Up-regulation of adhesion molecule expression in glomerular endothelial cells by anti-myeloperoxidase antibody.
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.
Nagao
Tomokazu
T
Chief of Biodefense Laboratory, National Institute of Infectious Diseases (NIID-NIH), Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, Japan.
Matsumura
Mimiko
M
Mabuchi
Ayako
A
Ishida-Okawara
Akiko
A
Koshio
Osamu
O
Nakayama
Toshinori
T
Minamitani
Haruyuki
H
Suzuki
Kazuo
K
D000818:Animals; D000906:Antibodies / Q000737:chemistry; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D005921:Glomerulonephritis / Q000378:metabolism; D007074:Immunoglobulin G / Q000737:chemistry; D007678:Kidney Glomerulus / Q000166:cytology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000378:metabolism; D009195:Peroxidase / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D011817:Rabbits; D017382:Reactive Oxygen Species; D015854:Up-Regulation
D000906:Antibodies; D015815:Cell Adhesion Molecules; D007074:Immunoglobulin G; D017382:Reactive Oxygen Species; D009195:Peroxidase