Fluid shear stress stimulates platelet-derived growth factor expression in endothelial cells.
Fluid flow and the associated shear stress play a critical role in vascular growth and remodeling. Recent data suggest that increased endothelial cell expression of platelet-derived growth factor (PDGF) A- and B-chain by flow may participate in these events. In the present study, we examined the mechanism for flow-induced PDGF expression, focusing on protein kinase C (PKC). Bovine aortic endothelial cells were exposed to flow (shear stress = 30 dyn/cm2) in a parallel-plate flow chamber. Increases in PDGF B-chain, but not PDGF A-chain, were observed within 3 h, maximal within 6 h (13-fold increase), and sustained for 24 h. PKC appeared to be involved because phorbol 12-myristate 13-acetate induced PDGF B-chain mRNA. Activation of PKC alone, however, was insufficient to induce PDGF mRNA because the selective PKC activator, 1-oleoyl-2-acetyl-sn-glycerol, did not induce PDGF expression. A PKC-independent pathway was suggested by the fact that inhibition of PKC (downregulation with phorbol 12,13-dibutyrate or exposure to staurosporine) failed to block PMA or flow-induced PDGF B-chain expression. These results demonstrate flow-induced PDGF B-chain expression in endothelial cells that appears to be mediated, in part, by a PKC-independent pathway.
Mitsumata
M
M
School of Mechanical Engineering, Georgia Institute of Technology, Atlanta 30332-0405.
Fishel
R S
RS
Nerem
R M
RM
Alexander
R W
RW
Berk
B C
BC
D000818:Animals; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D010982:Platelet-Derived Growth Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D013314:Stress, Mechanical
D010982:Platelet-Derived Growth Factor; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D011493:Protein Kinase C