We previously reported that versican, a large chondroitin/dermatan sulfate (CS/DS) proteoglycan, interacts through its CS/DS chains with adhesion molecules L-and P-selectin and CD44, as well as chemokines. Here, we have characterized these interactions further. Using a metabolic inhibitor of sulfation, sodium chlorate, we show that the interactions of the CS/DS chains of versican with L-and P-selectin and chemokines are sulfationdependent but the interaction with CD44 is sulfationindependent. Consistently, versican's binding to L-and P-selectin and chemokines is specifically inhibited by oversulfated CS/DS chains containing GlcA1-3Gal-NAc(4,6-O-disulfate) or IdoA␣1-3GalNAc(4,6-O-disulfate), but its binding to CD44 is inhibited by all the CS/DS chains, including low-sulfated and unsulfated ones. Affinity and kinetic analyses using surface plasmon resonance revealed that the oversulfated CS/DS chains containing GlcA1/IdoA␣1-3GalNAc(4,6-O-disulfate) bind directly to selectins and chemokines with high affinity (K d 21.1 to 293 nM). In addition, a tetrasaccharide fragment of repeating GlcA1-3GalNAc(4,6-Odisulfate) units directly interacts with L-and P-selectin and chemokines and oversulfated CS/DS chains containing GlcA1/IdoA␣1-3GalNAc(4,6-O-disulfate) inhibit chemokine-induced Ca 2؉ mobilization. Taken together, our results show that oversulfated CS/DS chains containing GlcA1/IdoA␣1-3GalNAc(4,6-O-disulfate) are recognized by L-and P-selectin and chemokines, and imply that these chains are important in selectin-and/or chemokine-mediated cellular responses.Proteoglycans are ubiquitous components of cell surface membranes, basement membranes, and extracellular matrices in various tissues. They belong to a family of macromolecules that consist of core proteins to which glycosaminoglycans (GAGs), 1 sulfated polysaccharides, are attached. GAGs are linear polysaccharides made up of disaccharide units composed of hexosamine and hexuronic acid (or hexose). They are classified into chondroitin sulfate (CS), dermatan sulfate (DS), heparin, heparan sulfate (HS), keratan sulfate (KS), and hyaluronic acid (HA). Because of the high sulfate and carboxyl group content of their GAG moieties, proteoglycans have strong negative charges. This property allows them to interact with a wide range of proteins, including growth factors, enzymes, cytokines, chemokines, lipoproteins, and adhesion molecules (1, 2). We previously showed that a large CS/DS proteoglycan, versican (also called PG-M), that was derived from a renal adenocarcinoma cell line, ACHN, interacts through its CS/DS chains with adhesion molecules such as L-and P-selectin and CD44 (3, 4), and various chemokines (5), all of which have been implicated in leukocyte trafficking. Versican possesses a hyaluronic acid-binding domain at its N terminus, a GAG attachment domain in the middle, and a set of epidermal growth factor-like, C-type lectin-like, and complement regulatory protein-like domains at its C terminus (6). Alternative splicing of the versican gene generates four ver...
E-selectin, an inducible cell adhesion molecule expressed on endothelial cells, mediates the rolling on endothelium of leukocytes expressing E-selectin ligands, such as neutrophils and activated T cells. Although previous studies using mice lacking P-selectin glycoprotein ligand-1 (PSGL-1) have indicated that PSGL-1 on Th1 cells functions as an E-selectin ligand, the molecular nature of E-selectin ligands other than PSGL-1 remains unknown. In this study, we show that a 130-kDa glycoprotein was precipitated by an E-selectin-IgG chimera from mouse Th1 cells. This protein was cleaved by O-sialoglycoprotein endopeptidase and required sialic acid for E-selectin binding. The mAb 1B11, which recognizes the 130-kDa glycoform of CD43, recognized the 130-kDa band in the E-selectin-IgG precipitate. In addition, immunoprecipitation of the E-selectin-IgG precipitate with 1B11 depleted the 130-kDa protein, further confirming its identity as CD43. CD43 was also precipitated with E-selectin-IgG from cultured human T cells. E-selectin-dependent cell rolling on CD43 was observed under flow conditions using a CD43-IgG chimera generated in Chinese hamster ovary cells expressing α-1,3-fucosyltransferase VII and a core 2 β-1,6-N-acetylglucosaminyltransferase. These results suggest that CD43, when modified by a specific set of glycosyltranferases, can function as an E-selectin ligand and therefore potentially mediate activated T cell migration into inflamed sites.
Activated T cells migrate from the blood into nonlymphoid tissues through a multistep process that involves cell rolling, arrest, and transmigration. P-Selectin glycoprotein ligand-1 (PSGL-1) is a major ligand for P-selectin expressed on subsets of activated T cells such as Th1 cells and mediates cell rolling on vascular endothelium. Rolling cells are arrested through a firm adhesion step mediated by integrins. Although chemokines presented on the endothelium trigger integrin activation, a second mechanism has been proposed where signaling via rolling receptors directly activates integrins. In this study, we show that Ab-mediated cross-linking of the PSGL-1 on Th1 cells enhances LFA-1-dependent cell binding to ICAM-1. PSGL-1 cross-linking did not enhance soluble ICAM-1 binding but induced clustering of LFA-1 on the cell surface, suggesting that an increase in LFA-1 avidity may account for the enhanced binding to ICAM-1. Combined stimulation by PSGL-1 cross-linking and the Th1-stimulating chemokine CXCL10 or CCL5 showed a more than additive effect on LFA-1-mediated Th1 cell adhesion as well as on LFA-1 redistribution on the cell surface. Moreover, PSGL-1-mediated rolling on P-selectin enhanced the Th1 cell accumulation on ICAM-1 under flow conditions. PSGL-1 cross-linking induced activation of protein kinase C isoforms, and the increased Th1 cell adhesion observed under flow and also static conditions was strongly inhibited by calphostin C, implicating protein kinase C in the intracellular signaling in PSGL-1-mediated LFA-1 activation. These results support the idea that PSGL-1-mediated rolling interactions induce intracellular signals leading to integrin activation, facilitating Th1 cell arrest and subsequent migration into target tissues.
Leukocyte infiltration during inflammation is mediated by the sequential actions of adhesion molecules and chemokines. By using a rat ureteral obstruction model, we showed previously that L-selectin plays an important role in leukocyte infiltration into the kidney. Here we report the purification, identification, and characterization of an L-selectin-binding heparan sulfate proteoglycan (HSPG) expressed in the rat kidney. Partial amino acid sequencing and Western blotting analyses showed that the L-selectin-binding HSPG is collagen XVIII, a basement membrane HSPG. The binding of L-selectin to isolated collagen XVIII was specifically inhibited by an anti-L-selectin monoclonal antibody, EDTA, treatment of the collagen XVIII with heparitinase or heparin but not by chemically desulfated heparin. A cell binding assay showed that the Lselectin-collagen XVIII interaction mediates cell adhesion. Interestingly, collagen XVIII also interacted with a chemokine, monocyte chemoattractant protein-1, and presented it to a monocytic cell line, THP-1, which enhanced the ␣ 4  1 integrin-mediated binding of the THP-1 cells to vascular cell adhesion molecule-1. Thus, collagen XVIII may provide a link between selectin-mediated cell adhesion and chemokine-induced cellular activation and accelerate the progression of leukocyte infiltration in renal inflammation.L-selectin was initially identified as a lymphocyte homing receptor that plays a crucial role in lymphocyte migration into peripheral lymph nodes (1). Subsequently, this molecule was found to be expressed on other types of leukocytes, such as neutrophils and monocytes, and to be involved in leukocyte migration into inflamed tissues (2-4). In agreement with these reports, L-selectin-deficient mice show severely impaired lymphocyte homing and leukocyte infiltration to sites of inflammation (5, 6).L-selectin-binding molecules are found not only in the high endothelial venules of peripheral lymph nodes but also in nonvascular tissues, such as the white matter and choroid plexus of the central nervous system and the renal tubules (7). We have shown previously that leukocyte infiltration into the kidney interstitium induced by ureteral obstruction was significantly reduced by the administration of an anti-rat L-selectin blocking mAb 1 or a sulfated glycolipid, sulfatide, which binds to L-selectin in vitro (8, 9). These observations prompted us to examine L-selectin-reactive molecules that are expressed in the kidney. We first identified sulfatide, a sulfated glycolipid expressed in the renal distal tubules, as an L-selectin-binding molecule in the kidney (9). Subsequent analyses revealed that, in addition to sulfatide, L-selectin-binding chondroitin sulfate proteoglycans and heparan sulfate proteoglycans (HSPGs) are both expressed in the kidney (10). Versican was identified as one of the L-selectin-binding chondroitin sulfate proteoglycans (11,12), whereas L-selectin-binding HSPGs with core protein sizes of 160 and 180 kDa (13) have remained undefined.In the present study, we isolat...
Background Biomarkers that can accurately predict the efficacy of immune checkpoint inhibitors (ICIs) against programmed death 1 (PD-1) ligand in cancer immunotherapy are urgently needed. We have previously reported a novel formula that predicts the response to treatment with second-line nivolumab with high sensitivity and specificity in patients with non-small cell lung cancer (NSCLC) previously treated with chemotherapy. The formula was based on the percentages of CD62LlowCD4+ T cells (effector T cells; %Teff) and CD4+CD25+FOXP3+ T cells (regulatory T cells; %Treg) in the peripheral blood before treatment estimated using the peripheral blood mononuclear cell (PBMC) method. Here, we investigated the applicability of the formula (K-index) to predict the response to treatment with another ICI to expand its clinical applicability. Furthermore, we developed a simpler assay method based on whole blood (WB) samples to overcome the limitations of the PBMC method, such as technical difficulties, in obtaining the K-index. Methods The K-index was evaluated using the PBMC method in 59 patients with NSCLC who received first-line pembrolizumab treatment. We also assessed the K-index using the WB method and estimated the correlation between the measurements obtained using both methods in 76 patients with lung cancer. Results This formula consistently predicted the response to first-line pembrolizumab therapy in patients with NSCLC. The WB method correlated well with the PBMC method to obtain %Teff, %Treg, and the formula value. The WB method showed high repeatability (coefficient of variation, < 10%). The data obtained using WB samples collected in tubes containing either heparin or EDTA-2K and stored at room temperature (18–24 °C) for one day after blood sampling did not differ. Additionally, the performance of the WB method was consistent in different flow cytometry instruments. Conclusions The K-index successfully predicted the response to first-line therapy with pembrolizumab, as reported earlier for the second-line therapy with nivolumab in patients with NSCLC. The WB method established in this study can replace the cumbersome PBMC method in obtaining the K-index. Overall, this study suggests that the K-index can predict the response to anti-PD-1 therapy in various cancers, including NSCLC.
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