Basal lymphoid aggregates in ulcerative colitis colon: a site for regulatory T cell action

Definitions of Histological Abnormalities in Inflammatory Bowel Disease: an ECCO Position Paper

Histological assessment of endoscopic biopsies in inflammatory bowel disease [IBD] plays an important role in clinical management, investigative studies, and clinical trials. Scoring schemes consisting of multiple histological items and offering considerable precision are widely available. However, definitions of histological abnormalities are often inconsistent. Furthermore, interobserver variability for their recognition and assessment may be high. The European Crohn's and Colitis Organisation [ECCO] formed an expert panel to explore definitions of histological abnormalities in IBD, with the aim of improving the quality of diagnosis and facilitating development of scoring schemes. The process confirmed that the current definitions often have no evidence base and vary between sources. Using available evidence and expert knowledge, the panel produced a series of ECCO consensus position statements on histological features in IBD.

Detection of lymph node metastasis in colon cancer by ectopically expressed fibroblast markers FOXQ1 and THBS2

Introduction

Approximately 25% of colon cancer (CC) patients having curative surgery will relapse. Therefore, it is crucial to identify patients with increased recurrence risk to offer them adjuvant chemotherapy. Three markers with prominent expression in fibroblasts: forkhead box Q1 (FOXQ1), matrix metalloproteinase-11 (MMP11), and thrombospondin-2 (THBS2), and the fibroblast expressed chemokine CXCL12 were selected for studies because of the critical role of fibroblasts in the microenvironment of the tumor.

Methods

The expression levels of the biomarkers were assessed in primary CC tumors, lymph nodes of CC patients and controls, and CC cell lines at mRNA and protein levels by real-time qRT-PCR and immunohistochemistry, respectively.

Results

FOXQ1, MMP11, and THBS2 mRNAs were expressed at significantly higher levels in primary tumors compared to normal colon (P=0.002, P<0.0001, and P<0.0001, respectively). In contrast, CXCL12 mRNA levels were higher in normal colon tissue. FOXQ1, MMP11, and THBS2 levels were also expressed at significantly higher levels in metastasis-positive lymph nodes compared to both metastasis-negative- and control nodes (P<0.0001/P=0.002, P<0.0001/P<0.0001, and P<0.0001/P<0.0001, respectively). Immuno-morphometry revealed that 30-40% of the tumor cells expressed FOXQ1, MMP11, and THBS2. FOXQ1 and THBS2 were barely detected in normal colon epithelium (P<0.0001), while MMP11 was expressed in normal colon epithelium at high levels.

Discussion

We conclude that CC tumor cells show ectopic expression of FOXQ1 and THBS2 possibly making these tumor cells independent of fibroblast cell support. The high expression levels of these two biomarkers in metastatic lymph nodes suggest that they are potential indicators of patients at risk for recurrence.

Enhanced oxidative phosphorylation of IgG plasma cells can contribute to hypoxia in the mucosa of active ulcerative colitis

Mucosal hypoxia is detected in the mucosa of ulcerative colitis (UC), however the mechanism and the cause of hypoxia is not fully understood, while a dense infiltration of plasma cells is observed in the inflamed mucosa of UC. When differentiating from a B cell to a plasma cell, the energy metabolism dramatically shifts from glycolysis to oxidative phosphorylation, which results in a large amount of oxygen consumption of the plasma cell. We hypothesized that the plasma cell infiltration into the inflamed mucosa contributes to the mucosal hypoxia in UC in part. We examined the association between mucosal hypoxia and plasma cell infiltration in UC. More IgG plasma cells (but not IgA plasma cells) were distributed, and the nuclear and cell sizes were enlarged in hypoxic mucosa compared to normoxic mucosa in UC. Oxidative phosphorylation signature genes of these IgG plasma cells were markedly upregulated compared to those of other lymphoid cells infiltrating the lamina propria of inflamed mucosa of UC. Enlarged IgG plasma cells, which increase in number in the inflamed mucosa of UC, can be related to the hypoxic state of the inflamed mucosa of UC.

Clinical Significance of Stem Cell Biomarkers EpCAM, LGR5 and LGR4 mRNA Levels in Lymph Nodes of Colon Cancer Patients

The significance of cancer stem cells (CSCs) in initiation and progression of colon cancer (CC) has been established. In this study, we investigated the utility of measuring mRNA expression levels of CSC markers EpCAM, LGR5 and LGR4 for predicting survival outcome in surgically treated CC patients. Expression levels were determined in 5 CC cell lines, 66 primary CC tumors and 382 regional lymph nodes of 121 CC patients. Prognostic relevance was determined using Kaplan-Meier survival and Cox regression analyses. CC patients with lymph nodes expressing high levels of EpCAM, LGR5 or LGR4 (higher than a clinical cutoff of 0.07, 0.06 and 2.558 mRNA copies/18S rRNA unit, respectively) had a decreased mean survival time of 32 months for EpCAM and 42 months for both LGR5 and LGR4 at a 12-year follow-up (p = 0.022, p = 0.005 and p = 0.011, respectively). Additional patients at risk for recurrence were detected when LGR5 was combined with the biomarkers CXCL17 or CEA plus CXCL16. In conclusion, the study underscores LGR5 as a particularly useful prognostic biomarker and illustrates the strength of combining biomarkers detecting different subpopulations of cancer cells and/or cells in the tumor microenvironment for predicting recurrence.

Clinical Significance of Stem Cell Biomarkers EpCAM, LGR5 and LGR4 mRNA Levels in Lymph Nodes of Colon Cancer Patients

The significance of cancer stem cells (CSCs) in initiation and progression of colon cancer (CC) has been established. In this study, we investigated the utility of measuring mRNA expression levels of CSC markers EpCAM, LGR5 and LGR4 for predicting survival outcome in surgically treated CC patients. Expression levels were determined in 5 CC cell lines, 66 primary CC tumors and 382 regional lymph nodes of 121 CC patients. Prognostic relevance was determined using Kaplan-Meier survival and Cox regression analyses. CC patients with lymph nodes expressing high levels of EpCAM, LGR5 or LGR4 (higher than a clinical cutoff of 0.07, 0.06 and 2.558 mRNA copies/18S rRNA unit, respectively) had a decreased mean survival time of 32 months for EpCAM and 42 months for both LGR5 and LGR4 at a 12-year follow-up (p = 0.022, p = 0.005 and p = 0.011, respectively). Additional patients at risk for recurrence were detected when LGR5 was combined with the biomarkers CXCL17 or CEA plus CXCL16. In conclusion, the study underscores LGR5 as a particularly useful prognostic biomarker and illustrates the strength of combining biomarkers detecting different subpopulations of cancer cells and/or cells in the tumor microenvironment for predicting recurrence.

CD98-induced CD147 signaling stabilizes the Foxp3 protein to maintain tissue homeostasis

Regulatory T cell (Treg) stability is necessary for the proper control of immune activity and tissue homeostasis. However, it remains unclear whether Treg stability must be continually reinforced or is established during development under physiological conditions. Foxp3 has been characterized as a central mediator of the genetic program that governs Treg stability. Here, we demonstrate that to maintain Foxp3 protein expression, Tregs require cell-to-cell contact, which is mediated by the CD147-CD98 interaction. As Tregs are produced, CD147, which is expressed on their surface, is stimulated by CD98, which is widely expressed in the physiological environment. As a result, CD147's intracellular domain binds to CDK2 and retains it near the membrane, leading to Foxp3 dephosphorylation and the prevention of Foxp3 degradation. In addition, the optimal distribution of Foxp3+ Tregs under both pathological and physiological conditions depends on CD98 expression. Thus, our study provides direct evidence that Foxp3-dependent Treg stability is reinforced in the periphery by the interaction between CD147 and CD98 in the surrounding environment. More importantly, Tregs with high CD147 expression effectively inhibit inflammatory responses and maintain Foxp3 stability, which has guiding significance for the application of Tregs in immunotherapy.

The myeloid cell biomarker EMR1 is ectopically expressed in colon cancer

OBJECTIVE

The microenvironment of colon cancer (CC) is heterogeneous including cells of myeloid lineage affecting tumor growth and metastasis. Two functional subtypes of myeloid cells have been identified; one (M1) is tumor-inhibitory and the other one (M2) is tumor-promoting. Whether the three myeloid markers EMR1, CD206 and CD86 are expressed only in the infiltrating myeloid cells or also in the tumor cells was investigated.

METHODS

Expression of the myeloid markers was investigated in CC at the mRNA and protein levels in primary tumors and lymph nodes. mRNA expression was also determined in 5 CC cell lines. Protein expression was investigated by two-color immunofluorescence and consecutive-sections-immune-staining combined with morphometry using specific antibodies for the myeloid cell markers and the epithelial cell markers CEACAM5 and EpCAM.

RESULTS

EMR1 and CD86, but not CD206, mRNA levels were significantly higher in CC primary tumors compared to apparently normal colon tissue (P <  0.0001). EMR1 mRNA levels were significantly higher in both hematoxylin-eosin positive (H&E(+)) and H&E(-) lymph nodes of CC patients compared to control nodes (P = 0.03 and P = 0.01, respectively). EMR1 and CD206 mRNAs were expressed in 4/5 and 5/5 CC cell lines, respectively, while CD86 mRNA was not expressed. Immuno-morphometry revealed that about 20% of the tumor cells expressed EMR1 and CD206. Positive cells were tumor cells as revealed by anti-CEACAM5 and anti-EpCAM staining. The number of EMR1, CD206 and CD86 positive cells were significantly increased in CC primary tumors compared to normal colon tissue (P <  0.0001). However, CD206 was also expressed in normal colonocytes. Only EMR1 showed significantly increased numbers of positive tumor cells in H&E(+) nodes compared to H&E(-) nodes (P = 0.001). EMR1 expression in CC tumor cells correlated with CXCL17 expressing tumor cells.

CONCLUSION

EMR1, like the chemokine CXCL17, is ectopically expressed in colon cancer possibly in the same cancer cells.

Human gut-associated lymphoid tissues (GALT); diversity, structure, and function

Gut-associated lymphoid tissues (GALT) are the key antigen sampling and adaptive immune inductive sites within the intestinal wall. Human GALT includes the multi-follicular Peyer's patches of the ileum, the vermiform appendix, and the numerous isolated lymphoid follicles (ILF) which are distributed along the length of the intestine. Our current understanding of GALT diversity and function derives primarily from studies in mice, and the relevance of many of these findings to human GALT remains unclear. Here we review our current understanding of human GALT diversity, structure, and composition as well as their potential for regulating intestinal immune responses during homeostasis and inflammatory bowel disease (IBD). Finally, we outline some key remaining questions regarding human GALT, the answers to which will advance our understanding of intestinal immune responses and provide potential opportunities to improve the treatment of intestinal diseases.

Identification, isolation and analysis of human gut-associated lymphoid tissues

Gut-associated lymphoid tissues (GALTs) comprise key intestinal immune inductive sites, including the Peyer's patches of the small intestine and different types of isolated lymphoid follicle (ILF) found along the length of the gut. Our understanding of human GALT is limited due to a lack of protocols for their isolation. Here we describe a technique that, uniquely among intestinal cell isolation protocols, allows identification and isolation of all human GALT, as well as GALT-free intestinal lamina propria (LP). The technique involves the mechanical separation of intestinal mucosa from the submucosa, allowing the identification and isolation of submucosal ILF (SM-ILF), LP-embedded mucosal ILF (M-ILF) and LP free of contaminating lymphoid tissue. Individual SM-ILF, M-ILF and Peyer's patch follicles can be subsequently digested for downstream cellular and molecular characterization. The technique, which takes 4-10 h, will be useful for researchers interested in intestinal immune development and function in health and disease.

Evaluating macrophage migration inhibitory factor 1 expression as a prognostic biomarker in colon cancer

OBJECTIVE

Several studies indicate that macrophage migration inhibitory factor 1 plays a role for tumor progression in colon cancer. We investigated whether determination of migration inhibitory factor 1 mRNA expression levels in lymph nodes of colon cancer patients could be used as a prognostic marker.

METHODS

Expression levels of migration inhibitory factor 1 and carcinoembryonic antigen mRNAs were assessed in primary tumors and regional lymph nodes of 123 colon cancer patients (stages I-IV), and in colon cancer- and immune cell lines using quantitative reverse transcriptase-polymerase chain reaction. Expression of migration inhibitory factor 1 protein was investigated by two-color immunohistochemistry and immunomorphometry.

RESULTS

Migration inhibitory factor 1 mRNA was expressed at 60 times higher levels in primary colon cancer tumors compared to normal colonic tissue (medians 8.2 and 0.2 mRNA copies/18S rRNA unit; p < .0001). A highly significant difference in mRNA expression levels was found between hematoxylin-eosin positive lymph nodes and hematoxylin-eosin negative lymph nodes (p < .0001). Migration inhibitory factor 1 and carcinoembryonic antigen proteins were simultaneously expressed in many colon cancer-tumor cells. Kaplan-Meier survival model and hazard ratio analysis, using a cutoff level at 2.19 mRNA copies/18S rRNA unit, revealed that patients with lymph nodes expressing high levels of migration inhibitory factor 1 mRNA had a 3.5-fold (p = .04) higher risk for recurrence, associated with a small, but significant, difference in mean survival time (7 months, p = .03) at 12 years of follow-up.

CONCLUSION

Although migration inhibitory factor 1 mRNA expression levels were related to severity of disease and lymph node analysis revealed that colon cancer patients with high levels had a shorter survival time after surgery than those with low levels, the difference was small and probably not useful in clinical practice.

The Chemokine CXCL16 Is a New Biomarker for Lymph Node Analysis of Colon Cancer Outcome

Chemokines are important in the development and progression of tumors. We investigated the expression of CXCL14 and CXCL16 in colon cancer. Expression of mRNA was assessed in primary tumors and lymph nodes and CXCL16 mRNA levels were correlated to patient's survival. Protein expression was investigated by two-color immunofluorescence and immunomorphometry. CXCL14 and CXCL16 mRNA levels and protein expression were significantly higher in colon cancer primary tumors compared to apparently normal colon tissue. Positive cells were tumor cells, as revealed by anti-CEA and anti-EpCAM staining. CXCL16, but not CXCL14, mRNA levels were significantly higher in hematoxylin and eosin positive (H&E(+)) compared to H&E(-) colon cancer lymph nodes or control nodes (P < 0.0001). CXCL16 mRNA was expressed in 5/5 colon cancer cell lines while CXCL14 was expressed significantly in only one. Kaplan-Meier analysis revealed that colon cancer patients with lymph nodes expressing high or very high levels (7.2 and 11.4 copies/18S rRNA unit, respectively) of CXCL16 mRNA had a decreased mean survival time of 30 and 46 months at the 12-year follow-up (P = 0.04, P = 0.005, respectively). In conclusion, high expression of CXCL16 mRNA in regional lymph nodes of colon cancer patients is a sign of a poor prognosis.

Utility of G protein-coupled receptor 35 expression for predicting outcome in colon cancer

The utility of mRNA and protein determinations of G protein-coupled receptor 35, that is, GPR35a (GPR35 V1) and GPR35b (GPR35 V2/3), as indicators of outcome for colon cancer patients after curative surgery was investigated. Expression levels of V1 and V2/3 GPR35, carcinoembryonic antigen and CXCL17 mRNAs were assessed in primary tumours and regional lymph nodes of 121 colon cancer patients (stage I-IV), colon cancer cell lines and control colon epithelial cells using real-time quantitative reverse transcriptase-polymerase chain reaction. Expression of G protein-coupled receptor 35 was investigated by two-colour immunohistochemistry and immunomorphometry. GPR35 V2/3 mRNA, but not V1 mRNA, was expressed in colon cancer cell lines, primary colon tumours and control colon epithelial cells. Haematoxylin and eosin positive (H&E(+)), but not H&E(-), lymph nodes expressed high levels of GPR35 V2/3 mRNA (P<0.0001). GPR35b and carcinoembryonic antigen proteins were simultaneously expressed in many colon cancer tumour cells. Kaplan-Meier and hazard ratio analysis revealed that patients with lymph nodes expressing high levels of GPR35 V2/3 mRNA and, in particular, in the group of patients with lymph nodes also expressing carcinoembryonic antigen mRNA, had a short disease-free survival time, 67 months versus 122 months at 12-year follow-up (difference: 55 months, P = 0.001; hazard ratio: 3.6, P = 0.002). In conclusion, high level expression of G protein-coupled receptor 35 V2/3 mRNA in regional lymph nodes of colon cancer patients is a sign of poor prognosis.

Lymph node CXCL17 messenger RNA: A new prognostic biomarker for colon cancer

Lymph node metastasis is the most important prognostic characteristic of colorectal cancer. Carcinoembryonic antigen messenger RNA was shown to detect tumor cells that have disseminated to lymph nodes of colorectal cancer patients and to be at least as good as the hematoxylin and eosin method to predict survival in colorectal cancer patients. CXCL17 was recently shown to be ectopically expressed in colon cancer tumors. Therefore, CXCL17 may serve as prognostic marker alone or in combination with carcinoembryonic antigen. CXCL17 and carcinoembryonic antigen messenger RNA levels were determined using quantitative reverse transcription polymerase chain reaction with RNA copy standard in 389 lymph nodes of 120 colon cancer patients (stages I-IV) and 67 lymph nodes of 12 control patients with inflammatory bowel disease as well as in 68 primary tumors and 30 normal colon tissue samples. Lymph nodes of colon cancer patients were analyzed for CXCL17 and carcinoembryonic antigen protein expression by immunohistochemistry. CXCL17 messenger RNA was expressed in primary tumors at high levels, while it was barely detected in normal colon tissue ( p < 0.0001). Similarly, CXCL17 messenger RNA levels were significantly higher in hematoxylin- and eosin-positive (hematoxylin and eosin (+)) lymph nodes compared to hematoxylin- and eosin-negative nodes ( p < 0.0001). CXCL17 messenger RNA levels were investigated in lymph nodes grouped according to carcinoembryonic antigen messenger RNA levels: low (-), intermediate (int), and high (+). CXCL17 messenger RNA levels were higher in the carcinoembryonic antigen (int) and carcinoembryonic antigen (+) groups compared to the carcinoembryonic antigen (-) group ( p = 0.03 and p < 0.0001, respectively). In lymph nodes of stage III and IV patients, CXCL17 messenger RNA levels correlated with carcinoembryonic antigen messenger RNA levels ( p < 0.0001, r = 0.56 and p = 0.0002, r = 0.66, respectively). Staining of consecutive lymph node sections for CXCL17 and carcinoembryonic antigen demonstrated that the same cells expressed both proteins. Altogether, these results indicate that CXCL17 in lymph nodes is expressed by tumor cells. Patients were grouped according to the CXCL17 messenger RNA levels in the highest lymph node with low levels (-) and high levels (+). CXCL17(+) colon cancer patients showed 2.8-3.6 fold increased risk for recurrence ( p = 0.03) and decreased mean disease-free survival time of 8 months compared to CXCL17(-) colon cancer patients ( p = 0.03). CXCL17(+) carcinoembryonic antigen (int) colon cancer patients showed increased risk for recurrence by 8.3 fold ( p = 0.04) and decreased mean disease-free survival time of 46 months compared to CXCL17(-) carcinoembryonic antigen (int) colon cancer patient at follow-up after 12 years ( p = 0.02). The presence of tumor cells expressing CXCL17 in regional lymph nodes is a sign of poor prognosis. Analysis of CXCL17 messenger RNA is particularly useful to detect less differentiated colon cancer tumors expressing relatively low carcinoembryonic antigen messenger RNA levels. Thus, CXCL17 messenger RNA in combination with carcinoembryonic antigen messenger RNA may be used as a complementary tool to the hematoxylin and eosin method for detection of poorly differentiated, aggressive tumors.

Ectopic expression of the chemokine CXCL17 in colon cancer cells

Background:

The novel chemokine CXCL17 acts as chemoattractant for monocytes, macrophages and dendritic cells. CXCL17 also has a role in angiogenesis of importance for tumour development.

Methods:

Expression of CXCL17, CXCL10, CXCL9 and CCL2 was assessed in primary colon cancer tumours, colon carcinoma cell lines and normal colon tissue at mRNA and protein levels by real-time qRT–PCR, immunohistochemistry, two-colour immunofluorescence and immunomorphometry.

Results:

CXCL17 mRNA was expressed at 8000 times higher levels in primary tumours than in normal colon (P<0.0001). CXCL17 protein was seen in 17.2% of cells in tumours as compared with 0.07% in normal colon (P=0.0002). CXCL10, CXCL9 and CCL2 mRNAs were elevated in tumours but did not reach the levels of CXCL17. CXCL17 and CCL2 mRNA levels were significantly correlated in tumours. Concordant with the mRNA results, CXCL10- and CXCL9-positive cells were detected in tumour tissue, but at significantly lower numbers than CXCL17. Two-colour immunofluorescence and single-colour staining of consecutive sections for CXCL17 and the epithelial cell markers carcinoembryonic antigen and BerEP4 demonstrated that colon carcinoma tumour cells indeed expressed CXCL17.

Conclusions:

CXCL17 is ectopically expressed in primary colon cancer tumours. As CXCL17 enhances angiogenesis and attracts immune cells, its expression could be informative for prognosis in colon cancer patients.

IL-15 functions as a danger signal to regulate tissue-resident T cells and tissue destruction

In this Opinion article, we discuss the function of tissues as a crucial checkpoint for the regulation of effector T cell responses, and the notion that interleukin-15 (IL-15) functions as a danger molecule that communicates to the immune system that the tissue is under attack and poises it to mediate tissue destruction. More specifically, we propose that expression of IL-15 in tissues promotes T helper 1 cell-mediated immunity and provides co-stimulatory signals to effector cytotoxic T cells to exert their effector functions and drive tissue destruction. Therefore, we think that IL-15 contributes to tissue protection by promoting the elimination of infected cells but that when its expression is chronically dysregulated, it can promote the development of complex T cell-mediated disorders associated with tissue destruction, such as coeliac disease and type 1 diabetes.

Reciprocal regulation of lymphoid tissue development in the large intestine by IL-25 and IL-23

Isolated lymphoid follicles (ILFs) develop after birth in the small and large intestines (SI and LI) and represent a dynamic response of the gut immune system to the microbiota. Despite their similarities, ILF development in the SI and LI differs on a number of levels. We show that unlike ILF in the SI, the microbiota inhibits ILF development in the colon as conventionalization of germ-free mice reduced colonic ILFs. From this, we identified a novel mechanism regulating colonic ILF development through the action of interleukin (IL)-25 on IL-23 and its ability to modulate T regulatory cell (Treg) differentiation. Colonic ILF develop in the absence of a number of factors required for the development of their SI counterparts and can be specifically suppressed by factors other than IL-25. However, IL-23 is the only factor identified that specifically promotes colonic ILFs without affecting SI-ILF development. Both IL-23 and ILFs are associated with inflammatory bowel disease, suggesting that disruption to this pathway may have an important role in the breakdown of microbiota-immune homeostasis.

T-regulatory cells and programmed death 1+ T cells contribute to effector T-cell dysfunction in patients with chronic obstructive pulmonary disease

RATIONALE

Previous studies from our laboratory have shown that peripheral blood mononuclear cells (PBMCs) from patients with chronic obstructive pulmonary disease (COPD) prone to exacerbations with nontypeable Haemophilus influenzae have impaired responses to lipoprotein P6. We hypothesized that an underlying immunosuppressive network could be responsible for the defective antibacterial immunity observed in these patients. We evaluated T regulatory cells (Tregs), myeloid-derived suppressor cells (MDSC), and exhausted T effector cells (programmed death 1 [PD-1](+)) in patients with COPD, because these cells are known to play a pivotal role in suppressing immune responses.

OBJECTIVES

We performed an in-depth characterization of Tregs, T effector cells, and MDSC in COPD and correlated their levels and function with disease severity.

METHODS

Treg, effector T cell, and MDSC frequency from patients with COPD and healthy subjects' PBMCs were analyzed by flow cytometry. Treg immunosuppressive capacity was measured by in vitro suppression assay. The frequency of interferon-γ producing T cells and T-cell proliferation were measured after blocking CTLA-4 and PD-1. Plasma proinflammatory and immunosuppressive cytokine levels were measured.

MEASUREMENTS AND MAIN RESULTS

Significantly increased levels of Tregs, MDSC, and PD-1(+) exhausted effector T cells were present in patients with COPD compared with healthy subjects. Tregs from patients with COPD suppressed P6-specific T-cell proliferation to a greater extent than Tregs from healthy subjects. Plasma levels of Treg-generated cytokines, IL-10, and transforming growth factor-β were elevated. Blockade of CTLA-4 resulted in significant augmentation of T-cell IFN-γ production in patients with COPD.

CONCLUSIONS

Functionally suppressive Tregs, MDSCs, and exhausted PD-1(+) T cells contribute to effector T-cell dysfunction in COPD.

Reishi Protein LZ-8 Induces FOXP3(+) Treg Expansion via a CD45-Dependent Signaling Pathway and Alleviates Acute Intestinal Inflammation in Mice

LZ-8, an immunomodulatory protein isolated from Ganoderma lucidum (also known as Ling-Zhi or Reishi), has been shown to promote cell proliferation and IL-2 production in T cells. In this study, we show that LZ-8 induces the expansion of both murine and human CD4⁺ T cells into FOXP3⁺ regulatory T (Treg) cells. LZ-8 treatment was found to stimulate a 4-fold and a 10-fold expansion in the Treg populations of murine and human primary CD4⁺ T cells, respectively. In addition, the expression of CTLA-4 and IL-10 was induced in LZ-8-treated CD4⁺ T cells. Using neutralizing antibodies and gene-deficient T-cell lines, we also found that LZ-8 promotes Treg expansion through a CD45-mediated signaling pathway and that the CD18-dependent induction of IL-2 was involved in Treg formation and IL-10 production. The suppressive activity of LZ-8 was confirmed using a murine model of DSS-induced colitis; the disease was alleviated by the adoptive transfer of LZ-8-treated CD4⁺ T cells. In conclusion, a new regulatory function for LZ-8 was identified, and the molecular mechanisms underlying this function were elucidated.

Deletion of Foxp3+ regulatory T cells in genetically targeted mice supports development of intestinal inflammation

BACKGROUND

Mice lacking Foxp3+ regulatory T (Treg) cells develop severe tissue inflammation in lung, skin, and liver with premature death, whereas the intestine remains uninflamed. This study aims to demonstrate the importance of Foxp3+ Treg for the activation of T cells and the development of intestinal inflammation.

METHODS

Foxp3-GFP-DTR (human diphtheria toxin receptor) C57BL/6 mice allow elimination of Foxp3+ Treg by treatment with Dx (diphtheria toxin). The influence of Foxp3+ Treg on intestinal inflammation was tested using the CD4+ T-cell transfer colitis model in Rag-/- C57BL/6 mice and the acute DSS-colitis model.

RESULTS

Continuous depletion of Foxp3+ Treg in Foxp3-GFP-DTR mice led to dramatic weight loss and death of mice by day 28. After 10 days of depletion of Foxp3+ Treg, isolated CD4+ T-cells were activated and produced extensive amounts of IFN-γ, IL-13, and IL-17A. Transfer of total CD4+ T-cells isolated from Foxp3-GFP-DTR mice did not result in any changes of intestinal homeostasis in Rag-/- C57BL/6 mice. However, administration of DTx between days 14 and 18 after T-cell reconstitution, lead to elimination of Foxp3+ Treg and to immediate weight loss due to intestinal inflammation. This pro-inflammatory effect of Foxp3+ Treg depletion consecutively increased inflammatory cytokine production. Further, the depletion of Foxp3+ Treg from Foxp3-GFP-DTR mice increased the severity of acute dSS-colitis accompanied by 80% lethality of Treg-depleted mice. CD4+ effector T-cells from Foxp3+ Treg-depleted mice produced significantly more pro-inflammatory cytokines.

CONCLUSION

Intermittent depletion of Foxp3+ Treg aggravates intestinal inflammatory responses demonstrating the importance of Foxp3+ Treg for the balance at the mucosal surface of the intestine.

Abatacept for Crohn's disease and ulcerative colitis

BACKGROUND & AIMS

The efficacy of abatacept, a selective costimulation modulator, in Crohn's disease (CD) and ulcerative colitis (UC) is unknown.

METHODS

Four placebo-controlled trials evaluated the efficacy and safety of abatacept as induction (IP) and maintenance (MP) therapy in adults with active, moderate-to-severe CD (CD-IP; CD-MP) and UC (UC-IP1; UC-MP). In CD-IP and UC-IP1, 451 patients with CD and 490 patients with UC were randomized to abatacept 30, 10, or 3 mg/kg (according to body weight) or placebo, and dosed at weeks 0, 2, 4, and 8. In MP, 90 patients with CD and 131 patients with UC who responded to abatacept at week 12 in the induction trials were randomized to abatacept 10 mg/kg or placebo every 4 weeks through week 52.

RESULTS

In CD-IP, 17.2%, 10.2%, and 15.5% of patients receiving abatacept 30, 10, and 3 mg/kg achieved a clinical response at weeks 8 and 12, vs 14.4% receiving placebo (P = .611, P = .311, and P = .812, respectively). In UC-IP1, 21.4%, 19.0%, and 20.3% of patients receiving abatacept 30, 10, and 3 mg/kg achieved a clinical response at week 12, vs 29.5% receiving placebo (P = .124, P = .043, and P = .158, respectively). In CD-MP, 23.8% vs 11.1% of abatacept vs placebo patients were in remission at week 52. In UC-MP, 12.5% vs 14.1% of patients receiving abatacept vs placebo were in remission at week 52. Safety generally was comparable between groups.

CONCLUSIONS

The studies showed that abatacept is not efficacious for the treatment of moderate-to-severe CD or UC.

The CD4+CD28null and the regulatory CD4+CD25High T-cell phenotypes in patients with ulcerative colitis during active and quiescent disease, and following colectomy

The CD4+CD25High T-cell phenotype has an essential immunoregulatory role, while the CD4+CD28null T-cell reflects immune pathology. We investigated the profiles of the CD4+CD25High and the CD4+CD28null T-cell phenotypes in patients with ulcerative colitis (UC) during active and quiescent phases as well as following colectomy. Fifty-nine UC patients, 34 active (UCa) and 25 quiescent (UCq) together with 19 healthy controls (HC) were included. Ten of 34 UCa patients underwent colectomy due to unremitting UC (UCo). Immunohistochemical phenotypic of the peripheral blood lymphocytes bearing CD4, CD25 or CD28 was done for analyzes by a multiparameter fluorescence activated cell sorting technique. The expression of the CD4+CD25High phenotype was higher in UCq (P<0.01) or UCo (P<0.01) group vs UCa group. Further, the expression of the CD4+CD28null phenotype in UCa or UCo group was higher than in the HC group (P<0.05). However, the expression of the CD4+CD28null phenotype up to 12 months after colectomy was not significantly different from the levels in the same patients during acute phase. Our impression is that a high CD4+CD25High T-cell reflects alleviation of inflammation, while the expression of the CD4+CD28null T-cell phenotype is an etiologic feature in UC patients, and is maintained after removing the affected colon.

Infliximab therapy impacts the peripheral immune system of immunomodulator and corticosteroid naïve patients with Crohn's disease

BACKGROUND/AIMS

Infliximab (IFX), an antibody to tumor necrosis factor, (TNF)-α has efficacy in treating Crohn's disease (CD). However, knowledge of the potential effects of IFX on patients' immune profiles is lacking. The purpose of this study was to reveal the immunological effects of IFX.

METHODS

Twenty-two patients with a CD activity index (CDAI) of 194.2±92.9 and an average duration of disease of 3.26 months and 21 healthy controls were included. Patients were to have their first IFX remission induction therapy with 3 infusions (5 mg/kg) at weeks 0, 2, and 6. Oral 5-aminosalicylic acid was the only ongoing medication in the patient population. Blood samples at baseline, 12 hours after the first infusion and at week 14 were labeled with anti-CD4/CD25 antibodies for immunohistochemical measurement of regulatory T-cells (Treg). Serum cytokines and chemokines were measured by suspension array and ELISA.

RESULTS

CDAI significantly decreased prior to the second IFX infusion (p<0.001). Clinical remission rates were 77.3% and 91% by the second and third infusions, respectively. At baseline, interleukin (IL)-6 (p<0.03), IL-8 (p<0.03), IL-10 (p=0.050), IL-13 (p<0.01), transforming growth factor-β1 (p<0.01), and 'regulated on activation, normal T cell expressed and secreted' (RANTES) (p<0.01) were elevated in patients. After the initial IFX infusion, TNF-α (p<0.04), IL-6 (p<0.03), interferon (IFN)-γ (p<0.04), IFN-γ-inducible protein-10 (p<0.01), monocyte chemoattractant protein-1 (p<0.01), macrophage inflammatory protein-1β (p<0.01), and RANTES (p<0.01) were decreased. IFX infusion was associated with an increase in Treg (p<0.01) and a decrease in the Th1 (IFN-γ)/Th2 (IL-4) ratio (p<0.03).

CONCLUSIONS

IFX use was associated with restoration of the Th1/Th2 balance after a single infusion and seemed to promote induction of naïve Th0 lymphocytes to Treg. This knowledge should have clinical relevance.

Treatment of mice with dextran sulfate sodium-induced colitis with human interleukin 10 secreted by transformed Bifidobacterium longum

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) the etiology of which has not yet been fully clarified. Cytokine interleukin-10 (IL-10) plays a central role in downregulating inflammatory cascade in UC and is likely a candidate for therapeutic intervention. However, its intravenous administration is costly and inconvenient. Therefore, we established a novel IL-10 delivery system by transforming a hIL-10-containing plasmid into B. longum (BL-hIL-10) and investigated its effects on 5% dextran sulfate sodium (DSS)-induced ulcerative colitis in mice and the possible underlying mechanism. Our results show that (1) hIL-10 was expressed and secreted into the culture supernatant of BL-hIL-10 after L-arabinose induction in vitro as examined by Western blot, enzyme-linked immunosorbent assay (ELISA) and RT-PCR; (2) addition of BL-hIL-10 culture supernatant had no cytotoxic effect and morphological alteration, but significantly inhibited the enhancement of proinflammatory cytokines by lipopolysaccharide (LPS) in THP-1 cells; (3) oral administration of BL-hIL-10 alleviated colitis syndrome of the model mice, attenuated colitis-activated NF-κB pathway measured by DNA-binding assay and colitis-elevated expression of proinflammatory cytokines examined with CCK cytotoxic kits, and upregulated CD4+CD25+Foxp3+ Treg in blood and mesenteric lymph nodes measured by flow cytometry. In conclusion, BL-hIL-10 as a novel oral hIL-10 delivery system has been successfully established and oral administration of BL-hIL-10 alleviated inflammatory damage of colonic tissue in the model mice by blocking the colitis-activated NF-κB pathway and upregulating CD4+CD25+Foxp3+ Treg in blood and mesenteric lymph nodes in mice.

Mechanisms of impaired regulation by CD4(+)CD25(+)FOXP3(+) regulatory T cells in human autoimmune diseases

A lack of regulatory T (T(Reg)) cells that express CD4, CD25 and forkhead box P3 (FOXP3) results in severe autoimmunity in both mice and humans. Since the discovery of T(Reg) cells, there has been intense investigation aimed at determining how they protect an organism from autoimmunity and whether defects in their number or function contribute to the development of autoimmunity in model systems. The next phase of investigation - that is, to define the role that defects in T(Reg) cells have in human autoimmunity - is now underway. This Review summarizes our progress so far towards understanding the role of CD4(+)CD25(+)FOXP3(+) T(Reg) cells in human autoimmune diseases and the impact that this knowledge might have on the diagnosis and treatment of these diseases.

Increased airway T regulatory cells in asthmatic subjects

BACKGROUND

T regulatory cells (Tregs) may play a role in the suppression of effector lymphocyte activity in asthma. We hypothesized that Treg numbers would be increased in patients with more severe asthma. We also investigated the regulatory function of CD4 cells by expression of cytotoxic T-lymphocyte antigen 4 (CTLA4), and the number of these cells that are intraepithelial lymphocytes expressing CD103.

OBJECTIVES

The primary aim was to investigate Treg numbers in the BAL of patients with moderate to severe asthma compared with mild asthma and healthy controls. The secondary aim was to investigate BAL CD4(+)CTLA4 and CD4(+)CD103 expression in these groups.

METHODS

Airway lymphocytes obtained by bronchoscopy from healthy control subjects (six) and patients with mild (15) and moderate to severe (13) asthma were characterized by multiparameter flow cytometric analysis using three methods to determine the numbers of CD4(+) Treg cells: CD4(+)CD25(bright), CD4(+)CD25(+)CD127(-), and CD4(+)FoxP3(+).

RESULTS

The %CD4(+)FoxP3(+) Tregs were increased in the BAL of patients with moderate to severe asthma (median 4.8%) compared with both mild asthma patients (median 2.5%, P = .03) and healthy subjects (median 0.95, P = .003). Similar findings were observed for CD4(+)CD25(+)CD127(-) Treg numbers, but not CD4CD25(bright). CD4(+) CTLA4 and CD103 expressions were raised in moderate to severe asthma patients compared with those with mild asthma and healthy controls.

CONCLUSIONS

The number of cells displaying regulatory capacity, either through FoxP3 expression or CTLA4 expression, is increased in moderate to severe asthma. CD4(+)CD103(+) intraepithelial lymphocytes can be retained at tissue sites of inflammation; our findings indicate a role for these cells in asthma pathophysiology.

Foxp3+ regulatory T cells, Th17 effector cells, and cytokine environment in inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is thought to result from an aberrant immune response. Inflammation in IBD may be caused by the loss of homeostasis between CD4+ CD25high Foxp3+ regulatory cells (Treg) and proinflammatory Th17 cells. The aim of this study was to investigate Treg and Th17 cells in the peripheral blood and intestinal mucosa of IBD patients and to assess the mucosal cytokine environment.

METHODS

Treg and Th17 cells were measured in peripheral blood of 63 IBD patients and 28 controls by flow cytometry. Forkhead box p3 (Foxp3), interleukin (IL)-17a, IL-1beta, IL-6, IL-21, IL-23, and transforming growth factor (TGF)-beta mRNA were analyzed using real-time reverse transcription polymerase chain reaction in intestinal biopsies of 24 IBD and 18 control subjects.

RESULTS

A decrease in Treg and increase in Th17 cells was observed in the peripheral blood of IBD patients. When measured in the same patient and expressed as a ratio, a significant decrease in Treg/Th17 ratio was observed in IBD. Elevated expression of Foxp3, IL-17a, IL-1beta, and IL-6 was observed in the mucosa of IBD patients, while TGF-beta was only elevated in ulcerative colitis.

CONCLUSION

IBD is associated with a reduced ratio of Treg to Th17 cells in peripheral blood and is characterized by a proinflammatory cytokine microenvironment, which supports the continued generation of Th17 cells.

Foxp3+ regulatory T cells, Th17 effector cells, and cytokine environment in inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is thought to result from an aberrant immune response. Inflammation in IBD may be caused by the loss of homeostasis between CD4+ CD25high Foxp3+ regulatory cells (Treg) and proinflammatory Th17 cells. The aim of this study was to investigate Treg and Th17 cells in the peripheral blood and intestinal mucosa of IBD patients and to assess the mucosal cytokine environment.

METHODS

Treg and Th17 cells were measured in peripheral blood of 63 IBD patients and 28 controls by flow cytometry. Forkhead box p3 (Foxp3), interleukin (IL)-17a, IL-1beta, IL-6, IL-21, IL-23, and transforming growth factor (TGF)-beta mRNA were analyzed using real-time reverse transcription polymerase chain reaction in intestinal biopsies of 24 IBD and 18 control subjects.

RESULTS

A decrease in Treg and increase in Th17 cells was observed in the peripheral blood of IBD patients. When measured in the same patient and expressed as a ratio, a significant decrease in Treg/Th17 ratio was observed in IBD. Elevated expression of Foxp3, IL-17a, IL-1beta, and IL-6 was observed in the mucosa of IBD patients, while TGF-beta was only elevated in ulcerative colitis.

CONCLUSION

IBD is associated with a reduced ratio of Treg to Th17 cells in peripheral blood and is characterized by a proinflammatory cytokine microenvironment, which supports the continued generation of Th17 cells.

The relationship between the expression of the glucocorticoid receptor in biopsied colonic mucosa and the glucocorticoid responsiveness of ulcerative colitis patients

The objective of this study was to clarify the relationship between the frequency of infiltrating cells expressing the glucocorticoid receptors (GR) alpha and beta in biopsied colonic mucosa and the glucocorticoid (GC) responsiveness of ulcerative colitis (UC) patients. Active UC patients (n=38) were divided into GC-sensitive and GC-resistant groups. GRbeta(+) cells were significantly higher in the GC-resistant group than in the GC-sensitive and control groups. GRalpha mRNA was expressed in all UC patients, while GRbeta mRNA was expressed in only 1 patient in the GC-sensitive group (n=6) and 7 patients in the GC-resistant group (n=8). Double-positive cells for GRbeta and CD4 or CD19 were frequently observed. The Foxp3(+) cell count was significantly higher in the GC-sensitive group than in the GC-resistant group, but double Foxp3(+)GRbeta(+) cells were not observed. These results indicated that the sensitivity of GC therapy could probably be predicted by immunostaining biopsy specimens for GRbeta and Foxp3.

Increased FOXP3 expression in small-bowel mucosa of children with coeliac disease and type I diabetes mellitus

OBJECTIVE

To determine whether the expression of FOXP3 is changed in small-bowel mucosa in coeliac disease (CD).

MATERIAL AND METHODS

The study comprised 52 patients (mean age 8.01+/-6.14 years) who had undergone small-bowel biopsies. CD only was diagnosed in 16 patients, and CD with type I diabetes mellitus (T1D) in 7. These 23 patients and 4 others without CD had partial or subtotal villous atrophy (PVA, SVA). Twenty-five persons without CD had normal mucosa. The transcription level of the FOXP3 gene (Hs00203958_m1) was evaluated in biopsy samples (small bowel) using TaqMan gene expression assays. FOXP3 protein in mucosal cells was evaluated with mouse anti-human FOXP3 antibodies and CD25(+), and CD4(+) T cells were evaluated by mouse monoclonal antibodies.

RESULTS

Expression of FOXP3 mRNA was higher in both PVA and SVA compared to normal mucosa (p=0.007). Patients with CD and T1D had higher expression of FOXP3 mRNA than patients with CD alone (p=0.02). The number of FOXP3(+) cells in intestinal mucosa was higher in patients with CD, especially those with coexisting T1D, than in those with normal mucosa (p=0.01). The results of double staining showed that, among all positive cells, FOXP3 expression alone was revealed in 25.6% of the cells, CD25 positivity in 18% and both markers simultaneously were found in 56.5% of lymphocytes (p=0.03). Double staining for CD4 and FOXP3 showed that 87.5% of cells were CD4(+), 2.8% were FOXP3(+) and 9.7% of cells simultaneously expressed the CD4 and FOXP3 markers.

CONCLUSIONS

A more pronounced expression of FOXP3 mRNA and also the number of FOXP3(+) cells (with simultaneous expression of CD25 and CD4 markers) were found in the small-bowel biopsy specimens obtained from children with CD, particularly those with coexisting T1D, compared with the FOXP3 expression in normal mucosa.

Role of regulatory T-cells in autoimmunity

There has been considerable historical interest in the concept of a specialist T-cell subset which suppresses over-zealous or inappropriate T-cell responses. However, it was not until the discovery that CD4(+)CD25(+) T-cells had suppressive capabilities both in vitro and in vivo that this concept regained credibility and developed into one of the most active research areas in immunology today. The notion that in healthy individuals there is a subset of T(reg)-cells (regulatory T-cells) involved in 'policing' the immune system has led to the intensive exploration of the role of this subset in disease resulting in a number of studies concluding that a quantitative or qualitative decline in T(reg)-cells is an important part of the breakdown in self-tolerance leading to the development of autoimmune diseases. Although T(reg)-cells have subsequently been widely postulated to represent a potential immunotherapy option for patients with autoimmune disease, several studies of autoimmune disorders have demonstrated high numbers of T(reg)-cells in inflamed tissue. The present review highlights the need to consider a range of other factors which may be impairing T(reg)-cell function when considering the mechanisms involved in the breakdown of self-tolerance rather than focussing on intrinsic T(reg)-cell factors.

Paucicellular lymphocytic colitis: is it a minor form of lymphocytic colitis? A clinical pathological and immunological study

OBJECTIVES

It has been suggested that paucicellular lymphocytic colitis (PLC) should be considered to be part of the morphological spectrum of microscopic colitis. The aim of the study was to evaluate whether PLC may be considered to be a true microscopic colitis, and in this case, whether it is a minor form of lymphocytic colitis (LC) or a different entity.

METHODS

All incident cases of PLC, LC, and collagenous colitis (CC) during the period 2004-2006 were included. The incidence rate and the clinical, histopathological, and immunological features of PLC were assessed and compared with those of both LC and CC. Immunoreactivities to CD25, c-Kit, and FOXP3 in lamina propria were assessed.

RESULTS

In all, 19 patients with CC, 19 with LC, and 26 with PLC were identified. CD25+FOXP3+ expression was seen only in classical forms of microscopic colitis: 12 of 19 LC, 14 of 20 CC, and none of 20 PLC cases (P < 0.0001). Diarrhea ceased in 21 of the 26 patients, with a decrease in the daily stool number from 5.08 +/- 0.44 to 1.7 +/- 0.2 (P < 0.005). The five patients with no response to therapy fulfilled the Rome II criteria of irritable bowel syndrome (IBS).

CONCLUSIONS

The incidence rate of PLC, identified using objective histological criteria, was higher than those of CC and LC. The lack of expression of CD25+FOXP3+ cells in PLC, in contrast to those seen in both LC and CC, would suggest the existence of different pathophysiological mechanisms and does not support that PLC is a minor form of LC.

The expression profile of functional regulatory T cells, CD4+CD25high+/forkhead box protein P3+, in patients with ulcerative colitis during active and quiescent disease

Regulatory T cells (T(reg)) have an essential role in maintaining immune tolerance in the gut. The functional CD4(+) T(reg) express the transcription factor forkhead box protein 3 (FoxP3) or a CD25(high) in humans. Further, depletion of elevated granulocytes/monocytes by extracorporeal adsorption (GMA) induces immunomodulation in patients with ulcerative colitis (UC). We investigated the impact of GMA on T(reg). Thirty-one UC patients, clinical activity index (CAI) 12.1 +/- 2.97, refractory to conventional medications including intravenous corticosteroid and 13 healthy controls (HC), were included. Patients received five GMA sessions over 5 weeks. Biopsies from the rectal mucosa and blood samples at baseline and post-GMA were immunostained with anti-CD4/FoxP3 and anti-CD4/CD25 antibodies for immunohistochemistry and flow cytometry. Following GMA, 22 of 31 patients achieved remission (CAI <or= 4, P < 0.01) and their endoscopic activity index decreased from 10.6 +/- 2.32 to 4.75 +/- 1.48 (P = 0.003). The circulating CD4(+)CD25(high+) T(reg) level was low and increased markedly in responders (P < 0.02). In the nine non-responders, the baseline CD4(+)CD25(high+) T(reg) level was about 50% of the level in the responders (P < 0.03) or in the HC (P < 0.01), and all nine had to undergo colectomy. Conversely, the number of CD4(+)/FoxP3(+) mucosal T(reg) in GMA responders decreased significantly after the fifth GMA session compared with the baseline level (P < 0.05). It is believed that the CD4(+) T(reg) has an essential role in the control of immune pathology in UC patients and a net influx of these cells from the circulation into the mucosa may proceed to suppress inflammation. GMA can impact the circulating as well as the mucosal levels of T(reg).

Probiotics and immunity

Probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host, including the gastrointestinal tract. While this beneficial effect was originally thought to stem from improvements in the intestinal microbial balance, there is now substantial evidence that probiotics can also provide benefits by modulating immune functions. In animal models, probiotic supplementation is able to provide protection from spontaneous and chemically induced colitis by downregulating inflammatory cytokines or inducing regulatory mechanisms in a strain-specific manner. In animal models of allergen sensitization and murine models of asthma and allergic rhinitis, orally administered probiotics can strain-dependently decrease allergen-specific IgE production, in part by modulating systemic cytokine production. Certain probiotics have been shown to decrease airway hyperresponsiveness and inflammation by inducing regulatory mechanisms. Promising results have been obtained with probiotics in the treatment of human inflammatory diseases of the intestine and in the prevention and treatment of atopic eczema in neonates and infants. However, the findings are too variable to allow firm conclusions as to the effectiveness of specific probiotics in these conditions.