title: Oxidized phospholipids induce type VIII collagen expression and vascular smooth muscle cell migration.
abstract: Phenotypic switching of vascular smooth muscle cells (VSMCs) is known to play a critical role in the development of atherosclerosis. However, the factors present within lesions that mediate VSMC phenotypic switching are unclear. Oxidized phospholipids (OxPLs), including 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphorylcholine (POVPC), are active components of minimally modified low density lipoprotein and have been previously shown to induce multiple proatherogenic events in endothelial cells and macrophages, but their effects on VSMCs have been largely unexplored until recently. We previously showed that OxPLs induced phenotypic switching of VSMCs, including suppression of SMC differentiation marker genes. The goal of the present studies was to test the hypothesis that OxPLs alter extracellular matrix production and VSMC migration. Results showed that POVPC activated expression of several extracellular matrix proteins in VSMC. POVPC increased expression of type VIII collagen alpha1 chain (Col8a1) mRNA in cultured VSMCs and in vivo in rat carotid arteries by 9-fold and 4-fold, respectively. POVPC-induced activation of Col8a1 gene expression was reduced by small interfering RNA-mediated suppression of Krüppel-like factor 4 (Klf4) and Sp1, and was abolished in Klf4-knockout VSMCs. POVPC increased Klf4 binding to the Col8a1 gene promoter both in vivo in rat carotid arteries and in cultured VSMCs based on chromatin immunoprecipitation assays. Moreover, POVPC-induced VSMC migration was markedly reduced in Klf4- or type VIII collagen-knockout VSMCs. Given evidence that OxPLs are present within atherosclerotic lesions, it is interesting to suggest that OxPL-induced changes in VSMC phenotype may contribute to the pathogenesis of atherosclerosis at least in part through changes in extracellular matrix composition.
authors.affiliation: Department of Molecular Physiology and Biological Physics, University of Virginia, Robert M Berne Cardiovascular Research Center, Charlottesville, VA 22908, USA.
authors.forename: Olga A
authors.initials: OA
authors.lastname: Cherepanova
authors.forename: Nataliya A
authors.initials: NA
authors.lastname: Pidkovka
authors.forename: Olga F
authors.initials: OF
authors.lastname: Sarmento
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yoshida
authors.forename: Qiong
authors.initials: Q
authors.lastname: Gan
authors.forename: Eser
authors.initials: E
authors.lastname: Adiguzel
authors.forename: Michelle P
authors.initials: MP
authors.lastname: Bendeck
authors.forename: Judith
authors.initials: J
authors.lastname: Berliner
authors.forename: Norbert
authors.initials: N
authors.lastname: Leitinger
authors.forename: Gary K
authors.initials: GK
authors.lastname: Owens
mesh_terms: D000818:Animals; D001011:Aorta / Q000378:metabolism; D001057:Apolipoproteins E / Q000235:genetics / Q000378:metabolism; D002339:Carotid Arteries / Q000378:metabolism; D002465:Cell Movement; D002478:Cells, Cultured; D024102:Collagen Type VIII / Q000235:genetics / Q000378:metabolism*; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D010084:Oxidation-Reduction; D010641:Phenotype; D010713:Phosphatidylcholines / Q000378:metabolism; D010742:Phospholipid Ethers / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D016329:Sp1 Transcription Factor / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation
chemical_list: C400184:1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphorylcholine; C400185:1-palmitoyl-2-glutaroyl-sn-glycero-3-phosphorylcholine; D001057:Apolipoproteins E; D024102:Collagen Type VIII; C000715468:Klf4 protein, mouse; C000715469:Klf4 protein, rat; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D008077:Lipoproteins, LDL; D010713:Phosphatidylcholines; D010742:Phospholipid Ethers; D010743:Phospholipids; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D016329:Sp1 Transcription Factor; C099252:oxidized low density lipoprotein; C472349:oxidized-L-alpha-1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine