20-HETE increases NADPH oxidase-derived ROS production and stimulates the L-type Ca2+ channel via a PKC-dependent mechanism in cardiomyocytes.
The production of 20-hydroxyeicosatetraenoic acid (20-HETE) is increased during ischemia-reperfusion, and inhibition of 20-HETE production has been shown to reduce infarct size caused by ischemia. This study was aimed to discover the molecular mechanism underlying the action of 20-HETE in cardiac myocytes. The effect of 20-HETE on L-type Ca(2+) currents (I(Ca,L)) was examined in rat isolated cardiomyocytes by patch-clamp recording in the whole cell mode. Superfusion of cardiomyocytes with 20-HETE (10-100 nM) resulted in a concentration-dependent increase in I(Ca,L), and this action of 20-HETE was attenuated by a specific NADPH oxidase inhibitor, gp91ds-tat (5 μM), or a superoxide scavenger, polyethylene glycol-superoxide dismutase (25 U/ml), suggesting that NADPH-oxidase-derived superoxide is involved in the stimulatory action of 20-HETE on I(Ca,L). Treatment of cardiomyocytes with 20-HETE (100 nM) increased both NADPH oxidase activity and superoxide production by approximately twofold. To study the molecular mechanism mediating the 20-HETE-induced increase in NADPH oxidase activity, PKC activity was measured in cardiomyocytes. Incubation of the cells with 20-HETE (100 nM) significantly increased PKC activity, and pretreatment of cardiomyocytes with a selective PKC inhibitor, GF-109203 (1 μM), attenuated the 20-HETE-induced increases in I(Ca,L) and in NADPH oxidase activity. In summary, 20-HETE stimulates NADPH oxidase-derived superoxide production, which activates L-type Ca(2+) channels via a PKC-dependent mechanism in cardiomyocytes. 20-HETE and 20-HETE-producing enzymes could be novel targets for the treatment of cardiac ischemic diseases.
Zeng
Qinghua
Q
Laboratory of Molecular and Cellular Physiology, School of Life Sciences, Northeast Normal University, Changchun, Jilin, China. ZengQH707@gmail.com
Han
Yong
Y
Bao
Yuyan
Y
Li
Wei
W
Li
Xingting
X
Shen
Xin
X
Wang
Xu
X
Yao
Fanrong
F
O'Rourke
Stephen T
ST
Sun
Chengwen
C
D000818:Animals; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D055724:Electrophysiological Phenomena; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006893:Hydroxyeicosatetraenoic Acids / Q000494:pharmacology*; D008297:Male; D023421:Models, Animal; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D019255:NADPH Oxidases / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D013481:Superoxides / Q000378:metabolism
D020746:Calcium Channels, L-Type; D006893:Hydroxyeicosatetraenoic Acids; D017382:Reactive Oxygen Species; D013481:Superoxides; C055987:20-hydroxy-5,8,11,14-eicosatetraenoic acid; D019255:NADPH Oxidases; D011493:Protein Kinase C