Anti-integrin Antibodies Research Articles

Anti-integrin αvβ6 antibody titer as a predictive biomarker of future treatment escalation in patients with ulcerative colitis

Anti-integrin αvβ6 antibody titer as a predictive biomarker of future treatment escalation in patients with ulcerative colitis

Bone sialoprotein stimulates cancer cell adhesion through the RGD motif and the αvβ3 and αvβ5 integrin receptors.

Being implicated in bone metastasis development, bone sialoprotein (BSP) expression is upregulated in patients with cancer. While BSP regulates cancer cell adhesion to the extracellular matrix, to the best of our knowledge, the specific adhesive molecular interactions in metastatic bone disease remain unclear. The present study aimed to improve the understanding of the arginine-glycine-aspartic acid (RGD) sequence of BSP and the integrin receptors αvβ3 and αvβ5 in BSP-mediated cancer cell adhesion. Human breast cancer (MDA-MB-231), prostate cancer (PC-3) and non-small cell lung cancer (NSCLC; NCI-H460) cell lines were cultured on BSP-coated plates. Adhesion assays with varying BSP concentrations were performed to evaluate the effect of exogenous glycine-arginine-glycine-aspartic acid-serine-proline (GRGDSP) peptide and anti-integrin antibodies on the attachment of cancer cells to BSP. Cell attachment was assessed using the alamarBlue® assay. The present results indicated that BSP supported the adhesion of cancer cells. The RGD counterpart GRGDSP peptide reduced the attachment of all tested cancer cell lines to BSP by ≤98.4%. Experiments with anti-integrin antibodies demonstrated differences among integrin receptors and cancer cell types. The αvβ5 antibody decreased NSCLC cell adhesion to BSP by 84.3%, while the αvβ3 antibody decreased adhesion by 14%. The αvβ3 antibody decreased PC-3 cell adhesion to BSP by 46.4%, while the αvβ5 antibody decreased adhesion by 9.5%. Adhesion of MDA-MB-231 cells to BSP was inhibited by 54.7% with αvβ5 antibody. The present results demonstrated that BSP-induced cancer cell adhesion occurs through the binding of the RGD sequence of BSP to the cell integrin receptors αvβ3 and αvβ5. Differences between cancer types were found regarding the mediation via αvβ3 or αvβ5 receptors. The present findings may explain why certain cancer cells preferentially spread to the bone tissue, suggesting that targeting the RGD-integrin binding interaction could be a promising novel cancer treatment option.

The Proangiogenic Effects of Melanoma-Derived Ectosomes Are Mediated by αvβ5 Integrin Rather than αvβ3 Integrin.

Ectosomes are carriers of proangiogenic factors during cancer progression. This study investigated whether the proangiogenic effect exerted by melanoma-derived ectosomes on recipient endothelial cells is mediated by ectosomal αvβ3 and αvβ5 integrins. Ectosomes were isolated from the conditioned culture media of four melanoma cell lines and melanocytes. Changes in gene and protein expression of αvβ3 and αvβ5 integrins, as well as VEGF and TNF-α were assessed in ectosome-treated endothelial cells. To confirm the functional involvement of ectosomal integrins in functional tests (Alamar Blue, wound healing and tube formation assays), ectosomes were also pretreated with anti-integrin antibodies and integrin-blocking peptides echistatin and cilengitide. Melanoma-derived ectosomes induced changes in the expression of αvβ3 and αvβ5 integrins in recipient endothelial cells, leading to increased viability, migratory properties, and tube formation potential. The extent of proangiogenic stimulation varied depending on the types of cells releasing ectosomes and the recipient cells. The use of anti-integrin antibodies and integrin-blocking peptides revealed a more significant role for the αvβ5 integrin/VEGF than the αvβ3 integrin/TNF-α pathway in the interactions between ectosomes and endothelial cells. The study demonstrated the functional role of ectosomal αvβ3 and αvβ5 integrins. It also provided a baseline understanding of ectosome-mediated αvβ3 integrin/TNF-α and αvβ5 integrin/VEGF signaling in angiogenesis.

Progesterone modulates cell growth via integrin αvβ3-dependent pathway in progesterone receptor-negative MDA-MB-231 cells

Progesterone (P4) plays a pivotal role in regulating the cancer progression of various types, including breast cancer, primarily through its interaction with the P4 receptor (PR). In PR-negative breast cancer cells, P4 appears to function in mediating cancer progression, such as cell growth. However, the mechanisms underlying the roles of P4 in PR-negative breast cancer cells remain incompletely understood. This study aimed to investigate the effects of P4 on cell proliferation, gene expression, and signal transduction in PR-negative MDA-MB-231 breast cancer cells. P4-activated genes, associated with proliferation in breast cancer cells, exhibit a stimulating effect on cell growth in PR-negative MDA-MB-231 cells, while demonstrating an inhibitory impact in PR-positive MCF-7 cells. The use of arginine-glycine-aspartate (RGD) peptide successfully blocked P4-induced extracellular signal-regulated kinase 1/2 (ERK1/2) activation, aligning with computational models of P4 binding to integrin αvβ3. Disrupting integrin αvβ3 binding with RGD peptide or anti-integrin αvβ3 antibody altered P4-induced expression of proliferative genes and modified P4-induced cell growth in breast cancer cells. In conclusion, integrin αvβ3 appears to mediate P4-induced ERK1/2 signal pathway to regulate proliferation via alteration of proliferation-related gene expression in PR-negative breast cancer cells.

Anti-integrin αvβ6 antibody in Takayasu arteritis patients with or without ulcerative colitis.

It has been well documented that Takayasu arteritis (TAK) and ulcerative colitis (UC) coexist in the same patients. HLA-B*52 characterizes the co-occurrence, which is one of the common genetic features between these two diseases, indicating shared underlying pathologic mechanisms. Anti-integrin αvβ6 antibody (Ab) is present in sera of UC patients in a highly specific manner. We investigated if there were any associations between anti-integrin αvβ6 Ab and TAK, considering the risk HLA alleles. A total of 227 Japanese TAK patients were recruited in the current study and their serum samples were subjected to measurement of anti-integrin αvβ6 Ab by ELISA. The clinical information, including the co-occurrence of UC, was collected. The HLA allele carrier status was determined by Luminex or genotype imputation. The information about the presence of UC was available for 165 patients, among which eight (4.84%) patients had UC. Anti-integrin αvβ6 antibody was identified in 7 out of 8 TAK subjects with UC (87.5%) while only 5 out of 157 (3.18%) TAK subjects without UC had the antibody (OR 121, p=7.46×10-8). A total of 99 out of 218 (45.4%) patients were HLA-B*52 carriers. There was no significant association between the presence of anti-integrin αvβ6 Ab and HLA-B*52 carrier status in those without UC (OR 2.01, 95% CI 0.33-12.4, p = 0.189). The prevalence of anti-integrin αvβ6 Ab was high in TAK patients with UC, but not in the absence of concomitant UC. The effect of HLA-B*52 on anti-integrin αvβ6 Ab production would be minimal.

Single-cell and spatial multi-omics highlight effects of anti-integrin therapy across cellular compartments in ulcerative colitis

Ulcerative colitis (UC) is driven by immune and stromal subsets, culminating in epithelial injury. Vedolizumab (VDZ) is an anti-integrin antibody that is effective for treating UC. VDZ is known to inhibit lymphocyte trafficking to the intestine, but its broader effects on other cell subsets are less defined. To identify the inflammatory cells that contribute to colitis and are affected by VDZ, we perform single-cell transcriptomic and proteomic analyses of peripheral blood and colonic biopsies in healthy controls and patients with UC on VDZ or other therapies. Here we show that VDZ treatment is associated with alterations in circulating and tissue mononuclear phagocyte (MNP) subsets, along with modest shifts in lymphocytes. Spatial multi-omics of formalin-fixed biopsies demonstrates trends towards increased abundance and proximity of MNP and fibroblast subsets in active colitis. Spatial transcriptomics of archived specimens pre-treatment identifies epithelial-, MNP-, and fibroblast-enriched genes related to VDZ responsiveness, highlighting important roles for these subsets in UC.

P502 Multimodal profiling of peripheral blood identifies proliferating circulating effector CD4 T cells as predictors for response to integrin alpha4 beta7-blocking therapy in patients with Inflammatory Bowel Disease

Abstract Background Despite the success of biological therapies in inflammatory bowel disease (IBD), patient management remains challenging due to a lack of therapy response predictors. Methods Here we prospectively sampled two cohorts of IBD patient cohorts receiving the anti-integrin α4β7 antibody vedolizumab. Samples were subjected to mass cytometry, single-cell RNA sequencing, single-cell V(D)J sequencing, serum proteomics, and multidimensional flow cytometry to comprehensively assess vedolizumab-induced immunological changes in the peripheral blood and their potential associations with treatment response. Results Vedolizumab induced changes in the abundance of both circulating innate and adaptive immune cell compartments and modified the T cell receptor diversity of circulating gut-homing CD4+ memory T cells. Through integration of multimodal parameters and machine learning, we identify that pretreatment activated proliferating CD4+ memory T cell abundance is associated with treatment failure, independent of clinical variables, thereby providing a reliable predictive classifier with significant implications for the personalized management of IBD patients. Conclusion Our study provides a comprehensive framework for assessing therapy response and understanding the mechanisms underlying resistance in chronic immune-mediated inflammatory diseases such as IBD. Identifying personalized treatment strategies based on individual patient characteristics, as exemplified by our "stratify to target" approach, can significantly improve IBD management.

P527 Factors associated with choice of treatment regimen after the induction period in patients with Ulcerative Colitis treated with vedolizumab

Abstract Background Vedolizumab (VDZ) is a selective, alpha4-beta7 anti-integrin antibody used for treatment of inflammatory bowel diseases. The aim of our study was to investigate factors that influence the decision making and determine further therapeutic regimen after the induction period in patients with ulcerative colitis treated with VDZ and to identify predictors for early response to VDZ. Methods A retrospective study conducted at the Clinic for gastroenterohepatology, University Clinical Center Serbia included 89 patients with ulcerative colitis (mean age 47±15; 45 males) treated with VDZ (69 bio-naïve and 20 previously exposed to anti-TNF). Localization of disease, endoscopic score at the beginning of therapy, together with CRP and fecal calprotectin levels before the initiation of therapy and at week 14, and prior exposure to anti-TNF in relation to the treatment regimen at the end of the induction period were analyzed. Results After induction therapy total of 55 patients (61.8%) continued with standard dosing regimen, while in 34 patients (38.2%) shortening the interval to 4 weeks as optimization of VDZ treatment was prescribed. Patients whose treatment regimen was optimized at week 14 had had statistically significantly higher baseline CRP levels (p=0.025), as well as CRP levels at week 14 (p=0.002) and fecal calprotectin at week 14 (p=0.000), while there was no difference in the baseline fecal calprotectin between patients in standard and optimized regimen (p=1.000). There was no statistical difference in localization of disease and prior anti-TNF exposure between these two groups of patients (p=0.732 and p=0.449, respectively). Conclusion Higher CRP and fecal calprotectin levels at week 14 were determining factors for optimization of VDZ treatment. Higher levels of CRP before biologic therapy was started was associated with the increased need for optimized regiment at week 14. Extensive disease and prior anti-TNF exposure did not correlate with need for optimization of treatment after the induction period.

A Continuous Registry of Medical Record, Patient Input, and Epidemiological Data of Patients With Ulcerative Colitis: a Multicentre, Prospective, Observational Clinical Registry Study in Japan.

This registry aims to allow for a prospective non-interventional observational study of ulcerative colitis. This will facilitate monitoring of the current state of ulcerative colitis in Japan and improving the long-term disease course and adverse events associated with current treatment options. Inclusion of patients from five centres in Japan is planned. The study is expected to take place from July 15, 2020, to November 30, 2024. Background, demographics, and medical history/information will be collected from electronic medical records at enrolment. Medical information including medications, laboratory data, and disease activity will be collected automatically from electronic medical records throughout the study. Patient-reported quality of life data will be collected directly from patients via smartphone. Efficacy endpoints (clinical remission rate, clinical improvement rate, and endoscopic healing rate) and safety endpoints (incidence of adverse events and specific ulcerative colitis-related events) will be collected according to treatment administered. Treatment categories include no treatment, 5-aminosalicylic acids, corticosteroids, immunomodulators, immunosuppressants, anti-tumour necrosis alpha agents, cytapheresis, Janus kinase inhibitors, anti-integrin antibodies, and anti-interleukin-12/23 antibodies. The dataset will include cross-sectional and longitudinal data and is expected to capture the state of ulcerative colitis in Japan. Patients will be included on a large scale, and the registry will be established automatically from electronic medical records and direct patient input, facilitating the accurate recording of medical information for patients with ulcerative colitis in Japan and minimizing limitations intrinsic to databases that require manual data entry, such as the burden on participating investigators and entry of data with errors/typos.

B-064 Analytical and Diagnostic Performances of Anti-Integrin Antibody System in Inflammatory Bowel Disease

Abstract Background Anti-integrin αvβ6 autoantibodies may have value in the diagnosis of Inflammatory Bowel Disease (IBD) and more specifically Ulcerative Colitis (UC). Our objective was to establish the analytical and diagnostic performance of this novel autoantibody system in distinguishing IBD from a group of Normal Healthy Volunteers (NHV) and UC from Crohn’s Disease (CD). Methods All testing was performed using a Tecan Evo200 equipped with 8-channel and 96-channel arms, plate washer, and plate reader. The ELISA assay used calibration controls and diluted serum samples added to ELISA plates coated with Integrin αvβ6 antigen. Anti-human IgG horseradish peroxidase complexed with Anti-integrin αvβ6 antibodies was detected using colorimetry. The analytical performance was evaluated by using repeatability and reproducibility with coefficient of variation (CV) calculated. The diagnostic performances were evaluated by testing specimens collected from consented subjects available from a biobank in autoimmune gastrointestinal diseases. This consisted of 60 NHV, and 187 IBD (91 CD and 96 UC). Sensitivity, specificity, diagnostic odds ratio (OR), positive and negative predictive values (PPV and NPV) were estimated. Results Intra-assay CVs ranged from 1.5% to 5.2% over dynamic range. Inter-assay CVs were below 10%. Median titers were below 5 U/mL for NHV and CD, and 26 U/mL for UC (Fig. 1). Cutoff of 5 U/mL was 100% specific for UC and CD. Sensitivity for UC and CD was 80% (77/96), and 15% (14/91), respectively. Diagnostic Odds Ratio yielded 22.3-fold (95% CI: 10.5–47.5) higher likelihood of UC than CD in the presence of Anti-integrin αvβ6 titers above cutoff, with PPV and NPV values of 84% (76%-90%) and 81% (74%–87%), respectively (50% pre-test). Conclusion We have established the analytical performance of an Anti-integrin αvβ6 autoantibody ELISA assay. These preliminary data suggests that the Anti-Integrin αvβ6 autoantibody system is highly specific for UC with high sensitivity and specificity.

Diagnostic value of anti-integrin αvβ6 antibodies in ulcerative colitis

Ulcerative colitis (UC)-related mucosal inflammation is characterized by the production of various autoantibodies with limited clinical relevance. Recent studies have shown that circulating levels of IgG against integrin αvβ6 are increased in UC patients as compared to Crohn's disease (CD) patients and healthy controls (HC). The present study assessed the diagnostic value of circulating IgG anti-αvβ6 in UC.Sera were prospectively collected from 108 outpatients with UC, 103 patients with CD, and 62 HC, and the levels of IgG anti-αvβ6 were measured using a commercially available ELISA kit. The cut-off for positive results was defined as the 95th percentile of the values of the autoantibodies in HC serum samples. Levels of IgG anti-αvβ6 were significantly higher in UC than in CD patients, including those with colonic localization, and HC. Fifty-six of the 108 (51.8%) UC patients had a positive test whereas only 17/103 (16.5%) patients with CD, and among these, 4/16 (25%) patients with colonic CD, were positive. In UC, there was no statistical difference between patients with IgG anti-αvβ6 positivity and those negative in terms of clinical disease activity, fecal calprotectin values, and disease extent. The sensitivity, specificity, predictive positive value, and predictive negative value of the test to differentiate between UC and CD were 51.9% (C.I.42.4–61.3), 83.5% (C.I. 76.3–90.7), 76.7% (C.I. 67.0–86.4), and 62.3% (C.I. 54.2–70.4) respectively.Our study confirms that anti-αvβ6 antibodies are demonstrable in the serum of the majority of UC patients and suggests the necessity of further research to understand if the anti-αvβ6 antibody determination could have a place in the clinical decision-making of IBD.

Anti-integrin αvβ6 autoantibodies in patients with primary sclerosing cholangitis.

Patients with primary sclerosing cholangitis (PSC) possess autoantibodies against biliary epithelial cells. However, the target molecules remain unknown. The sera of patients with PSC and controls were subjected to enzyme-linked immunosorbent assays to detect autoantibodies using recombinant integrin proteins. Integrin αvβ6 expression in the bile duct tissues was examined using immunofluorescence. The blocking activity of the autoantibodies was examined using solid-phase binding assays. Anti-integrin αvβ6 antibodies were detected in 49/55 (89.1%) patients with PSC and 5/150 (3.3%) controls (P < 0.001), with a sensitivity and specificity of 89.1% and 96.7%, respectively, for PSC diagnosis. When focusing on the presence or absence of IBD, the proportion of the positive antibodies in PSC with IBD was 97.2% (35/36) and that in PSC alone was 73.7% (14/19) (P = 0.008). Integrin αvβ6 was expressed in bile duct epithelial cells. Immunoglobulin (Ig)G from 15/33 patients with PSC blocked integrin αvβ6-fibronectin binding through an RGD (Arg-Gly-Asp) tripeptide motif. Autoantibodies against integrin αvβ6 were detected in most patients with PSC; anti-integrin αvβ6 antibody may serve as a potential diagnostic biomarker for PSC.

The Underappreciated Role of Secretory IgA in IBD.

Eighty percent of antibody secreting cells (ASCs) are found in the intestine, where they produce grams of immunoglobulin (Ig) A daily. immunoglobulin A is actively transcytosed into the lumen, where it plays a critical role in modulating the gut microbiota. Although loss of immune tolerance to bacterial antigens is the likely trigger of the dysregulated immune response that characterizes inflammatory bowel disease (IBD), little effort has been placed on understanding the interface between B cells, IgA, and the microbiota during initiation or progression of disease. This may be in part due to the misleading fact that IgA-deficient humans are mostly asymptomatic, likely due to redundant role of secretory (S) IgM. Intestinal B cell recruitment is critically dependent on integrin α4β7-MAdCAM-1 interactions, yet antibodies that target α4β7 (ie, vedolizumab), MAdCAM-1 (ie, ontamalimab), or both β7 integrins (α4β7 and αE [CD103] β7; etrolizumab) are in clinical use or development as IBD therapeutics. The effect of such interventions on the biology of IgA is largely unknown, yet a single dose of vedolizumab lowers SIgA levels in stool and weakens the oral immunization response to cholera vaccine in healthy volunteers. Thus, it is critical to further understand the role of these integrins for the migration of ASC and other cellular subsets during homeostasis and IBD-associated inflammation and the mode of action of drugs that interfere with this traffic. We have recently identified a subset of mature ASC that employs integrin αEβ7 to dock with intestinal epithelial cells, predominantly in the pericryptal region of the terminal ileum. This role for the integrin had not been appreciated previously, nor the αEβ7-dependent mechanism of IgA transcytosis that it supports. Furthermore, we find that B cells more than T cells are critically dependent on α4β7-MAdCAM-1 interactions; thus MAdCAM-1 blockade and integrin-β7 deficiency counterintuitively hasten colitis in interleukin-10-deficient mice. In both cases, de novo recruitment of IgA ASC to the intestinal lamina propria is compromised, leading to bacterial overgrowth, dysbiosis, and lethal colitis. Thus, despite the safe and effective use of anti-integrin antibodies in patients with IBD, much remains to be learned about their various cell targets.

OP14 Prevention of postoperative recurrence of Crohn's disease with vedolizumab: First results of the prospective placebo-controlled randomised trial REPREVIO

Abstract Background Crohn’s disease (CD) is a chronic, immune-mediated inflammatory condition of the intestine, for which the majority of patients still needs to undergo surgical resection. Following the most common intervention ileocolonic resection, the vast majority of patients suffers from recurrence of CD in the neoterminal ileum. Endoscopic lesions usually precede symptoms in the first months after resection and predict the severity of the further disease course. No treatments have been approved for recurrence-prevention of CD. REPREVIO is a prospective placebo-controlled randomized trial investigating the preventive effect of vedolizumab, an anti-integrin antibody, on recurrence of CD. Methods Following ileocolonic resection, patients were treated with vedolizumab (300 mg IV at week 0,8,16 and 24) or PLC (1:1) at 12 sites in the Netherlands, France, Italy and Spain. Treatment was initiated within 4 weeks following ileocolonic resection with anastomosis. Six months following surgery, patients underwent ileocolonoscopy for assessment of recurrent lesions. Video recordings were centrally scored using the modified Rutgeerts’ score by 2 readers with adjudication in case of disagreement. The primary endpoint was endoscopic recurrence (ER) of CD (non-parametric); secondary endpoints were the proportion of patients with ER &amp;gt;i2a and clinical recurrence. Adverse events were recorded. Results 95 pts were screened and 80 randomized. All patients have reached month 6 and the videos are being analysed. We will receive the results of all statistical analysis in December, 2022. Conclusion The efficacy of vedolizumab postoperative recurrence-prevention treatment was studied in the REPREVIO study.

Role of Integrins Involved in Mn2+-Dependent Adhesion to Fibronectin Peptide of Mastocytoma P-815 Cells and Peritoneal Mast Cells

Mn2+-dependent integrin-mediated adhesion to the extracellular matrix is extensively studied, however, its implication in mast cell biology remains unexplored. This study aims to investigate the role of Mn2+ in promoting adhesion in mouse mastocytoma P-815 cells (P-815) and peritoneal mast cells (PMC) to the Arg-Gly-Asp (RGD)-enriched fibronectin peptide (RGD matrix) within the culture medium. Our findings indicate that Mn2+ induces cell adhesion, with optimal results achieved when P-815 were exposed to 2 mM Mn2+ for 30 min at 37ºC, resulting in approximately 40% cell adhesion to the RGD matrix. The Mn2+-dependent P-815 adhesion was inhibited by anti-integrin α4, β1, and β3 subunit function-blocking antibodies, and by the integrin αIIbβ3 antagonist tirofiban, indicating the involvement of integrins α4β1 and αIIbβ3. Similarly, Mn2+-dependent PMC adhesion to the RGD matrix was inhibited by anti-integrin α4, α5, β1, β3, and β7 subunit function-blocking antibodies and tirofiban, demonstrating the involvement of integrins α4β1, α4β7, α5β1, and αIIbβ3. Integrins α4β1 and αIIbβ3 were consistently involved in Mn2+-induced adhesion reactions in both P-815 and PMC, while integrins α4β7 and α5β1 were specifically implicated in the response to PMC only. The addition of the actin inhibitor cytochalasin D, glycosylphosphatidylinositol-anchored protein (GPI-AP) cleaving enzyme phosphatidylinositol-specific phospholipase C, and the PKA inhibitor H-89 significantly reduced Mn2+-dependent P-815 adhesion to the RGD matrix. However, adding the myosin II inhibitor brebbistatin and the RhoA inhibitor Y27632 did not produce the same effect. Furthermore, cellular cholesterol removal with 6-O-α-maltosyl-β cyclodextrin significantly diminished Mn2+-dependent P-815 adhesion, concomitant with a decrease in the expression of integrin α4 and β1 subunits on the cell surface.

Structural Requirement of hA5G18 Peptide (DDFVFYVGGYPS) from Laminin α5 Chain for Amyloid-like Fibril Formation and Cell Adhesion.

The hA5G18 peptide (DDFVFYVGGYPS) identified from the human laminin α5 chain G domain promotes cell attachment and spreading when directly coated on a plastic plate, but does not show activity when it is conjugated on a chitosan matrix. Here, we focused on the structural requirement of hA5G18 for activity. hA5G18 was stained with Congo red and formed amyloid-like fibrils. A deletion analysis of hA5G18 revealed that FVFYV was a minimum active sequence for the formation of amyloid-like fibrils, but FVFYV did not promote cell attachment. Next, we designed functional fibrils using FVFYV as a template for amyloid-like fibrils. When we conjugated an integrin binding sequence Arg-Gly-Asp (RGD) to the FVFYV peptide with Gly-Gly (GG) as a spacer, FVFYVGGRGD promoted cell attachment in a plate coat assay, but a negative control sequence RGE conjugated peptide, FVFYVGGRGE, also showed activity. However, when the peptides were conjugated to Sepharose beads, the FVFYVGGRGD beads showed cell attachment activity, but the FVFYVGGRGE beads did not. These results suggest that RGD and RGE similarly contribute to cell attachment activity in amyloid-like fibrils, but only RGD contributes the activity on the Sepharose beads. Further, we conjugated a basic amino acid (Arg, Lys, and His) to the FVFYV peptide. Arg or Lys-conjugated FVFYV peptides, FVFYVGGR and FVFYVGGK, showed cell attachment activity when they were coated on a plate, but a His-conjugated FVFYV peptide FVFYVGGH did not show activity. None of the basic amino acid-conjugated peptides showed cell attachment in a Sepharose bead assay. The cell attachment and spreading on FVFYVGGR and FVFYVGGK were inhibited by an anti-integrin β1 antibody. These results suggest that the Arg and Lys residues play critical roles in the interaction with integrins in amyloid-like fibrils. FVFYV is useful to use as a template for amyloid-like fibrils and to develop multi-functional biomaterials.

An innovative strategy to identify new targets for delivering antibodies to the brain has led to the exploration of the integrin family.

Increasing brain exposure of biotherapeutics is key to success in central nervous system disease drug discovery. Accessing the brain parenchyma is especially difficult for large polar molecules such as biotherapeutics and antibodies because of the blood-brain barrier. We investigated a new immunization strategy to identify novel receptors mediating transcytosis across the blood-brain barrier. We immunized mice with primary non-human primate brain microvascular endothelial cells to obtain antibodies. These antibodies were screened for their capacity to bind and to be internalized by primary non-human primate brain microvascular endothelial cells and Human Cerebral Microvascular Endothelial Cell clone D3. They were further evaluated for their transcytosis capabilities in three in vitro blood-brain barrier models. In parallel, their targets were identified by two different methods and their pattern of binding to human tissue was investigated using immunohistochemistry. 12 antibodies with unique sequence and internalization capacities were selected amongst more than six hundred. Aside from one antibody targeting Activated Leukocyte Cell Adhesion Molecule and one targeting Striatin3, most of the other antibodies recognized β1 integrin and its heterodimers. The antibody with the best transcytosis capabilities in all blood-brain barrier in vitro models and with the best binding capacity was an anti-αnβ1 integrin. In comparison, commercial anti-integrin antibodies performed poorly in transcytosis assays, emphasizing the originality of the antibodies derived here. Immunohistochemistry studies showed specific vascular staining on human and non-human primate tissues. This transcytotic behavior has not previously been reported for anti-integrin antibodies. Further studies should be undertaken to validate this new mechanism in vivo and to evaluate its potential in brain delivery.

Research trends in ulcerative colitis: A bibliometric and visualized study from 2011 to 2021.

Background: Ulcerative colitis (UC) is an idiopathic inflammatory bowel disease with repeated relapses and remissions. Despite decades of effort, numerous aspects, including the initiating event and pathogenesis of UC, still remain ambiguous, which requires ongoing investigation. Given the mass of publications on UC, there are multidimensional challenges to evaluating the scientific impact of relevant work and identifying the current foci of the multifaceted disease. Accordingly, herein, we aim to assess the global growth of UC research production, analyze patterns of research areas, and evaluate trends in this area. Methods: The Web of Science Core Collection of Clarivate Analytics was searched for articles related to UC published from 2011 to 2021. Microsoft Office Excel 2019 was used to visualize the number of publications over time. Knowledge maps were generated using CiteSpace and VOSviewer to analyze collaborations among countries, institutions, and authors and to present the journey of UC research as well as to reveal the current foci of UC research. Results: A total of 5,088 publications were evaluated in the present study. China had the most publications (1,099, 22.5%). Univ Calif San Diego was the most productive institution (126, 2.48%). William J Sandborn published the greatest number of articles (100, 1.97%). Toshifumi Hibi was the most influential author in the field with a betweenness centrality of 0.53. Inflammatory bowel diseases was identified as the most prolific journal (379, 7.45%). Gastroenterology was the most co-cited journal (3,730, 4.02%). “Vedolizumab,” “tofacitinib,” “Faecalibacterium prausnitzii,” “fecal microbiota transplantation (FMT),” “toll-like receptor 4,” and “nucleotide-binding oligomerization domain-like receptor protein 3 inflammasome” were considered the hot topics. Conclusion: In UC research, manuscripts that had high impacts on the scientific community provided an evidence base. UC therapy has entered the era of personalized and precision therapy. As research on FMT, anti-integrin antibodies, Janus kinase inhibitors, and anti-tumor necrosis factor drugs continues to grow, their use in the clinical setting may also expand.

Integrin β1, PDGFRβ, and type II collagen are essential for meniscus regeneration by synovial mesenchymal stem cells in rats

Synovial mesenchymal stem cells (MSCs) injected into the knee promote meniscus regeneration in several animal models; however, the mode of action is unknown. Our purpose was to identify the molecules responsible for this meniscus regeneration. Rat synovial MSCs were treated with neutralizing antibodies for integrin β1, PDGFRβ, or CD44 or with the CRISPR/Cas9 system to delete Vcam1, Tnfr1, or Col2a1 genes. After partial meniscectomy, rat knees were injected with MSCs, and the regenerated meniscus area was quantified three weeks later. The in vivo and in vitro functions were compared between the treated and control MSCs. Anti-integrin β1 neutralizing antibody inhibited in vitro MSC adhesion to collagen-coated chambers, anti-PDGFRβ neutralizing antibody inhibited proliferation in culture dishes, and Col2a1 deletion inhibited in vitro chondrogenesis. In vivo, the regenerated meniscus area was significantly smaller after injection of MSCs treated with integrin β1 and PDGFRβ neutralizing antibodies or lacking type II collagen gene than after control MSC injection. By contrast, the regenerated areas were similar after injection of control, CD44-, Vcam1-, or Tnfr1 treated MSCs (n = 12–16) MSCs. Synovial MSCs injected into the knee joint promoted meniscus regeneration by adhesion to integrin β1 in the meniscectomized region, proliferation by PDGFRβ, and cartilage matrix production from type II collagen.

Modification of Fibronectin by Non-Enzymatic Glycation Impairs K+ Channel Function in Rat Cerebral Artery Smooth Muscle Cells.

Fibronectin (FN) enhances K+ channel activity by integrin-mediated mechanisms. As vascular smooth muscle (VSM) K+ channels mediate vasodilation, we hypothesized that modification of fibronectin, via advanced non-enzymatic glycation, would alter signaling of this extracellular matrix protein through these channels. Bovine FN (1 mg/ml) was glycated (gFN) for 5 days using methylglyoxal (50 mM), and albumin was similarly glycated as a non-matrix protein control. VSM cells were isolated from rat cerebral arteries for measurement of macroscopic K+ channel activity using whole cell patch clamp methodology. Pharmacological inhibitors, iberiotoxin (0.1 μM) and 4-aminopyridine (0.1 mM), were used to identify contributions of large-conductance, Ca2+-activated, K+ channels and voltage-gated K+ channels, respectively. Compared with baseline, native FN enhanced whole cell K+ current in a concentration-dependent manner, whereas gFN inhibited basal current. Furthermore, native albumin did not enhance basal K+ current, but the glycated form (gAlb) caused inhibition. gFN was shown to impair both the Kv and BKCa components of total macroscopic K+ current. Anti-integrin α5 and β1 antibodies attenuated the effects of both FN and gFN on macroscopic K+ current at +70 mV. Consistent with an action on BKCa activity, FN increased, whereas gFN decreased the frequency of spontaneous transient outward current (STOCs). In contrast, gAlb inhibited whole cell K+ current predominantly through Kv, showing little effect on STOCs. A function-blocking, anti-RAGE antibody partially reversed the inhibitory effects of gFN, suggesting involvement of this receptor. Further, gFN caused production of reactive oxygen species (ROS) by isolated VSMCs as revealed by the fluorescent indicator, DHE. Evoked ROS production was attenuated by the RAGE blocking antibody. Collectively, these studies identify ion channel-related mechanisms (integrin and ROS-mediated) by which protein glycation may modify VSMC function.