Blood lipid mediator sphingosine 1-phosphate potently stimulates platelet-derived growth factor-A and -B chain expression through S1P1-Gi-Ras-MAPK-dependent induction of Kruppel-like factor 5.
Platelet-derived growth factors (PDGFs), potent mitogens and chemoattractants for mesenchymal cell types, play essential roles in development of several organs including blood vessels, kidney, and lung, and are also implicated in the pathogenesis of atherosclerosis and malignancies. Blood lipid mediator sphingosine 1-phosphate (S1P) regulates migration, proliferation, and apoptosis in a variety of cell types through multiple G protein-coupled receptors of the Edg family, and is necessary for vascular formation at the developmental stage. We found in the present study that S1P induced severalfold increases in the mRNA and protein levels of PDGF-A and -B chains in vascular smooth muscle cells and neointimal cells. S1P stimulation of PDGF mRNA and protein expression was abolished by the small interfering RNA duplexes targeting S1P(1)/Edg1 receptor subtype. S1P stimulated the small GTPase Ras in a G(i)-dependent manner, and activated ERK and p38 MAPK in G(i)- and Ras-dependent manners. Pertussis toxin pretreatment, adenovirus-mediated Asn(17)Ras expression, the MEK inhibitor PD98059, or the p38 MAPK inhibitor SB203580 markedly suppressed PDGF mRNA and protein up-regulation, indicating the involvement of G(i)-Ras-ERK/p38 MAPK in S1P stimulation of PDGF expression. S1P stimulated expression of the transcription factor KLF5 in manners dependent on G(i), Ras, and ERK/p38 MAPK. Down-regulation of KLF5 by small interfering RNA duplexes abolished S1P-induced PDGF-A and -B chain expression. On the other hand, overexpression of KLF5 stimulated basal and S1P-induced PDGF expression. Either S1P stimulation or KLF5 overexpression increased the PDGF-B promoter activity in a cis-element-dependent manner. These results reveal the S1P(1)-triggered, G(i)-Ras-ERK/p38 MAPK-KLF5-dependent, stimulatory regulation of PDGF gene transcription in vascular smooth muscle cells.
Usui
Soichiro
S
Department of Molecular and Cellular Physiology, Kanazawa University Graduate School of Medical Sciences, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan.
Sugimoto
Naotoshi
N
Takuwa
Noriko
N
Sakagami
Satoru
S
Takata
Shigeo
S
Kaneko
Shuichi
S
Takuwa
Yoh
Y
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D000831:Animals, Newborn; D001011:Aorta / Q000473:pathology; D017209:Apoptosis; D015152:Blotting, Northern; D015153:Blotting, Western; D002455:Cell Division; D002465:Cell Movement; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D018014:Gene Transfer Techniques; D051741:Kruppel-Like Transcription Factors; D050356:Lipid Metabolism; D008246:Lysophospholipids / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008954:Models, Biological; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000166:cytology; D010957:Plasmids / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D020574:Proto-Oncogene Proteins c-sis / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism*; D013997:Time Factors; D015534:Trans-Activators / Q000737:chemistry*; D014158:Transcription, Genetic; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases
D004791:Enzyme Inhibitors; D005419:Flavonoids; C492215:Klf5 protein, rat; D051741:Kruppel-Like Transcription Factors; D008246:Lysophospholipids; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger; D015534:Trans-Activators; C075278:platelet-derived growth factor A; C060506:sphingosine 1-phosphate; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D013110:Sphingosine; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one