NDT Advance Access originally published online on September 27, 2006
Nephrology Dialysis Transplantation 2007 22(1):77-87; doi:10.1093/ndt/gfl555
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Up-regulation of adhesion molecule expression in glomerular endothelial cells by anti-myeloperoxidase antibody
1Department of Bioactive Molecules, National Institute of Infectious Diseases, Tokyo, Japan, 2Graduate School of Science and Technology, Keio University, Yokohama, Japan, 3Department of Physiology, University of Otago, Dunedin, New Zealand, 4Department of Medicine, Teikyo University, Tokyo, Japan and 5Graduate School of Medicine, Chiba University, Chiba, Japan.
Correspondence and offprint requests to: Kazuo Suzuki PhD, Chief of Biodefense Laboratory, National Institute of Infectious Diseases (NIID-NIH), Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, Japan. Email: ksuzuki{at}nih.go.jp
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Abstract |
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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 µg/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.
Keywords: adhesion molecules; crescentic glomerulonephritis; glomerular endothelial cells; MPO-ANCA