Recombinant Intercellular Adhesion Molecule-1 Research Articles

Integration of single-cell RNA sequencing of endothelial cells and proteomics to unravel the role of ICAM1-PTGS2 communication in apical periodontitis: A laboratory investigation.

Endothelial cells (EDs) play a key role in angiogenesis and are associated with granulomatous lesions in patients with chronic apical periodontitis (CAP). This study aimed to investigate the diversity of EDs using single-cell ribonucleic acid sequencing (scRNA-seq) and to evaluate the regulation of intercellular adhesion molecule 1 (ICAM1) on the ferroptosis-related protein, prostaglandin-endoperoxide synthase 2 (PTGS2), in CAP. EDs from the uploaded scRNA-seq data of five CAP samples (GSE181688 and GSE197680) were categorized using distinct marker genes. The interactions between vein EDs (veinEndo) and other cell types were analysed using CellPhoneDB. Differentially expressed proteins in the proteomics of human umbilical vein EDs (HUVECs) and THP-1-derived macrophages infected with Porphyromonas gingivalis were compared with the differentially expressed genes (DEGs) of VeinEndo in scRNA-seq of CAP versus healthy control periodontal tissues. The protein-protein interaction of ICAM1-PTGS2 in macrophages and HUVECs was validated by adding recombinant ICAM1, ICAM1 inhibitor and PTGS2 inhibitor using real-time polymerase chain reaction (PCR), western blotting, and immunofluorescence staining. EDs in patients with CAP were divided into eight subclusters: five vein ED, capillaries, arterials and EC (PLA). There were 29 mutually upregulated DEGs and two mutually downregulated DEGs in vein cells in the scRNA-seq data, as well as differentially expressed proteins in the proteomics of HUVECs. Real-time PCR and immunofluorescence staining showed that ICAM1 and PTGS2 were highly expressed in CAP, infected HUVECs, and macrophages. Recombinant protein ICAM1 may improve PTGS2 expression, reactive oxygen species (ROS), and Fe2+ levels and decrease glutathione peroxidase 4 (GPX4) and SLC7A11 protein levels. ICAM1 inhibitor may inverse the above changes. scRNA-seq revealed the diversity of EDs in CAP and identified the possible regulation of ICAM1 by the ferroptosis-related protein, PTGS2, in infected HUVECs and macrophages, thus providing a basis for therapeutic approaches that target the inflammatory microenvironment of CAP.

Generation of high affinity ICAM-1-specific nanobodies and evaluation of their suitability for allergy treatment.

The nasal cavity is an important site of allergen entry. Hence, it represents an organ where trans-epithelial allergen penetration and subsequent IgE-mediated allergic inflammation can potentially be inhibited. Intercellular adhesion molecule 1 (ICAM-1) is highly expressed on the surface of respiratory epithelial cells in allergic patients. It was identified as a promising target to immobilize antibody conjugates bispecific for ICAM-1 and allergens and thereby block allergen entry. We have previously characterized a nanobody specific for the major birch pollen allergen Bet v 1 and here we report the generation and characterization of ICAM-1-specific nanobodies. Nanobodies were obtained from a camel immunized with ICAM-1 and a high affinity binder was selected after phage display (Nb44). Nb44 was expressed as recombinant protein containing HA- and His-tags in Escherichia coli (E.coli) and purified via affinity chromatography. SDS-PAGE and Western blot revealed a single band at approximately 20 kDa. Nb44 bound to recombinant ICAM-1 in ELISA, and to ICAM-1 expressed on the human bronchial epithelial cell line 16HBE14o- as determined by flow cytometry. Experiments conducted at 4°C and at 37°C, to mimic physiological conditions, yielded similar percentages (97.2 ± 1.2% and 96.7 ± 1.5% out of total live cells). To confirm and visualize binding, we performed immunofluorescence microscopy. While Texas Red Dextran was rapidly internalized Nb44 remained localized on the cell surface. Additionally, we determined the strength of Nb44 and ICAM-1 interaction using surface plasmon resonance (SPR). Nb44 bound ICAM-1 with high affinity (10-10 M) and had slow off-rates (10-4 s-1). In conclusion, our results showed that the selected ICAM-1-specific nanobody bound ICAM-1 with high affinity and was not internalized. Thus, it could be further used to engineer heterodimers with allergen-specific nanobodies in order to develop topical treatments of pollen allergy.

Kinetics and interaction studies of anti-tetraspanin antibodies and ICAM-1 with extracellular vesicle subpopulations using continuous flow quartz crystal microbalance biosensor

Continuous flow quartz crystal microbalance (QCM) was utilized to study binding kinetics between EV subpopulations (exomere- and exosome-sized EVs) and four affinity ligands: monoclonal antibodies against tetraspanins (anti-CD9, anti-CD63, and anti-CD81) and recombinant intercellular adhesion molecule-1 (ICAM-1) or CD54 protein). High purity CD9+, CD63+, and CD81+ EV subpopulations of <50 nm exomeres and 50–80 nm exosomes were isolated and fractionated using our recently developed on-line coupled immunoaffinity chromatography – asymmetric flow field-flow fractionation system. Adaptive Interaction Distribution Algorithm (AIDA), specifically designed for the analysis of complex biological interactions, was used with a four-step procedure for reliable estimation of the degree of heterogeneity in rate constant distributions. Interactions between exomere-sized EVs and anti-tetraspanin antibodies demonstrated two interaction sites with comparable binding kinetics and estimated dissociation constants Kd ranging from nM to fM. Exomeres exhibited slightly higher affinity compared to exosomes. The highest affinity with anti-tetraspanin antibodies was achieved with CD63+ EVs. The interaction of EV subpopulations with ICAM-1 involved in cell internalization of EVs was also investigated. EV – ICAM-1 interaction was also of high affinity (nM to pM range) with overall lower affinity compared to the interactions of anti-tetraspanin antibodies and EVs. Our findings proved that QCM is a valuable label-free tool for kinetic studies with limited sample concentration, and that advanced algorithms, such as AIDA, are crucial for proper determination of kinetic heterogeneity. To the best of our knowledge, this is the first kinetic study on the interaction between plasma-derived EV subpopulations and anti-tetraspanin antibodies and ICAM-1.

Biotinylation Assay to Determine LFA-1 Recycling in Motile T-Lymphocytes.

The cycles of internalization of the cell surface β2 integrin receptor lymphocyte function-associated antigen 1 (LFA-1) and its re-exposure on the plasma membrane are important for T-cell trafficking. Biotinylation of cells enables to measure surface expression of receptors, and after reducing surface biotin with reducing buffer, enables to measure the internalization of receptors. Here, by using biotin in combination with reducing buffer and recombinant intercellular adhesion molecule-1 (rICAM-1)-coated dishes and subsequent Western immunoblot analysis, we describe how to measure internalization of the LFA-1 receptor and its re-expression back to the cell surface in motile T-lymphocytes.

Antibody conjugates bispecific for intercellular adhesion molecule 1 and allergen prevent migration of allergens through respiratory epithelial cell layers

Antibody conjugates bispecific for intercellular adhesion molecule 1 and allergen prevent migration of allergens through respiratory epithelial cell layers

FRET based quantification and screening technology platform for the interactions of leukocyte function-associated antigen-1 (LFA-1) with intercellular adhesion molecule-1 (ICAM-1).

The interaction between leukocyte function-associated antigen-1(LFA-1) and intercellular adhesion molecule-1 (ICAM-1) plays a pivotal role in cellular adhesion including the extravasation and inflammatory response of leukocytes, and also in the formation of immunological synapse. However, irregular expressions of LFA-1 or ICAM-1 or both may lead to autoimmune diseases, metastasis cancer, etc. Thus, the LFA-1/ICAM-1 interaction may serve as a potential therapeutic target for the treatment of these diseases. Here, we developed one simple ‘in solution’ steady state fluorescence resonance energy transfer (FRET) technique to obtain the dissociation constant (Kd) of the interaction between LFA-1 and ICAM-1. Moreover, we developed the assay into a screening platform to identify peptides and small molecules that inhibit the LFA-1/ICAM-1 interaction. For the FRET pair, we used Alexa Fluor 488-LFA-1 conjugate as donor and Alexa Fluor 555-human recombinant ICAM-1 (D1-D2-Fc) as acceptor. From our quantitative FRET analysis, the Kd between LFA-1 and D1-D2-Fc was determined to be 17.93±1.34 nM. Both the Kd determination and screening assay were performed in a 96-well plate platform, providing the opportunity to develop it into a high-throughput assay. This is the first reported work which applies FRET based technique to determine Kd as well as classifying inhibitors of the LFA-1/ICAM-1 interaction.

Transfected HEK293 Cells Expressing Functional Recombinant Intercellular Adhesion Molecule 1 (ICAM-1) – A Receptor Associated with Severe Plasmodium falciparum Malaria

Intercellular adhesion molecule 1 (ICAM-1) is a membrane-bound glycoprotein expressed on endothelial cells and cells of the immune system. Human ICAM-1 mediates adhesion and migration of leucocytes, and is implicated in inflammatory pathologies, autoimmune diseases and in many cancer processes. Additionally, ICAM-1 acts as receptor for pathogens like human rhinovirus and Plasmodium falciparum malaria parasites. A group of related P. falciparum erythrocyte membrane protein 1 (PfEMP1) domains, the DBLβ, mediates ICAM-1 binding of P. falciparum-infected erythrocytes. This ICAM‑1-binding phenotype has been suggested to be involved in the development of cerebral malaria. However, more studies identifying cross-reactive antibody and ICAM-1-binding epitopes and the establishment of a clinical link between DBLβ expression and e.g. cerebral malaria are needed before the DBLβ domains can be put forward as vaccine candidates and go into clinical trials. Such studies require availability of functional recombinant ICAM-1 in large quantities. In this study, we compared recombinant ICAM-1 expressed in HEK293 and COS-7 cells with mouse myeloma NS0 ICAM-1 purchased from a commercial vendor in terms of protein purity, yield, fold, ability to bind DBLβ, and relative cost. We present a HEK293 cell-based, high-yield expression and purification scheme for producing inexpensive, functional ICAM‑1. ICAM-1 expressed in HEK293 is applicable to malaria research and can also be useful in other research fields.

Recombinant production of human ICAM-1 chimeras by single step on column refolding and purification

The interaction of the adhesion molecule of the immunoglobulin family intercellular adhesion molecule 1 (ICAM-1) with its ligands such that the integrins LFA-1 and Mac-1 is crucial for the regulation of several physiological and pathophysiological processes like cell mediated-elimination of tumor or virus infected cells, cancer metastasis or inflammatory autoimmune processes. Thus, production of milligrams of protein is required to perform structural and functional studies as well as design novel approaches to find out new inhibitors of ICAM-1/LFA-1 interaction. Here we report on the production of a recombinant human ICAM-1 chimera comprising the first two extracellular domains of ICAM-1 linked to the Fc fraction of a human IgG1. To this aim we have used a cost-effective method based on the expression of a His-tagged protein in Escherichia coli followed by a single step of refolding and purification on immobilized metal affinity columns. This method is able to produce 3mg/l of bacterial culture in just 72h with purity greater than 95%. The identity and the native structure of refolded human ICAM-1 chimera were confirmed by biochemical and biophysical studies including SDS-electrophoresis, immunoblot, circular dichroism, isothermal titration calorimetry and fluorescence spectroscopy. Native folding and functional activity of the chimera were further confirmed by different cell biology studies, including B cell adhesion, T cell binding and inhibition of NK cell function. These studies indicate a high biological activity of the protein since it induces a 200-fold increase/mg of protein in B cell adhesion and the inhibitory dose 50 to block cell-mediated cytotoxicity is 10pg/effector cell. These analyses show that our protocol is able to produce a recombinant human ICAM-1 chimera fully active and useful to analyze the biological processes in which ICAM-1/LFA-1 interaction is critically involved.

MUC1 is involved in trophoblast transendothelial migration

The factors that regulate trophoblast invasion of the uterine vasculature are incompletely understood. In this paper we show that macaque trophoblasts express the mucin, MUC1, and that it is involved in trophoblast-endothelial interaction. Immunocytochemistry, Western blotting and RT-PCR analyses confirmed that MUC1 was expressed by isolated early gestation macaque trophoblasts. MUC1 was also detected in endovascular trophoblasts in sections of placental–decidual tissue during early gestation. A blocking antibody against MUC1 reduced trophoblast adhesion to uterine endothelial cells and also blocked trophoblast transendothelial migration. MUC1 is known to bind to Intercellular Adhesion Molecule-1 (ICAM-1) in other systems. Incubation in the presence of a blocking antibody against Intercellular Adhesion Molecule-1 (ICAM-1) or recombinant ICAM-1 modestly, but significantly, reduced transendothelial trophoblast migration. These results are consistent with the idea that MUC1 is involved in trophoblast adhesion to uterine endothelial cells and in trophoblast transendothelial migration.

Engagement of PSGL-1 enhances beta2-integrin-involved adhesion of neutrophils to recombinant ICAM-11

The interactions of selectins and their ligands initiate the process of leukocyte migrating into inflamed tissue. P-selectin glycoprotein ligand 1 (PSGL-1) is the best characterized ligand of selectins, and has been demonstrated to mediate the adhesion of leukocytes to all three selectins in vivo. PSGL-1 not only functions as an anchor molecule to capture the leukocytes to the activated endothelial cells by its interaction with selectins, but also transduces the signals to activate leukocytes. Our present work aimed to investigate the mechanism by which PSGL-1-mediated signal activates neutrophils and enhances the adhesion to the endothelial cells. We detected the effects of the engagement of PSGL-1 with monoclonal antibodies (mAb) or P-selectin on the adhesion of neutrophils to the recombinant intercellular adhesion molecule-1 (ICAM-1), and on the expression of beta(2)-integrin. Additionally, the role of cytoskeleton in these process was studied by using inhibitor cytochalasin B. The engagement of PSGL-1 increased the expression of beta(2)-integrin on the surface of neutrophils and enhanced the adhesion of neutrophils to the recombinant ICAM-1. mAb against CD18 impaired the adhesion of PSGL-1-engaged neutrophils to ICAM-1. Moreover, the inhibitor cytochalasin B largely blocked the increase of CD18 expression as well as the adhesion of PSGL-1-engaged neutrophils to ICAM-1. The PSGL-1-transduced signals can enhance beta(2)-integrin-involved adhesion of neutrophils to the recombinant ICAM-1, and this process depends on the dynamics of cytoskeleton.

IFN-beta decreases adhesion and transmigration capacities of lymphocytes in Guillain-Barré syndrome.

The adhesion capacities, transmigration capacities, and integrin expression of lymphocytes from patients with Guillain-Barré syndrome incubated with interferon-beta were studied. Interferon-beta induced a dose-dependent inhibition of lymphocyte adhesion to recombinant vascular adhesion molecule-1 (p < 0.0001) and recombinant intercellular adhesion molecule-1 (rICAM-1) (p < 0.01) without modulation of very late activation molecule-4 and lymphocyte function-associated antigen-1 expressions and a dose-dependent decrease of lymphocyte transmigration across fibronectin (p < 0.0001). Inhibition of adhesion to rICAM-1 was similar after long (18 hours) or short (5 minutes) incubation time. These results support the potential therapeutic benefit of interferon-beta in Guillain-Barré syndrome.

Effect of mechanical deformation of neutrophils on their CD18/ICAM-1-dependent adhesion.

Mechanical deformation of polymorphonuclear leukocytes (PMN) changes their expression of the surface adhesion molecule CD11b/CD18. We tested the hypothesis that mechanical deformation of PMN enhances their adhesiveness. Purified human PMN were deformed through either 5- or 3-microm polycarbonate membrane filters and allowed to adhere to 96-well plates coated with human recombinant intercellular adhesion molecule-1 (ICAM-1). Flow cytometric studies showed that deformation of PMN increased CD11b/CD18 expression (P < 0.01). PMN adhesion to ICAM-1-coated plates was dependent on the magnitude of cell deformation (5 microm, 63.8 +/- 8.1%, P < 0.04; 3 microm, 232.4 +/- 20.9%, P < 0.01). Priming of PMN (0.5 nM N-formyl-methionyl-leucyl-phenylalanine) before deformation (5 microm) increased PMN adhesion (63.8 +/- 8.1 vs. 105.3 +/- 16.4%; P < 0.04). Stimulation (5% zymosan-activated plasma) of PMN after deformation resulted in increased adhesion, and the degree of increase was dependent on the magnitude of PMN deformation (stimulation, 50.6 +/- 4%; 5-microm filtration and stimulation, 62.9 +/- 6.6%; 3-microm filtration and stimulation, 249.9 +/- 24.2%; P < 0.01). This study shows that mechanical deformation of PMN causes an increase in PMN adhesiveness to ICAM-1 that was enhanced by both priming of PMN before deformation and stimulation after cell deformation.

Soluble ICAM-1 reduces leukocyte adhesion to vascular endothelium in ischemia-reperfusion injury in mice.

Ischemia-reperfusion injury is a pathogenic factor in the course of many clinical disorders, such as myocardial infarction, stroke, organ transplantation, burns, and circulatory shock. The extent of ischemia-reperfusion injury is dependent on the number of infiltrating leukocytes. With in vivo microscopy, we evaluated the effect of the recombinant form of soluble murine intercellular adhesion molecule-1 (ICAM-1) on ischemia-reperfusion injury in an animal model. A mesenteric vein was occluded with a clamp for 45 min. During a reperfusion period of 30 min, the number of leukocytes rolling along the endothelium and the number of adherent leukocytes were measured with and without pretreatment with recombinant ICAM-1. The number of leukocytes rolling along the endothelial surface increased more than twofold during postischemic perfusion (P < 0.05). Recombinant ICAM-1 had no effect on leukocyte rolling. In the control group, firm adherence of leukocytes was increased 10-fold. Recombinant ICAM-1 dose dependently reduced firm adhesion to the endothelium in response to prior ischemia. After 30 min, reperfusion pretreatment with recombinant ICAM-1 inhibited leukocyte adherence from 512 +/- 123 to 166 +/- 34 leukocytes/mm2 (P < 0.01). We demonstrate here for the first time that soluble recombinant ICAM-1 is able to reduce leukocyte adherence to mesenteric venules in postischemic reperfusion injury dose dependently. Because soluble ICAM-1 is naturally circulating in human serum, the therapeutic use of soluble recombinant forms of ICAM-1 may represent a physiological way to protect against ischemiareperfusion injury.

A role for the alphavbeta3 integrin in the transmigration of monocytes.

The beta2 integrins and intercellular adhesion molecule-1 (ICAM-1) are important for monocyte migration through inflammatory endothelium. Here we demonstrate that the integrin alphavbeta3 is also a key player in this process. In an in vitro transendothelial migration assay, monocytes lacking beta3 integrins revealed weak migratory ability, whereas monocytes expressing beta3 integrins engaged in stronger migration. This migration could be partially blocked by antibodies against the integrin chains alphaL, beta2, alphav, or IAP, a protein functionally associated with alphavbeta3 integrin. Transfection of beta3 integrin chain cDNA into monocytes lacking beta3 integrins resulted in expression of the alphavbeta3 integrin and conferred on these cells an enhanced ability to transmigrate through cell monolayers expressing ICAM-1. These monocytes also engaged in alphaLbeta2-dependent locomotion on recombinant ICAM-1 which was enhanced by alphavbeta3 integrin occupancy. Antibodies against IAP were able to revert this alphavbeta3 integrin-dependent cell locomotion to control levels. Finally, adhesion assays revealed that occupancy of alphavbeta3 integrin could decrease monocyte binding to ICAM-1. In conclusion, we show that alphavbeta3 integrin modulates alphaLbeta2 integrin-dependent monocyte adhesion to and migration on ICAM-1. This could represent a novel mechanism to promote monocyte motility on vascular ICAM-1 and initiate subsequent transendothelial migration.

A rapid activation assay for human eosinophils based on adhesion to immobilized ICAM-1, VCAM-1 and IgG.

Interleukin 5 (IL-5) is a T-cell derived cytokine that induces eosinophil growth and differentiation in both mouse and human bone marrow cultures. Elevated levels of IL-5 as well as eosinophils have been detected in the sputum and Bronchoalveolar lavage (BAL) fluids of asthmatics. Since the recruitment of inflammatory cells to tissues requires the participation of adhesion molecules, we have developed a rapid and sensitive assay to examine the effect of IL-5 and other activation stimuli on eosinophil adhesion to recombinant intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1). Human recombinant IL-5, granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin 3 (IL-3), tumour necrosis factor alpha (TNF-alpha), RANTES, MCP-3, C5a, PAF, fMLP, PMA and ConA all induced adhesion of purified eosinophils obtained from normal donors to ICAM-1 and VCAM-1 in a dose and time dependent manner. Adhesion was rapid, within 15 minutes of culture at 37 degrees C, and plateaued within 30 minutes. Activated eosinophils also adhered rapidly to immobilized IgG via the type II Fc gamma receptor (CD32). Analysis of the effect of IL-5 on surface molecule expression by FACS analysis revealed increased expression of CD11b molecules and decreased expression of L-selectin, but no change in the expression of CD11a, CD18, CD29, CD49d and CD32. We also show that Mac-i plays an important role in the regulation of eosinophil activation, since antibodies to CD11b can block IL-5 induced adhesion to IgG and IL-5 induced degranulation.

A truncated recombinant intercellular adhesion molecule-1 inhibits adhesion of leukemic cell lines to upregulated endothelial cells

Intercellular adhesion molecule-1, a member of the immunoglobulin supergene family, is the ligand for the integrin lymphocyte function associated antigen-1. Intercellular adhesion molecule-1 and lymphocyte function associated antigen-1 binding interactions mediate leukocyte adherence and migration. Previous work has shown that the adherence of lymphocyte function associated antigen-1 is directed to the first immunoglobulinlike domain of the endothelial cell surface protein intracellular adhesion molecule-1. We have constructed a truncated intercellular adhesion molecule-1 gene encoding the first 185 amino acids from the amino terminus and overexpressed it in Escherichia coli. The recombinant protein was purified from insoluble inclusion bodies and refolded into an active conformation by a denaturation/renaturation cycle. The identity of the protein was confirmed by microsequencing and by Western blot analysis using a polyclonal antibody to ICAM-1. We have demonstrated that this soluble region of the otherwise membrane-bound ligand is an inhibitor of Molt or HL-60 cell adhesion to cytokine-stimulated endothelial cells.

I domain of beta 2 integrin lymphocyte function-associated antigen-1 contains a binding site for ligand intercellular adhesion molecule-1.

Lymphocyte function-associated antigen-1 (LFA-1) is a beta 2 integrin that participates in a broad range of leukocyte functions through binding to its ligand intercellular adhesion molecule-1 (ICAM-1). The location of the ICAM-1 binding site on LFA-1 is not known. A approximately 200-amino acid "inserted" or "I" domain, which is part of the beta 2 integrin alpha subunit, is homologous to the "A" domains found in the adhesive protein von Willebrand factor and in a number of other proteins. In von Willebrand factor, the A domains are involved in ligand binding, but their function in the other proteins is still unclear. In this report, we show that the LFA-1 I domain contains a binding site for ICAM-1, which can be expressed as an isolated functional unit. The I domain contains the epitopes for 18 out of 20 anti-LFA-1 monoclonal antibodies, many of which interfere with the interaction between LFA-1 and ICAM-1. The I domain binds directly to purified recombinant ICAM-1 and also inhibits LFA-1-dependent T cell adhesion to ICAM-1. This report establishes the I domain as an ICAM-1 binding region in LFA-1 and the first ligand binding site to be identified in a beta 2 integrin.