Expression of CD45RB functionally distinguishes intestinal T lymphocytes in inflammatory bowel disease

The chromatin and single-cell transcriptional landscapes of CD4 T cells in inflammatory bowel disease link risk loci with a proinflammatory Th17 cell population

Introduction

The imbalance between Th17 and regulatory T cells in inflammatory bowel diseases (IBD) promotes intestinal epithelial cell damage. In this scenario, T helper cell lineage commitment is accompanied by dynamic changes to the chromatin that facilitate or repress gene expression.

Methods

Here, we characterized the chromatin landscape and heterogeneity of intestinal and peripheral CD4 T cellsfrom IBD patients using in house ATAC-Seq and single cell RNA-Seq libraries.

Results

We show that chromatin accessibility profiles of CD4 T cells from inflamed intestinal biopsies relate to genes associated with a network of inflammatory processes. After integrating the chromatin profiles of tissue-derived CD4 T cells and in-vitro polarized CD4 T cell subpopulations, we found that the chromatin accessibility changes of CD4 T cells were associated with a higher predominance of pathogenic Th17 cells (pTh17 cells) in inflamed biopsies. In addition, IBD risk loci in CD4 T cells were colocalized with accessible chromatin changes near pTh17-related genes, as shown in intronic STAT3 and IL23R regions enriched in areas of active intestinal inflammation. Moreover, single cell RNA-Seq analysis revealed a population of pTh17 cells that co-expresses Th1 and cytotoxic transcriptional programs associated with IBD severity.

Discussion

Altogether, we show that cytotoxic pTh17 cells were specifically associated with IBD genetic variants and linked to intestinal inflammation of IBD patients.

An Update of Research Animal Models of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a group of chronic disorders that includes two main disease forms, Crohn's disease, and ulcerative colitis. The understanding of the intestinal inflammation occurring in IBD has been immeasurably advanced by the development of the now numerous murine models of intestinal inflammation. The usefulness of this research tool in IBD arises from a convergence of underlying genetic susceptibility, immune system dysfunction, environmental factors, and shifts in gut microbiota. Due to the multifactorial feature of these diseases, different animal models have been used to investigate the underlying mechanisms and develop potential therapeutic strategies. The results of preclinical efficacy studies often inform the progression of therapeutic strategies. This review describes the distinct feature and limitations of each murine IBD model and discusses the previous and current lessons from the IBD models.

Localized hydrogel delivery of dendritic cells for attenuation of multiple sclerosis in a murine model

In multiple sclerosis (MS), abnormally activated immune cells responsive to myelin proteins result in widespread damage throughout the central nervous system (CNS) and ultimately irreversible disability. Immunomodulation by delivering dendritic cells (DCs) utilizes a potent and rapid MS disease progression driver therapeutically. Here, we investigated delivering DCs for disease severity attenuation using an experimental autoimmune encephalomyelitis preclinical MS model. DCs treated with interleukin-10 (IL-10) (DC10s) were transplanted using in situ gelling poly(ethylene glycol)-based hydrogel for target site localization. DC delivery increased hydrogel longevity and altered the injection site recruited, endogenous immune cell profile within 2 days postinjection. Furthermore, hydrogel-mediated DC transplantation efficacy depended on the injection-site. DCs delivered to the neck local to MS-associated CNS-draining cervical lymph nodes attenuated paralysis, compared to untreated controls, while delivery to the flank did not alter paralysis severity. This study demonstrates that local delivery of DC10s modulates immune cell recruitment and attenuates disease progression in a preclinical model of MS.

Association of Helicobacter bilis Infection with the Development of Colorectal Cancer

The role of Helicobacter_bilis (H.bilis) in the development of inflammatory bowel disease (IBD) and colitis-associated carcinogenesis (CAC) has seldom been investigated. We examined the abundance of H.bilis in 58 colorectal cancers (CRCs), 20 IBDs, 40 cases of normal colorectal mucosa (NCs), and 20 adenomas (ADs) by 16S rRNA fluorescence in situ hybridization (FISH). Number of CD4⁺CD45RB⁺T cell and expression of IFN-γ and TNF-α in these tissues was determined by immunofluorescence. The abundance of H.bilis was significantly higher in CRCs than that in IBDs (P = 0.006), ADs (P < 0.001) and NCs (P < 0.0001). The abundance of H.bilis in IBDs was significantly higher than that in ADs (P = 0.013). Moreover, the average number of CD4⁺CD45RB⁺T cell was significantly higher in CRCs than that in IBDs (P = 0.017) and NCs (P = 0.009). In addition, there was a positive correlation between the H.bilis abundance and density of CD4⁺CD45RB⁺T cells in 30 colorectal tissues (P < 0.0001). The frequency of co-staining for CD4⁺CD45RB⁺T cells and IFN-γ was significantly higher in H.bilis positive group than that in H.bilis negative group (P = 0.002). H.bilis may play a role in the initiation of IBD and CAC, possibly through promoting the transformation of T cells into CD4⁺CD45RB⁺T cells and increasing the expression of proinflammatory cytokines IFN-γ.

The Extracts of Morinda officinalis and Its Hairy Roots Attenuate Dextran Sodium Sulfate-Induced Chronic Ulcerative Colitis in Mice by Regulating Inflammation and Lymphocyte Apoptosis

Morinda officinalis is beneficial for the treatment of inflammatory bowel disease (IBD). The hairy root with higher genetic and biochemical stability cultured from M. officinalis might have similar effects to treat IBD. In this study, the main chemical composition of the root extracts of M. officinalis (MORE) native plant and the hairy root extract of M. officinalis (MOHRE) was compared by quantitative HPLC. The difference of their therapeutic effects and potential mechanism was evaluated using 3% dextran sodium sulfate-induced chronic colitis in mice and T lymphocytes in vitro. The results found that MOHRE possesses many specific peaks unobserved in the chromatogram of native plant. The content of iridoids in the MORE (3.10%) and MOHRE (3.01%) is somewhat similar but quite different for their anthraquinones’s content (0.14 and 0.66%, respectively). Despite all this, treatment with both MORE and MOHRE significantly attenuated the symptoms of colitis, including diarrhea, body weight loss, colon shortening, histological damage, and decreased inflammatory cytokine levels. In addition, they dose-dependently increased the apoptosis of T lymphocyte in vivo and in vitro. And, the differences for treatment effects on ulcerative colitis (UC) between them both in this study were mostly insignificant. The results demonstrated that the effects of MORE and MOHRE for the treatment of UC are similar, although there are a few difference on their chemical composition, indicating the hairy root cultured from M. officinalis might be able to replace its native plant on treatment of UC. The successful derivation of a sustainable hairy root culture provides a model system to study the synthetic pathways for bioactive metabolites, which will make the use of bioreactors to largely produce traditional medicine become reality.

Characteristics of Schistosoma japonicum infection induced IFN-γ and IL-4 co-expressing plasticity Th cells

Schistosoma japonicum infection can induce granulomatous inflammation and cause tissue damage in the mouse liver. The cytokine secretion profile of T helper (Th) cells depends on both the nature of the activating stimulus and the local microenvironment (e.g. cytokines and other soluble factors). In the present study, we found an accumulation of large numbers of IFN-γ(+)  IL-4(+)  CD4(+) T cells in mouse livers. This IFN-γ(+)  IL-4(+) cell population increased from 0·68 ± 0·57% in uninfected mice to 7·05 ± 3·0% by week 4 following infection and to 9·6 ± 5·28% by week 6, before decreasing to 6·3 ± 5·9% by week 8 in CD4 T cells. Moreover, IFN-γ(+)  IL-4(+) Th cells were also found in mouse spleen and mesenteric lymph nodes 6 weeks after infection. The majority of the IFN-γ(+)  IL-4(+) Th cells were thought to be related to a state of immune activation, and some were memory T cells. Moreover, we found that these S. japonicum infection-induced IFN-γ(+)  IL-4(+) cells could express interleukin-2 (IL-2), IL-9, IL-17 and high IL-10 levels at 6 weeks after S. japonicum infection. Taken together, our data suggest the existence of a population of IFN-γ(+)  IL-4(+) plasticity effector/memory Th cells following S. japonicum infection in C57BL/6 mice.

P2X7 receptor promotes intestinal inflammation in chemically induced colitis and triggers death of mucosal regulatory T cells

P2X7 receptor activation contributes to inflammation development in different pathologies. We previously reported that the P2X7 receptor is over-expressed in the gut mucosa of patients with inflammatory bowel disease, and that P2X7 inhibition protects against chemically induced colitis. Here, we investigated in detail the role of the P2X7 receptor in inflammatory bowel disease development, by treating P2X7 knockout (KO) and WT mice with two different (and established) colitis inductors. P2X7 KO mice were protected against gut inflammation induced by 2,4,6-trinitrobenzenesulfonic acid or oxazolone, with no weight loss or gut histological alterations after treatment. P2X7 receptor knockout induced regulatory T cell accumulation in the colon, as evaluated by qRT-PCR for FoxP3 expression and immunostaining for CD90/CD45RB^low. Flow cytometry analysis of mesenteric lymph node cells showed that P2X7 activation (by ATP) triggered regulatory T cell death. In addition, such cells from P2X7 KO mice expressed more CD103, suggesting increased migration of regulatory T cells to the colon (relative to the WT). Our results show that the P2X7 has a key role during inflammation development in inflammatory bowel disease, by triggering the death and retention in the mesenteric lymph nodes of regulatory T cells that would otherwise promote immune system tolerance in the gut.

The predominance of a naive T helper cell subset in the immune response of experimental acute pancreatitis

INTRODUCTION

In necrotizing acute pancreatitis (NAP), systemic inflammatory response syndrome (SIRS) and the compensatory anti-inflammatory response syndrome (CARS) decide overall outcome and mortality. In patients, low lymphocyte counts were found, but T-helper cells seemed to conversely increase. Our aim was to further categorize T-helper cells within the context of NAP induced SIRS and CARS.

METHODS

NAP was induced by injection of sodium-taurocholate into the common bile duct of male BALB/c mice; sham treated animals received saline infusion. The animals were sacrificed at 6, 12, 24 and 48 h later. Lymphocytes from blood, liver and spleen were isolated and examined by flow cytometry. Staining was performed for CD4, CD8, CD19, CD45RB, CD25, CD69, and CD152. CD4⁺ cells were sorted for their CD45RB expression and sought for gene regulation associated to T_H1/T_H2 cells by quantitative RT-PCR.

RESULTS

In NAP, CD4⁺ was solely increased in all compartments. CD8⁺ remained without substantial alterations. CD45RB showed significant expression in RB^high in T-helper cells, confirmed by the CD45RB^high/low ratio (Liver, 24 h: NAP 2.2, SHAM 0.6; p < 0.001). CD45RB^high and ^-low cells were not associated to patterns of T_H1/T_H2 expression. In NAP, CCR4 expression was significantly decreased within RB^high cells (fold change: 0.04, p < 0.05), while TLR6 showed significant overexpression (fold change: 2.36, p < 0.05).

CONCLUSION

T-helper cells increase in NAP, leaning towards CD45RB^high expression. They resemble naive T-cells, in which NAP leads to expression profiles associated with an innate immune response. This suggests new findings in immunological pathomechanisms of NAP.

Modulating the function of the immune system by thyroid hormones and thyrotropin

Accumulating evidence suggests a close bidirectional communication and regulation between the neuroendocrine and immune systems. Thyroid hormones (THs) can exert responses in various immune cells, e.g., monocytes, macrophages, natural killer cells, and lymphocytes, affecting several inflammation-related processes (such as, chemotaxis, phagocytosis, reactive oxygen species generation, and cytokines production). The interactions between the endocrine and immune systems have been shown to contribute to pathophysiological conditions, including sepsis, inflammation, autoimmune diseases and viral infections. Under these conditions, TH therapy could contribute to restoring normal physiological functions. Here we discuss the effects of THs and thyroid stimulating hormone (TSH) on the immune system and the contribution to inflammation and pathogen clearance, as well as the consequences of thyroid pathologies over the function of the immune system.

Chronic villitis of unknown etiology and massive chronic intervillositis have similar immune cell composition

INTRODUCTION

Chronic villitis of unknown etiology (CVUE) and massive chronic intervillositis (MCI) are placental lesions associated with infiltration of mononuclear cells in the chorionic villi and the intervillous spaces, respectively. It is not well known whether immune cells in CVUE and MCI have similar phenotypic characteristics.

METHODS

A cross-sectional study of third trimester placentas was conducted to identify immune cell subpopulations in CVUE and MCI (n = 17/group). CVUE was diagnosed with H&E staining and antibody to CD3 in serial sections; and MCI, by the presence of massive infiltration of mononuclear cells in the intervillous spaces. Immune cells, ICAM-1 expression and nuclear factor κB (NF-κB) activation were determined immunohistochemically.

RESULTS

CVUE and MCI showed similar infiltrates, mainly CD68+ and CD3+ cells. Most cells (>80%) were CD45RB+, and one third were CD45RO+ in both lesions. There were slightly more CD8+ than CD4+ cells in both CVUE and MCI. More than 90% of cells in CVUE and MCI were ICAM-1+ with NFκB nuclear localization. Syncytiotrophoblast ICAM-1 expression was significantly (p < 0.001) higher in MCI (mean of 81.0; range of 71.6-86.0) than in CVUE (52.4; 36.4-59.4) or normal placentas (0.2; 0.0-0.6). Both, failure of physiologic transformation of spiral arteries and placental atherosclerosis-like lesions of atherosis were significantly more frequent in MCI than in CVUE or normal placentas (p = 0.044 and p = 0.007, respectively).

DISCUSSION

These finding suggest that MCI and CVUE have very similar infiltration of immune cells although MCI has more severe placental lesions.

Oridonin's therapeutic effect: suppressing Th1/Th17 simultaneously in a mouse model of Crohn's disease

BACKGROUND AND AIM

Crohn's disease is a chronic inflammatory bowel disease. Oridonin is an effective component isolated from Rabdosia rubescens. It can inhibit the activation of transcription factor nuclear factor-kappa B and suppress the over expression of cytokines. We postulated that oridonin may be a potential therapeutic candidate for Crohn's disease.

METHODS

To confirm the postulation, we investigated clinical and immunologic modulations of oridonin in a mouse model of trinitrobenzene sulfonic acid-induced colitis.

RESULTS

It was found that oridonin attenuated trinitrobenzene sulfonic acid-induced colitis as represented by a reduction in colonic interferon-γ/inteleukin-17 secretion and a decrement in splenic Th1/Th17 cells and effector memory CD4(+) T cells. Oridonin treatment inhibited the proliferation of CD4(+) T cells and upregulated the apoptosis of lymphocytes by inhibiting nuclear translocation of transcription factor nuclear factor-kappa B.

CONCLUSIONS

Oridonin is a potential modulator for trinitrobenzene sulfonic acid-induced colitis and other Th1/Th17 mediated inflammatory diseases.

On naivety of T cells in inflammatory bowel disease: a review

: Little is known about different phases of T-cell maturation in gut mucosa. Based on current knowledge about the migratory pathways of naive and memory T cells, it is believed that access to peripheral, nonlymphoid tissues is restricted to memory T cells. Surprisingly, there is increasing evidence of high numbers of naive T cells in the chronically inflamed gut tissue of patients with inflammatory bowel disease. This could partially be explained by new formation of ectopic lymphoid organs. Ongoing recruitment of naive T cells at inflammatory sites might play a role in the immunopathogenesis of inflammatory bowel disease.

Naive T cells in the gut of newly diagnosed, untreated adult patients with inflammatory bowel disease

BACKGROUND

The phenotype of the T-cell subpopulations and their related cytokine networks in the gastrointestinal mucosa of patients with inflammatory bowel disease can potentially be used as a predictive value for clinical course and response to therapy. Here, we analyzed T-cell subpopulations in newly diagnosed, untreated adult patients and correlated them with clinical presentation.

METHODS

Mucosal biopsies from duodenum, ileum, and colon mucosa of patients with Crohn's disease and ulcerative colitis and controls were obtained. The simple endoscopy score in Crohn's disease and the full Mayo score in ulcerative colitis were used to score disease activity. Mucosa-infiltrating T cells were characterized by flow cytometric immunophenotyping and were stimulated to assess cytokine secretion.

RESULTS

Based on the expression of the maturation and activation markers CD45RA and CD27, we identified 4 different profiles. Profile A contained mainly CD45RA+CD27+ naive T cells; profile B contained mainly CD45RA+CD27+ central memory T cells; profile C contained mainly CD45RA-CD27- effector memory T cells; and profile D consisted of similar percentages of these aforementioned subpopulations. Profile A was only observed in the ileum/colon of patients with inflammatory bowel disease, associated with upper gastrointestinal location and perianal disease in Crohn's disease and expressed more tumor necrosis factor α and less interferon γ. In contrast, profile D was restricted to controls. There was no correlation between the different T-cell profiles and endoscopic disease activity.

CONCLUSIONS

Newly diagnosed patients with inflammatory bowel disease display different T-cell maturation profiles in the gut mucosa, corresponding to distinct cytokine responses. Follow-up studies are needed to determine whether the profiles associate with clinical course and response to therapy.

Mucopolysaccharide diseases: a complex interplay between neuroinflammation, microglial activation and adaptive immunity

Mucopolysaccharide (MPS) diseases are lysosomal storage disorders (LSDs) caused by deficiencies in enzymes required for glycosaminoglycan (GAG) catabolism. Mucopolysaccharidosis I (MPS I), MPS IIIA, MPS IIIB and MPS VII are deficient in the enzymes α-L-Iduronidase, Heparan-N-Sulphatase, N-Acetylglucosaminidase and Beta-Glucuronidase, respectively. Enzyme deficiency leads to the progressive multi-systemic build-up of heparan sulphate (HS) and dermatan sulphate (DS) within cellular lysosomes, followed by cell, tissue and organ damage and in particular neurodegeneration. Clinical manifestations of MPS are well established; however as lysosomes represent vital components of immune cells, it follows that lysosomal accumulation of GAGs could affect diverse immune functions and therefore influence disease pathogenesis. Theoretically, MPS neurodegeneration and GAGs could be substantiating a threat of danger and damage to alert the immune system for cellular clearance, which due to the progressive nature of MPS storage would propagate disease pathogenesis. Innate immunity appears to have a key role in MPS; however the extent of adaptive immune involvement remains to be elucidated. The current literature suggests a complex interplay between neuroinflammation, microglial activation and adaptive immunity in MPS disease.

Inhibition of selective adhesion molecules in treatment of inflammatory bowel disease

Lymphocyte infiltration into the intestinal tract in inflammatory bowel disease (IBD) is mediated by interaction between α4 integrin and its specific ligands. Development of monoclonal antibodies against α4 integrin allowed targeting of lymphocyte trafficking into the intestine as a novel therapeutic intervention. Natalizumab, vedolizumab, alicaforsen AJM300, rhuMAb β7, CCX282-B, and PF-00547,659 are few of monoclonal antibodies that have shown high promise in trials with the potential for more attractive benefit:risk ratio than currently available therapies. In this review, an attempt is made to underline the therapeutic potential and the safety of anti-adhesion molecule treatment in IBD.

Different parasite inocula determine the modulation of the immune response and outcome of experimental Trypanosoma cruzi infection

During infection, the host response develops effector mechanisms to combat the parasite. However, this response can become uncontrolled or regulated by mechanisms that modulate the inflammatory reaction. The number of parasites that infects the host, such as trypomastigotes in Chagas disease, may also influence immune activation and disease pathology. We evaluated the inflammation and immune regulation that follows Trypanosoma cruzi infection with low (300), intermediate (3000) or high (30000) parasite loads. Our results showed that the load of parasite inoculum influenced disease outcome: the higher the number of parasites in the inoculum, the lower were the survival rates. There was a strong association between parasitism and inflammatory infiltrate in the heart and the parasite inoculum determined cytokine interplay in this tissue, as shown by increased interferon-γ, tumour necrosis factor-α, interleukin-17 (IL-17) and IL-23 in the 300 and 30000 inoculum groups, higher IL-4 and IL-10 in the intermediate-inoculum mice, and elevated IL-6 production in the heart of mice in the 3000 and 30000 groups. The number of T cells and antigen-presenting cells was augmented in the infected groups, especially for the splenic CD4(+) CD25(+) regulatory T cells expressing CD45RB(low) , GITR, PD-1 and FoxP3 in the group with the highest inoculum. Interestingly, these mice also presented an apparent decrease in CD4(+) CD25(+) FoxP3(+) cells in the cardiac infiltrate, in contrast to the intermediate inoculum group, which showed elevated numbers of these regulatory leucocytes in the heart. Finally, our results demonstrated that parasite load during T. cruzi infection is linked to the response pattern that will result in parasite/inflammation control or tissue damage.

Characterisation of the T cell and dendritic cell repertoire in a murine model of mucopolysaccharidosis I (MPS I)

BACKGROUND

Mucopolysaccharidosis I (MPS I) is a metabolic disorder caused by α-L-Iduronidase (IDUA) deficiency, resulting in lysosomal accumulation of heparan (HS) and dermatan sulphate (DS). This has been reported in microglia, yet currently the effect of IDUA deficiency on T cells and dendritic cells (DC) and their functionality in disease pathogenesis remains unclear.

METHODS

Peripheral blood was collected from 3 month old C57BL/6 MPS I (n = 11) and wildtype (WT) (n = 6) mice. T cell and DC phenotype and functional characteristics were identified by flow cytometry.

RESULTS

MPS I mice exhibited a reduction in DC (p = <0.001) along with CD8+ cytotoxic (p = 0.01) and CD4+ T helper (p = 0.032) cells, compared to WT controls. MPS I DC displayed a significant decrease in cell surface CD123 (p = 0.02) and CD86 (p = 0.006) expression. Furthermore, CD45RB expression was significantly reduced on T helper cells in the MPS I population (p = 0.019).

CONCLUSION

We report a reduction in circulating DC and T cells in the MPS I mouse; indicative of adaptive immune dysfunction. DC reduction may occur in response to down-regulation of the IL-3 receptor (CD123), necessary for DC survival. We also report down-regulation of cell surface CD86, a molecule required for T cell co-stimulation. T helper cell down-regulation of CD45RB is redolent of an anti-inflammatory phenotype with poor proliferative capacity. The definitive causes of our findings and the consequences and role that these findings play in the pathogenesis of MPS are unclear, but may be in response to lysosomal storage of unmetabolized HS and DS.

Peripheral blood T lymphocyte subsets in children with congenital asplenia

The aim of the current study was to examine whether a congenital lack of the spleen changes distribution, state of activation and function of peripheral lymphocyte T subsets. Seven children with congenital asplenia (CA) aged 1.5-17 years and seven age-matched controls were tested. By triple-color flow cytometry we examined: (1) the expression of CD3(+), CD4(+), CD8(+), CD19(+), and CD56(+) on lymphocytes; (2) the distribution of CD45RA(+) and CD45RO(+) in CD4(+) and CD8(+); (3) the expression of CD27(+) in the CD4(+) and CD8(+) T-cell-bearing CD45RA(+), CD45RO(+), or CD45RB(+). Lymphocyte proliferative responses and cytokines production (IFN-gamma, IL-6, TNF-alfa, and IL-10) in anti-CD3-induced peripheral blood mononuclear cells were tested. The results indicate (1) a normal distribution of the basic lymphocyte subsets, (2) low CD3(+)/CD8(+) percentage but expressing CD8(+high) and non-significantly elevated CD4(+)/CD8(+) ratio, (3) CD45RA(+high) and CD27(+high) in the CD4(+) and CD8(+) T cell, and (4) CD45RB(+high) in the CD4(+) and CD45RO(+high) in the CD8(+). The distribution of CD27(+) in the CD45RA(+) and CD45RO(+) CD4(+) T cells remained unchanged. However, the percentage of CD8(+)/CD45RO(+)/CD27(+) T cells tended to be elevated. Altogether, these data indicate that CA is connected with (1) the presence CD4(+) T cells expressing the "naive" phenotype (CD45RA(+high) RB(+high) and CD27(+high)), (2) high numbers of activated CD8(+) T cells shifted toward the memory phenotype (CD45RO(+high)) but still showing high CD27(+) expression, which may indicate failure in T CD8(+) cytotoxic effectors differentiation, and (3) a tendency to the rather pro-inflammatory status of cells, low IL-10 expression, and suboptimal lymphocytes responses to mitogenic stimulation.

Impact of dietary gluten on regulatory T cells and Th17 cells in BALB/c mice

Dietary gluten influences the development of type 1 diabetes (T1D) and a gluten-free (GF) diet has a protective effect on the development of T1D. Gluten may influence T1D due to its direct effect on intestinal immunity; however, these mechanisms have not been adequately studied. We studied the effect of a GF diet compared to a gluten-containing standard (STD) diet on selected T cell subsets, associated with regulatory functions as well as proinflammatory Th17 cells, in BALB/c mice. Furthermore, we assessed diet-induced changes in the expression of various T cell markers, and determined if changes were confined to intestinal or non-intestinal lymphoid compartments. The gluten-containing STD diet led to a significantly decreased proportion of γδ T cells in all lymphoid compartments studied, although an increase was detected in some γδ T cell subsets (CD8⁺, CD103⁺). Further, it decreased the proportion of CD4⁺CD62L⁺ T cells in Peyer's patches. Interestingly, no diet-induced changes were found among CD4⁺Foxp3⁺ T cells or CD3⁺CD49b⁺cells (NKT cells) and CD3⁻CD49b⁺ (NK) cells. Mice fed the STD diet showed increased proportions of CD4⁺CD45RB^high+ and CD103⁺ T cells and a lower proportion of CD4⁺CD45RB^low+ T cells in both mucosal and non-mucosal compartments. The Th17 cell population, associated with the development of autoimmunity, was substantially increased in pancreatic lymph nodes of mice fed the STD diet. Collectively, our data indicate that dietary gluten influences multiple regulatory T cell subsets as well as Th17 cells in mucosal lymphoid tissue while fewer differences were observed in non-mucosal lymphoid compartments.

Markers of Inflammation and Lineage on Exfoliated Colonic Cells In Pediatric Inflammatory Bowel Disease

OBJECTIVES

The diagnosis (endoscopy, and biopsy) and continued clinical management of Inflammatory Bowel Disease (IBD), remain highly invasive, expensive, and inconvenient for the pediatric patient. The objective of this study was to see if colonocytes obtained from stools of subjects with IBD and normal controls would demonstrate higher levels of inflammatory markers (Cox 2 in CD45+ and CD45- cells) and if the inflammatory process and treatment effects would be reflected in an altered cytokine expression in the subjects compared to controls.

SETTING

Outpatient hospital based pediatric gastroenterology clinic.

METHODS AND MAIN OUTCOME MEASURES

Stool samples (~ 1 gm), were obtained from 18 children between the ages of 4 and 18 diagnosed with IBD, and from a normal first degree relative. Colonocytes were isolated using the Somatic Cell Sampling Recovery (SCSR) system and assessed for the expression of COX-2, CD-45, IgA, IgG, IL6, IL18, TGF β, TNF, and IL16β using flow cytometry. In addition, levels of COX-2 and cytokeratin 19 transcripts were measured by microwell plate hybridization assay.

RESULTS

Expression of COX-2 and co-expression of IgA and IgG were significantly higher in the IBD cases compared to the controls. In ulcerative colitis, the expression of COX-2 and co-expression of COX-2 and CD45 were greater than that in patients with Crohn's disease. In contrast, cells expressing IgA and IgG were higher in Crohn's. Subjects on immunosuppressants and/or anti-inflammatory medications, expressed significantly lower levels of COX-2 and IL-18 compared to those who were not on treatment.

CONCLUSIONS

This study indicates that the use of disease markers on exfoliated colonic cells can be used for non-invasive assessment of disease status, for follow-up of response to treatment and for forecasting flare-up of disease before its symptomatic manifestations.

Characteristic Immune Response in Peyer's Patch Cells Induced by Oral Administration of Bifidobacterium Components

We demonstrate immunomodulatory effects, especially those involving murine intestinal IgA secretion, in Peyer's patch cells following oral administration of Bifidobacterium immunomodulator (BIM) derived from sonicated B. pseudocatenulatum 7041. BALB/c mice were administered BIM orally for 7 consecutive days. The PP cells demonstrated upregulated secretion of total IgA including BIM-specific IgA following BIM administration. In observing the response of PP cells co-cultured with BIM, we found enhanced secretion of interferon-gamma (IFN-gamma) and interleukin (IL)-6 in the CD4(+) T cells. In contrast, IL-12 secretion by Thy1.2(-) PP cells was enhanced, but secretion of IFN-gamma, IL-5, and IL-6 was not significantly affected. Furthermore, the population of CD4(+) CD45RB(high) T cells in PP increased following oral administration of BIM. These data suggest that CD4(+) T cells were affected by BIM administration. Overall, the results show that oral administration of BIM induced CD4(+) PP cells to change their expression of cell surface antigen and cytokine production.

An imbalance of esophageal effector and regulatory T cell subsets in experimental eosinophilic esophagitis in mice

We recently reported a critical role for T cells in the induction of eosinophilic esophagitis (EE) in mice; however, the role of specific T cell subsets in disease pathogenesis is not yet understood. In the current study, we tested the hypothesis that allergen-induced EE develops in response to the disproportion of functionally different effector and regulatory T cells in the esophagus. Fluorescence-activated cell sorter analysis was performed to examine activated T cell subsets using the cell surface activation markers CD25 and CD69. A significant increase in activated CD4(+) and CD4(-) T cells was observed in the total esophageal cells isolated from the mouse model of EE. Furthermore, an imbalance in the effector and regulatory T cells was observed in the esophagus. The esophageal CD4(+)CD45RB(high) effector T cells in allergen-challenged mice increased compared with saline-challenged mice (65.4 +/- 3.6 x 10(3) to 44.8 +/- 4.2 x 10(3)), whereas CD4(+)CD45RB(low) mostly regulatory T cells decreased in allergen-challenged mice compared with saline-challenged mice (5.8 +/- 0.9 x 10(3) from 10.2 +/- 1.7 x 10(3)). The functional characteristics were examined by analysis of the pro- and anti-inflammatory cytokine profile of purified low and high CD4(+)CD45RB subsets from the spleen. Additionally, a significantly reduced interleukin (IL)-2 production by CD4(+)CD45RB(low) cells in allergen-challenged mice compared with saline-challenged mice was observed. The reduced IL-2 in the CD4(+)CD45RB(low) subset may be associated with reduction of CD4(+)CD45RB(low) subset. In conclusion, our results suggest that local regulatory interaction of CD45RB(high) and CD45RB(low) CD4(+) T cells may be required for protective and pathogenic immunity in EE.

Regulatory T cells in inflammatory bowel disease

PURPOSE OF REVIEW

The intestinal immune system must orchestrate a complex balance between proinflammatory and anti-inflammatory responses to luminal antigens, and disruptions in this balance can result in inflammatory bowel disease (IBD). This review explores recent data that elucidate the role of regulatory T cells (Tregs) in the pathogenesis of IBD in mice and humans.

RECENT FINDINGS

Data from murine models of colitis implicate several novel mechanisms critical to Treg function and generation including the inhibitory cytokine interleukin-35, pericellular adenosine generation and cytokine deprivation-induced apoptosis. Although Tregs are essential in mice for the maintenance of intestinal homeostasis, their role in human IBD remains unclear. Patients with IBD appear to have relatively reduced numbers of Tregs in the blood and colon; however, Tregs from these patients are functional in vitro.

SUMMARY

Tregs are important for the maintenance of intestinal self-tolerance and will likely prove to be an important avenue for therapeutic manipulation in IBD.

CD46-induced immunomodulatory CD4+ T cells express the adhesion molecule and chemokine receptor pattern of intestinal T cells

Tissue homing of activated T cells is typically mediated through their specific integrin and chemokine receptor repertoire. Activation of human primary CD4(+) T cells in the presence of CD46 cross-linking induces the development of a distinct immunomodulatory T cell population characterized by high IL-10/granzyme B production. How these regulatory T cells (Tregs) migrate/home to specific tissue sites is not understood. In this study, we determined the adhesion protein and chemokine receptor expression pattern on human CD3/CD46-activated peripheral blood CD4(+) T cells. CD3/CD46-activated, but not CD3/CD28-activated, T cells up-regulate the integrin alpha(4)beta(7). The interaction of alpha(4)beta(7) with its ligand mucosal addressin cell adhesion molecule 1 (MAdCAM-1) mediates homing or retention of T cells to the intestine. CD3/CD46-activated Tregs adhere to/roll on MAdCAM-1-expressing HeLa cells, similar to T cells isolated from the human lamina propria (LP). This interaction is inhibited by silencing MAdCAM-1 expression in HeLa cells or by the addition of blocking Abs to beta(7). CD46 activation of T cells also induced the expression of the surface-bound cytokine LIGHT and the chemokine receptor CCR9, both marker constitutively expressed by gut LP-resident T cells. In addition, we found that approximately 10% of the CD4(+) T lymphocytes isolated from the LP of patients undergoing bariatric surgery contain T cells that spontaneously secrete a cytokine pattern consistent with that from CD46-activated T cells. These data suggest that CD46-induced Tregs might play a role in intestinal immune homeostasis where they could dampen unwanted effector T cell responses through local IL-10/granzyme B production.

Both Th1 and Th17 are immunopathogenic but differ in other key biological activities

The role of Th17 lymphocytes in immunopathogenic processes has been well established, but little is known about their basic cell features. In this study, we compared polarized Th1 and Th17 for key biological activities related to pathogenicity and trafficking. Th1 and Th17 lineages were derived from TCR-transgenic CD4 murine cells specific against hen egg lysozyme. When adoptively transferred into mice expressing hen egg lysozyme in their eyes, both Th1 and Th17 induced ocular inflammation but with slight differences in histological pathology. PCR analysis revealed selective expression of IFN-gamma or IL-17 in eyes of Th1 or Th17 recipients, respectively. Additionally, Th1 and Th17 were found to differ in three other key activities: 1) Th17 cells were inferior to Th1 cells in their capacity to trigger massive lymphoid expansion and splenomegaly; 2) the proportion of Th1 cells among infiltrating cells in inflamed recipient eyes declined rapidly, becoming a minority by day 7, whereas Th17 cells remained in the majority throughout this period; and 3) remarkable differences were noted between Th1 and Th17 cells in their expression of certain surface markers. In particular, reactivated Th1 expressed higher levels of CD49d and alpha(4)beta(7) (mucosal homing) in vitro and higher levels of CXCR3 (Th1 trafficking) in vivo. Reactivated Th17, however, expressed higher levels of alpha(E)beta(7) (epithelial tissue homing) and CD38 (activation, maturation and trafficking) in vitro, but in vivo Th17 expressed higher levels of alpha(4)beta(7) and CCR6 (lymphocyte trafficking). These data reveal that Th1 and Th17 cells differ in several key biological activities influencing migration and pathogenic behavior during inflammatory disease.

The myeloid differentiation factor 88 (MyD88) is required for CD4+ T cell effector function in a murine model of inflammatory bowel disease

Abnormal T cell responses to commensal bacteria are involved in the pathogenesis of inflammatory bowel disease. MyD88 is an essential signal transducer for TLRs in response to the microflora. We hypothesized that TLR signaling via MyD88 was important for effector T cell responses in the intestine. TLR expression on murine T cells was examined by flow cytometry. CD4(+)CD45Rb(high) T cells and/or CD4(+)CD45Rb(low)CD25(+) regulatory T cells were isolated and adoptively transferred to RAG1(-/-) mice. Colitis was assessed by changes in body weight and histology score. Cytokine production was assessed by ELISA. In vitro proliferation of T cells was assessed by [(3)H]thymidine assay. In vivo proliferation of T cells was assessed by BrdU and CFSE labeling. CD4(+)CD45Rb(high) T cells expressed TLR2, TLR4, TLR9, and TLR3, and TLR ligands could act as costimulatory molecules. MyD88(-/-) CD4(+) T cells showed decreased proliferation compared with WT CD4(+) T cells both in vivo and in vitro. CD4(+)CD45Rb(high) T cells from MyD88(-/-) mice did not induce wasting disease when transferred into RAG1(-/-) recipients. Lamina propria CD4(+) T cell expression of IL-2 and IL-17 and colonic expression of IL-6 and IL-23 were significantly lower in mice receiving MyD88(-/-) cells than mice receiving WT cells. In vitro, MyD88(-/-) T cells were blunted in their ability to secrete IL-17 but not IFN-gamma. Absence of MyD88 in CD4(+)CD45Rb(high) cells results in defective T cell function, especially Th17 differentiation. These results suggest a role for TLR signaling by T cells in the development of inflammatory bowel disease.

1,25-dihydroxyvitamin D3 and dexamethasone increase interleukin-10 production in CD4+ T cells from patients with Crohn's disease

BACKGROUND AND AIM

In Crohn's disease (CD), epidemiological data and animal studies suggest that vitamin D (vitD) has protective immune-modulating properties. 1,25-dihydroxyvitamin D3 and dexamethasone (DEX) induce interleukin (IL)-10 productions in healthy controls (HC) T cells. We studied if 1,25-dihydroxyvitamin D3 with and without DEX could induce IL-10 production, downregulate pro-inflammatory Interferon (IFN)-gamma and Tumor Necrosis Factor (TNF)-alpha production, and influence cell kinetics in peripheral CD4+ T cells from CD patients.

METHODS

CD4+ T cells were separated from peripheral blood from CD patients and HC. Cells were activated by anti-CD3 and anti-CD28 in the presence of 1,25-dihydroxyvitamin D3 and/or DEX. Cytokine levels, proliferation, and apoptosis were measured following 7 days of culture.

RESULTS

In T cells from CD patients, 1,25-dihydroxyvitamin D3 and DEX increased IL-10 production from a median of 0.08 ng/ml to 0.2 ng/ml (p<0.01) and downregulated IFN-gamma production from 8.3 ng/ml to 3.1 ng/ml (p<0.01). The induced IL-10 increase in cultures from HC (0.2 ng/ml to 1.0 ng/ml, p<0.01) was significantly higher than in CD patients (p<0.05). In CD cultures, the IL-4 production increased from 0.3 ng/ml to 0.5 ng/ml (p<0.01) and IL-6 production from 2.5 ng/ml to 6.1 ng/ml (p<0.05). Similar changes in cytokine levels were observed with 1,25-dihydroxyvitamin D3 independently of DEX. In addition, 1,25-dihydroxyvitamin D3 and DEX decreased proliferation and reduced viability of T cells.

CONCLUSION

We found that 1,25-dihydroxyvitamin D3 with and without DEX stimulation increased IL-10 and reduced IFN-gamma production. These findings suggest that vitD may play a therapeutic role in CD.

Crohn's disease intestinal CD4+ T cells have impaired interleukin-10 production which is not restored by probiotic bacteria

OBJECTIVE

Crohn's disease (CD) has been associated with low mucosal interleukin (IL)-10 production, but the mechanism behind this deficiency remains unclear. The aim of this study was to investigate IL-10 and interferon (IFN)-gamma production in intestinal CD4+ T cells from CD patients and healthy volunteers (HV) and to examine how this was affected by bacterial products and the presence or absence of autologous dendritic cells.

MATERIAL AND METHODS

We cultured intestinal CD4+ T cells from CD patients (n=9) and HV (n=6) and differentiated dendritic cells from their peripheral monocytes. Intestinal T cells were stimulated with Lactobacillus strains or autologous intestinal bacteria in the presence or absence of dendritic cells. IL-10 and IFN-gamma were measured on day 4.

RESULTS

When there were autologous dendritic cells present, CD intestinal T cells produced high levels of IFN-gamma (mean 6.4 ng/ml+/-standard error of the mean 1.1 ng/ml) but low levels of IL-10 (0.7 ng/ml+/-0.1 ng/ml). In contrast, HV intestinal T cells produced less IFN-gamma (3.9 ng/ml+/-0.8 ng/ml, p=0.06) and more IL-10 (4.6 ng/ml+/-0.9 ng/ml, p=0.0001) than CD intestinal T cells. Co-culture with Lactobacilli failed to revert this imbalance in CD, but tended to do so in HV. When there were no dendritic cells, CD intestinal T cells responded to autologous bacteria with an increased IFN-gamma production (2.3+/-1.3 ng/ml) compared with HV intestinal T cells (0.3+/-0.2 ng/ml).

CONCLUSIONS

Crohn's disease intestinal CD4+ T cells display a pro-inflammatory cytokine profile with impaired production of the regulatory cytokine IL-10. Tolerogenic bacteria (Lactobacilli) failed to restore this regulatory defect.

Differential angiogenic regulation of experimental colitis

Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders of the intestinal tract with unknown multifactorial etiology that, among other things, result in alteration and dysfunction of the intestinal microvasculature. Clinical observations of increased colon microvascular density during IBD have been made. However, there have been no reports investigating the physiological or pathological importance of angiogenic stimulation during the development of intestinal inflammation. Here we report that the dextran sodium sulfate and CD4+CD45RBhigh T-cell transfer models of colitis stimulate angiogenesis that results in increased blood vessel density concomitant with increased histopathology, suggesting that the neovasculature contributes to tissue damage during colitis. We also show that leukocyte infiltration is an obligatory requirement for the stimulation of angiogenesis. The angiogenic response during experimental colitis was differentially regulated in that the production of various angiogenic mediators was diverse between the two models with only a small group of molecules being similarly controlled. Importantly, treatment with the anti-angiogenic agent thalidomide or ATN-161 significantly reduced angiogenic activity and associated tissue histopathology during experimental colitis. Our findings identify a direct pathological link between angiogenesis and the development of experimental colitis, representing a novel therapeutic target for IBD.

N/A

N/A

Infliximab for induction and maintenance therapy for ulcerative colitis

BACKGROUND

Infliximab, a chimeric monoclonal antibody directed against tumor necrosis factor alpha, is an established treatment for Crohn's disease but not ulcerative colitis.

METHODS

Two randomized, double-blind, placebo-controlled studies--the Active Ulcerative Colitis Trials 1 and 2 (ACT 1 and ACT 2, respectively)--evaluated the efficacy of infliximab for induction and maintenance therapy in adults with ulcerative colitis. In each study, 364 patients with moderate-to-severe active ulcerative colitis despite treatment with concurrent medications received placebo or infliximab (5 mg or 10 mg per kilogram of body weight) intravenously at weeks 0, 2, and 6 and then every eight weeks through week 46 (in ACT 1) or week 22 (in ACT 2). Patients were followed for 54 weeks in ACT 1 and 30 weeks in ACT 2.

RESULTS

In ACT 1, 69 percent of patients who received 5 mg of infliximab and 61 percent of those who received 10 mg had a clinical response at week 8, as compared with 37 percent of those who received placebo (P<0.001 for both comparisons with placebo). A response was defined as a decrease in the Mayo score of at least 3 points and at least 30 percent, with an accompanying decrease in the subscore for rectal bleeding of at least 1 point or an absolute rectal-bleeding subscore of 0 or 1. In ACT 2, 64 percent of patients who received 5 mg of infliximab and 69 percent of those who received 10 mg had a clinical response at week 8, as compared with 29 percent of those who received placebo (P<0.001 for both comparisons with placebo). In both studies, patients who received infliximab were more likely to have a clinical response at week 30 (P< or =0.002 for all comparisons). In ACT 1, more patients who received 5 mg or 10 mg of infliximab had a clinical response at week 54 (45 percent and 44 percent, respectively) than did those who received placebo (20 percent, P<0.001 for both comparisons).

CONCLUSIONS

Patients with moderate-to-severe active ulcerative colitis treated with infliximab at weeks 0, 2, and 6 and every eight weeks thereafter were more likely to have a clinical response at weeks 8, 30, and 54 than were those receiving placebo. (ClinicalTrials.gov numbers, NCT00036439 and NCT00096655.)

Complement-induced regulatory T cells suppress T-cell responses but allow for dendritic-cell maturation

Concurrent activation of the T-cell receptor (TCR) and complement regulator CD46 on human CD4+ T lymphocytes induces Tr1-like regulatory T cells that suppress through IL-10 secretion bystander T-cell proliferation. Here we show that, despite their IL-10 production, CD46-induced T-regulatory T cells (Tregs) do not suppress the activation/maturation of dendritic cells (DCs). DC maturation by complement/CD46-induced Tregs is mediated through simultaneous secretion of GM-CSF and soluble CD40L, factors favoring DC differentiation and reversing inhibitory effects of IL-10. Thus, CD46-induced Tregs produce a distinct cytokine profile that inhibits T-cell responses but leaves DC activation unimpaired. Such "DC-sparing" Tregs could be desirable at host/environment interfaces such as the gastrointestinal tract where their specific cytokine profile provides a mechanism that ensures unresponsiveness to commensal bacteria while maintaining reactivity to invading pathogens.