Role of protein kinase C-epsilon in hypertrophy of cultured neonatal rat ventricular myocytes.
Using adenovirus (Adv)-mediated overexpression of constitutively active (ca) and dominant-negative (dn) mutants, we examined whether protein kinase C (PKC)-epsilon, the major novel PKC isoenzyme expressed in the adult heart, was necessary and/or sufficient to induce specific aspects of the hypertrophic phenotype in low-density, neonatal rat ventricular myocytes (NRVM) in serum-free culture. Adv-caPKC-epsilon did not increase cell surface area or the total protein-to-DNA ratio. However, cell shape was markedly affected, as evidenced by a 67% increase in the cell length-to-width ratio and a 17% increase in the perimeter-to-area ratio. Adv-caPKC-epsilon also increased atrial natriuretic factor (ANF) and beta-myosin heavy chain (MHC) mRNA levels 2.5 +/- 0.3- and 2.1 +/- 0.2-fold, respectively, compared with NRVM infected with an empty, parent vector (P < 0.05 for both). Conversely, Adv-dnPKC-epsilon did not block endothelin-induced increases in cell surface area, the total protein-to-DNA ratio, or upregulation of beta-MHC and ANF gene expression. However, the dominant-negative inhibitor markedly suppressed endothelin-induced extracellular signal-regulated kinase (ERK) 1/2 activation. Taken together, these results indicate that caPKC-epsilon overexpression alters cell geometry, producing cellular elongation and remodeling without a significant, overall increase in cell surface area or total protein accumulation. Furthermore, PKC-epsilon activation and downstream signaling via the ERK cascade may not be necessary for cell growth, protein accumulation, and gene expression changes induced by endothelin.
Strait
J B
JB
Department of Physiology, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois 60153, USA.
Martin
J L
JL
Bayer
A
A
Mestril
R
R
Eble
D M
DM
Samarel
A M
AM
D000256:Adenoviridae / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000235:genetics; D006332:Cardiomegaly / Q000378:metabolism / Q000473:pathology; D048429:Cell Size / Q000502:physiology; D002478:Cells, Cultured; D019332:Endothelin-1 / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006352:Heart Ventricles / Q000166:cytology / Q000201:enzymology; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D018485:Muscle Fibers, Skeletal / Q000166:cytology* / Q000201:enzymology*; D016296:Mutagenesis / Q000502:physiology; D009206:Myocardium / Q000166:cytology* / Q000201:enzymology*; D018995:Myosin Heavy Chains / Q000378:metabolism; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D051744:Protein Kinase C-epsilon; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D019332:Endothelin-1; D007527:Isoenzymes; D012333:RNA, Messenger; D009320:Atrial Natriuretic Factor; C497257:Prkce protein, rat; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon; D020928:Mitogen-Activated Protein Kinases; D018995:Myosin Heavy Chains