An essential role of the Jak-2/STAT-3/cytosolic phospholipase A(2) axis in platelet-derived growth factor BB-induced vascular smooth muscle cell motility.
Platelet-derived growth factor-BB (PDGF-BB) is a potent motogen for vascular smooth muscle cells (VSMCs). To understand its motogenic signaling events, we have studied the role of the Janus-activated kinase/signal transducers and activators of transcription (Jak/STAT) pathway and cytosolic phospholipase A(2) (cPLA(2)). PDGF-BB stimulated tyrosine phosphorylation of Jak-2 and STAT-3 in a time-dependent manner in VSMCs. In addition, AG490 and Jak-2KEpRK5, a selective pharmacological inhibitor and a dominant negative mutant, respectively, of Jak-2, attenuated PDGF-BB-induced STAT-3 tyrosine phosphorylation and its DNA binding and reporter gene activities. PDGF-BB induced VSMC motility in a dose-dependent manner with a maximum effect at 10 ng/ml. Dominant negative mutant-dependent suppression of Jak-2 and STAT-3 blocked PDGF-BB-induced VSMC motility. PDGF-BB induced the expression of cPLA(2) in a Jak-2/STAT-3-dependent manner, and pharmacological inhibitors of cPLA(2) prevented PDGFBB-induced VSMC motility. Furthermore, either exogenous addition of arachidonic acid or forced expression of cPLA(2) rescued PDGF-BB-induced VSMC motility from inhibition by blockade of Jak-2 and STAT-3 activation. Together, these results for the first time show that PDGF-BB-induced VSMC motility requires activation of the Jak-2/STAT-3/cPLA(2) signaling axis.
Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA.
Indira
I
Neeli
Zhimin
Z
Liu
Nagadhara
N
Dronadula
Z Alex
ZA
Ma
Gadiparthi N
GN
Rao
D000818:Animals; D000077214:Becaplermin; D002465:Cell Movement / Q000187:drug effects; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000502:physiology*; D053614:Janus Kinase 2; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D010741:Phospholipases A / Q000502:physiology*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D020574:Proto-Oncogene Proteins c-sis; D051381:Rats; D017207:Rats, Sprague-Dawley; D050796:STAT3 Transcription Factor; D015534:Trans-Activators / Q000502:physiology*
D004268:DNA-Binding Proteins; D010982:Platelet-Derived Growth Factor; D011518:Proto-Oncogene Proteins; D020574:Proto-Oncogene Proteins c-sis; D050796:STAT3 Transcription Factor; C494088:Stat3 protein, rat; D015534:Trans-Activators; D000077214:Becaplermin; D004247:DNA; D011505:Protein-Tyrosine Kinases; C507927:Jak2 protein, rat; D053614:Janus Kinase 2; D010741:Phospholipases A