Induction of TNF-alpha-converting enzyme-ectodomain shedding by pathogenic autoantibodies.
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.
Section of Cell Biology, Department of Human Anatomy and Histology, University of Bari Medical School, piazza Giulio Cesare 1, I-70124 Bari, Italy. m.sisto@anatomia.uniba.it
Margherita
M
Sisto
Sabrina
S
Lisi
Dario Domenico
DD
Lofrumento
Maria Antonia
MA
Frassanito
Liana
L
Cucci
Simona
S
D'Amore
Vincenzo
V
Mitolo
Massimo
M
D'Amore
D051722:ADAM Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D000072198:ADAM17 Protein; D000068879:Adalimumab; D000974:Antibodies, Antinuclear / Q000276:immunology* / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000494:pharmacology; D061067:Antibodies, Monoclonal, Humanized; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D012469:Salivary Glands / Q000166:cytology* / Q000187:drug effects / Q000276:immunology; D012859:Sjogren's Syndrome / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D000974:Antibodies, Antinuclear; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; C035356:SS-A antibodies; D014409:Tumor Necrosis Factor-alpha; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; D000068879:Adalimumab