Isolated Lamina Propria Mononuclear Cells Research Articles

Interleukin-13 Mediates Non-Steroidal Anti-Inflammatory-Drug-Induced Small Intestinal Mucosal Injury with Ulceration.

Non-steroidal anti-inflammatory drugs (NSAIDs), which are antipyretics and analgesics, cause gastrointestinal disorders, such as inflammation and ulcers. To prescribe NSAIDs more safely, it is important to clarify the mechanism of NSAID-induced gastrointestinal mucosal injury. However, there is a paucity of studies on small intestinal mucosal damage by NSAIDs, and it is currently unknown whether inflammation and ulceration also occur in the small intestine, and whether mediators are involved in the mechanism of injury. Therefore, in this study, we created an animal model in which small intestinal mucosal injury was induced using NSAIDs (indomethacin; IDM). Focusing on the dynamics of immune regulatory factors related to the injury, we aimed to elucidate the pathophysiological mechanism involved. We analyzed the pathological changes in the small intestine, the expression of immunoregulatory factors (cytokines), and identified cytokine secretion and expression cells from isolated lamina propria mononuclear cells (LPMCs). Ulcers were formed in the small intestine by administering IDM. Although the mRNA expression levels of IL-1β, IL-6, and TNFα were decreased on day 7 after IDM administration, IL-13 mRNA levels increased from day 3 after IDM administration and remained high even on day 7. The IL-13 mRNA expression and the secretion of IL-13 were increased in small intestinal LPMCs isolated from the IDM-treated group. In addition, we confirmed that IL-13 was expressed in CD4-positive T cells. These results provided new evidence that IL-13 production from CD4-positive T cells in the lamina propria of the small intestine contributes to NSAID-induced mucosal injury.

The Affordable Care Act in North Carolina : A Look Back and Review of Coverage Changes.

Prior to the passage of the Affordable Care Act, many individuals across the state and country faced numerous barriers to accessing affordable and quality health care. This paper provides a review of health coverage in North Carolina before the ACA, the impact the ACA has had on access to health care, and how North Carolina could continue to benefit from "complete" implementation of the ACA.

Oral typhoid vaccine Ty21a elicits antigen-specific resident memory CD4+ T cells in the human terminal ileum lamina propria and epithelial compartments

BackgroundSalmonella enterica serovar Typhi (S. Typhi) is a highly invasive bacterium that infects the human intestinal mucosa and causes ~ 11.9–20.6 million infections and ~ 130,000–223,000 deaths annually worldwide. Oral typhoid vaccine Ty21a confers a moderate level of long-lived protection (5–7 years) in the field. New and improved vaccines against enteric pathogens are needed but their development is hindered by a lack of the immunological correlates of protection especially at the site of infection. Tissue resident memory T (TRM) cells provide immediate adaptive effector immune responsiveness at the infection site. However, the mechanism(s) by which S. Typhi induces TRM in the intestinal mucosa are unknown. Here, we focus on the induction of S. Typhi-specific CD4+TRM subsets by Ty21a in the human terminal ileum lamina propria and epithelial compartments.MethodsTerminal ileum biopsies were obtained from consenting volunteers undergoing routine colonoscopy who were either immunized orally with 4 doses of Ty21a or not. Isolated lamina propria mononuclear cells (LPMC) and intraepithelial lymphocytes (IEL) CD4+TRM immune responses were determined using either S. Typhi-infected or non-infected autologous EBV-B cell lines as stimulator cells. T-CMI was assessed by the production of 4 cytokines [interferon (IFN)γ, interleukin (IL)-2, IL-17A and tumor necrosis factor (TNF)α] in 36 volunteers (18 vaccinees and 18 controls volunteers).ResultsAlthough the frequencies of LPMC CD103+ CD4+TRM were significant decreased, both CD103+ and CD103− CD4+TRM subsets spontaneously produced significantly higher levels of cytokines (IFNγ and IL-17A) following Ty21a-immunization. Importantly, we observed significant increases in S. Typhi-specific LPMC CD103+ CD4+TRM (IFNγ and IL-17A) and CD103− CD4+TRM (IL-2 and IL-17A) responses following Ty21a-immunization. Further, differences in S. Typhi-specific responses between these two CD4+TRM subsets were observed following multifunctional analysis. In addition, we determined the effect of Ty21a-immunization on IEL and observed significant changes in the frequencies of IEL CD103+ (decrease) and CD103− CD4+TRM (increase) following immunization. Finally, we observed that IEL CD103− CD4+TRM, but not CD103+ CD4+TRM, produced increased cytokines (IFNγ, TNFα and IL-17A) to S. Typhi-specific stimulation following Ty21a-immunization.ConclusionsOral Ty21a-immunization elicits distinct compartment specific immune responses in CD4+TRM (CD103+ and CD103−) subsets. This study provides novel insights in the generation of local vaccine-specific responses.Trial registration This study was approved by the Institutional Review Board and registered on ClinicalTrials.gov (identifier NCT03970304, Registered 29 May 2019—Retrospectively registered, http://www.ClinicalTrials.gov/NCT03970304)

Low abundance of colonic butyrate-producing bacteria in HIV infection is associated with microbial translocation and immune activation.

Gut microbial translocation is a major driving force behind chronic immune activation during HIV-1 infection. HIV-1-related intestinal dysbiosis, including increases in mucosa-associated pathobionts, may influence microbial translocation and contribute to mucosal and systemic inflammation. Thus, it is critical to understand the mechanisms by which gut microbes and their metabolic products, such as butyrate, influence immune cell function during HIV-1 infection. A cross-sectional study was performed to compare the relative abundance of butyrate-producing bacterial (BPB) species in colonic biopsies and stool of untreated, chronic HIV-1-infected (n = 18) and HIV-1-uninfected (n = 14) study participants. The effect of exogenously added butyrate on gut T-cell activation and HIV-1 infection was evaluated using an ex-vivo human intestinal cell culture model. Species were identified in 16S ribosomal RNA sequence datasets. Ex-vivo isolated lamina propria mononuclear cells were infected with C-C chemokine receptor type 5-tropic HIV-1Bal, cultured with enteric gram-negative bacteria and a range of butyrate doses, and lamina propria T-cell activation and HIV-1 infection levels measured. Relative abundance of total BPB and specifically of Roseburia intestinalis, were lower in colonic mucosa of HIV-1-infected versus HIV-1-uninfected individuals. In HIV-1-infected study participants, R. intestinalis relative abundance inversely correlated with systemic indicators of microbial translocation, immune activation, and vascular inflammation. Exogenous butyrate suppressed enteric gram-negative bacteria-driven lamina propria T-cell activation and HIV-1 infection levels in vitro. Reductions in mucosal butyrate from diminished colonic BPB may exacerbate pathobiont-driven gut T-cell activation and HIV replication, thereby contributing to HIV-associated mucosal pathogenesis.

Novel anti-inflammatory agent 3-[(dodecylthiocarbonyl)-methyl]-glutarimide ameliorates murine models of inflammatory bowel disease.

To examine the effect of 3-[(dodecylthiocarbonyl)-methyl]-glutarimide (DTCM-G), a novel anti-inflammatory agent that inhibits lipopolysaccharide (LPS) activation of RAW264.7 macrophages, on murine models of colitis and RAW264.7 cells. Colitis was induced by rectally infusing trinitrobenzenesulfonic acid (TNBS) (1.5 mg in 50% ethanol) in BALB/c mice or orally administering 3% dextran sulfate sodium (DSS) for 5 days in C57BL/6 mice. The severity of colitis was assessed after intraperitoneally injecting DTCM-G (40 mg/kg). The anti-inflammatory properties of DTCM-G and its mechanisms were investigated in LPS-stimulated RAW264.7 cells. DTCM-G significantly ameliorated TNBS-induced colitis, according to the body weight loss, disease activity index, colonic obstruction, macroscopic colonic inflammation score, mucosal myeloperoxidase activity, and histopathology. Immunohistochemistry and isolated lamina propria mononuclear cells showed significantly reduced colonic F4/80(+) and CD11b(+) macrophage infiltration. DTCM-G significantly suppressed tumor necrosis factor (TNF)-α and interleukin (IL)-6 messenger RNA expression in the colon and attenuated DSS-induced colitis, according to the disease activity index and histopathology. In RAW264.7 cells, DTCM-G suppressed LPS-induced TNF-α/IL-6 production and enhanced glycogen synthase kinase-3β phosphorylation. DTCM-G attenuated murine experimental colitis by inhibiting macrophage infiltration and inflammatory cytokine expression. Thus, DTCM-G may be a promising treatment for inflammatory bowel disease.

A CD3-Specific Antibody Reduces Cytokine Production and Alters Phosphoprotein Profiles in Intestinal Tissues From Patients With Inflammatory Bowel Disease

T cells mediate the development of inflammation in inflammatory bowel disease (IBD). We investigated the effects of an antibody against CD3 called otelixizumab, which induces immune tolerance, in intestinal mucosa samples from patients. Intestinal tissues were isolated from patients undergoing routine endoscopy or from patients undergoing intestinal surgery for colon cancer or IBD; healthy surrounding tissues were collected as controls. Isolated lamina propria mononuclear cells (LPMCs) and mucosal tissue explants were incubated with otelixizumab for 24 or 48 hours. Production of inflammatory cytokines was determined by enzyme-linked immunosorbent assay. Levels of 36 cytokines and chemokines and phosphorylation of 39 receptor tyrosine kinases and signaling molecules were measured using protein arrays. Immunoblot analysis was used to analyze T-cell transcription factors. Incubation of intestinal tissues or LPMCs with otelixizumab reduced production of interferon gamma, interleukin (IL)-17A, and other inflammatory cytokines and chemokines, simultaneously increasing production of IL-10. Mucosal biopsy specimens from patients with IBD retained inflammation-associated tyrosine phosphoprotein profiles exvivo. Incubation of the inflamed tissue with otelixizumab reduced phosphorylation of these proteins to levels observed in control tissues. Otelixizumab also markedly reduced phosphorylation of proteins associated with T-cell receptor activation. Neutralization of IL-10 blocked the anti-inflammatory effects of otelixizumab. We observed anti-inflammatory effects of anti-CD3 in inflamed intestinal tissues from patients with IBD. The antibody appears to down-regulate T-cell activation via IL-10.

An in vitro model to evaluate the impact of the soluble factors from the colonic mucosa of collagenous colitis patients on T cells: enhanced production of IL-17A and IL-10 from peripheral CD4⁺ T cells.

Soluble factors from intestinal mucosal cells contribute to immune homeostasis in the gut. We have established an in vitro model to investigate the regulatory role of soluble factors from inflamed intestinal mucosa of collagenous colitis (CC) patients in the differentiation of T cells. Peripheral blood CD4+ T cells from healthy donors were polyclonally activated in the presence of conditioned medium (CM) generated from denuded biopsies (DNB) or isolated lamina propria mononuclear cells (LPMCs) from mucosal biopsies from CC patients compared to noninflamed controls, to determine proliferation and secretion of cytokines involved in T-cell differentiation. Compared to controls, we observed significantly increased production of the proinflammatory cytokines IFN-γ, IL-17A, IL-6, and IL-1β and the anti-inflammatory cytokines IL-4 and IL-10 in the presence of CC-DNB-CM. The most pronounced effect of CC-LPMC-CM on peripheral CD4+ T cells was a trend towards increased production of IL-17A and IL-10. A trend towards reduced inhibition of T-cell proliferation was noted in the presence of CC-DNB-CM. In conclusion, our in vitro model reveals implications of soluble factors from CC colonic mucosa on peripheral T cells, enhancing their production of both pro- and anti-inflammatory cytokines.

Evidence that autophagy, but not the unfolded protein response, regulates the expression of IL-23 in the gut of patients with ankylosing spondylitis and subclinical gut inflammation

ObjectivesInterleukin (IL)-23 has been implicated in the pathogenesis of ankylosing spondylitis (AS). The aim of the study was to clarify the mechanisms underlying the increased IL-23 expression in the gut...

OP0278 Autophagy, but Not the Unfolded Protein Response, Regulates the Expression of IL-23 in the Gut of Patients with Ankylosing Spondylitis and Subclinical Gut Inflammation

BackgroundIL-23 is a heterodimeric cytokine that has been implicated in the pathogenesis of Ankylosing Spondylitis (AS). High serum and tissue levels for this cytokine have been demonstrated in AS and...

Mucosal CXCR4+ IgG plasma cells contribute to the pathogenesis of human ulcerative colitis through FcγR-mediated CD14 macrophage activation

BackgroundChronic inflammation characterised by IgG-producing plasma cell infiltration of colonic mucosa is a histological hallmark of ulcerative colitis (UC); however, whether its function is pathogenic or protective remains unclear.ObjectiveTo explore...

Diarrhea during the Conditioning Regimen Is Correlated with the Occurrence of Severe Acute Graft-versus-Host Disease through Systemic Release of Inflammatory Cytokines

Graft-versus-host disease (GVHD) is a major obstacle to the success of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although many indicators have been used to predict GVHD, the prediction of GVHD remains very difficult. Determining how to predict the occurrence of acute GVHD (aGVHD) as exactly as possible has been a huge challenge so far. Systemic release of inflammatory cytokines during the conditioning regimen and early-phase post-HSCT plays a crucial role in the generation of aGVHD; additionally, the conditioning regimen causes the damage to the intestinal tract. Diarrhea is a common symptom of intestinal tract damage during the conditioning regimen. We therefore performed a prospective study to investigate the relationship between diarrhea related to the conditioning regimen, systemic release of inflammatory cytokines during the conditioning regimen and the early-phase post-HSCT, and the development of aGVHD. This study demonstrated that duration of diarrhea was >5.5 days, with a maximal volume >8.72 mL/kg and a mean volume of diarrhea for days -3 to 0 >7.94 mL/kg were risk factors of grade II to IV aGVHD. Diarrhea with any 1 risk factor was defined as severe diarrhea. Furthermore, this study first confirmed that the correlation between diarrhea and aGVHD was related to the serum levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 during the conditioning regimen and during the early phase after transplantation. Our study demonstrated that diarrhea related to the conditioning regimen could be used as a marker for the prediction of aGVHD and further explain the possible mechanism underlying the linkage described here. Therefore, for the patients with severe diarrhea related to the conditioning regimen, low-dose glucocorticoid may be used to reduce the levels of inflammatory cytokine release by a damaged intestinal tract, and possibly further reduce the occurrence of aGVHD. For these patients, prophylaxis of aGVHD may be need to be adjusted individually.

A novel population of human CD56+ human leucocyte antigen D-related (HLA-DR+) colonic lamina propria cells is associated with inflammation in ulcerative colitis

Ulcerative colitis (UC) involves inappropriate mucosal immune responses to intestinal microbiota. Gut dendritic cells (DC) are central immunoregulators of the response to commensal bacteria, and the subset of CD11c(+) cells within the human leucocyte antigen D-related (HLA-DR(+)) lineage (lin)(-/dim) population are activated in inflammatory bowel disease. We hypothesized that CD11c(-) cells within this population may also be involved in intestinal inflammation. HLA-DR(+) lin(-/dim) cells were identified in freshly isolated lamina propria mononuclear cells by multi-colour flow cytometry in 54 UC patients and 22 controls. Proportion and number of CD11c(+) and CD11c(-) cells, and surface expression of activation markers CD40, CD86, Toll-like receptor (TLR)-2, TLR-4, and CD56(+)[natural killer (NK) marker], were determined. Cytokine production was assessed by intracellular staining. Lamina propria colonic CD11c(-) HLA-DR(+) lin(-/dim) cells were increased significantly in inflamed and 'non-inflamed' UC tissue, compared with control tissue. CD11c(+) HLA-DR(+) lin(-/dim) cells were unchanged. Fewer CD11c(-) cells expressed activation markers and produced intracellular cytokines than their CD11c(+) counterparts, and they were weakly stimulatory in mixed leucocyte reactions. Few CD11c(-) cells expressed blood plasmacytoid DC markers, but a major subset expressed high levels of CD56. CD11c(-) cells decreased after inflammation resolved. Intestinal inflammation in UC is associated with the presence of cells that share phenotypic features of both DC and NK cells. This novel population of human colonic CD56(+) HLA-DR(+) cells may play a role in immune regulation or tissue repair. Their increase in quiescent UC may be a marker of subclinical inflammation.

Positive Role of CCAAT/Enhancer-Binding Protein Homologous Protein, a Transcription Factor Involved in the Endoplasmic Reticulum Stress Response in the Development of Colitis

Although recent reports suggest that the endoplasmic reticulum (ER) stress response is induced in association with the development of inflammatory bowel disease, its role in the pathogenesis of inflammatory bowel disease remains unclear. The CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP) is a transcription factor that is involved in the ER stress response, especially ER stress-induced apoptosis. In this study, we found that experimental colitis was ameliorated in CHOP-null mice, suggesting that CHOP exacerbates the development of colitis. The mRNA expression of Mac-1 (CD11b, a positive regulator of macrophage infiltration), Ero-1alpha, and Caspase-11 (a positive regulator of interleukin-1beta production) in the intestine was induced with the development of colitis, and this induction was suppressed in CHOP-null mice. ERO-1alpha is involved in the production of reactive oxygen species (ROS); an increase in ROS production, which is associated with the development of colitis in the intestine, was suppressed in CHOP-null mice. A greater number of apoptotic cells in the intestinal mucosa of wild-type mice were observed to accompany the development of colitis compared with CHOP-null mice, suggesting that up-regulation of CHOP expression exacerbates the development of colitis. Furthermore, this CHOP activity appears to involve various stimulatory mechanisms, such as macrophage infiltration via the induction of Mac-1, ROS production via the induction of ERO-1alpha, interleukin-1beta production via the induction of Caspase-11, and intestinal mucosal cell apoptosis.

CpG-oligodeoxynucleotides stimulate immunoglobulin A secretion in intestinal mucosal B cells

Bacterial DNA motifs (such as CpG-oligodeoxynucleotides: CpG-ODN) induce innate immune responses via binding to Toll-like-receptor-9 (TLR-9). In murine intestinal mucosa treatment with CpG-ODN worsens chronic intestinal inflammation, whereas it prevents or ameliorates colitis when given in a prophylactic setting. In tonsils B cells have been reported to express TLR-9, especially after activation. Whether B cells in the human intestinal mucosa also express TLR-9 and whether their function can be influenced by CpG-ODN is, so far, unknown. Mucosal B cells were isolated according to a new protocol from surgical specimens of patients with inflammatory bowel disease and from controls by collagenase digestion followed by magnetic cell sorting using anti-CD19 antibody armed magnetic beads. TLR-9 mRNA and protein expression were quantified by real-time polymerase chain reaction (PCR) and Western blot, respectively. Immunoglobulin A (IgA) secretion was measured by enzyme-linked immunosorbent assay after stimulation of isolated B cells with CpG-ODN, control GpC-ODN or lipopolysaccharide (LPS). Flow cytometric analysis of the isolated lamina propria mononuclear cells showed a purification of 73% (+/-22%) CD19(+) cells. By quantitative reverse transcription-PCR and by Western blot TLR-9 expression in this cell population was evident. IgA secretion was increased significantly by CpG-ODN incubation compared with GpC-ODN and LPS. Compared with unstimulated controls, CpG-ODN up-regulated IgA secretion to 139% (+/-21%). These data demonstrate that CD19(+) mucosal B cells express TLR-9 and secrete increased levels of IgA upon stimulation with CpG-ODN, indicating an additional link between adaptive and innate intestinal immune responses.

Enhanced secretion of tumour necrosis factor-alpha, IL-6, and IL-1 beta by isolated lamina propria mononuclear cells from patients with ulcerative colitis and Crohn's disease.

The perpetuation of inflammation in ulcerative colitis and Crohn's disease may be regulated in part by an increased secretion of proinflammatory cytokines due to either an appropriate response to initial stimulating agents, and/or due to an impaired down-regulation of cytokine secretion. The aim of this study was to determine the secretion patterns of the proinflammatory cytokines tumour necrosis factor-alpha (TNF-alpha), IL-6 and IL-1 beta, from isolated lamina propria mononuclear cells (LPMNC) isolated from colonic biopsies from patients with untreated ulcerative colitis or Crohn's disease. LPMNC isolated from involved inflammatory bowel disease (IBD) mucosa spontaneously produced increased amounts of TNF-alpha, and IL-6, and IL-1 beta. The TNF-alpha secretion from IBD LPMNC could be further enhanced by pokeweed mitogen stimulation. The secretion patterns of TNF-alpha and IL-1 beta by LPMNC from patients with either ulcerative colitis or Crohn's disease demonstrated a close correlation with the degree of tissue involvement and mucosal inflammation. LPMNC from non-involved ulcerative colitis mucosa secreted markedly increased levels of IL-6 compared with non-involved Crohn's disease mucosa or control mucosa. The heightened IL-6 secretion from LPMNC from non-involved ulcerative colitis mucosa without visible or microscopic signs of inflammation indicates that the pathophysiologic mechanisms involved in the initiation of inflammation may differ between ulcerative colitis and Crohn's disease. The determination of proinflammatory cytokine secretion by isolated LPMNC from colonoscopic biopsies may be a sensitive method for monitoring the severity of mucosal inflammation in IBD patients.

IL-2 production by intestinal lamina propria cells in normal inflamed and cancer-bearing colons.

Biologically significant levels of IL-2 activity were produced by isolated lamina propria mononuclear cells (LPMC) from normal intestine (n = 12), cancer-bearing colons (n = 35) and inflammatory bowel disease (IBD) affected tissue (n = 12). The levels of IL-2 produced were similar for all three sources of LPMC (normal 252 +/- 48 U/ml, IBD-affected mucosa 197 +/- 42 U/ml and colon cancer 285 +/- 43 U/ml). These levels were significantly greater than those produced by peripheral blood mononuclear cells (20 +/- 5 U/ml, P less than 0.01) on a per cell basis. In mucosa from cancer-bearing colons the amount of IL-2 produced by LPMC was unaffected by the invasiveness of the colon cancer. LPMC IL-2 production was markedly suppressed by drugs used in IBD therapy. 5-Aminosalicylic acid (5-ASA) reduced activity in a dose-dependent fashion. At a dose equivalent to the faecal therapeutic level of 0.5 mg/ml activity, IL-2 production by LPMC was suppressed to 3.4% of controls. Similarly, exposure of LPMC to cyclosporin A (CyA) and hydrocortisone (HC) at therapeutic levels reduced IL-2 activity to less than 1% of controls. The major producers of IL-2 activity were shown to be CD3+ T lymphocytes and those bearing the activation markers IL-2R and TFR. Suppression of mucosal IL-2 production represents an important therapeutic mechanism of drugs used in the management of IBD including HC, 5-ASA and CyA. These results suggest that mucosal T cells produce appreciable levels of IL-2 activity that may be important in maintaining immune homeostasis in the normal intestine, provide anti-neoplastic cytotoxic activity and contribute to the inflammatory events that characterize the mucosal lesions of IBD.

T1217 A Novel Population of CD56+ HLA-DR+ Colonic Lamina Propria Cells Is Associated with Inflammation in Ulcerative Colitis

INTRODUCTION: The immunopathology of ulcerative colitis (UC) relates to an inappropriate mucosal immune response to constituents of the intestinal microbiota in genetically susceptible individuals. HLA-DR+ lin-/dim (lin = anti-CD3,14,16,19,34) cells extracted from human intestinal tissue contain CD11c+ myeloid dendritic cells (DC) that contribute to the immunoregulatory events that normally limit inflammatory responses to commensal bacteria. Also present within the HLA-DR+ lin-/dim population are hitherto poorly characterized CD11ccells. We hypothesized that this population in the gut may also contribute to intestinal inflammation in active UC AIMS & METHODS: HLA-DR+ lin-/dim cells were identified in freshly isolated lamina propria mononuclear cells by multicolour flow cytometry, from patients with UC (n=48) and controls (n=22). The proportion and number of CD11c+ and CD11ccells within this population were determined. Surface expression of the activation/maturation markers CD40, CD86, Toll-like receptors (TLR), TLR-2, TLR-4, and the natural killer cell marker, CD56 was assessed on each cell population. Morphology was assessed by electron microscopy and T cell stimulatory capacity measured in allogenic mixed leucocyte reaction (MLR). RESULTS: Lamina propria colonic HLA-DR+ lin-/dim cells, of the CD11c-, but not the CD11c+ subset, were significantly increased in inflamed tissue of patients with UC compared with control tissue (UC 447±94 versus Control 104±17 per mg; p<0.001). Numbers of CD11cHLA-DR+ lin-/dim cells decreased after resolution of macroscopic inflammation. Nonetheless, CD11cHLA-DR+ lin-/dim cells were significantly increased in non-inflamed tissue of UC patients compared with colonic tissue from healthy subjects (p<0.05). In UC, these CD11ccells expressed CD40, CD86, TLR-2 and TLR-4 at lower levels than on their CD11c+ counterparts and were weakly stimulatory in an MLR. Few CD11cHLA-DR+ lin-/dim colonic cells expressed markers associated with blood CD11cHLA-DR+ lin-/dim plasmacytoid DC (BDCA2, BDCA4 and high levels of CD123) but a major subset expressed high levels of the Natural Killer (NK)marker CD56. CONCLUSION: Intestinal inflammation in UC is associated with the presence of a population of cells that share phenotypic features of both antigen presenting cells and NK cells. This novel population of human colonic cells may function in immune regulation or tissue repair. In addition, their increased presence in quiescent UCmay be amarker of sub-clinical inflammatory activity

An Herbal Medicine Orengedokuto Prevents Indomethacin-Induced Enteropathy

Prostaglandin E2 (PGE2) is a key regulator of gastrointestinal, immunological, and mucosal homeostasis. Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the prostaglandin-producing enzyme cyclooxygenases (COXs), and can induce serious complications, such as gastrointestinal damage, with long-term treatment. Orengedokuto (OGT), a Japanese traditional herbal medicine (Kampo medicine), is effective in various animal models of enteropathy. In the present study we examined whether OGT prevents enteropathy induced by NSAIDs in mice. Ulceration in the small intestine was induced with 2 subcutaneous injections of indomethacin (20 mg/kg body weight). Orally administered OGT prevented or reduced lethality, intestinal lesions, bleeding, increased serum nitrate/nitrite levels, and reduction of mucosal PGE2 induced by indomethacin. These beneficial effects of OGT were accompanied by increased production of PGE2 and interleukin 10 by isolated lamina propria mononuclear cells; COX-2 in these cells may be a major source of PGE2 in normal intestines. These findings suggest that OGT could be an effective therapeutic agent for the treatment of inflammatory bowel disease and adverse reactions to NSAIDs.

Role of TL1A and its receptor DR3 in two models of chronic murine ileitis.

TL1A is a TNF-like cytokine that binds to the death-domain receptor (DR)3 and provides costimulatory signals to activated lymphocytes. Through this interaction, TL1A induces secretion of IFN-gamma and may, therefore, participate in the development of T helper-1-type effector responses. In this study, we investigated whether interactions between TL1A and DR3 are involved in the pathogenesis of chronic murine ileitis. We demonstrate that alternative splicing of DR3 mRNA takes place during the activation of lymphocytes, which results in up-regulation of the complete/transmembrane (tm) form of DR3. Using two immunogenetically distinct animal models of Crohn's disease, we demonstrate that induction of intestinal inflammation is associated with significant up-regulation of TL1A and tm DR3 in the inflamed mucosa. In addition, within isolated lamina propria mononuclear cells from mice with inflammation, TL1A is primarily expressed on CD11c(high) dendritic cells. We also report that TL1A acts preferentially on memory CD4(+)/CD45RB(lo) murine lymphocytes by significantly inducing their proliferation, whereas it does not affect the proliferation of the naïve CD4(+)/CD45RB(hi) T helper cell subpopulation. Finally, we demonstrate that TL1A synergizes with both the cytokine-dependent IL-12/IL-18 pathway and with low-dose stimulation of the T cell receptor to significantly induce the secretion of IFN-gamma via an IL-18-independent pathway. Our results raise the possibility that interaction(s) between TL1A expressed on antigen-presenting cells and tm DR3 on lymphocytes may be of particular importance for the pathogenesis of chronic inflammatory conditions that depend on IFN-gamma secretion, including inflammatory bowel disease. Blockade of the TL1A/DR3 pathway may, therefore, offer therapeutic opportunities in Crohn's disease.

Characteristics of Intestinal Dendritic Cells in Inflammatory Bowel Diseases

Dendritic cells (DCs) recognize and respond to microbial structures using pattern recognition receptors, including Toll-like receptors (TLRs). In the intestine, DCs are pivotal in tolerance induction and direct the differentiation of T cells. We aimed to identify changes in intestinal DCs that may underlie the dysregulated immune response to enteric bacteria that occurs in patients with inflammatory bowel disease (IBD). DCs were identified in freshly isolated lamina propria mononuclear cells by multicolor flow cytometry in patients with IBD and controls. Expression of TLR2, TLR4, and the activation/maturation marker CD40 was assessed by cell surface labeling. Production of cytokines (interleukin [IL]-12, IL-6, and IL-10) was assessed in the absence of exogenous stimulation by intracellular staining of permeabilized cells. In healthy controls, few intestinal DCs expressed TLR2 or TLR4, in contrast to blood DCs. DC expression of both TLRs was significantly enhanced in Crohn's disease and ulcerative colitis. DCs from inflamed tissue of patients with Crohn's disease expressed significantly higher levels of the maturation/activation marker CD40. Elevated levels of CD40 on DCs were decreased after treating patients with anti-tumor necrosis factor alpha. In Crohn's disease, but not ulcerative colitis, more colonic DCs produced IL-12 and IL-6. The number of IL-10-producing DCs did not differ significantly between patients with IBD and controls. In IBD, DCs are activated, their expression of microbial recognition receptors is up-regulated, and more DCs produce pathologically relevant cytokines. Intestinal DCs are likely to be key initiators or perpetuators of the inflammatory response that characterizes IBD.