Intercellular adhesion molecule 1 and selectin l play crucial roles in ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease that primarily affects the mucosal layer of the colon (large intestine). However, the relationship between Intercellular Adhesion Molecule-1 (ICAM1), SELL and UC is unclear. The UC datasets, GSE87466 and GSE36807, were downloaded from the gene expression omnibus database. The R package limma was utilized to identify differentially expressed genes (DEGs). Weighted gene co-expression network analysis was conducted. The construction and analysis of protein-protein interaction network, functional enrichment analysis, gene set enrichment analysis, and comparative toxicogenomics database analysis were performed. TargetScan was employed to screen miRNAs regulating central DEGs. Western blot (WB) was used to verify. A total of 2118 DEGs were identified in our study. Gene ontology analysis indicated their enrichment primarily in immune system processes, cellular responses to chemical stimuli, responses to organic substances, responses to external stimuli, and immune responses. Kyoto Encyclopedia of Genes and Genomes analysis revealed that the target cells were mainly enriched in chemokine signaling pathways and TNF signaling pathways. Gene set enrichment analysis enrichment analysis showed significant enrichment in chemokine signaling pathways and cell adhesion molecules. In the Metascape enrichment project, gene ontology terms included regulation of cell activation and positive regulation of immune response. Through the construction and analysis of a protein-protein interaction network, we identified 11 core genes (ICAM1, SELL, CD44, CD40, CCR7, CXCL8, CD19, CCL4, CD274, IL7R, IL1B). We found that the core genes (ICAM1, SELL) were highly expressed in UC samples and lowly expressed in normal samples, suggesting their potential regulatory roles in UC. These core genes were associated with lymphoproliferative disorders, inflammation and necrosis. WB results confirmed the high expression of ICAM1 and SELL in UC. ICAM1 and SELL are highly expressed in UC, and the higher the ICAM1 and SELL genes, the worse the prognosis.

A Sialylated-Bortezomib Prodrug Strategy Based on a Highly Expressed Selectin Target for the Treatment of Leukemia or Solid Tumors.

PURPOSE: This study aimed to explore the potential of sialic acid - related selectin targeting strategy in the treatment of leukemia and some solid tumors. We expected it could "actively" bind tumor cells and kill them, reducing non-specific toxicity to normal cells. METHODS: BOR-SA prodrug was synthesized by reacting an ortho-dihydroxy group in SA with a boronic acid group in BOR. Two kinds of leukemia cells (RAW264.7 and HL60 cells), one solid sarcoma cell model (S180 cells) and their corresponding normal cells (monocytes (MO), neutrophil (NE) and fibroblast (L929)) were selected for the in vitro cell experiments (cytotoxicity, cellular uptake, cell cycle and apoptosis experiments). The S180 tumor-bearing Kunming mice model was established for anti-tumor pharmacodynamic experiments. RESULTS: In vitro cell assay results showed that uptake of BOR-SA by HL60 and S180 cells were increased compared with the control group. BOR-SA induced a lower IC50, higher ratio of apoptosis and cell cycle arrest of tumor cells. In vivo anti-S180 tumor pharmacodynamics experiments showed that mice in the BOR-SA group had higher tumor inhibition rate, higher body weight and lower immune organ toxicity compared with the control group. CONCLUSIONS: sialic acid-mediated selectin targeting strategy may have great potential in the treatment of related tumors.

Lack of functional selectin-ligand interactions enhances innate immune resistance to systemic Listeria monocytogenes infection.

Selectin-ligand interactions are important for leukocyte homing and functionality. The roles of selectin-ligand interactions in modulating immunity to intracellular infections are not completely understood. Mice lacking the expression of fucosyltransferase-IV and -VII (Fucosyltransferase-IV and -VII double knockout, FtDKO) exhibit deficient functionality of selectin-ligand interactions. We addressed the kinetics of infection and immunity to Listeria monocytogenes (LM), an intracellular pathogen, in FtDKO mice. These mice exhibited enhanced ability to clear infection and increased survival to a lethal dose of LM infection relative to wild-type (WT) C57BL/6J controls. This was associated with increased levels of neutrophils, monocytes, and dendritic cells (DCs) in the blood and/or infected organs. Adoptive transfer of bone marrow (BM) cells from FtDKO mice to WT mice resulted in enhanced neutrophil numbers and improved clearance of LM bacteria in recipients. In vivo depletion of myeloid innate immune cells, particularly neutrophils, monocytes, macrophages, and DCs, using anti-Ly-6G (RB6-8C5) monoclonal antibody, reduced the ability of FtDKO mice to curtail LM infection. Nevertheless, depletion using anti-Ly-6G (1A8) known to exclusively deplete neutrophils did not abrogate increased resistance of FtDKO mice to LM infection, suggesting a role for other myeloid innate immune cells in this model. Examination of BM hematopoietic progenitors through flow cytometry and cell culture colony-forming unit assay showed increased frequencies of granulocyte-macrophage progenitors in FtDKO relative to WT mice, Overall, our results indicate that functional selectin ligand deficiency enhances innate immune-mediated resistance to systemic LM infection despite defective leukocyte migration and lymphocyte homing.

Role of selectins and their ligands in human implantation stage.

Selectins are a family of calcium-dependent, type I transmembrane, carbohydrate-binding glycoproteins. Selectins and their ligands are not only involved in physiological processes such as leukocyte homing and pathological processes such as cancer, but also play an essential role in the human implantation. L-selectin and its ligands participate in the adhesion of the blastocyst to the endometrium at the maternal-fetal interface. P-selectin and E-selectin are involved in immune recognition of maternal decidua to the embedded embryo as well as trophoblast migration within decidual spiral arterioles. Moreover, altered expression of selectins and their ligands are found to be associated with some abnormal pregnancies and infertilities. This review focuses on the current progress of research on the role of selectins and their ligands in the human implantation process.

Zooming in on selectins in cancer.

Selectins are involved in leukocyte and cancer cell trafficking, which can be targeted with drugs and nanoparticles (Shamay et al., this issue).

The neutrophil function and lymphocyte profile of milk from bovine mammary glands infected with Streptococcus dysgalactiae.

Streptococcus dysgalactiae is a bacterium that accounts for a notable proportion of both clinical and subclinical intramammary infections (IMIs). Thus, the present study explores the function of milk neutrophils and the lymphocyte profile in mammary glands naturally infected with Streptococcus dysgalactiae. Here, we used 32 culture-negative control quarters from eight clinically healthy dairy cows with low somatic cell counts and 13 S. dysgalactiae-infected quarters from six dairy cows. Using flow cytometry, we evaluated the percentage of milk monocytes/macrophages and neutrophils, expression of CD62L, CD11b and CD44 by milk neutrophils, the levels of intracellular reactive oxygen species (ROS) production and phagocytosis of Staphylococcus aureus by milk neutrophils, and neutrophil viability. Furthermore, the percentages of B cell (CD21(+)) and T lymphocyte subsets (CD3(+)/CD4(+)/CD8(-); CD3(+)/CD8(+)/CD4(-); and CD3(+)/CD8(-)/CD4(-)), and the expression of CD25 by T milk lymphocytes (CD3(+)) and T CD4(+) milk cells were also assessed by flow cytometry using monoclonal antibodies. The present study showed a higher SCC and percentage of milk neutrophils, and a decrease in the percentage of milk monocytes/macrophages from S. dysgalactiae-infected quarters when compared to uninfected ones. We also observed a higher expression of CD11b by milk neutrophils and a tendency toward a decrease in neutrophil apoptosis rate in S. dysgalactiae-infected quarters. In addition, the S. dysgalactiae-infected quarters had higher percentages of milk T cells (CD3(+)) and their subset CD3(+)CD8(+)CD4(-) cells. Overall, the present study provided new insights into S. dysgalactiae IMIs, including distinct lymphocyte profiles, and a tendency toward an inhibition of apoptosis in milk neutrophils.

Differential Features of AIRE-Induced and AIRE-Independent Promiscuous Gene Expression in Thymic Epithelial Cells.

Establishment of self-tolerance in the thymus depends on promiscuous expression of tissue-restricted Ags (TRA) by thymic epithelial cells (TEC). This promiscuous gene expression (pGE) is regulated in part by the autoimmune regulator (AIRE). To evaluate the commonalities and discrepancies between AIRE-dependent and -independent pGE, we analyzed the transcriptome of the three main TEC subsets in wild-type and Aire knockout mice. We found that the impact of AIRE-dependent pGE is not limited to generation of TRA. AIRE decreases, via non-cell autonomous mechanisms, the expression of genes coding for positive regulators of cell proliferation, and it thereby reduces the number of cortical TEC. In mature medullary TEC, AIRE-driven pGE upregulates non-TRA coding genes that enhance cell-cell interactions (e.g., claudins, integrins, and selectins) and are probably of prime relevance to tolerance induction. We also found that AIRE-dependent and -independent TRA present several distinctive features. In particular, relative to AIRE-induced TRA, AIRE-independent TRA are more numerous and show greater splicing complexity. Furthermore, we report that AIRE-dependent versus -independent TRA project nonredundant representations of peripheral tissues in the thymus.

Role of siglecs and related glycan-binding proteins in immune responses and immunoregulation.

Virtually all cells and extracellular material are heavily decorated by various glycans, yet our understanding of the structure and function of these moieties lags behind the understanding of nucleic acids, lipids, and proteins. Recent years have seen a tremendous acceleration of knowledge in the field of glycobiology, revealing many intricacies and functional contributions that were previously poorly appreciated or even unrecognized. This review highlights several topics relevant to glycoimmunology in which mammalian and pathogen-derived glycans displayed on glycoproteins and other scaffolds are recognized by specific glycan-binding proteins (GBPs), leading to a variety of proinflammatory and anti-inflammatory cellular responses. The focus for this review is mainly on 2 families of GBPs, sialic acid-binding immunoglobulin-like lectins (siglecs) and selectins, that are involved in multiple steps of the immune response, including distinguishing pathogens from self, cell trafficking to sites of inflammation, fine-tuning of immune responses leading to activation or tolerance, and regulation of cell survival. Importantly for the clinician, accelerated rates of discovery in the field of glycoimmunology are being translated into innovative medical approaches that harness the interaction of glycans and GBPs to the benefit of the host and might soon lead to novel diagnostics and therapeutics.

Endothelial cells recruit macrophages and contribute to a fibrotic milieu in bleomycin lung injury.

Systemic sclerosis (SSc) is a systemic autoimmune disease that causes inflammation, vasculopathy, and fibrosis of the skin and internal organs. One of the most severe complications of SSc involves the development of pulmonary fibrosis. Endothelial cell injury precedes the development of fibrosis, and is believed to be an initiating event. Therefore, we aimed to characterize the role of endothelial cells in the progression of pulmonary fibrosis, using a well-established bleomycin (BLM) model of pulmonary fibrosis. Endothelial cells were isolated by cell sorting, and the analysis of gene expression was performed with quantitative RT-PCR. Endothelial injury was induced between the first and second week, as shown by the elevated expression of the vascular injury markers matrix metallopeptidase-12 and von Willebrand factor. After injury, endothelial activation was indicated by the up-regulation of selectins, CCL chemokines, and inflammatory mediators, including complement anaphylatoxin receptors (C3aR and C5aR), oncostatin M, and leukemia inhibitory factor. The endothelial cell overexpression of fibrotic mediators, including connective tissue growth factor, plasminogen activator inhibitor-1, osteopontin, fibronectin, and fibroblast specific protein-1, was observed in the second and fourth weeks. This study suggests that endothelial cells actively contribute to the disease process via multiple mechanisms, including the recruitment of inflammatory cells and the establishment of a profibrotic environment during the development of BLM-induced pulmonary fibrosis.

Interactions between endothelial selectins and cancer cells regulate metastasis.

The selectins: E-selectin, P-selectin, and L-selectin are adhesion molecules that are crucial for binding of circulating leukocytes to vascular endothelium during the inflammatory response to injury or infection. Accumulated evidence indicates that selectins regulate adhesion of circulating cancer cells to the walls of blood vessels. Selectin ligands are transmembrane glycoproteins expressed on leukocytes and cancer cells that promote bond formations with selectins to mediate inflammatory processes. Selectins and selectin ligands also participate in signal transduction to regulate diverse cellular functions. Sialyl Lewis X (sLe(x)) and sialyl Lewis A (sLe(a)) tetrasaccharides are carbohydrate motifs displayed on protein or lipid scaffolds that are critical components of functional selectin ligands. Selectin binding to sLe(x) and sLe(a) present on colon, gastric, bladder, pancreatic, breast, and prostate carcinomas enhances distant organ metastasis. High expression of sialyl Lewis ligands on these cancers is significantly correlated with a poor post-operative prognosis. This review will focus on the roles of E-selectin and P-selectin in cancer progression. Understanding the role of selectins in cancer supports the development of novel selectin-based therapies to control metastasis.

Selectins promote tumor metastasis.

Cancer metastasis is facilitated by cell-cell interactions between cancer cells and endothelial cells in distant tissues. In addition, cancer cell interactions with platelets and leukocytes contribute to cancer cell adhesion, extravasation, and the establishment of metastatic lesions. Selectins are carbohydrate-binding molecules that bind to sialylated, fucosylated glycan structures, and are found on endothelial cells, platelets and leukocytes. There are three members of the selectin family: P-selectin expressed on activated platelets and endothelial cells, L-selectin present on leukocytes and E-selectin expressed on activated endothelial cells. Besides the accepted roles of selectins in physiological processes, such as inflammation, immune response and hemostasis, there is accumulating evidence for the potential of selectins to contribute to a number of pathophysiological processes, including cancer metastasis. Cancer cell interactions with selectins are possible due to a frequent presence of carbohydrate determinants--selectin ligands on the cell surface of tumor cells from various type of cancer. The degree of selectin ligand expression by cancer cells is well correlated with metastasis and poor prognosis for cancer patients. Initial adhesion events of cancer cells facilitated by selectins result in activation of integrins, release of chemokines and are possibly associated with the formation of permissive metastatic microenvironment. While E-selectin has been evaluated as one of the initiating adhesion events during metastasis, it is becoming apparent that P-selectin and L-selectin-mediated interactions significantly contribute to this process as well. In this review we discuss the current evidence for selectins as potential facilitators of metastasis.

The engagement of selectins and their ligands in colorectal cancer liver metastases.

he colonization of the liver by colorectal cancer (CRC) cells is a complicated process which includes many stages, until macrometastases occur. The entrapment of malignant cells within the hepatic sinusoids and their interactions with resident non-parenchymal cells are considered very important for the whole metastatic sequence. In the sinusoids, cell connection and signalling is mediated by multiple cell adhesion molecules, such as the selectins. The three members of the selectin family, E-, P- and L-selectin, in conjunction with sialylated Lewis ligands and CD44 variants, regulate colorectal cell communication and adhesion with platelets, leucocytes, sinusoidal endothelial cells and stellate cells. Their role in CRC liver metastases has been investigated in animal models and human tissue, in vivo and in vitro, in static and shear flow conditions, and their key-function in several molecular pathways has been displayed. Therefore, trials have already commenced aiming to exploit selectins and their ligands in the treatment of benign and malignant diseases. Multiple pharmacological agents have been developed that are being tested for potential therapeutic applications.

Roflumilast inhibits leukocyte-endothelial cell interactions, expression of adhesion molecules and microvascular permeability.

BACKGROUND AND PURPOSE: The present study addressed the effects of the investigational PDE4 inhibitor roflumilast on leukocyte-endothelial cell interactions and endothelial permeability in vivo and in vitro. EXPERIMENTAL APPROACH: In vivo, intravital video-microscopy was used to determine effects of roflumilast p.o. on leukocyte-endothelial cell interactions and microvascular permeability in rat mesenteric venules. In vitro, the effects of roflumilast N-oxide, the active metabolite of roflumilast in humans, and other PDE4 inhibitors on neutrophil adhesion to tumour necrosis factor alpha (TNFalpha)-activated human umbilical vein endothelial cells (HUVEC), E-selectin expression and thrombin-induced endothelial permeability was evaluated. Flow cytometry was used to determine the effect of roflumilast on N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced CD11b upregulation on human neutrophils. KEY RESULTS: In vivo, roflumilast, given 1 h before lipopolysaccharide (LPS), dose-dependently reduced leukocyte-endothelial cell interactions in rat mesenteric postcapillary venules. It also diminished histamine-induced microvascular permeability. Immunohistochemical analyses revealed that roflumilast prevented LPS-induced endothelial P- and E-selectin expression. In vitro, roflumilast N-oxide concentration-dependently suppressed neutrophil adhesion to TNFalpha-activated HUVEC and CD11b expression on fMLP-stimulated neutrophils. It also reduced TNFalpha-induced E-selectin expression on HUVEC, when PDE3 activity was blocked. HUVEC permeability elicited by thrombin was concentration-dependently suppressed by roflumilast N-oxide. While roflumilast N-oxide was as potent as roflumilast at inhibiting stimulated endothelial cell and neutrophil functions, both compounds were significantly more potent than the structurally unrelated PDE4 inhibitors, rolipram or cilomilast. CONCLUSIONS AND IMPLICATIONS: These findings further support earlier observations on the inhibition of inflammatory cell influx and protein extravasation by roflumilast in vivo.

Selectin polymorphisms and perinatal morbidity in low-birthweight infants.

BACKGROUND: Studies have shown an association between altered expression of selectins and premature birth, early sepsis and bronchopulmonary dysplasia. AIM: To investigate the possible link between functional polymorphisms of the E-, P- and L-selectin genes and perinatal morbidity. METHODS: We compared the genotype distribution of the E-selectin Ser128Arg, P-selectin Thr715Pro and L-selectin Pro213Ser polymorphisms in 125 low-birthweight singleton infants with those of 156 healthy term neonates. We also analysed the association of genotype with risk of sepsis and bronchopulmonary dysplasia. RESULTS: We found no association between E-selectin or P-selectin polymorphisms and premature birth, nor did we find any association between E-selectin or P-selectin and early postnatal sepsis or bronchopulmonary dysplasia. Carriers of the 213Ser L-selectin allele were found to be more prevalent in low-birthweight infants, particularly in those with bronchopulmonary dysplasia. We found no association between the L-selectin polymorphism and early postnatal sepsis. CONCLUSION: Our results underline the importance of L-selectin in perinatal pathology, but further studies are needed to evaluate the alteration of L-selectin levels in carriers of the 213Ser allele and their possible contribution to premature birth and bronchopulmonary dysplasia.

Therapeutic potential of selectin antagonists in psoriasis.

Psoriasis is a systemic chronic inflammatory disorder. One of the major characteristics is an excess of infiltration of inflammatory cells, mainly lymphocytes, into the skin. Because the adhesion family of selectins is suggested to play a relevant role in this process, selectins have emerged as an interesting target for drug discovery and development in psoriasis. Different strategies targeting selectins have been described. This review discusses these approaches and summarises the current development of selectin antagonists for the treatment of psoriasis. An expert opinion will give the authors' personal opinion about selectin antagonism in psoriasis and which approach might be preferable.

Emerging roles for ectodomain shedding in the regulation of inflammatory responses.

The multistep model of leukocyte recruitment to sites of inflammation has helped elucidate specific molecular cues for each of the individual steps. However, it is less clear how cells transition between the different steps and how the complex interactions are coordinately regulated. Once a leukocyte sticks to the endothelium, it only takes a few minutes to reach the subendothelial basement membrane, so the transitions and regulatory mechanisms must be rapid. We put forward the hypothesis that proteolytic shedding of cell surface proteins provides a mechanism to aid in the rapid transition of cells and coordinate the complex, multistep process of leukocyte recruitment in response to inflammatory stimuli. Support for this hypothesis is provided from analyses of disease states and from studies with protease inhibitors and genetically engineered mutations that prevent "ectodomain shedding" of cell surface proteins and consequently perturb the inflammatory response.

Requirement of IL-17 receptor signaling in radiation-resistant cells in the joint for full progression of destructive synovitis.

IL-17 is a proinflammatory cytokine suspected to be involved in inflammatory and autoimmune diseases such as rheumatoid arthritis. In the present study, we report that IL-17R signaling is required in radiation-resistant cells in the joint for full progression of chronic synovitis and bone erosion. Repeated injections of Gram-positive bacterial cell wall fragments (streptococcal cell wall) directly into the knee joint of naive IL-17R-deficient (IL-17R-/-) mice had no effect on the acute phase of arthritis but prevented progression to chronic destructive synovitis as was noted in wild-type (wt) mice. Microarray analysis revealed significant down-regulation of leukocyte-specific chemokines, selectins, cytokines, and collagenase-3 in the synovium of IL-17R-/- mice. Bone marrow (BM) chimeric mice revealed the need for IL-17R expression on radiation-resistant joint cells for destructive inflammation. Chimeric mice of host wt and donor IL-17R-/- BM cells developed destructive synovitis in this chronic reactivated streptococcal cell wall arthritis model similar to wt-->wt chimeras. In contrast, chimeric mice of host IL-17R-/- and donor wt BM cells were protected from chronic destructive arthritis similar as IL-17R-/- -->IL-17R-/- chimeras. These data strongly indicate that IL-17R signaling in radiation-resistant cells in the joint is required for turning an acute macrophage-mediated inflammation into a chronic destructive synovitis.

Increased primary tumor growth in mice null for beta3- or beta3/beta5-integrins or selectins.

Expression of alphavbeta3- or alphavbeta5-integrins and selectins is widespread on blood cells and endothelial cells. Here we report that human tumor cells injected s.c. into mice lacking beta3- or beta3/beta5-integrins or various selectins show enhanced tumor growth compared with growth in control mice. There was increased angiogenesis in mice lacking beta3-integrins, but no difference in structure of the vessels was observed by histology or by staining for NG2 and smooth muscle actin in pericytes. Bone marrow transplants suggest that the absence of beta3-integrins on bone marrow-derived host cells contributes to the enhanced tumor growth in beta3-null mice, although few, if any, bone marrow-derived endothelial cells were found in the tumor vasculature. Tumor growth also was affected by bone marrow-derived cells in mice lacking any one or all three selectins, implicating both leukocyte and endothelial selectins in tumor suppression. Reduced infiltration of macrophages was observed in tumors grown in mice lacking either beta3-integrins or selectins. These results implicate cells of the innate immune system, macrophages or perhaps natural killer cells, in each case dependent on integrins and selectins, in tumor suppression.

Combined anticoagulant and antiselectin treatments prevent lethal intravascular coagulation.

Widespread microvascular injury followed by vessel obstruction may lead to disseminated intravascular coagulation (DIC). We describe a murine model wherein leukocytes interacting with inflamed microvessels in vivo are activated by antibodies. Treatment of tumor necrosis factor alpha (TNF-alpha)-primed mice with anti-Ly-6G antibodies reproduced many of the features of septic or traumatic shock including microvessel obstruction and coagulation, severe vasculitis, respiratory difficulties, and vascular leakage. Mice lacking either E-selectin or P-selectin were protected from this reaction as were animals treated with a combination of either selectin-blocking antibodies and heparin or a selectin antagonist plus heparin. Combined blockade of leukocyte/platelet adhesion and coagulation may provide convincing protection in DIC.