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Kazoe Y, Mawatari K, Li L, Emon H, Miyawaki N, Chinen H, Morikawa K, Yoshizaki A, Dittrich PS, Kitamori T. Lipid Bilayer-Modified Nanofluidic Channels of Sizes with Hundreds of Nanometers for Characterization of Confined Water and Molecular/Ion Transport. J Phys Chem Lett 2020; 11:5756-5762. [PMID: 32633535 DOI: 10.1021/acs.jpclett.0c01084] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Water inside and between cells with dimensions on the order of 101-103 nm such as synaptic clefts and mitochondria is thought to be important to biological functions, such as signal transmissions and energy production. However, the characterization of water in such spaces has been difficult owing to the small size and complexity of cellular environments. To this end, we proposed and fabricated a biomimetic nanospace exploiting nanofluidic channels with defined dimensions of hundreds of nanometers and controlled environments. A method of modifying a glass nanochannel with a unilamellar lipid bilayer was developed. We revealed that 2.1-5.6 times higher viscosity of water arises in a 200 nm sized biomimetic nanospace by interactions between water molecules and the lipid bilayer surface and significantly affects the molecular/ion transport that is required for the biological functions. The proposed method provides both a technical breakthrough and new findings to the fields of physical chemistry and biology.
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Affiliation(s)
- Yutaka Kazoe
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Kazuma Mawatari
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
- Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Lixiao Li
- Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Hisaki Emon
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Naoya Miyawaki
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Hiroyuki Chinen
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Kyojiro Morikawa
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Ayumi Yoshizaki
- Department of Dermatology, School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Petra S Dittrich
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Takehiko Kitamori
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
- Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
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Riese SB, Buscher K, Enders S, Kuehne C, Tauber R, Dernedde J. Structural requirements of mono- and multivalent L-selectin blocking aptamers for enhanced receptor inhibition in vitro and in vivo. Nanomedicine 2016; 12:901-908. [PMID: 26772426 DOI: 10.1016/j.nano.2015.12.379] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/28/2015] [Accepted: 12/24/2015] [Indexed: 01/08/2023]
Abstract
UNLABELLED L-selectin mediates extravasation of leukocytes from blood into the surrounding tissue during inflammation and is therefore a therapeutical target in certain overwhelming immune reactions. In this study, we characterized an L-selectin specific blocking DNA aptamer with respect to nucleotide composition and target binding. Introduction of deletions and nucleotide exchanges resulted in an optimized DNA sequence but preservation of the IC50 in the low nanomolar range. The inhibitory potential was significantly increased when the aptamer was displayed as a di- and trimer connected via appropriate linker length. Similar to monoclonal antibodies, trimer yielded picomolar IC50 values in a competitive binding assay. In comparison to the monovalent aptamer, the trivalent assembly reduced PBMC interactions to L-selectin ligands 90-fold under shear and exerted superior inhibition of PBMC rolling in vivo. In conclusion, our work demonstrates the feasibility of optimizing aptamer sequences and shows that multivalent ligand presentation enables superior adhesion receptor targeting. FROM THE CLINICAL EDITOR During inflammation, leukocytes extravasate from blood vessels under chemotaxic signals. The presence of L-selectin on endothelium acts as a mediator for the extravasation process. In this study, the authors investigated an L-selectin specific blocking DNA aptamer in various forms, as inhibitors to leukocyte binding and extravasation. This new approach confirmed the potential use of aptamers in clinical setting.
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Affiliation(s)
- Sebastian B Riese
- Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-Universitätsmedizin Berlin, Berlin, Germany.
| | - Konrad Buscher
- Institute for Physiological Chemistry Pathobiochemistry, University of Muenster, Muenster, Germany; Department of Nephrology and Rheumatology, University Hospital Muenster, Muenster, Germany.
| | - Sven Enders
- Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-Universitätsmedizin Berlin, Berlin, Germany.
| | - Christian Kuehne
- Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-Universitätsmedizin Berlin, Berlin, Germany.
| | - Rudolf Tauber
- Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-Universitätsmedizin Berlin, Berlin, Germany.
| | - Jens Dernedde
- Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-Universitätsmedizin Berlin, Berlin, Germany.
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Panagos CG, Thomson DS, Moss C, Hughes AD, Kelly MS, Liu Y, Chai W, Venkatasamy R, Spina D, Page CP, Hogwood J, Woods RJ, Mulloy B, Bavington CD, Uhrín D. Fucosylated chondroitin sulfates from the body wall of the sea cucumber Holothuria forskali: conformation, selectin binding, and biological activity. J Biol Chem 2014; 289:28284-98. [PMID: 25147180 PMCID: PMC4192483 DOI: 10.1074/jbc.m114.572297] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 08/09/2014] [Indexed: 11/06/2022] Open
Abstract
Fucosylated chondroitin sulfate (fCS) extracted from the sea cucumber Holothuria forskali is composed of the following repeating trisaccharide unit: → 3)GalNAcβ4,6S(1 → 4) [FucαX(1 → 3)]GlcAβ(1 →, where X stands for different sulfation patterns of fucose (X = 3,4S (46%), 2,4S (39%), and 4S (15%)). As revealed by NMR and molecular dynamics simulations, the fCS repeating unit adopts a conformation similar to that of the Le(x) blood group determinant, bringing several sulfate groups into close proximity and creating large negative patches distributed along the helical skeleton of the CS backbone. This may explain the high affinity of fCS oligosaccharides for L- and P-selectins as determined by microarray binding of fCS oligosaccharides prepared by Cu(2+)-catalyzed Fenton-type and photochemical depolymerization. No binding to E-selectin was observed. fCS poly- and oligosaccharides display low cytotoxicity in vitro, inhibit human neutrophil elastase activity, and inhibit the migration of neutrophils through an endothelial cell layer in vitro. Although the polysaccharide showed some anti-coagulant activity, small oligosaccharide fCS fragments had much reduced anticoagulant properties, with activity mainly via heparin cofactor II. The fCS polysaccharides showed prekallikrein activation comparable with dextran sulfate, whereas the fCS oligosaccharides caused almost no effect. The H. forskali fCS oligosaccharides were also tested in a mouse peritoneal inflammation model, where they caused a reduction in neutrophil infiltration. Overall, the data presented support the action of fCS as an inhibitor of selectin interactions, which play vital roles in inflammation and metastasis progression. Future studies of fCS-selectin interaction using fCS fragments or their mimetics may open new avenues for therapeutic intervention.
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Affiliation(s)
- Charalampos G Panagos
- From the EaStCHEM School of Chemistry, Joseph Black Building, The King's Buildings, University of Edinburgh, Edinburgh EH9 3JJ, United Kingdom
| | - Derek S Thomson
- GlycoMar Ltd., European Centre for Marine Biotechnology, Dunstaffnage Marine Laboratory, Oban, Argyll PA37 1QA, United Kingdom
| | - Claire Moss
- GlycoMar Ltd., European Centre for Marine Biotechnology, Dunstaffnage Marine Laboratory, Oban, Argyll PA37 1QA, United Kingdom
| | - Adam D Hughes
- the Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll PA37 1QA, United Kingdom
| | - Maeve S Kelly
- the Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll PA37 1QA, United Kingdom
| | - Yan Liu
- the Glycosciences Laboratory, Hammersmith Campus, Imperial College London, London W12 0NN, United Kingdom
| | - Wengang Chai
- the Glycosciences Laboratory, Hammersmith Campus, Imperial College London, London W12 0NN, United Kingdom
| | - Radhakrishnan Venkatasamy
- the Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London SE1 9NH, United Kingdom
| | - Domenico Spina
- the Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London SE1 9NH, United Kingdom
| | - Clive P Page
- the Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London SE1 9NH, United Kingdom
| | - John Hogwood
- the National Institute of Biological Standards and Controls, South Mimms, Potters Bar, Hertfordshire EN6 3QG, United Kingdom
| | - Robert J Woods
- the Complex Carbohydrate Research Center, the University of Georgia, Athens, Georgia 30602, and the School of Chemistry, National University of Ireland Galway, University Road, Galway, Ireland
| | - Barbara Mulloy
- the Glycosciences Laboratory, Hammersmith Campus, Imperial College London, London W12 0NN, United Kingdom, the Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London SE1 9NH, United Kingdom
| | - Charlie D Bavington
- GlycoMar Ltd., European Centre for Marine Biotechnology, Dunstaffnage Marine Laboratory, Oban, Argyll PA37 1QA, United Kingdom
| | - Dušan Uhrín
- From the EaStCHEM School of Chemistry, Joseph Black Building, The King's Buildings, University of Edinburgh, Edinburgh EH9 3JJ, United Kingdom,
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Gupta VK. Rupture of multiple catch-slip bonds: Two-state two-pathway catch-slip bonds. Eur Phys J E Soft Matter 2013; 36:133. [PMID: 24272665 DOI: 10.1140/epje/i2013-13133-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 10/29/2013] [Indexed: 06/02/2023]
Abstract
We performed Monte Carlo simulation of the detachment of a polymorphonuclear (PMN) leukocyte immersed in a Newtonian fluid and adhered to a substrate by multiple catch-slip bonds. We found that at certain loading rates the interplay of multiple catch-slip bonds leads to a bimodal distribution of the bond rupture force. We also found that the low force peak in these bond rupture force distributions switches to a high force peak with a gradual increase in the loading rate. These trends in the bond rupture force distributions are characteristics of two-state systems. Consequently, though individual catch-slip bonds follow one-state two-pathway energy landscape, their interplay mimics a two-state two-pathway energy landscape.
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Affiliation(s)
- V K Gupta
- University of Maryland Baltimore County, 21250, Baltimore, Maryland, USA,
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Cao TM, Mitchell MJ, Liesveld J, King MR. Stem cell enrichment with selectin receptors: mimicking the pH environment of trauma. Sensors (Basel) 2013; 13:12516-26. [PMID: 24048341 PMCID: PMC3821329 DOI: 10.3390/s130912516] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/06/2013] [Accepted: 09/11/2013] [Indexed: 11/16/2022]
Abstract
The isolation of hematopoietic stem and progenitor cells (HSPCs) is critical for transplantation therapy and HSPC research, however current isolation techniques can be prohibitively expensive, time-consuming, and produce variable results. Selectin-coated microtubes have shown promise in rapidly isolating HSPCs from human bone marrow, but further purification of HSPCs remains a challenge. Herein, a biomimetic device for HSPC isolation is presented to mimic the acidic vascular microenvironment during trauma, which can enhance the binding frequency between L-selectin and its counter-receptor PSGL-1 and HSPCs. Under acidic pH conditions, L-selectin coated microtubes enhanced CD34+ HSPC adhesion, as evidenced by decreased cell rolling velocity and increased rolling flux. Dynamic light scattering was utilized as a novel sensor to confirm an L-selectin conformational change under acidic conditions, as previously predicted by molecular dynamics. These results suggest that mimicking the acidic conditions of trauma can induce a conformational extension of L-selectin, which can be utilized for flow-based, clinical isolation of HSPCs.
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Affiliation(s)
- Thong M. Cao
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 14850, USA; E-Mails: (T.M.C.); (M.J.M.)
| | - Michael J. Mitchell
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 14850, USA; E-Mails: (T.M.C.); (M.J.M.)
| | - Jane Liesveld
- School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA; E-Mail:
| | - Michael R. King
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 14850, USA; E-Mails: (T.M.C.); (M.J.M.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-607-255-9803; Fax: +1-607-255-7330
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Deng W, Cho S, Li R. FERM domain of moesin desorbs the basic-rich cytoplasmic domain of l-selectin from the anionic membrane surface. J Mol Biol 2013; 425:3549-62. [PMID: 23796515 DOI: 10.1016/j.jmb.2013.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 06/13/2013] [Accepted: 06/14/2013] [Indexed: 01/08/2023]
Abstract
Moesin and calmodulin (CaM) jointly associate with the cytoplasmic domain of l-selectin in the cell to modulate the function and ectodomain shedding of l-selectin. Using fluorescence spectroscopy, we have examined the association of moesin FERM domain with the recombinant transmembrane and cytoplasmic domains of l-selectin (CLS) reconstituted in model phospholipid liposomes. The dissociation constant of moesin FERM domain to CLS in the phosphatidylcholine liposome is about 300nM. In contrast to disrupting the CaM association with CLS, inclusion of anionic phosphatidylserine lipids in the phosphatidylcholine liposome increased the apparent binding affinity of moesin FERM domain for CLS. Using the environmentally sensitive fluorescent probe attached to the cytoplasmic domain of CLS and the nitroxide quencher attached to the lipid bilayer, we showed that the association of moesin FERM domain induced the desorption of the basic-rich cytoplasmic domain of CLS from the anionic membrane surface, which enabled subsequent association of CaM to the cytoplasmic domain of CLS. These results have elucidated the molecular basis for the moesin/l-selectin/CaM ternary complex and suggested an important role of phospholipids in modulating l-selectin function and shedding.
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Affiliation(s)
- Wei Deng
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, 2015 Uppergate Drive NE, Room 440, Atlanta, GA 30322, USA
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Abstract
Calmodulin, an intracellular calcium-binding protein, is thought to regulate ectodomain shedding of many membrane proteins, but the underlying molecular mechanism has remained unclear. Basing on a solution structure of calcium-loaded calmodulin in complex with a L-selectin fragment that contains a portion of its transmembrane domain, Gifford et al. (University of Calgary) recently suggested that calmodulin regulates L-selectin shedding by binding directly to a portion of the L-selectin transmembrane domain in a compact conformation. Using fluorescently labeled calmodulin, we show however that calmodulin adopts a distinctly different and much more extended conformation when it binds to the CLS peptide (i.e. the entire transmembrane and cytoplasmic domains of L-selectin) reconstituted in the phosphatidylcholine liposome with micromolar dissociation constant and in a calcium-independent manner. Calmodulin adopts a similarly extended conformation in a ternary complex with the N-terminal FERM domain of moesin and CLS reconstituted in the phospholipid liposome that mimics the native membrane environment. These results indicate that calmodulin does not bind directly to the transmembrane domain of L-selectin. Understanding the association of calmodulin with L-selectin helps to shed light on the mechanisms underlying regulation of ectodomain shedding.
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Affiliation(s)
- Wei Deng
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - John A. Putkey
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, United States of America
- * E-mail:
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Gupta VK. Rupture of single receptor-ligand bonds: a new insight into probability distribution function. Colloids Surf B Biointerfaces 2013; 101:501-9. [PMID: 23010061 DOI: 10.1016/j.colsurfb.2012.07.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 07/11/2012] [Accepted: 07/16/2012] [Indexed: 11/18/2022]
Abstract
Single molecule force spectroscopy is widely used to determine kinetic parameters of dissociation by analyzing bond rupture data obtained via applying mechanical force to cells, capsules, and beads that are attached to an intermolecular bond. The current analysis assumes that the intermolecular bond force is equal to the externally applied mechanical force. We confirm that viscous drag alone or in combination with cellular deformation resulting in viscoelasticity modulates bond force so that the instantaneous intermolecular bond force is not equivalent to the applied force. The bond force modulation leads to bond rupture time and force histograms that differ from those predicted by probability distribution function (PDF) using the current approach. A new methodology that accounts for bond force modulation in obtaining PDF is presented. The predicted histograms from the new methodology are in excellent agreement with the respective histograms obtained from Monte Carlo simulation.
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Affiliation(s)
- V K Gupta
- University of Maryland Baltimore County, Baltimore, MD 21250, USA.
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Abstract
BACKGROUND L-selectin ligands are induced on the endothelium of inflammatory sites. L-selectin expression on neutrophils and monocytes may mediate the primary adhesion of these cells at sites of inflammation by mediating the leukocyte-leukocyte interactions that facilitate their recruitment. L-selectin retains functional activity in its soluble form. Levels of soluble L-selectin have been reported as both elevated and lowered in patients with systemic sclerosis (SSc). This preliminary study seeks to discern amongst these disparate results and to discover whether there is an association between L-selectin concentrations in plasma and skin damage in SSc patients. METHODOLOGY AND PRINCIPAL FINDINGS Nineteen cases with limited systemic sclerosis (lSSc) and 11 cases with diffuse systemic sclerosis (dSSc) were compared on a pairwise basis to age- and sex-matched controls. Criteria of the American College of Rheumatology were used to diagnose SSc. Skin involvement was assessed using the modified Rodnan skin score (mRSS). We find no association between mRSS and plasma L-selectin concentration in lSSc cases (p = 0.9944) but a statistically significant negative correlation in dSSc cases (R(2) = 73.11 per cent, p = 0.0008). The interpretation of the slope for dSSc cases is that for each increase of 100 ng/ml in soluble L-selectin concentration, the mRSS drops 4.22 (95 per cent CI: 2.29, 6.16). There was also a highly statistically significant negative correlation between sL-selectin and disease activity (p = 0.0007) and severity (p = 0.0007) in dSSc cases but not in lSSc cases (p = 0.2596, p = 0.7575, respectively). CONCLUSIONS AND SIGNIFICANCE No effective treatments exist for skin damage in SSc patients. Nor is there a laboratory alternative to the modified Rodnan skin score as is the case for other organs within the body. Modulation of circulating L-selectin is a promising target for reducing skin damage in dSSc patients. Plasma levels of soluble L-selectin could serve as an outcome measure for dSSc patients in clinical trials.
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Affiliation(s)
- James V Dunne
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
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Mitoma J. [Oligosaccharides in lymphocyte homing]. Tanpakushitsu Kakusan Koso 2008; 53:1598-1603. [PMID: 21089373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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Dotsenko O, Chaturvedi N, Thom SAM, Wright AR, Mayet J, Shore A, Schalkwijk C, Hughes AD. Platelet and leukocyte activation, atherosclerosis and inflammation in European and South Asian men. J Thromb Haemost 2007; 5:2036-42. [PMID: 17883700 PMCID: PMC2650817 DOI: 10.1111/j.1538-7836.2007.02711.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Increased platelet activation occurs in ischemic heart disease (IHD), but increased platelet activation is also seen in cerebrovascular atherosclerosis and peripheral artery disease. It is not clear therefore whether platelet activation is an indicator of IHD or a marker of generalized atherosclerosis and inflammation. South Asian subjects are at high risk of IHD, but little is known regarding differences in platelet and leukocyte function between European and South Asian subjects. METHODS Fifty-four male subjects (age 49-79 years) had coronary artery calcification measured by multislice computed tomography (CT), aortic atherosclerosis assessed by measurement of carotid-femoral pulse wave velocity (aortic PWV), and femoral and carotid atherosclerosis measured by B-mode ultrasound. Platelet and leukocyte activation was assessed by flow cytometry of platelet-monocyte complexes (PMC), platelet expression of PAC-1 binding site and CD62P, and expression of L-selectin on leukocytes. RESULTS Elevated circulating PMC correlated significantly with elevated aortic PWV and PMC were higher in subjects with femoral plaques. In contrast PMC did not differ by increasing coronary artery calcification category or presence of carotid plaques. Higher numbers of PMC were independently related to elevated levels of C-reactive protein (CRP), higher aortic PWV, hypertension and smoking in a multivariate model. Markers of platelet and leukocyte activation did not differ significantly by ethnicity. CONCLUSIONS Increased PMC are related to the extent of aortic and femoral atherosclerosis rather than coronary or carotid atherosclerosis. The association between elevated CRP and increased PMC suggests that inflammation in relation to generalized atherosclerosis may play an important role in PMC activation.
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Affiliation(s)
- O Dotsenko
- International Centre for Circulatory Health, NHLI Division, Faculty of Medicine, St Mary's Hospital and Imperial College London, London, UK
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Abstract
L-selectin-mediated leukocyte rolling has been proposed to require a high rate of bond formation compared to that of P-selectin to compensate for its much higher off-rate. To test this hypothesis, a microbead system was utilized to measure relative L-selectin and P-selectin bond formation rates on their common ligand P-selectin glycoprotein ligand-1 (PSGL-1) under shear flow. Using video microscopy, we tracked selectin-coated microbeads to detect the formation frequency of adhesive tether bonds. From velocity distributions of noninteracting and interacting microbeads, we observed that tether bond formation rates for P-selectin on PSGL-1 decreased with increasing wall shear stress, from 0.14 +/- 0.04 bonds/microm at 0.2 dyn/cm(2) to 0.014 +/- 0.003 bonds/microm at 1.0 dyn/cm(2). In contrast, L-selectin tether bond formation increased from 0.017 +/- 0.005 bonds/microm at 0.2 dyn/cm(2) to 0.031 +/- 0.005 bonds/microm at 1.0 dyn/cm(2). L-selectin tether bond formation rates appeared to be enhanced by convective transport, whereas P-selectin rates were inhibited. The transition force for the L-selectin catch-slip transition of 44 pN/bond agreed well with theoretical models (Pereverzev et al. 2005. Biophys. J. 89:1446-1454). Despite catch bond behavior, hydrodymanic shear thresholding was not detected with L-selectin beads rolling on PSGL-1. We speculate that shear flow generated compressive forces may enhance L-selectin bond formation relative to that of P-selectin and that L-selectin bonds with PSGL-1 may be tuned for the compressive forces characteristic of leukocyte-leukocyte collisions during secondary capture on the blood vessel wall. This is the first report, to our knowledge, comparing L-selectin and P-selectin bond formation frequencies in shear flow.
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Affiliation(s)
| | - William H. Guilford
- Address reprint requests to William H. Guilford, Dept. of Biomedical Engineering, PO Box 800759, MR5, 1111 415 Lane Road, University of Virginia, Charlottesville, VA 22908. Tel.: 434-924-9908; Fax: 434-982-3870.
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Ahmad I, Hoessli DC, Gupta R, Walker-Nasir E, Rafik SM, Choudhary MI, Shakoori AR. In silico determination of intracellular glycosylation and phosphorylation sites in human selectins: implications for biological function. J Cell Biochem 2007; 100:1558-72. [PMID: 17230456 DOI: 10.1002/jcb.21156] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Post-translational modifications provide the proteins with the possibility to perform functions in addition to those determined by their primary sequence. However, analysis of multifunctional protein structures in the environment of cells and body fluids is made especially difficult by the presence of other interacting proteins. Bioinformatics tools are therefore helpful to predict protein multifunctionality through the identification of serine and threonine residues wherein the hydroxyl group is likely to become modified by phosphorylation or glycosylation. Moreover, serines and threonines where both modifications are likely to occur can also be predicted (YinYang sites), to suggest further functional versatility. Structural modifications of hydroxyl groups of P-, E-, and L-selectins have been predicted and possible functions resulting from such modifications are proposed. Functional changes of the three selectins are based on the assumption that transitory and reversible protein modifications by phosphate and O-GlcNAc cause specific conformational changes and generate binding sites for other proteins. The computer-assisted prediction of glycosylation and phosphorylation sites in selectins should be helpful to assess the contribution of dynamic protein modifications in selectin-mediated inflammatory responses and cell-cell adhesion processes that are difficult to determine experimentally.
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Affiliation(s)
- Ishtiaq Ahmad
- Institute of Molecular Sciences and Bioinformatics, Lahore, Pakistan
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Abstract
Selectins are adhesion receptors that participate in inflammation and tumor cell metastasis. The anti-inflammatory and antimetastatic activities of heparins have been related partly to their ability to interact with P- and L-selectin. The recent findings that various heparins differ in antimetastatic activity were explained by differences in their P- and L-selectin binding ability. To obtain data to illustrate the binding characteristics, we detected for the first time the binding kinetics and affinity of the two low molecular weight heparins (LMWHs) enoxaparin and nadroparin, and of the unfractionated heparin Liquemin N to P- and L-selectin using a quartz crystal microbalance biosensor. Enoxaparin and nadroparin behave nearly identical in their binding affinity to both P-selectin ( KD 4.60 x 10 (- 6) M versus 7.61 x 10 (- 6) M) and L-selectin ( KD 2.01 x 10 (- 6) M versus 2.84 x 10 (- 6) M). Liquemin N displayed slightly higher affinities to both selectins ( KD 6.07 x 10 (- 7) M versus 1.07 x 10 (- 7) M). The differences are caused by a higher association rate compared with that of the LMWHs. These data support recent findings of antimetastatic activities, but illustrate that the intrinsic selectin binding does not entirely reflect the antimetastatic activities in vivo.
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Affiliation(s)
- Dirk Simonis
- Department of Pharmacy, Rheinische Friedrich Wilhelms University Bonn, Av. der Immenburg 4, 531L1 Bonn, Germany
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Abstract
Flow-enhanced cell adhesion is a counterintuitive phenomenon that has been observed in several biological systems. Flow augments L-selectin-dependent adhesion by increasing the initial tethering of leukocytes to vascular surfaces and by strengthening their subsequent rolling interactions. Tethering or rolling might be influenced by physical factors that affect the formation or dissociation of selectin-ligand bonds. We recently demonstrated that flow enhanced rolling of L-selectin-bearing microspheres or neutrophils on P-selectin glycoprotein ligand-1 by force decreased bond dissociation. Here, we show that flow augmented tethering of these microspheres or cells to P-selectin glycoprotein ligand-1 by three transport mechanisms that increased bond formation: sliding of the sphere bottom on the surface, Brownian motion, and molecular diffusion. These results elucidate the mechanisms for flow-enhanced tethering through L-selectin.
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Affiliation(s)
- Tadayuki Yago
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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17
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Abstract
Tensile mechanical force was long assumed to increase the detachment rates of biological adhesive bonds (Bell, 1978). However, in the last few years, several receptor–ligand pairs were shown to form “catch bonds,” whose lifetimes are enhanced by moderate amounts of force. These include the bacterial adhesive protein FimH binding to its ligand mannose (Thomas et al., 2002; Thomas et al., 2006), blood cell adhesion proteins P- and L-selectin binding to sialyl Lewis X (sLeX)–containing ligands (Marshall et al., 2003; Evans et al., 2004; Sarangapani et al., 2004), and the myosin–actin motor protein interaction (Guo and Guilford, 2006). The structural mechanism behind this counterintuitive force–enhanced catch bond behavior is of great interest.
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Affiliation(s)
- Wendy Thomas
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.
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18
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Phan UT, Waldron TT, Springer TA. Remodeling of the lectin-EGF-like domain interface in P- and L-selectin increases adhesiveness and shear resistance under hydrodynamic force. Nat Immunol 2006; 7:883-9. [PMID: 16845394 PMCID: PMC1764822 DOI: 10.1038/ni1366] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Accepted: 06/22/2006] [Indexed: 02/06/2023]
Abstract
Crystal structures of the lectin and epidermal growth factor (EGF)-like domains of P-selectin show 'bent' and 'extended' conformations. An extended conformation would be 'favored' by forces exerted on a selectin bound at one end to a ligand and at the other end to a cell experiencing hydrodynamic drag forces. To determine whether the extended conformation has higher affinity for ligand, we introduced an N-glycosylation site to 'wedge open' the interface between the lectin and EGF-like domains of P-selectin. This alteration increased the affinity of P-selectin for its ligand P-selectin glycoprotein 1 (PSGL-1) and thereby the strength of P-selectin-mediated rolling adhesion. Similarly, an asparagine-to-glycine substitution in the lectin-EGF-like domain interface of L-selectin enhanced rolling adhesion under shear flow. Our results demonstrate that force, by 'favoring' an extended selectin conformation, can strengthen selectin-ligand bonds.
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Affiliation(s)
- Uyen T Phan
- CBR Institute for Biomedical Research, Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
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19
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Abstract
L-selectin is a cell adhesion molecule mediating the initial capture and subsequent rolling of leukocytes along the endothelial cells expressing L-selectin ligands. In addition to its action in adhesion, an intracellular signaling role for L-selectin has been recognized. Its cytoplasmic domain is involved in signal transduction following antibody crosslinking and in the regulation of receptor binding activity in response to intracellular signals. In this work, we demonstrated that L-selectin crosslinking led to F-actin polymerization and redistribution in human neutrophils. Using immuno-fluorescence microscopy, we observed that F-actin redistribution spatiotemporally related to the polarization of L-selectin. STI571, a specific inhibitor for cytoplasmic tyrosine kinase c-Abl, can inhibit F-actin polymerization and c-Abl redistribution in the activated neutrophils. Furthermore, we determined that c-Abl redistributed to the region where L-selectin polarized and associated with L-selectin in the activated neutrophils. The association between L-selectin and c-Abl was reduced by cytochalasin B. These results suggested that c-Abl was involved in the F-actin alteration triggered by L-selectin crosslinking in human neutrophils.
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Affiliation(s)
- Cuixia Chen
- Institute of Genetics and Cytology, Northeast Normal University, Changchun 130024, P.R. China
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20
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Stibenz D, Gräfe M, Debus N, Hasbach M, Bahr I, Graf K, Fleck E, Thanabalasingam U, Bührer C. Binding of human serum amyloid P componentto L-selectin. Eur J Immunol 2006; 36:446-56. [PMID: 16421944 DOI: 10.1002/eji.200425360] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Serum concentrations of soluble L-selectin by far exceed those of other soluble adhesion molecules, and serum soluble L-selectin concentrations are remarkably stable upon prolonged storage. We present evidence for Ca(2+)-dependent binding interactions between human serum amyloid P (SAP), a proteolysis-resistant pentraxin glycoprotein, and L-selectin, as shown by surface plasmon resonance measurements, protein band shift assays in a native PAGE system, and after SDS-PAGE and membrane transfer. Monoclonal antibodies to L-selectin strongly reduced binding of biotinylated SAP to L-selectin-IgG chimeras immobilized on microtiter plates. As binding was reduced by prior glycopeptidase F treatment of L-selectin but not of SAP, it appears to be based on SAP lectin domain interactions with N-linked L-selectin carbohydrates. In freshly prepared human lymphocytes, SAP incubation induced expression of a beta2 integrin neoepitope associated with high-affinity binding. This was partially blocked by pre-incubation with Fab fragments of two anti-L-selectin antibodies. In flow chamber experiments, SAP inhibited the adherence of human neutrophils to activated endothelium under shear stress. Thus, SAP binds to human L-selectin and affects L-selectin-dependent leukocyte-endothelial interactions.
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Affiliation(s)
- Dietger Stibenz
- Department of Neonatology, Charité Virchow Hospital, Humboldt University, Berlin, Germany
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21
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Rele SM, Cui W, Wang L, Hou S, Barr-Zarse G, Tatton D, Gnanou Y, Esko JD, Chaikof EL. Dendrimer-like PEO glycopolymers exhibit anti-inflammatory properties. J Am Chem Soc 2005; 127:10132-3. [PMID: 16028900 PMCID: PMC2556565 DOI: 10.1021/ja0511974] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new class of high molecular weight polysulfated PEO dendrimer-like glycopolymer has been synthesized by a combination of arm-first and core-first methodologies followed by trichloroacetimidate glycosidation as a facile bioconjugation strategy. An L-selectin antagonist was identified that exhibits 103-fold greater activity than other multivalent sLex glycopolymers and 20-50 times greater potency than other linear heparinoids. A significant reduction in inflammatory cell recruitment was observed in vivo.
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22
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Wang L, Fuster M, Sriramarao P, Esko JD. Endothelial heparan sulfate deficiency impairs L-selectin- and chemokine-mediated neutrophil trafficking during inflammatory responses. Nat Immunol 2005; 6:902-10. [PMID: 16056228 DOI: 10.1038/ni1233] [Citation(s) in RCA: 365] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Accepted: 06/21/2005] [Indexed: 11/08/2022]
Abstract
Here we have studied the involvement of endothelial heparan sulfate in inflammation by inactivating the enzyme N-acetyl glucosamine N-deacetylase-N-sulfotransferase-1 in endothelial cells and leukocytes, which is required for the addition of sulfate to the heparin sulfate chains. Mutant mice developed normally but showed impaired neutrophil infiltration in various inflammation models. These effects were due to changes in heparan sulfate specifically in endothelial cells. Decreased neutrophil infiltration was partially due to altered rolling velocity correlated with weaker binding of L-selectin to endothelial cells. Chemokine transcytosis across endothelial cells and presentation on the cell surface were also reduced, resulting in decreased neutrophil firm adhesion and migration. Thus, endothelial heparan sulfate has three functions in inflammation: by acting as a ligand for L-selectin during neutrophil rolling; in chemokine transcytosis; and by binding and presenting chemokines at the lumenal surface of the endothelium.
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Affiliation(s)
- Lianchun Wang
- Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California 92093-0687, USA
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23
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Ushakova NA, Preobrazhenskaya ME, Bird MI, Priest R, Semenov AV, Mazurov AV, Nifantiev NE, Pochechueva TV, Galanina OE, Bovin NV. Monomeric and Multimeric Blockers of Selectins: Comparison of in vitro and in vivo Activity. Biochemistry (Moscow) 2005; 70:432-9. [PMID: 15892609 DOI: 10.1007/s10541-005-0133-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The potency of the oligosaccharides SiaLe(x), SiaLe(a), HSO(3)Le(x), and HSO(3)Le(a), their conjugates with polyacrylamide (PAA, 40 kD), and other monomeric and polymeric selectin inhibitors has been compared with that of the polysaccharide fucoidan. The following assay systems were used: 1) a 96-well assay based either on the use of recombinant E-, P-, and L-selectins or an analogous assay with natural P-selectin isolated from human platelets; 2) a platelet-based P-selectin cell assay; and 3) a rat model of peritoneal inflammation. IC(50) values for the neoglycoconjugate SiaLe(a)-PAA were 6, 40, and 85 microM for recombinant E-, P-, and L-selectins, respectively; all monomeric inhibitors were about two orders of magnitude weaker. PAA-conjugates, containing as a ligand tyrosine-O-sulfate (sTyr) in addition to one of the sialylated oligosaccharides, were the most potent synthetic blockers in vitro. Compared with fucoidan, the most potent known P- and L-selectin blocker, the bi-ligand glycoconjugate HSO(3)Le(a)-PAA-sTyr displayed similar inhibitory activity in vitro towards L-selectin and about ten times lower activity towards P-selectin. All of the tested synthetic polymers displayed a similar ability to inhibit neutrophil extravasation in the peritonitis model (in vivo) at 10 mg/kg. The data provide evidence that monomeric SiaLe(x) is considerably more effective as a selectin blocker in vivo than in vitro, whereas the opposite is true for fucoidan and the bi-ligand neoglycoconjugate HSO(3)Le(a)-PAA-sTyr.
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Affiliation(s)
- N A Ushakova
- Orekhovich Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, 119121 Moscow, Russia.
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24
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Yamaguchi M, Ishida H, Kanamori A, Kannagi R, Kiso M. 6-O-Sulfo sialylparagloboside and sialyl Lewis X neo-glycolipids containing lactamized neuraminic acid: Synthesis and antigenic reactivity against G159 monoclonal antibody. Glycoconj J 2005; 22:95-108. [PMID: 16133830 DOI: 10.1007/s10719-005-0352-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2004] [Revised: 01/10/2005] [Accepted: 01/18/2005] [Indexed: 10/25/2022]
Abstract
Synthesis and antigenic reactivity of 6-O-sulfo sialylparagloboside (SPG) and sialyl Lewis X (sLeX) neo-glycolipids containing lactamized neuraminic acid are described. The suitably protected GlcNAc-beta (1-->3)-Gal-beta (1-->4)-GlcOSE derivative was glycosylated with NeuTFAc-alpha (2-->3)-Gal imidate to give NeuTFAc-alpha (2-->3)-Galbeta (1-->4)-GlcNAc-beta (1-->3)-Gal-beta (1-->4)-GlcOSE pentasaccharide. The partial N,O-deacylation in the NeuTFAc-alpha (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-alpha (2-->3)-Gal-beta (1-->4) [Fuc-alpha (1-->3)]-GlcNAc-beta (1-->3)-Gal-beta (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.
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Affiliation(s)
- Masanori Yamaguchi
- Department of Applied Bio-Organic Chemistry, Gifu University, Gifu, 501-1193, Japan
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25
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Mowery P, Yang ZQ, Gordon EJ, Dwir O, Spencer AG, Alon R, Kiessling LL. Synthetic glycoprotein mimics inhibit L-selectin-mediated rolling and promote L-selectin shedding. ACTA ACUST UNITED AC 2005; 11:725-32. [PMID: 15157883 DOI: 10.1016/j.chembiol.2004.03.027] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2003] [Revised: 03/05/2004] [Accepted: 03/11/2004] [Indexed: 12/18/2022]
Abstract
L-selectin is a leukocyte cell-surface protein that facilitates the rolling of leukocytes along the endothelium, a process that leads to leukocyte migration to a site of infection. Preventing L-selectin-mediated rolling minimizes leukocyte adhesion and extravasation; therefore, compounds that inhibit rolling may act as anti-inflammatory agents. To investigate the potential role of multivalent ligands as rolling inhibitors, compounds termed neoglycopolymers were synthesized that possess key structural features of physiological L-selectin ligands. Sulfated neoglycopolymers substituted with sialyl Lewis x derivatives (3',6-disulfo Lewis x or 6-sulfo sialyl Lewis x) or a sulfatide analog (3,6-disulfo galactose) inhibited L-selectin-mediated rolling of lymphoid cells. Functional analysis of the inhibitory ligands indicates that they also induce proteolytic release of L-selectin. Thus, their inhibitory potency may arise from their ability to induce shedding. Our data indicate that screening for compounds that promote L-selectin release can identify ligands that inhibit rolling.
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Affiliation(s)
- Patricia Mowery
- Department of Biochemistry, 433 Babcock Drive, University of Wisconsin-Madison, Madison, WI 53706 USA
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26
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Abstract
Leukocytes are recruited from the bloodstream to sites of inflammation by the selectin family of adhesion receptors. In vivo and in vitro studies reveal distinctive rolling velocities of polymorphonuclear leukocytes over E-, P- and L-selectin substrates. The kinetic and mechanical properties of the selectin-ligand bonds responsible for these differences at the single-molecule level are not well understood. Using single-molecule force spectroscopy, we probe in situ the rupture force, unstressed off-rate and reactive compliance of single selectin receptors to single ligands on whole human polymorphonuclear leukocytes (PMNs) under conditions that preserve the proper orientation and post-translational modifications of the selectin ligands. Single L-selectin bonds to PMNs were more labile than either E- or P-selectin in the presence of an applied force. This outcome, along with a higher unstressed off-rate and a higher reactive compliance, explain the faster L-selectin-mediated rolling. By quantifying binding frequency in the presence of a specific blocking monoclonal antibody or following enzyme treatment, we determined that P-selectin glycoprotein ligand-1 is a high-affinity ligand for E-selectin on PMNs under force. The rupture force spectra and corresponding unstressed off-rate and reactive compliance of selectin-ligand bonds provide mechanistic insights that might help to explain the variable rolling of leukocytes over different selectin substrates.
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Affiliation(s)
- William D Hanley
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA
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27
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Abstract
L-selectin is constitutively expressed on the surface of most leucocytes and is important for tethering and subsequent rolling of leucocytes on endothelial cells, facilitating their migration into secondary lymphoid organs (e.g. naive T cells) and sites of inflammation (e.g. neutrophils). Previous studies have shown that the 17-amino-acid L-selectin cytoplasmic tail is important for its function in cell adhesion and, hence, identifying binding partners will provide insight into how L-selectin is regulated in leucocytes. This review describes currently known binding partners of the L-selectin tail and how their associations affect L-selectin function.
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Affiliation(s)
- A Ivetic
- Ludwig Institute for Cancer Research, Royal Free and University College School of Medicine, 91 Riding House Street, London W1W 7BS, UK.
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28
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Abstract
Flow-enhanced cell adhesion is an unexplained phenomenon that might result from a transport-dependent increase in on-rates or a force-dependent decrease in off-rates of adhesive bonds. L-selectin requires a threshold shear to support leukocyte rolling on P-selectin glycoprotein ligand-1 (PSGL-1) and other vascular ligands. Low forces decrease L-selectin–PSGL-1 off-rates (catch bonds), whereas higher forces increase off-rates (slip bonds). We determined that a force-dependent decrease in off-rates dictated flow-enhanced rolling of L-selectin–bearing microspheres or neutrophils on PSGL-1. Catch bonds enabled increasing force to convert short-lived tethers into longer-lived tethers, which decreased rolling velocities and increased the regularity of rolling steps as shear rose from the threshold to an optimal value. As shear increased above the optimum, transitions to slip bonds shortened tether lifetimes, which increased rolling velocities and decreased rolling regularity. Thus, force-dependent alterations of bond lifetimes govern L-selectin–dependent cell adhesion below and above the shear optimum. These findings establish the first biological function for catch bonds as a mechanism for flow-enhanced cell adhesion.
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Affiliation(s)
- Tadayuki Yago
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
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29
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Abstract
A laser trap was used to compare the load-dependent binding kinetics between truncated P- and L-selectin to their natural ligand, P-selectin glycoprotein ligand-1 (PSGL-1) over the predicted physiological range of loading rates. Human PSGL-1 was covalently coupled to polystyrene beads. Chimeric selectins were adsorbed to nitrocellulose-coated glass beads on a coverslip. A PSGL-1 bead was held in a laser trap and touched to a vertical surface of the glass bead, allowing a bond to form between selectin and ligand. The surface was moved away from the microsphere, applying load at a constant rate until bond rupture. Rupture force for both selectins increased with loading rate, but significant differences in rupture force between P- and L-selectin were observed only above 460 pN/s. These data are best represented as two energy barriers to unbinding, with the transition from the low to high loading rate regime at 260-290 pN/s. The data also allow the first estimate of a two-dimensional specific on-rate for binding of these two selectins to their natural ligand (1.7 microm2/s). These data suggest that P- and L-selectin lectin domains have very similar kinetics under physiological conditions.
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Affiliation(s)
- Linda J Rinko
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, USA
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30
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Ivetic A, Florey O, Deka J, Haskard DO, Ager A, Ridley AJ. Mutagenesis of the Ezrin-Radixin-Moesin Binding Domain of L-selectin Tail Affects Shedding, Microvillar Positioning, and Leukocyte Tethering. J Biol Chem 2004; 279:33263-72. [PMID: 15178693 DOI: 10.1074/jbc.m312212200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
L-selectin is a cell adhesion molecule that mediates the initial capture (tethering) and subsequent rolling of leukocytes along ligands expressed on endothelial cells. We have previously identified ezrin and moesin as novel binding partners of the 17-amino acid L-selectin tail, but the biological role of this interaction is not known. Here we identify two basic amino acid residues within the L-selectin tail that are required for binding to ezrin-radixinmoesin (ERM) proteins: arginine 357 and lysine 362. L-selectin mutants defective for ERM binding show reduced localization to microvilli and decreased phorbol 12-myristate 13-acetate-induced shedding of the L-selectin ectodomain. Cells expressing these L-selectin mutants have reduced tethering to the L-selectin ligand P-selectin glycoprotein ligand-1, but rolling velocity on P-selectin glycoprotein ligand-1 is not affected. These results suggest that ERM proteins are required for microvillar positioning of L-selectin and that this is important both for leukocyte tethering and L-selectin shedding.
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Affiliation(s)
- Aleksandar Ivetic
- Ludwig Institute for Cancer Research, Royal Free and University College School of Medicine, 91 Riding House Street, London W1W 7BS United Kingdom.
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31
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Kilian K, Dernedde J, Mueller EC, Bahr I, Tauber R. The interaction of protein kinase C isozymes alpha, iota, and theta with the cytoplasmic domain of L-selectin is modulated by phosphorylation of the receptor. J Biol Chem 2004; 279:34472-80. [PMID: 15192100 DOI: 10.1074/jbc.m405916200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The leukocyte adhesion molecule L-selectin has an important role in the initial steps of leukocyte extravasation during inflammation and lymphocyte homing. Its cytoplasmic domain is involved in signal transduction after L-selectin cross-linking and in the regulation of receptor binding activity in response to intracellular signals. However, the signaling events occurring at the level of the receptor are largely unknown. This study therefore addressed the question of whether protein kinases associate with the cytoplasmic domain of the receptor and mediate its phosphorylation. Using a glutathione S-transferase fusion protein of the L-selectin cytoplasmic domain, we isolated a kinase activity from cellular extracts of the human leukemic Jurkat T-cell line that phosphorylated L-selectin on serine residues. This kinase showed characteristics of the protein kinase C (PKC) family. Moreover, the Ca(2+)-independent PKC isozymes theta and iota were found associated with the cytoplasmic domain of L-selectin. Pseudosubstrate inhibitors of these isozymes abolished phosphorylation of the cytoplasmic domain, demonstrating that these kinases are responsible for the phosphorylation. Analysis of proteins specifically bound to the phosphorylated cytoplasmic tail of L-selectin revealed that PKCalpha and -theta are strongly associated with the phosphorylated cytoplasmic domain of L-selectin. Binding of these isozymes to L-selectin was also found in intact cells after phorbol ester treatment inducing serine phosphorylation of the receptor. Furthermore, stimulation of Jurkat T-cells by CD3 cross-linking induced association of PKCalpha and -theta with L-selectin, indicating a role of these kinases in the regulation of L-selectin through the T-cell receptor complex. The phosphorylation-regulated association of PKC isozymes with the cytoplasmic domain of L-selectin indicates an important role of this kinase family in L-selectin signal transduction.
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Affiliation(s)
- Karin Kilian
- Institut für Klinische Chemie und Pathobiochemie, Charité, Berlin 12200, Germany.
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32
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Allende ML, Dreier JL, Mandala S, Proia RL. Expression of the sphingosine 1-phosphate receptor, S1P1, on T-cells controls thymic emigration. J Biol Chem 2004; 279:15396-401. [PMID: 14732704 DOI: 10.1074/jbc.m314291200] [Citation(s) in RCA: 354] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
S1P(1) is a widely distributed G protein-coupled receptor whose ligand, sphingosine 1-phosphate, is present in high concentrations in the blood. The sphingosine 1-phosphate receptor-signaling pathway is believed to have potent effects on cell trafficking in the immune system. To determine the precise role of the S1P(1) receptor on T-cells, we established a T-cell-specific S1P(1) knock-out mouse. The mutant mice showed a block in the egress of mature T-cells into the periphery. The expression of the S1P(1) receptor was up-regulated in mature thymocytes, and its deletion altered the chemotactic responses of thymocytes to sphingosine 1-phosphate. The results indicated that the expression of the S1P(1) receptor on T-cells controls their exit from the thymus and entry into the blood and, thus, has a central role in regulating the numbers of peripheral T-cells.
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Affiliation(s)
- Maria L Allende
- Genetics of Development and Disease Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-1821, USA
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33
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Abstract
Diabetic retinopathy is a leading cause of adult vision loss and blindness. Earlier studies have shown that polymorphonuclear neutrophils play an important role in the pathogenesis of diabetic vascular complications. Stimulation of these cells is associated with the desquamation of L-selectin. The aim of the study was to evaluate the relationship between the serum concentration of L-selectin and the development of retinopathy in Type 2 diabetic patients. The study comprised 51 Type 2 diabetic patients, aged 65.2 +/- 7.5 years, with a diabetes duration of 10.1 +/- 8.9 years and HbA1c of 8.2 +/- 1.4. The study subjects were divided into two groups: Group A diabetic patients with retinopathy (n = 28) and Group B diabetic patients without retinopathy (n = 23). Twenty age- and sex-matched nondiabetic healthy subjects were enrolled as the control group. Patients with any inflammatory disease were excluded. Retinopathy was assessed by centrally graded retinal photographs. The serum concentration of sL-selectin was estimated using an ELISA test. We observed significantly higher serum concentrations of sL-selectin in Type 2 diabetic patients with retinopathy than in healthy subjects (36.5 +/- 18.1 vs. 11.4 +/- 7.5 ng/ml, p < 0.001). There was also a significant difference between Group A and Group B (36.5 +/- 18.1 vs. 24.2 +/- 13.5 ng/ml, p < 0.05) as well as between Group B and the controls (24.2 +/- 13.5 vs. 11.4 +/- 7.5 ng/ml, p < 0.01) with regard to sL-selectin levels. sL-selectin was significantly correlated with HbA1c (r = 0.93, p < 0.001) and with diabetes duration (r = 0.44, p < 0.001). These results suggest that there was a strong relationship between sL-selectin and diabetic retinopathy. The strong correlation between sL-selectin and HbA1c levels supports the concept that the sL-selectin level is increased with poor glycemic control, which may affect endothelial cell activity and cause subsequent microvascular complications.
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Affiliation(s)
- Koray Karadayi
- Department of Ophthalmology, Gülhane Military Medical Academy, Haydarpaşa Training Hospital, Istanbul, Turkey.
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34
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Yamaguchi M, Ishida H, Kanamori A, Kannagi R, Kiso M. Studies on the endogenous L-selectin ligands: systematic and highly efficient total synthetic routes to lactamized-sialyl 6-O-sulfo Lewis X and other novel gangliosides containing lactamized neuraminic acid. Carbohydr Res 2003; 338:2793-812. [PMID: 14667701 DOI: 10.1016/j.carres.2003.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Systematic syntheses of lactamized neuraminic acid-containing gangliosides GM4, sulfated sialylparagloboside, and sulfated/nonsulfated sialyl Lewis X are described. The highly efficient, one-step lactamization of neuraminic acid was accomplished by treatment of the N-deacetylated sialic acid (neuraminic acid)-containing gangliosides with HBTU and HOBt in DMF at 65 degrees C. Both the lactamized neuraminic acid residue and the sulfate group at O-6 of the GlcNAc residue were found to be involved in the antigenic determinant defined by G159 monoclonal antibody, while the fucose residue may not be critical for the recognition by G159 mAb.
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Affiliation(s)
- Masanori Yamaguchi
- Department of Applied Bio-organic Chemistry, Gifu University, Gifu 501-1193, Japan
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35
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Sarangapani KK, Yago T, Klopocki AG, Lawrence MB, Fieger CB, Rosen SD, McEver RP, Zhu C. Low force decelerates L-selectin dissociation from P-selectin glycoprotein ligand-1 and endoglycan. J Biol Chem 2003; 279:2291-8. [PMID: 14573602 DOI: 10.1074/jbc.m310396200] [Citation(s) in RCA: 204] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Selectin-ligand interactions mediate the tethering and rolling of circulating leukocytes on vascular surfaces during inflammation and immune surveillance. To support rolling, these interactions are thought to have rapid off-rates that increase slowly as wall shear stress increases. However, the increase of off-rate with force, an intuitive characteristic named slip bonds, is at odds with a shear threshold requirement for selectin-mediated cell rolling. As shear drops below the threshold, fewer cells roll and those that do roll less stably and with higher velocity. We recently demonstrated a low force regime where the off-rate of P-selectin interacting with P-selectin glycoprotein ligand-1 (PSGL-1) decreased with increasing force. This counter-intuitive characteristic, named catch bonds, might partially explain the shear threshold phenomenon. Because L-selectin-mediated cell rolling exhibits a much more pronounced shear threshold, we used atomic force microscopy and flow chamber experiments to determine off-rates of L-selectin interacting with their physiological ligands and with an antibody. Catch bonds were observed at low forces for L-selectin-PSGL-1 interactions coinciding with the shear threshold range, whereas slip bonds were observed at higher forces. These catch-slip transitional bonds were also observed for L-selectin interacting with endoglycan, a newly identified PSGL-1-like ligand. By contrast, only slip bonds were observed for L-selectin-antibody interactions. These findings suggest that catch bonds contribute to the shear threshold for rolling and are a common characteristic of selectin-ligand interactions.
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Affiliation(s)
- Krishna K Sarangapani
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
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36
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Abstract
L-selectin is expressed by leukocytes and facilitates their adhesion under flow along the walls of blood vessels. As do a variety of membrane proteins, L-selectin undergoes ectodomain shedding. Using approaches that monitor full-length L-selectin in short-term assays, it has been determined that L-selectin shedding is defective in tumor necrosis factor alpha-converting enzyme (ADAM-17)-deficient cells. In this study, we examined the steady-state levels of L-selectin on ADAM-17-deficient cells using a monoclonal antibody to the cytoplasmic region of L-selectin, which allows for the detection of total L-selectin (full-length and the membrane-associated cleavage fragment). We demonstrate that ADAM-17-deficient cells generate a 6-kDa transmembrane fragment of L-selectin. Although inducible L-selectin shedding by phorbol 12-myristate 13-acetate stimulation was not observed by these cells in short-term assays, basal turnover did occur, resulting in the production of soluble L-selectin, as determined by enzyme-linked immunosorbent assay. L-selectin turnover was greatly increased upon ADAM-17 reconstitution. Truncating the juxtamembrane region of L-selectin blocked ADAM-17-independent shedding as did a hydroxymate metalloprotease inhibitor. Together, these findings demonstrate that a metalloprotease activity separate from ADAM-17 can use the cleavage domain of L-selectin. We speculate that separate proteolytic mechanisms of L-selectin shedding may regulate distinct antiadhesive mechanisms, such as inducible shedding for the rapid dissociation of cell-cell interactions and constitutive shedding for the homeostatic maintenance of high serum levels of soluble L-selectin, a potential adhesion buffer.
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Affiliation(s)
- Bruce Walcheck
- Department of Veterinary PathoBiology, University of Minnesota Academic Health Center, St. Paul, MN 55108, USA.
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37
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Kannagi R. [Recent advances in the study of lymphocyte homing involving selectins and CD44]. Tanpakushitsu Kakusan Koso 2003; 48:1112-9. [PMID: 12807017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
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38
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Mitoma J, Petryniak B, Hiraoka N, Yeh JC, Lowe JB, Fukuda M. Extended core 1 and core 2 branched O-glycans differentially modulate sialyl Lewis X-type L-selectin ligand activity. J Biol Chem 2003; 278:9953-61. [PMID: 12529363 DOI: 10.1074/jbc.m212756200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It has been established that sialyl Lewis x in core 2 branched O-glycans serves as an E- and P-selectin ligand. Recently, it was discovered that 6-sulfosialyl Lewis x in extended core 1 O-glycans, NeuNAcalpha2-->3Galbeta1-->4(Fucalpha1-->3(sulfo-->6))GlcNAcbeta1--> 3Galbeta1-->3GalNAcalpha1-->Ser/Thr, functions as an L-selectin ligand in high endothelial venules. Extended core 1 O-glycans can be synthesized when a core 1 extension enzyme is present. In this study, we first show that beta1,3-N-acetylglucosaminyltransferase-3 (beta3GlcNAcT-3) is almost exclusively responsible for core 1 extension among seven different beta3GlcNAcTs and thus acts on core 1 O-glycans attached to PSGL-1. We found that transcripts encoding beta3GlcNAcT-3 were expressed in human neutrophils and lymphocytes but that their levels were lower than those of transcripts encoding core 2 beta1,6-N-acetylglucosaminyltransferase I (Core2GlcNAcT-I). Neutrophils also expressed transcripts encoding fucosyltransferase VII (FucT-VII) and Core2GlcNAcT-I, whereas lymphocytes expressed only small amounts of transcripts encoding FucT-VII. To determine the roles of sialyl Lewis x in extended core 1 O-glycans, Chinese hamster ovary (CHO) cells were stably transfected to express PSGL-1, FucT-VII, and either beta3GlcNAcT-3 or Core2GlcNAcT-I. Glycan structural analyses disclosed that PSGL-1 expressed in these transfected cells carried comparable amounts of sialyl Lewis x in extended core 1 and core 2 branched O-glycans. In a rolling assay, CHO cells expressing sialyl Lewis x in extended core 1 O-glycans supported a significant degree of shear-dependent tethering and rolling of neutrophils and lymphocytes, although less than CHO cells expressing sialyl Lewis x in core 2 branched O-glycans. These results indicate that sialyl Lewis x in extended core 1 O-glycans can function as an L-selectin ligand and is potentially involved in neutrophil adhesion on neutrophils bound to activated endothelial cells.
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Affiliation(s)
- Junya Mitoma
- Glycobiology Program, Cancer Research Center, the Burnham Institute, La Jolla, California 92037, USA
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39
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Dwir O, Steeber DA, Schwarz US, Camphausen RT, Kansas GS, Tedder TF, Alon R. L-selectin dimerization enhances tether formation to properly spaced ligand. J Biol Chem 2002; 277:21130-9. [PMID: 11907045 DOI: 10.1074/jbc.m201999200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Selectin counterreceptors are glycoprotein scaffolds bearing multiple carbohydrate ligands with exceptional ability to tether flowing cells under disruptive shear forces. Bond clusters may facilitate formation and stabilization of selectin tethers. L-selectin ligation has been shown to enhance L-selectin rolling on endothelial surfaces. We now report that monoclonal antibodies-induced L-selectin dimerization enhances L-selectin leukocyte tethering to purified physiological L-selectin ligands and glycopeptides. Microkinetic analysis of individual tethers suggests that leukocyte rolling is enhanced through the dimerization-induced increase in tether formation, rather than by tether stabilization. Notably, L-selectin dimerization failed to augment L-selectin-mediated adhesion below a threshold ligand density, suggesting that L-selectin dimerization enhanced adhesiveness only to properly clustered ligand. In contrast, an epidermal growth factor domain substitution of L-selectin enhanced tether formation to L-selectin ligands irrespective of ligand density, suggesting that this domain controls intrinsic ligand binding properties of L-selectin without inducing L-selectin dimerization. Strikingly, at low ligand densities, where L-selectin tethering was not responsive to dimerization, elevated shear stress restored sensitivity of tethering to selectin dimerization. This is the first indication that shear stress augments effective selectin ligand density at local contact sites by promoting L-selectin encounter of immobilized ligand.
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Affiliation(s)
- Oren Dwir
- Department of Immunology, Weizmann Institute of Science, Rehovot, 76100 Israel
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40
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Nicholson IC. CD62L (L-selectin). J BIOL REG HOMEOS AG 2002; 16:144-6. [PMID: 12144128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- I C Nicholson
- Child Health Research Institute, Women's and Children's Hospital, Adelaide, South Australia.
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41
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Abstract
This article reviews recent advances in the knowledge of the role of L-selectin, an adhesion molecule that is expressed on the surface of circulating leucocytes, in animal and human physiology and pathophysiology. After a brief discussion on nomenclature and structure, it progresses through the evidence for expression and regulation of L-selectin, cell collection and purification, physiological function and roles. The special role of knock out mice and monoclonal antibodies in determining a role for L-selectin in inflammatory states is described before proceeding to discuss the importance of L-selectin ligands and shed L-selectin. A second section describes a role for L-selectin in pathophysiological states in animals and man, with special reference to trauma, systemic inflammatory syndromes and sepsis. The review concludes with a summary of the potential role of anti-inflammatory medication and L-selectin blockers in the management of inflammation.
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Affiliation(s)
- Timothy H Rainer
- Accident and Emergency Medicine Academic Unit, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, Shatin, People's Republic of China.
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42
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Ivetic A, Deka J, Ridley A, Ager A. The cytoplasmic tail of L-selectin interacts with members of the Ezrin-Radixin-Moesin (ERM) family of proteins: cell activation-dependent binding of Moesin but not Ezrin. J Biol Chem 2002; 277:2321-9. [PMID: 11706008 DOI: 10.1074/jbc.m109460200] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
L-selectin regulates the recruitment of naive lymphocytes from the bloodstream to secondary lymphoid organs, mediating their initial capture and subsequent rolling along high endothelial cell surface-expressed ligands in peripheral lymph nodes. In vivo, distribution of L-selectin and cell surface levels determine the tethering efficiency and rolling velocity of leukocytes, respectively. Treatment of naive lymphocytes with phorbol myristate acetate (PMA) induces rapid ectodomain proteolytic down-regulation (shedding) of surface L-selectin via a protein kinase C (PKC)-dependent pathway. In an attempt to isolate proteins that are involved in regulating L-selectin expression, an affinity column was constructed using the 17-amino acid cytoplasmic tail of L-selectin. Affinity purification of extracts from lymphocytes, pre-treated with or without PMA, allowed identification of proteins that interact with the affinity column under one condition but not the other. By using this approach, members of the Ezrin-Radixin-Moesin family of proteins were found to interact specifically with the cytoplasmic tail of L-selectin. Moesin from PMA-stimulated lymphocytes, but not from unstimulated lymphocytes, bound to L-selectin tail. In contrast, ezrin from unstimulated or PMA-stimulated lymphocytes associated with L-selectin tail with equal affinity. Furthermore, the PKC inhibitor Ro 31-8220 significantly reduced the interaction of moesin, but not ezrin, with L-selectin. Alanine mutations of membrane-proximal basic amino acid residues in the cytoplasmic domain of L-selectin identified arginine 357 as a critical residue for both ezrin and moesin interaction. Finally, BIAcore affinity analysis confirmed that N-terminal moesin interacts specifically with L-selectin cytoplasmic tail, with relatively high affinity (K(d) approximately 40 nm). Based on these findings, although moesin and ezrin bind to a similar region of the cytoplasmic tail of L-selectin, moesin binding is dependent on PKC activation, which suggests that ezrin and moesin are regulated differently in lymphocytes.
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Affiliation(s)
- Aleksandar Ivetic
- Divisions of Cellular Immunology, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom
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43
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Dimitroff CJ, Lee JY, Schor KS, Sandmaier BM, Sackstein R. differential L-selectin binding activities of human hematopoietic cell L-selectin ligands, HCELL and PSGL-1. J Biol Chem 2001; 276:47623-31. [PMID: 11591704 DOI: 10.1074/jbc.m105997200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression of L-selectin on human hematopoietic cells (HC) is associated with a higher proliferative activity and a more rapid engraftment after hematopoietic stem cell transplantation. Two L-selectin ligands are expressed on human HCs, P-selectin glycoprotein ligand-1 (PSGL-1) and a specialized glycoform of CD44 (hematopoietic cell E- and L-selectin ligand, HCELL). Although the structural biochemistry of HCELL and PSGL-1 is well characterized, the relative capacity of these molecules to mediate L-selectin-dependent adhesion has not been explored. In this study, we examined under shear stress conditions L-selectin-dependent leukocyte adhesive interactions mediated by HCELL and PSGL-1, both as naturally expressed on human HC membranes and as purified molecules. By utilizing both Stamper-Woodruff and parallel-plate flow chamber assays, we found that HCELL displayed a 5-fold greater capacity to support L-selectin-dependent leukocyte adherence across a broad range of shear stresses compared with that of PSGL-1. Moreover, L-selectin-mediated leukocyte binding to immunopurified HCELL was consistently >5-fold higher than leukocyte binding to equivalent amounts of PSGL-1. Taken together, these data indicate that HCELL is a more avid L-selectin ligand than PSGL-1 and may be the preferential mediator of L-selectin-dependent adhesive interactions among human HCs in the bone marrow.
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Affiliation(s)
- C J Dimitroff
- Department of Dermatology, Harvard Skin Disease Research Center, Brigham and Women's Hospital, Harvard Medical School, 77 Ave. Louis Pasteur, Boston, MA 02115, USA
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44
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Fieger CB, Emig-Vollmer S, Petri T, Gräfe M, Gohlke M, Debus N, Semmler W, Tauber R, Volz B. The adhesive properties of recombinant soluble L-selectin are modulated by its glycosylation. Biochim Biophys Acta 2001; 1524:75-85. [PMID: 11078961 DOI: 10.1016/s0304-4165(00)00143-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The leukocyte adhesion molecule L-selectin, which mediates the initial steps of leukocyte attachment to vascular endothelium, is intensely glycosylated. Different glycoforms of L-selectin are expressed on different leukocyte subsets and differences in L-selectin glycosylation appear to be correlated with the leukocyte's ability to attach to different endothelial targets. In the present study we addressed the question whether glycosylation of L-selectin influences L-selectin-ligand interactions. To obtain different glycoforms of L-selectin, recombinant proteins were expressed both in the baby hamster kidney (BHK) cell line and in the human myelogenous cell line K562, resulting in sL-sel[BHK] or sL-sel[K562], respectively. The glycosylation characteristics of the purified proteins were determined. The most striking differences in glycosylation were seen in the terminal sialylation. Each of the two proteins carried sialic acids in the alpha 2-3 position, while alpha 2-6-bound sialic acids were found exclusively on sL-sel[K562]. To investigate their adhesive properties, both recombinant sL-selectins were used in cell adhesion assays and interactions with the ligands present on various hematopoietic cell lines or activated human cardiac microvascular endothelial cells were examined. The binding capacity of sL-sel[K562] was about 1.6 fold higher compared to sL-sel[BHK] under static as well as under flow conditions. These findings indicate that the terminal sialylation pattern of L-selectin modulates its binding characteristics.
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Affiliation(s)
- C B Fieger
- Institut für Klinische Chemie und Pathobiochemie, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Germany
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45
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Abstract
Among cell-adhesion molecules, L-selectin recognizes sulfated sLe(x) with relatively low affinity. Here, we aimed at artificial mimics by synthesizing a set of di- and tri-sulfated galabioses, which may surpass the affinity of sulfated sLe(x). As a strategy to obtain 3',6',6-tri-O-sulfogalabioses, regioselective reductive cleavage of 4,6- and 4',6'-di-O-benzylidenegalabioses was employed. Two suitably protected galactose precursors were conjugated to yield alpha and beta anomers (48 and 18%, respectively) by using a pentenyl galactoside donor and iodinium di-sym-collidine perchlorate as the catalyst. For synthesizing the 3',6-di-O-sulfogalabiose, however, a trichloroacetimidate donor was superior (52%) to the pentenyl one (30%).
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Affiliation(s)
- T Yoshida
- Department of Microbiology and Immunology, Aichi Medical University, 480-1195, Aichi, Japan.
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46
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Dwir O, Kansas GS, Alon R. Cytoplasmic anchorage of L-selectin controls leukocyte capture and rolling by increasing the mechanical stability of the selectin tether. J Cell Biol 2001; 155:145-56. [PMID: 11581291 PMCID: PMC2150804 DOI: 10.1083/jcb.200103042] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
L-selectin is a leukocyte lectin that mediates leukocyte capture and rolling in the vasculature. The cytoplasmic domain of L-selectin has been shown to regulate leukocyte rolling. In this study, the regulatory mechanisms by which this domain controls L-selectin adhesiveness were investigated. We report that an L-selectin mutant generated by truncation of the COOH-terminal 11 residues of L-selectin tail, which impairs association with the cytoskeletal protein alpha-actinin, could capture leukocytes to glycoprotein L-selectin ligands under physiological shear flow. However, the conversion of initial tethers into rolling was impaired by this partial tail truncation, and was completely abolished by a further four-residue truncation of the L-selectin tail. Physical anchorage of both cell-free tail-truncated mutants within a substrate fully rescued their adhesive deficiencies. Microkinetic analysis of full-length and truncated L-selectin-mediated rolling at millisecond temporal resolution suggests that the lifetime of unstressed L-selectin tethers is unaffected by cytoplasmic tail truncation. However, cytoskeletal anchorage of L-selectin stabilizes the selectin tether by reducing the sensitivity of its dissociation rate to increasing shear forces. Low force sensitivity (reactive compliance) of tether lifetime is crucial for selectins to mediate leukocyte rolling under physiological shear stresses. This is the first demonstration that reduced reactive compliance of L-selectin tethers is regulated by cytoskeletal anchorage, in addition to intrinsic mechanical properties of the selectin-carbohydrate bond.
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Affiliation(s)
- O Dwir
- Department of Immunology, Weizmann Institute of Science, Rehovot, 76100 Israel
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47
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Abstract
L-selectin (CD62L), a lectin-like adhesion molecule, mediates lymphocyte homing and leukocyte accumulation at sites of inflammation. Its transmembrane (TM) and intracellular (IC) domains confer clustering of L-selectin on microvilli of resting leukocytes, which is important for L-selectin function. Following activation of protein kinase C (PKC) or calmodulin inhibition, the wild-type (WT) protein is rapidly cleaved in its membrane-proximal ectodomain. To examine whether L-selectin topography or TM/IC domains are involved in this shedding process, we used stable transfectants expressing WT L-selectin (on microvilli) or chimeric molecules consisting of the L-selectin ectodomain linked to the TM/IC domains of CD44 (excluded from microvilli) or CD31 (randomly distributed). PKC activation by PMA altered the cells' surface morphology, but did not induce a redistribution of L-selectin ectodomains. All cell lines shed ectodomains upon PMA activation in a dose-dependent fashion and with similar kinetics. Calmodulin inhibition by trifluoperazine induced shedding in both WT and chimera transfectants. At high trifluoperazine concentrations, shedding of WT L-selectin was significantly more pronounced than that of chimeric molecules. Regardless of the activating stimulus, shedding was blocked by a hydroxamate-based metalloprotease inhibitor, suggesting that ectodomain down-regulation occurred through proteolytic cleavage by identical protease(s). These results show that the recognition site(s) for PKC-induced L-selectin shedding is exclusively contained within the ectodomain; the nature of subsurface structures and surface topography are irrelevant. Shedding induced by calmodulin inhibition has two components: one requires the L-selectin TM/IC domain, and the other is independent of it.
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Affiliation(s)
- B P Fors
- Center for Blood Research and Department of Pathology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA
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48
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Ushakova NA, Probrazhenskaia ME, Nifant'ev NE, Voznyĭ IV, Pochechueva TV, Bovin NV. [Effects of mannose derivatives on development of selectin-dependent peritoneal inflammation in rats and mice]. Vopr Med Khim 2001; 47:491-7. [PMID: 11766259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
Abstract
The inhibitory effect of mannose-containing oligosaccharides on model carbohydrate ligand interaction with E-, P- and L-selectins in vitro, as well as on the ability of these compounds to block the leukocyte extravasation in rat and mouse peritonitis in vivo was studied. The monomeric and polymeric compounds, 4-nitrophenylthiomannoside, phenylmannoside, conjugated with polyacrylic acid, and alpha-mannose, conjugated with polyacrylamide, inhibited the binding of the model ligand to P- and L-selectins (but not to E-selectin). Intravenous injection of these compounds was found to cause a dose-dependent reduction of neutrophil accumulation in rat peritoneum. The polysaccharide mannan was inactive in both types of experiments. The conjugate of phenylmannoside with polyacrylic acid was the most effective blocker as in vitro experiments, as well as in vivo. The inhibitory effect of subcutaneous injection of 4-nitrophenylthiomannoside on mouse peritonitis was demonstrated.
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Affiliation(s)
- N A Ushakova
- Orehovich Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, Pogodinskaya 10, Moscow 119992
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49
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Zhao L, Shey M, Farnsworth M, Dailey MO. Regulation of Membrane Metalloproteolytic Cleavage of L-selectin (CD62L) by the Epidermal Growth Factor Domain. J Biol Chem 2001; 276:30631-40. [PMID: 11375402 DOI: 10.1074/jbc.m103748200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The adhesion molecule L-selectin is cleaved rapidly from the surface of activated leukocytes by tumor necrosis factor-alpha converting enzyme, a cell surface metalloprotease, and also undergoes slower constitutive shedding in unactivated cells. The structural features that render it susceptible to shedding are poorly understood. We therefore analyzed the shedding of a series of mutant and chimeric L-selectin molecules. Although murine L-selectin is cleaved at a specific location in the juxtamembrane region 11 amino acids distal to the cell membrane, this cleavage has little sequence specificity. However, proline substitution at the P2' or P3' position or deletion of the epidermal growth factor (EGF) domain completely blocks the rapid phorbol ester-induced cleavage, but does not affect the slower basal proteolytic shedding. Insertion of the 15-residue membrane-proximal region (MPR) of L-selectin into the heterologous protein B7.2 results in a molecule that undergoes constitutive proteolytic turnover. In contrast, insertion of both the EGF domain and the MPR confers susceptibility to both slow constitutive shedding and the rapid proteolytic cleavage induced by phorbol 12-myristate 13-acetate. These results demonstrate that constitutive and induced L-selectin cleavage are separable processes and that the rapid phorbol ester-induced shedding requires the presence of the EGF domain, a sequence that is remote from the cleavage site.
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Affiliation(s)
- L Zhao
- Interdisciplinary Graduate Program in Immunology and the Department of Pathology, The University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
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50
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Evans E, Leung A, Hammer D, Simon S. Chemically distinct transition states govern rapid dissociation of single L-selectin bonds under force. Proc Natl Acad Sci U S A 2001; 98:3784-9. [PMID: 11274395 PMCID: PMC31130 DOI: 10.1073/pnas.061324998] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Carbohydrate--protein bonds interrupt the rapid flow of leukocytes in the circulation by initiation of rolling and tethering at vessel walls. The cell surface carbohydrate ligands are glycosylated proteins like the mucin P-selectin glycoprotein ligand-1 (PSGL-1), which bind ubiquitously to the family of E-, P-, and L-selectin proteins in membranes of leukocytes and endothelium. The current view is that carbohydrate-selectin bonds dissociate a few times per second, and the unbinding rate increases weakly with force. However, such studies have provided little insight into how numerous hydrogen bonds, a Ca(2+) metal ion bond, and other interactions contribute to the mechanical strength of these attachments. Decorating a force probe with very dilute ligands and controlling touch to achieve rare single-bond events, we have varied the unbinding rates of carbohydrate--selectin bonds by detachment with ramps of force/time from 10 to 100,000 pN/sec. Testing PSGL-1, its outer 19 aa (19FT), and sialyl Lewis(X) (sLe(X)) against L-selectin in vitro on glass microspheres and in situ on neutrophils, we found that the unbinding rates followed the same dependence on force and increased by nearly 1,000-fold as rupture forces rose from a few to approximately 200 pN. Plotted on a logarithmic scale of loading rate, the rupture forces reveal two prominent energy barriers along the unbinding pathway. Strengths above 75 pN arise from rapid detachment (<0.01 sec) impeded by an inner barrier that requires a Ca(2+) bond between a single sLe(X) and the lectin domain. Strengths below 75 pN occur under slow detachment (>0.01 sec) impeded by the outer barrier, which appears to involve an array of weak (putatively hydrogen) bonds.
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Affiliation(s)
- E Evans
- Department of Physics, University of British Columbia, Vancouver, BC, Canada V6T 2A6.
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