Obligatory Role of Intraluminal O2− in Acute Endothelin-1 and Angiotensin II Signaling to Mediate Endothelial Dysfunction and MAPK Activation in Guinea-Pig Hearts

International Journal of Molecular Sciences

Emilia Wojtera²  Anna Konior²  Natalia Fedoryszak-Kuśka²  Andrzej Beręsewicz¹ 

[1]Department of Clinical Physiology, Postgraduate Medical School, Warsaw 01-813, Poland

关键词: oxidative stress;    endothelin-1;    angiotensin-II;    endothelial dysfunction;    mitogen-activated protein kinases;    mitochondria;    NADPH-oxidase;    xanthine oxidase;    guinea-pig heart;   

DOI  :  10.3390/ijms151119417

来源: mdpi

【 摘 要 】

We hypothesized that, due to a cross-talk between cytoplasmic O₂⁻-sources and intraluminally expressed xanthine oxidase (XO), intraluminal O₂⁻ is instrumental in mediating intraluminal (endothelial dysfunction) and cytosolic (p38 and ERK1/2 MAPKs phosphorylation) manifestations of vascular oxidative stress induced by endothelin-1 (ET-1) and angiotensin II (AT-II). Isolated guinea-pig hearts were subjected to 10-min agonist perfusion causing a burst of an intraluminal O₂⁻. ET-1 antagonist, tezosentan, attenuated AT-II-mediated O₂⁻, indicating its partial ET-1 mediation. ET-1 and Ang-T (AT-II + tezosentan) triggered intraluminal O₂⁻, endothelial dysfunction, MAPKs and p47phox phosphorylation, and NADPH oxidase (Nox) and XO activation. These effects were: (i) prevented by blocking PKC (chelerythrine), Nox (apocynin), mitochondrial ATP-dependent K⁺ channel (5-HD), complex II (TTFA), and XO (allopurinol); (ii) mimicked by the activation of Nox (NADH); and mitochondria (diazoxide, 3-NPA) and (iii) the effects by NADH were prevented by 5-HD, TTFA and chelerythrine, and those by diazoxide and 3-NPA by apocynin and chelerythrine, suggesting that the agonists coactivate Nox and mitochondria, which further amplify their activity via PKC. The effects by ET-1, Ang-T, NADH, diazoxide, and 3-NPA were opposed by blocking intraluminal O₂⁻ (SOD) and XO, and were mimicked by XO activation (hypoxanthine). Apocynin, TTFA, chelerythrine, and SOD opposed the effects by hypoxanthine. In conclusion, oxidative stress by agonists involves cellular inside-out and outside-in signaling in which Nox-mitochondria-PKC system and XO mutually maintain their activities via the intraluminal O₂⁻.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.