title: Human synovial lubricin expresses sialyl Lewis x determinant and has L-selectin ligand activity.
abstract: Lubricin (or proteoglycan 4 (PRG4)) is an abundant mucin-like glycoprotein in synovial fluid (SF) and a major component responsible for joint lubrication. In this study, it was shown that O-linked core 2 oligosaccharides (Galβ1-3(GlcNAcβ1-6)GalNAcα1-Thr/Ser) on lubricin isolated from rheumatoid arthritis SF contained both sulfate and fucose residues, and SF lubricin was capable of binding to recombinant L-selectin in a glycosylation-dependent manner. Using resting human polymorphonuclear granulocytes (PMN) from peripheral blood, confocal microscopy showed that lubricin coated circulating PMN and that it partly co-localized with L-selectin expressed by these cells. In agreement with this, activation-induced shedding of L-selectin also mediated decreased lubricin binding to PMN. It was also found that PMN recruited to inflamed synovial area and fluid in rheumatoid arthritis patients kept a coat of lubricin. These observations suggest that lubricin is able to bind to PMN via an L-selectin-dependent and -independent manner and may play a role in PMN-mediated inflammation.
authors.affiliation: Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 405 30 Gothenburg, Sweden. chunsheng.jin@medkem.gu.se
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Jin
authors.forename: Anna-Karin Hultgård
authors.initials: AK
authors.lastname: Ekwall
authors.forename: Johan
authors.initials: J
authors.lastname: Bylund
authors.forename: Lena
authors.initials: L
authors.lastname: Björkman
authors.forename: Ruby P
authors.initials: RP
authors.lastname: Estrella
authors.forename: John M
authors.initials: JM
authors.lastname: Whitelock
authors.forename: Thomas
authors.initials: T
authors.lastname: Eisler
authors.forename: Maria
authors.initials: M
authors.lastname: Bokarewa
authors.forename: Niclas G
authors.initials: NG
authors.lastname: Karlsson
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D019041:L-Selectin / Q000096:biosynthesis; D007963:Leukocytes, Mononuclear / Q000378:metabolism* / Q000473:pathology; D007983:Lewis Blood Group Antigens; D008297:Male; D008875:Middle Aged; D009844:Oligosaccharides / Q000378:metabolism*; D011485:Protein Binding; D011509:Proteoglycans / Q000378:metabolism*; D013582:Synovial Fluid / Q000378:metabolism*; D000099158:Proteoglycan 4
chemical_list: D006023:Glycoproteins; D019041:L-Selectin; D007983:Lewis Blood Group Antigens; D009844:Oligosaccharides; D011509:Proteoglycans; D000099158:Proteoglycan 4; C494219:Lewis a oligosaccharide; C419197:PRG4 protein, human