The antiarrhythmic peptide rotigaptide (ZP123) increases connexin 43 protein expression in neonatal rat ventricular cardiomyocytes.
Rotigaptide (formerly ZP123) is a novel antiarrhythmic peptide that prevents uncoupling of connexin 43 (Cx43)-mediated, gap junction communication during acute metabolic stress. Since rotigaptide's long-term effects on Cx43 are unknown, we studied its effect on Cx43 protein levels at 24 h in neonatal ventricular myocytes. As determined by Western blot analysis, rotigaptide produced a dose-dependent increase in Cx43 protein expression that reached a maximum level at 100 nM. Furthermore, 100 nM rotigaptide markedly increased Cx43 immunoreactivity and Cx43-positive gap junctions as observed in immunocytochemical studies. Cycloheximide, an inhibitor of protein synthesis, was used to investigate rotigaptide's mechanism of action. Cycloheximide (10 microg/ml) reduced Cx43 protein levels to 39% of vehicle (17 mM ethanol) whereas cotreatment of 10 microg/ml cycloheximide with 100 nM rotigaptide reduced Cx43 protein levels to 56% of vehicle. Our findings suggest that rotigaptide's effect on Cx43 expression is partly due to increased biosynthesis.
Stahlhut
Martin
M
Zealand Pharma, Glostrup, Denmark.
Petersen
Jørgen S
JS
Hennan
James K
JK
Ramirez
M Teresa
MT
D000818:Animals; D000831:Animals, Newborn; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D018031:Connexin 43 / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D017629:Gap Junctions / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism* / Q000648:ultrastructure; D009842:Oligopeptides / Q000494:pharmacology*; D014176:Protein Biosynthesis / Q000187:drug effects*; D051571:Protein Kinase C-alpha / Q000378:metabolism; D051744:Protein Kinase C-epsilon / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D000889:Anti-Arrhythmia Agents; D018031:Connexin 43; D009842:Oligopeptides; D011500:Protein Synthesis Inhibitors; D003513:Cycloheximide; D051571:Protein Kinase C-alpha; D051744:Protein Kinase C-epsilon; C477643:rotigaptide