Gene therapy with inducible nitric oxide synthase protects against myocardial infarction via a cyclooxygenase-2-dependent mechanism.
Although the inducible isoform of NO synthase (iNOS) mediates late preconditioning (PC), it is unknown whether iNOS gene transfer can replicate the cardioprotective effects of late PC, and the role of this protein in myocardial ischemia is controversial. Thus, the cDNA for human iNOS was cloned behind the Rous sarcoma virus (RSV) promoter to create adenovirus (Ad) 5/iNOS lacking E1, E2a, and E3 regions. Intramyocardial injection of Ad5/iNOS in mice increased local iNOS protein expression and activity and markedly reduced infarct size. The infarct-sparing effects of Ad5/iNOS were at least as powerful as those of ischemic PC. The increased iNOS expression was associated with increased cyclooxygenase-2 (COX-2) protein expression and prostanoid levels. Pretreatment with the COX-2-selective inhibitor NS-398 completely abrogated the infarct-sparing actions of Ad5/iNOS, demonstrating that COX-2 is an obligatory downstream effector of iNOS-dependent cardioprotection. We conclude that gene transfer of iNOS (an enzyme commonly thought to be detrimental) affords powerful cardioprotection the magnitude of which is equivalent to that of late PC. This is the first report that upregulation of iNOS, in itself, is sufficient to reduce infarct size. The results provide proof-of-principle for gene therapy against ischemia/reperfusion injury, which increases local myocardial NO synthase levels without the need for continuous intravenous infusion of NO donors and without altering systemic hemodynamics. The data also reveal the existence of a close coupling between iNOS and COX-2, whereby induction of the former enzyme leads to secondary induction of the latter, which in turn mediates the cytoprotective effects of iNOS. We propose that iNOS and COX-2 form a stress-responsive functional module that mitigates ischemia/reperfusion injury.
Li
Qianhong
Q
Division of Cardiology, University of Louisville, the Jewish Hospital Heart and Lung Institute, Louisville, KY 40292, USA.
Guo
Yiru
Y
Xuan
Yu-Ting
YT
Lowenstein
Charles J
CJ
Stevenson
Susan C
SC
Prabhu
Sumanth D
SD
Wu
Wen-Jian
WJ
Zhu
Yanqing
Y
Bolli
Roberto
R
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D051546:Cyclooxygenase 2; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D007763:Lac Operon / Q000235:genetics; D008565:Membrane Proteins; D051379:Mice; D008813:Mice, Inbred ICR; D009203:Myocardial Infarction / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D019001:Nitric Oxide Synthase / Q000235:genetics* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D011453:Prostaglandins / Q000378:metabolism; D013997:Time Factors; D016896:Treatment Outcome
D007527:Isoenzymes; D008565:Membrane Proteins; D011453:Prostaglandins; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases