Vascular Addressin Cell Adhesion Molecule Research Articles

Meningeal lymphatic CGRP signaling governs pain via cerebrospinal fluid efflux and neuroinflammation in migraine models.

Recently developed anti-migraine therapeutics targeting calcitonin gene-related peptide (CGRP) signaling are effective, though their sites of activity remain elusive. Notably, the lymphatic vasculature is responsive to CGRP signaling, but whether meningeal lymphatic vessels (MLVs) contribute to migraine pathophysiology is unknown. Mice with lymphatic vasculature deficient in the CGRP receptor (CalcrliLEC mice) treated with nitroglycerin (NTG)-mediated chronic migraine exhibit reduced pain and light avoidance compared to NTG-treated littermate controls. Gene expression profiles of lymphatic endothelial cells (LECs) isolated from the meninges of Rpl22HA/+;Lyve1Cre RiboTag mice treated with NTG revealed increased MLV-immune interactions compared to cells from untreated mice. Interestingly, the relative abundance of mucosal vascular addressin cell adhesion molecule 1 (MAdCAM1)-interacting CD4+ T cells was increased in the deep cervical lymph nodes of NTG-treated control mice but not in NTG-treated CalcrliLEC mice. Treatment of cultured hLECs with CGRP peptide in vitro induced vascular endothelial (VE)-cadherin rearrangement and reduced functional permeability. Likewise, intra cisterna magna injection of CGRP caused rearrangement of VE-Cadherin, decreased MLV uptake of cerebrospinal fluid (CSF), and impaired CSF drainage in control mice, but not in CalcrliLEC mice. Collectively, these findings reveal a previously unrecognized role for lymphatics in chronic migraine, whereby CGRP signaling primes MLVs-immune interactions and reduces CSF efflux.

Gut-associated lymphoid tissue attrition associates with response to anti-α4β7 therapy in ulcerative colitis.

Vedolizumab (VDZ) is a first-line treatment in ulcerative colitis (UC) that targets the α4β7- mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) axis. To determine the mechanisms of action of VDZ, we examined five distinct cohorts of patients with UC. A decrease in naïve B and T cells in the intestines and gut-homing (β7+) plasmablasts in circulation of VDZ-treated patients suggested that VDZ targets gut-associated lymphoid tissue (GALT). Anti-α4β7 blockade in wild-type and photoconvertible (KikGR) mice confirmed a loss of GALT size and cellularity because of impaired cellular entry. In VDZ-treated patients with UC, treatment responders demonstrated reduced intestinal lymphoid aggregate size and follicle organization and a reduction of β7+IgG+ plasmablasts in circulation, as well as IgG+ plasma cells and FcγR-dependent signaling in the intestine. GALT targeting represents a previously unappreciated mechanism of action of α4β7-targeted therapies, with major implications for this therapeutic paradigm in UC.

Dysregulation of CD4+ and CD8+ resident memory T, myeloid, and stromal cells in steroid-experienced, checkpoint inhibitor colitis

BackgroundColitis caused by checkpoint inhibitors (CPI) is frequent and is treated with empiric steroids, but CPI colitis mechanisms in steroid-experienced or refractory disease are unclear.MethodsUsing colon biopsies and blood from...

The Force-Dependent Mechanism of an Integrin α4β7-MAdCAM-1 Interaction.

The interaction between integrin α4β7 and mucosal vascular addressin cell-adhesion molecule-1 (MAdCAM-1) facilitates the adhesion of circulating lymphocytes to the surface of high endothelial venules in inflammatory bowel diseases (IBDs). Lymphocyte adhesion is a multistep cascade involving the tethering, rolling, stable adhesion, crawling, and migration of cells, with integrin α4β7 being involved in rolling and stable adhesions. Targeting the integrin α4β7-MAdCAM-1 interaction may help decrease inflammation in IBDs. This interaction is regulated by force; however, the underlying mechanism remains unknown. Here, we investigate this mechanism using a parallel plate flow chamber and atomic force microscopy. The results reveal an initial increase in the lifetime of the integrin α4β7-MAdCAM-1 interaction followed by a decrease with an increasing force. This was manifested in a two-state curve regulated via a catch-bond-slip-bond conversion regardless of Ca2+ and/or Mg2+ availability. In contrast, the mean rolling velocity of cells initially decreased and then increased with the increasing force, indicating the flow-enhanced adhesion. Longer tether lifetimes of single bonds and lower rolling velocities mediated by multiple bonds were observed in the presence of Mg2+ rather than Ca2+. Similar results were obtained when examining the adhesion to substrates co-coated with chemokine CC motif ligand 25 and MAdCAM-1, as opposed to substrates coated with MAdCAM-1 alone. In conclusion, the integrin α4β7-MAdCAM-1 interaction occurs via ion- and cytokine-dependent flow-enhanced adhesion processes and is regulated via a catch-bond mechanism.

Gut-licensed β7+ CD4+ T cells contribute to progressive retinal ganglion cell damage in glaucoma.

Glaucoma is the leading cause of irreversible blindness. Currently, most therapeutic strategies aim to reduce elevated intraocular pressure (EIOP), but this does not always halt disease progression. Evidence suggests a role for T cells in glaucoma pathogenesis, but the underlying mechanisms remain largely unknown. Here, we found that the percentage of circulating CD4+ T cells expressing a gut-homing integrin β7 was increased in patients with glaucoma and was associated with disease stage. In an EIOP-triggered glaucoma mouse model, β7+ CD4+ T cells infiltrated the retina in the progressive phase of glaucoma via eliciting retinal endothelial cell expression of mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1). MAdCAM-1 was minimally detected in retinas of healthy mice, and neutralization with an MAdCAM-1 antibody ameliorated retinal ganglion cell (RGC) loss and glial activity in mice with glaucoma. We furthermore found that EIOP-induced β7+ CD4+ T cells homed to the gut during the acute phase of glaucoma, which was essential for progressive RGC damage in diseased mice. Gut-homing β7+ CD4+ T cells underwent transcriptional reprogramming, showing up-regulated pathways enriched in autoimmune diseases, bacteria responses, mucosal immunity, and glial activity. Gut-homing β7+ CD4+ T cells gained the competence to induce retinal MAdCAM-1 expression and to cross the blood-retina barrier. Together, our study reveals a role of gut-licensed β7+ CD4+ T cells and MAdCAM-1 in RGC degeneration and emphasizes the importance of the "gut-retina" axis in glaucoma.

Elevated Systemic Levels of Markers Reflecting Intestinal Barrier Dysfunction and Inflammasome Activation Are Correlated in Severe Mental Illness.

Gut microbiota alterations have been reported in severe mental illness (SMI) but fewer studies have probed for signs of gut barrier disruption and inflammation. We hypothesized that gut leakage of microbial products due to intestinal inflammation could contribute to systemic inflammasome activation in SMI. We measured plasma levels of the chemokine CCL25 and soluble mucosal vascular addressin cell adhesion molecule-1 (sMAdCAM-1) as markers of T cell homing, adhesion and inflammation in the gut, lipopolysaccharide binding protein (LBP) and intestinal fatty acid binding protein (I-FABP) as markers of bacterial translocation and gut barrier dysfunction, in a large SMI cohort (n = 567) including schizophrenia (SCZ, n = 389) and affective disorder (AFF, n = 178), relative to healthy controls (HC, n = 418). We assessed associations with plasma IL-18 and IL-18BPa and leukocyte mRNA expression of NLRP3 and NLRC4 as markers of inflammasome activation. Our main findings were: (1) higher levels of sMAdCAM-1 (P = .002), I-FABP (P = 7.6E-11), CCL25 (P = 9.6E-05) and LBP (P = 2.6E-04) in SMI compared to HC in age, sex, BMI, CRP and freezer storage time adjusted analysis; (2) the highest levels of sMAdCAM-1 and CCL25 (both P = 2.6E-04) were observed in SCZ and I-FABP (P = 2.5E-10) and LBP (3) in AFF; and (3), I-FABP correlated with IL-18BPa levels and LBP correlated with NLRC4. Our findings support that intestinal barrier inflammation and dysfunction in SMI could contribute to systemic inflammation through inflammasome activation.

A genomic address code directs assembly and function of NKX2‐3:COUP‐TFII complexes that drive organotypic expression of the mucosal vascular addressin

The mucosal vascular addressin cell-adhesion molecule 1 (MAdCAM1) is selectively displayed by intestinal postcapillary and high endothelial venule sites of immune cell recruitment from the blood. It serves as a gatekeeper for lymphocyte entry and is a therapeutic target for inflammatory bowel disease, yet the molecular mechanisms underlying its targeted expression remain unclear. We describe a phylogenetically conserved genomic element within the Madcam1 promoter that integrates intestinal (homeodomain protein Nkx2-3), capillary/arterial (repressive effector proteins of the Notch signaling pathway), and venule-selective (COUP-TFII) transcription regulatory mechanisms with inflammatory (NfkB-dependent) signals to direct MAdCAM1 expression. The regulatory motif cooperatively binds Nkx2-3 and COUP-TFII to activate transcription from the Madcam1 promoter. Heterodimer formation is DNA dependent and is mediated by the Nkx2-3 tinman domain. The Notch downstream repressor Hey1 competes for binding of NKX2-3, and Notch signaling and Hey1 overexpression suppress promoter activity and Madcam1 induction in endothelial cells. Pan-endothelial overexpression of COUP-TFII counters Hey1 repression and drives ectopic MAdCAM1 in Nkx2-3+ intestinal capillaries. The results define a genomic address code for MAdCAM1 expression and control of lymphocyte homing via intestinal venules. Finally, we identify similar composite elements in genes involved in cardiovascular and neuronal development, suggesting a mechanism for combinatorial regulation of organogenesis by COUP-TFII and NXK2 family members.

A195 A RARE CAUSE OF SEVERE REFRACTORY DIARRHEA IN A PATIENT WITH COMMON VARIABLE IMMUNE DEFICIENCY ASSOCIATED INTESTINAL ENTEROPATHY

Abstract Background CVID is the most common type of severe antibody deficiency. Gastrointestinal manifestations affect approximately 20–50% of patients. Boland et al. described in a case series that 2/3 CVID patients were able to achieve clinical and endoscopic remission with Vedolizumab. This α4β7 integrin antagonist inhibits intestinal T cell translocation by blocking integrin interactions with mucosal vascular addressin cell adhesion molecule 1, reducing lymphocyte mediated inflammation. However, despite its novel use for this indication, limited data is available on the consequences of this therapy in patients with CVID. Aims To report on a case assessing the efficacy and outcomes of Vedolizumab for the treatment of CVID associated autoimmune enteropathy. Methods We present the case of a 50-year-old male presenting with severe refractory diarrhea and malnutrition. A colonoscopy demonstrated patchy ulceration and biopsies revealed ulcerated active colitis, negative for CMV. He was treated with Vedolizumab and Total Parental Nutrition (TPN). His diarrhea resolved, he gained 20 kg and he was weaned off TPN. In 2019, he re-presented with severe diarrhea. Subsequently endoscopic evaluation revealed patchy edematous colonic mucosa and biopsies demonstrated minimally active colitis, negative for CMV. He again responded to Vedolizumab re-induction, however shortly after, his diarrhea returned aggressively. CT enterography demonstrated active jejunal inflammation. Subsequently, an EGD revealed multiple duodenal ulcers and luminal narrowing. Biopsies of the small bowel were sent to histopathology. Results CMV superinfection was diagnosed on pathology (image 1). This patient’s diarrhea completely resolved with IV Gancyclovir and he was discharged on maintenance treatment with oral Valganciclovir. Conclusions This represents the first reported case of CMV enteritis secondary to Vedolizumab for the treatment of CVID associated autoimmune enteropathy. In this case, clinical and endoscopic remission was observed with Vedolizumab, however subsequently hampered by CMV reactivation. Hommel et al., published a positive correlation in a single centre retrospective cohort study of CMV reactivation in patients with ulcerative colitis treated with Vedolizumab. A large retrospective review of data from a multicenter consortium database of over 1000 Vedolizumab treated IBD patients reported CMV colitis in only 4 patients. CMV reactivation appears to be an exceptionally rare but important event in patients treated with Vedolizumab. Based on this report, patients with CVID associated enteropathy and refractory diarrhea should be carefully screened for CMV when treated with Vedolizumab. Further prospective data assessing the incidence of CMV reactivation in patients with Vedolizumab therapy is required to further define these findings. Funding Agencies None

A200 VEDOLIZUMAB IS AN EFFECTIVE TREATMENT OPTION FOR NON INFLAMMATORY BOWEL DISEASE RELATED ENTEROPATHY

Abstract Background Vedolizumab is an α4β7 integrin antagonist which inhibits intestinal T-cell translocation by blocking integrin interactions with mucosal vascular addressin cell adhesion molecule 1, reducing lymphocyte mediated inflammation. Its gut selective mode of action and safety profile have lead to reports of off-label use of vedolizumab for non-IBD related inflammatory intestinal disorders. Aims 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. Methods EMBASE, Medline, Clinicaltrials.gov and Cochrane CENTRAL were searched on September 12, 2019 for case studies, case series and cohort studies without language restriction yielding 356 studies with 164 duplicates, 74 non-applicable studies, leaving 118 studies. After full text review, 98 studies were excluded, leaving 20 included studies. Results 65% of patients (51/79) achieved clinical response. 40.5% (15/37) of patients experienced endoscopic improvement and 33% (17/51) of patients experienced histologic improvement. The duration of treatment varied from patients receiving only induction doses to up to 70 months for maintenance therapy. There were four reported cases of withdrawal due to adverse events from Vedolizumab. Conclusions In a treatment refractory population, over 60% of patients reported to have a clinical response and one-third endoscopic/histologic response, indicating that Vedolizumab is a viable option for patients with refractory non-IBD enteropathy. Funding Agencies None

Probiotics, Anticipation Stress, and the Acute Immune Response to Night Shift.

IntroductionSleep disturbance and sleep disruption are associated with chronic, low grade inflammation and may underpin a range of chronic diseases in night shift workers. Through modulation of the intestinal microbiota, probiotic supplements may moderate the effects of sleep disruption on the immune system. The aim of this study was to examine 14 days of daily probiotic supplementation on the acute response of acute phase proteins and immune markers to sleep disruption associated with night shift work (Australia and New Zealand Clinical Trials Registry: 12617001552370).MethodsIndividuals (mean age 41 ± 11 yrs; 74% female) performing routine night shift were randomly assigned to a probiotic group (1 × 1010 colony forming units (CFU) Lactobacillus acidophilus DDS-1 or 1 × 1010 CFU Bifidobacterium animalis subsp. lactis UABla-12) or placebo (n= 29 per group). Participants undertook a 14-day supplementation period that coincided with a period of no night shifts followed by two consecutive night shifts. Blood samples were collected prior to the start of supplementation (V1), prior to commencing the first night shift (V2), after the first night shift (V3) and after the second night shift (V4). Serum was assessed for markers of stress (cortisol), acute phase response (C reactive protein (CRP), erythrocyte sedimentation rate, pentraxin), adhesion markers (serum E-selectin, mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1), and serum cytokines (interleukin (IL)-1ra, IL-1β, IL-6, tumor necrosis factor (TNF)-α, IL-10). Sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI) and a Fitbit activity tracker.ResultsThe groups were well balanced on key markers and the probiotic strains were well tolerated. The 14-day supplementation period that coincided with typical night-day sleep-wake cycles leading up to night shift (V1 to V2) was associated with significant changes in the placebo group in the concentration of serum cortisol (p = 0.01), pentraxin (p = 0.001), MAdCAM-1 (p = 0.001), and IL-1ra (p=0.03). In contrast, probiotic supplementation moderated changes in these serum markers from V1 to V2. No significant interaction effects (time by group) were observed for the serum markers prior to and after night shift work following probiotic supplementation due to the substantial changes in the serum markers that occurred during the normal sleep period from V1 to V2.ConclusionsProbiotics may moderate the effects of anticipatory stress on the immune system in the lead up to night shift.

Mucin-Like Domain of Mucosal Addressin Cell Adhesion Molecule-1 Facilitates Integrin α4β7-Mediated Cell Adhesion Through Electrostatic Repulsion.

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.

Recent advances in inflammatory bowel disease therapy

Inflammatory bowel disease (IBD) is a group of chronic, relapsing disorders of the gastrointestinal (GI) tract that significantly affect patient's quality of life. The main goals of IBD treatment are long-lasting clinical remission without serious adverse events. The lack of fully effective treatment urges researchers to seek for new therapeutic strategies and design of novel anti-inflammatory compounds.In this review, we focus on the latest advances in the IBD therapy. We characterize the clinical efficacy and mechanism of action of stem cell-, antibody- and small molecule-based methods of treatment that already reached clinic or are currently evaluated in clinical studies. The scope of this article is on agents targeting interleukin 12 and 23, integrins α4β7 and αEβ7, mucosal vascular addressin cell adhesion molecule, janus kinases, sphingosine-1-phosphate and toll-like receptor 9. We also describe recent advances in the discovery of biomarkers in IBD.

Machine learning algorithms reveal unique gene expression profiles in muscle biopsies from patients with different types of myositis

ObjectivesMyositis is a heterogeneous family of diseases that includes dermatomyositis (DM), antisynthetase syndrome (AS), immune-mediated necrotising myopathy (IMNM), inclusion body myositis (IBM), polymyositis and overlap myositis. Additional subtypes of myositis...

Baseline levels of dynamic CD4+ T cell adhesion to MAdCAM-1 correlate with clinical response to vedolizumab treatment in ulcerative colitis: a cohort study

BackgroundWhile the number of therapeutic options for treating inflammatory bowel diseases (IBD) is increasing, evidence for rational treatment decisions is scarce in many cases. In particular, appropriate biomarkers to predict the response to the anti-α4β7 integrin antibody vedolizumab are currently lacking.MethodsWe performed a cohort study with 21 patients suffering from ulcerative colitis (UC), in which first-time treatment with vedolizumab was initiated. CD4+ T cells were isolated from the peripheral blood and dynamic adhesion to recombinant mucosal vascular addressin cell adhesion molecule (MAdCAM-)1 in vitro as well as the effect of vedolizumab on such adhesion in vitro was determined. The expression of α4β1 integrin on peripheral blood CD4+ T cells was quantified by flow cytometry. Electronic patient records were reviewed to determine clinical response to vedolizumab.ResultsDynamic adhesion of peripheral blood CD4+ T cells to MAdCAM-1 and the reduction of adhesion following vedolizumab treatment in vitro were higher and the change in α4β1 expression on CD4+ T cells was different in vedolizumab responders and non-responders. Responders could be identified with high specificity and positive-predictive value.ConclusionsDetermining dynamic adhesion of CD4+ T cells to MAdCAM-1 and the in vitro response to vedolizumab before treatment initiation or dynamic integrin regulation in the early course of treatment seem to be promising tools to predict the clinical response to vedolizumab therapy. Larger prospective studies are warranted.

Bile Acids Modulate Colonic MAdCAM‐1 Expression in a Murine Model of PSC‐IBD

Background & ObjectivePrimary Sclerosing Cholangitis (PSC) is a progressive cholestatic liver disease of unknown etiology that carries a strong association with inflammatory bowel disease (IBD). PSC‐associated IBD (PSC‐IBD) displays a unique colitis phenotype characterized by right side predominant inflammation and increased risk of colorectal cancer compared to non‐PSC‐IBD. Although the initiation/progression PSC‐IBD remains unclear, some evidence supports an integral role for the gut‐specific mucosal vascular addressin cell adhesion molecule (MAdCAM‐1) in modulating both hepatic and intestinal inflammation. Multidrug resistance protein 2 (Mdr2) knockout mice develop spontaneous cholestatic liver injury and fibrosis mirroring human PSC. To further elucidate disease mechanisms of PSC‐IBD, we combined Mdr2−/− mice with the chemically inducible model of DSS colitis (Mdr2−/−/DSS). We hypothesize that alterations in bile acids promote mucosal inflammation in this murine model of combined cholestasis/colitis. There are currently no good models for PSC‐IBD, so our objective is to develop a murine model mimicking PSC‐IBD for studying the gut‐liver axis and proinflammatory crosstalk.Methods & ResultsMice were fed 1.5% DSS for 5 days and recovered for 4 days before being euthanized. Transformed sinusoidal endothelial cells (TSECs) were treated with 5 ng/ml of TNF‐αand/or 100μM of ursodeoxycholic acid (UDCA). UDCA treated mice were fed 0.5% UDCA fortified chow for 2 weeks and throughout the previously described DSS course.In this model, Mdr2−/− mice displayed marked alterations in intestinal bile acid composition and increased susceptibility to DSS colitis based on weight loss, disease activity index, histology, and inflammatory cytokines, etc. Mdr2−/− mice also displayed an upregulation of colonic MAdCAM‐1 expression as compared to C57BL/6 colitis controls. In vitro work utilizing transformed sinusoidal endothelial cells (TSECs) and bEnd.3 cells (brain endothelial cells) revealed that MAdCAM‐1 was potently induced by TNF‐α and that this induction was significantly attenuated by co‐treatment with ursodeoxycholic acid (UDCA). In vivo, DSS‐treated Mdr2−/− mice fed with UCDA fortified chow demonstrated significant attenuation of colitis susceptibility and decreased colonic MAdCAM‐1 expression as compared to standard chow controls.ConclusionsThese findings suggest a unique interplay between alterations in bile acid homeostasis and intestinal MAdCAM‐1 expression in modulating pro‐inflammatory cross‐talk along the gut‐liver axis and identify intestinal bile acid signaling as a potential therapeutic target for the treatment of PSC‐IBD.Support or Funding InformationUniversity of Colorado GI and Liver Innate Immune Program (GALIIP)

Challenges and opportunities for IBD drug development: from early stage to regulatory approval

Increased understanding of the immunopathology of inflammatory bowel disease (IBD) has resulted in the development of novel therapies such as vedolizumab or ustekinumab, and the investigation of new agents including...

Vedolizumab-mediated integrin α4β7 blockade does not control HIV-1SF162 rebound after combination antiretroviral therapy interruption in humanized mice.

The combined combination antiretroviral therapy (cART) and anti-α4β7 RM-Act-1 antibody therapy allows macaques to durably control simian immunodeficiency virus (SIV) rebound after withdrawal of the interventions. Here, we aimed to investigate whether vedolizumab (VDZ), a clinical-grade humanized anti-α4β7 antibody, would have similar effects in controlling live HIV-1 infection in humanized mice. The integrin α4β7 blockade by VDZ was evaluated on human primary memory CD4+ T (MEMT) cells and retinoic acid-induced gut-homing α4β7+MEMT cells (α4β7+MEMT) in vitro. The antiretroviral activity of VDZ was determined using pseudotyped R5-tropic HIV-1SF162, which displays binding activity to α4β7. The preventive and immunotherapeutic efficacies of VDZ were further investigated in humanized mice using the live HIV-1SF162 strain compared with RM-Act-1. VDZ effectively and dose-dependently blocked the binding of mucosal vascular addressin cell adhesion molecule-1 (MAdCAM-1), the native ligand of α4β7, to α4β7+MEMT cells. HIV-1SF162 not only displayed binding capacity to α4β7-expressing cells, but also showed an increased infectivity in retinoic acid-induced α4β7+MEMT cells pretreated with VDZ. Moreover, VDZ failed to prevent live HIV-1SF162 infection and did not reduce the peak viral load when administrated prior to viral challenge in humanized mice. Lastly, in immunotherapeutic settings, the withdrawal of combined cART with either VDZ or RM-Act-1 resulted in an uncontrolled HIV-1SF162 rebound in humanized mice, whereas the α4β7 molecules remained significantly blocked on circulating CD4+ T cells. VDZ neither prevents nor controls HIV-1SF162 infection both in vitro and in humanized mice. Our findings have significant implications to the clinical application of VDZ in HIV-1 preventive and immunotherapeutic interventions.

Gut microbiota-dependent CCR9+CD4+ T cells are altered in secondary progressive multiple sclerosis.

The mechanism underlying the progression of relapsing-remitting multiple sclerosis to secondary progressive multiple sclerosis (SPMS), characterized by accumulating fixed disability, is yet to be fully understood. Although alterations in the gut microbiota have recently been highlighted in multiple sclerosis pathogenesis, the mechanism linking the altered gut environment with the remote CNS pathology remains unclear. Here, we analyse human CD4+ memory T cells expressing the gut-homing chemokine receptor CCR9 and found a reduced frequency of CCR9+ memory T cells in the peripheral blood of patients with SPMS relative to healthy controls. The reduction in the proportion of CCR9+ cells among CD4+ memory T cells (%CCR9) in SPMS did not correlate with age, disease duration or expanded disability status scale score, although %CCR9 decreased linearly with age in healthy controls. During the clinical relapse of both, relapsing-remitting multiple sclerosis and neuromyelitis optica, a high proportion of cells expressing the lymphocyte activating 3 gene (LAG3) was detected among CCR9+ memory T cells isolated from the CSF, similar to that observed for mouse regulatory intraepithelial lymphocytes. In healthy individuals, CCR9+ memory T cells expressed higher levels of CCR6, a CNS-homing chemokine receptor, and exhibited a regulatory profile characterized by both the expression of C-MAF and the production of IL-4 and IL-10. However, in CCR9+ memory T cells, the expression of RORγt was specifically upregulated, and the production of IL-17A and IFNγ was high in patients with SPMS, indicating a loss of regulatory function. The evaluation of other cytokines supported the finding that CCR9+ memory T cells acquire a more inflammatory profile in SPMS, reporting similar aspects to CCR9+ memory T cells of the elderly healthy controls. CCR9+ memory T cell frequency decreased in germ-free mice, whereas antibiotic treatment increased their number in specific pathogen-free conditions. Here, we also demonstrate that CCR9+ memory T cells preferentially infiltrate into the inflamed CNS resulting from the initial phase and that they express LAG3 in the late phase in the experimental autoimmune encephalomyelitis mouse model of multiple sclerosis. Antibiotic treatment reduced experimental autoimmune encephalomyelitis symptoms and was accompanied by an increase in CCR9+ memory T cells in the peripheral blood. Antibodies against mucosal vascular addressin cell adhesion molecule 1 (MADCAM1), which is capable of blocking cell migration to the gut, also ameliorated experimental autoimmune encephalomyelitis. Overall, we postulate that the alterations in CCR9+ memory T cells observed, caused by either the gut microbiota changes or ageing, may lead to the development of SPMS.

Outcome of Pregnancies in Female Patients With Inflammatory Bowel Diseases Treated With Vedolizumab.

Vedolizumab is an IgG1 anti-α4β7 integrin antibody approved for the treatment of inflammatory bowel diseases [IBD], but without clear safety data during conception, pregnancy and nursing. Animal studies showed that mucosal vascular addressin cell adhesion molecule 1 [MAdCAM-1] is expressed by maternal vessels in the placenta and recruits α4β7-expressing cells that are considered important for maternal/fetal tolerance. Blocking this interaction by vedolizumab might affect this process. We aimed to evaluate pregnancy outcomes in vedolizumab-treated female IBD patients. We conducted a retrospective, multicentre Belgian observational study. Details on disease activity, prenatal complications, delivery and neonatal outcome were collected through a case report form. Twenty-four pregnancies were reported. Five women had active disease at conception and one patient flared during pregnancy. There were 23 live births. Complications were observed in 25% of pregnancies [premature rupture of membranes, pre-eclampsia, miscarriage, elective termination and stillbirth] and in 35% of infants [prematurity, intra-uterine growth retardation, small for gestational age and congenital malformations including hip dysplasia, pulmonary valve stenosis and Hirschprung's disease]. Vedolizumab was continued throughout pregnancy in two females and stopped in the 1st and 2nd trimester in five and 16 patients, respectively. For live born children, the median [interquartile range] gestational age, weight and Apgar score 5 min after birth were 39 [37-39.6] weeks, 3270 [3080-3585] grams and 10 [9-10], respectively. Although several complications were observed, both in mothers and in newborns, no firm conclusions can be drawn. Awaiting prospective and controlled registries, vigilance and strict follow-up of pregnant patients treated with vedolizumab seems mandatory.

Endothelial Microvesicles and Soluble Markers of Endothelial Injury in Critically Ill Newborns.

Neonatal systemic inflammatory response and multiple organ dysfunction syndrome are the main postnatal insults influencing mortality and morbidity. Critically ill newborns with high predicted mortality are supported by extracorporeal membrane oxygenation (ECMO). Biomarkers of inflammatory response and endothelial injury can be used for early diagnosis and treatment of critical neonatal situations. The aim of our study was to explore plasma proteins and endothelial microvesicles as markers of inflammation and endothelial activation in newborns on ECMO and to compare them with healthy neonates. Thirteen newborns on ECMO and 13 healthy newborns were included in the study. Plasma soluble biomarkers were measured using multiplex immunoassay based on Luminex® xMAP multianalyte profiling platform. The total microvesicle count and plasma level of surface antigen-specific microvesicles were determined by flow cytometry. The plasma concentration of cell-derived microvesicles was measured using annexin-V labeling, and the endothelial origin of microvesicles was determined using lineage-specific antigen labeling of endothelial cell/microvesicle markers (endoglin/CD105, PECAM1/CD31, VEGFR2/CD309, and MadCAM1). Inflammatory markers (procalcitonin, IL-1β, IL-6, and IL-22) were increased in the ECMO group (P < 0.01). The assessment of endothelial markers showed higher concentrations of endocan and angiopoietin-2 (P < 0.01) in the ECMO group while VEGF in the ECMO group was significantly lower (P < 0.01). In the ECMO group, the concentration of annexin-V-positive microvesicles (total microvesicles) and endothelial microvesicles expressing mucosal vascular addressin cell adhesion molecule 1 (MadCAM1) was increased (P = 0.05). In summary, we found increased concentrations of soluble inflammatory and endothelial markers in the plasma of critically ill newborns with multiple organ dysfunction. Increased plasma concentrations of microvesicles may reflect the activation or damage of blood cells and vasculature including endothelial cells. The measurement of cell membrane-derived microvesicles may be added to the panel of established inflammatory markers in order to increase the sensitivity and specificity of the diagnostic process in critically ill newborns.