Pan Fang, Zhu Lihua, Lv Haozhe, Pei Chunpeng
Department of Rheumatology, Daqing Oilfield General Hospital, Daqing, Heilongjiang, P.R. China.
Department of Renal Diseases, The First Affiliated Hospital, Heilongjiang University of Chinese Medicine, Harbin, Heilongjiang, P.R. China.
Int J Mol Med. 2016 Nov;38(5):1507-1514. doi: 10.3892/ijmm.2016.2755. Epub 2016 Sep 28.
Rheumatoid arthritis (RA) is a chronic autoimmune joint disease and fibroblast-like synoviocytes (FLS) are the resident mesenchymal cells of synovial joints. Quercetin is a dietary antioxidant. In this study, we aimed to explore the mechanisms responsible for the quercetin-induced apoptosis of FLS from patients with RA (termed RAFLS). RAFLS viability was determined following treatent of the cells with or without quercetin using the Cell Counting kit-8 (CCK-8) assay. The apoptosis of the RAFLS was analyzed using the Annexin V-fluorescein isothiocyanate (FITC) apoptosis detection kit I. The results revealed that RAFLS viability decreased and apoptosis increased in following treatment with quercetin. The differentially expressed long non-coding RNAs (lncRNAs) were screened and marked by PCR array following treatment with quercetin. The expression levels of the screened lncRNAs were then determined and compared in the cells treated with or without quercetin by quantitative PCR. The lncRNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) was finally selected. Small interfering RNA (siRNA) was then used to knock down the expression of MALAT1 in order to determine the role of MALAT1 in the quercetin-induced apoptosis of RAFLS. The results revealed that the knockdown of MALAT1 inhibited RAFLS apoptosis. At the same time, the expression of caspase-3 and caspase-9 was significantly decreased in the cells in which MALAT1 was knocked down. The phosphoinositide 3-kinase (PI3K)/AKT signaling pathway was activated; this activation is known to be associated with enhanced cell proliferation and decreased apoptosis. The findings of our study indicate that quercetin promotes RAFLS apoptosis by upregulating lncRNA MALAT1, and that MALAT1 induces apoptosis by inhibiting the activation of the PI3K/AKT pathway.
类风湿关节炎（RA）是一种慢性自身免疫性关节疾病，成纤维样滑膜细胞（FLS）是滑膜关节中的常驻间充质细胞。槲皮素是一种膳食抗氧化剂。在本研究中，我们旨在探究槲皮素诱导类风湿关节炎患者FLS（称为RAFLS）凋亡的机制。使用细胞计数试剂盒-8（CCK-8）检测法，在有或无槲皮素处理细胞后，测定RAFLS的活力。使用膜联蛋白V-异硫氰酸荧光素（FITC）凋亡检测试剂盒I分析RAFLS的凋亡情况。结果显示，用槲皮素处理后，RAFLS活力降低，凋亡增加。在用槲皮素处理后，通过PCR芯片筛选并标记差异表达的长链非编码RNA（lncRNA）。然后通过定量PCR测定并比较在有或无槲皮素处理的细胞中筛选出的lncRNA的表达水平。最终选择了lncRNA转移相关肺腺癌转录本1（MALAT1）。然后使用小干扰RNA（siRNA）敲低MALAT1的表达，以确定MALAT在槲皮素诱导RAFLS凋亡中的作用。结果显示，敲低MALAT1可抑制RAFLS凋亡。同时，在敲低MALAT1的细胞中，半胱天冬酶-3和半胱天冬酶-9的表达显著降低。磷酸肌醇3-激酶（PI3K）/AKT信号通路被激活；已知这种激活与增强细胞增殖和降低凋亡有关。我们的研究结果表明，槲皮素通过上调lncRNA MALAT1促进RAFLS凋亡，且MALAT1通过抑制PI3K/AKT途径的激活诱导凋亡。
