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Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, is a chronic inflammatory condition of the gastrointestinal (GI) tract. Currently, it is treated with immunosuppressant or biologics that often induce severe adverse effects. Thus, there is an urgent clinical need for more specific treatments. To provide a valid therapeutic tool for IBD therapy, in this work we developed biomimetic nanovesicles by manipulating leukocyte membranes to exploit mechanisms of T-cell recruitment during inflammation. A subset of T-lymphocytes participates in homing to inflamed tissue in the gastrointestinal tract by overexpressing the α4β7 integrin, which is responsible for binding to its receptor on the endothelial membrane, the mucosal addressin cell adhesion molecule 1. Based on this principle, we engineered biomimetic vesicles, referred to as specialized leukosomes (SLKs), which are leukocyte-like carriers 'doped' with the α4β7 integrin over-induced in purified immune cells. We tested SLKs in an in vivo murine model of IBD induced by treatment with dextran sulfate sodium. Notably, treatment of IBD mice with SLKs allowed us to observe a reduction of inflammation (favorable modulation of both pro- and anti-inflammatory genes, as well as reduction of immune cells infiltration into the colon tissue), and a consequent enhanced intestinal repair (low epithelial damage). In this study, we demonstrate that biological-derived nanoparticles can be used not only as naturally targeted drug delivery systems, but also as nano-therapeutics endowed with intrinsic anti-inflammatory properties.

Aim: We investigate MAdCAM-1 as a reliable target to detect active bowel inflammation for selective noninvasive nanodiagnostics. Materials & methods: We coupled anti-MAdCAM-1 antibodies to manganese oxide nanoparticles, and analyzed nanoconjugate biodistribution and safety in murine model of inflammatory bowel disease by imaging and histology. Results: Nanoparticles were stable and nontoxic. Upon administration in colitic mice, anti-MAdCAM-1 functionalized nanoparticles preferentially localized in the inflamed bowel, whereas untargeted nanoparticles were more rapidly washed out. Nanoparticles did not induce lesions in nontarget organs. Conclusion: Anti-MAdCAM-1 functionalized nanoparticles detected active bowel inflammation foci, accurately following MAdCAM-1 expression pattern. These nanoconjugates could be a promising noninvasive imaging system for an early and accurate follow-up in patients affected by acute colitis.

Ulcerative colitis (UC) is one of the two phenotypic expressions of inflammatory bowel disease (IBD) where mucosal inflammation typically starts at the anal margin and extends proximally to the rectosigmoid, descending colon, or above. The therapeutic approach of the past decades consisted of a combination of 5-ASA, azathioprine and biologic agents targeting TNFalpha. In 2014, a second class of biologic therapeutics, targeting lymphocyte trafficking and cell adhesion was introduced with vedolizumab, a humanized alpha 4 beta 7 integrin antagonist. This chapter reviews efficacy and safety of vedolizumab and other biologic drugs in this class that are under development.

Although the homing of lymphocytes to GALT has been extensively studied, little is known about how high endothelial venules (HEVs) within Peyer’s patches (PPs) are patterned to display dominantly mucosal addressin cell adhesion molecule 1 (MAdCAM-1). In this study, we report that Nkx2-3–deficient mice show gradual loss of MAdCAM-1 in PPs postnatally and increased levels of mRNA for peripheral lymph node addressin (PNAd) backbone proteins as well as enhanced expression of MECA79 sulfated glycoepitope at the luminal aspect of HEVs, thus replacing MAdCAM-1 with PNAd. Induction of PNAd in mutant PPs requires lymphotoxin β receptor activity, and its upregulation needs the presence of mature T and B cells. Furthermore, treatment with MECA-79 anti-PNAd mAb in vivo effectively blocks lymphocyte homing to mutant PPs. Despite the replacement of MAdCAM-1 by PNAd in HEV endothelia, lymphocytes could efficiently home to PPs in mutant mice. We conclude that although Nkx2-3 activity controls the addressin balance of HEVs in GALT, the general HEV functionality is preserved independently from Nkx2-3, indicating a substantial plasticity in the specification of GALT HEV endothelium.

Increased understanding of the pathogenesis of inflammatory bowel diseases (IBDs) has led to new therapeutic strategies. One of these is to target the molecules that regulate interactions between leukocytes and endothelial cells at sites of inflammation (mainly leukocyte integrins and endothelial cell adhesion molecules of the immunoglobulin superfamily). These molecules have been validated as therapeutic targets for IBD; several have shown efficacy, and 2 have been approved by the Food and Drug Administration for treatment of IBD. Natalizumab, the first anti-integrin antibody tested for treatment of IBD, blocks the α4 subunit. Although it is effective, its clinical use has been limited by its association with risk of progressive multifocal leukoencephalopathy. Other, allegedly more selective drugs that affect leukocyte recruitment in the gastrointestinal tract have been developed or are under investigation and could increase safety. These include vedolizumab and AMG 181 (antibodies against α4β7), etrolizumab (anti-β7), and PF-00547659 (anti-mucosal vascular addressin cell adhesion molecule 1). Other agents have been developed to block α4 (the small molecule AJM300), CCR9 (the small molecule CCX282-B), and CXCL10 (the antibody eldelumab). We review the scientific rationale for inhibiting interactions between leukocytes and endothelial cells to reduce intestinal inflammation and analyze the clinical studies that have been performed to test these new molecules, with particular attention to safety. We propose an evidence-based clinical positioning of this class of drugs.

Inflammatory bowel diseases (IBDs) are a group of idiopathic, chronic immune-mediated diseases characterized by an aberrant immune response, including imbalances of inflammatory cytokine production and activated innate and adaptive immunity. Selective blockade of leukocyte migration into the gut is a promising strategy for the treatment of IBD. This study explored the effect of the immunomodulating tellurium compound ammonium trichloro (dioxoethylene-o,o') tellurate (AS101) on dextran sodium sulfate (DSS)-induced murine colitis. Both oral and intraperitoneal administration of AS101 significantly reduced clinical manifestations of IBD. Colonic inflammatory cytokine levels (IL-17 and IL-1β) were significantly down-regulated by AS101 treatment, whereas IFN-γ was not affected. Neutrophil and α4β7(+) macrophage migration into the tissue was inhibited by AS101 treatment. Adhesion of mesenteric lymph node cells to mucosal addressin cell adhesion molecule (MAdCAM-1), the ligand for α4β7 integrin, was blocked by AS101 treatment both in vitro and in vivo. DSS-induced destruction of colonic epithelial barrier/integrity was prevented by AS101, via up-regulation of colonic glial-derived neurotrophic factor, which was found previously to regulate the intestinal epithelial barrier through activation of the PI3K/AKT pathway. Indeed, the up-regulation of glial-derived neurotrophic factor by AS101 was associated with increased levels of colonic pAKT and BCL-2 and decreased levels of BAX. Furthermore, AS101 treatment reduced colonic permeability to Evans blue and decreased colonic TUNEL(+) cells. Our data revealed multifunctional activities of AS101 in the DSS-induced colitis model via anti-inflammatory and anti-apoptotic properties. We suggest that treatment with the small, nontoxic molecule AS101 may be an effective early therapeutic approach for controlling human IBD.

Background/Aims: Integrin activation and lymphocyte migration to the vascular intima is a key event in early atherosclerosis. α4β7 integrin (LPAM-1) and its ligand, mucosal addressin cell adhesion molecule (MAdCAM-1) are known to play an important role in homing of activated lymphocytes to gut-associated lymphoid tissues. However, it is unclear whether α4β7 integrin is involved in the pathogenesis of atherosclerosis. Methods: The expressions of α4β7 integrin and its ligands in atherosclerosis plaques from 12 week high fat diet (HFD) fed ApoE-/- and C57BL/6 mice were examined using immunofluorescent and immunohistochemical assays, respectively. We also generated ApoE/β7 double deficient mice and compared atherosclerotic lesion development in β7+/+ApoE-/- and β7-/-ApoE-/- mice that were fed with HFD for 12 weeks. Results: We found an upregulation of α4β7 integrin and its ligands VCAM-1 and MAdCAM-1 at atherosclerosis plaques in Apolipoprotein E deficient (ApoE-/-) mice fed with HFD for 12 weeks. Over the 12 week HFD period, peripheral blood lymphocyte (PBL) expression of α4β7 integrin increased in parallel with aortic lesion size. A removal of α4β7 integrin by genetic deletion of the β7 chain in the ApoE-/- mouse resulted in a markedly decreased 12 week-HFD atherosclerotic plaque area. β7-/- ApoE-/- macrophages showed reduced acetylated and native LDL uptake and phagocytic activity, revealing possible roles for α4β7 at two distinct stages of macrophage dysfunction during atherogenesis. Finally, a reduced activity of integrin downstream signalling components focal adhesion kinase (FAK) and MAPK/ERK1/2 in macrophage indicates their possible engagement during α4β7 integrin signalling in atherosclerosis. Conclusions: Together our results reveal a critical role of α4β7 in diet-induced atherosclerosis in mouse.

Integrin α4 β7 mediates both rolling and firm adhesion of lymphocytes by modulating its affinity to the ligand: mucosal addressin cell adhesion molecule-1 (MAdCAM-1). Integrin activation is associated with allosteric reshaping in the β subunit I (βI) domain. A prominently conformational change comprises displacement of the α1 and α7 helices in the βI domain, suggesting that the location of these helices is important for the change in integrin affinity. In the present study, we report that the hydrophobic contacts between the center of the β7 I domain and the α1/α7 helices play critical roles in keeping α4 β7 in a low-affinity state. Using molecular dynamics simulation, we identified nine hydrophobic residues that might be involved in the critical hydrophobic contacts maintaining integrin in a low-affinity state. Integrin β7 I domain exhibited a lower binding free energy for ligand after disrupting these hydrophobic contacts by substituting the hydrophobic residues with Ala. Moreover, these α4 β7 mutants not only showed high-affinity binding to soluble MAdCAM-1, but also demonstrated firm cell adhesion to immobilized MAdCAM-1 in shear flow and enhanced the strength of the α4 β7 -MAdCAM-1 interaction. Disruption of the hydrophobic contacts also induced the active conformation of α4 β7 . Thus, the findings obtained in the present study reveal an important structural basis for the low-affinity state of integrin.

Seminoma, the most common testicular malignant neoplasm, originates from germ cells and is characterized by the presence of numerous tumour-infiltrating lymphocytes (TILs). Although it is widely accepted that TILs function in surveillance and cytotoxicity in various tumours including seminoma, detailed mechanisms governing TIL recruitment are not fully understood. It has been shown that high endothelial venule (HEV)-like vessels are induced in inflamed and neoplastic tissues and contribute to lymphocyte recruitment in a manner similar to the way physiological lymphocyte homing occurs in secondary lymphoid organs. Here, we report that HEV-like vessels, which express MECA-79(+) 6-sulfo sialyl Lewis X-capped structures, are induced in TIL aggregates in seminoma, and that such vessels potentially recruit circulating lymphocytes, as an E-selectin•IgM chimera bound these vessels in a calcium-dependent manner. These HEV-like vessels express intercellular adhesion molecule 1 (ICAM-1), but not vascular cell adhesion molecule 1 (VCAM-1) or mucosal addressin cell adhesion molecule 1 (MAdCAM-1), which likely contributes to lymphocyte firm attachment. We also found that the number of T cells attached to the luminal surface of HEV-like vessels was greater than the number of B cells (p < 0.0001). Interestingly, while CD8(+) cytotoxic T lymphocytes (CTLs) attached to the lumen of HEV-like vessels were scarcely detected, significant numbers of proliferative CTLs were observed outside vessels. These histological findings strongly suggest that TILs, particularly T cells, are recruited to seminoma tissues via HEV-like vessels, and that tumour-infiltrating CTLs then undergo proliferation after transmigration through HEV-like vessels in testicular seminoma.

For many years, physicians had only antitumour necrosis factor (anti-TNF) antibodies as biologicals for the treatment of IBD. With the regulatory approval of vedolizumab, a completely new mechanism of action was introduced into the therapeutic armamentarium of IBD specialists: vedolizumab is an ‘integrin antagonist’ binding to the α4β7 integrin expressed on the surface of mononuclear cells such as T-lymphocytes.1 Circulating blood T-cells require binding of α4β7 integrin to mucosal addressin cell adhesion molecule-1 (MAdCAM-1) expressed by the endothelial cells of the GI tract to be able to migrate into the mucosal layers.1 To prevent the migration of inflammatory mononuclear cells into the inflamed mucosa in patients with IBD, integrin antagonists have been developed. Several antagonists of integrin–adhesion molecule interactions are approved or under clinical development targeting either the α4β7 integrin heterodimer, the α4 integrin, the β7 integrin or MAdCAM-1 (such as etrolizumab, a β7 integrin antibody; and PF-00547659,17, an anti-MAdCAM-1 antibody).2 It is important to understand the mechanism of action of those therapies exactly to be able to adapt them to specific patient needs. …

Dietary fat has multiple roles on human health, and some dietary fat is used to treat organic diseases because of its anti-inflammatory effect. It is commonly accepted that omega-3 polyunsaturated fatty acid (PUFA) is beneficial on ischemic heart disease or rheumatic arthritis. On the contrary, effect of omega-3-PUFA on Crohn's disease remained controversial. That effect of omega-3 PUFA differs according to the location of inflamed intestine was hypothesized. To elucidate this hypothesis, to investigate the role of dietary fat on disease activity in different kind of murine models of intestinal inflammatory diseases was planned. The effect of omega-3 PUFA on small intestinal Crohn's disease model and large intestinal Crohn's disease model of mice. Chronic colitis model C57BL/6 mice received two cycles of dextran sodium sulfate solution treatment to induce chronic colitis. Feeding of omega-3 fat-rich diets exacerbated colitis with decrease in adiponectin expression. Chronic small intestinal inflammation model: SAMP1/Yit mice showed remarkable inflammation of the terminal ileum spontaneously. Feeding of omega-3 fat-rich diets for 16 weeks significantly ameliorated the inflammation of the terminal ileum. Enhanced infiltration of leukocytes and expression of mucosal addressin cell adhesion molecule-1 in intestinal mucosa was significantly decreased by omega-3 fat-rich diets treatment. Omega-3 PUFA has dual role, pro-/anti-inflammatory, on intestinal inflammatory diseases. The role of omega-3 fat and the potential for immunonutrition in inflammatory conditions of the gastrointestinal tract will be discussed.

Blood-borne neutrophils are excluded from entering lymph nodes across vascular portals termed high endothelial venules (HEVs) because of lack of expression of the CCR7 homeostatic chemokine receptor. Induction of sterile inflammation increases neutrophil entry into tumor-draining lymph nodes (TDLNs), which is critical for induction of antitumor adaptive immunity following treatments such as photodynamic therapy (PDT). However, the mechanisms controlling neutrophil entry into TDLNs remain unclear. Prior evidence that IL-17 promotes neutrophil emigration to sites of infection via induction of CXCL2 and CXCL1 inflammatory chemokines raised the question of whether IL-17 contributes to chemokine-dependent trafficking in TDLNs. In this article, we demonstrate rapid accumulation of IL-17–producing Th17 cells in the TDLNs following induction of sterile inflammation by PDT. We further report that nonhematopoietic expression of IL-17RA regulates neutrophil accumulation in TDLNs following induction of sterile inflammation by PDT. We show that HEVs are the major route of entry of blood-borne neutrophils into TDLNs through interactions of l-selectin with HEV-expressed peripheral lymph node addressin and by preferential interactions between CXCR2 and CXCL2 but not CXCL1. CXCL2 induction in TDLNs was mapped in a linear pathway downstream of IL-17RA–dependent induction of IL-1β. These results define a novel IL-17–dependent mechanism promoting neutrophil delivery across HEVs in TDLNs during acute inflammatory responses.

Enhanced cell expression of MAdCAM-1 is critical in tissue recruitment of lymphocytes in response to stimuli expressing the α4β7 integrin. MAdCAM-1 is well characterized in gut mucosa with emerging evidence of hepatic expression. (i) Compare quantitative/semi-quantitatively MAdCAM-1 expression in relation to early and advanced liver diseases (ii) Define the fine structure of vascular plexuses/lymphatics in the portal tract on which MAdCAM-1 is expressed. Using alkaline phosphatase anti-alkaline phosphatase methodology on paraffin embedded tissue sections (n = 28) from cirrhotic individuals who underwent orthotopic liver transplant, we evaluated MAdCAM-1 expression and compared with pre-cirrhotic, fulminant hepatitis B, and non-cirrhotic portal hypertension tissue sections. The positive controls included normal colon tissue with negative controls without primary antibody and isotype-matched purified IgG. We developed a real time PCR to quantify levels of MAdCAM-1 mRNA in our samples. MAdCAM-1 was expressed in 27/28 of the cirrhotic sections, localized primarily to septal areas within (i) endothelium of the peribiliary vascular plexus (PBP) (ii) lymphoid aggregates, with absence from normal, non-cirrhotic portal hypertension and pre-cirrhotic livers. There was significant upregulation of MAdCAM-1 mRNA in cirrhosis (p

Crohn's disease and ulcerative colitis are chronic inflammatory bowel diseases that have been treated with corticosteroids, 5-aminosalicates and thiopurines, but therapeutic options have been broadened with the arrival of anti-tumor necrosis factor antibodies. In this article we reviewed the current evidence-based approach to inflammatory bowel disease, the modifications that have been made to existing therapies and discussed new drugs that have shown success in clinical trials. The new drugs discussed here are those that disturb lymphocyte homing to the gut (natalizumab, vedolizumab and anti-mucosal addressin cellular adhesion molecule); one that blocks interleukin (IL)-12 as well as the IL-23/T helper 17 (Th17) axis (ustekinumab) and one that blocks the signaling of multiple cytokines (tofacitinib).

Background and Purpose AMG 181 is a human anti-α4β7 antibody currently in phase 1 and 2 trials in subjects with inflammatory bowel diseases. AMG 181 specifically targets the α4β7 integrin heterodimer, blocking its interaction with mucosal addressin cell adhesion molecule-1 (MAdCAM-1), the principal ligand that mediates α4β7 T cell gut-homing. Experimental Approach We studied the in vitro pharmacology of AMG 181, and the pharmacokinetics and pharmacodynamics of AMG 181 after single or weekly i.v. or s.c. administration in cynomolgus monkeys for up to 13 weeks. Key Results AMG 181 bound to α4β7, but not α4β1 or αEβ7, and potently inhibited α4β7 binding to MAdCAM-1 (but not vascular cell adhesion molecule-1) and thus inhibited T cell adhesion. Following single i.v. administration, AMG 181 Cmax was dose proportional from 0.01 to 80 mg·kg−1, while AUC increased more than dose proportionally. Following s.c. administration, dose-proportional exposure was observed with single dose ranging from 5 to 80 mg·kg−1 and after 13 weekly doses at levels between 20 and 80 mg·kg−1. AMG 181 accumulated two- to threefold after 13 weekly 80 mg·kg−1 i.v. or s.c. doses. AMG 181 had an s.c. bioavailability of 80%. The linear elimination half-life was 12 days, with a volume of distribution close to the intravascular plasma space. The mean trend for the magnitude and duration of AMG 181 exposure, immunogenicity, α4β7 receptor occupancy and elevation in gut-homing CD4+ central memory T cell count displayed apparent correlations. Conclusions and Implications AMG 181 has in vitro pharmacology, and pharmacokinetic/pharmacodynamic and safety characteristics in cynomolgus monkeys that are suitable for further investigation in humans.

Mucosal addressin cell adhesion molecule (MAdCAM) binds integrin α4β7. Their interaction directs lymphocyte homing to mucosa-associated lymphoid tissues. The interaction between the two immunoglobulin superfamily (IgSF) domains of MAdCAM and integrin α4β7 is unusual in its ability to mediate either rolling adhesion or firm adhesion of lymphocytes on vascular surfaces. We determined four crystal structures of the IgSF domains of MAdCAM to test for unusual structural features that might correlate with this functional diversity. Higher resolution 1.7- and 1.4-Å structures of the IgSF domains of MAdCAM in a previously described crystal lattice revealed two alternative conformations of the integrin-binding loop, which were deformed by large lattice contacts. New crystal forms in the presence of two different Fabs to MAdCAM demonstrate a shift in IgSF domain topology from the I2- to I1-set, with a switch of integrin-binding loop from CC' to CD. The I1-set fold and CD loop appear biologically relevant. The different conformations seen in crystal structures suggest that the integrin-binding loop of MAdCAM is inherently flexible. This contrasts with rigidity of the corresponding loops in vascular cell adhesion molecule, intercellular adhesion molecule (ICAM)-1, ICAM-2, ICAM-3, and ICAM-5 and may reflect a specialization of MAdCAM to mediate both rolling and firm adhesion by binding to different α4β7 integrin conformations.

Summary Aims Warthin’s tumour is composed of bilayered oncocytic epithelium and organised lymphoid stroma, which resembles mucosa-associated lymphoid tissue (MALT); however, the histogenesis of the lymphoid stroma is not fully understood. We hypothesised that lymphocytes consisting of the stroma are recruited via high endothelial venules (HEVs) by the mechanism operating in normal lymphocyte homing in secondary lymphoid organs. The aim of this study was to determine immunohistochemically the molecules expressed on these HEVs. Methods Tissue sections of Warthin’s tumour ( n = 10) were immunostained for vascular addressin-related antigens including peripheral lymph node addressin (PNAd) and mucosal addressin cell adhesion molecule 1 (MAdCAM-1). An L-selectin·IgM chimera in situ binding assay was also carried out. Triple immunostaining for PNAd, CD3, and CD20/CD79a was performed to determine which lymphocyte subsets are closely associated with these HEVs. Results HEVs in the lymphoid stroma of Warthin’s tumour express PNAd, which is detected by MECA-79 as well as recently developed monoclonal antibodies S1 and S2. These HEVs were bound by L-selectin·IgM chimeras in a calcium-dependent manner, and numbers of lymphocytes, particularly T cells, attached to these HEVs. Conclusions The lymphoid stroma of Warthin’s tumour is most likely developed by lymphocytes recruited via HEVs.

信州大学博士（医学）・学位論文・平成24年3月31日授与（甲第946号）・丸山 雅史, This is a non-final version of an article published in final form in PANCREAS. 42(1):53-59 (2013)., Objectives: Type 1 autoimmune pancreatitis (AIP) is histologically characterized by dense lymphoplasmacytic infiltration and marked storiform fibrosis, manifestations associated with pancreatic ducts. Such periductal lymphocyte recruitment is thought to be elicited by dysregulation of mechanisms governing physiological lymphocyte homing. The present study was undertaken to determine whether vascular addressins including peripheral lymph node addressin and mucosal addressin cell adhesion molecule 1 (MAdCAM-1) play a role in type 1 AIP histogenesis. Methods: Tissue sections of type 1 AIP and tumor-associated non-AIP chronic pancreatitis, as well as normal pancreas, were subjected to immunohistochemical analysis using vascular addressin-related antibodies. Results: The number of periductal mouse endothelial cell antigen 79-positive high endothelial venule (HEV)-like vessels was increased in type 1 AIP relative to that seen in non-AIP chronic pancreatitis, whereas the number of MAdCAM-1-positive HEV-like vessels did not differ between the 2 conditions. Mouse endothelial cell antigen 79 antigens are expressed on duct-forming epithelial cells not only in pancreas but also in salivary glands, which often harbor extrapancreatic lesions in type 1 AIP. Conclusions: Type 1 AIP can be characterized by periductal induction of MECA-79-positive HEV-like vessels. MECA-79-positive 6-sulfo sialyl Lewis X-related carbohydrate antigens expressed on duct-forming epithelial cells could be associated with type 1 AIP pathogenesis., Article, PANCREAS. 42(1):53-59 (2013)

Peripheral node addressin (PNAd) marks high endothelial venules (HEV), which are crucial for the recruitment of lymphocytes into lymphoid organs in non-mucosal tissue sites. PNAd is a sulfated and fucosylated glycoprotein recognized by the prototypic monoclonal antibody MECA-79. PNAd is the ligand for L-selectin, which is expressed on the surface of naïve and central memory T cells, where it mediates leukocyte rolling on vascular endothelial surfaces. Although PNAd was first identified in the HEV of peripheral lymph nodes, recent work suggests a critical role for PNAd in the context of chronic inflammatory diseases, where it can be used as a marker for the formation of tertiary lymphoid organs (TLO). TLO form in tissues affected by sustained inflammation, such as the tumor microenvironment (TME), where they function as local sites of adaptive immune cell priming. This allows for specific B- and T-cell responses to be initiated or reactivated in inflamed tissues without dependency on secondary lymphoid organs (SLO). Recent studies of cancer in mice and humans have identified PNAd as a biomarker of improved disease prognosis, and blockade of PNAd or its ligand, L-selectin, abrogates protective anti-tumor immunity in murine models. This review examines pathways regulating PNAd biosynthesis by the endothelial cells integral to HEV and the formation and maintenance of lymphoid structures throughout the body, particularly in the setting of cancer.

The cell-surface glycoprotein vascular cell adhesion molecule-1 (VCAM-1; ref. 1) mediates intercellular adhesion by specific binding to the integrin very-late antigen-4 (VLA-4, alpha 4 beta 1; ref. 3). VCAM-1, with the intercellular adhesion molecules ICAM-1, ICAM-2, ICAM-3 and the mucosal vascular addressin MAd-CAM-1, forms an integrin-binding subgroup of the immunoglobulin superfamily. In addition to their clinical relevance in inflammation, these molecules act as cellular receptors for viral and parasitic agents. The predominant form of VCAM-1 in vivo has an amino-terminal extracellular region comprising seven immunoglobulin-like domains. Functional studies have identified a conserved integrin-binding motif in domains 1 and 4, variants of which are present in the N-terminal domain of all members of the immunoglobulin superfamily subgroup. We report here the crystal structure of a VLA-4-binding fragment composed of the first two domains of VCAM-1. The integrin-binding motif (Q38IDSPL) is highly exposed and forms the N-terminal region of the loop between beta-strands C and D of domain 1. This motif exhibits a distinctive conformation which we predict will be common to all the integrin-binding IgSF molecules. These, and additional data, map VLA-4 binding to the face of the CFG beta-sheet, the surface previously identified as the site for intercellular adhesive interactions between members of the immunoglobulin superfamily.

Acute peritonitis is a frequent medical condition that can trigger severe sepsis as a life-threatening complication. Neutrophils are first-responders in infection but recruitment mechanisms to the abdominal cavity remain poorly defined. Here, we demonstrate that high endothelial venules (HEVs) of the greater omentum constitute a main entry pathway in TNFα-, Escherichia coli (E. coli)- and caecal ligation and puncture-induced models of inflammation. Neutrophil transmigration across HEVs is faster than across conventional postcapillary venules and requires a unique set of adhesion receptors including peripheral node addressin, E-, L-selectin and Mac-1 but not P-selectin or LFA-1. Omental milky spots readily concentrate intra-abdominal E. coli where macrophages and recruited neutrophils collaborate in phagocytosis and killing. Inhibition of the omental neutrophil response exacerbates septic progression of peritonitis. This data identifies HEVs as a clinically relevant vascular recruitment site for neutrophils in acute peritonitis that is indispensable for host defence against early systemic bacterial spread and sepsis., Neutrophils are critical in preventing the transition of acute peritoneal infection to sepsis. Here the authors show in three mouse models of peritonitis that neutrophils enter the abdominal cavity via high endothelial venules of the greater omentum, and characterize adhesion molecules involved.

Under normal and pathological conditions, lymphocyte migration into the gastrointestinal mucosa to form gut-associated lymphoid tissue is mediated by the L-selectin ligand peripheral lymph node addressin and the integrin α4β7 ligand mucosal addressin cell adhesion molecule 1 (MAdCAM-1) expressed on high endothelial venules (HEVs) and HEV-like vessels. In this review, we discuss these two distinct lymphocyte homing systems involved in the pathogenesis of chronic inflammatory gastrointestinal diseases with reference to our and others' previously published works. We also describe a recently developed recombinant integrin α4β7 heterodimeric IgG chimera that can be used as an immunohistochemical reagent to stain functional MAdCAM-1.

In this article, the interactive approach to law is critically analysed. The development of this approach finds its roots in both theoretical perspectives and legal paradigm developments. Addressing issues such as animal biotechnology: issues that are characterised by uncertainties, rapid changes, and moral controversies, require a more interactive legal paradigm so that norm development can respond to developments in society. The interactive legislative approach's basic elements include legal decision-making on a horizontal level (communication) and ongoing legal norm development in interaction with the specific field and society (responsiveness). Both elements strongly depend on a consensus-orientated way of thinking. To start, striving for consensus brings parties together by creating an arena in which parties are willing to co-operate. At the same time striving for consensus can justify the openness and flexibility of norms that are in need for further development. However, in this article, it is shown that for the interactive legislative approach's functioning in practice, a consensus-orientated way of thinking instead seems counterproductive. In furtherance of the argument, the results based on a twofold case-study concerning the regulation of animal biotechnology in Switzerland and the Netherlands are used It is argued that due to a strong focus on consensus within these processes of legal norm development, legal practice faces difficulties stimulating an ongoing process of legal norm development which ensures the flexibility of legal norms. Instead of focusing on consensus, the author suggests legislators should follow an ethos of controversies. The latter contains a way of normative thinking in which the controversies are of main focus.

Although tumor blood vessels have been a major therapeutic target for cancer chemotherapy, little is known regarding the stepwise development of the tumor microenvironment. Here, we use a multicolor Cre-dependent marker system to trace clonality within the tumor microenvironment to show that tumor blood vessels follow a pattern of dynamic clonal evolution. In an advanced melanoma tumor microenvironment, the vast majority of tumor vasculature clones are derived from a common precursor. Quantitative lineage analysis reveals founder clones diminish in frequency and are replaced by subclones as tumors evolve. These tumor-specific blood vessels are characterized by a developmental switch to a more invasive and immunologically silent phenotype. Gene expression profiling and pathway analysis reveals selection for traits promoting upregulation of alternative angiogenic programs such as unregulated HGF-MET signaling and enhanced autocrine signaling through VEGF and PDGF. Furthermore, we show a developmental switch in the expression of functionally significant primary lymphocyte adhesion molecules on tumor endothelium, such as the loss in expression of the mucosal addressin MAdCAM-1, whose counter receptor a4β7 on lymphocytes controls lymphocyte homing. Changes in adhesive properties on tumor endothelial subclones are accompanied by decreases in expression of lymphocyte chemokines CXCL16, CXCL13, CXCL12, CXCL9, CXCL10, and CCL19. These evolutionary patterns in the expressed genetic program within tumor endothelium will have both a quantitative and functional impact on lymphocyte distribution that may well influence tumor immune function and underlie escape mechanisms from current antiangiogenic pharmacotherapies. Cancer Res; 76(6); 1348–53. ©2015 AACR.

Tertiary lymphoid organs (TLOs) have been described within organ allografts, but whether they promote destructive or beneficial alloimmune responses remains controversial. This study aimed to characterize TLO distribution in human chronically rejected renal allografts and to explore their functions.A total of 29 explanted chronically rejected and 12 acutely rejected renal allografts were analyzed by immunohistochemistry. The distribution of TLOs, T cells, follicular dendritic cells, B cells, and follicular regulatory T (Tfr) cells, as well as Ki67, peripheral lymph node addressin (PNAd), podoplanin, AID, IL-17, IL-21, IL-10, and C4d expression were detected by immunohistochemistry. Correlations between lymphoid neogenesis and the expression of IL-17, IL-21, C4d, podoplanin, IL-10, and Foxp3 were evaluated. In addition, the duration of graft function was compared between allografts that harbored or lacked TLOs.TLOs were detected in 27.6% of chronically rejected renal grafts, but they rarely had germinal centers. Lymphoid neogenesis negatively correlated with CXCR5 expression, and almost completely correlated with IL-17 expression. Those grafts that harbored a TLO functioned for an average of 5.98 years and those without a TLO lasted only about half as long with an average of 2.91 years. However, in grafts that harbored a TLO, Foxp3(+) cells were comparitively less than those without a TLO. Foxp3(+)CXCR5(+) Tfr cells and IL-10(+) cells were rare in grafts, irrespective of the presence of a TLO.TLOs in chronically rejected kidney allografts may be an epiphenomenon of the inflammatory process that is related to graft duration.

Rap1-GTP activates leukocyte function-associated antigen-1 (LFA-1) to induce arrest on the high endothelial venule (HEV). Here we show that Rap1-GDP restrains rolling behaviours of T cells on the peripheral lymph node addressin (PNAd), P-selectin and mucosal addressin cell adhesion molecule-1 (MadCAM-1) by inhibiting tether formation. Consequently, Rap1 deficiency impairs homing of naive T cells to peripheral lymph nodes, but accelerates homing of TH17 and TH1 cells to the colon, resulting in spontaneous colitis with tumours. Rap1-GDP associates with and activates lymphocyte-oriented kinase, which phosphorylates ERM (ezrin, radixin and moesin) in resting T cells. Phosphomimetic ezrin reduces the rolling of Rap1-deficient cells, and thereby decreases their homing into the colon. On the other hand, chemokines activate Rap1 at the plasma membrane within seconds, and Rap1-GTP binds to filamins, which diminishes its association with the β2 chain of LFA-1 and results in LFA-1 activation. This Rap1-dependent regulation of T-cell circulation prevents the onset of colitis., Rap1, a member of the Ras family of small guanine triphosphatases, mediates lymphocyte adhesion to high endothelial venules. Here the authors show that depending on its activation status Rap1 plays a dual role in T cell adhesion and by regulating T cell homeostasis is involved in the protection from colitis.

Crohn's disease and ulcerative colitis are two chronic inflammatory bowel diseases. Current biologic therapies are limited to blocking tumor necrosis factor alpha. However, some patients are primary non-responders, experience a loss of response, intolerance or side effects defining the urgent unmet need for novel treatments. The rapid recruitment and inappropriate retention of leukocytes is a hallmark of chronic inflammation and a potentially promising therapeutic target. We discuss the immunological mechanisms of leukocyte homing and adhesion in the gut mucosa. The interaction of lymphocytes (CD4+ T-cells, CD8+ T-cells, T(REG), T(H)1, T(H)17, B-cells), monocytes, macrophages, dendritic cells and granulocytes with endothelial and epithelial cells through integrins [α4β7 (LPAM-1), α(E)β₇ (HML1 Human Mucosal Lymphocyte Antigen 1), α₄β₁ (VLA-4), α(L)β₇, (LFA-1)] and their ligands immunoglobulin superfamily cellular adhesion molecules (CAM) (MAdCAM-1 Mucosal Addressin Cellular Adhesion Molecule 1, ICAM-1 Intercellular Cell Adhesion Molecule, VCAM-1 Vascular Cell Adhesion Molecule), fibronectin as well as chemokine receptors (CCR2, CCR4, CCR5, CCR7, CCR9, CCR10, CXCR3, CX3CR1) and chemokines [CCL5, CCL25 (TECK Thymus Expressed Chemokine), CCL28, CX3CL1, CXCL10, CXCL12] in the process of gut homing is critically reviewed and summarized in scientific cartoons. Moreover, we discuss the clinical trial results of approved and investigational antibodies and small molecules including natalizumab (anti-α₄ Tysabri®, Antegren®), AJM300 (anti-α4), etrolizumab (anti-β7, rhuMAb-Beta7), vedolizumab (anti-α4β7, LDP-02, MLN-02, MLN0002), PF-00547659 (anti-MAdCAM), Alicaforsen (anti-ICAM-1), and CCX282-B (anti-CCR9, GSK-1605786, Traficet-EN™) and their risks such as PML reported for natalizumab. Hopefully, the newer gut specific drug designs discussed in this article will have an impact on both efficacy and safety.

Homing of conventional T cells to NALT is primarily dependent on L-selectin–PNAd interactions, whereas homing of regulatory T cells also depends on PSGL1- and CD44-mediated adhesion., Nasal-associated lymphoid tissue (NALT) is a mucosal immune tissue that provides immune responses against inhaled antigens. Lymphocyte homing to NALT is mediated by specific interactions between lymphocytes and high endothelial venules (HEVs) in NALT. In contrast to HEVs in other mucosal lymphoid tissues, NALT HEVs strongly express peripheral node addressins (PNAds) that bear sulfated glycans recognized by the monoclonal antibody MECA-79. We investigated the role of PNAd in lymphocyte homing to NALT using sulfotransferase N-acetylglucosamine-6-O-sulfotransferase (GlcNAc6ST) 1 and GlcNAc6ST-2 double knockout (DKO) mice. The expression of PNAd in NALT HEVs was eliminated in DKO mice. Short-term homing assays indicated that lymphocyte homing to NALT was diminished by 90% in DKO mice. Production of antigen-specific IgE and the number of sneezes in response to nasally administered ovalbumin were also substantially diminished. Consistently, the NALT of DKO mice showed reduced production of IL-4 and increased production of IL-10 together with an increase in CD4+CD25+ regulatory T cells (Treg cells). Compared with the homing of CD4+CD25− conventional T cells, the homing of CD4+CD25+ Treg cells to NALT was less dependent on the L-selectin–PNAd interaction but was partially dependent on PSGL-1 (P-selectin glycoprotein ligand 1) and CD44. These results demonstrate that PNAd is essential for lymphocyte homing to NALT and nasal allergic responses.

Marginal zones (MZs) are architecturally organized for clearance of and rapid response against blood-borne Ags entering the spleen. MZ macrophages (MZMs) and MZ B cells are particularly important in host defense against T-independent pathogens and may be crucial for the prevention of diseases, such as streptococcal pneumonia, that are devastating in older patients. Our objective was to determine whether there are changes in the cellular components of the MZ between old and young mice. Using immunocytochemistry and a blinded scoring system, we observed gross architectural changes in the MZs of old mice, including reduction in the abundance of MZMs surrounding the MZ sinus as well as disruptions in positioning of mucosal addressin cell adhesion molecule 1 (MAdCAM-1)+ sinus lining cells and metallophilic macrophages. Loss of frequency of MZMs was corroborated by flow cytometry. A majority of old mice also showed reduced frequency of MZ B cells, which correlated with decreased abundance of MZM in individual old mice. The spleens of old mice showed less deposition of intravenously injected dextran particles within the MZ, likely because of the decreased frequency in MZMs, because SIGN-R1 expression was not reduced on MZM from old mice. The phagocytic ability of individual MZMs was examined using Staphylococcus aureus bioparticles, and no differences in phagocytosis were found between macrophages from young or old spleens. In summary, an anatomical breakdown of the MZ occurs in advanced age, and a reduction in frequency of MZM may affect the ability of the MZM compartment to clear blood-borne Ags and mount proper T-independent immune responses.

Background and aims Leucocyte migration to gut mucosa, mediated by integrin binding to mucosal addressin cell adhesion molecule (MAdCAM), is a promising target for therapeutic intervention in inflammatory bowel disease. This first-in-human study of a monoclonal antibody to MAdCAM, PF-00547,659, aimed to explore the safety and preliminary efficacy of this gut-specific mechanism in ulcerative colitis. Methods In this randomised, double-blind placebo-controlled study, 80 patients with active ulcerative colitis received single or multiple (three doses, 4-week intervals) doses of PF-00547,659 0.03–10 mg/kg IV / SC, or placebo. Safety was assessed by adverse events, laboratory tests, and immunogenicity. Exploratory efficacy analyses were based on Mayo score and endoscopic responder rates at weeks 4 and 12. Faecal calprotectin was quantified as a measure of disease activity, and the number of α 4 β 7 + lymphocytes was measured to demonstrate drug activity. Results No obvious drug-related side effects were observed in the PF-00547,659 group, while patient numbers, especially those fully exposed, were small. Overall responder/remission rates at 4 and 12 weeks were 52%/13% and 42%/22%, respectively with combined PF-00547,659 doses compared with 32%/11% and 21%/0%, respectively with placebo. Equivalent endoscopic responder rates were 50% and 42% versus 26% and 29%, respectively. Faecal calprotectin levels decreased to a greater extent with PF-00547,659 than placebo (week 4: 63% vs 18%). Despite variability, there was a trend for an increase in α 4 β 7 + lymphocytes in patients receiving PF-00547,659. Conclusions The favourable short-term safety profile and preliminary efficacy findings for PF-00547,659 in this first-in-human study pave the way for further investigation in larger trials, to establish the role of PF-00547,659 in ulcerative colitis treatment. Trial Register No: NCT00928681.

Since 9/11 (11 September 1989) border and borderland studies have come back to the centre of numerous interdisciplinary discussions. Most of these focus on issues of security, hence, also addressin...

The pathophysiology of inflammatory bowel disease involves excessive immune effects of inflammatory cells against gut microbes. In genetically predisposed individuals, these effects are considered to contribute to the initiation and perpetuation of mucosal injury. Oxidative stress is a fundamental tissue-destructive mechanisms that can occur due to the reactive oxygen species and reactive nitrogen metabolites which are released in abundance from numerous inflammatory cells that have extravasated from lymphatics and blood vessels to the lamina propria. This extravasation is mediated by interactions between adhesion molecules including mucosal addressin cell adhesion molecule-1 and vascular cell adhesion molecule-1 on the surface of lymphocytes or neutrophils and their ligands on endothelial cells. Thus, reactive oxygen species and adhesion molecules play an important role in the development of inflammatory bowel disease. The present review focuses on the involvement of oxidative stress and adhesion molecules, in particular mucosal addressin cell adhesion molecule-1, in inflammatory bowel disease.

Background β7 Integrin, a cell adhesion molecule, is present in the form of α4β7 integrin or αEβ7 integrin. α4β7 Integrin is expressed on most leucocytes and is essential for their migration to gut-associated lymphoid tissues by interacting with its primary ligand, mucosal addressin cell adhesion molecule-1, which is preferentially expressed in gut-associated lymphoid tissues. Although the importance of α4β7 integrin in intestinal inflammation has been established, its role in cutaneous inflammation remains to be elucidated. Objective We sought to investigate the role of β7 integrin in cutaneous inflammation. Methods We used a murine contact hypersensitivity model and examined the role of β7 integrin by using β7 integrin–deficient and αE integrin–deficient mice. Results β7 Integrin–deficient mice, not αE integrin–deficient mice, are defective in contact hypersensitivity responses. β7 Integrin deficiency does not affect irritant contact dermatitis. The distribution, migration, and function of antigen presenting cells from β7 integrin–deficient mice are comparable to those from wild-type mice. Moreover, sensitized β7 integrin–deficient T cells are able to respond to antigen stimuli in vitro and elicit contact hypersensitivity responses when directly injected into the skin. However, they are defective in reaching the skin under inflammatory conditions, resulting in reduced contact hypersensitivity responses when intravenously injected. Furthermore, intraperitoneal injection of anti–α4β7 integrin neutralizing antibody elicit impaired contact hypersensitivity responses. Conclusion α4β7 Integrin contributes to contact hypersensitivity responses by regulating T-cell migration to inflammatory skin.

Background: “Candidatus Helicobacter heilmannii” induce chronic gastritis, which eventually leads to gastric B-cell type mucosa-associated lymphoid tissue (MALT) lymphoma. This study was performed using an animal model of infection with “Candidatus Helicobacter heilmannii” to elucidate how this chronic inflammation is induced or maintained. Materials and Methods: BALB/c mice were infected with the “Candidatus Helicobacter heilmannii” isolate SH4. The animals were examined at 8, 26, 54, and 83 weeks after the infection. The stomach of the animals was resected and immunostained for peripheral lymph node addressin (PNAd) and mucosal addressin cell adhesion molecule 1 (MAdCAM-1), “Candidatus Helicobacter heilmannii,” and CD45R/B220. An in vitro binding assay with L- and E-selectin·IgM chimeric proteins was performed. Real-time polymerase chain reaction was used to evaluate transcripts of N-acetylglucosamine-6-O-sulfotransferases (GlcNAc6STs), which direct the expression of the PNAd and MAdCAM-1. Results: Chronic gastritis developed in the infected animals, and its severity increased with the duration of the infection. B-cell type MALT lymphoma developed in some animals at 54 and 83 weeks after infection. PNAd- and MAdCAM-1-expressing high endothelial venule (HEV)-like vessels were induced in infected animals which developed chronic gastritis and MALT lymphoma. The number of HEV-like vessels increased as chronic inflammation progressed. The induced HEV-like vessels were bound by L- and E-selectin·IgM chimeric protein. mRNA expressions of GlcNAc6ST-1 and MAdCAM-1 increased in the infected animals. Conclusions: HEV-like vessels expressing GlcNAc6ST-1-mediated L-selectin ligand carbohydrate and MAdCAM-1 may play a crucial role in the pathogenesis of “Candidatus Helicobacter heilmannii”-induced chronic gastritis and MALT lymphoma.

Integrins are dimeric cell surface molecules composed of α and β subunits that promote cell–cell interactions and play important roles in the immune system. Within the integrin family, α4β7 displays relative specificity for the mucosal immunity and has multiple functions including lymphocyte homing, intestinal lymphoid tissue formation, and promoting inflammatory responses.1–6 Blockade of α4β7 is an appealing therapy for intestinal inflammatory diseases, as the effects of blocking this pathway will largely be limited to mucosal sites. While diverse functions for α4β7 in intestinal immunity are well described, the essential nature of α4β7 in these roles is less clear, and blockade of these essential functions could result in untoward effects of this therapy including inhibiting the homing of nonpathogenic lymphocytes and the formation of homeostatic lymphoid tissues. Mucosal vascular addressin cell adhesion molecule (MAdCAM-1) is the binding partner for α4β7,1 and is expressed on high endothelial venules (HEVs) and postcapillary vessels in the intestine. In contrast, α4β7 is expressed by diverse populations of hematopoietic cells including lymphocytes, natural killer cells, monocytes, and lymphoid tissue inducer (LTi) cells.5–9 A role for α4β7/ MadCAM-1 interactions in lymphocyte trafficking to the intestine is widely accepted; however, the lymphocyte subsets, cellular compartments, and conditions in which α4β7 plays an essential role, and therefore would be affected by α4β7 blockade, are less clear. Early studies using adoptive transfer of labeled lymphocytes identified a role for α4β7 in lymphocyte homing to Peyer’s patches and mucosa in the uninflamed intestine.2 Later studies of using genetically modified mice confirmed that in the absence of β7 in the uninflamed intestine, Peyer’s patches had diminished cellularity and mucosal lymphocyte populations were decreased.10 However, these studies were performed prior to the appreciation of the diversity of lymphocyte subsets, and consequently information regarding the essential nature of α4β7 for homing of specific lymphocyte populations in the uninflamed intestine is largely lacking. Moreover, blockade of the α4β7/MadCAM-1 pathway has had variable effectiveness in animal models of intestinal inflammation,3,11–14 which could be explained by differences in the specificity of the blockade strategy, or the homing mechanisms used by lymphocyte subpopulations playing a pathogenic or protective role in each model. In addition to the above effects, α4β7 blockade may affect the development of intestinal lymphoid tissues during inflammation. α4β7/MadCAM-1 interactions play a critical role in the development of isolated lymphoid follicles (ILFs),6 or intestinal lymphoid aggregates, in the uninflamed adult intestine. During pathogenic inflammatory diseases, including inflammatory bowel disease (IBD), increased numbers of lymphoid aggregates are also seen,15–18 and the above observations suggest that their development may also be dependent on α4β7/MadCAM-1 interactions. During physiologic inflammation, ILFs mediate homeostatic functions in intestinal immunity; conversely, the function of lymphoid aggregates during chronic intestinal inflammation is less clear and may be pathogenic, as these lymphoid aggregates have been proposed to be the sites containing the earliest manifestations of IBD.19,20 Thus, α4β7 blockade could affect lymphoid aggregate development during uncontrolled intestinal inflammation, resulting in either detrimental or beneficial effects. In order to better understand the processes lost in the absence of α4β7 function we investigated the effect of α4β7 blockade and β7 deficiency on lymphoid tissue development and lymphocyte subpopulations in the uninflamed and inflamed intestine. In contrast to current perceptions, we observed that T-lymphocyte populations in the diffuse lamina propria and lymphoid aggregates were unaffected in the absence of α4β7 function in normal mice and in the acute injury dextran sodium sulfate (DSS) colitis model. Concordant with prior observations we observed that lamina propria B-lymphocyte populations and the development of B-lymphocyte containing lymphoid aggregates were both affected by loss of α4β7 function in the normal intestine and in the acute injury DSS colitis model. Furthermore, we observed that Foxp3+ T-lymphocytes, like B-lymphocytes, were dependent on α4β7 function to localize to lymphoid aggregates. In contrast to the above observations, T-lymphocyte trafficking in T-lymphocyte-mediated colitis model was dependent on α4β7 function. Anti-α4β7 blockade did not alter intestinal T-lymphocyte populations or ameliorate acute injury DSS-induced colitis, but did improve chronic T-lymphocyte-mediated colitis as evidenced by decreased T-lymphocyte infiltration into the intestine and decreased production of inflammatory cyto-kines. These observations demonstrate differential dependence on α4β7 by intestinal lymphocyte subpopulations and suggest that α4β7 blockade may be a more targeted therapy than previously appreciated by selectively blocking T-lymphocyte trafficking to the intestine during chronic T-lymphocyte-mediated inflammation.

Objective: In this study, three-dimensional (3D) structures of lung cancer cell line proteins (cellular tumor antigen [p53], caspase 3, and mucosal addressin cell adhesion molecule 1) were generated, and their binding affinities with apigenin through local docking were studied.Methods: The lung cancer cell line proteins were built using Swiss model and visualized by the PyMol software. The physicochemical characterization of the protein models was evaluated by Expasy’s ProtParam Proteomics server. Then, they were validated by PROCHECK, ProQ, ERRAT, and Verify 3D programs. Finally, the protein models were docked with apigenin using BSP-Slim server.Results: All the protein models were acceptable and of good quality. The apigenin showed the binding energy with cellular tumor antigen (p53), caspase 3, and mucosal addressin cell adhesion molecule 1 at −4.611, −5.750, and −5.307 kcal/mol, respectively.Conclusion: The caspase 3 had the strongest bond with apigenin. These potential drug candidates can further be validated in laboratory experiments for its proper function.

Mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) is an important target in the treatment of inflammatory bowel disease (IBD). Recently, treatment of IBD with an antibody to alpha4beta7-integrin, a ligand for MAdCAM-1, has been an intense focus of research. Our aim was to clarify the mechanism by which MAdCAM-1 is regulated via angiotensin II type 1 receptor (AT1R), and to verify if AT1R might be a novel target for IBD treatment. The role of AT1R in the expression of MAdCAM-1 in SVEC (a murine high endothelial venule cell) and MJC-1 (a mouse colonic endothelial cell) was examined following cytokine stimulation. We further evaluated the effect of AT1R on the pathogenesis of immune-mediated colitis using AT1R-deficient (AT1R-/-) mice and a selective AT1R blocker. AT1R blocker significantly suppressed MAdCAM-1 expression induced by TNF-alpha, but did not inhibit phosphorylation of p38 MAPK or of IkappaB that modulate MAdCAM-1 expression. However, NF-kappaB translocation into the nucleus was inhibited by these treatments. In a murine colitis model induced by dextran sulfate sodium, the degree of colitis, judged by body weight loss, histological damage, and the disease activity index, was much milder in AT1R-/- than in wild-type mice. The expression of MAdCAM-1 was also significantly lower in AT1R-/- than in wild-type mice. These results suggest that AT1R regulates the expression of MAdCAM-1 under colonic inflammatory conditions through regulation of the translocation of NF-kappaB into the nucleus. Furthermore, inhibition of AT1R ameliorates colitis in a mouse colitis model. Therefore, AT1R might be one of new therapeutic target of IBD via regulation of MAdCAM-1.

Lymphocytes involved in intestinal immune response are found in organized immune inductive sites of the gut-associated lymphoid tissues (GALT) such as Peyer's patches (PP), mesenteric lymph nodes (MLN) and diffuse effector sites of gut epithelium and lamina propria (LP). beta(7) integrins are responsible for efficient trafficking and retention of lymphocytes in these sites. Naive and effector lymphocytes use alpha(4)beta(7) integrin to extravasate from blood to gut mucosal tissues of GALT, MLN and LP via interactions with Mucosal Addressin Cell Adhesion Molecule-1 (MAdCAM-1). The alpha(E)beta(7) integrin facilitates retention of effector and memory lymphocytes in the gut epithelial layer via interactions with E-cadherin. Mucosal dendritic cells (DCs) regulate the expression of the gut homing receptors alpha(4)beta(7) integrin and the chemokine receptor CCR9 on activated effector and regulatory lymphocytes in a retinoic acid-dependent manner. CD103 (alpha(E) integrin) identifies a subset of mucosal DCs in MLN and small intestine LP that have an enhanced ability to induce gut-tropic receptors on responding lymphocytes. The interactions between beta(7) integrin and their ligands are also implicated in the pathogenesis and progression of inflammatory bowel diseases (IBDs), intestinal parasitic infections and graft-versus-host diseases. During intestinal inflammation, beta(7) integrin-dependent and -independent pathways contribute to lymphocytes recruitment to the intestinal tissues and disease pat-hogenesis. Recent works have explored the potential of therapeutic targeting of alpha(4) and beta(7) integrins in IBDs. Here, we review the current understanding of the role of beta(7) integrins in intestinal lymphocyte trafficking and retention in health and disease.