Evidence for the role of protein kinase C in astrocyte-induced proliferation of rat cerebromicrovascular endothelial cells.
The proliferation of cerebral endothelial cells is a crucial step in neural angiogenesis and is a process responsive to changes in the surrounding environment. Serum-free medium conditioned by rat cortical astrocytes was found to accelerate DNA synthesis, induce transient activation of protein kinase C (PKC), and increase the endogenous phosphorylation of the PKC-specific substrate, the 85 kDa MARCKS protein, in rat cerebromicrovascular endothelial cells (RCEC). The stimulatory factor(s) in astrocyte conditioned media (ACM) were heat- and trypsin-sensitive and found to have an apparent molecular weight greater than 10 kDa. The potent PKC activator, 12-O-tetradecanoyl phorbol 13-acetate (TPA), also stimulated RCEC proliferation, whereas the inhibition of PKC by staurosporine caused a concomitant loss in ACM-induced PKC translocation, MARCKS protein phosphorylation and DNA synthesis. These findings implicate PKC activation as a critical early event in cerebral endothelial cell proliferation triggered by astrocyte-derived mitogen(s).
Stanimirovic
D B
DB
Institute for Biological Sciences, National Research Council of Canada, Ottawa, ONT, Canada.
Ball
R
R
Durkin
J P
JP
D000818:Animals; D001253:Astrocytes / Q000502:physiology*; D002455:Cell Division / Q000502:physiology; D002560:Cerebrovascular Circulation; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism; D004789:Enzyme Activation; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010766:Phosphorylation; D011493:Protein Kinase C / Q000502:physiology*; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D016895:Culture Media, Serum-Free; D047908:Intracellular Signaling Peptides and Proteins; C000619712:Marcks protein, rat; D008565:Membrane Proteins; D011506:Proteins; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D004247:DNA; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate