Cholinergic Anti-inflammatory Pathway Attenuates Acute Liver Failure Through Inhibiting MAdCAM1/α4ß7-mediated Gut-derived Proinflammatory Lymphocytes Accumulation.

BACKGROUND & AIMS: The function of cholinergic anti-inflammatory pathway (CAP) in acute liver failure (ALF) with inflammatory storm remains indefinite. The liver-gut axis has been proved to be crucial for liver homeostasis. Investigation about CAP regulation on liver-gut axis would enrich our understanding over cholinergic anti-inflammatory mechanism. METHODS: Co-injection of lipopolysaccharide and D-galactosamine was used to establish the model of ALF. PNU-282987 was used to activate the CAP. Histological staining, real-time polymerase chain reaction, Western blotting, RNA sequencing, and flow cytometry were conducted. Liver biopsy specimens and patients' serum from patients with liver failure were also analyzed. RESULTS: We confirmed that activating the CAP alleviated hepatocyte destruction, accompanied by a significant decrease in hepatocyte apoptosis, pro-inflammatory cytokines, and NLRP3 inflammasome activation. Moreover, hepatic MAdCAM1 and serum MAdCAM1 levels were induced in ALF, and MAdCAM1 levels were positively correlated with the extent of liver damage and the expression of pro-inflammatory markers. Furthermore, activating the CAP mainly downregulated ectopic expression of MAdCAM1 on endothelial cells, and inhibition of NF-κB p65 nuclear translocation was partly attributed to the decreased MAdCAM1. Notably, in ALF, the aberrant hepatic expression of MAdCAM1 subsequently recruited gut-derived α4ß7+ CD4+T cells to the liver, which exhibited an augmented IFN-γ-secreting and IL-17-producing phenotype. Finally, we revealed that the levels of serum and hepatic MAdCAM1 were elevated in patients with liver failure and closely correlated with clinical course. Increasing hepatic infiltration of ß7+ cells were also confirmed in patients. CONCLUSIONS: Activating the CAP attenuated liver injury by inhibiting MAdCAM1/α4ß7 -mediated gut-derived proinflammatory lymphocytes infiltration, which provides a potential therapeutic target for ALF.

Mucosal Addressin Cell Adhesion Molecule 1 Expression Reflects Mucosal Inflammation and Subsequent Relapse in Patients with Ulcerative Colitis.

BACKGROUND AND AIMS: Mucosal addressin cell adhesion molecule 1 [MAdCAM-1] is upregulated in the vascular endothelium of the colonic mucosa in ulcerative colitis [UC]. Although the association between MAdCAM-1 expression and mucosal inflammation has been discussed, the association with the clinical course of UC patients has not been reported. In this study we investigated not only the association between mucosal MAdCAM-1 expression and mucosal inflammation, but also its association with subsequent relapse in UC patients with clinical remission. METHODS: Eighty UC patients in remission who visited Kyoto Prefectural University of Medicine for follow-up for 2 years were included. Biopsy samples were collected during colonoscopy, and transcriptional expression levels of UC-related cytokines and MAdCAM-1 were quantified using real-time polymerase chain reaction. MAdCAM-1 mRNA expression and protein expression by immunohistochemistry were compared in patients who subsequently relapsed and those who remained in remission and were examined in relation to endoscopic findings, histological activity and cytokine expression. RESULTS: MAdCAM-1 expression was correlated with endoscopic severity, and significantly elevated in histologically active mucosa than inactive mucosa. Furthermore, MAdCAM-1 expression levels were closely correlated with those of several cytokines. MAdCAM-1 mRNA and protein expression were significantly higher in the relapse group than in the remission group, indicating that MAdCAM-1 expression in the mucosa is already elevated in UC patients in clinical remission who subsequently relapse. CONCLUSIONS: MAdCAM-1 expression in the colonic mucosa of UC patients is related to mucosal inflammation and subsequent relapse; it may serve as a marker for both relapse and therapeutic effectiveness in UC.

Dach1 transcription factor regulates the expression of peripheral node addressin and lymphocyte trafficking in lymph nodes.

Lymphocytes regulate the immune response by circulating between the vascular and lymphatic systems. High endothelial venules, HEVs, special blood vessels expressing selective adhesion molecules, such as PNAd and MAdCAM-1, mediate naïve lymphocyte migration from the vasculature into the lymph nodes and Peyer's patches. We have identified that DACH1 is abundantly expressed in developing HEV-type endothelial cells. DACH1 showed a restricted expression pattern in lymph node blood vessels during the late fetal and early neonatal periods, corresponding to HEV development. The proportion of MAdCAM-1+ and CD34+ endothelial cells is reduced in the lymph nodes of neonatal conventional and vascular-specific Dach1-deficient mice. Dach1-deficient lymph nodes in adult mice demonstrated a lower proportion of PNAd+ cells and lower recruitment of intravenously administered lymphocytes from GFP transgenic mice. These findings suggest that DACH1 promotes the expression of HEV-selective adhesion molecules and mediates lymphocyte trafficking across HEVs into lymph nodes.

Long-Term Safety and Efficacy of the Anti-Mucosal Addressin Cell Adhesion Molecule-1 Monoclonal Antibody Ontamalimab (SHP647) for the Treatment of Crohn's Disease: The OPERA II Study.

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.

Circulating MAdCAM-1 and ITGB7 in Patients with Plaque Psoriasis and Eruptive Lichen Planus-Preliminary Data.

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, α4ß7 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 > 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.

Irisin supports integrin-mediated cell adhesion of lymphocytes.

Irisin, a myokine released from skeletal muscle, has recently been found to act as a ligand for the integrins αVß5, αVß1, and α5ß1 expressed on mesenchymal cells, thereby playing an important role in the metabolic remodeling of the bone, skeletal muscle and adipose tissues. Although the immune-modulatory effects of irisin in chronic inflammation have been documented, its interactions with lymphocytic integrins have yet to be elucidated. Here, we show that irisin supports the cell adhesion of human and mouse lymphocytes. Cell adhesion assays using a panel of inhibitory antibodies to integrins have shown that irisin-mediated lymphocyte adhesion involves multiple integrins including not only α4ß1 and α5ß1, but also leukocyte-specific αLß2 and α4ß7. Importantly, mouse lymphocytic TK-1 cells that lack the expression of ß1 integrins have exhibited αLß2- and α4ß7-mediated cell adhesion to irisin. Irisin has also been demonstrated to bind to purified recombinant integrin αLß2 and α4ß7 proteins. Thus, irisin represents a novel ligand for integrin αLß2 and α4ß7, capable of supporting lymphocyte cell adhesion independently of ß1 integrins. These results suggest that irisin may play an important role in regulating lymphocyte adhesion and migration in the inflamed vasculature.

Defining High Endothelial Venules and Tertiary Lymphoid Structures in Cancer.

High endothelial venules (HEVs) are structurally distinct blood vessels that develop during embryonic and neonatal life in all secondary lymphoid organs except the spleen. HEVs are critical for initiating and maintaining immune responses because they extract naïve and memory lymphocytes from the bloodstream, regardless of antigen receptor specificity, and deliver them to antigen-presenting cells inside lymph nodes under homeostatic conditions. HEVs also develop postnatally in nonlymphoid organs during chronic inflammation driven by autoimmunity, infection, allografts, and cancer. Extranodal HEVs are usually surrounded by dense lymphocytic infiltrates organized into lymph-node like, T- and B-cell-rich areas called tertiary lymphoid structures (TLS). HEV neogenesis is thought to facilitate the generation of tissue-destroying lymphocytes inside chronically inflamed tissues and cancers.We are studying the mechanisms underpinning HEV neogenesis in solid cancers and the role of homeostatic T-cell trafficking in controlling cancer immunity. In this chapter we describe methods for identifying HEV in tissue sections of cancerous tissues in humans and mice using immunohistochemical staining for the HEV-specific marker peripheral lymph node addressin (PNAd). L-selectin binding to PNAd is a necessary first step in homeostatic lymphocyte trafficking which is the defining function of HEV. We also describe methods to measure L-selectin-dependent homing of lymphocytes from the bloodstream into lymphoid tissues and tumors in preclinical cancer models.

Vedolizumab for the treatment of moderately to severely active ulcerative colitis.

Ulcerative colitis is a chronic, idiopathic, inflammatory bowel disease characterized by a relapsing and remitting course. A substantial proportion of patients fail conventional therapies despite therapy with immunosuppressives and tumor necrosis factor antagonists. Accordingly, newer therapeutic agents that target disease-specific inflammation and minimize adverse events are required. Central to the pathogenesis of ulcerative colitis is an aberrant host response to commensal microorganisms with a resultant dysregulation of gut immune homeostasis and lymphocyte trafficking. Recently, a newer biologic, vedolizumab, which blocks lymphocyte trafficking, has been developed for use in moderate to severe ulcerative colitis. The efficacy of this agent has been demonstrated to be similar to that of other currently available biologics, and the selectivity of this agent in blocking lymphocyte migration to the gut has substantially reduced treatment-related adverse events. The drug has now been approved for use in the United States and Europe, and, although the exact positioning of this biologic in clinical practice is yet to be defined, it represents an important new chapter in our armamentarium of treatment options for this population. In this review, we will highlight key considerations to be made by providers when using this agent in clinical practice.

Lymphocyte 'homing' and chronic inflammation.

Chronic inflammation is a response to prolonged exposure to injurious stimuli that harm and destroy tissues and promote lymphocyte infiltration into inflamed sites. Following progressive accumulation of lymphocytes, the histology of inflamed tissue begins to resemble that of peripheral lymphoid organs, which can be referred to as lymphoid neogenesis or formation of tertiary lymphoid tissues. Lymphocyte recruitment to inflamed tissues is also reminiscent of lymphocyte homing to peripheral lymphoid organs. In the latter, under physiological conditions, homing receptors expressed on lymphocytes adhere to vascular addressin expressed on high endothelial venules (HEVs), initiating a lymphocyte migration process composed of sequential adhesive interactions. Intriguingly, in chronic inflammation, HEV-like vessels are induced de novo, despite the fact that the inflamed site is not originally lymphoid tissue, and these vessels contribute to lymphocyte recruitment in a manner similar to physiological lymphocyte homing. In this review, we first describe physiological lymphocyte homing mechanisms focusing on vascular addressins. We then describe HEV-like vessel-mediated pathogenesis seen in various chronic inflammatory disorders such as Helicobacter pylori gastritis, inflammatory bowel disease (IBD), autoimmune pancreatitis and sclerosing sialadenitis, as well as chronic inflammatory cell neoplasm MALT lymphoma, with reference to our work and that of others.

A myriad of functions and complex regulation of the CCR7/CCL19/CCL21 chemokine axis in the adaptive immune system.

The chemokine receptor CCR7 and its ligands CCL19 and CCL21 control a diverse array of migratory events in adaptive immune function. Most prominently, CCR7 promotes homing of T cells and DCs to T cell areas of lymphoid tissues where T cell priming occurs. However, CCR7 and its ligands also contribute to a multitude of adaptive immune functions including thymocyte development, secondary lymphoid organogenesis, high affinity antibody responses, regulatory and memory T cell function, and lymphocyte egress from tissues. In this survey, we summarise the role of CCR7 in adaptive immunity and describe recent progress in understanding how this axis is regulated. In particular we highlight CCX-CKR, which scavenges both CCR7 ligands, and discuss its emerging significance in the immune system.

Oral treatment with a novel small molecule alpha 4 integrin antagonist, AJM300, prevents the development of experimental colitis in mice.

BACKGROUND AND AIMS: Inhibition of lymphocyte trafficking by treatment with an anti-α4 integrin antibody has been clinically validated as a therapeutic approach for inflammatory bowel disease (IBD), and the orally effective 'anti-α4 integrin therapy' may be more convenient in clinical practice. The aim of this study was to investigate the pharmacological profile and anti-inflammatory effect of a novel, orally active small molecule α4 integrin antagonist, AJM300. METHODS: The binding specificity/potency of HCA2969 (the active metabolite of AJM300) were investigated in vitro. The pharmacodynamics for α4 integrin antagonism of AJM300 was investigated in mice. The anti-inflammatory effect of AJM300 fed in a diet and the anti-α4 integrin monoclonal antibody was evaluated in a mouse colitis model induced by transfer of IL-10 deficient T cells. RESULTS: HCA2969 selectively inhibited the in vitro binding of α4 integrin (α4ß7/α4ß1) to the cell adhesion molecules. Oral treatment with AJM300 dose-dependently inhibited lymphocyte homing to Peyer's patches and increased the peripheral lymphocyte count in the same dose range. AJM300 dose-dependently prevented the development of experimental colitis in mice. A significant inhibition of colon weight increase was accompanied by inhibition of T-cell infiltration into the lamina propria of colon. The maximum efficacy of AJM300 (1% diet) was comparable to that achieved by the saturated α4 integrin blockade with antibody. CONCLUSIONS: Oral treatment with the selective small molecule α4 integrin antagonist (AJM300) prevented the development of colitis and its efficacy was comparable to that of the anti-α4 integrin antibody.

Effects of vasoactive intestinal peptide or somatostatin on the expression of MADCAM-1 in the intestinal mucosa of rats with multiple organ dysfunction synarome / 中华急诊医学杂志

Objective To investigate the effects of somatostatin(SST)or vasoaetive intestinal peptide (VIP)on the expression of MAdCAM-1 in the intestinal muecosa of rats with multiple organ dysfunction syndrome (MODS)and its significance of prevention and treatment of MODS.Method Thirty six Wistar male rats were randomly divided into 6 groups(6 rats in each group),including control group,VIP group 1 and SST group1 (rats treated with VIP and SST respectively),MODS group(rats with MODS),VIP group 2 and SST group 2(NODS rats treated with VIP and SST respectively).The rat model of MODS(system inflammatory response syndrome,＞2 or-gans dysfunction)was established by occlusion of superior mesenteric arteries.0.2 ρmol·g-1 h -11 VIP or SST by intravenous injection combined with 0.25 ρmol/g VIP or SST by intraperitoneal injection were injected into rats.In each group,intestinal lymphocytes from rats labeled with 51 Cr were infused into rat veins and were quantified with γcounter in GALT.The expression of MAdCAM-1 in the intestinal mucosa was measured by western blot.Inflam-mation in the intestinal mucosa was evaluated with histological sections.Student's t test was used to assess differ-ence between the experiment group and the control group.Results In VIP group l and SST group 1,the peak values of MAdCAM-1 expression in diffusive lymphatic tissue of small intestinal were 157.67±2.52 and 154.33±3.22.and those in Peyer patches were 136.00±1.00 and 137.00±1.00.There were no significant difference when compared with control group(165.33±1.53,152.67±2.31,P＞0.05).The percentage of 51 Cr-lympho-cytes in diffusive lymphatic tissue of small intestine(1.04%±0.59%,1.01%±0.83%)showed no significant difference from control group(1.07%±0.61%,P＞0.05),and those in Peyer patches(1.83%±0.90%,1.56%±0.64%)were significantly less than control group(3.85%±2.02%,P＜0.05).In VIP group 2 and SST group 2,the peak values of MAdCAM-1 expression in diffusive lymphatic tissue of small intestinal(158.00±2.65,154.33±1.53)and Peyer patches(156.33±1.53.151.33±2.31)were significantly less than MODS group(175.33±2.52,173.00±2.65,P＜0.05).The percentage of 51 Cr-lymphocytes in diffusive lymphafic tissue of small intestine(1.58%±0.42%,1.45%±0.26%)and Peyer patches(2.14%±1.49%,0.81%±0.35%)were significantly less than MODS group(3.23%±1.69%,5.04%±1.23%,P＜0.05)and the se-vere histopathological danlage in intestine was relieved.Conclusions VIP or SST reduced intestinal lymphoeytes homing to GALT in rats with MODS through suppressing the expression of MAdCAM-1,and attenuated the inflam-matory injure in the intestinal mucosa.