Opposing effects of delta- and zeta-protein kinase C isozymes on cardiac fibroblast proliferation: use of isozyme-selective inhibitors.
Neonatal primary cardiac fibroblasts in defined medium continue to proliferate. Here, we show that phorbol ester inhibited and transforming growth factor-beta1 (TGFbeta1) stimulated this fibroblast proliferation. Cardiac fibroblasts contain six protein kinase C (PKC) isozymes: alpha-, delta-, epsilon-, betaI-, betaII-, and zeta-PKC. To evaluate the effect of different PKC isozymes on the proliferation of these cells, we used isozyme-selective PKC inhibitors. Inhibition of endogenous delta-PKC with deltaV1-1, an isozyme-selective translocation inhibitor, resulted in increased basal thymidine incorporation by 58 +/- 12% of control cells, but did not affect TGFbeta1-induced cell growth. Inhibition of endogenous zeta-PKC in neonatal rat cardiac fibroblasts with zeta-pseudosubstrate, a selective inhibitor for the atypical PKC isozymes, revealed an opposite effect; this inhibitor reduced basal growth to 45 +/- 11% and TGFbeta1-induced growth to 61 +/- 10%. Other isozyme-specific inhibitors used in this study did not alter basal or TGFbeta1-stimulated fibroblast growth. Taken together, our data provide evidence that delta-PKC inhibits and zeta-PKC stimulates proliferation of neonatal rat cardiac fibroblasts.
Braun
Martin Ulrich
MU
Department of Molecular Pharmacology, Stanford University School of Medicine, 269 Campus Drive, CCSR 3145, Stanford, CA 94305-5332, USA.
Mochly-Rosen
Daria
D
D000818:Animals; D000831:Animals, Newborn; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism*; D006352:Heart Ventricles / Q000166:cytology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D051745:Protein Kinase C-delta; D051381:Rats; D017207:Rats, Sprague-Dawley; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D053773:Transforming Growth Factor beta1
D016895:Culture Media, Serum-Free; D004791:Enzyme Inhibitors; D007527:Isoenzymes; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C497260:Prkcd protein, rat; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D013755:Tetradecanoylphorbol Acetate