOI: 10.1136/gut.2004.046953] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND AND AIMS Erroneous thymic selection of developing T lymphocytes may be responsible for the expansion of self reactive T cells or may contribute to the absence of regulatory T cells important in controlling peripheral inflammatory processes. Colitis in bone marrow (BM) transplanted Tgepsilon26 mice is induced by abnormally activated T cells developing in an aberrant thymic microenvironment. We investigated the protective role of regulatory CD4+CD25+ T cells in this model. METHODS BM from (C57BL/6 x CBA/J) F1 mice was transplanted into specific pathogen free Tgepsilon26 mice (BM-->Tgepsilon26). Transplanted mice received no cells (control), sorted CD4+CD25+, or CD4+CD25- cells from mesenteric lymph nodes (MLN) of normal mice. MLN cell subsets were analysed using membrane markers. Cytokine secretion of MLN cells was measured using intracellular cytokine staining and cytokine secretion in anti-CD3 stimulated cell cultures. Colitis was measured by histological scores. RESULTS CD4+CD25+ cells were reduced in the MLNs of BM-->Tgepsilon26 mice. Transfer of regulatory CD4CD4+CD25+ but not of CD4+CD25- cells reduced the number of MLN CD4+ T cells in BM-->Tgepsilon26 recipients and increased the number of MLN CD8+ cells, thereby normalising the CD4+/CD8+ ratio. CD4+CD25+ but not CD4+CD25- cell transfer into BM-->Tgepsilon26 mice reduced the number of tumour necrosis factor alpha+ CD4+ cells and increased the secretion of transforming growth factor beta by MLN cells. Transfer of 3 x 10(5) CD4+CD25+ cells after BM transplantation into Tgepsilon26 mice prevented colitis whereas CD4+CD25- cells had no protective effect. CONCLUSIONS These results suggest that defective selection or induction of regulatory T cells in the abnormal thymus is responsible for the development of colitis in BM-->Tgepsilon26 mice. Transfer of CD4+CD25+ cells can control intestinal inflammation in BM-->Tgepsilon26 mice by normalising the number and function of the MLN T cell pool.
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Affiliation(s)
- C Veltkamp
- Department of Gastroenterology, University of Heidelberg, INF 410, 69120 Heidelberg, Germany.
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Abd-Alla MD, Abraham SN, Adams D, Anderson DJ, Arntzen CJ, Atkinson TP, Baekkevold ES, Befus AD, Bergmeier LA, Bergsten G, Berin MC, Bernstein JM, Bevins CL, Bienenstock J, Bishop BL, Bjersing J, Blumberg RS, Bobek LA, Boiko N, Bos NA, Bost KL, Boyaka PN, Brandtzaeg P, Briles DE, Brock JH, Bronson RA, Brown WR, Buckley MG, Butcher EC, Butler JE, Carlsen HS, Cassell GH, Cauci S, Cebra JJ, Challacombe SJ, Cheroutre H, Chikwamba R, Childers NK, Clancy RL, Compans RW, Cone RA, Corbeil LB, Crane-Godreau MA, Cripps AW, Cunningham-Rundles C, Curtiss R, Czerkinsky C, Czinn SJ, de Jong Y, Dent G, Dertzbaugh MT, DiRita VJ, Duchmann R, Elson CO, Emancipator SN, Estes MK, Fargarasan S, Faria AM, Farstad IN, Fidel PL, Fischer H, Fogg G, Fujihashi K, Fusi FM, Fuss IJ, Ganz T, Garofalo RP, Genco RJ, Gewirtz AT, Gleeson M, Godaly G, Goldblum RM, Grant KS, Greenberg HB, Haitchi HM, Hajishengallis G, Hamada H, Hanson LÅ, Hardy RD, Herias MV, Herrler G, Herrmann JE, Hodgins DC, Hoentjen F, Holgate ST, Holloway JH, Holmgren J, Hook EW, Hunt JS, Inman MD, Irjala H, Ishikawa H, Ishikawa T, Ivanyi J, Jackson S, Jalkanen S, Janoff EN, Jiang HQ, Kaetzel CS, Kanamori Y, Karp LC, Kato T, Kehrli ME, Kelsall BL, Kerr MA, Kilian M, Kiyono H, Knight KL, Korotkova M, Kraal G, Kraehenbuhl JP, Krieg AM, Krishna MT, Kroese FG, Kronenberg M, Kurono Y, Kutteh WH, Kweon MN, Lamm ME, Lazarus N, LeFrançois L, Lehner T, Lehrer RI, Leon F, Levine MM, Lim D, Lin TJ, Lomonossoff GP, Lundin KE, Lundstedt AC, Lycke N, MacDonald TT, Mahoney RT, Martin D, Mason HS, Masuyama K, Mayer L, McDonald DM, McElrath MJ, McGhee JR, Mestecky J, Michalek SM, Miller CJ, Miller RD, Mogi G, Molberg Ø, Moldoveanu Z, Monteleone G, Montgomery PC, Moro I, Morrison RP, Mostov K, Mowat AM, Murphy BR, Nataro JP, Nedrud JG, Neutra MR, Nowicki S, O'Byrne PM, Ofek I, Ogra PL, O'Hagan DT, Okamoto Y, Orihuela CJ, Osterhaus AD, O'Sullivan NL, Owen RL, Page RC, Parr MB, Parr EL, Parreño V, Pascual DW, Peppard JV, Petroff MG, Pudney J, Ravdin JI, Renegar KB, Rhee KJ, Rimmelzwaan GF, Robertson AK, Robinson HL, Rosenthal KL, Rothenberg ME, Rouse BT, Rubins JB, Russell MW, Saif LJ, Salmi M, Sampson HA, Samuelsson P, Santi L, Sartor RB, Savage DC, Schmid DS, Sharon N, Shirlaw PJ, Smith PD, Smythies LE, Sollid L, Sparling PF, Spearman PW, Spencer J, Strober W, Su W, Sullivan DA, Svanborg C, Svennerholm AM, Svensson ML, Targan SR, Taubman MA, Telemo E, Tenovuo J, Terhorst C, Tlaskalova-Hogenova H, Tristram DA, Tuomanen E, Underdown BJ, van Egmond M, Vijay-Kumar M, Wahl SW, Walker WA, Ward RL, Weaver CT, Weiner HL, Welliver RC, Wira CR, Woof JM, Wotherspoon AC, Youngman KR, Yuan L, Zeitz M. Contributors. Mucosal Immunol 2005. [DOI: 10.1016/b978-012491543-5/50003-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Sartor RB. Probiotic therapy of intestinal inflammation and infections. Curr Opin Gastroenterol 2005; 21:44-50. [PMID: 15687884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
PURPOSE OF REVIEW The author presents evidence published during the past year regarding treatment of clinical and experimental intestinal inflammation and infections by probiotic agents. RECENT FINDINGS Normal commensal bacteria are implicated in the pathogenesis of chronic, immune-mediated intestinal inflammation, particularly Crohn disease and pouchitis, whereas viral, bacterial, fungal, and protozoan infections are increasingly important with widespread use of immunosuppressive agents and broad-spectrum antibiotics. Combinations of Lactobacilli, Bifidobacteria, and Streptococcus salivarius prevent relapse of recurrent pouchitis and perhaps decrease the initial onset of pouch inflammation, whereas Escherichia coli Nissle 1917 maintains remission in ulcerative colitis. Several agents offer promise as primary therapy of ulcerative colitis. Use of probiotics in Crohn disease remains unsubstantiated. Animal models demonstrate marked differences in responses among various probiotic bacterial species and that nonviable organisms can have therapeutic efficacy. Probiotics have multiple mechanisms of action, including prevention of pathogenic bacterial growth, binding to or penetration of pathogens to mucosal surfaces, stimulation of mucosal barrier function, or altering immunoregulation (decreasing proinflammatory and promoting protective molecules). Although multiple probiotic species block epithelial adhesion and invasion by microbial pathogens in vitro, their proven utility in clinical infections is limited to accelerating recovery from acute infectious diarrhea and preventing antibiotic-associated diarrhea. SUMMARY Probiotics offer promise for physiologic, nontoxic treatment of pouchitis, ulcerative colitis, and acute infectious diarrhea, but larger, controlled clinical studies must be performed to clarify optimal agents; doses; combinations of various probiotics, prebiotics, and antibiotics; and therapeutic conditions.
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Affiliation(s)
- R Balfour Sartor
- Department of Medicine, UNC, Chapel Hill, North Carolina 27599-7032, USA.
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Schwerbrock NMJ, Makkink MK, van der Sluis M, Büller HA, Einerhand AWC, Sartor RB, Dekker J. Interleukin 10-deficient mice exhibit defective colonic Muc2 synthesis before and after induction of colitis by commensal bacteria. Inflamm Bowel Dis 2004; 10:811-23. [PMID: 15626900 DOI: 10.1097/00054725-200411000-00016] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Germ-free (GF) interleukin 10-deficient (IL-10) mice develop chronic colitis after colonization by normal enteric bacteria. Muc2 is the major structural component of the protective colonic mucus. Our aim was to determine whether primary or induced aberrations in Muc2 synthesis occur in GF IL-10 mice that develop colitis after bacterial colonization. GF IL-10 and wild-type mice were colonized with commensal bacteria for various intervals up to 6 weeks. Colitis was quantified by histologic score and IL-12 secretion. Muc2 synthesis, total level of Muc2, and Muc2 sulfation were measured quantitatively. GF IL-10 mice showed 10-fold lower Muc2 synthesis and Muc2 levels compared with GF wild-type mice, but Muc2 sulfation was not different. When bacteria were introduced, IL-10 mice developed colitis, whereas wild-type mice remained healthy. Muc2 synthesis was unchanged in wild-type mice, but IL-10 mice showed a peak increase in Muc2 synthesis 1 week after bacterial introduction, returning to baseline levels after 2 weeks. Total Muc2 levels decreased 2-fold in wild-type mice but remained at stable low levels in IL-10 mice. Upon introducing bacteria, Muc2 sulfation increased 2-fold in wild-type mice, whereas in IL-10 mice Muc2 sulfation decreased 10-fold. In conclusion, a primary defect in colonic Muc2 synthesis is present in IL-10 mice, whereas bacterial colonization and colitis in these mice led to reduced Muc2 sulfation. These quantitative and structural aberrations in Muc2 in IL-10 mice likely reduce the ability of their mucosa to cope with nonpathogenic commensal bacteria and may contribute to their susceptibility to develop colitis.
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Affiliation(s)
- Nicole M J Schwerbrock
- Pediatric Gastroenterology and Nutrition, Department of Pediatrics, Erasmus Medical Center, Rotterdam, The Netherlands
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