Cellular Physiology and Biochemistry (Jun 2018)

Cpg-ODN, a TLR9 Agonist, Aggravates Myocardial Ischemia/Reperfusion Injury by Activation of TLR9-P38 MAPK Signaling

  • Liang Xie,
  • Songqing He,
  • Na Kong,
  • Ying Zhu,
  • Yi Tang,
  • Jianhua Li,
  • Zhengbing Liu,
  • Jing Liu,
  • Jianbin Gong

DOI
https://doi.org/10.1159/000490828
Journal volume & issue
Vol. 47, no. 4
pp. 1389 – 1398

Abstract

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Background/Aims: Toll-like receptors (TLRs) have been implicated in myocardial ischemia/ reperfusion (I/R) injury. We examined the effect of CpG-oligodeoxynucleotide (ODN) on myocardial I/R injury. Methods: Male Sprague-Dawley rats were treated with either CpG-ODN or control ODN 1 h prior to myocardial ischemia (30 min) followed by reperfusion. Rats treated with phosphate-buffered saline (PBS) served as I/R controls (n = 8/group). Infarct size was determined by 2,3,5-triphenyltetrazolium chloride and Evans blue straining. Cardiac function was examined by echocardiography before and up to 14 days after myocardial I/R. Results: CpG-ODN administration significantly increased infarct size and reduced cardiac function and survival rate after myocardial I/R, compared to the PBS-treated I/R group. Control-ODN did not alter I/R-induced myocardial infarct size, cardiac dysfunction, and survival rate. Additionally, CpG-ODN promoted I/R-induced myocardial apoptosis and cleaved caspase-3 levels in the myocardium. CpG-ODN increased TLR9 activation and p38 phosphorylation in the myocardium. In vitro data also suggested that CpG-ODN treatment induced TLR9 activation and p38 phosphorylation. Importantly, p38 mitogen-activated protein kinase (MAPK) inhibition abolished CpG-ODN-induced cardiac injury. Conclusion: CpG-ODN, the TLR9 ligand, accelerates myocardial I/R injury. The mechanisms involve activation of the TLR9-p38 MAPK signaling pathway.

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