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Angioimmunoblastic T-cell lymphoma (AITL) is a T-cell lymphoma of follicular helper T-cell origin. Histologically, neoplastic T-cells proliferate to form clusters adjacent to or between arborizing high endothelial venules (HEVs). HEVs in normal lymph nodes express sulfated glycans called peripheral lymph node addressin (PNAd); however, it remains unclear whether PNAd is also expressed on HEVs in AITL. Furthermore, although it is widely accepted that HEVs are conspicuous in AITL due to their proliferation, quantitative histological support for this concept is lacking. To investigate these issues, we employed monoclonal antibodies recognizing PNAd, namely, MECA-79, HECA-452, and 297-11A, and performed quantitative immunohistochemical analysis of HEVs in 36 AITL-affected and 67 normal lymph nodes. Staining with all three antibodies confirmed that AITL HEVs express PNAd. Moreover, AITL HEVs were bound calcium-dependently by L-selectin-IgM fusion proteins, indicating that they function in the recruitment of L-selectin-expressing lymphocytes. Unexpectedly, HEV distribution density was not increased but rather decreased in AITL compared with normal lymph nodes, but HEV cross-sectional area in AITL was significantly greater than that seen in normal lymph nodes. Overall, these results indicate that the prominence of AITL HEVs is likely due to increased cross-sectional area rather than increased distribution density.

In the last two decades, understanding of inflammatory bowel disease (IBD) immunopathogenesis has expanded considerably. Histopathological examination of the intestinal mucosa in IBD demonstrates the presence of a chronic inflammatory cell infiltrate. Research has focused on identifying mechanisms of immune cell trafficking to the gastrointestinal tract that may represent effective gut-selective targets for IBD therapy whilst avoiding systemic immunosuppression that may be associated with off-target adverse effects such as infection and malignancy. Integrins are cell surface receptors that can bind to cellular adhesion molecules to mediate both leukocyte homing and retention. In 2014, Vedolizumab (Entyvio®) was the first anti-integrin (anti-α4s7 monoclonal antibody) treatment to be approved for use in IBD. Several other anti-integrin therapies are currently in advanced stages of development, including novel orally administered small-molecule drugs. Drugs targeting alternative trafficking mechanisms such as mucosal addressin cellular adhesion molecule-1 and sphingosine-1-phosphate receptors are also being evaluated. Here, we summarise key established and emerging therapies targeting leukocyte trafficking that may play an important role in realising the goal of stratified precision medicine in IBD care.

Background Patients with Crohn’s disease (CD) experience intestinal inflammation. Ontamalimab (SHP647), a fully human immunoglobulin G2 monoclonal antibody against mucosal addressin cell adhesion molecule-1, is a potential novel CD treatment. OPERA II, a multicenter, open-label, phase 2 extension study, assessed the long-term safety and efficacy of ontamalimab in patients with moderate-to-severe CD. Methods Patients had completed 12 weeks of blinded treatment (placebo or ontamalimab at 22.5, 75, or 225 mg subcutaneously) in OPERA (NCT01276509) or had a clinical response to ontamalimab 225 mg in TOSCA (NCT01387594). Participants received ontamalimab at 75 mg every 4 weeks (weeks 0–72), then were followed up every 4 weeks for 24 weeks. One-time dose reduction to 22.5 mg or escalation to 225 mg was permitted at the investigator’s discretion. The primary end points were safety and tolerability outcomes. Secondary end points included changes in serum drug and biomarker concentrations. Efficacy end points were exploratory, and used non-responder imputation methods. Results Overall, 149/268 patients completed the study. The most common adverse event leading to study discontinuation was CD flare (19.8%). Two patients died; neither death was considered to be drug related. No dose reductions occurred; 157 patients had their dose escalated. Inflammatory biomarker concentrations decreased. Serum ontamalimab levels were consistent with known pharmacokinetics. Remission rates (Harvey-Bradshaw Index [HBI] ≤ 5; baseline, 48.1%; week 72, 37.3%) and response rates (baseline [decrease in Crohn’s Disease Activity Index ≥ 70 points], 63.1%; week 72 [decrease in HBI ≥ 3], 42.5%) decreased gradually. Conclusions Ontamalimab was well tolerated; treatment responses appeared to be sustained over 72 weeks. ClinicalTrials.gov ID: NCT01298492.

Prior literature suggests that self-transcendence (other-oriented) values may be a primary mechanism for moving beyond transitory feelings of empathy toward a compassionate orientation to addressing structural injustice. Active learning techniques in the classroom may then offer a fruitful platform for students to engage in the critical reflection connected to both values and compassion. This study uses a quasi-experimental pretest/posttest survey design to investigate the relationship among values, compassion, and active learning in a college-level Introduction to Sociology course. Student interviews conducted after semester completion are also used to explore the extent to which effects may persist beyond the conclusion of a course. Analyses suggest that exposure to active learning exercises as part of sociology course material results in a measurable shift toward self-transcendence and an increase in compassionate orientation, and values partially mediate this effect.

Extra-intestinal manifestations (EIMs) of the eyes are found in IBD patients, but the underlying pathogenesis remains unknown. To investigate the pathogenesis of IBD-associated retinal dysfunction, chronic colitis was induced in mice by oral administration of dextran sodium sulfate (DSS). Electroretinography (ERG) was performed to evaluate retinal function. Retinal neuron degeneration was analyzed by immunohistochemistry. Colitic mice displayed aberrant amplitudes of ERG a-, b-wave and oscillatory potentials (OP). Importantly, we observed severe degeneration of bipolar and ganglion cells. In contrast, outer retinal neurons (mainly photoreceptor cells) are mildly affected by colitis. Moreover, retinal inflammatory responses were significantly upregulated during colitis, including microglia activation, lymphocyte infiltration and cytokine/chemokine production. Notably, mucosal addressin cell adhesion molecule 1 (MAdCAM-1) was upregulated in retinal microvessels, especially the superficial and deep plexuses, and recruited gut-homing CD4+ T cells to be co-localized with bipolar and ganglion cells during colitis. Expectedly, in vivo depletion of CD4+ T cells or blockade of MAdCAM-1 greatly alleviated colitis-induced retinal inflammatory responses and neuron degeneration. Therefore, our data provide novel insight into the pathogenesis of IBD-associated retinal dysfunction, and targeted immune therapy directly against MAdCAM-1 might provide a novel approach in the management of eye EIM of IBD.

Background: Vedolizumab is a humanized immunoglobulin G1 monoclonal antibody, which binds to α4β7 integrin on T lymphocytes, thus disturbing the interaction with mucosal vascular addressin cell adhesion molecule 1 on the intestinal endothelial cells to interfere with lymphocyte trafficking to the gut. Summary: Vedolizumab is a safe and effective drug to induce and maintain clinical remission in patients with Crohn’s disease (CD) and ulcerative colitis (UC) in both clinical trials and real-world data. Various guidelines recommend vedolizumab as a first- or second-line treatment regimen for steroid-dependent, steroid, or immunomodulator refractory cases of UC and CD; however, it is more effective in anti-TNF-naive patients. The first head-to-head trial (VARSITY trial) comparing the efficacy of vedolizumab to adalimumab has shown better clinical remission and mucosal healing with vedolizumab. Key Messages: In this review, we have discussed guidelines recommendation of vedolizumab use, as well as its safety data, use in special population, in presence of extraintestinal complications, therapeutic drug monitoring, data from Asian patients, along with other evolving concepts. Because of its excellent safety data and low immunogenicity, vedolizumab is an impressive option for patients with prior malignancy and less chance of reactivation of tuberculosis; however, cost remains an issue.

Acute HIV infection is characterized by rapid viral seeding of immunologic inductive sites in the gut followed by the severe depletion of gut CD4(+) T cells. Trafficking of α(4)β(7)-expressing lymphocytes to the gut is mediated by MAdCAM, the natural ligand of α(4)β(7) that is expressed on gut endothelial cells. MAdCAM signaling through α(4)β(7) costimulates CD4(+) T cells and promotes HIV replication. Similar to MAdCAM, the V2 domain of the gp120 HIV envelope protein binds to α(4)β(7). In this study, we report that gp120 V2 shares with MAdCAM the capacity to signal through α(4)β(7) resulting in CD4(+) T cell activation and proliferation. As with MAdCAM-mediated costimulation, cellular activation induced by gp120 V2 is inhibited by anti-α(4)β(7) monoclonal antibodies (mAbs). It is also inhibited by anti-V2 domain antibodies including nonneutralizing mAbs that recognize an epitope in V2 that has been linked to reduced risk of acquisition in the RV144 vaccine trial. The capacity of the V2 domain of gp120 to mediate signaling through α(4)β(7) likely impacts early events in HIV infection. The capacity of nonneutralizing V2 antibodies to block this activity reveals a previously unrecognized mechanism whereby such antibodies might impact HIV transmission and pathogenesis.

Purpose Assessment of inflammatory bowel disease (IBD) currently relies on aspecific clinical signs of bowel inflammation. Specific imaging of the diseased bowel regions is still lacking. Here, we investigate mucosal addressin cell adhesion molecule 1 (MAdCAM-1) as a reliable and specific endothelial target for engineered nanoparticles delivering imaging agents to obtain an exact mapping of diseased bowel foci. Materials and Methods We generated a nanodevice composed of PLGA-PEG coupled with anti-MAdCAM-1 antibody half-chains and loaded with quantum dots (P@QD-MdC NPs). Bowel localization and systemic biodistribution of the nanoconjugate were analyzed upon injection in a murine model of chronic IBD obtained through repeated administration of dextran sulfate sodium salt. Specificity for diseased bowel regions was also assessed ex vivo in human specimens from patients with IBD. Potential for development as contrast agent in magnetic resonance imaging was assessed by preliminary study on animal model. Results Synthesized nanoparticles revealed good stability and monodispersity. Molecular targeting properties were analyzed in vitro in a cell culture model. Upon intravenous injection, P@QD-MdC NPs were localized in the bowel of colitic mice, with enhanced accumulation at 24 h post-injection compared to untargeted nanoparticles (p

Ontamalimab (SHP647) is a fully human, immunoglobulin G2, antihuman mucosal addressin cell adhesion molecule‐1 (MAdCAM‐1) monoclonal antibody being developed for the treatment of ulcerative colitis (UC) and Crohn's disease (CD). A population pharmacokinetic/pharmacodynamic (PK/PD) analysis was conducted using clinical phase 2 study data to evaluate the PK and PD of ontamalimab following subcutaneous administrations of 7.5, 22.5, 75, and 225 mg every 4 weeks in patients with moderate to severe UC or CD. A total of 440 patients with UC (n = 249; 56.6%) or CD (n = 191; 43.4%) were included in the analysis. A 2‐compartment model with parallel linear and nonlinear elimination adequately characterized concentration‐time profiles of ontamalimab. The apparent clearance and volume of distribution were 0.0127 L/h (0.305 L/day) and 6.53 L, respectively. Apparent clearance and volume of distribution were mainly dependent on baseline albumin and body weight, respectively. No differences in the PK properties of ontamalimab were observed between patients with UC or CD. The presence of antidrug antibodies did not impact the PK of ontamalimab. Nonlinear elimination occurred at very low concentrations and was unlikely to contribute to the elimination half‐life under steady‐state conditions. A linear PK/PD model described the relationship between ontamalimab and free MAdCAM‐1. Minimum concentrations of ontamalimab at steady state following 75 mg every 4 weeks were associated with >95% suppression of circulating free MAdCAM‐1. The PK/PD properties characterized support phase 3 testing in UC and CD.

Background/Aims: PF-00547659 is a monoclonal antibody against human mucosal addressin cell adhesion molecule-1 (MAd CAM-1) that prevents the binding of α4β7+ lymphocytes to MAdCAM-expressing sites in the gastrointestinal tract with high af finity and selectivity, and is being developed for the treatment of Crohn’s disease (CD). Methods: OPERA is a randomized, mul ticenter, double-blind, placebo-controlled study to investigate the efficacy, safety, and pharmacokinetics of PF-00547659 fol lowing subcutaneous administration in subjects with active CD, a history of failure or intolerance to anti-tumor necrosis factor and/or immunosuppressants, high-sensitivity C-reactive protein >3.0 mg/L, and ulcers on colonoscopy. The primary endpoint was Crohn’s Disease Activity Index-70 response at week 8 or 12. Subpopulation analyses for Asian subjects were performed as some differences are observed in genetics and clinical phenotypes in Asian CD patients compared with Western patients. Results: In this study, 265 CD subjects were randomized, with a subpopulation of 21 subjects (8 Japanese and 13 Korean) de fined as the Asian population. In the overall and Asian populations; PF-00547659 was pharmacologically active as evidenced by soluble MAdCAM and circulating β7+ central memory CD4+ T-lymphocytes, although no clear evidence of efficacy was observed in any clinical endpoints; pharmacokinetics of PF-00547659 in the Asian subpopulation was generally comparable to the overall population; and the safety profile of PF-00547659 appeared acceptable up to 12 weeks of treatment. Conclusions: In the overall and Asian populations, efficacy of PF-00547659 could not be demonstrated using any clinical endpoints compared with placebo. Pharmacokinetics and safety of PF-00547659 were generally comparable. Further studies with larger numbers of patients are required to confirm our results. (Trial Registration Number: NCT01276509) (Intest Res 2020;18:45-55)

Background & Aims: Integrin α4β7 mediates lymphocyte trafficking to the gut and gut-associated lymphoid tissues, a process critical for recruitment of effector lymphocytes from the circulation to the gut mucosa in inflammatory bowel disease (IBD) and murine models of intestinal inflammation. Antibody blockade of β7 integrins generally is efficacious in IBD; however, some patients fail to respond, and a few patients can experience exacerbations. This study examined the effects of loss of β7 integrin function in murine models of IBD. Methods: In a mouse IBD model caused by lack of interleukin 10, a cytokine important in CD25hiFoxP3+ regulatory T cell (Treg) function, genetic deletion of β7 integrin or antibody blockade of α4β7–mucosal addressin cell adhesion molecule-1 interaction paradoxically exacerbated colitis. Results: Loss of β7 impaired the capacity of Tregs homing to the gut and therefore suppress intestinal inflammation in an adoptive T-cell transfer model; however, the intrinsic suppressive function of β7-deficient Tregs remained intact, indicating that the β7 deficiency selectively impacts gut homing. Deletion of β7 integrin did not worsen colitis in an acute dextran sodium sulfate model in which Treg number and function were normal. Conclusions: In Integrin subunit beta (Itgb)7-/-Il10-/- mice, loss of β7-dependent Treg homing to gut-associated lymphoid tissues combined with loss of intrinsic Treg function exacerbated intestinal inflammation. These results suggest that IBD patients with reduced CD25hiFoxP3+ Treg numbers or function or lack of interleukin 10 could be at risk for failure of α4β7 blocking therapy. Keywords: Integrin β7 Blockade, Inflammatory Bowel Disease, Regulatory T Cells, Gut-Associated Lymphoid Tissue

The antigenic heterogeneity of the reticular framework of the white pulp and marginal zone is well documented in the human adult spleen. Immunostaining of α-smooth muscle actin characterizes the heterogeneity of the reticular framework of the white pulp and marginal zone. In the human spleen, the blood cells flow in an open circulation. T and B lymphocytes flow out from the arterial terminal, and migrate in the reticular framework. Homing of lymphocytes to lymphoid tissues is regulated by selective interactions between cell surface homing receptors and tissue vascular addressins at sites of lymphocyte recruitment from the blood. In the present study, mucosal addressin cell adhesion molecule-1 was selectively expressed on α-smooth muscle actin-positive reticular framework. The reticular framework may function in lymphocyte homing and segregation into the periarteriolar lymphoid sheath, lymph follicle and marginal zone.

Plaque psoriasis (PSO) and lichen planus (LP) are skin diseases with some similarities in pathogenesis, comorbidities, and clinical presentation. Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) and its ligand, α4β7 integrin, are involved in inflammatory bowel diseases and liver dysfunctions, which occur more frequently in PSO and LP. Serum MAdCAM-1 and ITGB7 levels in patients with plaque PSO and eruptive LP have never been studied before. The study included 42 patients with PSO, 13 with LP, and 23 controls. Serum molecules levels were evaluated using the immune–enzymatic method. ITGB7 concentration was not statistically different, both in patients with PSO and LP, compared to controls (both p &gt, 0.05). MAdCAM-1 level was significantly lower in PSO subjects than in controls (p = 0.041), whereas in the LP group, a downward trend was observed (p = 0.088) with p = 0.0455 in ANOVA. Multiple linear regression revealed independent associations between ITGB7 and HDL and BMI and RBC in the LP group. In psoriatic patients with elevated CRP, there was an upward trend for MAdCAM-1, and also a positive correlation between MAdCAM-1 and WBC. ITGB7 and MAdCAM-1 cannot serve as markers of disease activity or liver pathology neither in patients with PSO nor LP. MAdCAM-1 might play a role as an inflammation indicator in PSO and a beneficial influence on the lipid profile in LP.

Background and Aims Some patients with ulcerative colitis [UC] do not respond to vedolizumab treatment despite adequate drug exposure in serum. This study aimed to investigate vedolizumab in tissue and questioned whether insufficient tissue exposure could explain non-response in UC patients with adequate serum vedolizumab concentrations. Methods A paired serum sample and colonic mucosal biopsy was collected from 40 UC patients [20 endoscopic responders, 20 non-responders] at week 14 of vedolizumab treatment. Vedolizumab, soluble [s]-mucosal addressin cell adhesion molecule-1 [MAdCAM-1], s-vascular cell adhesion molecule-1 [VCAM-1] and s-intercellular adhesion molecule-1 [ICAM-1] were measured in serum and/or tissue. Endoscopic response was defined as Mayo endoscopic sub-score ≤1. Results A significant positive correlation was observed between vedolizumab serum and colonic tissue concentrations [ρ = 0.84, p < 0.0001], regardless of the macroscopic inflammatory state of the tissue. Vedolizumab tissue concentrations were lower in non-responders than in responders [0.07 vs 0.11 µg/mg, p = 0.04]. In the subgroup of patients with adequate vedolizumab serum concentrations [>14.6 µg/mL], tissue vedolizumab was not significantly different between responders and non-responders [0.15 vs 0.13 µg/mg; p = 0.92]. Serum sMAdCAM-1 concentrations, but not serum sICAM-1 or sVCAM-1 concentrations, were significantly higher in responders than in non-responders with adequate vedolizumab serum concentrations [1.04 vs 0.83 ng/mL, p = 0.03]. Conclusions Vedolizumab concentrations in colonic mucosal tissue of UC patients reflect the concentration in serum regardless of the macroscopic inflammatory state of the tissue. Our data show that insufficient tissue exposure does not explain non-response in UC patients with adequate serum vedolizumab concentrations.

IMPORTANCE Recent studies positing the gut as a sanctuary site for viral persistence in SARS-CoV-2 infection highlight the importance of assimilating profiles of systemic as well as gut inflammatory mediators to understand the pathology of COVID-19. Also, the role of these markers in governing virus specific immunity following infection remains largely unexplored. OBJECTIVE To evaluate the role of systemic and gut inflammatory markers in disease progression and development of anti-viral humoral immunity following SARS-CoV-2 infection. DESIGN, SETTING AND PARTICIPANTS This cohort study (n=58) of SARS-CoV-2 infected individuals included a group of in-patients (n=36) at various stages of disease progression together with convalescent individuals (n=22) recruited between April and June 2020 (peak of the epidemic) from a tertiary care hospital in Mumbai, India. Follow-up of 11 in-patients at day 7 post diagnosis was carried out, resulting in a total of 47 in-patient samples. EXPOSURES Diagnosis of SARS-CoV-2 infections was confirmed by reverse transcriptase–polymerase chain reaction-based testing of nasopharyngeal/oropharyngeal samples. MAIN OUTCOMES AND MEASURES Primary outcomes were the measurement of inflammatory markers including Th1/Th2/Th17 cytokines and levels of soluble mucosal addressin cell adhesion molecule (sMAdCAM) in plasma. Anti-viral humoral response was measured by rapid antibody test (IgG, IgM) and chemiluminescent immunoassay (CLIA) (IgG). Also antibodies binding to SARS-CoV-2 proteins were measured by surface plasmon resonance (SPR). Secondary outcomes were correlation of the inflammatory signature with clinical information, including age, sex, disease duration and co-morbidities. RESULTS Twenty eight of 36 (78%) in-patients and 19 of 22 (86%) convalescents were males. Out of 47 in-patient samples, 22 (46%), 11 (23%) and 14 (30%) were IgG-/IgM-, IgG+/IgM+ and IgG+/IgM-respectively. Of 22 convalescent samples, 3 (14%), 1 (4%) and 17 (77%) were respectively IgG-/IgM-, IgG+/IgM+ and IgG+/IgM-. Two out of 22 (9%) convalescents showed high IL-6 levels (>100pg/ml) and 4 (18%) had high TNF levels (>30pg/ml). However, the convalescents (n =22) had significantly lower levels of IL-6 [Median=27.48 (IQR=23.54-39.92)] compared to followed up in-patients (n = 11) at day 0 [Median=111(IQR=68-129.7), p =0.0002] and higher levels of sMAdCAM [Median=1940 (1711-2174) pg/ml] compared to these individuals at day 0 [Median=1701 (IQR=1532-1836) pg/ml; p=0.032] and day 7 [Median=1534 (IQR=1236-1654) pg/ml; p=0.0007]. Further, IL-6 and sMAdCAM levels among in-patients inversely correlated with one another (r = −0.374, p = 0.009, CI = 95%). When expressed as a novel integrated marker –sMIL (sMAdCAM/IL-6 ratio) index, these levels were incrementally and significantly higher across various disease states with convalescents exhibiting the highest values [Median= 64.74 (IQR=47.33-85.58)]. Also, the sMIL index was significantly higher in convalescents (with class-switched responses) compared to IgG+/IgM+ individuals at early stages of infection [Median=28.65 (IQR=13.63-96.26), p = 0.034]. Real-time measurement by SPR of plasma antibody binding to viral nucleocapsid (NC), receptor binding domain (RBD) and spike (S) revealed waxing and waning of plasma antibody responses to all 3 targets. Importantly, sMAdCAM levels as well as sMIL index (fold change) correlated with peak association rates of RBD-binding (r = 0.462, p = 0.03, CI = 95%) and fold change in binding to S (r = 0.68, p = 0.050, CI = 95%) respectively. CONCLUSION AND RELEVANCE Our results highlight key systemic and gut-associated immune parameters that need to be monitored and investigated further to optimally guide therapeutic and prophylactic interventions for COVID-19. KEY POINTS Question Do systemic and gut inflammatory mediators play a role in disease progression as well as development of antiviral responses in SARS-CoV-2 infection? Findings IL-6 and sMAdCAM expressed as a novel integrative marker (sMIL index) are associated both with disease-states (early infection and convalescence) as well as development of antiviral humoral responses. Meaning Further investigation into the utility of using sMIL index as a biomarker for disease progression and recovery, including the development of potentially neutralizing antiviral responses is warranted.

In some organs, such as the brain, endothelial cells form a robust and highly selective blood-to-tissue barrier. However, in other organs, such as the intestine, endothelial cells provide less stringent permeability, to allow rapid exchange of solutes and nutrients where needed. To maintain the structural and functional integrity of the highly dynamic blood–brain and gut–vascular barriers, endothelial cells form highly specialized cell-cell junctions, known as adherens junctions and tight junctions. Claudins are a family of four-membrane-spanning proteins at tight junctions and they have both barrier-forming and pore-forming properties. Tissue-specific expression of claudins has been linked to different diseases that are characterized by barrier impairment. In this review, we summarize the more recent progress in the field of the claudins, with particular attention to their expression and function in the blood–brain barrier and the recently described gut–vascular barrier, under physiological and pathological conditions. Abbreviations: 22q11DS 22q11 deletion syndrome; ACKR1 atypical chemokine receptor 1; AD Alzheimer disease; AQP aquaporin; ATP adenosine triphosphate; Aβ amyloid β; BAC bacterial artificial chromosome; BBB blood-brain barrier; C/EBP-α CCAAT/enhancer-binding protein α; cAMP cyclic adenosine monophosphate (or 3ʹ,5ʹ-cyclic adenosine monophosphate); CD cluster of differentiation; CNS central nervous system; DSRED discosoma red; EAE experimental autoimmune encephalomyelitis; ECV304 immortalized endothelial cell line established from the vein of an apparently normal human umbilical cord; EGFP enhanced green fluorescent protein; ESAM endothelial cell-selective adhesion molecule; GLUT-1 glucose transporter 1; GVB gut-vascular barrier; H2B histone H2B; HAPP human amyloid precursor protein; HEK human embryonic kidney; JACOP junction-associated coiled coil protein; JAM junctional adhesion molecules; LYVE1 lymphatic vessel endothelial hyaluronan receptor 1; MADCAM1 mucosal vascular addressin cell adhesion molecule 1; MAPK mitogen-activated protein kinase; MCAO middle cerebral artery occlusion; MMP metalloprotease; MS multiple sclerosis; MUPP multi-PDZ domain protein; PATJ PALS-1-associated tight junction protein; PDGFR-α platelet-derived growth factor receptor α polypeptide; PDGFR-β platelet-derived growth factor receptor β polypeptide; RHO rho-associated protein kinase; ROCK rho-associated, coiled-coil-containing protein kinase; RT-qPCR real time quantitative polymerase chain reactions; PDGFR-β soluble platelet-derived growth factor receptor, β polypeptide; T24 human urinary bladder carcinoma cells; TG2576 transgenic mice expressing the human amyloid precursor protein; TNF-α tumor necrosis factor α; WTwild-type; ZO zonula occludens.

Muscovy duck reovirus (MDRV) causes serious immunodeficiency in the intestinal mucosa, although the underlying histopathological mechanisms remain unclear. Thus, we investigated the impact of MDRV infection on intestinal morphology using hematoxylin and eosin staining. Immune-related cells were also quantified by staining with hematoxylin and eosin, toluidine blue, and periodic acid-Schiff stain, or by immunohistochemistry and cytochemistry for lectin. Similarly, CD4+ and CD8+ cells were quantified by flow cytometry, and the expression of several immune-related molecules was quantified by radioimmunoassay. We found that MDRV clearly damaged the intestinal mucosa, based on tissue morphology, villus length, villus width, intestinal thickness, villus height/crypt depth ratio, and villus surface area. MDRV also altered the density or distribution of lymphocytes, mastocytes, and goblet cells in the small intestinal mucosa, as well as microfold cells in Peyer's patches. In addition, MDRV markedly depleted CD4+ cells from the intestinal mucosa and lowered the CD4+:CD8+ ratio in peripheral blood. Moreover, MDRV diminished the levels of secretory IgA and mucosal addressin cell adhesion molecule-1 (p < 0.01), but elevated those of histamine and nitric oxide (p < 0.01 or p < 0.05). Finally, MDRV significantly suppressed IL-1β, IL-4, IL-5, and IL-8 levels (p < 0.01 or p < 0.05) mid-infection. Collectively, our data suggest that MDRV severely damages the structure and function of the intestinal mucosa by modulating immune cells and immune-related factors, thus leading to local immunodeficiency. Our findings lay the foundation for further research on the pathogenesis of MDRV.

Background and Aims To define pharmacodynamic and efficacy biomarkers in ulcerative colitis [UC] patients treated with PF-00547659, an anti-human mucosal addressin cell adhesion molecule-1 [MAdCAM-1] monoclonal antibody, in the TURANDOT study. Methods Transcriptome, proteome and immunohistochemistry data were generated in peripheral blood and intestinal biopsies from 357 subjects in the TURANDOT study. Results In peripheral blood, C-C motif chemokine receptor 9 [CCR9] gene expression demonstrated a dose-dependent increase relative to placebo, but in inflamed intestinal biopsies CCR9 gene expression decreased with increasing PF-00547659 dose. Statistical models incorporating the full RNA transcriptome in inflamed intestinal biopsies showed significant ability to assess response and remission status. Oncostatin M [OSM] gene expression in inflamed intestinal biopsies demonstrated significant associations with, and good accuracy for, efficacy, and this observation was confirmed in independent published studies in which UC patients were treated with infliximab or vedolizumab. Compared with the placebo group, intestinal T-regulatory cells demonstrated a significant increase in the intermediate 22.5-mg dose cohort, but not in the 225-mg cohort. Conclusions CCR9 and OSM are implicated as novel pharmacodynamic and efficacy biomarkers. These findings occur amid coordinated transcriptional changes that enable the definition of surrogate efficacy biomarkers based on inflamed biopsy or blood transcriptomics data. ClinicalTrials.gov identifier NCT01620255

Purpose of review Trafficking of lymphocytes into and between gut inductive and effector sites of the gut tissues is regulated by integrin α4β7. Recent findings that describe the central role of α4β7 CD4 T cells in HIV pathogenesis, and the possibility of targeting these cells to prevent or treat HIV infection will be reviewed. Recent findings Recent reports indicate that the frequency of α4β7 CD4 T cells is directly correlated with the risk of HIV acquisition and CD4 T-cell decline post infection. MAdCAM -mediated signaling through α4β7, in the presence of retinoic acid, supports viral replication in recently activated naive CD4 T cells. Treatment of HIV-infected patients with vedolizumab, an α4β7 antagonist, is well tolerated, and reduces the size and number of lymphoid aggregates in gut associated lymphoid tissues. Summary Integrin α4β7 underlies one of the principal mechanisms that CD4 T cells employ to traffic to the gut. It also defines a subset of cells that play a significant role in HIV transmission and pathogenesis. Understanding how α4β7 facilitates gut homing may provide insight into key aspects of HIV transmission, pathogenesis, and the formation of viral reservoirs. Targeting α4β7 may have utility in the prevention and treatment of HIV infection.

Immune cell dysregulation and lymphopenia characterize COVID-19 pathology in moderate to severe disease. While underlying inflammatory factors have been extensively studied, homeostatic and mucosal migratory signatures remain largely unexplored as causative factors. In this study we evaluated the association of circulating IL-6, soluble mucosal addressin cell adhesion molecule (sMAdCAM) and IL-15 with cellular dysfunction characterizing mild and hypoxemic stages of COVID-19. A cohort of SARS-CoV-2 infected individuals (n=125) at various stages of disease progression together with healthy controls (n=16) were recruited from COVID Care Centres (CCCs) across Mumbai, India. Multiparametric flow cytometry was used to perform in-depth immune subset characterization and to measure plasma IL-6 levels. sMAdCAM, IL-15 levels were quantified using ELISA. Distinct depletion profiles, with relative sparing of CD8 effector memory and CD4+ regulatory T cells was observed in hypoxemic disease within the lymphocyte compartment. An apparent increase in the frequency of intermediate monocytes characterized both mild as well as hypoxemic disease. IL-6 levels inversely correlated with those of sMAdCAM and both markers showed converse associations with observed lympho-depletion suggesting opposing roles in pathogenesis. Interestingly, IL-15, a key cytokine involved in lymphocyte activation and homeostasis, was detected in symptomatic individuals but not in healthy controls or asymptomatic cases. Further, negative association of plasma IL-15 with depleted T, B and NK subsets suggested a compensatory production of this cytokine in response to the profound lymphopenia. Finally, higher levels of plasma IL-15 and IL-6, but not sMAdCAM, were associated with longer duration of hospitalization.

Lymphocyte homing, trafficking and recirculation ensures maximum contact and interaction of cells with antigen, and correct homing of lymphocytes to appropriate lymphoid microenviromnents. Lymphocytes remain in the blood 2–12 h before homing to organs. Most leukocyte migration occurs across venules (e.g. lymphocytes cross high endothelial venules). The cells migrate for several reasons. These include migration of mononuclear cells into chronic inflammatory sites in response to chemotaxins, migration of activated lymphocytes into inflammatory sites, migration of neutrophils into sites of acute immune response and migration of lymphocytes into secondary lymphoid organs (spleen, lymph nodes). The adherence and movement of cells through the vascular and endothelial spaces, in response to chemotactic factors, chemokines, antigens, or as a result of inflammation is called extravasation (also called diapedisis or transendothelial migration). This process is highly regulated. The cytokines IL-1, IFNγ, and TNFα influence the expression of cell adhesion molecules (CAMs) and vascular addressins (VAs). Lymphocyte homing is influenced by the state of cell activation, for example, the homing properties of naive cells, effector cells and memory cells is different. CAMs expressed by endothelial cells interact with receptors (CAM receptors) on leukocytes to aid the process of cell migration and extravasation. The pattern of cell migration depends on CAMs such as selectins and is also aided by chemokines. A rolling mechanism of migration and diapedesis is used by neutrophils. Neutrophils respond and move up a chemokine gradient as they respond and migrate to sites of inflammation. The chemokine CXCL8 (IL-8) is an important chemoattractant for neutrophils responding to the concentration gradient of the chemokine. Leukocyte adhesion deficiency (LAD) results from a lack of expression of integrins. Leukocytes are not able to diapedese out of the blood vessels into tissue. Neutrophils and monocytes recruited to sites of infection and inflammation remain within the blood vessels. Skin window tests such as the Rebuck skin window test show a failure of leukocyte migration to a site of superficial skin abrasion. In the absence of LAD, such a skin abrasion would result in the accumulation of leukocytes such as neutrophils and monocytes. Individuals with LAD experience recurrent bacterial infections.

The homing of lymphocytes from blood to gut-associated lymphoid tissue is regulated by interaction between integrin α4β7 with mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) expressed on the endothelium of high endothelial venules (HEVs). However, the molecular basis of mucin-like domain, a specific structure of MAdCAM-1 regulating integrin α4β7-mediated cell adhesion remains obscure. In this study, we used heparan sulfate (HS), which is a highly acidic linear polysaccharide with a highly variable structure, to mimic the negative charges of the extracellular microenvironment and detected the adhesive behaviors of integrin α4β7 expressing 293T cells to immobilized MAdCAM-1 in vitro. The results showed that HS on the surface significantly promoted integrin α4β7-mediated cell adhesion, decreased the percentage of cells firmly bound and increased the rolling velocities at high wall shear stresses, which was dependent on the mucin-like domain of MAdCAM-1. Moreover, breaking the negative charges of the extracellular microenvironment of CHO-K1 cells expressing MAdCAM-1 with sialidase inhibited cell adhesion and rolling velocity of 293T cells. Mechanistically, electrostatic repulsion between mucin-like domain and negative charges of the extracellular microenvironment led to a more upright conformation of MAdCAM-1, which facilitates integrin α4β7-mediated cell adhesion. Our findings elucidated the important role of the mucin-like domain in regulating integrin α4β7-mediated cell adhesion, which could be applied to modulate lymphocyte homing to lymphoid tissues or inflammatory sites.

Vedolizumab has become an integral part of the therapeutic armamentarium for patients with inflammatory bowel disease (IBD) who have failed conventional medical therapy. Vedolizumab is an α4β7 integrin antagonist that inhibits intestinal T-cell translocation by blocking integrin interactions with mucosal vascular addressin cellular adhesion molecule 1, reducing lymphocyte-mediated inflammation.1 Its gut selective mode of action and favorable safety profile have led to reports of off-label use for non-IBD-related inflammatory intestinal disorders, such as microscopic colitis,2 and small intestinal inflammatory conditions including autoimmune enteropathy3 and common variable immune deficiency-related enteritis.4 Treatment of non-IBD-related enteropathies is challenging with no approved therapies or established treatment algorithms. We conducted a literature review to assess clinical, endoscopic, and histologic improvement in patients treated with vedolizumab for non-IBD enteropathies refractory to conventional therapy.

Background & Aims The heterodimeric integrin receptor α4β7 regulates CD4 T cell recruitment to inflamed tissues, but its role in the pathogenesis of non-alcoholic steatohepatitis (NASH) is unknown. Herein, we examined the role of α4β7-mediated recruitment of CD4 T cells to the intestine and liver in NASH. Methods Male littermate F11r+/+ (control) and junctional adhesion molecule A knockout F11r−/− mice were fed a normal diet or a western diet (WD) for 8 weeks. Liver and intestinal tissues were analyzed by histology, quantitative reverse transcription PCR (qRT-PCR), 16s rRNA sequencing and flow cytometry. Colonic mucosa-associated microbiota were analyzed using 16s rRNA sequencing. Liver biopsies from patients with NASH were analyzed by confocal imaging and qRT-PCR. Results WD-fed knockout mice developed NASH and had increased hepatic and intestinal α4β7+ CD4 T cells relative to control mice who developed mild hepatic steatosis. The increase in α4β7+ CD4 T cells was associated with markedly higher expression of the α4β7 ligand mucosal addressin cell adhesion molecule 1 (MAdCAM-1) in the colonic mucosa and livers of WD-fed knockout mice. Elevated MAdCAM-1 expression correlated with increased mucosa-associated Proteobacteria in the WD-fed knockout mice. Antibiotics reduced MAdCAM-1 expression indicating that the diet-altered microbiota promoted colonic and hepatic MAdCAM-1 expression. α4β7 blockade in WD-fed knockout mice significantly decreased α4β7+ CD4 T cell recruitment to the intestine and liver, attenuated hepatic inflammation and fibrosis, and improved metabolic indices. MAdCAM-1 blockade also reduced hepatic inflammation and fibrosis in WD-fed knockout mice. Hepatic MAdCAM-1 expression was elevated in patients with NASH and correlated with higher expression of α4 and β7 integrins. Conclusions These findings establish α4β7/MAdCAM-1 as a critical axis regulating NASH development through colonic and hepatic CD4 T cell recruitment. Lay summary Non-alcoholic steatohepatitis (NASH) is an advanced and progressive form of non-alcoholic fatty liver disease (NAFLD), and despite its growing incidence no therapies currently exist to halt NAFLD progression. Herein, we show that blocking integrin receptor α4β7-mediated recruitment of CD4 T cells to the intestine and liver not only attenuates hepatic inflammation and fibrosis, but also improves metabolic derangements associated with NASH. These findings provide evidence for the potential therapeutic application of α4β7 antibody in the treatment of human NASH.

PNAd and MAdCAM-1 addressins on venules are of importance in T-cell homing and potential therapeutic targets in ulcerative colitis (UC). Normally, PNAd+ high endothelial venules (HEVs) are only present in lymphoid organs, whereas small numbers of MAdCAM-1+ venules can be seen in non-lymphoid tissue. We aimed to study their presence in the intestinal mucosa of UC patients at diagnosis and during follow-up, and their correlation with disease activity. Colonic biopsy specimens of 378 UC patients were analyzed by immunohistochemistry for CD3, CD20, ERG, MECA-79 (PNAd) and MECA-376 (MAdCAM-1) and compared to healthy controls (HC). The proportion of PNAd+HEVs in UC at diagnosis was 4.9% (IQR 2.0%&ndash, 8.3%), while none were detected in HC. During follow-up, PNAd+HEVs completely disappeared in remission (n = 93), whereas the proportion in active disease was similar to baseline (n = 285, p = 0.39). The proportion of MAdCAM-1+venules in UC at baseline was 5.8% (IQR 2.6&ndash, 10.0). During follow-up, the proportion in remission was comparable to diagnosis, but upregulated (7.5% (IQR 4.4&ndash, 10.9), p = 0.001) in active disease. In conclusion, PNAd+HEVs appear in UC during active inflammation which could thus serve as a marker for disease activity, whereas MAdCAM-1+venules remain present after inflammation is resolved and increase after subsequent flares, reflecting chronicity and potentially serving as a therapeutic target.

Cancer is noteworthy general well-being trouble in both developed and developing nations. Cervical disease is the significant reason for tumor passing in women around the world. Chemotherapy remains the main treatment method for different malignancies. Various manufactured anticancer medications are accessible now; however, the symptoms and the medication cooperations are significant disadvantages in its clinical utility. Thus, searching a cure for cancer remains the most challenging area in the medical field. Natural products play an important role in the discovery of drug. It can be a potential drug candidate for cancer treatment. In this study, three-dimensional models of cervical cancer cell lines (tumor suppressor gene (p53), mucosal addressin cell adhesion molecule 1 (MADCAM 1) and nuclear factor NF-kappa-B-p105 subunit (NFKB 1) were generated, and the lowest binding energy with azadirachtin phytocompound was determined using local docking approach. The protein models were generated using Swiss model; their physiochemical characterization and secondary structure prediction were evaluated. After that, the protein models were validated through PROCHECK, ERRAT and Verify 3D programs. Lastly, p53, MADCAM 1 and NFKB 1 were docked successfully with azadirachtin through BSP-Slim server. The tumor suppressor gene (p53) had the strongest bond with azadirachtin due to its lowest and negative value of binding energy (2.634 kcal/mol). Azadirachtin can be a potential anticancer agent. Therefore, this protein–ligand complex structure can further be validated in the laboratory for studying its cytotoxicity on cancer cells.

Although research institutions take on increased responsibility for providing infrastructures and services around the proper handling of research data, there is no comprehensive framework addressing the ideal conditions of this implementation process. To overcome this gap, we present the DIAMANT model, a reference model aimed at providing an orientation framework for the implementation of research data management guided by the research process itself. It builds upon a central research data management information unit controlling the information flow between all other organizational units involved in research data management. Due to the possibility of outsourcing organizational units, the implementation process is maximally flexible and efficient.

Introduction The co-occurrence of inflammatory bowel disease (IBD) in up to 80% of patients with primary sclerosing cholangitis (PSC) suggests a relation between the gut and the liver in patients with both PSC and IBD. One hypothesis suggests that aberrantly expressed homing molecules in the liver drive infiltration of gut-homing memory T-cells that are originally primed in intestinal environment. One of the main findings supporting this hypothesis is the expression of mucosal addressin cell adhesion molecule 1 (MAdCAM-1) in PSC livers. Expression of homing molecules in early PSC remains unclear. The aim of this study was to investigate expression patterns of homing chemokines and adhesion molecules in PSC-IBD colons and livers, and to study whether changes are already present in early stages of PSC. Methods Needle biopsies from livers of 20 PSC patients with short-term PSC (PSC-IBDST) as well as explant liver biopsies of 8 patients with long-term PSC (PSC-IBDLT) were collected (median disease duration 0 and 22 years, respectively). Only patients with concomitant IBD were included (89% ulcerative colitis and 11% Crohn’s disease). Expression and distribution of MAdCAM-1, VAP-1, integrin β7, CCL25, CCL28, CXCL12, αE (CD103) and E-cadherin were assessed in both liver and colon tissue. Liver tissue collected from obstructive cholangitis in resection specimens for Klatskin tumors or resection specimens from hepatic metastasis, liver tissue of patients with hepatitis C virus (HCV) and of patients with primary biliary cholangitis (PBC) served as controls. Results MAdCAM-1 expression in livers of PSC-IBDLT patients was increased compared to controls. The proportion of CD3+ T-cells expressing integrin β7 did not differ between PSC-IBDST and control groups, but was higher in liver tissue of PSC-IBDLT patients. There was no difference in αE+ T-cells between PSC-IBDLT and control groups. The chemokine CCL28 was highly expressed in biliary epithelial cells. This intense staining pattern was more pronounced in PSC-IBDST, but overall did not significantly differ from controls. Conclusions We confirm that aberrant gut lymphocyte homing to the liver exists in PSC, linking gut and liver disease pathology in PSC-IBD. Our data suggests that this phenomenon increases over time in later stages of the disease, worsening ongoing inflammation., Highlights • MAdCAM-1 is aberrantly expressed in PSC-IBD liver compared to control liver. • The proportion of beta7 positive T-cells is increased in long-term PSC livers. • Biliary epithelial cells express CCL28, already in short-term PSC. • Expression patterns of inflammatory cytokines in PSC-IBD colon are not distinct from IBD.

Globally, breast cancer is one of the major cancers in females. The incident rates are increasing in recent years, particularly in developed countries. However, the lowest survival rates are found in less developed countries, because of the lack of specific symptoms at an early stage, inadequate diagnostic equipment, and lesser treatment facilities. Therefore, the development of a new cancer therapeutic approach remains the most challenging area in the medical field. Naturally derived products play a significant role in the discovery of novel drugs. It can be a potential treatment option for cancers. In this study, 3D (three-dimensional) structures of breast tumor cell proteins like p53 (a cellular cancer antigen), NF-kB (nuclear factor kappa B)-p105 subunits, and addressin, also known as MAdCAM-1 (mucosal addressin cell adhesion molecule 1) were generated, and their binding affinity with glycyrrhizin was determined through local docking. The proteins were constructed by SWISS-MODEL, and their physiochemical characters were assessed by ExPASy’s ProtParam Proteomics server. After that, they were validated by PROCHECK, ERRAT, and Verify 3D programs. Lastly, the protein structures were docked successfully with glycyrrhizin using BSP-SLIM server. The binding energy between glycyrrhizin and p53, NF-kB-p105 subunits, and MAdCAM-1 were − 4.040, −5.127, and − 5.251 kcal/mol, respectively. The MAdCAM-1 had the strongest bond with glycyrrhizin, due to its lowest binding energy. Glycyrrhizin can be a potential drug candidate for cancer treatment. Thus, this protein model can further be validated in laboratory experiments to study its mechanisms of action.

ObjectiveTo study the role of α4β7 integrin for gut homing of monocytes and to explore the biological consequences of therapeutic α4β7 inhibition with regard to intestinal wound healing.DesignWe studied the expression of homing markers on monocyte subsets in the peripheral blood and on macrophage subsets in the gut of patients with IBD and controls with flow cytometry and immunohistochemistry. Integrin function was addressed with dynamic adhesion assays and in vivo gut homing assays. In vivo wound healing was studied in mice deficient for or depleted of α4β7 integrin.ResultsClassical and non-classical monocytes were clearly dichotomous regarding homing marker expression including relevant expression of α4β7 integrin on human and mouse non-classical monocytes but not on classical monocytes. Monocyte-expressed α4β7 integrin was functionally important for dynamic adhesion to mucosal vascular addressin cell adhesion molecule 1 and in vivo gut homing. Impaired α4β7-dependent gut homing was associated with reduced (effect size about 20%) and delayed wound healing and suppressed perilesional presence of wound healing macrophages. Non-classical monocytes in the peripheral blood were increased in patients with IBD under clinical treatment with vedolizumab.ConclusionIn addition to reported effects on lymphocytes, anti-α4β7 therapy in IBD also targets non-classical monocytes. Impaired gut homing of such monocytes might lead to a reduction of wound healing macrophages and could potentially explain increased rates of postoperative complications in vedolizumab-treated patients, which have been observed in some studies.

In a series of studies, using an identical rat intestinal transplantation model, we evaluated the effects of several drugs. FK-506 caused a significant attenuation in the proliferation of allogeneic CD4+ T cells and IFN-γ secreting effector functions. FYT720 resulted in a marked reduction in the numbers of lymphocytes, associated with a reduction of T cell recruitment, in grafts. An anti-MAdCAM antibody was next reported to significantly down-regulate CD4+ T cell infiltration in intestinal grafts by blocking the adhesion molecule, and could be useful as an induction therapy. Concerning TAK-779, this CCR5 and CXCR3 antagonist diminished the number of graft-infiltrating cells by suppressing the expression of their receptors in the graft. As a result, it reduced the total number of recipient T cells involved in graft rejection. As the next step, we focused on the participation of monocytes/ macrophages in this field. PQA-18 has been the focus of a novel immunosuppressant that attenuates not only the production of various cytokines, such as IL-2 & TNF-α, on T cells, but the differentiation of macrophages by inhibiting PAK2 as well. In this report, we summarize our previous studies not only regarding the above drugs, but on an anti-complement drug and a JAK inhibitor as well.

Human gut-associated lymphoid tissues (GALT) play a key role in the acute phase of HIV infection. The propensity of HIV to replicate in these tissues, however, is not fully understood. Access and migration of naive and memory CD4+ T cells to these sites is mediated by interactions between integrin α4β7, expressed on CD4+ T cells, and MAdCAM, expressed on high endothelial venules. We report here that MAdCAM delivers a potent costimulatory signal to naive and memory CD4+ T cells following ligation with α4β7. Such costimulation promotes high levels of HIV replication. An anti-α4β7 mAb that prevents mucosal transmission of SIV blocks MAdCAM signaling through α4β7 and MAdCAM-dependent viral replication. MAdCAM costimulation of memory CD4+ T cells is sufficient to drive cellular proliferation and the upregulation of CCR5, while naive CD4+ T cells require both MAdCAM and retinoic acid to achieve the same response. The pairing of MAdCAM and retinoic acid is unique to the GALT, leading us to propose that HIV replication in these sites is facilitated by MAdCAM-α4β7 interactions. Moreover, complete inhibition of MAdCAM signaling by an anti-α4β7 mAb, an analog of the clinically approved therapeutic vedolizumab, highlights the potential of such agents to control acute HIV infection.

The enhanced recruitment of leukocytes to the inflamed colon is a key feature of ulcerative colitis (UC). The gut-specific adhesion molecules involved in leukocyte recruitment have emerged as recent therapeutic targets. Nicotine absorbed from smoking has been reported to work protectively in UC patients. Our hypothesis is that nicotine may suppress the aberrant leukocyte recruitment and colonic inflammation via the suppression of the overexpressed gut-specific adhesion molecules in the inflamed colon. To test this hypothesis, the severity of colitis and the degree of leukocyte recruitment induced by gut-specific adhesion molecules were assessed in dextran sulfate sodium (DSS) colitis mice (C57BL/6J mice treated with 3% DSS) with or without nicotine treatment. We also studied the in vitro changes in the expression of adhesion molecules by using a vascular endothelial cell line. DSS-induced colitis was accompanied by increases in disease activity index (DAI), histological score, recruitment of leukocytes, and the expression of adhesion molecules, mucosal vascular addressin cell adhesion molecule-1 (MAdCAM-1) and VCAM-1. Nicotine treatment significantly attenuated MAdCAM-1 expression, leukocyte recruitment, DAI, and histological score. The expression of β7-integrin, the ligand for MAdCAM-1, on leukocytes was not affected by nicotine treatment. In vitro study, the TNF-α-enhanced mRNA expression of MAdCAM-1 was reduced by the coadministration of nicotine in a dose-dependent manner, possibly via nicotinic receptor activation. These results supported our hypothesis that nicotine treatment ameliorated colitis through the suppression of MAdCAM-1 expression on the microvessels in the inflamed colon. Further investigation is warranted on the role of nicotine in the treatment of UC. Nicotine ameliorated the over-expressed MAdCAM-1 and inhibited leukocyte recruitment in murine colitis.

CCL25, CXCL10, and Mn2+ induce three distinct active conformations of integrin α4β7, which have selective high affinity for either MAdCAM-1, VCAM-1, or nonselective high affinity for both ligands. Via this mechanism, integrin α4β7 adopts different active conformations to switch its ligand-binding specificity., Chemokine (C-C motif) ligand 25 (CCL25) and C-X-C motif chemokine 10 (CXCL10) induce the ligand-specific activation of integrin α4β7 to mediate the selective adhesion of lymphocytes to mucosal vascular addressin cell adhesion molecule-1 (MAdCAM-1) or vascular cell adhesion molecule-1 (VCAM-1). However, the mechanism underlying the selective binding of different ligands by α4β7 remains obscure. In this study, we demonstrate that CCL25 and CXCL10 induce distinct active conformers of α4β7 with a high affinity for either MAdCAM-1 or VCAM-1. Single-cell force measurements show that CCL25 increases the affinity of α4β7 for MAdCAM-1 but decreases its affinity for VCAM-1, whereas CXCL10 has the opposite effect. Structurally, CCL25 induces a more extended active conformation of α4β7 compared with CXCL10-activated integrin. These two distinct intermediate open α4β7 conformers selectively bind to MAdCAM-1 or VCAM-1 by distinguishing their immunoglobulin domain 2. Notably, Mn2+ fully opens α4β7 with a high affinity for both ligands. Thus, integrin α4β7 adopts different active conformations to switch its ligand-binding specificity.

Integrins are cell surface receptors with bidirectional signalling capabilities that can bind to adhesion molecules in order to mediate homing of leukocytes to peripheral tissues. Gut-selective leukocyte homing is facilitated by interactions between α4β7 and its ligand, mucosal addressin cellular adhesion molecule-1 [MAdCAM-1], while retention of lymphocytes in mucosal tissues is mediated by αEβ7 binding to its ligand E-cadherin. Therapies targeting gut-selective trafficking have shown efficacy in inflammatory bowel disease [IBD], confirming the importance of leukocyte trafficking in disease pathobiology. This review will provide an overview of integrin structure, function and signalling, and highlight the role that these molecules play in leukocyte homing and retention. Anti-integrin therapeutics, including gut-selective antibodies against the β7 integrin subunit [etrolizumab] and the α4β7 integrin heterodimer [vedolizumab and abrilumab], and the non-gut selective anti-α4 integrin [natalizumab], will be discussed, as well as novel targeting approaches using small molecules.

In inflammatory bowel disease (IBD), tumor necrosis factor plays an important role in mediating inflammation, but several other pathways are also involved in eliciting an inflammatory response. One such pathway is the invasion of the intestinal mucosa by leukocytes. Leukocytes within the systemic circulation move to sites of inflammation, and blocking this pathway could be an important treatment strategy for IBD. Anti-integrin therapy blocks the action of integrin on the surface of circulating immune cells and endothelial cell adhesion molecules, thereby inhibiting the interactions between leukocytes and intestinal blood vessels. Natalizumab, which acts on α4-integrin, was the first such drug to be approved for Crohn’s disease, but its use is limited due to the risk of progressive multifocal leukoencephalopathy. Vedolizumab produces few systemic adverse effects because it acts on gut-trophic α4β7 integrin, and has been approved and is being used to treat IBD. Currently, several anti-integrin drugs, including etrolizumab, which acts on β7-integrin, and PF-00547569, which targets mucosal addressin cell adhesion molecule-1, are undergoing clinical trials and the results are being closely watched.

Tissue-resident memory (TRM) CD8 T cells survey a range of non-lymphoid mucosal tissues where they rapidly mediate clearance of viral infections at the entry portals. Vaccines that establish CD8 TRM cells in the cervicovaginal mucosa hold promise for effective immunity against sexually transmitted HIV. We demonstrate that HIV-specific CD8 TRM cells can be established in the murine vaginal mucosa using a combined intranasal and intravaginal mucosal immunization with recombinant influenza-HIV vectors. Using in situ tetramer immunofluorescence microscopy, we found that this mucosally administered prime-boost immunization also resulted in the durable seeding of CD8 T cells in the frontline vaginal epithelial compartment as opposed to the vaginal submucosa. Upon cognate antigen recognition within the vaginal mucosa, these HIV-specific CD8 TRM cells rapidly initiated a tissue-wide state of immunity. The activation of HIV-specific CD8 TRM cells resulted in the upregulation of endothelial vessel addressin expression and substantial recruitment of both adaptive and innate immune cells in the vaginal mucosa. These findings suggest that the epithelial localization of HIV-specific CD8 TRM cell populations and their capacity to rapidly activate both arms of the immune system could significantly augment frontline defenses against vaginal HIV infection.

The treatment of inflammatory bowel disease has evolved with the development of anti-TNF agents. In spite of long-term effectiveness, many patients do not respond or no longer responds to these drugs. Therefore, the development of new drugs that act on different inflammatory pathways has become necessary. Vedolizumab, a gut-specific biological agent, inhibits interaction α4β7 integrin with mucosal addressin cell adhesion molecule-1 without inhibiting systemic immune responses. Long-term vedolizumab therapy in patients with Crohn's disease and ulcerative colitis was safe and effective. Additionally, vedolizumab can be used in patients already failed an anti-TNF therapy. Ustekinumab is a fully human immunoglobulin G1 kappa monoclonal antibody that blocks the p40 subunit of IL-12 and IL-23. Ustekinumab will be a clinically effective agent to use in medically-refractory Crohn's disease especially as a second line drug. Tofacitinib is an oral, small molecule that inhibits JAK1, JAK3 and in a lesser extent, JAK2. Perhaps the most attractive things of these JAK inhibitors is that they are given orally instead of parenterally. Early results showed that patients with moderately to severely active ulcerative colitis receiving tofacitinib were more likely to achieve remission at 8 weeks than those receiving placebo. However, these results have not been as robust in Crohn's disease. Much of the positioning will depend on the safety profile such as opportunistic infection and atherogenic risk. The challenges for the future are to determine the therapeutic drug monitoring-guided dose optimization, optimal timing and drug combinations to produce the most effective, and safest outcomes for IBD patients.

ObjectiveThis phase II, randomised, double-blind, placebo-controlled clinical trial was designed to evaluate the efficacy and safety of PF-00547659, a fully human monoclonal antibody that binds to human mucosal addressin cell adhesion molecule (MAdCAM) to selectively reduce lymphocyte homing to the intestinal tract, in patients with moderate-to-severe Crohn’s disease (CD).DesignEligible adults were aged 18–75 years, with active moderate-to-severe CD (Crohn’s Disease Activity Index (CDAI) 220–450), a history of failure or intolerance to antitumour necrosis factor and/or immunosuppressive agents, high-sensitivity C reactive protein >3.0 mg/L and ulcers on colonoscopy. Patients were randomised to PF-00547659 22.5 mg, 75 mg or 225 mg or placebo. The primary endpoint was CDAI 70-point decrease from baseline (CDAI-70) at week 8 or 12.ResultsIn all, 265 patients were eligible for study entry. Although CDAI-70 response was not significantly different with placebo versus PF-00547659 treatment at weeks 8 or 12, remission rate was greater in patients with higher baseline C reactive protein (>5 mg/L vs >18.8 mg/L, respectively). Soluble MAdCAM decreased significantly from baseline to week 2 in a dose-related manner and remained low during the study in PF-00547659-treated patients. Circulating β7+ CD4+ central memory T-lymphocytes increased at weeks 8 and 12 with PF-00547659 treatment. No safety signal was seen.ConclusionsClinical endpoint differences between PF-00547659 and placebo did not reach statistical significance in patients with moderate-to-severe CD. PF-00547659 was pharmacologically active, as shown by a sustained dose-related decrease in soluble MAdCAM and a dose-related increase in circulating β7+ central memory T cells.Trial registration numberNCT01276509; Results.

Objective To define pharmacodynamic biomarkers in the peripheral blood of patients with Crohn’s disease [CD] after treatment with PF-00547659, an anti-human mucosal addressin cell adhesion molecule-1 [MAdCAM-1] monoclonal antibody. Methods In this Phase 2, randomised, double-blind, controlled study [OPERA], blood samples were analysed from patients with moderate to severe active CD who received placebo or 22.5 mg, 75 mg, or 225 mg of PF-00547659 subcutaneously at baseline and at Weeks 4 and 8, with follow-up at Week 12. Soluble MAdCAM [sMAdCAM] was measured by mass spectrometry, β7-expressing T cells by flow cytometry, and gene transcriptome by RNA sequencing. Results A slight increase in sMAdCAM was measured in the placebo group from baseline to Week 12 [6%], compared with significant decreases in all PF-00547659 groups [–87% to –98%]. A slight increase from baseline to Week 12 was observed in frequency and molecules of equivalent soluble fluorochrome for β7+ central memory T cells in the placebo group [4%], versus statistically significant increases in the active treatment groups [48% to 81%]. Similar trends were seen for β7+ effector memory T cells [placebo, 8%; PF-00547659, 84–138%] and β7+ naïve T cells [8%; 13–50%]. CCR9 gene expression had statistically significant up-regulation [p = 1.09e-06; false discovery rate < 0.1] with PF-00547659 treatment, and was associated with an increase in β7+ T cells. Conclusions Results of the OPERA study demonstrate positive pharmacology and dose-dependent changes in pharmacodynamic biomarker measurements in blood, including changes in cellular composition of lymphocytes and corresponding CCR9 gene expression changes.

Therapy for inflammatory bowel disease (IBD) has changed, with several new agents being evaluated. The era of anti-tumor necrosis factor (anti-TNF) antibody therapy saw remarkable progress in IBD therapy. Some patients, however, do not respond to anti-TNF treatment, or their response decreases over time. This phenomenon highlights the need to identify new molecular targets for therapy in IBD. The targets of new therapeutic molecules in IBD must aim to restore immune dysregulation by the inhibition of proinflammatory cytokines (TNF-α, interleukin [IL]-6, IL-13, IL-17, IL-18, and IL-21) and augmentation of the effect of anti-inflammatory cytokines (IL-10, IL-11, and transforming growth factor β) and to pursue new anti-inflammatory targets, such as regulatory T-cell therapy, Smad7 antisense, Janus-activated kinase inhibition, Toll-like receptor stimulation, leukocyte adhesion, and blockade of T-cell homing via integrins and mucosal addressin cellular adhesion molecule-1. In addition, potential molecular targets could restore mucosal barrier function and stimulate mucosal healing. Despite these potential targets, the value and clinical significance of most new molecules remain unclear, and clinical efficacy and safety must be better defined before their implementation in clinical practice. This article aims to review the promising and emerging molecular targets that could be clinically meaningful for novel therapeutic approaches.

Summary Naive and central memory T lymphocytes (TN and TCM) can infiltrate the inflamed gut mucosa in inflammatory bowel disease (IBD) patients. Homing of these subsets to the gut might be explained by ectopic formation of tertiary lymphoid organs (TLOs), containing high endothelial venules (HEVs). We aimed to evaluate the presence of HEVs and TLOs in inflamed intestinal mucosa of newly diagnosed, untreated IBD patients in relation to the presence of TN and TCM lymphocytes. IBD patients (n = 39) and healthy controls (n = 8) were included prospectively. Biopsy samples of inflamed and normal intestine, respectively, were analysed by immunohistochemistry for lymphocytes (CD3/CD20), blood vessels (CD31) and peripheral lymph node addressin (PNAd) expression (MECA-79). TN and TCM lymphocyte subsets were identified by flow cytometric immunophenotyping. A higher number of HEVs was found in the inflamed colon of patients with ulcerative colitis [median 3·05 HEV/mm2; interquartile range (IQR) = 0–6·39] and ileum of Crohn's disease patients (1·40; 0-4·34) compared to healthy controls (both 0; P = 0·033). A high density of colonic HEVs (HEVhigh) was associated with increased infiltration of TN and TCM in the inflamed gut (median 87%; IQR = 82–93% of T cell population), compared to HEVlow patients (58%; 38–81%; P = 0·003). The number of colonic follicles was higher in HEVhigh patients (median 0·54/mm2; IQR 0·28–0·84) compared to HEVlow patients (0·25/mm2; 0·08–0·45; P = 0·031) and controls (0·31/mm2; 0·23–0·45; P = 0·043). Increased homing of TN and TCM lymphocytes to inflamed gut tissue in IBD patients might be facilitated by ectopic formation of extrafollicular HEVs and TLOs in a subgroup of patients.

The introduction of anti-tumor necrosis factor (anti-TNF) therapies for both Crohn’s disease (CD) and ulcerative colitis (UC) was a landmark in the management of these debilitating diseases. For a substantial proportion of patients, anti-TNF therapies have reduced relapse rates and allowed mucosal healing and, as a result, improved long-term outcomes. However, research into novel therapies for inflammatory bowel diseases (IBD) has been challenging and positive early trials have not always translated to proof of efficacy and safety in late-phase studies. As an alternative to targeting inflammation through cytokines (e.g., TNF), reducing the ability of lymphocytes to generate an inflammatory response is now a therapeutic reality with the availability of the integrin inhibitors. The “gut-selective” vedolizumab is now an established treatment option for UC and CD either before, or after, anti-TNF therapy. Other agents in development that target lymphocyte adhesion include novel anti-integrin and anti-mucosal vascular addressin cell adhesion molecule-1 (anti-MadCAM-1) agents, or target lymphocyte trafficking (e.g. anti-sphingosine 1-phosphate therapies). In addition however, there are novel ways of reducing inflammation by targeting downstream signaling (e.g., Janus kinase inhibitors), the use of antisense oligonucleotides to transforming growth factor-β, or by targeting novel cytokines such as interleukin-12/23 or interleukin-6 that have been implicated in the pathogenesis of IBD. The introduction of a novel formulation of budesonide (budesonide MMX) for UC illustrates that for patients with mild IBD there is also a need for novel therapies and agents in development, include other second-generation corticosteroids that are associated with reduced systemic delivery and approaches to enhance the mucosal barrier or alter the microbiota. Many new and effective therapies are in development for IBD and, if positive in late phase trials, are anticipated to be available within the next decade. Having a number of different agents available will allow the clinician to offer the best therapies for an individual patient. This will likely have huge implications not only for patients and clinicians, but for society as a whole.

Integrins play a crucial role in the development and maintenance of the inflammatory process in patients with inflammatory bowel disease. Vedolizumab is a humanized monoclonal antibody with a predominantly gastrointestinal effect. It specifically inhibits leukocyte integrin α4β7, thus preventing its interaction with mucosal vascular addressin cell adhesion molecule 1(MAdCAM-1), which is involved in the migration of lymphocytes from the blood stream to the intestinal tissue. Vedolizumab is indicated in the treatment of moderate to severe active Crohn's disease and ulcerative colitis in adult patients with poor response, loss of response, or intolerance to conventional treatment or to tumour necrosis factor alpha (TNF-α) antagonists. This review presents the most relevant clinical outcomes of vedolizumab in the treatment of patients with ulcerative colitis.

Integrins play a crucial role in the development and maintenance of the inflammatory process in patients with inflammatory bowel disease. Vedolizumab is a humanized monoclonal antibody with a predominantly gastrointestinal effect. It specifically inhibits leukocyte integrin α4β7, thus preventing its interaction with mucosal vascular addressin cell adhesion molecule 1(MAdCAM-1), which is involved in the migration of lymphocytes from the blood stream to the intestinal tissue. Vedolizumab is indicated in the treatment of moderate to severe active Crohn's disease and ulcerative colitis in adult patients with poor response, loss of response, or intolerance to conventional treatment or to tumour necrosis factor alpha (TNF-α) antagonists. This review presents the most relevant clinical outcomes of vedolizumab in the treatment of patients with ulcerative colitis.