Receptor-interacting protein 2 controls pulmonary host defense to Escherichia coli infection via the regulation of interleukin-17A

Infect Immun. 2011 Nov;79(11):4588-99. doi: 10.1128/IAI.05641-11. Epub 2011 Aug 15.

Abstract

Recognition of microbial patterns by host receptors is the first step in a multistep sequence leading to neutrophil-dependent host resistance. Although the role of membrane-bound sensors in bacterial recognition has been examined in detail, the importance of cytosolic sensors in the lungs is largely unexplored. In this context, there is a major lack of understanding related to the downstream signaling mediators, such as cells and/or molecules, during acute extracellular Gram-negative bacterial pneumonia. In order to determine the role of NOD-like receptors (NLRs), we used an experimental Escherichia coli infection model using mice deficient in the gene coding for the NLR adaptor, receptor-interacting protein 2 (RIP2). RIP2(-/-) mice with E. coli infection displayed higher bacterial burden and reduced neutrophil recruitment and tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), macrophage inflammatory protein 2 (MIP-2), and CXCL5/LIX expression, along with attenuated histopathological changes in the lungs. Decreased IL-17A levels were observed, along with lower numbers of IL-17A-producing T cells, in RIP2(-/-) mice after infection. RIP2(-/-) mice also show reduced IL-6 and IL-23 levels in the lungs, along with decreased activation of STAT3 after infection. Furthermore, activation of NF-κB and mitogen-activated protein kinases (MAPKs) and expression of intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) in the lungs of infected RIP2(-/-) mice were attenuated following infection. Although neutrophil mobilization to the blood was impaired in RIP2(-/-) mice following infection, the expression of CD62P, CD11a/18, CD11b, and CXCR2 on blood and lung neutrophils was not altered between infected wild-type (WT) and RIP2(-/-) mice. Thus, RIP2 contributes to neutrophil-dependent host defense against an extracellular Gram-negative pathogen via (i) IL-17A regulation and (ii) neutrophil mobilization to the blood.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, CD / genetics
  • Antigens, CD / metabolism
  • Cell Adhesion / physiology
  • Dendritic Cells / metabolism
  • Escherichia coli
  • Escherichia coli Infections / immunology*
  • Gene Expression Regulation / immunology*
  • Immunity, Mucosal
  • Inflammation / metabolism
  • Interleukin-17 / genetics
  • Interleukin-17 / metabolism*
  • Interleukin-23 / genetics
  • Interleukin-23 / metabolism
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism
  • Lung / cytology
  • Lung / microbiology
  • Lung Diseases / immunology
  • Lung Diseases / microbiology*
  • Lymphocyte Function-Associated Antigen-1 / genetics
  • Lymphocyte Function-Associated Antigen-1 / metabolism
  • Macrophages / metabolism
  • Mice
  • Mice, Knockout
  • Mitogen-Activated Protein Kinase Kinases
  • NF-kappa B / metabolism
  • Neutrophils / physiology
  • Receptor-Interacting Protein Serine-Threonine Kinase 2
  • Receptor-Interacting Protein Serine-Threonine Kinases / genetics
  • Receptor-Interacting Protein Serine-Threonine Kinases / metabolism*

Substances

  • Antigens, CD
  • Interleukin-17
  • Interleukin-23
  • Interleukin-6
  • Lymphocyte Function-Associated Antigen-1
  • NF-kappa B
  • Receptor-Interacting Protein Serine-Threonine Kinase 2
  • Receptor-Interacting Protein Serine-Threonine Kinases
  • Ripk2 protein, mouse
  • Mitogen-Activated Protein Kinase Kinases