Global gene expression patterns and induction of innate immune response in human laryngeal epithelial cells in response to Acinetobacter baumannii outer membrane protein A

FEMS Immunol Med Microbiol. 2008 Oct;54(1):45-52. doi: 10.1111/j.1574-695X.2008.00446.x. Epub 2008 Jul 9.

Abstract

The outer membrane protein A of Acinetobacter baumannii (AbOmpA) is an important pathogen-associated molecular pattern that induces host cell death. We determined the gene expression profiles of human laryngeal epithelial HEp-2 cells in response to the sublethal concentration of recombinant AbOmpA (rAbOmpA) and investigated the molecular mechanisms by which rAbOmpA induces an innate immune response. The microarray analysis showed that rAbOmpA sequentially regulated a relatively small set of genes, including those associated with signal transductions and molecules involved in immune response. Among the differentially expressed genes involved in innate immune responses, the surface expression of Toll-like receptor 2 and the production of inducible nitric oxide synthase (iNOS) were prominently observed. However, rAbOmpA did not induce the production of proinflammatory cytokines and chemokines. rAbOmpA activated c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase mitogen-activated protein kinases (MAPKs). Inhibition of JNK MAPK suppressed iNOS production in the rAbOmpA-treated HEp-2 cells. These results suggest that interaction of laryngeal epithelial cells with AbOmpA has a significant impact on the induction of innate immunity during the early stages of A. baumannii infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acinetobacter baumannii / immunology*
  • Acinetobacter baumannii / metabolism
  • Bacterial Outer Membrane Proteins / genetics
  • Bacterial Outer Membrane Proteins / immunology*
  • Bacterial Outer Membrane Proteins / metabolism
  • Cell Line
  • Cytokines / genetics
  • Cytokines / metabolism
  • Epithelial Cells / immunology*
  • Gene Expression Profiling*
  • Gene Expression Regulation
  • Humans
  • Immunity, Innate / immunology*
  • Larynx / cytology
  • Larynx / immunology*
  • Nitric Oxide Synthase Type II / genetics
  • Nitric Oxide Synthase Type II / metabolism
  • Oligonucleotide Array Sequence Analysis
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology
  • Recombinant Proteins / metabolism
  • Toll-Like Receptor 2 / genetics
  • Toll-Like Receptor 2 / metabolism

Substances

  • Bacterial Outer Membrane Proteins
  • Cytokines
  • Recombinant Proteins
  • Toll-Like Receptor 2
  • OMPA outer membrane proteins
  • Nitric Oxide Synthase Type II