title: Confocal microscopy demonstrates association of LTBP-2 in fibrillin-1 microfibrils and colocalisation with perlecan in the disc cell pericellular matrix.
abstract: Comparative immunolocalisations of latent transforming growth factor-beta-1 binding protein (LTBP)-2, fibrillin-1, versican and perlecan were undertaken in foetal human and wild type C57BL/6 mouse and Hspg2 exon 3 null HS deficient mouse intervertebral discs (IVDs). LTBP-2 was a prominent pericellular component of annular fibrochondrocytes in the posterior annulus fibrosus (AF), interstitial matrix adjacent to nucleus pulposus (NP) cells and to fibrillar and cell associated material in the anterior AF of the human foetal IVD and also displayed a pericellular localisation pattern in murine IVDs. Perlecan and LTBP-2 displayed strong pericellular colocalisation patterns in the posterior AF and to fibrillar material in the outer anterior AF in the foetal human IVD. Versican was a prominent fibril-associated component in the posterior and anterior AF, localised in close proximity to fibrillin-1 in fibrillar arrangements in the cartilaginous vertebral rudiments around paraspinal blood vessels, to major collagen fibre bundles in the anterior and posterior AF and shorter fibres in the NP. Fibrillin-1 was prominent in the outer anterior AF of the human foetal IVD and in fibres extending from the AF into the cartilaginous vertebral rudiments. LTBP-2 was prominently associated with annular fibrils containing fibrillin-1, versican was localised in close proximity to these but not specifically with LTBP-2. The similar deposition levels of LTBP-2 observed in the AF of the Hspg2 exon 3 null and wild type murine IVDs indicated that perlecan HS was not essential for LTBP-2 deposition but colocalisation of LTBP-2 with perlecan in the foetal human IVD was consistent with HS mediated interactions which have already been demonstrated in-vitro.
authors.affiliation: Confocal Microscopy Unit, Preclinical Building, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, Wales, UK.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Hayes
authors.affiliation: School of Medical Sciences, University of Adelaide, Adelaide, SA, Australia.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Gibson
authors.affiliation: The Raymond Purves Research Labs, Institute of Bone and Joint Research, Kolling Institute of Medical Research, University of Sydney, The Royal North Shore Hospital of Sydney, St. Leonards, NSW, Australia.
authors.forename: Cindy
authors.initials: C
authors.lastname: Shu
authors.affiliation: The Raymond Purves Research Labs, Institute of Bone and Joint Research, Kolling Institute of Medical Research, University of Sydney, The Royal North Shore Hospital of Sydney, St. Leonards, NSW, Australia. Electronic address: james.melrose@sydney.edu.au.
authors.forename: James
authors.initials: J
authors.lastname: Melrose
mesh_terms: D000818:Animals; D002356:Cartilage / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D000071838:Fibrillin-1; D000071837:Fibrillins; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism*; D006801:Humans; D007403:Intervertebral Disc / Q000378:metabolism*; D053779:Latent TGF-beta Binding Proteins / Q000378:metabolism*; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D020894:Microfibrils / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism*; D018613:Microscopy, Confocal / Q000379:methods; D054392:Adipokines
chemical_list: D016326:Extracellular Matrix Proteins; D000071838:Fibrillin-1; D000071837:Fibrillins; D019812:Heparan Sulfate Proteoglycans; D053779:Latent TGF-beta Binding Proteins; D008840:Microfilament Proteins; C000605722:FBN1 protein, human; D054392:Adipokines; C000605724:Fbn1 protein, mouse; C509035:LTBP2 protein, human; C509036:Ltbp2 protein, mouse; C071927:perlecan
keywords: Fibrillin-1; LTBP-2; Perlecan; Versican