Mechanisms of myocardial remodeling: ramiprilat blocks the expressional upregulation of protein kinase C-epsilon in the surviving myocardium early after infarction.
Inhibition of angiotensin-converting enzyme (ACEI) after myocardial infarction reduces remodeling of the surviving myocardium. The cellular signaling mechanisms contributing to remodeling are not fully elucidated. Goal of the current study was to test whether protein kinase C (PKC) is regulated in the surviving myocardium shortly after infarction and whether this regulation is influenced by ACEI. Rats were subjected to anterior wall myocardial infarction in vivo or sham operation. After 15-45 min, mRNA levels and protein expression of the major cardiac PKC isoforms were measured in the ischemic and the remote myocardium. The influence of ACEI on PKC was tested by pretreating the rats with ramiprilat. In the ischemic region of the myocardium, a significant increase of the mRNA for PKC-delta and PKC-epsilon was observed in close correlation with increased isoform protein expression. In the surviving, remote myocardium, however, only PKC-epsilon expression was significantly augmented both at the mRNA level (158%) and at the protein level (149%). PKC-delta and PKC-alpha were unchanged. Treatment with ramiprilat could abolish this isoform-specific PKC regulation in both areas. These data characterize for the first time an isoform-specific transcriptional regulation process of PKC in the surviving myocardium after infarction. This induction of PKC-epsilon can be prevented by ACEI. It is speculated that PKC-epsilon plays a role in the signal transduction of early remodeling after infarction.
Simonis
Gregor
G
Department of Cardiology, Dresden University of Technology, Dresden, Germany.
Braun
Martin U
MU
Kirrstetter
Matthias
M
Schön
Steffen P
SP
Strasser
Ruth H
RH
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D003331:Coronary Vessels; D007527:Isoenzymes / Q000096:biosynthesis; D008026:Ligation; D008297:Male; D009203:Myocardial Infarction / Q000201:enzymology*; D011493:Protein Kinase C / Q000096:biosynthesis*; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D012333:RNA, Messenger / Q000096:biosynthesis; D017257:Ramipril / Q000031:analogs & derivatives* / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation; D020257:Ventricular Remodeling / Q000187:drug effects*
D000806:Angiotensin-Converting Enzyme Inhibitors; D007527:Isoenzymes; D012333:RNA, Messenger; C052549:ramiprilat; C497260:Prkcd protein, rat; C497257:Prkce protein, rat; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D017257:Ramipril