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Placentation is a major determinant of the success of pregnancy. It is regulated by several factors such as cell adhesion molecules, tight junctions, and gap junctions. The cell adhesion molecules are integrins, cadherins, immunoglobulins, nectins, and selectins. The tight junctions are composed of claudins, occludin, and junction adhesion molecule proteins while the gap junctions are composed of connexins of varying molecular weights. During placentation, some of these molecules regulate trophoblast proliferation, trophoblast fusion, trophoblast migration, trophoblast invasion, trophoblast-endothelium adhesion, glandular remodeling, and spiral artery remodeling. There is a dysregulated placental expression of some of these molecules during obstetric complications. We have, hereby, indicated the expression patterns of the subunits of each of these molecules in the various trophoblast subtypes and in the decidua, and have highlighted their involvement in physiological and pathological placentation. The available evidence points to the relevance of these molecules as distinguishing markers of the various trophoblast lineages and as potential therapeutic targets in the management of malplacentation-mediated diseases. [ABSTRACT FROM AUTHOR]

L-selectin is a cell adhesion molecule that plays an important role in modulating immune cell trafficking. The expression of L-selectin has been found to be upregulated in several human cancers. However, the association of L-selectin expression with the immune profile and its prognostic value in breast cancer has not been explored in detail. We utilized TCGA and Oncomine datasets to compare SELL (L-selectin gene) expression between tumor and normal breast tissues. The association of SELL expression with its promoter DNA methylation and infiltrating immune cells was evaluated by using Wanderer, TIMER, and CIBERSORT tools. Single cell RNA sequencing data was utilised to determine the cell specific expression of L-selectin in breast cancer. Furthermore, the relationship between SELL expression and patient survival was evaluated using the Kaplan–Meier plotter. Gene set enrichment analysis was performed to determine functional associations of SELL expression. We found that SELL expression was significantly higher in breast tumors and regulated by DNA methylation. L-selectin exhibited a strong positive correlation with markers of the inflammatory microenvironment, including M1 macrophages. Interestingly, single cell sequencing data analysis revealed that B-cells and T-cells exhibited comparable expression levels of SELL, suggesting both B-cells and T cells contribute to SELL expression in breast cancer. Higher expression of SELL was associated with better survival outcome in basal, Her2 + and luminal B subtypes of breast cancer. GSEA revealed association of SELL expression with several immunological features in breast cancer. SELL expression increases in breast tumor tissues with reduced DNA methylation and associated inflammatory microenvironment. Also, high SELL expression is associated with favorable survival outcomes in breast cancer. [ABSTRACT FROM AUTHOR]

Introduction: The glycocalyx is a layer of glycoproteins, proteoglycans and glycosaminoglycans that coats the luminal surface of most blood vessels. It effectively regulates adhesive interactions between leukocytes in flowing blood and the endothelium, where during inflammation, binding to E- and P-selectins and intercellular adhesion molecule-1 (ICAM-1) promotes cell tethering and arrest under shear flow.Methods: In this study, we examine the targeting of E-selectin by an engineered peptide moiety bound to a dermatan sulfate backbone. We further investigate this conjugate, denoted as EC-SEAL, by observing its binding to inflamed endothelium, and quantifying its ability to modulate neutrophil-endothelium interactions.Results: Binding data reveal that EC-SEAL recognizes domains on E-selectin, and to a lesser degree on P- and L-selectin, and ICAM-1. Further, EC-SEAL increases neutrophil rolling velocity, and decreases neutrophil arrest and migration on inflamed human microvascular endothelial cells under physiologically relevant flow conditions.Conclusions: We conclude that simple targeting strategies can mimic glycocalyx function under inflammatory conditions, effectively reducing neutrophil recruitment. [ABSTRACT FROM AUTHOR]

Purpose: The purposes of the present study is to evaluate a new ultrasound molecular imaging approach in its ability to image a preclinical tumor model and to investigate the capacity to visualize and quantify co-registered microvascular and molecular imaging volumes.Procedures: Molecular imaging using the new technique was compared with a conventional ultrasound molecular imaging technique (multi-pulse imaging) by varying the injected microbubble dose and scanning each animal using both techniques. Each of the 14 animals was randomly assigned one of three doses; bolus dose was varied, and the animals were imaged for three consecutive days so that each animal received every dose. A microvascular scan was also acquired for each animal by administering an infusion of nontargeted microbubbles. These scans were paired with co-registered molecular images (VEGFR2-targeted microbubbles), the vessels were segmented, and the spatial relationships between vessels and VEGFR2 targeting locations were analyzed. In five animals, an additional scan was performed in which the animal received a bolus of microbubbles targeted to E- and P-selectins. Vessel tortuosity as a function of distance from VEGF and selectin targeting was analyzed in these animals.Results: Although resulting differences in image intensity due to varying microbubble dose were not significant between the two lowest doses, superharmonic imaging had significantly higher contrast-to-tissue ratio (CTR) than multi-pulse imaging (mean across all doses 13.98 dB for molecular acoustic angiography vs. 0.53 dB for multi-pulse imaging; p = 4.9 × 10-10). Analysis of registered microvascular and molecular imaging volumes indicated that vessel tortuosity decreases with increasing distance from both VEGFR2- and selectin-targeting sites.Conclusions: Molecular acoustic angiography (superharmonic molecular imaging) exhibited a significant increase in CTR at all doses tested due to superior rejection of tissue artifact signals. Due to the high resolution of acoustic angiography molecular imaging, it is possible to analyze spatial relationships in aligned microvascular and molecular superharmonic imaging volumes. Future studies are required to separate the effects of biomarker expression and blood flow kinetics in comparing local tortuosity differences between different endothelial markers such as VEGFR2, E-selectin, and P-selectin. [ABSTRACT FROM AUTHOR]

Several cell adhesion molecules (CAMs) including selectins, integrins, cadherins and immunoglobulin-like CAMs are involved in leukocyte adhesion especially at sites of inflammation. In cancer cells, these CAMs have been associated with the growth and metastatic behavior in several malignant entities. In this study adhesion of LAN 1 and SK-N-SH neuroblastoma cells to selectins, hyaluronan and endothelial cells were determined under flow conditions. Furthermore cells were injected subcutaneously into wildtype and selectin deficient scid mice and their growth and metastatic behavior were analyzed. Under shear stress SK-N-SH cells firmly adhered to E-selectin-Fc-fusion protein, hyaluronan and endothelial cells, while LAN 1 cells showed less or hardly any adhesive events by comparison. In the SK-N-SH xenograft model metastasis formation was slightly dependent on the expression of selectins, while LAN 1 cells developed metastases completely independent of selectin expression. The different adhesive and metastatic properties of LAN 1 and SK-N-SH cells are reflected by a different expression profile of several CAMs. The results indicate that endothelial selectins are not essential for metastasis formation of human LAN 1 and SK-N-SH cells. However, other CAMs namely CD44, N-cadherin, NCAM and integrins were upregulated or downregulated, respectively, in SK-N-SH and LAN 1 cells and are potential adhesion molecules involved in the metastatic cascade of these cells. [ABSTRACT FROM AUTHOR]

Distant metastasis account for about 90 % of cancer associated deaths, and yet the oncology field is cruelly lacking tools to accurately predict and/or prevent metastasis. Distant metastasis occurs when circulating tumor cells interact with the endothelium of distant organs and extravasate from the blood vessel into the surrounding tissue. Selectins are a family of carbohydrate receptors well depicted for their role in tumor cells extravasation. They mediate primary interactions of cancer cells with endothelial cells, as well as secondary interactions with leucocytes and platelets, which are also promoting metastasis. The cancer associated carbohydrate antigen sialyl-Lewis x (sLe x) has been repeatedly shown to be involved, as selectin ligand, in these interactions. However, recent studies have highlighted that glycosaminoglycans (GAGs), another class of glycans, may also serve as ligands for selectins. We report herein that cancer-associated GAGs are differentially recognized by selectins according to their density of sulfation and the pH conditions of the binding. We also show that these parameters regulate platelets-cancer cells heterotypic aggregation, supporting the idea that GAGs may have pro-metastatic function. Combining our experimental results with in depth analyses of molecular dockings, we propose a model of GAG/selectin interactions robust enough to recapitulate the differential binding of selectins to GAGs, the competition between GAGs and sLe x for selectin binding and the effect of sub-physiological pH on GAGs affinities towards selectins. Altogether, our data suggest GAGs to be good ligands for selectins, potentially promoting distant metastasis in a complementary way to sLe x. [ABSTRACT FROM AUTHOR]

Purpose: To improve the delivery of liposomes to tumors using P-selectin glycoprotein ligand 1 (PSGL1) mediated binding to selectin molecules, which are upregulated on tumorassociated endothelium. Methods: PSGL1 was orientated and presented on the surface of liposomes to achieve optimal selectin binding using a novel streptavidin-protein G linker molecule. Loading of PSGL1 liposomes with luciferin allowed their binding to e-selectin and activated HUVEC to be quantified in vitro and their stability, pharmacokinetics and tumor accumulation to be tested in vivo using murine models. Results: PSGL1 liposomes showed 5-fold ( p < 0.05) greater selectin binding than identically formulated control liposomes modified with ligand that did not contain the selectin binding domain. When added to HUVEC, PSGL1 liposomes showed >7-fold ( p < 0.001) greater attachment than control liposomes. In in vivo studies PSGL1 liposomes showed similar stability and circulation to control liposomes but demonstrated a >3-fold enhancement in the level of delivery to tumors ( p < 0.05). Conclusions: The technologies and strategies described here may contribute to clinical improvements in the selectivity and efficacy of liposomal drug delivery agents. [ABSTRACT FROM AUTHOR]

Leukocyte recruitment into tissue forms the basis of immune surveillance and direct immune defense. It proceeds in a cascade-like fashion. The first contact of leukocytes with the endothelium is mediated by selectins and their counter receptors, followed by rolling and integrin-mediated arrest. While rolling, neutrophils collect different inflammatory signals which can activate several signaling pathways leading to leukocyte adhesion to the endothelium and transmigration through the blood vessel wall into the inflamed tissue. Whereas inflammatory reactions are beneficial and necessary for host defense, they need to be balanced and controlled to prevent harmful consequences and tissue destruction. In this article, we discuss the different signaling pathways that ensure rapid and efficient integrin activation on leukocytes. In addition, we report on a recently identified novel endogenous mechanism that counteracts and balances integrin activation, thereby limiting leukocyte recruitment and the extent of inflammation. Further investigation of this new mechanism may allow providing new approaches for the development of the next generation of anti-inflammatory drugs. [ABSTRACT FROM AUTHOR]

The successful clinical implementation of adoptive cell therapeutics, including bone marrow transplantation and other stem cell-based treatments, depends critically on the ability to deliver cells to sites where they are needed. E-selectin, an endothelial C-type lectin, binds sialofucosylated carbohydrate determinants on its pertinent ligands. This molecule is expressed in a constitutive manner on bone marrow and dermal microvascular endothelium, and inducibly on post-capillary venules at all sites of tissue injury. Engagement of E-selectin with relevant ligand(s) expressed on circulating cells mediates initial 'tethering/rolling' endothelial adhesive interactions prerequisite for extravasation of blood-borne cells at any target tissue. Most mammalian cells express high levels of a transmembrane glycoprotein known as CD44. A specialized glycoform of CD44 called 'Hematopoietic Cell E-/L-selectin Ligand' (HCELL) is a potent E-selectin ligand expressed on human cells. Under native conditions, HCELL expression is restricted to human hematopoietic stem/progenitor cells. We have developed a technology called 'Glycosyltransferase-Programmed Stereosubstitution' (GPS) for custom-modifying CD44 glycans to create HCELL on the surface of living cells. GPS-based glycoengineering of HCELL endows cell migration to endothelial beds expressing E-selectin. Enforced HCELL expression targets human mesenchymal stem cell homing to marrow, licensing transendothelial migration without chemokine signaling via a VLA-4/VCAM-1-dependent 'Step 2-bypass pathway.' This review presents an historical framework of the homing receptor concept, and will describe the discovery of HCELL, its function as the bone marrow homing receptor, and how enforced expression of this molecule via chemical engineering of CD44 glycans could enable stem cell-based regenerative medicine and other adoptive cell therapeutics. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs) are crucial components of the immune response, strategically positioned as immune sentinels. Complex trafficking and accurate positioning of DCs are indispensable for both immunity and tolerance. This is particularly evident for their therapeutic application where an unmet clinical need exists for DCs with improved migratory capacity upon adoptive transfer into patients. One critical step that directs the trafficking of DCs throughout the body is their egress from the vasculature, starting with their adhesive interactions with vascular endothelium under shear flow. Both tethering and rolling rely on interactions mediated by specific glycans attached to glycoproteins and glycolipids present on the DC surface. In DCs, surface glycosylation, including the expression of selectin ligands, changes significantly depending on the local microenvironment and the functional state of the cells. These changes have been documented and have potential implications in important cell functions such as migration. In this article, we review the glycobiological aspects in the context of DC interaction with endothelium, and offer insights on how it can be applied to modulate DC applicability in therapy. [ABSTRACT FROM AUTHOR]

Three hyperbranched dendrimers (polyglycidols) and the corresponding sulfated derivatives, differing in the average molecular weight, were synthesized. The compounds obtained were characterized in detail by mass spectrometry and H and C NMR spectroscopy, enabling estimation of the sizes of the corresponding molecules. Assignment of signals and identification of key structural blocks were performed using 2D homo- and heteronuclear spectroscopy (COSY, HSQC). The spectra of the sulfated derivatives showed the absence of the signals for the glycerol moiety with the free OH groups, that confirms exhaustive sulfation. The studies of antiinflammatory and anticoagulant activities of the polyanionic samples showed that all the compounds manifest weak antiinflammatory activity, however, their anticoagulant activity displayed in preliminary trials seems to be considerable. The results obtained indicate that it is reasonable to study in more detail biological activity of sulfated dendrimers of this type in terms of their anticoagulant properties. [ABSTRACT FROM AUTHOR]

The outlook for metastatic melanoma to the brain is dismal. New therapeutic avenues are therefore needed. The anti-metastatic mechanisms that may underpin the effects of low molecular weight heparins (LMWHs) in in vitro and preclinical melanoma models warrant translating to a clinical setting. This review outlines a rationale that supports our proposal that metastatic melanoma to the brain is a clinical setting in which to study the anti-metastatic potential of LMWHs. Prevention or delay of brain metastases in melanoma is a clinically relevant and measurable target. Studies to explore the effect of anticoagulants on cancer survival are underway in other malignancies such as lung, pancreas, ovary, breast, and stomach cancer. However, no study to our knowledge has a methodology that could produce clinical evidence in support of a mechanism for whatever benefit may be seen. The setting we propose would allow translation of the molecular knowledge of the metastatic pathways mediated by platelets and the selectins—all potential targets of heparin—in a “time to appearance” of brain metastases endpoint. Since brain metastases are so common and they have a singularly adverse impact on survival, the “biological neuroprotection” model we propose in metastatic melanoma could provide the translational evidence to support the benefit of LMWHs in melanoma. More significantly, this would open the door to a wider “antimetastatic” approach that could have much greater impact in patients with minimal disease being treated in adjuvant settings for the more common malignancies such as breast and colon cancer. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) kinetics of receptor–ligand interactions governs cell adhesion in many biological processes. While the dissociation kinetics of receptor–ligand bond is extensively investigated, the association kinetics has much less been quantified. Recently receptor–ligand interactions between two surfaces were investigated using a thermal fluctuation assay upon biomembrane force probe technique (Chen et al. in Biophys J 94:694–701, ). The regulating factors on association kinetics, however, are not well characterized. Here we developed an alternative thermal fluctuation assay using optical trap technique, which enables to visualize consecutive binding–unbinding transition and to quantify the impact of microbead diffusion on receptor–ligand binding. Three selectin constructs (sLs, sPs, and PLE) and their ligand P-selectin glycoprotein ligand 1 were used to conduct the measurements. It was indicated that bond formation was reduced by enhancing the diffusivity of selectin-coupled carrier, suggesting that carrier diffusion is crucial to determine receptor–ligand binding. It was also found that 2D forward rate predicted upon first-order kinetics was in the order of sPs > sLs > PLE and bond formation was history-dependent. These results further the understandings in regulating association kinetics of surface-bound receptor–ligand interactions. [ABSTRACT FROM AUTHOR]

Cancer progression is facilitated by blood coagulation. Anticoagulants, such as Hirudin and low molecular weight heparins (LMWHs), reduce metastasis mainly by inhibition of thrombin formation and L- and P-selectin-mediated cell-cell adhesion. It is unknown whether the effects are dependent on cancer cell type. The effects of anticoagulants on tumor development of K1735 and B16 melanoma cells and CT26 colon cancer cells were investigated in mouse lung. Tumor load was determined noninvasively each week up to day 21 in all experiments using bioluminescence imaging. Effects of anticoagulants on tumor development of the three cell lines were correlated with the fibrin/fibrinogen content in the tumors, expression of tissue factor (TF), protease activated receptor (PAR)-1 and -4 and CD24, a ligand of L- and P-selectins. Hirudin inhibited tumor development of B16 cells in lungs completely but did not affect tumor growth of K1735 and CT26 cells. Low molecular weight heparin did not have an effect on K1735 melanoma tumor growth either. TF and PAR-4 expression was similar in the three cell lines. PAR-1 and CD24 were hardly expressed by K1735, whereas CT26 cells expressed low levels and B16 high levels of PAR-1 and CD24. Fibrin content of the tumors was not affected by LMWH. It is concluded that effects of anticoagulants are dependent on cancer cell type and are correlated with their CD24 and PAR-1 expression. [ABSTRACT FROM AUTHOR]

The aim of this study was to reveal the distribution of various inflammation and endothelium-related adhesion molecules, namely, P-selectin, E-selectin, ICAM-1, ICAM-2, ICAM-3 and VCAM-1, on the skin samples of patients with Henoch–Schonlein purpura. Skin biopsies obtained from 12 pediatric patients at the acute purpura phase and from 5 patients at the convalescent phase of the disease were included in the study. Endothelial expression of P-selectin ( P < 0.05), endothelial and inflammatory cellular expressions of ICAM-2 ( P < 0.05, P < 0.01) and inflammatory cellular expression of ICAM-3 ( P < 0.05) were significantly more intense when compared to patients in the convalescent phase. Although endothelial E-selectin and VCAM-1 expressions, and endothelial and inflammatory cellular ICAM-1 expressions displayed a decrease in the convalesant phase, this difference was not found to be statistically significant ( P > 0.05). [ABSTRACT FROM AUTHOR]

To clarify the structure of non-sialic acid anionic residue on N-glycans in the mammalian tissues, we have isolated sialidase-resistant anionic residue on N-glycans from bovine lung. Analyses by partial acid hydrolysis and glycosidase digestions combined with a two-dimensional HPLC mapping method revealed that the major sialidase-resistant anionic N-glycan had a fucosylbianntenary core structure. The anionic residue was identified as a sulfate ester by methanolysis, anion-exchange chromatography, and mass spectrometry. The linkage position of the sulfate ester was the 6-position of the GlcNAc residue on the Manα1-6 branch. This conclusion was based on the results of glycosidase digestions followed by two-dimensional HPLC mapping. Furthermore, the disialylated form of this sulfated glycan was dominant, and no asialo form was detected. The structure of the major anionic N-glycan prepared from bovine lung and having a sulfate was proposed to be the pyridylamino derivative of Siaα2-3Gαlβ1-4(HSO3-6)GlcNAcβ1-2Manα1-6(Siaα2-3Galβ1-4GlcNAcβ1-2Manα1-3)Manβ1-4GlcNAcβ1-4(Fucα1-6)GlcNAc. [ABSTRACT FROM AUTHOR]

B-cell precursor (BCP) leukemia cells infiltrate into peripheral organs and the disease often relapses. Inhibition of tissue infiltration may improve the treatment outcome of BCP-leukemia patients. Selectin ligand has been suggested to play an important role in the infiltration of leukemia cells. However, the regulation mechanisms and involvement in tissue infiltration of selectin ligand expression in BCP-leukemia cells are not fully understood. In this study, we report that BCP-leukemia cells express selectin ligand on O-sialoglycoproteins. Core 2 β1,6-N-acetylglucosaminyltransferase-1 (C2GnT-1) is mainly expressed in BCP-leukemia cells. Transfection of the antisense C2GnT-1 cDNA resulted in a significant reduction of either selectin ligand expression or selectin-dependent cell adhesion in BCP-leukemia cell line KM3 cells. Migration ability into mouse peripheral organs was reduced significantly in the antisense transfectant. These findings suggest that C2GnT-1 regulates selectin ligand expression. Downregulation of the selectin ligand expression level inhibits tissue infiltration of BCP-leukemia cells. C2GnT-1 may be a candidate of therapeutic target for the inhibition of infiltration of leukemia cells.Leukemia (2005) 19, 1934–1940. doi:10.1038/sj.leu.2403951; published online 22 September 2005 [ABSTRACT FROM AUTHOR]

Synthesis and antigenic reactivity of 6- O-sulfo sialylparagloboside (SPG) and sialyl Lewis X (sLe X) neo-glycolipids containing lactamized neuraminic acid are described. The suitably protected GlcNAc-β (1 → 3)-Gal-β (1 → 4)-GlcOSE derivative was glycosylated with NeuTFAc-α (2 → 3)-Gal imidate to give NeuTFAc-α (2 → 3)-Galβ (1 → 4)-GlcNAc-β (1 → 3)-Gal-β (1 → 4)-GlcOSE pentasaccharide. The partial N, O-deacylation in the NeuTFAc-α (2→3)-Gal part afforded N-deacetylated SPG derivative which was converted to the desired oligosaccharide containing lactamized neuraminic acid. Similar treatment of the sLeX hexasaccharide derivative, NeuTFAc-α (2 → 3)-Gal-β (1 → 4) [Fuc-α (1 →3)]-GlcNAc-β (1 → 3)-Gal-β (1 → 4)-GlcOSE, gave the key hexasaccharide intermediate containing lactamized neuraminic acid. These suitably protected SPG and sLex oligosaccharides were converted stepwise into the desired neo-glycolipids (GSC-551 and GSC-552) by the coupling with 2-(tetradecyl)hexadecanol, 6- O-sulfation at C-6 of the GlcNAc residure, and complete deprotection. Both lactamized-sialyl 6- O-sulfo SPG (GSC-551) and sLex (GSC-552) neo-glycolipids were clearly recognized with G159 monoclonal antibody showing that both the lactamized neuraminic acid and the 6- O-sulfate at C-6 of GlcNAc would be involved in the G159-defined determinant. However, the Fuc residue and the lipophilic (ceramide) part may not be critical for this recognition. Published in 2005 [ABSTRACT FROM AUTHOR]

Cell adhesion mediated by selectins and their carbohydrate ligands, sialyl Lewis X and sialyl Lewis A, figures heavily in cancer metastasis. Expression of these carbohydrate determinants is markedly enhanced in cancer cells, but the molecular mechanism that leads to cancer-associated expression of sialyl Lewis X/A has not been well understood. Results of recent studies indicated involvement of two principal mechanisms in the accelerated expression of sialyl Lewis X/A in cancers; ‘incomplete synthesis’ and ‘ neosynthesis.’ As to ‘incomplete synthesis,’ we have recently found further modified forms of sialyl Lewis X and sialyl Lewis A in non-malignant colonic epithelium, which have additional 6-sulfation or 2 → 6 sialylation. The impairment of GlcNAc 6-sulfation and 2 → 6 sialylation upon malignant transformation leads to accumulation of sialyl Lewis X/A in colon cancer cells. Epigenetic changes such as DNA methylation and/or histone deacetylation are suggested to lie behind such incomplete synthesis. As to the mechanism called ‘ neosynthesis,’ recent studies have indicated that cancer-associated alterations in the sugar transportation and intermediate carbohydrate metabolism play important roles. Cancer cells are known to exhibit a metabolic shift from oxidative to elevated anaerobic glycolysis (Warburg effect), which is correlated with the increased gene expression of sugar transporters and glycolytic enzymes induced by common cancer-specific genetic alterations. The increased sialyl Lewis X/A expression in cancer is a link in the chains of these events because our recent results indicated that these events accompany transcriptional induction of a set of genes closely related to its expression. Published in 2004. [ABSTRACT FROM AUTHOR]

The blocking potency of P- and L-selectin was studied for certain small molecule mannosides and their polyacrylamide (PAA, 30 kDa) conjugates in comparison to SiaLex and fucoidan. Two experimental systems were used: (1) solid phase static assay based on recombinant selectins, and (2) P-selectin dependent rat peritoneal inflammation. βMan-SC6H4NO2- p was four times more potent P-selectin inhibitor as compared to SiaLex. Docking of this molecule onto the P-selectin carbohydrate-binding site demonstrated that a nitro group enabled an electrostatic interaction with residue Lys 84, while the phenyl ring and the CH2 at C-6 contacted the CH2 groups of the same Lys residue. In vivo, βMan-SC6H4NO2- p blocked experimental inflammation better than SiaLex, but significantly lower than fucoidan. In vitro Man-polyacrylic acid conjugates appeared to be very potent inhibitors comparable to fucoidan, uncharged Man-PAA proved rather active, comparable to SiaLex-PAA both in vitro, and in vivo, whereas mannan did not display any P-selectin blocking effect. Published in 2004. [ABSTRACT FROM AUTHOR]

Recently, we reported that tethering and rolling of neutrophils in shear flow over a substrate of E-selectin signals activation of $$\beta _2$$ -integrins and firm adhesion via an intracellular signaling pathway involving phosphorylation of p38 MAP kinase. In the current study the objective was to examine the molecular mechanisms and shear dependence underlying activation and adhesion of $$\beta _2$$ -integrin during shear-induced collisions between human neutrophils and murine B cells (300.19) transfected to express either E-selectin or L-selectin. Three separate parameters of cell activation were assessed over the time course of application of a defined shear field to heterotypic cell suspensions in a cone–plate viscometer. These were the two-body collision doublet lifetime and capture efficiency, surface upregulation of CD11b/CD18, and tyrosine phosphorylation of p38 MAP kinase. The data indicate that neutrophil adhesion to E-selectin expressing 300.19 cells occurs with a fourfold higher efficiency of firm adhesion than do collisions with L-selectin or parent control cells. Visual analysis of aggregation in a transparent cone–plate rheoscope revealed that the lifetime and efficiency of doublet formation increased four-fold as the applied shear stress increased. Neutrophil tethering via E-selectin was associated with rapid activation as indicated by upregulation of surface CD11b/CD18 and phosphorylation of p38 MAP kinase within seconds of application of shear. Activation greatly exceeded that observed for neutrophils sheared alone or with B cells expressing L-selectin. A distinct dependence of activation on the magnitude of the shear rate suggests a coupling between the fluid mechanical effects of shear and signaling of neutrophil adhesion. © 2002 Biomedical Engineering Society. PAC2002: 8717-d, 8719Tt [ABSTRACT FROM AUTHOR]

Leukocytes enter specific ovarian areas at a precisely defined moment, influencing cyclically changing structures such as follicles and corpora lutea. As yet, no studies have been published on the trafficking mechanisms involving the interaction between adhesion molecules on endothelial cells (ECs) and those on leukocytes. First, antibodies against human adhesion molecules were examined by flow cytometry with the aim of identifying the same bovine antigen. Western blot analysis and immunoprecipitation revealed that the molecules had the same molecular weight as their human counterparts. Afterwards, we investigated the distribution of these antigens in various ovarian stages using immunohistology. Among the molecules, P-selectin (CD62P) and L-selectin (CD62L) showed stage-dependent expression, and were thus examined further. In the preovulatory follicle, microvascular ECs were negative for CD62P. Few of the leukocytes expressed CD62L. In a freshly ruptured follicle, CD62P expression was found in the dilated vessels of the former thecal layer. Simultaneously, a large proportion of the rapidly increased numbers of leukocytes, mainly eosinophils, located around the microvessels of the outer thecal layer expressed CD62L. In the early corpus luteum development stage, CD62L showed peak expression with 70%–80% positive cells compared to leukocytes. In the secretory stage, the septal venules showed a consistent, but now weak, staining for CD62P. Few leukocytes expressed CD62L. During regression, the total number of leukocytes, now representing macrophages, increased significantly, but the proportion of CD62L-positive cells remained constant. In summary, we found a strong correlation of CD62P expression on activated ECs and the appearance of CD62L-positive leukocytes in the early corpus luteum development stage, suggesting the participation of both selectins in the migration of eosinophils under physiological conditions. [ABSTRACT FROM AUTHOR]

Three differentially expressed selectin genes (SELE, SELP, and SELL), important in the initial stages of leukocyte extravasation, have been reported in mammals. All three genes map close to the chemokine SCYC1 (small inducible cytokine subfamily C, member 1) in a large conserved chromosomal segment that extends from RXRG (retinoic acid receptor, gamma) to TNNT2 (troponin T2) on Chromosome (Chr) 1 in both human and mouse. In the mouse, we demonstrate that Sele is flanked by Prrx1 (paired-related homeobox gene 1) and Scyc1 and define the order of, and distances between, loci as centromere–Prrx1–(0.7±0.7 cM)–Sele–(1.2±0.9 cM)–Scyc1–telomere. In the chicken, we isolated BAC clones containing PRRX1, SELE, and SCYC1 and positioned them by fluorescent in situ hybridization. SELE and PRRX1 mapped to the short arm of chicken Chr 8 and SCYC1 mapped to the region equivalent to 1q11–1q13 on the long arm of chicken Chr 1. The location of SELE on chicken Chr 8 was independently established by linkage analysis of COM0185, an (AT)16 microsatellite locus identified in a BAC clone that contained SELE. COM0185 was linked to several loci that mapped to one end of chicken Chr 8, with the order of loci, and genetic distances (in cM) between them defined as MSU0435, MSU0325–(7.8±3.7)–COM0185–(5.8±3.2)–ROS0338–(9.6±4.0)–ABR0322–(3.8±2.6)–GLUL. We have therefore positioned an evolutionary breakpoint in mammals and chickens between SELE and SCYC1. Furthermore, comparative mapping analysis of the RXRG–TNNT2 chromosomal segment that is conserved on human and mouse Chr 1 indicates that it is divided into four segments in the chicken, each of which maps to a different chromosome. [ABSTRACT FROM AUTHOR]

A new method of analyzing in vivo measurements of leukocyte WBC rolling along venular endothelium (EC) has been developed to extract insightful information on the dynamics of WBC–EC bond formation and disruption. The rolling velocity of WBCs was obtained by intravital microscopy of rat mesenteric venules. For the “spontaneous” rolling observed following exteriorization of the mesentery, we estimated that the average distance between clusters of adhesion bonds which tether a rolling cell to the venular wall was about 2 μm, and that the average lifetime of a bond cluster at the trailing edge of the rolling cell, from its exposure to the tensile force to its release, was on the order of 0.05 s. Both the inter-cluster distance and the lifetime were significantly reduced by treatments with the chemoattractant N-formyl-methionyl-leucyl-phenylalanine and the cytokine interleukin-1, while the average lifetime of the stretched bond clusters was not significantly changed by treatment with the cytoskeleton-modifying agents cytochalasin B and colchicine. Each of the four treatments significantly reduced the heterogeneity in the cell rolling velocity, presumably by the selective recruitment of WBC subsets from the circulating WBC population or by a reduction in the heterogeneity of endothelial adhesiveness. These results were analyzed in the context of in vitro data in the literature on molecular bonds of cell adhesion. The findings suggest that, in the case of “spontaneous” rolling, there are on average approximately 2–3 clusters of adhesion bonds between a rolling cell and the vessel wall, and approximately five bonds in each cluster. © 2001 Biomedical Engineering Society. PAC01: 8719Uv, 8717-d, 8714Ee, 8715By [ABSTRACT FROM AUTHOR]

Leukocyte inter actions with vascular endothelium are high lyorchestrated processes that include the capture of free-flow ing leukocytes from the blood with subsequent leukocyte rolling, arrest, firm adhesion, and ensuing diapedesis. These interactions occur under high shear stresses within venules and depend on multiple families of adhesion molecules. Many of the adhesion molecules involved are now identified. In addition, precise mechanisms underlying their regulation and our understanding of how different families of adhesion molecules work together is becoming clearer. Specifically, leukocyte/endothelial cell interactions such as capture, rolling, and firm adhesion can no longer beviewed asoccurring in discrete steps mediated by individual families of adhesion molecules, but rather as a series of overlapping synergistic interactions among adhesion molecules resulting in an adhesion cascade. Although long thought to be mediated by distinct adhesion pathways, overlapping adhesion cascades mediate normal lymphocyte recirculation to peripheral lymphoid tissues and inflammation-induced leukocyte migration. These cascades thereby direct leukocyte migration, which is essential for the generation of effective inflammatory responses and the development of rapid immune responses. [ABSTRACT FROM AUTHOR]

Objective: To investigate the relationship between cytokines and the inflammatory responses in patients with out-of-hospital cardiac arrest, we examined the changes of cytokines as well as alterations in the markers of neutrophil activation, platelet and endothelial activation, and endothelial injury.Design: Prospective, cohort study.Setting: General intensive care unit of a tertiary care center.Patients and Participants: 26 out-of-hospital cardiac arrest patients were classified into two groups: those who achieved return of spontaneous circulation (ROSC) (n = 10) and those with no ROSC (n = 16). Eight normal healthy volunteers served as control subjects.Measurements and Results: Serial levels of soluble L-selectin (sL-selectin), soluble P-selectin (sP-selectin), neutrophil elastase, and soluble thrombomodulin were measured during and after cardiopulmonary resuscitation (CPR). Serial levels of tumor necrosis factor alpha (TNFalpha) and interleukin-1beta (IL-1beta) were also measured. We could not find any elevations in either cytokine during the study period. In both groups, sP-selectin levels were significantly higher than those in control subjects from the time of arrival at the emergency department to 24 h after admission. sL-selectin levels in the two groups were markedly lower compared to those in control subjects at all sampling points. In patients with ROSC, cardiac arrest and CPR led to an increase in the levels of neutrophil elastase and soluble thrombomodulin that peaked 6 h or 24 h after arrival at the emergency department. No statistical differences in the levels of the two selectins, neutrophil elastase, and soluble thrombomodulin between the two groups were found during CPR.Conclusions: Out-of-hospital cardiac arrest and CPR induces platelet, neutrophil, and endothelial activation and is associated with endothelial injury. Inflammatory cytokines may not have an important role in human whole-body ischemia-reperfusion injury. [ABSTRACT FROM AUTHOR]

Panosialins A and B were isolated as inhibitors of an α1,3-fucosyltransferase, Fuc-TVII, which is a key enzyme in the biosynthesis of selectin ligands, from culture broth of Streptomyces sp. Panosialins A and B inhibited the Fuc-TVII activity with IC50 values of 4.8 and 5.3 μg/ml, respectively. Panosialin A suppressed expression of selectin ligands on U937 cells, and inhibited the cell adhesion to immobilized E-selectin-immunoglobulin. Panosialins are the first reported Fuc-TVII inhibitors which can suppress the biosynthesis of selectin ligands and then inhibit selectin-mediated cell adhesion. [ABSTRACT FROM AUTHOR]

To clarify the acceptor specificity of Fuc-TVII, its activity toward various analogs of a 2-(trimethylsilyl)ethyl α2,3-sialyl lacto-N-neotetraose, an acceptor for both Fuc-TVII and Fuc -TVI, was examined in comparison with that of Fuc-TVI. Fuc-TVII required three portions of α2,3-sialylated type-2 oligosaccharide structures (i.e., the hydroxyl group at C-4 of Gal, the hydroxyl group at C-3 of GlcNAc, and the carbonylamino group at C-2 of GlcNAc) for its acceptor recognition. Fuc-TVI required the carbonylamino group at C-2 of GlcNAc for its acceptor recognition. Fuc-TVI I showed higher affinity toward two analogs, in which the hydroxyl group at C-6 of GlcNAc has been deoxygenated and the acetamide group of N-acetylneuraminic acid has been replaced with a glycolylamino group, respectively, than that toward the original compound. On the other hand, Fuc-TVI showed higher affinity toward an analog, in which the acetamide group of GlcNAc has been modified with a lauroylamino group, than that toward the original compound. Analysis involving mass spectrometry confirmed that both Fuc-TVII and Fuc-TVI could fucosylate these three analogs to yield sialyl Lewis x derivatives. [ABSTRACT FROM AUTHOR]

Extravasation from the blood of malignant tumour cells that form metastasis and leukocytes that go into tissues require contact between selectins and their sialyl Lewis x and sialyl Lewis a (sLex and sLea respectively) decorated ligands. Endothelial cells have been shown to express sLex epitopes in lymph nodes and at sites of inflammation, and this is crucial for the selectin-dependent leukocyte traffic. Besides the ability to synthesize sLex on sialylated N-acetyllactosamine via the action of α(1,3)fucosyltransferase(s), endothelial cells can also degrade sLex to Lewis x through the action of α(2,3)sialidase(s). In addition, several epithelial tumors possess the machinery to synthesize sLex, which facilitates their adhesion to endothelial E- and P-selectin. [ABSTRACT FROM AUTHOR]

The carbohydrate determinants, sialyl Lewis A and sialyl Lewis X, which are frequently expressed on human cancer cells, serve as ligands for a cell adhesion molecule of the selectin family, E-selectin, which is expressed on vascular endothelial cells. These carbohydrate determinants are involved in the adhesion of cancer cells to vascular endothelium and thus contribute to hematogenous metastasis of cancer. The initial adhesion mediated by these molecules triggers activation of integrin molecules through the action of several cytokines and leads to the extravasation of cancer cells. Cancer cells also produce humoral factors that facilitate E-selectin expression on endothelial cells. The degree of expression of the carbohydrate ligands at the surface of cancer cells is well correlated with the frequency of hematogenous metastasis and prognostic outcome of patients with cancers. The alteration of glycosyltransferase activities that leads to the enhanced expression of these carbohydrate ligands on cancer cell surface are currently being investigated. [ABSTRACT FROM AUTHOR]

No abstract Abbreviations: Sia, sialic acid, type unspecified; Tn antigen, GalNAcα 1-O-Ser/Thr; T antigen, Galβ1-3GalNAcα-O-Ser/Thr; Sialyl LewisX, Siaα2-3Galβ1-4(Fucα1-3)GlcNAc; Sialyl Lewisa, Siaα2-3Galβ1-3(Fucα1-4)GlcNAc; Sialyl-Tn antigen, Siaα2-6GalNAcα1-O-Ser/Thr; FucT, fucosyltransferase; ST, sialyltransferase. [ABSTRACT FROM AUTHOR]

Employing a new procedure, we established many monoclonal antibodies (mAbs) which inhibit E- or P-selectin-dependent cell adhesion. One of these mAbs is capable of staining selectin in paraffin-embedded histological sections. The procedure is based on immunization of BALB/c mice with irradiated mouse myeloma NS-1 cells (syngeneic HAT-sensitive fusion partner cells) transfected with cDNA encoding human E- or P-selectin. Resulting NS-1 transfectant cells permanently express human E- or P-selectin as immunogen. The mAbs are useful for detecting selectins by flow cytometric and immunohistological methods, and for inhibiting selectin-dependent adhesion in experimental models. In contrast, the majority of anti-selectin mAbs previously established do not have these capabilities. Abbreviations: Ig, immunoglobulin; mAb, monoclonal antibody [ABSTRACT FROM AUTHOR]

Complement control protein (CCP) modules, or short consensus repeats (SCR), exist in a wide variety of complement and adhesion proteins, principally the selectins. We have predicted the three-dimensional structure of a CCP module based upon secondary structural information derived by two-dimensional NMR [Barlow et al. (1991), Biochemistry 30, 997–1004]. Accordingly, the CCP is predicted to contain seven β-strands with extensive hydrogen-bonding interactions, and shows a compact, globular structure. Comparison of this model to the X-ray structure of a kringle domain suggests that the CCP unit is more compact than a kringle structure, and that despite their similarities in size and disulfide bond format, the two are not homologous. Although the function of CCP domains is unknown, it is hoped that the structural model presented herein will facilitate further inquiry into how they contribute to so many systems of biological importance. [ABSTRACT FROM AUTHOR]

Metastasis is one of the most devastating aspects of cancer. It is a complex multistep processes that results in spread of tumorigenic cells to secondary sites in various organs. The actual events that are involved in metastasis are the subject of several recent reviews [1-3]. Upon growth of neoplastic cells beyond a certain mass (2 mm in diameter) an extensive vascularization through angiogenesis occurs. The new capillary network provides a supply of nutrients and gas exchange that allows further growth and development of the tumor mass. The network of the blood vessels also provides an entry site into the circulation for the neoplastic cells that detach from the tumor mass. Only a small percentage of circulating tumor cells (< 0.01%) survive travel in the circulation and arrest in the capillary beds of distant organs, extravasate and proliferate within the organ parenchyma producing a successful metastasis [1]. Vasculature plays an important role in several steps of the metastatic process; 1) at the site of metastasis, vessels capture the cancer cell and provide the entry route into the secondary organ, and 2) through angiogenesis, vascular endothelial cells provide the supply of nutrients for the growth of the primary tumor mass and the route of intravasation. The lining of all blood vessels are covered with endothelial cells which play an active role in both processes. The metastatic properties of cancer cells have been extensively studied. Here, we will discuss the role of endothelial cells in the metastatic process with focus on their interaction with cancer cells at the site of extravasation. [ABSTRACT FROM AUTHOR]

Two anti-sialyl Lewis X (sLe X ) monoclonal antibodies, mAb FH6 and mAb KM93, were analyzed by flowcytometry for their ability to bind to 16 human colon carcinoma cells. The binding profiles of these twoanti-sLe X monoclonal antibodies did not correspond to each other. Three of the cell lines were reactive withmAb FH6 but not with mAb KM93. These three cell lines did not adhere to Chinese hamster ovary cellsthat were stably transfected with human E-selectin cDNA in an E-selectin-dependent manner. In contrast,almost all human colon carcinoma cell lines that bound to mAb KM93 adhered to cells that expressedE-selectin. These results suggest that a subtype of sLe X carbohydrate epitopes recognized by mAb FH6 donot always function as ligands for E-selectin.© Kluwer Academic Publishers [ABSTRACT FROM AUTHOR]

Objective:Controlled ovarian hyperstimulation (COH) is apparently a key factor in the success of in vitro fertilization-embryo transfer. One of the major complications of COH is severe ovarian hyperstimulation syndrome (OHSS), which may be attributable to a massive increase in systemic inflammatory cytokines or to neutrophil activation. The aim of the present review was to investigate the role of COH in the induction of an inflammatory response.Methods:Major studies that have reported on the association between COH and inflammation were identified through MEDLINE searches and the published literature.Results:Several inflammatory mediators, namely, C-reactive protein and leukocyte and endothelial selectins, showed a significant increase after human chorionic gonadotropin (hCG) administration in vivo, reflecting an inflammatory state, and neutrophil and endothelial activation, respectively. On the other hand, hCG showed a direct depressive effect on mononuclear cells in vitro. Because the development of OHSS almost always follows hCG administration, the negative effect of hCG on peripheral mononuclear cells indicates that it probably causes OHSS by an indirect mechanism.Conclusion:We suspect that hCG stimulates the ovaries to produce and secrete a still unknown intermediate factor, which in turn activates inflammatory processes that may lead to an increase in capillary permeability. [ABSTRACT FROM PUBLISHER]