Bioassay detects soluble MAdCAM-1 in body fluids

MAdCAM-1 co-stimulation combined with retinoic acid and TGF-β induces blood CD8+ T cells to adopt a gut CD101+ TRM phenotype

Resident memory T cells (TRMs) help control local immune homeostasis and contribute to tissue-protective immune responses. The local cues that guide their differentiation and localization are poorly defined. We demonstrate that mucosal vascular addressin cell adhesion molecule 1, a ligand for the gut-homing receptor α4β7 integrin, in the presence of retinoic acid and transforming growth factor-β (TGF-β) provides a co-stimulatory signal that induces blood cluster of differentiation (CD8+ T cells to adopt a TRM-like phenotype. These cells express CD103 (integrin αE) and CD69, the two major TRM cell-surface markers, along with CD101. They also express C-C motif chemokine receptors 5 (CCR5) , C-C motif chemokine receptors 9 (CCR9), and α4β7, three receptors associated with gut homing. A subset also expresses E-cadherin, a ligand for αEβ7. Fluorescent lifetime imaging indicated an αEβ7 and E-cadherin cis interaction on the plasma membrane. This report advances our understanding of the signals that drive the differentiation of CD8+ T cells into resident memory T cells and provides a means to expand these cells in vitro, thereby affording an avenue to generate more effective tissue-specific immunotherapies.

MAdCAM-1 costimulation in the presence of retinoic acid and TGF-β promotes HIV infection and differentiation of CD4+ T cells into CCR5+ TRM-like cells

CD4+ tissue resident memory T cells (TRMs) are implicated in the formation of persistent HIV reservoirs that are established during the very early stages of infection. The tissue-specific factors that direct T cells to establish tissue residency are not well defined, nor are the factors that establish viral latency. We report that costimulation via MAdCAM-1 and retinoic acid (RA), two constituents of gut tissues, together with TGF-β, promote the differentiation of CD4+ T cells into a distinct subset α4β7+CD69+CD103+ TRM-like cells. Among the costimulatory ligands we evaluated, MAdCAM-1 was unique in its capacity to upregulate both CCR5 and CCR9. MAdCAM-1 costimulation rendered cells susceptible to HIV infection. Differentiation of TRM-like cells was reduced by MAdCAM-1 antagonists developed to treat inflammatory bowel diseases. These finding provide a framework to better understand the contribution of CD4+ TRMs to persistent viral reservoirs and HIV pathogenesis.

Urinary complement proteins in IgA nephropathy progression from a relative quantitative proteomic analysis

Aim

IgA nephropathy (IgAN) is one of the leading causes of end-stage renal disease (ESRD). Urine testing is a non-invasive way to track the biomarkers used for measuring renal injury. This study aimed to analyse urinary complement proteins during IgAN progression using quantitative proteomics.

Methods

In the discovery phase, we analysed 22 IgAN patients who were divided into three groups (IgAN 1-3) according to their estimated glomerular filtration rate (eGFR). Eight patients with primary membranous nephropathy (pMN) were used as controls. Isobaric tags for relative and absolute quantitation (iTRAQ) labelling, coupled with liquid chromatography-tandem mass spectrometry, was used to analyse global urinary protein expression. In the validation phase, western blotting and parallel reaction monitoring (PRM) were used to verify the iTRAQ results in an independent cohort (N = 64).

Results

In the discovery phase, 747 proteins were identified in the urine of IgAN and pMN patients. There were different urine protein profiles in IgAN and pMN patients, and the bioinformatics analysis revealed that the complement and coagulation pathways were most activated. We identified a total of 27 urinary complement proteins related to IgAN. The relative abundance of C3, the membrane attack complex (MAC), the complement regulatory proteins of the alternative pathway (AP), and MBL (mannose-binding lectin) and MASP1 (MBL associated serine protease 2) in the lectin pathway (LP) increased during IgAN progression. This was especially true for MAC, which was found to be involved prominently in disease progression. Alpha-N-acetylglucosaminidase (NAGLU) and α-galactosidase A (GLA) were validated by western blot and the results were consistent with the iTRAQ results. Ten proteins were validated in a PRM analysis, and these results were also consistent with the iTRAQ results. Complement factor B (CFB) and complement component C8 alpha chain (C8A) both increased with the progression of IgAN. The combination of CFB and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) also showed potential as a urinary biomarker for monitoring IgAN development.

Conclusion

There were abundant complement components in the urine of IgAN patients, indicating that the activation of AP and LP is involved in IgAN progression. Urinary complement proteins may be used as biomarkers for evaluating IgAN progression in the future.

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

Simple Summary

Psoriasis and lichen planus are common skin diseases which have similar clinical presentation and pathogenesis. Considering these dermatoses are frequent and decrease patients’ life quality, it is important to look for different markers indicating patients’ condition which can possibly affect the choice of the treatment. MAdCAM-1 and ITGB7 molecules and their serum levels in patients with psoriasis and lichen planus have never been studied before; therefore, we are the first trying to analyze it in order to develop the current state of knowledge on psoriasis and lichen planus to better help patients.

Abstract

Plaque psoriasis (PSO) and lichen planus (LP) are skin diseases with some similarities in pathogenesis, comorbidities, and clinical presentation. Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) and its ligand, α₄β₇ integrin, are involved in inflammatory bowel diseases and liver dysfunctions, which occur more frequently in PSO and LP. Serum MAdCAM-1 and ITGB7 levels in patients with plaque PSO and eruptive LP have never been studied before. The study included 42 patients with PSO, 13 with LP, and 23 controls. Serum molecules levels were evaluated using the immune–enzymatic method. ITGB7 concentration was not statistically different, both in patients with PSO and LP, compared to controls (both p > 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.

Tissue Exposure does not Explain Non-Response in Ulcerative Colitis Patients with Adequate Serum Vedolizumab Concentrations

BACKGROUND AND AIMS

Some patients with ulcerative colitis [UC] do not respond to vedolizumab treatment despite adequate drug exposure in serum. This study aimed to investigate vedolizumab in tissue and questioned whether insufficient tissue exposure could explain non-response in UC patients with adequate serum vedolizumab concentrations.

METHODS

A paired serum sample and colonic mucosal biopsy was collected from 40 UC patients [20 endoscopic responders, 20 non-responders] at week 14 of vedolizumab treatment. Vedolizumab, soluble [s]-mucosal addressin cell adhesion molecule-1 [MAdCAM-1], s-vascular cell adhesion molecule-1 [VCAM-1] and s-intercellular adhesion molecule-1 [ICAM-1] were measured in serum and/or tissue. Endoscopic response was defined as Mayo endoscopic sub-score ≤1.

RESULTS

A significant positive correlation was observed between vedolizumab serum and colonic tissue concentrations [ρ = 0.84, p < 0.0001], regardless of the macroscopic inflammatory state of the tissue. Vedolizumab tissue concentrations were lower in non-responders than in responders [0.07 vs 0.11 µg/mg, p = 0.04]. In the subgroup of patients with adequate vedolizumab serum concentrations [>14.6 µg/mL], tissue vedolizumab was not significantly different between responders and non-responders [0.15 vs 0.13 µg/mg; p = 0.92]. Serum sMAdCAM-1 concentrations, but not serum sICAM-1 or sVCAM-1 concentrations, were significantly higher in responders than in non-responders with adequate vedolizumab serum concentrations [1.04 vs 0.83 ng/mL, p = 0.03].

CONCLUSIONS

Vedolizumab concentrations in colonic mucosal tissue of UC patients reflect the concentration in serum regardless of the macroscopic inflammatory state of the tissue. Our data show that insufficient tissue exposure does not explain non-response in UC patients with adequate serum vedolizumab concentrations.

Early urine proteome changes in an implanted bone cancer rat model

In this study, Walker 256 cells were implanted into rat tibiae. Urine samples were then collected on days 3, 5, 7, and 13 and were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). With label-free quantification, 25 proteins were found to change significantly in the urine of the tumor group rats compared with the proteins in the urine of the control group rats; this was even the case when there were no significant lesions identified in the Computed Tomography (CT) examination. Among these differentially proteins, 7 were reported to be associated with tumor bone metastasis. GO analysis shows that the differential proteins on day 3 were involved in several responses, including the acute phase response, the adaptive immune response and the innate immune response. The differentially proteins on day 7 were involved in the mineral absorption pathway. The differentially proteins on day 13 were involved in vitamin D binding and calcium ion binding. These processes may be associated with bone metastasis. Our results demonstrate that urine could sensitively reflect the changes in the early stage of implanted bone cancer; this provides valuable clues for future studies of urine biomarkers for tumor bone metastasis.

A product review of vedolizumab in inflammatory bowel disease

Vedolizumab is a monoclonal antibody to the α4β7 integrin that selectively reduces intestinal lymphocyte trafficking, thereby providing a safe and effective treatment option for patients with inflammatory bowel disease (IBD). This product review outlines the unique mechanism of vedolizumab in addition to efficacy, safety, pharmacokinetic and pharmacodynamic data from clinical trials, observational studies and meta-analyses. Vedolizumab has been shown to be effective as a first- or second-line induction and maintenance therapy in both ulcerative colitis (UC) and Crohn's disease (CD). Prolonged induction therapy may increase efficacy, particularly in tumor necrosis factor-alpha-exposed CD patients. To date, no drug-specific safety signals have been identified. In addition to the presence of an apparent exposure-response relationship, vedolizumab has demonstrated consistent pharmacodynamic effects on α4β7, mucosal vascular addressin cell adhesion molecule 1 and other cell adhesion molecules. Future efforts should focus on identifying predictive biomarkers capable of guiding personalized IBD treatment with vedolizumab.

Biomarkers Are Associated With Clinical and Endoscopic Outcomes With Vedolizumab Treatment in Ulcerative Colitis

Background

Vedolizumab inhibits α4β7-mediated lymphocyte trafficking and is effective in ulcerative colitis (UC). This study evaluated drug and biomarker concentrations and patient outcomes during vedolizumab treatment in UC.

Methods

Prospectively scored maintenance clinical (26.5 weeks; interquartile range [IQR], 16.3-37.0 weeks) and endoscopic (23.5 weeks; IQR, 16.8-35.6 weeks) outcomes were compared with serum vedolizumab concentrations, antivedolizumab antibodies, and serum biomarkers at baseline and weeks 2, 6, 14, and 26. A linear mixed-effects model compared biomarker trajectories over time between clinical and endoscopic remitters and nonremitters.

Results

Thirty-two patients were included. Soluble (s)-tumor necrosis factor (TNF)-α, s-α4β7, s-mucosal addressin cell adhesion molecule (s-MAdCAM-1), and s-amyloid A (s-AA) significantly changed with treatment. A linear mixed-effects model demonstrated that s-α4β7 (P = 0.044) increased and s-MAdCAM-1 (P = 0.006) and s-vascular cell adhesion molecule-1 (s-VCAM-1, P = 0.001) decreased more rapidly in patients achieving clinical remission in maintenance. S-MAdCAM-1 (P = 0.005), s-intracellular adhesion molecule-1 (ICAM-1; P = 0.014), s-VCAM-1 (P < 0.001), and s-TNF (P = 0.052) decreased more rapidly in endoscopic remitters. In clinical remitters, higher week 14 (20.3 ng/mL vs 6.0 ng/mL; P = 0.013) and week 26 (14.1 ng/mL vs 8.6 ng/mL; P = 0.05) s-α4β7 were observed. In endoscopic remitters, week 2 (6.7 pg/mL vs 17.8 pg/mL; P = 0.038) and week 6 (3.9 pg/mL vs 15.6 pg/mL; P = 0.005) s-TNF and week 14 s-VCAM (589.1 ng/mL vs 746.0 ng/mL; P = 0.05) were lower.

Conclusion

Serum biomarkers were associated with outcomes in vedolizumab-treated UC patients. s-α4β7 increased, whereas s-MAdCAM-1, s-VCAM-1, s-ICAM-1, and s-TNF decreased more rapidly in remitters. At individual time points, induction s-TNF and maintenance s-VCAM-1 concentrations were lower, whereas maintenance s-α4β7 concentrations were higher in remitters.

Review article: nonclinical and clinical pharmacology, pharmacokinetics and pharmacodynamics of etrolizumab, an anti-β7 integrin therapy for inflammatory bowel disease

BACKGROUND

Novel treatments with superior benefit-risk profiles are needed to improve the long-term prognosis of patients with inflammatory bowel disease (IBD). Etrolizumab-a monoclonal antibody that specifically targets β7 integrins-is currently under phase III clinical evaluation in IBD.

AIM

This review summarises the available pharmacological and pharmacokinetic/pharmacodynamic data for etrolizumab to provide a comprehensive understanding of its mechanism of action (MOA) and pharmacological effects.

METHODS

Published and internal unpublished data from nonclinical and clinical studies with etrolizumab are reviewed.

RESULTS

Etrolizumab exerts its effect via a unique dual MOA that inhibits both leucocyte trafficking to the intestinal mucosa and retention within the intestinal epithelial layer. The gut-selectivity of etrolizumab results from its specific targeting of the β7 subunit of α4β7 and αEβ7 integrins. Etrolizumab does not bind to α4β1 integrin, which mediates lymphocyte trafficking to tissues including the central nervous system, a characteristic underlying its favourable safety with regard to progressive multifocal leucoencephalopathy. Phase I/II studies in patients with ulcerative colitis (UC) showed linear pharmacokinetics when etrolizumab was administered subcutaneously at 100 mg or higher once every 4 weeks. This dose was sufficient to enable full β7 receptor occupancy in both blood and intestinal tissues of patients with moderate to severe UC. The phase II study results also suggested that patients with elevated intestinal expression of αE integrin may have an increased likelihood of clinical remission in response to etrolizumab treatment.

CONCLUSION

Etrolizumab is a gut-selective, anti-β7 integrin monoclonal antibody that may have therapeutic potential for the treatment of IBD.

Physiologically relevant binding affinity quantification of monoclonal antibody PF-00547659 to mucosal addressin cell adhesion molecule for in vitro in vivo correlation

Background and Purpose

A monoclonal antibody (PF‐00547659) against mucosal addressin cell adhesion molecule (MAdCAM), expressed as both soluble (sMAdCAM) and trans‐membrane (mMAdCAM) target forms, showed over 30‐fold difference in antibody‐target K_D between in vitro (Biacore) and clinically derived (K_D,in‐vivo) values. Back‐scattering interferometry (BSI) was applied to acquire physiologically relevant K_D values which were used to establish in vitro and in vivo correlation (IVIVC).

Experimental Approach

BSI was applied to obtain K_D values between PF‐00547659 and recombinant human MAdCAM in buffer or CHO cells and endogenous MAdCAM in human serum or colon tissue. CHO cells and tissue were minimally processed to yield homogenate containing membrane vesicles and soluble proteins. A series of binding affinities in serum with various dilution factors was used to estimate both K_D,in‐vivo and target concentrations; MAdCAM concentrations were also measured using LC–MS/MS.

Key Results

BSI measurements revealed low K_D values (higher affinity) for sMAdCAM in buffer and serum, yet a 20‐fold higher K_D value (lower affinity) for mMAdCAM in CHO, mMAdCAM and sMAdCAM in tissue. BSI predicted K_D,in‐vivo in serum was similar to clinically derived K_D,in‐vivo, and the BSI‐estimated serum sMAdCAM concentration also matched the measured concentration by LC–MS/MS.

Conclusions and Implications

Our results successfully demonstrated that BSI measurements of physiologically relevant K_D values can be used to establish IVIVC, for PF‐00547659 to MAdCAM despite the lack of correlation when using Biacore measured K_D and accurately estimates endogenous target concentrations. The application of BSI would greatly enhance successful basic pharmacological research and drug development.

Endothelial Fas-Ligand in Inflammatory Bowel Diseases and in Acute Appendicitis

Fas-mediated induction of apoptosis is a major factor in the selection of lymphocytes and downregulation of immunological processes. In the present study, we have assessed endothelial Fas-ligand (FasL) expression in normal human ileum, appendix, and colon, and compared the expression levels with that in inflammatory bowel disease and in acute appendicitis. In a normal appendix, endothelial FasL levels were constant in almost half of the mucosal vessels; but, in the normal ileum and colon, endothelial FasL was practically restricted to areas in close proximity to lymphatic follicles, and was expressed mainly in the submucosal aspect of the follicles in the vessels with high endothelium. In samples from subjects with either Crohn's disease or ulcerative colitis, the extent of endothelial FasL expression was elevated in the submucosa and associated with an elevated number of lymphoid follicles. In inflammatory bowel disease, ulcers and areas with a high density of mononuclear cells expressing FasL also showed an elevated density of blood vessels with endothelial FasL expression. Although the function of endothelial FasL remains unclear, such a specific expression pattern suggests that endothelial FasL expression has a role in the regulation of lymphocyte access to the peripheral lymphoid tissues, including the intestinal mucosa.

Sex hormones selectively impact the endocervical mucosal microenvironment: implications for HIV transmission

Several studies suggest that progesterone and estrogens may affect HIV transmission in different, possibly opposing ways. Nonetheless, a direct comparison of their effects on the mucosal immune system has never been done. We hypothesize that sex hormones might impact the availability of cells and immune factors important in early stages of mucosal transmission, and, in doing so influence the risk of HIV acquisition. To test this hypothesis, we employed 15 ovarectomized rhesus macaques: 5 were treated with Depot Medroxy Progesterone Acetate (DMPA), 6 with 17-β estradiol (E2) and 4 were left untreated. All animals were euthanized 5 weeks after the initiation of hormone treatment, a time post-DMPA injection associated with high susceptibility to SIV infection. We found that DMPA-treated macaques exhibited higher expression of integrin α4β7 (α4β7) on CD4+ T cells, the gut homing receptor and a marker of cells highly susceptible to HIV, in the endocervix than did the E2-treated animals. In contrast, the frequency of CCR5+ CD4+ T cells in DMPA-treated macaques was higher than in the E2-treated group in vaginal tissue, but lower in endocervix. α4β7 expression on dendritic cells (DCs) was higher in the DMPA-treated group in the endocervical tissue, but lower in vaginal tissue and on blood DCs compared with the E2-treated animals. Soluble MAdCAM-1, the α4β7 ligand, was present in the vaginal fluids of the control and E2-treated groups, but absent in the fluids from DMPA-treated animals. Both hormones modulated the expression and release of inflammatory factors and modified the distribution of sialomucins in the endocervix. In summary, we found that sex hormones profoundly impact mucosal immune factors that are directly implicated in HIV transmission. The effect is particularly significant in the endocervix. This may increase our understanding of the potential hormone-driven modulation of HIV susceptibility and potentially guide contraceptive policies in high-risk settings.

Regulation of mucosal addressin cell adhesion molecule 1 expression in human and mice by vascular adhesion protein 1 amine oxidase activity

Primary sclerosing cholangitis (PSC) and autoimmune hepatitis are hepatic complications associated with inflammatory bowel disease (IBD). The expression of mucosal addressin cell adhesion molecule 1 (MAdCAM-1) on mucosal endothelium is a prerequisite for the development of IBD, and it is also detected on the hepatic vessels of patients with liver diseases associated with IBD. This aberrant hepatic expression of MAdCAM-1 results in the recruitment of effector cells initially activated in the gut to the liver, in which they drive liver injury. However, the factors responsible for the aberrant hepatic expression of MAdCAM-1 are not known. In this study, we show that deamination of methylamine (MA) by vascular adhesion protein 1 (VAP-1) [a semicarbazide-sensitive amine oxidase (SSAO) expressed in the human liver] in the presence of tumor necrosis factor α induces the expression of functional MAdCAM-1 in hepatic endothelial cells and in intact human liver tissue ex vivo. This is associated with increased adhesion of lymphocytes from patients with PSC to hepatic vessels. Feeding mice MA, a constituent of food and cigarette smoke found in portal blood, led to VAP-1/SSAO-dependent MAdCAM-1 expression in mucosal vessels in vivo.

CONCLUSION

Activation of VAP-1/SSAO enzymatic activity by MA, a constituent of food and cigarette smoke, induces the expression of MAdCAM-1 in hepatic vessels and results in the enhanced recruitment of mucosal effector lymphocytes to the liver. This could be an important mechanism underlying the hepatic complications of IBD.

CNS elevation of vascular and not mucosal addressin cell adhesion molecules in patients with multiple sclerosis

The mucosal addressin cell adhesion molecule (MAdCAM) and vascular cell adhesion molecule (VCAM) appear to play roles in the recruitment of leukocytes to specialized endothelium lining the gastrointestinal tract. The purpose of this study was to clarify the role of MAdCAM and VCAM in the central nervous system by comparing protein expression in patients with multiple sclerosis (MS) and control subjects by immunohistochemistry. Specific antibodies to human VCAM and MAdCAM were used to confirm expression in control and MS nervous system specimens by immunohistochemistry. VCAM immunoreactivity was detected in endothelial cells, perivascular tissue, and in some cases, leukocytes within the meninges, gray, and white matter, of both controls and MS patients. VCAM immunoreactivity was maximal in a patient with acute active plaques, but of lower intensity and reduced distribution in controls and those with chronic active or inactive MS plaques. In contrast, MAdCAM immunoreactivity could not be detected in brain tissue from unaffected or MS patients. Taken together, these data support a role of VCAM, but not MAdCAM in the development of MS.