Myocardial ischemia-reperfusion enhances transcriptional expression of endothelin-1 and vasoconstrictor ETB receptors via the protein kinase MEK-ERK1/2 signaling pathway in rat.
BACKGROUND
Coronary artery remodelling and vasospasm is a complication of acute myocardial ischemia and reperfusion. The underlying mechanisms are complex, but the vasoconstrictor peptide endothelin-1 is suggested to have an important role. This study aimed to determine whether the expression of endothelin-1 and its receptors are regulated in the myocardium and in coronary arteries after experimental ischemia-reperfusion. Furthermore, we evaluated whether treatment with a specific MEK1/2 inhibitor, U0126, modified the expression and function of these proteins.


RESULTS
Sprague-Dawley rats were randomly divided into three groups: sham-operated, ischemia-reperfusion with vehicle treatment and ischemia-reperfusion with U0126 treatment. Ischemia was induced by ligating the left anterior descending coronary artery for 30 minutes followed by reperfusion. U0126 was administered before ischemia and repeated 6 hours after start of reperfusion. The contractile properties of isolated coronary arteries to endothelin-1 and sarafotoxin 6c were evaluated using wire-myography. The gene expression of endothelin-1 and endothelin receptors were measured using qPCR. Distribution and localization of proteins (pERK1/2, prepro-endothelin-1, endothelin-1, and endothelin ETA and ETB receptors) were analysed by Western blot and immunohistochemistry. We found that pERK1/2 was significantly augmented in the ischemic area 3 hours after ischemia-reperfusion; this correlated with increased ETB receptor and ET-1 gene expressions in ischemic myocardium and in coronary arteries. ETB receptor-mediated vasoconstriction was observed to be increased in coronary arteries 24 hours after ischemia-reperfusion. Treatment with U0126 reduced pERK1/2, expression of ET-1 and ETB receptor, and ETB receptor-mediated vasoconstriction.


CONCLUSIONS
These findings suggest that the MEK-ERK1/2 signaling pathway is important for regulating endothelin-1 and ETB receptors in myocardium and coronary arteries after ischemia-reperfusion in the ischemic region. Inhibition of the MEK-ERK1/2 pathway may provide a novel target for reducing ischemia-reperfusion damage in the heart.
Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, University of Copenhagen, Glostrup, Denmark.
Gry Freja
http://orcid.org/0000-0002-3652-8507
GF
Skovsted
Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, University of Copenhagen, Glostrup, Denmark.
Lars Schack
LS
Kruse
Department of Biomedical Sciences, Cellular and Metabolic Research Section, University of Copenhagen, Copenhagen, Denmark.
Lukas Adrian
LA
Berchtold
Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, University of Copenhagen, Glostrup, Denmark.
Anne-Sofie
AS
Grell
Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, University of Copenhagen, Glostrup, Denmark.
Karin
K
Warfvinge
Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, University of Copenhagen, Glostrup, Denmark.|Department of Medicine, Institute of Clinical Sciences in Lund, Lund University, Lund, Sweden.
Lars
L
Edvinsson
D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D019332:Endothelin-1 / Q000096:biosynthesis* / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology* / Q000628:therapy; D015428:Myocardial Reperfusion Injury / Q000473:pathology* / Q000628:therapy; D009570:Nitriles / Q000494:pharmacology; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D044023:Receptor, Endothelin B / Q000096:biosynthesis* / Q000235:genetics; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014757:Viper Venoms / Q000494:pharmacology
D002070:Butadienes; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D009570:Nitriles; D044023:Receptor, Endothelin B; C113580:U 0126; D014662:Vasoconstrictor Agents; D014757:Viper Venoms; C057354:sarafotoxins s6; D048049:Extracellular Signal-Regulated MAP Kinases