Induction of TNF-alpha-converting enzyme-ectodomain shedding by pathogenic autoantibodies

Int Immunol. 2009 Dec;21(12):1341-9. doi: 10.1093/intimm/dxp103. Epub 2009 Oct 23.

Abstract

The release of the soluble form of tumor necrosis factor (TNF)-alpha from the plasma membrane occurs through the activation of the secretase tumor necrosis factor-alpha-converting enzyme (TACE). The current study was designed to examine whether the anti-Ro/SSA autoantibodies (Abs) are capable to regulate TACE expression in non-neoplastic human salivary gland epithelial cells (SGEC) cultures. We investigated the effect of anti-Ro/SSA Abs on the localization and abundance of cell-surface TACE and on TACE pro-domain-shedding and activation. In addition, the potential physiological consequences of TNF-alpha blockage by the biological agent Adalimumab on post-translational regulation of TACE are discussed. Anti-Ro/SSA Abs were purified from IgG fractions of patients with primary Sjögren's syndrome, using Sepharose 4B-Ro/SSA affinity columns. Flow cytometry, reverse transcription-PCR, western blot and immunohistochemistry were used to study TACE expression on SGEC and TACE regulation by Abs. Our study demonstrated a dose-dependent increase of TACE messenger RNA (mRNA) expression in anti-Ro/SSA Abs-treated SGEC, followed by internalization, pro-domain shedding and activation of TACE protein, suggesting that increased TACE activity is necessary for the release of TNF-alpha observed in anti-Ro/SSA Abs-stimulated SGEC. Adalimumab treatment brought TACE mRNA and surface TACE expression to levels than those observed in untreated SGEC. These data suggest that the effect of anti-Ro/SSA Abs on TACE expression and intracellular distribution is exerted by TNF-alpha production.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADAM Proteins* / antagonists & inhibitors
  • ADAM Proteins* / metabolism
  • ADAM17 Protein
  • Adalimumab
  • Antibodies, Antinuclear / immunology*
  • Antibodies, Antinuclear / pharmacology
  • Antibodies, Monoclonal / immunology*
  • Antibodies, Monoclonal / pharmacology
  • Antibodies, Monoclonal, Humanized
  • Cells, Cultured
  • Epithelial Cells / cytology
  • Epithelial Cells / drug effects
  • Epithelial Cells / immunology
  • Epithelial Cells / metabolism*
  • Gene Expression / drug effects
  • Humans
  • Salivary Glands / cytology*
  • Salivary Glands / drug effects
  • Salivary Glands / immunology
  • Sjogren's Syndrome / immunology
  • Tumor Necrosis Factor-alpha / metabolism*

Substances

  • Antibodies, Antinuclear
  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • SS-A antibodies
  • Tumor Necrosis Factor-alpha
  • ADAM Proteins
  • ADAM17 Protein
  • ADAM17 protein, human
  • Adalimumab