title: A possible suppressive role of galectin-3 in upregulated osteoclastogenesis accompanying adjuvant-induced arthritis in rats.
abstract: Galectin-3 is a beta-galactoside-binding animal lectin having pleiotropic effects on cell growth, differentiation, and apoptosis. This lectin has been shown to be involved in phagocytosis by macrophages and in inflammation. Here we investigated an involvement of galectin-3 in the regulatory process of inflammatory bone resorption in rats with adjuvant-induced arthritis (AA rats) accompanying severe bone destruction in the ankle joints. The protein level of galectin-3 in the ankle-joint extracts was markedly augmented at week 3 after adjuvant injection, at the time when severe bone destruction was observed. Immunohistochemical analysis revealed an extremely high expression of galectin-3 in macrophages and granulocytes infiltrated in the area of severe bone destruction. To estimate the role of galectin-3 in osteoclastogenesis and osteoclastic bone resorption, recombinant galectin-3 was added to in vitro culture systems. Galectin-3 markedly inhibited the formation of osteoclasts in cultures of murine osteoclast precursor cell line as well as in rat bone marrow culture systems. This inhibition was not observed by heat-inactivated galectin-3 or by galectin-7. Although recombinant galectin-3 did not affect signaling through mitogen-activated protein kinase (MAPK) or nuclear factor-kappaB (NF-kappaB), it specifically suppressed the induction of nuclear factor of activated T-cells c1 (NFATc1). Galectin-3 significantly inhibited dentine resorption by mature osteoclasts in vitro. Furthermore, in vivo studies clearly showed a significant suppression of bone destruction and osteoclast recruitment accompanying arthritis, when galectin-3 was injected into the cavity of ankle joint of AA rats. Thus, abundant galectin-3 observed in the area of severe bone destruction may act as a negative regulator for the upregulated osteoclastogenesis accompanying inflammation to prevent excess bone destruction.
authors.affiliation: Department of Hard Tissue Regeneration Control and Science, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.
authors.forename: Yin-Ji
authors.initials: YJ
authors.lastname: Li
authors.forename: Akiko
authors.initials: A
authors.lastname: Kukita
authors.forename: Junpei
authors.initials: J
authors.lastname: Teramachi
authors.forename: Kengo
authors.initials: K
authors.lastname: Nagata
authors.forename: Zhou
authors.initials: Z
authors.lastname: Wu
authors.forename: Akifumi
authors.initials: A
authors.lastname: Akamine
authors.forename: Toshio
authors.initials: T
authors.lastname: Kukita
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000378:metabolism* / Q000473:pathology*; D001854:Bone Marrow Cells / Q000166:cytology; D001862:Bone Resorption / Q000517:prevention & control; D050260:Carbohydrate Metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D037502:Galectin 3 / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D007270:Injections, Intra-Articular; D008297:Male; D050778:NFATC Transcription Factors / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D010010:Osteoclasts / Q000473:pathology*; D053245:RANK Ligand / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D011917:Rats, Inbred Lew; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology; D012720:Severity of Illness Index; D013234:Stem Cells / Q000166:cytology; D013977:Tibia / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D037502:Galectin 3; D050778:NFATC Transcription Factors; D053245:RANK Ligand; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha