PDF(Pubmed)
Abstract：
(1) Background: Synovial fluid (SF) from knee joints with osteoarthritis (OA) has increased levels of phospholipids (PL). We have reported earlier that TGF-ß and IGF-1 stimulate fibroblast-like synoviocytes (FLS) to synthesize increased amounts of PLs. The current study examined whether IL-1ß induces the release of PLs in FLS and the underlying mechanism. (2) Methods: Cultured human OA FLS were treated with IL-1ß alone and with pathway inhibitors or with synthetic liver X receptor (LXR) agonists. Cholesterol hydroxylases, ABC transporters, apolipoproteins (APO), LXR, sterol regulatory binding proteins (SREBPs), and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) were analyzed by RT-PCR, Western blot, and ELISA. The release of radiolabeled PLs from FLS was determined, and statistical analysis was performed using R (N = 5-9). (3) Results: Like synthetic LXR agonists, IL-1ß induced a 1.4-fold greater release of PLs from FLS. Simultaneously, IL-1ß upregulated the level of the PL transporter ABCA1 and of cholesterol hydroxylases CH25H and CYP7B1. IL-1ß and T0901317 stimulated the expression of SREBP1c, whereas only T0901317 enhanced SREBP2, HMGCR, APOE, LXRα, and ABCG1 additionally. (4) Conclusions: IL-1ß partially controls PL levels in OA-SF by affecting the release of PLs from FLS. Our data show that IL-1ß upregulates cholesterol hydroxylases and thus the formation of oxysterols, which, as natural agonists of LXR, increase the level of active ABCA1, in turn enhancing the release of PLs.
摘要：
（1）背景：骨关节炎（OA）膝关节滑液（SF）的磷脂（PL）水平升高。我们之前报道过TGF-β和IGF-1刺激成纤维细胞样滑膜细胞（FLS）合成的PLs量增加。目前的研究检查了IL-1β是否诱导FLS中PL的释放及其潜在机制。(2)方法:用单独的IL-1β和途径抑制剂或用合成的肝X受体(LXR)激动剂处理培养的人OAFLS。胆固醇羟化酶，ABC运输商，载脂蛋白（APO），LXR,甾醇调节结合蛋白（SREBPs），和3-羟基-3-甲基戊二酰辅酶A还原酶（HMGCR）的RT-PCR分析，蛋白质印迹,和ELISA。确定了放射性标记的PL从FLS的释放，使用R（N=5-9）进行统计分析。（3）结果：像合成的LXR激动剂，IL-1β诱导PLs从FLS释放1.4倍。同时,IL-1β上调PL转运体ABCA1和胆固醇羟化酶CH25H和CYP7B1的水平。IL-1β和T0901317刺激SREBP1c的表达，而只有T0901317增强了SREBP2，HMGCR，APOE,LXRα,和ABCG1另外。（4）结论：IL-1β通过影响从FLS释放PL来部分控制OA-SF中的PL水平。我们的数据显示，IL-1β上调胆固醇羟化酶，从而形成氧固醇，which,作为LXR的天然激动剂，增加活性ABCA1的水平，进而增强PLs的释放。
