RETRACTED: Blockade of TNF-α signaling suppresses the AREG-mediated IL-6 and IL-8 cytokines secretion induced by anti-Ro/SSA autoantibodies

The aim of this study was to analyze the Furin-TNF-α-converting enzyme (TACE)-amphiregulin (AREG)-IL-6/IL-8 secretion pathway in non-neoplastic human salivary gland epithelial cells (SGECs) stimulated with anti-Ro/SSA autoantibodies (Abs). We examined whether anti-Ro/SSA Abs-mediated TACE activation is responsible for AREG activation. As recent studies have demonstrated that AREG could induce proinflammatory cytokines secretion in epithelial cells, we discuss how TACE-mediated AREG shedding, caused by anti-Ro/SSA Abs treatment, could have a critical role in TNF-α-induced IL-6 and IL-8 secretion by SGEC. Furthermore, the effects of TNF-α blockade on AREG expression and TNF-α-AREG-mediated IL-6 and IL-8 secretion were evaluated. We have discovered that the upregulation of AREG occurs through TNF-α produced after anti-Ro/SSA Abs uptake via Fcγ receptors. Biological drug adalimumab and the gene silencing technique were used to study the AREG-IL-6/IL-8 secretion pathway, demonstrating that (i) adalimumab-mediated TNF-α blocking and TNF-α gene silencing provoke a significant decrease of proinflammatory cytokines production and AREG expression in anti-Ro/SSA Abs-treated SGEC; (ii) AREG gene silencing has a potent inhibitory effect on TNF-α-induced IL-6 and IL-8 secretion in SGEC treated with anti-Ro/SSA Abs; (iii) an inspection of the kinetics of cytokine production after exogeni TNF-α and AREG addition, and the use of cycloheximide in the presence of exogenous TNF-α as stimulant, clarified that TNF-α induces IL-6 and IL-8 secretion through AREG.Laboratory Investigation advance online publication, 20 September 2010; doi:10.1038/labinvest.2010.168.

Expression of pro-inflammatory TACE-TNF-α-amphiregulin axis in Sjögren's syndrome salivary glands

The tumor-necrosis-factor-converting-enzyme (TACE)-TNF-α-Amphiregulin (AREG) axis plays an important pathogenic role in inflammatory and autoimmune disorders. However, the pathological roles of these proteins in the chronic autoimmune disease Sjögren's syndrome (SS) remain to be elucidated. It is known that the TACE-AREG axis is clearly part of a larger cascade of signals that starts with the activation of Furin, responsible for maturation of TACE that, in turn, determines the production of active TNF-α, directly involved in the up-regulation of AREG expression. This study showed that Furin, TACE, TNF-α, and AREG proteins, detected in acinar and ductal cells of human salivary glands from SS patients, increased remarkably in comparison with biopsies of labial salivary glands from healthy controls. The changes in Furin, TACE, TNF- α, and AREG proteins' level detected in salivary glands biopsies of SS patients could be responsible for pro-inflammatory cytokines overexpression characterizing Sjögren's syndrome.