Lee Tai-Ping, Leu Shr-Jeng Jim, Huang Jason C, Song Ying-Chyi, Jhou Ren-Shiang, Tang Shye-Jye, Sun Kuang-Hui
Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan, China.
Immunology. 2009 May;127(1):91-102. doi: 10.1111/j.1365-2567.2008.02925.x.
Anti-ribosomal phosphoprotein autoantibodies have been shown to be significantly associated with multiple manifestations of systemic lupus erythematosus (SLE). High levels of interleukin-10 (IL-10) have been demonstrated to contribute to lupus susceptibility and severity. In this study, we investigated the molecular mechanisms of anti-ribosomal phosphoprotein monoclonal antibody (anti-P mAb)-induced autoimmune responses. Anti-P mAb promoted IL-10 overproduction in a dose- and time-dependent manner in both lipopolysaccharide (LPS)-activated RAW 264.7 cells and primary human macrophages. Anti-P mAb enhanced phosphorylation of Akt (PKB; protein kinase B), extracellular signal regulated kinase 1/2 (ERK1/2) and c-Jun NH2-terminal kinase 1/2 (JNK1/2), while phosphorylation of p38 remained unaltered. Furthermore, anti-P mAb decreased glycogen synthase kinase 3 (GSK3) activity and reduced the phosphorylation of I kappaB alpha in LPS-activated macrophages. The Syk, phosphatidylinositol 3-kinase (PI3K), protein kinase C (PKC), JNK and ERK signalling pathways involved in anti-P mAb-triggered IL-10 secretion were also confirmed using various pharmacological inhibitors. In addition, nuclear factor (NF)-kappaB had negative regulatory effects on anti-P mAb-triggered IL-10 secretion. Using reporter plasmids containing the nuclear factor binding sites of NF-kappaB, cAMP-enhanced activation protein 1 (AP-1), serum response element (SRE) or cyclic AMP response element (CRE), treatment of anti-P mAb led to activation of the corresponding factors that bind to the AP-1 site, SRE and CRE in the LPS-activated macrophages. Furthermore, by transfection with reporter plasmids bearing various lengths of the IL-10 promoter, the AP-1 binding site, SRE and CRE were shown to be required for anti-P mAb-induced effects. Collectively, our results provide a molecular model for anti-P mAb-induced IL-10 overproduction in LPS-activated macrophages, which may play a role in the pathogenesis of SLE.
抗核糖体磷酸蛋白自身抗体已被证明与系统性红斑狼疮（SLE）的多种表现显著相关。高水平的白细胞介素10（IL-10）已被证实会导致狼疮易感性和严重程度增加。在本研究中，我们调查了抗核糖体磷酸蛋白单克隆抗体（抗-P mAb）诱导自身免疫反应的分子机制。抗-P mAb在脂多糖（LPS）激活的RAW 264.7细胞和原代人巨噬细胞中均以剂量和时间依赖性方式促进IL-10过量产生。抗-P mAb增强了Akt（蛋白激酶B；PKB）、细胞外信号调节激酶1/2（ERK1/2）和c-Jun氨基末端激酶1/2（JNK1/2）的磷酸化，而p38的磷酸化保持不变。此外，抗-P mAb降低了糖原合酶激酶3（GSK3）的活性，并减少了LPS激活的巨噬细胞中IκBα的磷酸化。使用各种药理学抑制剂也证实了参与抗-P mAb触发的IL-10分泌的Syk、磷脂酰肌醇3激酶（PI3K）、蛋白激酶C（PKC）、JNK和ERK信号通路。此外，核因子（NF）-κB对抗-P mAb触发的IL-10分泌具有负调节作用。使用含有NF-κB、cAMP增强激活蛋白1（AP-1）、血清反应元件（SRE）或环磷酸腺苷反应元件（CRE）核因子结合位点的报告质粒，抗-P mAb处理导致LPS激活的巨噬细胞中与AP-1位点、SRE和CRE结合的相应因子激活。此外，通过用携带不同长度IL-10启动子的报告质粒转染，AP-1结合位点、SRE和CRE被证明是抗-P mAb诱导效应所必需的。总体而言，我们的结果为抗-P mAb在LPS激活的巨噬细胞中诱导IL-10过量产生提供了一个分子模型，这可能在SLE的发病机制中起作用。
