Syk contributes to PDGF-BB-mediated migration of rat aortic smooth muscle cells via MAPK pathways.
OBJECTIVE
Here we investigated the role of spleen tyrosine kinase (Syk) in the migration induced by platelet-derived growth factor (PDGF) in rat aortic smooth muscle cells (RASMC).


METHODS
Cell migration was determined using a Boyden chamber, by wound-healing, and by aortic ring assays. Activity of Syk, mitogen-activated protein kinase (MAPK), and heat shock protein 27 (HSP27) were tested using immunoblotting with kinase inhibitors and small interference RNAs.


RESULTS
PDGF-BB induced binding of Syk to the PDGFbeta receptor and increased the phosphorylation of Syk and migration in RASMC. These effects of PDGF-BB were inhibited by piceatannol, an inhibitor of Syk. PDGF-BB increased the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, p38 MAPK, and HSP27, which were significantly inhibited by piceatannol and in Syk-knockdown cells. The p38 MAPK inhibitor SB203580 and ERK1/2 inhibitor PD98059 inhibited the migration, which was further inhibited by the combination of these inhibitors. SB203580, but not PD98059, inhibited the phosphorylation of HSP27 induced by PDGF-BB in RASMC. PDGF-BB-induced migration was attenuated in HSP27-knockdown cells. Kinase inhibitors and Syk-knockdown diminished PDGF-BB-induced sprout outgrowth in the aortic ring assay.


CONCLUSIONS
These results imply that Syk is an upstream signal of the p38 MAPK/HSP27 and ERK1/2 pathways that contributes to PDGF-BB-mediated migration in RASMC.
Lee
Chang-Kwon
CK
Department of Physiology, College of Medicine, Konkuk University, Danwol-dong 322, Chungju 380-701, Republic of Korea.
Lee
Hwan Myung
HM
Kim
Hyo Jin
HJ
Park
Hyo-Jun
HJ
Won
Kyung-Jong
KJ
Roh
Hui Yul
HY
Choi
Wahn Soo
WS
Jeon
Byeong Hwa
BH
Park
Tae-Kyu
TK
Kim
Bokyung
B
D000818:Animals; D001011:Aorta; D000077214:Becaplermin; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D015151:Immunoblotting; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000201:enzymology*; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000378:metabolism / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D020574:Proto-Oncogene Proteins c-sis; D011725:Pyridines / Q000494:pharmacology; D034622:RNA Interference; D034741:RNA, Small Interfering; D051381:Rats; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000378:metabolism; D013267:Stilbenes / Q000494:pharmacology; D000072377:Syk Kinase; D014162:Transfection / Q000379:methods
D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D047908:Intracellular Signaling Peptides and Proteins; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D011725:Pyridines; D034741:RNA, Small Interfering; D013267:Stilbenes; D000077214:Becaplermin; C041525:3,3',4,5'-tetrahydroxystilbene; D011505:Protein-Tyrosine Kinases; D020797:Receptor, Platelet-Derived Growth Factor beta; D000072377:Syk Kinase; C000606898:Syk protein, rat; D020928:Mitogen-Activated Protein Kinases; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one