Cao Z, Ren D, Ha T, Liu L, Wang X, Kalbfleisch J, Gao X, Kao R, Williams D, Li C. CpG-ODN, the TLR9 agonist, attenuates myocardial ischemia/reperfusion injury: involving activation of PI3K/Akt signaling.
Biochim Biophys Acta Mol Basis Dis 2012;
1832:96-104. [PMID:
22917564 DOI:
10.1016/j.bbadis.2012.08.008]
[Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 07/31/2012] [Accepted: 08/08/2012] [Indexed: 01/04/2023]
Abstract
BACKGROUND
Toll-like receptors (TLRs) have been implicated in myocardial ischemia/reperfusion (I/R) injury. The TLR9 ligand, CpG-ODN has been reported to improve cell survival. We examined effect of CpG-ODN on myocardial I/R injury.
METHODS
Male C57BL/6 mice were treated with either CpG-ODN, control-ODN, or inhibitory CpG-ODN (iCpG-ODN) 1h prior to myocardial ischemia (60min) followed by reperfusion. Untreated mice served as I/R control (n=10/each group). Infarct size was determined by TTC straining. Cardiac function was examined by echocardiography before and after myocardial I/R up to 14days.
RESULTS
CpG-ODN administration significantly decreased infarct size by 31.4% and improved cardiac function after myocardial I/R up to 14days. Neither control-ODN nor iCpG-ODN altered I/R-induced myocardial infarction and cardiac dysfunction. CpG-ODN attenuated I/R-induced myocardial apoptosis and prevented I/R-induced decrease in Bcl2 and increase in Bax levels in the myocardium. CpG-ODN increased Akt and GSK-3β phosphorylation in the myocardium. In vitro data suggested that CpG-ODN treatment induced TLR9 tyrosine phosphorylation and promoted an association between TLR9 and the p85 subunit of PI3K. Importantly, PI3K/Akt inhibition and Akt kinase deficiency abolished CpG-ODN-induced cardioprotection.
CONCLUSION
CpG-ODN, the TLR9 ligand, induces protection against myocardial I/R injury. The mechanisms involve activation of the PI3K/Akt signaling pathway.
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