Expression of Semaphorin 4A and its potential role in rheumatoid arthritis.
Expression of Semaphorin 4A and its potential role in rheumatoid arthritis.
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Semaphorin 4A 的表达及其在类风湿性关节炎中的潜在作用
DOI：
10.1186/s13075-015-0734-y
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发表时间：
2015-08-25
影响因子：
4.9
通讯作者：
Chang X
中科院分区：
文献类型：
--
作者：
Wang L;Song G;Zheng Y;Tan W;Pan J;Zhao Y;Chang X
Semaphorin 4A(Sema4a)在神经元发育、血管生成、免疫反应调节、自身免疫和感染性疾病等多种生理和病理过程中发挥重要作用。本研究旨在研究其在类风湿关节炎(RA)中的表达及其生物学活性。方法从类风湿关节炎(RA)和骨关节炎(OA)患者的滑膜组织中提取RNA和蛋白质。应用重组人Sema4A(RhSema4A)或小干扰RNA(SiRNA)处理RA滑膜成纤维细胞(RASF)，观察其对RASF生物学活性的影响。用定量逆转录聚合酶链式反应和Western印迹法检测脂多糖刺激后Sm a4a和NF-κB的表达。应用染色质免疫沉淀(ChIP)和靶向p50、p60的小干扰RNA检测核因子-kappaB(NF-κB)对Sima4a的调节作用。结果RA患者滑膜组织和滑液中Sema4a水平明显高于OA患者，IL-1β(IL-1β)、IL-6(IL-6)和肿瘤坏死因子-α(α)的分泌量明显高于RA患者。此外，RA患者滑液中Sema4a水平与疾病活动评分(DAS)相关。RhSema4A通过上调基质金属肽酶3(MMP3)、MMP9、α-平滑肌肌动蛋白(α-SMA)和波形蛋白的表达来促进RASF的侵袭，并通过促进RASF产生IL-6和THP-1细胞产生IL-1β和肿瘤坏死因子-α而加重炎症反应。从蛋白水平证实了Sema4a对RA患者体液中IL-6和肿瘤坏死因子-α的诱导作用。击倒实验表明，丛状蛋白B1对rhSema4A具有诱导细胞因子的作用。此外，脂多糖刺激诱导RASF中的Sema4a的表达依赖于NF-κB，而重组人Sema4A处理也可以激活NF-κB信号。此外，增加Sema4a的表达是促进RA炎症所必需的。
IntroductionSemaphorin 4A (Sema4A) plays critical roles in many physiological and pathological processes including neuronal development, angiogenesis, immune response regulation, autoimmunity, and infectious diseases. The present study aimed to investigate its expression and biological activity in rheumatoid arthritis (RA).MethodsRNA and protein were isolated from synovial tissues in RA and osteoarthritis (OA) patients. Treatment with recombinant human Sema4A (rhSema4A) or small interfering RNA (siRNA) was applied to examine its effect on the biological activity of synovial fibroblasts of RA (RASFs). Expression of Sema4A and NF-κB were measured by quantitative RT-PCR (qRT-PCR) and Western blot after lipopolysaccharide (LPS) stimulation. Chromatin immunoprecipitation (ChIP) and siRNA targeting p50 and p60 were applied to detect the regulation of Nuclear factor kappa (NF-κB) on Sema4A. Sema4A, interleukin 1β (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) secretion were measured by ELISA-based assays.ResultsIncreased levels of Sema4A were detected in the synovial tissue and fluid of patients with RA compared with those with OA. Furthermore, synovial fluid level of Sema4A correlated with Disease Activity Score (DAS) in RA. Treatment with rhSema4A promoted invasion of RASFs by upregulating the expression of Matrix metallopeptidase3 (MMP3), MMP9, alpha-smooth muscle actin(α-SMA), and Vimentin, and exacerbated inflammation by promoting the production of IL-6 in RASFs, as well as IL-1β and TNF-α in THP-1 cells. The induction of IL-6 and TNF-α by Sema4A was confirmed at the protein level in fluid samples from patients with RA. Knock-down experiments showed the participation of Plexin B1 towards rhSema4A in the induction of cytokines. In addition, LPS stimulation induced Sema4A expression in RASFs in an NF-κB-dependent manner, and rhSema4A treatment could also activate NF-κB signaling.ConclusionsThese findings suggest an NF-κB-dependent modulation of Sema4A in the immune response. Further, increased expression of Sema4A is required to promote inflammation of RA.