Palmitate induces interleukin-8 expression in human aortic vascular smooth muscle cells via Toll-like receptor 4/nuclear factor-κB pathway
Palmitate induces interleukin-8 expression in human aortic vascular smooth muscle cells via Toll-like receptor 4/nuclear factor-κB pathway
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DOI：
10.1111/1753-0407.12073
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发表时间：
2014-01-01
影响因子：
4.5
通讯作者：
Wang, Baoli
中科院分区：
文献类型：
--
作者：
Quan, Jinxing;Liu, Jing;Wang, Baoli
研究背景近年来研究表明，饱和游离脂肪酸(FFA)通过Toll样受体4(TLR4)途径诱导炎症反应。白介素8(IL-8)是一种促炎细胞因子，可在体外诱导血管平滑肌细胞的增殖和迁移。然而，棕榈酸酯对人血管平滑肌细胞IL-8表达的调节尚不清楚。本研究旨在探讨游离脂肪酸对人血管平滑肌细胞IL-8表达的调节及其可能的机制。方法用棕榈酸酯、多种信号转导抑制剂或TLR4 shRNA腺病毒处理培养的人血管平滑肌细胞，检测IL-8的mRNA和蛋白表达水平、核因子B荧光素酶活性和核因子B p65结合活性。棕榈酸酯对核因子B荧光素酶活性和核因子B p65结合活性均有显著的刺激作用，但用核因子B抑制剂帕特内酯处理后，两者的活性均显著降低。小白菊内酯预处理也可阻断棕榈酸酯诱导的IL-8mRNA和蛋白表达。相比之下，用豆蔻菌素和Wortmannin阻断神经酰胺和磷脂酰肌醇-3激酶(PI3K)通路并不影响棕榈酸酯诱导的IL-8表达。用钙磷蛋白C和白屈菜红碱抑制蛋白激酶C(PKC)的激活可部分抑制棕榈酸酯刺激的IL-8的表达，但对棕榈酸酯诱导的核因子-B的激活无影响。结论棕榈酸酯通过TLR4/NF-B途径诱导血管内皮细胞IL-8基因表达。
BackgroundRecent evidence demonstrates that saturated free fatty acids (FFAs) induce the inflammatory response via the Toll-like receptor 4 (TLR4) pathway. Interleukin-8 (IL-8) is a proinflammatory cytokine that induces vascular smooth muscle cell proliferation and migration in vitro. However, the regulation of IL-8 expression by palmitate in human vascular smooth muscle cells (HVSMCs) has not been clarified. The aim of this study was to investigate the regulation of IL-8 expression by free fatty acids and determine the underlying mechanisms in HVSMCs.MethodsHuman vascular smooth muscle cells were cultured and treated with palmitate, various signaling inhibitors or TLR4 shRNA adenovirus, and the mRNA and protein expression levels of IL-8, nuclear factor B (NF-B) luciferase activity and NF-B p65 binding activity were studied.ResultsPalmitate induced IL-8 mRNA expression and secretion in a dose-dependent manner. Palmitate significantly stimulated both nuclear factor B (NF-B) luciferase activity and NF-B p65 binding activity, which were markedly diminished by pretreatment with the NF-B inhibitor, parthenolide. Parthenolide pretreatment also abolished IL-8 mRNA and protein induction by palmitate. By contrast, disrupting the ceramide and phosphoinositide-3 kinase (PI3K) pathways with myriocin and wortmannin did not affect palmitate-induced IL-8 expression. Inhibition of protein kinase C (PKC) activation with calphostin C and chelerythrine partially suppressed palmitate-stimulated IL-8 expression, but it had no effect on palmitate-induced NF-B activation. Finally, knockdown of TLR4 markedly abolished palmitate-induced NF-B activation and IL-8 expression.ConclusionsPalmitate induces IL-8 gene expression in HVSMCs through the TLR4/NF-B pathway.