Macrophage Epithelial Reprogramming Underlies Mycobacterial Granuloma Formation and Promotes Infection.

Mycobacterium tuberculosis infection in humans triggers formation of granulomas, which are tightly organized immune cell aggregates that are the central structure of tuberculosis. Infected and uninfected macrophages interdigitate, assuming an altered, flattened appearance. Although pathologists have described these changes for over a century, the molecular and cellular programs underlying this transition are unclear. Here, using the zebrafish-Mycobacterium marinum model, we found that mycobacterial granuloma formation is accompanied by macrophage induction of canonical epithelial molecules and structures. We identified fundamental macrophage reprogramming events that parallel E-cadherin-dependent mesenchymal-epithelial transitions. Macrophage-specific disruption of E-cadherin function resulted in disordered granuloma formation, enhanced immune cell access, decreased bacterial burden, and increased host survival, suggesting that the granuloma can also serve a bacteria-protective role. Granuloma macrophages in humans with tuberculosis were similarly transformed. Thus, during mycobacterial infection, granuloma macrophages are broadly reprogrammed by epithelial modules, and this reprogramming alters the trajectory of infection and the associated immune response.

Molecular mechanism for strengthening E-cadherin adhesion using a monoclonal antibody.

E-cadherin (Ecad) is an essential cell-cell adhesion protein with tumor suppression properties. The adhesive state of Ecad can be modified by the monoclonal antibody 19A11, which has potential applications in reducing cancer metastasis. Using X-ray crystallography, we determine the structure of 19A11 Fab bound to Ecad and show that the antibody binds to the first extracellular domain of Ecad near its primary adhesive motif: the strand-swap dimer interface. Molecular dynamics simulations and single-molecule atomic force microscopy demonstrate that 19A11 interacts with Ecad in two distinct modes: one that strengthens the strand-swap dimer and one that does not alter adhesion. We show that adhesion is strengthened by the formation of a salt bridge between 19A11 and Ecad, which in turn stabilizes the swapped ß-strand and its complementary binding pocket. Our results identify mechanistic principles for engineering antibodies to enhance Ecad adhesion.

Lipopolysaccharide Induces Alveolar Macrophage Necrosis via CD14 and the P2X7 Receptor Leading to Interleukin-1α Release.

Acute lung injury (ALI) remains a serious health issue with little improvement in our understanding of the pathophysiology and therapeutic approaches. We investigated the mechanism that lipopolysaccharide (LPS) induces early neutrophil recruitment to lungs and increases pulmonary vascular permeability during ALI. Intratracheal LPS induced release of pro-interleukin-1α (IL-1α) from necrotic alveolar macrophages (AM), which activated endothelial cells (EC) to induce vascular leakage via loss of vascular endothelial (VE)-cadherin. LPS triggered the AM purinergic receptor P2X7(R) to induce Ca(2+) influx and ATP depletion, which led to necrosis. P2X7R deficiency significantly reduced necrotic death of AM and release of pro-IL-1α into the lung. CD14 was required for LPS binding to P2X7R, as CD14 neutralization significantly diminished LPS induced necrotic death of AM and pro-IL-1α release. These results demonstrate a key role for pro-IL-1α from necrotic alveolar macrophages in LPS-mediated ALI, as a critical initiator of increased vascular permeability and early neutrophil infiltration.

E-Cadherin restricts mast cell degranulation in mice.

Crosslinking of FcεRI-bound IgE triggers the release of a large number of biologically active, potentially anaphylactic compounds by mast cells. FcεRI activation ought to be well-controlled to restrict adverse activation. As mast cells are embedded in tissues, adhesion molecules may contribute to limiting premature activation. Here, we report that E-Cadherin serves that purpose. Having confirmed that cultured mast cells express E-Cadherin, a mast-cell-specific E-Cadherin deficiency, Mcpt5-Cre E-Cdhfl/fl mice, was used to analyze mast cell degranulation in vitro and in vivo. Cultured peritoneal mast cells from Mcpt5-Cre E-Cdhfl/fl mice were normal with respect to many parameters but showed much-enhanced degranulation in three independent assays. Soluble E-Cadherin reduced the degranulation of control cells. The release of some newly synthesized inflammatory cytokines was decreased by E-Cadherin deficiency. Compared to controls, Mcpt5-Cre E-Cdhfl/fl mice reacted much stronger to IgE-dependent stimuli, developing anaphylactic shock. We suggest E-Cadherin-mediated tissue interactions restrict mast cell degranulation to prevent their precocious activation.

Massive digital gene expression analysis reveals different predictive profiles for immune checkpoint inhibitor therapy between adenocarcinoma and squamous cell carcinoma of advanced lung cancer.

BACKGROUND: Immune checkpoint inhibitors prolong the survival of non-small cell lung cancer (NSCLC) patients. Although it has been acknowledged that there is some correlation between the efficacy of anti-programmed cell death-1 (PD-1) antibody therapy and immunohistochemical analysis, this technique is not yet considered foolproof for predicting a favorable outcome of PD-1 antibody therapy. We aimed to predict the efficacy of nivolumab based on a comprehensive analysis of RNA expression at the gene level in advanced NSCLC. METHODS: This was a retrospective study on patients with NSCLC who were administered nivolumab at the Kansai Medical University Hospital. To identify genes associated with response to anti-PD-1 antibodies, we grouped patients into responders (complete and partial response) and non-responders (stable and progressive disease) to nivolumab therapy. Significant genes were then identified for these groups using Welch's t-test. RESULTS: Among 42 analyzed cases (20 adenocarcinomas and 22 squamous cell carcinomas), enhanced expression of MAGE-A4, BBC3, and OTOA genes was observed in responders with adenocarcinoma, and enhanced expression of DAB2, HLA-DPB,1 and CDH2 genes was observed in responders with squamous cell carcinoma. CONCLUSIONS: This study predicted the efficacy of nivolumab based on a comprehensive analysis of mRNA expression at the gene level in advanced NSCLC. We also revealed different gene expression patterns as predictors of the effectiveness of anti PD-1 antibody therapy in adenocarcinoma and squamous cell carcinoma.

Neonatal Injury Increases Gut Permeability by Epigenetically Suppressing E-Cadherin in Adulthood.

Altered intestinal epithelial integrity is an important susceptibility trait in inflammatory bowel disease (IBD), and early life stressors are reported to contribute to this disease susceptibility in adulthood. To identify disease mechanisms associated with early-life trauma that exacerbate IBD in adulthood, we used a "double-hit" neonatal inflammation (NI) and adult inflammation (AI) model that exhibits more severe mucosal injury in the colon later in life. In this study, we explore the underlying mechanisms of this aggravated injury. In rats exposed to both NI and AI, we found sustained increases in colonic permeability accompanied by significantly attenuated expression of the epithelial junction protein E-cadherin. Quantitative RT-PCR revealed a decreased Cdh1 (gene of E-cadherin) mRNA expression in NI + AI rats compared with NI or AI rats. Next, we performed microRNA microarrays to identify potential regulators of E-cadherin in NI + AI rats. We confirmed the overexpression of miR-155, a predicted regulator of E-cadherin, and selected it for further analysis based on reported significance in human IBD. Using ingenuity pathway analysis software, the targets and related canonical pathway of miR-155 were analyzed. Mechanistic studies identified histone hyperacetylation at the Mir155 promoter in NI + AI rats, concomitant with elevated RNA polymerase II binding. In vitro, E-cadherin knockdown markedly increased epithelial cell permeability, as did overexpression of miR-155 mimics, which significantly suppressed E-cadherin protein. In vivo, NI + AI colonic permeability was significantly reversed with administration of miR-155 inhibitor rectally. Our collective findings indicate that early-life inflammatory stressors trigger a significant and sustained epithelial injury by suppressing E-cadherin through epigenetic mechanisms.

New 'Antigens' in Membranous Nephropathy.

Membranous nephropathy (MN) occurs due to deposition of immune complexes along the subepithelial region of glomerular basement membrane. Two previously identified target antigens for the immune complexes, PLA2R (identified in 2009) and THSD7A (in 2014), account for approximately 60% of all MN, both primary and secondary. In the remaining MN, target antigens were unknown. Use of laser microdissection and mass spectrometry enabled identification of new "antigens." This approach led to the identification of four novel types of MN: exotosin 1 (EXT1)- and exotosin 2 (EXT2)-associated MN, NELL1-associated MN, Sema3B-associated MN, and PCDH7-associated MN. Each of these represents a distinct disease entity, with different clinical and pathologic findings. In this review, the structure of the proteins and the clinical and pathologic findings of the new types of MN are discussed. The role of mass spectrometry for accurate diagnosis of MN cannot be overemphasized. Finally, any classification of MN should be made on the basis of the antigens that are detected. Further studies are required to understand the pathophysiology, response to treatment, and outcomes of these new MNs.

Identification of a primary antigenic target of epitope spreading in endemic pemphigus foliaceus.

Epitope spreading is an important mechanism for the development of autoantibodies (autoAbs) in autoimmune diseases. The study of epitope spreading in human autoimmune diseases is limited due to the major challenge of identifying the initial/primary target epitopes on autoantigens in autoimmune diseases. We have been studying the development of autoAbs in an endemic human autoimmune disease, Brazilian pemphigus foliaceus (or Fogo Selvagem (FS)). Our previous findings demonstrated that patients before (i.e. preclinical) and at the onset of FS have antibody (Ab) responses against other keratinocyte adhesion molecules in addition to the main target autoantigen of FS, desmoglein 1 (Dsg1), and anti-Dsg1 monoclonal Abs (mAbs) cross-reacted with an environmental antigen LJM11, a sand fly saliva protein. Since sand fly is prevalent in FS endemic regions, individuals in these regions could develop Abs against LJM11. The anti-LJM11 Abs could recognize different epitopes on LJM11, including an epitope that shares the structure similarity with an epitope on Dsg1 autoantigen. Thus, Ab response against this epitope on LJM11 could be the initial autoAb response detected in individuals in FS endemic regions, including those who eventually developed FS. Accordingly, this LJM11 and Dsg1 cross-reactive epitope on Dsg1 could be the primary target of the autoimmune response in FS. This investigation aimed to determine whether the autoAb responses against keratinocyte adhesion molecules are linked and originate from the immune response to LJM11. The anti-Dsg1 mAbs from preclinical FS and FS individuals were employed to determine their specificity or cross-reactivity to LJM11 and keratinocyte adhesion molecules. The cross-reactive epitopes on autoantigens were mapped. Our results indicate that all tested mAbs cross-reacted with LJM11 and keratinocyte adhesion molecules, and we identified an epitope on these keratinocyte adhesion molecules which is mimicked by LJM11. Thus, the cross-reactivity could be the mechanism by which the immune response against an environmental antigen triggers the initial autoAb responses. Epitope spreading leads to the pathogenic autoAb development and ensuing FS among genetically susceptible individuals.

RGD cadherins and α2ß1 integrin in cancer metastasis: A dangerous liaison.

We propose a new cadherin family classification comprising epithelial cadherins (cadherin 17 [CDH17], cadherin 16, VE-cadherin, cadherin 6 and cadherin 20) containing RGD motifs within their sequences. Expression of some RGD cadherins is associated with aggressive forms of cancer during the late stages of metastasis, and CDH17 and VE-cadherin have emerged as critical actors in cancer metastasis. After binding to α2ß1 integrin, these cadherins promote integrin ß1 activation, and thereby cell adhesion, invasion and proliferation, in liver and lung metastasis. Activation of α2ß1 integrin provokes an affinity increase for type IV collagen, a major component of the basement membrane and a critical partner for cell anchoring in liver and other metastatic organs. Activation of α2ß1 integrin by RGD motifs breaks an old paradigm of integrin classification and supports an important role of this integrin in cancer metastasis. Recently, synthetic peptides containing the RGD motif of CDH17 elicited highly specific and selective antibodies that block the ability of CDH17 RGD to activate α2ß1 integrin. These monoclonal antibodies inhibit metastatic colonization in orthotopic mouse models of liver and lung metastasis for colorectal cancer and melanoma, respectively. Hopefully, blocking the cadherin RGD ligand capacity will give us control over the integrin activity in solid tumors metastasis, paving the way for development of new agents of cancer treatment.

Evaluation of E-Cadherin and ß-Catenin Immunoreactivity for Determining Undifferentiated Cells in Anaplastic Thyroid Carcinoma.

INTRODUCTION: An immunohistochemical study has occasionally been performed to diagnose anaplastic thyroid carcinoma (ATC). However, antibodies to confirm the undifferentiated nature of ATC have not yet been evaluated. The aim of this study was to evaluate E-cadherin and ß-catenin expressions in immunoreactivity to determine undifferentiated carcinoma cells in the diagnosis of ATC. METHODS: We immunohistochemically examined 29 ATCs, 30 poorly differentiated thyroid carcinomas (PDTCs), 22 well-differentiated thyroid carcinomas (WDTCs), and 3 squamous cell carcinomas. Antibodies for thyroid transcription factor-1 (TTF-1), paired-box gene 8 (PAX8), ß-catenin, and E-cadherin were used. RESULTS: All WDTCs tested positive for TTF-1, PAX8, and E-cadherin. The positive rates of TTF-1, PAX8, and E-cadherin were 93.3, 93.3, and 100%, respectively, in PDTCs and 17.2, 51.7, and 10.3%, respectively, in ATCs. WDTC expressed the lateral cell membrane staining for ß-catenin and E-cadherin, whereas PDTC showed circumferential cell membranous expression (fishnet pattern). ß-catenin cell membrane expression in ATCs is lost or discontinuous. Carcinoma cells with ß-catenin nuclear expression without cell membranous expression were scattered in 72.4% of ATCs but were not observed in the other carcinomas. CONCLUSION: We propose 3 immunohistochemical findings to determine undifferentiated carcinoma cells in the diagnosis of ATC: (1) ß-catenin nuclear expression with no or reduced cell membranous expression, (2) the loss or discontinuous pattern of E-cadherin expression, and (3) the loss of PAX8 nuclear expression.

MIF signaling blocking alleviates airway inflammation and airway epithelial barrier disruption in a HDM-induced asthma model.

Recent studies have indicated that Macrophage migration inhibitory factor (MIF) plays an important role in the prevention and treatment of asthma. However the role of MIF in airway inflammation and airway epithelial barrier disruption in house dust mite (HDM)-induced asthma has not been addressed. We hypothesized that MIF contributed to HDM-induced the production of Th2-associated cytokines and E-cadherin dysfunction in asthmatic mice and 16HBE cells. In vivo, a HDM-induced asthma mouse model was set up and mice treated with MIF antagonist ISO-1 after HDM. The mice treated with the ISO-1 ameliorated airway hyper-reactivity, airway inflammation, increased serum IgE levels, the aberrant arrangement of E-cadherin as well as the release of Th2 cytokines induced by HDM. In vitro, the exposure of 16HBE cells to HDM and rhMIF resulted in airway epithelial barrier disruption, inflammatory cytokine production and enhanced glycolytic flux. While these changes were attenuated by MIF siRNA treatment. Sequentially, treatment of 16HBE cells with PFKFB3 antagonist PFK15 significantly lowered rhMIF-induced these changes in 16HBE cells. Therefore, these results indicate that MIF may be an important contributor in airway inflammation and airway epithelial barrier disruption of HDM-induced asthma. Moreover, HDM specifically induces airway inflammation and airway epithelial barrier disruption of 16HBE cells through MIF-mediated enhancement of aerobic glycolysis.

ALPK1 Expression Is Associated with Lymph Node Metastasis and Tumor Growth in Oral Squamous Cell Carcinoma Patients.

Oral squamous cell carcinoma (OSCC) is the most common malignant cancer, with high mortality rates in advanced stages. Recent studies have shown that the expression of ALPK1 mRNA and its inhibitory differentiation function are associated with cancer progression. However, the expression and clinicopathologic features of ALPK1 in OSCC remain unexplored. Herein, the authors investigated the expression patterns of ALPK1 in 39 matched OSCC patients and examined the relationship between ALPK1 protein expression and clinicopathologic factors using immunohistochemical scores. Using Western blot analysis, ALPK1 expression was found to be significantly higher in tumor tissues than that in nontumor tissues. Through an immunoreactive scoring system, a significantly higher number of advanced-stage tumor size T4 and lymph node metastasis N2 exhibited higher ALPK1 expression levels than that exhibited by T1/T2/T3 tumors and N0/N1. In addition, ALPK1 protein expression was aberrant in malignant oral cancer cell lines compared with that in pre-malignant oral epithelial cells, whereas minimal expression was observed in normal oral epithelial cells. Knockdown of ALPK1 resulted in a significant reduction in cell growth, migration, and invasion capacity in vitro. Consequently, expression of N-cadherin and vimentin decreased in ALPK1-deficient cells. Thus, these results suggest that ALPK1 serves as a potential biomarker and target for OSCC development in late stages.

Prolyl Hydroxylase Domain-2 Protein Regulates Lipopolysaccharide-Induced Vascular Inflammation.

Acute lung injury and its more severe form, acute respiratory distress syndrome, are life-threatening respiratory disorders. Overwhelming pulmonary inflammation and endothelium disruption are commonly observed. Endothelial cells (ECs) are well recognized as key regulators in leukocyte adhesion and migration in response to bacterial infection. Prolyl hydroxylase domain (PHD)-2 protein, a major PHD in ECs, plays a critical role in intracellular oxygen homeostasis, angiogenesis, and pulmonary hypertension. However, its role in endothelial inflammatory response is unclear. We investigated the role of PHD2 in ECs during endotoxin-induced lung inflammatory responses with EC-specific PHD2 inducible knockout mice. On lipopolysaccharide challenge, PHD2 depletion in ECs attenuates lipopolysaccharide-induced increases of lung vascular permeability, edema, and inflammatory cell infiltration. Moreover, EC-specific PHD2 inducible knockout mice exhibit improved adherens junction integrity and endothelial barrier function. Mechanistically, PHD2 knockdown induces vascular endothelial cadherin in mouse lung microvascular primary endothelial cells. Moreover, PHD2 knockdown can increase hypoxia-inducible factor/vascular endothelial protein tyrosine phosphatase signaling and reactive oxygen species-dependent p38 activation, leading to the induction of vascular endothelial cadherin. Data indicate that PHD2 depletion prevents the formation of leaky vessels and edema by regulating endothelial barrier function. It provides direct in vivo evidence to suggest that PHD2 plays a pivotal role in vascular inflammation. The inhibition of endothelial PHD2 activity may be a new therapeutic strategy for acute inflammatory diseases.

Cellular responses to human cytomegalovirus infection: Induction of a mesenchymal-to-epithelial transition (MET) phenotype.

Human cytomegalovirus (HCMV) is the prototypical human ß-herpes virus. Here we perform a systems analysis of the HCMV host-cell transcriptome, using gene set enrichment analysis (GSEA) as an engine to globally map the host-pathogen interaction across two cell types. Our analysis identified several previously unknown signatures of infection, such as induction of potassium channels and amino acid transporters, derepression of genes marked with histone H3 lysine 27 trimethylation (H3K27me3), and inhibition of genes related to epithelial-to-mesenchymal transition (EMT). The repression of EMT genes was dependent on early viral gene expression and correlated with induction E-cadherin (CDH1) and mesenchymal-to-epithelial transition (MET) genes. Infection of transformed breast carcinoma and glioma stem cells similarly inhibited EMT and induced MET, arguing that HCMV induces an epithelium-like cellular environment during infection.

Chemical Antibody Mimics Inhibit Cadherin-Mediated Cell-Cell Adhesion: A Promising Strategy for Cancer Therapy.

One of the most promising strategies to treat cancer is the use of therapeutic antibodies that disrupt cell-cell adhesion mediated by dysregulated cadherins. The principal site where cell-cell adhesion occurs encompasses Trp2 found at the N-terminal region of the protein. Herein, we employed the naturally exposed highly conserved peptide Asp1-Trp2-Val3-Ile4-Pro5-Pro6-Ile7, as epitope to prepare molecularly imprinted polymer nanoparticles (MIP-NPs) to recognize cadherins. Since MIP-NPs target the site responsible for adhesion, they were more potent than commercially available therapeutic antibodies for inhibiting cell-cell adhesion in cell aggregation assays, and for completely disrupting three-dimensional tumor spheroids as well as inhibiting invasion of HeLa cells. These biocompatible supramolecular anti-adhesives may potentially be used as immunotherapeutic or sensitizing agents to enhance antitumor effects of chemotherapy.

Phenotypic Profiling of Circulating Tumor Cells in Metastatic Prostate Cancer Patients Using Nanoparticle-Mediated Ranking.

The analysis of circulating tumor cells (CTCs) provides a means to collect information about the evolving properties of a tumor during cancer progression and treatment. For patients with metastatic prostate cancer, noninvasive serial measurements of bloodborne cells may provide a means to tailor therapeutic decisions based on an individual patient's response. Here, we used a high-sensitivity profiling approach to monitor CTCs in patients with metastatic castrate-resistant prostate cancer (mCRPC) undergoing treatment with abiraterone and enzalutamide, two drugs used to treat advanced prostate cancer. The capture and profiling approach uses antibody-functionalized magnetic nanoparticles to sort cells according to protein expression levels. CTCs are tagged with magnetic nanoparticles conjugated to an antibody specific for the epithelial cell adhesion molecule (EpCAM) and sorted into four zones of a microfluidic device based on EpCAM expression levels. Our approach was compared to the FDA-cleared CellSearch method, and we demonstrate significantly higher capture efficiency of low-EpCAM cells compared to the commercial method. The nanoparticle-based approach detected CTCs from 86% of patients at baseline, compared to CellSearch which only detected CTCs from 60% of patients. Patients were stratified as prostate specific antigen (PSA) progressive versus responsive based on clinically acceptable definitions, and it was observed that patients with a limited response to therapy had elevated levels of androgen receptor variant 7 (ARV7) and the mesenchymal marker, N-cadherin, expressed on their CTCs. In addition, these CTCs exhibited lower EpCAM expression. The results highlight features of CTCs associated with disease progression on abiraterone or enzalutamide, including mesenchymal phenotypes and increased expression levels of ARV7. The use of a high-sensitivity method to capture and profile CTCs provides more informative data concerning the phenotypic properties of these cells as patients undergo treatment relative to an FDA-cleared method.

IFNγ inhibits fibroblast-leading tumor cell invasion through downregulating N-cadherin.

Tumor metastasis accounts for most tumor-associated mortality and is closely related with stromal fibroblasts in the tumor microenvironment. It was reported that fibroblasts promoted tumor metastasis through directly leading tumor cell invasion; however, inflammatory microenvironment in the growing tumor may influence the outcome. Here, we found that the cytokine IFNγ, a key immune mediator secreted by T cells, could alter mouse lung tumor associated fibroblast-leading LLC tumor cell invasion in Matrigel. The motility of fibroblasts and adhesion with tumor cells were dramatically impaired upon IFNγ stimulation. We further found that IFNγ reduced the expression of N-cadherin on the surface of fibroblasts through upregulating SMAD7 and suppressing the downstream SMAD2 phosphorylation. N-cadherin was essential for fibroblast motility and adhesions with tumor cells. Moreover, fibroblasts could promote tumor progression and the deficiency of IFNγR signaling in fibroblasts reduced liver metastasis of LLC tumor in vivo. Collectively, our results demonstrate that IFNγ inhibits fibroblast-leading tumor cell invasion by inhibiting the motility of fibroblasts and their adhesion with tumor cells. The findings indicate that inflammatory cytokines in the tumor microenvironment may regulate the fibroblast-associated tumor metastasis.

Interleukin-17 and -22 synergy linking inflammation and EMT-dependent fibrosis in Sjögren's syndrome.

Primary Sjögren's syndrome (pSS) is a chronic inflammatory, autoimmune and systemic disorder commonly associated with dry eyes and a dry mouth. Recently, the hypothetical link between epithelial-mesenchymal transition (EMT)-dependent salivary gland (SG) fibrosis and chronic inflammatory conditions has been suggested. In this study, we present data demonstrating a negative correlation of the epithelial marker E-cadherin expression and a positive correlation of mesenchymal vimentin and collagen type I expression with increasing degrees of tissue inflammation in pSS SG specimens. In addition, as it is not clear whether dysregulated cytokines in pSS, interleukin (IL)-17 and IL-22 may also contribute to the EMT-dependent fibrosis process, the effect of IL-17 and IL-22 treatment on EMT-dependent SG fibrosis was evaluated in primary human salivary gland epithelial cells (SGEC) isolated from healthy subjects. Here we present data demonstrating that IL-17 and IL-22 can induce SGEC to undergo a morphological and phenotypical transition to a mesenchymal phenotype. In support of this, vimentin and collagen type I were up-regulated while a decreased expression of E-cadherin occurs after interleukin treatment, and co-operation between IL-17 and Il-22 was required to induce the EMT.

E-cadherin marks a subset of inflammatory dendritic cells that promote T cell-mediated colitis.

Dendritic cells (DCs) play a pivotal role in controlling the balance between tolerance and immunity in the intestine. Gut conditioned CD103(+) DCs promote regulatory T (Treg) cell responses; however, little is known about DCs that drive inflammation in the intestine. Here, we show that monocyte-derived inflammatory DCs that express E-cadherin, the receptor for CD103, promote intestinal inflammation. E-cadherin(+) DCs accumulated in the inflamed mesenteric lymph nodes and colon, had high expression of toll-like receptors, and produced colitogenic cytokines, such as IL-6 and IL-23, after activation. Importantly, adoptive transfer of E-cadherin(+) DCs into T cell-restored immunodeficient hosts increased Th17 cell responses in the intestine and led to exacerbation of colitis. These results identify a monocyte-derived inflammatory DC subset that is associated with the pathogenesis of intestinal inflammation, providing a therapeutic target for the treatment of inflammatory bowel disease.

VE-cadherin regulates migration inhibitory factor synthesis and release.

OBJECTIVE: Vascular endothelial (VE)-cadherin-mediated adherens junction is critical to maintain endothelial integrity. Besides its role of homophilic intercellular adhesion, VE-cadherin also has a role of outside-in signaling with functional consequences for vascular physiology. However, the nature of these signals remains not completely understood. MATERIALS AND METHODS: Human umbilical vein endothelial cells (HUVECs) were used in cell culture experiments. Confluent HUVECs were treated with VE-cadherin function-blocking antibodies BV9 (50 µg/ml) or IgG control. Antibody array was used to screen for cytokine/chemokine in supernatant. For VE-cadherin knockdown, siRNA transfection was used. ELISA, Western blot, and qRT-PCR were used to confirm the expression of screened cytokine/chemokine. To explore the possible mechanisms, Scr phosphorylation was detected and Scr inhibitor PP2 (1 µM) was used. To investigate in vivo relevance of the findings, BV9 and the indicated neutralizing antibodies were injected into mice and then lung vascular leak and inflammation were examined by Evans blue assay and lung tissue H&E, respectively. RESULTS: Using a non-biased, high-throughout human cytokine/chemokine antibody array, we first found that disruption of VE-cadherin-mediated adhesion by function-blocking antibody BV9 triggered the release of migration inhibitory factor (MIF). This VE-cadherin-mediated release of MIF further confirmed by ELISA with both VE-cadherin blocking antibody and siRNA technique was due to enhanced expression of MIF mRNA, which was mediated by Src kinase activation. In addition, in vivo lung vascular leak induced by VE-cadherin function-blocking antibody was partly alleviated by neutralizing MIF. CONCLUSIONS: VE-cadherin regulates MIF synthesis and release via Src kinase. Our data provide additional evidence to the concept that VE-cadherin transfers intracellular signals to coordinate the state of cell-cell adhesion with gene expression.