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Rodriguez-Sillke Y, Visekruna A, Glauben R, Siegmund B, Steinhoff U. Recognition of food antigens by the mucosal and systemic immune system: Consequences for intestinal development and homeostasis. Int J Med Microbiol 2021; 311:151493. [PMID: 33652373 DOI: 10.1016/j.ijmm.2021.151493] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 02/19/2021] [Accepted: 02/23/2021] [Indexed: 12/16/2022] Open
Abstract
The impact of nutrition on systemic and intestinal immune responses remains controversially discussed and yet not fully understood. The majority of studies investigating the effects of dietary antigens focused to understand how local and systemic unresponsiveness is induced by innocuous food antigens. Moreover, it has been shown that both, microbial and dietary antigens are essential for the normal development of the mucosal immune system. Based on experimental findings from animals and IBD patients, we propose a model how the intestinal immune system performs the balancing act between recognition and tolerance of dietary antigens at the same time: In the healthy gut, repetitive uptake of dietary antigens by Peyer's patches leads to increasing activation of CD4+ T cells till hyper-activated lymphocytes undergo apoptosis. In contrast to healthy controls, this mechanism was disturbed in Crohn's disease patients. This observation might help to better understand beneficial effects of dietary intervention therapy.
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Affiliation(s)
- Yasmina Rodriguez-Sillke
- Medical Department for Gastroenterology, Infectious Diseases and Rheumatology, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Germany
| | - Alexander Visekruna
- Institute for Medical Microbiology and Hygiene, Philipps University of Marburg, Marburg, Germany
| | - Rainer Glauben
- Medical Department for Gastroenterology, Infectious Diseases and Rheumatology, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Germany
| | - Britta Siegmund
- Medical Department for Gastroenterology, Infectious Diseases and Rheumatology, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Germany
| | - Ulrich Steinhoff
- Institute for Medical Microbiology and Hygiene, Philipps University of Marburg, Marburg, Germany.
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Crohn’s Disease. Mucosal Immunol 2015. [DOI: 10.1016/b978-0-12-415847-4.00082-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Keeping the bowel regular: the emerging role of Treg as a therapeutic target in inflammatory bowel disease. Inflamm Bowel Dis 2013; 19:2716-24. [PMID: 23899545 DOI: 10.1097/mib.0b013e31829ed7df] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The understanding of the intricate mechanisms by which gut immune cells interact with each other and the intestinal flora is constantly developing. The mucosal immune system must retain the ability to mount a prompt response to intestinal pathogens while maintaining tolerance for commensal organisms. Effector T lymphocytes drive inflammation, whereas their actions are counteracted by populations of regulatory T cells (Treg), which act as an endogenous suppressor of mucosal inflammation. There is growing evidence that a loss of this delicate counterbalance is important in the etiology of inflammatory bowel disease (IBD). Here, we review studies highlighting alterations in Treg in the pathogenesis of IBD. Observations of dynamic changes in Treg activity with successful IBD treatment have highlighted their functional importance and potential to also serve as a biomarker of disease activity and to predict response to therapy. Furthermore, we explore the potential for adoptive transfer of Treg as part of IBD treatment.
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Berndt U, Philipsen L, Bartsch S, Hu Y, Röcken C, Bertram W, Hämmerle M, Rösch T, Sturm A. Comparative Multi-Epitope-Ligand-Cartography reveals essential immunological alterations in Barrett's metaplasia and esophageal adenocarcinoma. Mol Cancer 2010; 9:177. [PMID: 20604962 PMCID: PMC2909181 DOI: 10.1186/1476-4598-9-177] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Accepted: 07/06/2010] [Indexed: 12/21/2022] Open
Abstract
Background Barrett's esophagus (BE) is caused by gastroesophageal reflux with consecutive mucosal inflammation, predisposing patients to the development of esophageal adenocarcinoma (EAC). We investigated changes in T cell-related mucosal combinatorial molecular protein patterns in both diseases using the novel Multi-Epitope-Ligand-Cartography, a unique robotic whole-cell imaging technology that simultaneously visualizes dozens of proteins in structurally intact tissues and correlates cellular localization of proteins with function. Results Biopsies were taken during endoscopy from BE, EAC, and normal control tissue, and proteomic microscopy was performed on 32 different epitopes. When the significance level was set to p < 0.0005 and the search depth to five antibody combinations, controls and BE can be differentiated by 63, controls and EAC by 3222, and BE from EAC by 1521 distinct protein combinations. For example, the number of activated apoptotic naïve and memory T cells was significantly increased only in BE, whereas the number of activated apoptotic helper and regulatory T cells was significantly elevated in BE and EAC. In contrast, the number of activated apoptotic cytotoxic T cells was significantly elevated only in EAC. Confirming different pathways in BE and EAC, the number of T lymphocytes with p53 expression and downregulation of bcl2 expression (CD3+p53+Bcl2-NfkB-) was significantly increased in EAC compared to BE and controls. Interestingly, the number of precursor T cells (CD7+) was significantly elevated only in EAC. These cells lack Bax and caspase-8, suggesting impaired apoptosis in the early stages of T cell differentiation. Conclusion Proteomic analysis showed for the first time that proteins, which are critically involved in the mucosal immune system of the esophagus, are distinctly expressed in BE and EAC, whereas others are comparably altered in both diseases, suggesting that many pathogenic events might be shared by both diseases. Topological proteomic analysis, therefore, helps us to understand the different pathogenic events in the underlying disease pathways.
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Affiliation(s)
- Uta Berndt
- Department of Medicine, Division of Gastroenterology and Hepatology, Charité-Campus Virchow Clinic, Universitätsmedizin Berlin, Germany.
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Yarkoni S, Sagiv Y, Kaminitz A, Farkas DL, Askenasy N. Targeted therapy to the IL-2R using diphtheria toxin and caspase-3 fusion proteins modulates Treg and ameliorates inflammatory colitis. Eur J Immunol 2009; 39:2850-64. [DOI: 10.1002/eji.200839190] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Hoffmann JC, Peters K, Pawlowski NN, Grollich K, Henschke S, Herrmann B, Zeitz M, Westermann J. In vivoProliferation of Rat Lamina Propria T Lymphocytes: General Hyporesponsiveness but Increased Importance of the CD2 and CD28 Pathways. Immunol Invest 2009; 38:466-82. [DOI: 10.1080/08820130902888342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Enteral and parenteral nutrition distinctively modulate intestinal permeability and T cell function in vitro. Eur J Nutr 2008; 48:12-21. [PMID: 18998044 DOI: 10.1007/s00394-008-0754-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Accepted: 10/21/2008] [Indexed: 01/08/2023]
Abstract
BACKGROUND Nutritional support is an established element of therapy for various indications. However, its impact on the mucosal barrier function is not well understood. AIM OF THE STUDY We investigated the influence of EN and PN on intestinal epithelial cells and peripheral blood (PBMC) and lamina propria mononuclear cells (LPMC), all of which are involved in the mucosal defense against bacterial translocation and systemic inflammation. METHODS Integrity of epithelial cells was measured as transepithelial electrical resistance (TER) of confluent Caco-2 monolayers in the presence of 1% EN, PN and a parenteral amino acid mixture (AM). To determine wound healing capacities, an established migration model with IEC-6 cells was used. Furthermore, we investigated apoptosis, cell activation, proliferation and cytokine secretion of Caco-2, HT29 and of stimulated PBMC and LPMC cultured with or without 1 and 5% EN, AM or PN. RESULTS We demonstrated that EN, AM and PN promoted the integrity of the epithelial monolayer and reconstituted epithelial cell continuity TGF-beta-dependently and -independently. Interestingly, only PN induced apoptosis and decreased the mitochondrial membrane potential. The activation status of PBMC was significantly reduced by EN and AM. Specifically, EN leads to an increased apoptosis rate, inhibited cell cycle progression and increased pro-inflammatory cytokine secretion. Both EN and PN reduced the activation status and the release of pro- and anti-inflammatory cytokines. CONCLUSIONS Our study provides evidence that by promoting wound healing and regulating T cell function, EN, AM, and PN potently interact with the intestinal barrier and immune system, thus justifying its use in diseases accompanied by impaired mucosal barrier function.
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Paclik D, Lohse K, Wiedenmann B, Dignass AU, Sturm A. Galectin-2 and -4, but not galectin-1, promote intestinal epithelial wound healing in vitro through a TGF-beta-independent mechanism. Inflamm Bowel Dis 2008; 14:1366-72. [PMID: 18484670 DOI: 10.1002/ibd.20499] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Inflammatory bowel diseases (IBDs) are characterized by various degrees of mucosal surface damage and subsequent impairment of the intestinal barrier function. Resealing of the epithelial barrier requires intestinal cell migration and proliferation. Galectins are increasingly recognized as novel regulators of inflammation. Thus, we aimed to explore the effect of galectin-2 (Gal-2) and Gal-4 on epithelial cell function and wound healing. METHODS Binding of Gal-2 and Gal-4 was determined by flow cytometric analysis and binding sites by SDS-PAGE electrophoresis. Cell migration by Gal-1, -2, and -4 was determined by a wound-healing assay. Cell cycle analysis and detection of apoptosis were determined by flow cytometric analysis. RESULTS Gal-2 and Gal-4 bind to epithelial cells at the E-cadherin/beta-catenin complex. Both galectins significantly enhanced intestinal epithelial cell restitution in vitro. This enhancement of epithelial cell restitution was TGF-beta-independent. In contrast, Gal-1 decreased epithelial cell migration TGF-beta dependently. By performing cell cycle analysis, we show that Gal-2 and Gal-4 increased cyclin B1 expression and consequently cell cycle progression, while Gal-1 inhibited cell cycling. Determining the influence of Gal-2 and Gal-4 on epithelial cell apoptosis, we showed no induction of apoptosis, whereas Gal-1 significantly induced apoptosis of epithelial cells caspase-independently. CONCLUSIONS Gal-2 and Gal-4 bind to intestinal epithelial cells and promote their restitution. Thus, our study provides for the first time evidence that these galectins play a significant role in intestinal wound-healing processes and might exert beneficial effects in diseases characterized by epithelial barrier disruption like IBDs.
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Affiliation(s)
- Daniela Paclik
- Medizinische Klinik m.S. Hepatologie and Gastroenterologie, Campus Virchow-Klinikum, Charité, Universitätsmedizin Berlin, Berlin, Germany
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Affiliation(s)
- Andreas Sturm
- Department of Hepatology and Gastroenterology, University Medicine Berlin, Berlin, Germany
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Yu QT, Saruta M, Papadakis KA. Visilizumab induces apoptosis of mucosal T lymphocytes in ulcerative colitis through activation of caspase 3 and 8 dependent pathways. Clin Immunol 2008; 127:322-9. [PMID: 18424236 DOI: 10.1016/j.clim.2008.02.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Revised: 02/13/2008] [Accepted: 02/18/2008] [Indexed: 11/30/2022]
Abstract
Visilizumab, a humanized low-Fc receptor binding anti-CD3 antibody, induces rapid clinical response in patients with steroid-refractory ulcerative colitis (UC). Several effective treatments in IBD have been linked to the induction of mucosal T cell apoptosis. The aim of the present study was to evaluate the effect of visilizumab on the apoptosis of lamina propria (LP) and peripheral blood (PB) lymphocytes isolated from patients with UC. Visilizumab induced dose- and time-dependent apoptosis of LP T cells isolated from non-IBD individuals, UC or CD patients. Maximal effect was seen at a concentration of 100 ng/ml and it was 33% for normal, 34% for UC and 23% for CD LP T cells following 24 h stimulation. Visilizumab induced apoptosis predominantly of CD4(+) LP T cells, whereas CD8(+) LP T cells were relatively resistant to apoptosis. Visilizumab did not induce apoptosis of PB T cells from UC patients. Visilizumab-induced apoptosis of LP T cells was dependent on caspase 3 and 8, but not caspase 9 activation and did not involve the Fas/FasL pathway. Low-Fc receptor binding Abs such as visilizumab may be highly effective for the treatment of UC through induction of apoptosis of LP T cells and rapid elimination of lesional pathogenic T cells in the gut mucosa.
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Affiliation(s)
- Qi T Yu
- Burns and Allen Research Institute, Division of Gastroenterology and Inflammatory Bowel Disease Center, Cedars-Sinai Medical Center, USA
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Berndt U, Bartsch S, Philipsen L, Danese S, Wiedenmann B, Dignass AU, Hämmerle M, Sturm A. Proteomic analysis of the inflamed intestinal mucosa reveals distinctive immune response profiles in Crohn's disease and ulcerative colitis. THE JOURNAL OF IMMUNOLOGY 2007; 179:295-304. [PMID: 17579049 DOI: 10.4049/jimmunol.179.1.295] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Although Crohn's disease (CrD) and ulcerative colitis (UC) share several clinical features, the mechanisms of tissue injury differ. Because the global cellular function depends upon the protein network environment as a whole, we explored changes in the distribution and association of mucosal proteins to define key events involved in disease pathogenesis. Endoscopic biopsies were taken from CrD, UC, and control colonic mucosa, and Multi-Epitope-Ligand-Cartographie immunofluorescence microscopy with 32 different Abs was performed. Multi-Epitope-Ligand-Cartographie is a novel, highly multiplexed robotic imaging technology which allows integrating cell biology and biomathematical tools to visualize dozens of proteins simultaneously in a structurally intact cell or tissue. In CrD, the number of CD3+CD45RA+ naive T cells was markedly increased, but only activated memory, but not naive, T cells expressed decreased levels of Bax, active caspase-3 or -8. In UC, only CD4+ T cells coexpressing NF-kappaB were caspase-8 and poly(ADP-ribose)-polymerase positive. Furthermore, the number of CD4+CD25+ T cells was elevated only in UC, whereas in CrD and controls, the number of these cells was similar. By using hub analysis, we also identified that the colocalization pattern with NF-kappaB+ and poly(ADP-ribose)-polymerase+ as base motifs distinguished CrD from UC. High-content proteomic analysis of the intestinal mucosa demonstrated for the first time that different T cell populations within the intestinal mucosa express proteins translating distinct biological functions in each form of inflammatory bowel disease. Thus, topological proteomic analysis may help to unravel the pathogenesis of inflammatory bowel disease by defining distinct immunopathogenic profiles in CrD and UC.
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Affiliation(s)
- Uta Berndt
- Division of Gastroenterology and Hepatology, Department of Medicine, Charité-Campus Virchow Clinic, Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany
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Vincent JA, Mohr S. Inhibition of caspase-1/interleukin-1beta signaling prevents degeneration of retinal capillaries in diabetes and galactosemia. Diabetes 2007; 56:224-30. [PMID: 17192486 DOI: 10.2337/db06-0427] [Citation(s) in RCA: 213] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The proinflammatory cytokine, interleukin (IL)-1beta, is known to induce vascular dysfunction and cell death. We investigated the role of IL-1beta and caspase-1 (the enzyme that produces it) in diabetes-induced degeneration of retinal capillaries. Caspase-1 activity is increased in retinas of diabetic and galactosemic mice and diabetic patients. First, we investigated the effect of agents known to inhibit caspase-1 (minocycline and tetracycline) on IL-1beta production and retinal capillary degeneration in diabetic and galactose-fed mice. Second, we examined the effect of genetic deletion of the IL-1beta receptor on diabetes-induced caspase activities and retinal capillary degeneration. Diabetic and galactose-fed mice were injected intraperitoneally with minocycline or tetracycline (5 mg/kg). At 2 months of diabetes, minocycline inhibited hyperglycemia-induced caspase-1 activity and IL-1beta production in the retina. Long-term administration of minocycline prevented retinal capillary degeneration in diabetic (6 months) and galactose-fed (13 months) mice. Tetracycline inhibited hyperglycemia-induced caspase-1 activity in vitro but not in vivo. Mice deficient in the IL-1beta receptor were protected from diabetes-induced caspase activation and retinal pathology at 7 months of diabetes. These results indicate that the caspase-1/IL-1beta signaling pathway plays an important role in diabetes-induced retinal pathology, and its inhibition might represent a new strategy to inhibit capillary degeneration in diabetic retinopathy.
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Affiliation(s)
- Jason A Vincent
- Case Western Reserve University, Department of Medicine, Division of Clinical and Molecular Endocrinology, Center for Diabetes Research, Cleveland, OH 44106, USA
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Henschke S, Pawlowski NN, Wild MK, Kroesen AJ, Zeitz M, Hoffmann JC. Lamina propria T cell activation: role of the costimulatory molecule CD2 and its cytoplasmic tail for the regulation of proliferation and apoptosis. Int J Colorectal Dis 2006; 21:321-31. [PMID: 16133008 DOI: 10.1007/s00384-005-0016-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/06/2005] [Indexed: 02/04/2023]
Abstract
BACKGROUND/AIMS Accumulation of T lymphocytes in the gut is a hallmark of inflammatory bowel disease probably caused by insufficient T cell apoptosis. Activated peripheral T cells, or "resting" lamina propria T lymphocytes (LPLs), are highly susceptible to apoptosis induction, e.g., using the mitogenic anti-CD2 monoclonal antibody (mAb) pair T11(2+3). It is, however, unknown how CD2-mediated LPL apoptosis is related to proliferation and whether the whole CD2 molecule is required for apoptosis induction. MATERIALS AND METHODS Mapping of anti-CD2 mAb was performed using erythrocyte rosetting assays and cross-blocking enzyme-linked immunosorbent assay (ELISA). Lamina propria mononuclear cells (LPMNCs) or phytohemagglutinin (PHA) blasts were stimulated with a panel of 18 anti-CD2 mAbs followed by apoptosis analysis [Annexin V expression on propidium iodide (PI)-negative cells, 4c6-diamidino-2-phenylindole x 2HCl (DAPI) staining]. Proliferation was measured by [(3)H]-thymidine incorporation. For structural analysis, EL4 cells were used which were transfected with human CD2 (wild type (WT), cytoplasmic-deficient, cytoplasmic CD28). Sorting was performed employing standard techniques RESULTS All three mitogenic anti-CD2 mAb pairs induced apoptosis of LPMNC and PHA blasts. Two out of four submitogenic anti-CD2 mAb, AICD2.M3, and ICRFCD2.3 lead to LPMNC proliferation but no apoptosis. Importantly, apoptosis was also detected in cytoplasmic-deficient CD2 tg or CD2/CD2/CD28 tg EL4 cells. Sorted CD45(high) huCD2 WT EL4 had higher apoptosis rates compared to WT huCD2tg EL4 cells CONCLUSION LPMNC apoptosis induction via CD2 is always associated with proliferation, although proliferation is not necessarily associated with apoptosis. The cytoplasmic tail of CD2 is not required, and CD45 appears to transmit apoptotic signals entering the T cell via CD2.
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Affiliation(s)
- Sven Henschke
- Innere Medizin II, Medizinische Klinik, Universitätskliniken des Saarlandes, 66421, Homburg/Saar, Germany
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Monteleone I, Monteleone G, Fina D, Caruso R, Petruzziello C, Calabrese E, Biancone L, Pallone F. A functional role of flip in conferring resistance of Crohn's disease lamina propria lymphocytes to FAS-mediated apoptosis. Gastroenterology 2006; 130:389-97. [PMID: 16472594 DOI: 10.1053/j.gastro.2005.10.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2004] [Accepted: 10/19/2005] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS There is evidence that, in Crohn's disease (CD), lamina propria T lymphocytes (LPLs) are resistant to FAS-mediated apoptosis and that this defect contributes to the mucosal T-cell accumulation. In this study we examined the functional role of Flip, a Flice inhibitor protein, in the resistance of CD LPL to FAS-mediated apoptosis. METHODS Biopsy specimens and LPLs were taken from CD and ulcerative colitis (UC) patients and normal controls and analyzed for Flip by Western blotting. We also examined whether inhibition of Flip by antisense oligonucleotide restored the susceptibility of CD LPLs to FAS-induced apoptosis. LPL apoptosis was assessed by flow cytometry. RESULTS After FAS stimulation, the rate of apoptosis of CD3+ LPLs was higher in normal controls and patients with UC than in patients with CD. Enhanced expression of both long and short Flip isoforms was seen in biopsy specimens and purified CD3+ and CD45RO+ LPLs of CD patients in comparison with UC patients and normal controls. No increase in Flip was documented in untreated celiac disease mucosa, thus suggesting the possibility that induction of Flip in the gut does not simply rely on the ongoing inflammation. Finally, we showed that inhibition of Flip by antisense oligonucleotide reverted the resistance of CD LPLs to FAS-induced apoptosis. CONCLUSIONS Data suggest a role for Flip in the resistance of CD LPLs to FAS-mediated apoptosis.
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Affiliation(s)
- Ivan Monteleone
- Dipartimento di Medicina Interna e Centro di Eccellenza per lo Studio Delle Malattie Complesse e Multifattoriali, Università Tor Vergata, Rome, Italy
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Reyes BMR, Danese S, Sans M, Fiocchi C, Levine AD. Redox equilibrium in mucosal T cells tunes the intestinal TCR signaling threshold. THE JOURNAL OF IMMUNOLOGY 2005; 175:2158-66. [PMID: 16081782 DOI: 10.4049/jimmunol.175.4.2158] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mucosal immune tolerance in the healthy intestine is typified by lamina propria T cell (LPT) functional hyporesponsiveness after TCR engagement when compared with peripheral blood T cell (PBT). When LPT from an inflamed intestine are activated through TCR cross-linking, their responsiveness is stronger. LPT are thus capable of switching from a tolerant to a reactive state, toggling between high and low thresholds of activation. We demonstrate that in normal LPT global tyrosine phosphorylation upon TCR cross-linking or an increase in intracellular H2O2, an inhibitor of protein tyrosine phosphatases, is muted. Thus, we propose that LPT have a greater reducing capacity than PBT, shifting the balance between kinases and protein tyrosine phosphatases in favor of the latter. Surface gamma-glutamyl transpeptidase, an indirect indicator of redox potential, and glutathione are significantly elevated in LPT compared with PBT, suggesting that elevated glutathione detoxifies TCR-induced reactive oxygen species. When glutathione is depleted, TCR-induced LPT tyrosine phosphorylation rises to PBT levels. Conversely, increasing glutathione in PBT attenuates tyrosine phosphorylation. In LPT isolated from inflamed mucosa, TCR cross-linking induces greater phosphorylation, and gamma-glutamyl transpeptidase levels are reduced compared with those from autologous noninflamed tissue. We conclude that the high TCR signaling threshold of mucosal T cells is tuned by intracellular redox equilibrium, whose dysregulation may mediate intestinal inflammation.
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Affiliation(s)
- Brenda M Rivera Reyes
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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Baumgart DC, Vierziger K, Sturm A, Wiedenmann B, Dignass AU. Mesalamine promotes intestinal epithelial wound healing in vitro through a TGF-beta-independent mechanism. Scand J Gastroenterol 2005; 40:958-64. [PMID: 16165710 DOI: 10.1080/00365520510015854] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Treatment with 5-aminosalicylic acid (5-ASA) derivatives is one of the main principles in the therapy of uncomplicated mild to moderate inflammatory bowel diseases (IBD). The beneficial effect of 5-ASA in the treatment of IBD is attributed to its anti-inflammatory and anti-oxidant properties within the inflamed gut. The aim of this study was to investigate whether 5-ASA also modulates intestinal epithelial wound repair in vitro. MATERIAL AND METHODS The effects of 5-ASA on cell migration and proliferation, two key processes in mucosal healing, were studied in the non-transformed small-intestinal epithelial cell line IEC-6 using an in vitro wounding model and colorimetric MTT assays. Furthermore, the effects of 5-ASA on epithelial cell viability were determined by Trypan blue exclusion and flow cytometry-based cell cycle analysis. RESULTS Clinically relevant concentrations of 5-ASA caused a significant dose-dependent enhancement of epithelial cell migration and proliferation in vitro. An about 2-fold enhancement of intestinal epithelial cell proliferation and migration was observed for pharmacological doses of 100 microg/ml 5-ASA. Neutralizing antibodies against TGFbeta did not modulate 5-ASA effects on IEC-6 cell proliferation and migration, indicating that the effects of 5-ASA were TGFbeta independent. Trypan blue viability tests and cell cycle analysis did not reveal any toxic or apoptotic effects of pharmacological 5-ASA concentrations on IEC-6 cells. CONCLUSIONS 5-ASA promotes the rapid re-establishment of mucosal integrity in vitro by enhancing epithelial restitution and proliferation, suggesting that 5-ASA in addition to the well-characterized effects on the intestinal inflammatory cascade may also directly stimulate epithelial wound healing.
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Affiliation(s)
- Daniel C Baumgart
- Department of Medicine, Division of Hepatology & Gastroenterology, Charité Medical Center-Virchow Hospital, Medical School of the Humboldt-University of Berlin, Germany
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Tursi A, Giorgetti GM, Brandimarte G, Elisei W. High prevalence of celiac disease among patients affected by Crohn's disease. Inflamm Bowel Dis 2005; 11:662-6. [PMID: 15973121 DOI: 10.1097/01.mib.0000164195.75207.1e] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Recent literature has shown a correlation between Crohn's disease (CD) and celiac disease, but a prospective study has not been performed. Our aim was to evaluate the prevalence of celiac disease in a consecutive series of patients affected by CD, in whom the disease was diagnosed for the first time. METHODS From January to December 2004, we diagnosed 27 patients affected by CD (13 men and 14 women; mean age, 32.3 yrs; range, 16-69 yrs). In all patients, we performed antigliadin, antiendomysium, and antitransglutaminase antibody tests, and the sorbitol H2 breath test evaluation. In case of antibodies and/or sorbitol positivity, esophagogastroduodenoscopy was performed for a small bowel biopsy. RESULTS Antigliadin, antiendomysium, and antitransglutaminase antibody tests were positive in 8/27 (29.63%), 4/27 (14.81%), and 5/27 (18.52%) patients, respectively, whereas the sorbitol H2 breath test was positive in 11/27 (40.74%) patients: all of them underwent esophagogastroduodenoscopy. Nine of 11 patients showed signs of duodenal endoscopic damage, and 5/9 (55.55%) showed histologic features of celiac disease (18.52% of overall CD population studied): 2 showed Marsh IIIc lesions (1 patient affected by ileal CD and 1 affected by ileo-colonic CD), 2 showed Marsh IIIb lesions (all of them affected by ileo-colonic CD), 1 showed a Marsh IIIa lesion (1 patient affected by colonic CD). CONCLUSIONS Prevalence of celiac disease seems to be high among patients affected by CD, and this finding should be kept in mind at the time of the first diagnosis of CD; a gluten-free diet should be promptly started.
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Affiliation(s)
- Antonio Tursi
- Digestive Endoscopy Unit, "Lorenzo Bonomo" Hospital, Andria, Italy.
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Escherichia coli Nissle 1917 distinctively modulates T-cell cycling and expansion via toll-like receptor 2 signaling. Infect Immun 2005. [PMID: 15731043 DOI: 10.1128/iai.73.3.1452-1465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Although the probiotic Escherichia coli strain Nissle 1917 has been proven to be efficacious for the treatment of inflammatory bowel diseases, the underlying mechanisms of action still remain elusive. The aim of the present study was to analyze the effects of E. coli Nissle 1917 on cell cycling and apoptosis of peripheral blood and lamina propria T cells (PBT and LPT, respectively). Anti-CD3-stimulated PBT and LPT were treated with E. coli Nissle 1917-conditioned medium (E. coli Nissle 1917-CM) or heat-inactivated E. coli Nissle 1917. Cyclin B1, DNA content, and caspase 3 expression were measured by flow cytometry to assess cell cycle kinetics and apoptosis. Protein levels of several cell cycle and apoptosis modulators were determined by immunoblotting, and cytokine profiles were determined by cytometric bead array. E. coli Nissle 1917-CM inhibits cell cycling and expansion of peripheral blood but not mucosal T cells. Bacterial lipoproteins mimicked the effect of E. coli Nissle 1917-CM; in contrast, heat-inactivated E. coli Nissle 1917, lipopolysaccharide, or CpG DNA did not alter PBT cell cycling. E. coli Nissle 1917-CM decreased cyclin D2, B1, and retinoblastoma protein expression, contributing to the reduction of T-cell proliferation. E. coli Nissle 1917 significantly inhibited the expression of interleukin-2 (IL-2), tumor necrosis factor alpha, and gamma interferon but increased IL-10 production in PBT. Using Toll-like receptor 2 (TLR-2) knockout mice, we further demonstrate that the inhibition of PBT proliferation by E. coli Nissle 1917-CM is TLR-2 dependent. The differential reaction of circulating and tissue-bound T cells towards E. coli Nissle 1917 may explain the beneficial effect of E. coli Nissle 1917 in intestinal inflammation. E. coli Nissle 1917 may downregulate the expansion of newly recruited T cells into the mucosa and limit intestinal inflammation, while already activated tissue-bound T cells may eliminate deleterious antigens in order to maintain immunological homeostasis.
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Sturm A, Rilling K, Baumgart DC, Gargas K, Abou-Ghazalé T, Raupach B, Eckert J, Schumann RR, Enders C, Sonnenborn U, Wiedenmann B, Dignass AU. Escherichia coli Nissle 1917 distinctively modulates T-cell cycling and expansion via toll-like receptor 2 signaling. Infect Immun 2005; 73:1452-65. [PMID: 15731043 PMCID: PMC1064918 DOI: 10.1128/iai.73.3.1452-1465.2005] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Although the probiotic Escherichia coli strain Nissle 1917 has been proven to be efficacious for the treatment of inflammatory bowel diseases, the underlying mechanisms of action still remain elusive. The aim of the present study was to analyze the effects of E. coli Nissle 1917 on cell cycling and apoptosis of peripheral blood and lamina propria T cells (PBT and LPT, respectively). Anti-CD3-stimulated PBT and LPT were treated with E. coli Nissle 1917-conditioned medium (E. coli Nissle 1917-CM) or heat-inactivated E. coli Nissle 1917. Cyclin B1, DNA content, and caspase 3 expression were measured by flow cytometry to assess cell cycle kinetics and apoptosis. Protein levels of several cell cycle and apoptosis modulators were determined by immunoblotting, and cytokine profiles were determined by cytometric bead array. E. coli Nissle 1917-CM inhibits cell cycling and expansion of peripheral blood but not mucosal T cells. Bacterial lipoproteins mimicked the effect of E. coli Nissle 1917-CM; in contrast, heat-inactivated E. coli Nissle 1917, lipopolysaccharide, or CpG DNA did not alter PBT cell cycling. E. coli Nissle 1917-CM decreased cyclin D2, B1, and retinoblastoma protein expression, contributing to the reduction of T-cell proliferation. E. coli Nissle 1917 significantly inhibited the expression of interleukin-2 (IL-2), tumor necrosis factor alpha, and gamma interferon but increased IL-10 production in PBT. Using Toll-like receptor 2 (TLR-2) knockout mice, we further demonstrate that the inhibition of PBT proliferation by E. coli Nissle 1917-CM is TLR-2 dependent. The differential reaction of circulating and tissue-bound T cells towards E. coli Nissle 1917 may explain the beneficial effect of E. coli Nissle 1917 in intestinal inflammation. E. coli Nissle 1917 may downregulate the expansion of newly recruited T cells into the mucosa and limit intestinal inflammation, while already activated tissue-bound T cells may eliminate deleterious antigens in order to maintain immunological homeostasis.
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Affiliation(s)
- Andreas Sturm
- Department of Hepatology and Gastroenterology, Campus Virchow Clinic, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany.
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Chen Y, Kelm RJ, Budd RC, Sobel BE, Schneider DJ. Inhibition of apoptosis and caspase-3 in vascular smooth muscle cells by plasminogen activator inhibitor type-1. J Cell Biochem 2004; 92:178-88. [PMID: 15095413 DOI: 10.1002/jcb.20058] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Increased expression of plasminogen activator inhibitor type 1 (PAI-1) is associated with decreased apoptosis of neoplastic cells. We sought to determine whether PAI-1 alters apoptosis in vascular smooth muscle cells (VSMC) and, if so, by what mechanisms. A twofold increase in the expression of PAI-1 was induced in VSMC from transgenic mice with the use of the SM-22alpha gene promoter (SM22-PAI+). Cultured VSMC from SM22-PAI+ mice were more resistant to apoptosis induced by tumor necrosis factor plus phorbol myristate acetate or palmitic acid compared with VSMC from negative control littermates. Both wild type (WT) and a stable active mutant form of PAI-1 (Active) inhibited caspase-3 amidolytic activity in cell lysates while a serpin-defective mutant (Mut) PAI-1 did not. Similarly, both WT and Active PAI-1 decreased amidolytic activity of purified caspase-3, whereas Mut PAI-1 did not. WT but not Mut PAI-1 decreased the cleavage of poly-[ADP-ribose]-polymerase (PARP), the physiological substrate of caspase-3. Noncovalent physical interaction between caspase-3 and PAI-1 was demonstrable with the use of both qualitative and quantitative in vitro binding assays. High affinity binding was eliminated by mutations that block PAI-1 serpin activity. Accordingly, attenuated apoptosis resulting from elevated expression of PAI-1 by VSMC may be attributable, at least in part, to reversible inhibition of caspase-3 by active PAI-1.
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Affiliation(s)
- Yabing Chen
- Department of Medicine, The University of Vermont, Burlington, Vermont 05405, USA.
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Dignass AU, Baumgart DC, Sturm A. Review article: the aetiopathogenesis of inflammatory bowel disease--immunology and repair mechanisms. Aliment Pharmacol Ther 2004; 20 Suppl 4:9-17. [PMID: 15352888 DOI: 10.1111/j.1365-2036.2004.02047.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Although the aetiopathogenesis of Crohn's disease and ulcerative colitis, remains unsolved, current evidence indicates that defective T-cell apoptosis and impairment of intestinal epithelial barrier function play important roles in the pathogenesis of both conditions. Without appropriate control of T-cell proliferation and death during an immune response, an inappropriate accumulation of T cells and subsequent intestinal inflammation may occur. Differences in T-cell responses between Crohn's disease and ulcerative colitis have been identified, with mucosal T-cell apoptosis being defective in Crohn's disease, but not in ulcerative colitis. Furthermore, cell cycling is considerably faster, with a vigorous clonal expansion, in Crohn's disease, whereas, in ulcerative colitis, T cells cycle normally, but have a remarkably reduced capacity to divide and expand. The elimination of excessive T cells therefore seems to be a reasonable approach to restore the gut to a physiological state or, at least, a controlled state of inflammation. The tumour necrosis factor-alpha blocker, infliximab, exerts its beneficial effects, at least in part, by the induction of apoptosis in lamina propria T cells and monocytes. In addition, repeated damage and injury of the intestinal surface is a hallmark of inflammatory bowel disease and may facilitate the entry of luminal antigens into the mammalian organism and the initiation and perpetuation of both nonspecific and specific immune responses. A better understanding of and enhancement of intestinal repair mechanisms may thus provide future approaches for the treatment of inflammatory bowel disease.
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Affiliation(s)
- A U Dignass
- Department of Medicine, Division of Hepatology and Gastroenterology, Charité Medical School--Virchow Hospital, Berlin, Germany.
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Sturm A, Krivacic KA, Fiocchi C, Levine AD. Dual Function of the Extracellular Matrix: Stimulatory for Cell Cycle Progression of Naive T Cells and Antiapoptotic for Tissue-Derived Memory T Cells. THE JOURNAL OF IMMUNOLOGY 2004; 173:3889-900. [PMID: 15356137 DOI: 10.4049/jimmunol.173.6.3889] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Tissue T cells encounter Ag in a distinct microenvironment, where they are embedded in the interstitial extracellular matrix (ECM). In contrast, while naive T cells are exposed to Ag in the lymph node, immediately after naive T cells are activated they must extravasate into the ECM to function effectively. Because integrin-mediated adhesion to the ECM modulates cell cycle progression and survival in adherent nonimmune cells, we hypothesize that blood and tissue-derived T cells have similarly adapted their behavior to their first or continued encounter with ECM. T cells from peripheral blood (PBT) and tissue (the intestinal lamina propria T cell (LPT)) were stimulated with anti-CD3-coated beads in the presence or absence of native ECM derived from intestinal fibroblasts, plate-immobilized fibronectin, or collagen type I. Native ECM and collagen, but not fibronectin, induced in anti-CD3 activated PBT a 4- to 5-fold increase in the entry, progression, and completion of the cell cycle over that triggered by anti-CD3 alone. Neutralizing beta1 integrin Abs abrogated this increase. None of these ECM proteins stimulated cell cycle progression in LPT. In contrast, anti-CD3 activation of LPT in the presence of native ECM and fibronectin reduced activation-induced cell death by 40%. These results demonstrate that naive and effector/memory T cells respond differently upon exposure to specific ECM components. When naive PBT encounter Ag in the context of ECM, their progression through the cell cycle is enhanced, favoring clonal expansion; while tissue T cell longevity may be mediated by interactions with the ECM.
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Affiliation(s)
- Andreas Sturm
- Department of Medicine, University Hospitals of Cleveland, Case Western Reserve University School of Medicine, OH 44106, USA
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Feinle-Bisset C, Vozzo R, Horowitz M, Talley NJ. Diet, food intake, and disturbed physiology in the pathogenesis of symptoms in functional dyspepsia. Am J Gastroenterol 2004; 99:170-81. [PMID: 14687160 DOI: 10.1111/j.1572-0241.2004.04003.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Functional dyspepsia (FD) remains a relatively poorly characterized gastrointestinal disorder of unknown etiology that is frequently difficult to manage. A systematic review of the literature relating to food intake and FD is summarized here. Many patients with FD report symptoms after meal ingestion, including fullness, bloating, epigastric pain, nausea, and vomiting, and this has been interpreted as indicative of an underlying "motor disorder of the stomach or small intestine." Such hypotheses are, however, still largely unsubstantiated, and the data that do exist are inconclusive, particularly as few studies have directly examined the temporal relationships between dyspeptic symptoms, meal ingestion, and disordered gastric motility. Moreover, studies attempting to relate symptoms to specific disturbances in gastric motor function have, in most cases, not evaluated symptoms concurrently with the function test, and/or have used suboptimal symptom scoring to quantify symptoms. Furthermore, the term "early satiety" has been used loosely as a symptom, rather than a quantitative measure of food intake. Currently, the most widely accepted mechanism underlying FD is visceral hypersensitivity, which may contribute to both enhanced motor and symptomatic responses to food ingestion. However, the possible contribution of food and dietary habits to the induction and/or exacerbation of dyspeptic symptoms represents a relatively new area-despite frequent reports by patients that their symptoms are often related to food ingestion; this association has not been formally assessed. Dietary assessments have frequently implicated fatty foods in symptom induction, and these findings are supported by laboratory-based studies, particularly the demonstration that FD patients more often experience symptoms after intraduodenal infusions of fat, than glucose. Further studies into the potential role of dietary factors in the induction of dyspeptic symptom are required to establish whether dietary therapies have any place in the management of FD.
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Affiliation(s)
- Christine Feinle-Bisset
- Department of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia
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Danese S, Katz JA, Saibeni S, Papa A, Gasbarrini A, Vecchi M, Fiocchi C. Activated platelets are the source of elevated levels of soluble CD40 ligand in the circulation of inflammatory bowel disease patients. Gut 2003. [PMID: 12970136 DOI: 10.1016/s0016-5085(03)80359-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND The CD40/CD40L system, a key regulator and amplifier of immune reactivity, is activated in inflammatory bowel disease (IBD) mucosa. AIMS To determine whether plasma levels of sCD40L are elevated in Crohn's disease (CD) and ulcerative colitis (UC) patients compared with normal controls, to investigate the cellular source of sCD40L, and to explore CD40L induction mechanisms. PATIENTS CD, UC, and normal control subjects were studied. METHODS The concentration of sCD40L in plasma and supernatants of freshly isolated platelets and autologous peripheral blood T cells (PBT) was measured by ELISA. Surface CD40L expression level was measured by flow cytometry in resting and thrombin activated platelets, and unstimulated and CD3/CD28 stimulated PBT before and after coculture with human intestinal microvascular endothelial cells (HIMEC). RESULTS Compared with normal controls, plasma sCD40L levels were significantly higher in both CD and UC patients and proportional to the extent of mucosal inflammation. Platelets from IBD patients displayed a significantly higher surface CD40L expression than those from control subjects, and released greater amounts of sCD40L than autologous PBT. Contact with IL-1beta activated HIMEC induced significant upregulation of CD40L surface expression and release by platelets. CONCLUSIONS Elevated levels of sCD40L in the circulation of IBD patients reflect enhanced surface expression and release of CD40L by platelets. This phenomenon translates to an increased platelet activation state apparently induced by passage through an inflamed mucosal microvascular bed, a conclusion supported by the positive correlation of plasma sCD40L levels with the extent of anatomical involvement by IBD. These results suggest that platelet-endothelial interactions critically contribute to activation of the CD40 pathway in IBD.
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Affiliation(s)
- S Danese
- Division of Gastroenterology, University Hospitals of Cleveland, Case Western Reserve University School of Medicine Cleveland, Ohio 44106-4952, USA
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Krivacic KA, Levine AD. Extracellular matrix conditions T cells for adhesion to tissue interstitium. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:5034-44. [PMID: 12734348 DOI: 10.4049/jimmunol.170.10.5034] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The activation and differentiation of peripheral blood T cells (PBT) are known to correlate with increased surface expression and adhesive capacity of beta(1) integrins, which mediate adhesion to the extracellular matrix (ECM). However, little is known about the regulation of integrin expression, affinity, and avidity on tissue T cells after they are embedded in the interstitial ECM. In this study we show that tissue T cells, freshly isolated from their residence in the interstitial ECM of the intestinal lamina propria, express a distinct subset of functionally active integrins that contribute to enhanced adhesion to purified collagen, fibronectin, and cell-derived ECM when compared with freshly isolated, short term activated, and long term cultured PBT. Furthermore, integrin usage is distinct between circulating and tissue-derived T cells, in that lamina propria T cells prefer to bind to collagen, while PBT lymphoblasts choose fibronectin when presented with a complex, three-dimensional, cell-derived matrix. To identify the extrinsic factors that regulate the conversion from a nonadhesive PBT to highly adhesive tissue T cell, we demonstrate that activation of PBT in the presence of fibronectin or collagen rapidly generates a surface integrin expression profile, an integrin usage pattern, and adhesive capacity mirroring that of a tissue T cell. These results indicate that the tissue ECM microenvironment instructs newly arrived T cells for further interactions with the underlying matrix and thereby imprints them with a signature tissue adhesive phenotype.
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Affiliation(s)
- Kimberly A Krivacic
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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Abstract
This article outlines the lymphoid structures and cell types important in the intestinal immune response. Particular attention is paid to differences between rodents and man where there appears to be fundamental differences in the sources of the T and B cells which populate the mucosa. The majority of the data still suggest that Peyer's patches are the inductive site of mucosal immunity and the mucosa (lamina propria and epithelium) is the effector site, but there is growing realization that mucosal immune responses can occur in the absence of Peyer's patches and that antigen sampling may also occur in the lamina propria.
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Affiliation(s)
- Thomas T MacDonald
- Division of Infection, Inflammation and Repair, University of Southampton School of Medicine, Southampton, UK.
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