Phenotypic modulation of vascular smooth muscle cells induced by unsaturated lysophosphatidic acids.
The phenotypic modulation of vascular smooth muscle cells (VSMCs) from the differentiated state to the dedifferentiated one is critically involved in the development and progression of atherosclerosis. Although many cytokines and growth factors have been reported as atherogenic factors, the critical pathogens for inducing atherosclerosis remain unknown, largely because proper examining systems of them have not been developed. We recently established primary culture systems for visceral SMCs and VSMCs in which both SMCs, when cultured on laminin with insulin-like growth factor-I, show a differentiated phenotype, as indicated by a spindle-like shape, ligand-induced contractility, and a high level of SMC differentiation marker gene expression. In this study, we searched for critical dedifferentiation factors for these SMCs using our culture system. We found that polar lipids extracted from human serum markedly induced VSMC dedifferentiation, and this activity was solely present in the lysophosphatidic acid (LPA) fraction. Among several LPA species detected in human serum lipids, unsaturated LPAs were identified as major contributors to the induction of VSMC dedifferentiation. Signaling and phenotype analyses revealed that unsaturated LPA-induced VSMC dedifferentiation is mediated through the coordinated activation of extracellular signal-regulated kinase and p38 mitogen-activated protein kinase. Thus, this report demonstrates the first finding that unsaturated LPAs, but not saturated LPAs, specifically induce VSMC phenotypic modulation, suggesting that these molecules could function as atherogenic factors.
Hayashi
K
K
Department of Neuroscience, Osaka University Graduate School of Medicine, Osaka, Japan.
Takahashi
M
M
Nishida
W
W
Yoshida
K
K
Ohkawa
Y
Y
Kitabatake
A
A
Aoki
J
J
Arai
H
H
Sobue
K
K
D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D002855:Chromatography, Thin Layer; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006133:Growth Substances / Q000494:pharmacology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007797:Laminin / Q000494:pharmacology; D008246:Lysophospholipids / Q000097:blood / Q000302:isolation & purification / Q000494:pharmacology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects*; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000235:genetics; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; D015398:Signal Transduction / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases
D004791:Enzyme Inhibitors; D006133:Growth Substances; D007797:Laminin; D008246:Lysophospholipids; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; D007334:Insulin-Like Growth Factor I; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases