Inhibition of activated ERK1/2 and JNKs improves vascular function in mouse aortae in the absence of nitric oxide.
Activation of mitogen-activated protein kinases (MAPKs) is important for vascular contraction. Decreased nitric oxide availability combined with activation of MAPKs contributes to an increase in vascular tone. In this study, we have determined the involvement of extracellular signal-regulated kinases1/2 (ERK1/2) and c-Jun N-terminal kinases (JNKs) in reactivity of mouse aortae in the absence of nitric oxide. Additionally, we have examined the contribution of these kinases to endothelium-dependent and prostaglandin F(2α) (PGF(2α))-induced contractions. Precontracted aortic rings were treated with MAPK/ERK kinase1/2 (MEK1/2) inhibitor U0126 or JNKs inhibitor SP600125 to determine reactivity after inhibition of nitric oxide synthase using organ bath chambers. Additionally, rings were pretreated with or without these inhibitors to assess PGF(2α)- and acetylcholine-induced, endothelium-dependent contractions. Specificity of the inhibitors was evaluated in each aortic ring by determining the phosphorylation levels of ERK1/2 and c-Jun using Bio-Plex™ phospho-protein detection kit. In the absence of nitric oxide both inhibitors caused relaxation, and the dilator response was increased by 2.5-fold using SP600125 in comparison with U0126. Transient endothelium-dependent contractions were blocked by U0126, whereas SP600125 strongly attenuated sustained PGF(2α)-induced contractions. U0126 inhibited only phosphorylation of ERK1/2, while SP600125 at higher concentrations not only inhibited phosphorylation of c-Jun but also ERK1/2 phosphorylation. In conclusion, the present study demonstrates that in aortae inhibition of activated ERK1/2 and JNKs mediates vascular relaxation, even in the absence of nitric oxide. Activation of ERK1/2 contributes predominantly to transient endothelium-dependent contractions while JNKs, possibly synergistically with ERK1/2, leads to sustained PGF(2α)-induced contractions.
Bhattacharya
Indranil
I
Research Unit, Division of Internal Medicine, University Hospital of Zurich, Switzerland. indranil.bhattacharya@usz.ch
Damjanović
Marlen
M
Dominguez
Ana Perez
AP
Haas
Elvira
E
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology*; D015237:Dinoprost / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D066298:In Vitro Techniques; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D009569:Nitric Oxide / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D010750:Phosphoproteins; D047428:Protein Kinase Inhibitors; D009569:Nitric Oxide; D015237:Dinoprost; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D000109:Acetylcholine