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Biochim Biophys Acta. 2014 May;1842(5):701-11. doi: 10.1016/j.bbadis.2014.01.012. Epub 2014 Jan 29.

Loss of duplexmiR-223 (5p and 3p) aggravates myocardial depression and mortality in polymicrobial sepsis.

Author information

1
Department of Pharmacology and Cell Biophysics.
2
Department of Pathology and Laboratory Medicine.
3
Critical Illness Research, Lawson Health Research Institute, Ontario N6A 4G5, Canada.
4
Institute of Biosciences and Technology, Texas A&M Health Science Center, TX, USA.
5
Department of Surgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
6
Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
7
Department of Pharmacology and Cell Biophysics. Electronic address: fangg@ucmail.uc.edu.

Abstract

Sepsis is the leading cause of death in critically ill patients. While myocardial dysfunction has been recognized as a major manifestation in severe sepsis, the underlying molecular mechanisms associated with septic cardiomyopathy remain unclear. In this study, we performed a miRNA array analysis in hearts collected from a severe septic mouse model induced by cecal ligation and puncture (CLP). Among the 19 miRNAs that were dys-regulated in CLP-mouse hearts, miR-223(3p) and miR-223*(5p) were most significantly downregulated, compared with sham-operated mouse hearts. To test whether a drop of miR-223 duplex plays any roles in sepsis-induced cardiac dysfunction and inflammation, a knockout (KO) mouse model with a deletion of the miR-223 gene locus and wild-type (WT) mice were subjected to CLP or sham surgery. We observed that sepsis-induced cardiac dysfunction, inflammatory response and mortality were remarkably aggravated in CLP-treated KO mice, compared with control WTs. Using Western-blotting and luciferase reporter assays, we identified Sema3A, an activator of cytokine storm and a neural chemorepellent for sympathetic axons, as an authentic target of miR-223* in the myocardium. In addition, we validated that miR-223 negatively regulated the expression of STAT-3 and IL-6 in mouse hearts. Furthermore, injection of Sema3A protein into WT mice revealed an exacerbation of sepsis-triggered inflammatory response and myocardial depression, compared with control IgG1 protein-treated WT mice following CLP surgery. Taken together, these data indicate that loss of miR-223/-223* causes an aggravation of sepsis-induced inflammation, myocardial dysfunction and mortality. Our study uncovers a previously unrecognized mechanism underlying septic cardiomyopathy and thereby, may provide a new strategy to treat sepsis.

KEYWORDS:

Inflammation; MicroRNA; Myocardial depression; Sema3A; Sepsis

PMID:
24486439
PMCID:
PMC3959587
DOI:
10.1016/j.bbadis.2014.01.012
[Indexed for MEDLINE]
Free PMC Article

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