Growth-promoting effect of platelet-derived growth factor on rat cardiac myocytes.
Platelet-derived growth factor (PDGF) is a dimeric molecule consisting of disulfide-bonded A- and B-polypeptide chains. Homodimeric (PDGF-AA, PDGF-BB) as well as heterodimeric (PDGF-AB) isoforms exert their effects on target cells by binding with different specificities to two structurally related protein tyrosine kinase receptors, denoted alpha- and beta-receptors. PDGF stimulates growth in various cell types, but little is known about its effect on mammalian cardiomyocytes. Therefore, growth-promoting effect of PDGF on rat cardiomyocytes was investigated. Primary culture of neonatal rat ventricular myocytes was prepared and cellular growth was estimated by [3H]-leucine incorporation assay. Tyrosine-phosphorylated PDGF-beta receptor of cardiomyocytes was determined by immunoblotting analysis after immunoprecipitation. PDGF-beta receptor, extracellular signal-regulated kinase (ERK) 1/2 and phosphorylated ERK1/2 of cardiomyocytes were measured by immunoblotting analysis. [3H]-leucine incorporation into the cultured myocytes was increased in a time- and dose-dependent manner after PDGF-BB stimulation. Phosphorylation of PDGF-beta receptor and ERK1/2 in cardiomyocytes was increased after short-term stimulation of PDGF-BB. Protein expression of PDGF-beta receptor and ERK1/2 was increased after long-term stimulation of PDGF-BB. [(3)H]-leucine incorporation into the cultured myocytes induced by PDGF-BB was partly blocked by mitogen-activated ERK-activating kinase (MEK) inhibitor PD98059, phospholipase C (PLC) inhibitor U73122, and protein kinase C (PKC) inhibitor staurosporin aglycone, respectively. Therefore, PDGF beta receptor, ERK1/2, PLC and PKC are involved in the signal transduction of PDGF-induced growth response of rat cardiac myocytes.
Liu
Jie
J
Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing 100083, China. pathophy@bjmu.edu.cn
Wu
Li-ling
LL
Li
Li
L
Zhang
Liang
L
Song
Zong-En
ZE
D000818:Animals; D000831:Animals, Newborn; D000077214:Becaplermin; D002458:Cell Fractionation; D048708:Cell Growth Processes / Q000187:drug effects*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D005419:Flavonoids / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D011500:Protein Synthesis Inhibitors / Q000378:metabolism; D020574:Proto-Oncogene Proteins c-sis; D051381:Rats; D017208:Rats, Wistar; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000378:metabolism
D005419:Flavonoids; D010982:Platelet-Derived Growth Factor; D011500:Protein Synthesis Inhibitors; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin; D020797:Receptor, Platelet-Derived Growth Factor beta; D048049:Extracellular Signal-Regulated MAP Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one