NOD1 activation induces cardiac dysfunction and modulates cardiac fibrosis and cardiomyocyte apoptosis

PLoS One. 2012;7(9):e45260. doi: 10.1371/journal.pone.0045260. Epub 2012 Sep 18.

Abstract

The innate immune system is responsible for the initial response of an organism to potentially harmful stressors, pathogens or tissue injury, and accordingly plays an essential role in the pathogenesis of many inflammatory processes, including some cardiovascular diseases. Toll like receptors (TLR) and nucleotide-binding oligomerization domain-like receptors (NLRs) are pattern recognition receptors that play an important role in the induction of innate immune and inflammatory responses. There is a line of evidence supporting that activation of TLRs contributes to the development and progression of cardiovascular diseases but less is known regarding the role of NLRs. Here we demonstrate the presence of the NLR member NOD1 (nucleotide-binding oligomerization domain containing 1) in the murine heart. Activation of NOD1 with the specific agonist C12-iEDAP, but not with the inactive analogue iE-Lys, induces a time- and dose-dependent cardiac dysfunction that occurs concomitantly with cardiac fibrosis and apoptosis. The administration of iEDAP promotes the activation of the NF-κB and TGF-β pathways and induces apoptosis in whole hearts. At the cellular level, both native cardiomyocytes and cardiac fibroblasts expressed NOD1. The NLR activation in cardiomyocytes was associated with NF-κB activation and induction of apoptosis. NOD1 stimulation in fibroblasts was linked to NF-κB activation and to increased expression of pro-fibrotic mediators. The down-regulation of NOD1 by specific siRNAs blunted the effect of iEDAP on the pro-fibrotic TGF-β pathway and cell apoptosis. In conclusion, our report uncovers a new pro-inflammatory target that is expressed in the heart, NOD1. The specific activation of this NLR induces cardiac dysfunction and modulates cardiac fibrosis and cardiomyocyte apoptosis, pathological processes involved in several cardiac diseases such as heart failure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Biological Factors / pharmacology*
  • Dose-Response Relationship, Drug
  • Endomyocardial Fibrosis / chemically induced
  • Endomyocardial Fibrosis / complications
  • Endomyocardial Fibrosis / metabolism*
  • Endomyocardial Fibrosis / pathology
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Fibroblasts / pathology
  • Gene Expression Regulation / drug effects
  • Heart Failure / chemically induced
  • Heart Failure / complications
  • Heart Failure / metabolism*
  • Heart Failure / pathology
  • Mice
  • Myocardium / metabolism*
  • Myocardium / pathology*
  • Myocytes, Cardiac / drug effects
  • Myocytes, Cardiac / metabolism*
  • Myocytes, Cardiac / pathology
  • NF-kappa B / genetics
  • NF-kappa B / metabolism
  • Nod1 Signaling Adaptor Protein / agonists*
  • Nod1 Signaling Adaptor Protein / antagonists & inhibitors
  • Nod1 Signaling Adaptor Protein / genetics
  • RNA, Small Interfering / genetics
  • Rats
  • Signal Transduction / drug effects
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / metabolism

Substances

  • Biological Factors
  • NF-kappa B
  • Nod1 Signaling Adaptor Protein
  • Nod1 protein, mouse
  • RNA, Small Interfering
  • Transforming Growth Factor beta

Grants and funding

María Fernandez Velasco was supported by instituto de Sanidad Carlos III (Miguel Servet Program, CP11/00080). This work was supported by grants BFU2011-24760 and SAF2010-16377 from the Ministerio de Innovacion y Ciencia and Fondo de Investigacion Sanitario-Red Cardiovascular (FIS-RECAVA RD06/0014/0006 and RD06/0014/0007). The Red de Cardiovascular and Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas networks are funded by the Instituto Carlos III. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.