title: Identification of osteoglycin as a component of the vascular matrix. Differential expression by vascular smooth muscle cells during neointima formation and in atherosclerotic plaques.
abstract: Using differential cDNA screening, we demonstrated that the bone-associated glycoprotein osteoglycin was highly expressed in differentiated adult rat vascular smooth muscle cells (VSMCs) but downregulated in VSMCs that had undergone proliferation in vitro. Further experiments in vitro revealed that osteoglycin gene expression was downregulated by a number of cytokines expressed in vivo (often in association with vascular injury) including basic fibroblast growth factor, transforming growth factor-beta, platelet-derived growth factor, and angiotensin II. In the normal adult rat carotid artery, osteoglycin was expressed in both the media and adventitia. However, osteoglycin mRNA expression was substantially increased in the adventitia and neointima 14 days after balloon injury, implying a role for this protein in vessel remodeling. Northern analysis of mRNA from neonatal rat aortas demonstrated upregulation of osteoglycin mRNA at week 2, after VSMC proliferation had ceased and when matrix modeling was maximal. In situ hybridization studies in human coronary arteries showed that osteoglycin mRNA was expressed by normal medial VSMCs but was downregulated in a subset of intimal VSMCs. Osteoglycin was not expressed in the VSMCs of adventitial vessels but was expressed in a subset of adventitial cells. This expression pattern contrasted with that of SM22 alpha, a contractile protein marker of VSMC differentiation, which was highly expressed in the media of all vessels. These data indicate that osteoglycin is a new marker of differentiated VSMCs and may be an essential component of the normal vascular matrix.
authors.affiliation: University of Cambridge, Department of Medicine, Addenbrooke's Hospital, UK. cs131@mole.bio.cam.ac.uk
authors.forename: C M
authors.initials: CM
authors.lastname: Shanahan
authors.forename: N R
authors.initials: NR
authors.lastname: Cary
authors.forename: J K
authors.initials: JK
authors.lastname: Osbourn
authors.forename: P L
authors.initials: PL
authors.lastname: Weissberg
mesh_terms: D000595:Amino Acid Sequence; D000800:Angioplasty, Balloon / Q000009:adverse effects; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D015415:Biomarkers; D002339:Carotid Arteries / Q000378:metabolism*; D020212:Carotid Artery Injuries; D002417:Cattle; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D002645:Chickens; D003001:Cloning, Molecular; D003324:Coronary Artery Disease / Q000378:metabolism / Q000473:pathology; D003331:Coronary Vessels / Q000378:metabolism; D016207:Cytokines / Q000494:pharmacology; D018076:DNA, Complementary / Q000235:genetics; D004730:Endothelium, Vascular / Q000293:injuries / Q000473:pathology*; D005109:Extracellular Matrix / Q000737:chemistry*; D005786:Gene Expression Regulation / Q000187:drug effects; D006023:Glycoproteins / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics; D006133:Growth Substances / Q000494:pharmacology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D008840:Microfilament Proteins; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000096:biosynthesis; D009131:Muscle, Smooth, Vascular / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D016415:Sequence Alignment; D017385:Sequence Homology; D013045:Species Specificity; D017539:Tunica Intima / Q000187:drug effects / Q000293:injuries / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D016207:Cytokines; D018076:DNA, Complementary; D006023:Glycoproteins; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D008840:Microfilament Proteins; D009124:Muscle Proteins; C063488:OGN protein, human; C512906:Ogn protein, mouse; C512905:Ogn protein, rat; C058992:Tagln protein, mouse; C051615:transgelin