trans-Arachidonic acids induce a heme oxygenase-dependent vasorelaxation of cerebral microvasculature
| Autor: | Amna Kooli, Phyllis A. Dennery, Xin Hou, Elsa Kermorvant-Duchemin, Kavita Jain, Daya R. Varma, Sophie Tremblay, Florian Sennlaub, Michael Balazy, Pierre Lachapelle, Jean-Claude Honoré, Pierre Hardy, Michela Bossolasco, Tang Zhu, Sylvain Chemtob, Przemyslaw Sapieha |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Potassium Channels
Endothelium Arachidonic Acids Pharmacology Biochemistry Nitric oxide Immunoenzyme Techniques Rats Sprague-Dawley chemistry.chemical_compound Lipoxygenase Physiology (medical) Cyclic AMP medicine Animals Immunoprecipitation RNA Messenger Large-Conductance Calcium-Activated Potassium Channel alpha Subunits Cyclic GMP Cells Cultured Nitrites biology Reverse Transcriptase Polymerase Chain Reaction Chemistry Activator (genetics) Bilirubin Stereoisomerism Iberiotoxin Potassium channel Rats Vasodilation Heme oxygenase medicine.anatomical_structure Cerebrovascular Circulation Heme Oxygenase (Decyclizing) biology.protein Arachidonic acid Endothelium Vascular |
| Zdroj: | Free Radical Biology and Medicine. 44:815-825 |
| ISSN: | 0891-5849 |
| DOI: | 10.1016/j.freeradbiomed.2007.11.006 |
| Popis: | Nitrative stress is an important regulator of vascular tone. We have recently described that trans-arachidonic acids (TAA) are major products of NO(2)(.)-mediated isomerization of arachidonic acid in cell membranes and that nitrative stress increases TAA levels leading to neural microvascular degeneration. In the present study, we explored whether TAA exert acute effects on neuromicrovascular tone and investigated potential mechanisms thereof. TAA induced an endothelium-dependent vasorelaxation of rat brain pial microvasculature. This vasorelaxation was independent of nitric oxide, prostanoids, lipoxygenase products, and CYP(450) metabolite trans-hydroxyeicosatetraenoic acids. However, inhibition of heme oxygenase (using zinc protoporphyrin IX) and of dependent soluble guanylate cyclase (sGC; using ODQ) significantly diminished (by approximately 70%) the TAA-induced vasorelaxation. Consistent with these findings, TAA stimulated heme oxygenase (HO)-2-dependent bilirubin (using siRNA HO-2) and cGMP formation, and the HO product carbon monoxide (using CO-releasing CORM-2) reproduced the sGC-dependent cGMP formation and vasorelaxation. Further exploration revealed that TAA-induced vasorelaxation and bilirubin formation (HO activation) were nearly abrogated by large-conductance calcium-dependent potassium channels (BK(Ca)) (using TEA and iberiotoxin). Opening of BK(Ca) with the selective activator NS1619 induced a concentration-dependent vasorelaxation, which was inhibited by HO and sGC inhibitors. Coimmunoprecipitation suggested a molecular complex interaction between BK(Ca) and HO-2 (but not HO-1). Collectively, these findings identify new properties of TAA, specifically cerebral vasorelaxation through interactive activation of BK(Ca) with HO-2 and, in turn, sGC. Our findings provide new insights into the characterization of nitrative stress-derived TAA products, by showing they can act as acute mediators of nitrative stress on neurovascular tone. |
| Databáze: | OpenAIRE |
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