Induction of VEGF and MMP-9 expression by toll-like receptor 2/4 in human endothelial cells infected with Chlamydia pneumoniae

Int J Immunopathol Pharmacol. 2012 Apr-Jun;25(2):377-86. doi: 10.1177/039463201202500207.

Abstract

Matrix metalloproteinases (MMP) are a family of host-derived enzymes involved in the turnover of extracellular matrix (ECM) molecules, and, in particular, it is demonstrated that the 92 KDa gelatinase MMP-9 is often expressed in atherosclerotic plaques by macrophages and smooth muscle cells. Recent evidence supports a role of Toll-like receptor (TLR) signaling in the development of atherosclerosis lesions. In this study, we analyzed the TLR2/TLR4 expression in HUVEC infected with C. pneumoniae and correlated it to the production of VEGF and MMP-9. The results obtained showed an increased VEGF and MMP-9 production correlated with a time-dependent increase in cellular proliferation in HUVEC infected with C. pneumoniae at a multiplicity of infection (MOI) of 2 IFU/cell. HUVEC preincubated with VEGF antibody did not release MMP-9, as detected by zymography assessment and ELISA assay. In addition, we demonstrated that TLR2/TLR4 are expressed in HUVEC infected with viable microorganisms (25% and 17%, respectively), while UV-inactivated microorganisms induced a lesser expression (20% and 11%, respectively) compared to control cells and HUVEC exposed to heat-killed bacteria showed a percentage of TLR-expressing cells similar to the control cells. In addition, the cells preincubated for 60 min with TLR2/TLR4 neutralizing antibodies showed a decrease in C. pneumonia-induced VEGF and MMP-9 production.

MeSH terms

  • Antibodies, Neutralizing
  • Cell Proliferation
  • Cells, Cultured
  • Chlamydophila pneumoniae / growth & development
  • Chlamydophila pneumoniae / immunology
  • Chlamydophila pneumoniae / pathogenicity*
  • Chlamydophila pneumoniae / radiation effects
  • Enzyme-Linked Immunosorbent Assay
  • Human Umbilical Vein Endothelial Cells / enzymology
  • Human Umbilical Vein Endothelial Cells / immunology
  • Human Umbilical Vein Endothelial Cells / microbiology*
  • Humans
  • Matrix Metalloproteinase 9 / metabolism*
  • Time Factors
  • Toll-Like Receptor 2 / immunology
  • Toll-Like Receptor 2 / metabolism*
  • Toll-Like Receptor 4 / immunology
  • Toll-Like Receptor 4 / metabolism*
  • Ultraviolet Rays
  • Up-Regulation
  • Vascular Endothelial Growth Factor A / metabolism*

Substances

  • Antibodies, Neutralizing
  • TLR2 protein, human
  • TLR4 protein, human
  • Toll-Like Receptor 2
  • Toll-Like Receptor 4
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Matrix Metalloproteinase 9