Section of Cell Biology, Department of Human Anatomy and Histology, University of Bari Medical School, piazza Giulio Cesare 1, I-70124 Bari, Italy.
Int Immunol. 2009 Dec;21(12):1341-9. doi: 10.1093/intimm/dxp103. Epub 2009 Oct 23.
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.
肿瘤坏死因子 (TNF)-alpha 的可溶形式从质膜释放是通过激活 TNF-alpha 转化酶（TACE）实现的。本研究旨在研究抗 Ro/SSA 自身抗体 (Abs) 是否能够调节非肿瘤性人涎腺上皮细胞 (SGEC) 培养物中的 TACE 表达。我们研究了抗 Ro/SSA Abs 对细胞表面 TACE 的定位和丰度以及 TACE 前肽脱落和激活的影响。此外，还讨论了生物制剂阿达木单抗阻断 TNF-alpha 对 TACE 翻译后调节的潜在生理后果。使用 Sepharose 4B-Ro/SSA 亲和柱从原发性干燥综合征患者的 IgG 部分纯化抗 Ro/SSA Abs。流式细胞术、逆转录-PCR、western blot 和免疫组织化学用于研究 SGEC 上的 TACE 表达和 Abs 对 TACE 的调节。我们的研究表明，抗 Ro/SSA Abs 处理的 SGEC 中 TACE 信使 RNA (mRNA) 表达呈剂量依赖性增加，随后 TACE 蛋白内化、前肽脱落和激活，表明 TACE 活性增加是抗 Ro/SSA Abs 刺激 SGEC 中观察到的 TNF-alpha 释放所必需的。阿达木单抗治疗使 TACE mRNA 和表面 TACE 表达水平恢复到未处理的 SGEC 观察到的水平。这些数据表明，抗 Ro/SSA Abs 对 TACE 表达和细胞内分布的影响是通过 TNF-alpha 产生发挥的。
