Up-regulation of adhesion molecule expression in glomerular endothelial cells by anti-myeloperoxidase antibody

Nephrol Dial Transplant. 2007 Jan;22(1):77-87. doi: 10.1093/ndt/gfl555. Epub 2006 Sep 27.

Abstract

Background: Anti-neutrophil cytoplasmic antibody directed against myeloperoxidase (MPO-ANCA) has been implicated in pauci-immune crescentic glomerulonephritis. It stimulates primed neutrophils to adhere to glomerular endothelial cells (GECs), thereby releasing reactive oxygen and other toxic substances and ultimately damaging the GECs. Though, a pathogenic role for MPO-ANCA is not fully understood, we hypothesized that MPO-ANCA modulates GEC functions by the increases in expression of adhesion molecules.

Methods: A polyclonal rabbit anti-recombinant mouse MPO antibody (anti-rmMPO IgG) was evaluated in mouse GEC (mGEC) for its effect on adhesion molecule expression. The primary culture of mGEC was incubated with anti-rmMPO IgG or isotype control and the expression of intercellular adhesion molecules-1 (ICAM-1) was evaluated by real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis and ICAM-1 cell ELISA.

Results: The real-time RT-PCR analysis showed that a treatment with 100 microg/ml anti-rmMPO IgG increased the expression of mRNAs for ICAM-1, vascular cell adhesion molecule-1 and E-selectin by approximately 12.5, 7.5 and 10.5-fold, respectively. ICAM-1 cell ELISA also substantiated increased expression of ICAM-1. This enhancement of ICAM-1 expression was mediated by the antigen specificity of anti-rmMPO IgG. In addition, there were several proteins in mGEC specifically immunoprecipitated with anti-rmMPO IgG.

Conclusions: These results showed that anti-MPO antibody activates not only neutrophils, but also GEC, indicating that anti-rmMPO IgG-induced direct activation of GEC contributes to neutrophil adhesion to GEC, thereby increasing glomerular neutrophil infiltration in initiation and progression of pauci-immune glomerulonephritis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies / chemistry
  • Cell Adhesion Molecules / metabolism*
  • Endothelial Cells / cytology
  • Endothelial Cells / metabolism*
  • Glomerulonephritis / metabolism
  • Immunoglobulin G / chemistry
  • Kidney Glomerulus / cytology*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neutrophils / metabolism
  • Peroxidase / chemistry
  • Peroxidase / immunology*
  • Peroxidase / metabolism
  • Rabbits
  • Reactive Oxygen Species
  • Up-Regulation*

Substances

  • Antibodies
  • Cell Adhesion Molecules
  • Immunoglobulin G
  • Reactive Oxygen Species
  • Peroxidase