Vol.18 No.6

Original Article

Human voltage-dependent anion selective channel 1 is a target antigen for antiglomerular endothelial cell antibody in mixed connective tissue disease

Authors

Tamami Kikuchi1 , Yutaka Yoshida2 , Tetsuo Morioka1 , Fumitake Gejyo3 , Takashi Oite1

  • Department of Cellular Physiology, Institute of Nephrology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Niigata, 951-8510, Japan
  • Department of Structural Pathology, Institute of Nephrology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
  • Department of Internal Medicine II, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
Received:

25 March 2008

Accepted:

14 May 2008

Published online:

21 June 2008

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Abstract

The purpose of this study was to identify the endothelial cell antigens that react with circulating antiendothelial antibody (AECA) in mixed connective tissue disease (MCTD). We screened serum AECA reactivity in 23 patients with MCTD using a human glomerular endothelial cell (HGEC) cellular ELISA. Proteomics, twodimensional gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry were used to identify the endothelial cell antigens of HGECs that reacted with serum antibodies from MCTD patients. Sera from 12 patients (52.0%) were positive for anti-HGEC antibody based on cellular ELISA. MALDI-TOF mass spectrometry used in combination with immunoblotting using serum antibody revealed one protein spot that represented a 36-kDa cell component of HGECs, with an isoelectric point (IP) of about 9, which had a high homology with the voltage-dependent anion-selective channel 1 (VDAC-1). This protein spot was confirmed to react with the antibody specific to VDAC-1. This is the first report of the presence of antibody to VDAC-1 from HGECs in the sera from MCTD patients. Although future studies will be needed to clarify the disease specificity of the a-VDAC-1 antibody in MCTD, the results show that modern proteomics technology is useful for identifying antigens that react with AECA in autoimmune diseases such as MCTD.

Key words

Antiendothelial cell antibody - HGEC - MCTD - Proteomics - VDAC-1