To investigate the effects of serum amyloid A1 (SAA1) on lipopolysaccharide (LPS) -induced inflammation in vascular smooth muscle cells (VSMCs). SAA1 expression was detected in LPS induced VSMCs at different concentrations for different time by using Western blotting. After pre-incubation with recombinant SAA1 protein, VSMCs were treated with 1 μg/ml LPS for 24 h. The VSMCs were then divided into Control, SAA1 siRNA, Nox4 siRNA, LPS, LPS + SAA1 siRNA, LPS + Nox4 siRNA and LPS + SAA1 siRNA + Nox4 groups. MTT was performed to observe the toxicity of VSMCs. Lucigenin-enhanced chemiluminescence method was used to detect superoxide anion (O2−) production and NADPH oxidase activity. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine expressions of inflammatory factors. Western blotting was used to determine expressions of NOX-4 and p38MAPK/NF-κB pathway related proteins. LPS promoted SAA1 protein expression in a concentration−/time-dependent manner. Recombinant SAA1 protein could increase NOX4/ROS production and promote the release of inflammatory factors (IL-1β, IL-6, IL-8, IL-17, TNF-α and MCP-1) in LPS (1 μg/ml) - induced VSMCs. Besides, both SAA1 siRNA and NOX-4 siRNA could not only enhance the O2− production and NADPH oxidase activity, but also up-regulate the protein expression of NOX4, the release of inflammatory factors, and the levels of p-p38 and p-NF-κB p65 in LPS-induced VSMCs. However, no significant differences in each index were observed between LPS group and LPS + SAA1 siRNA + Nox4 group. SAA1-mediated NOX4/ROS pathway could activate p38MAPK/NF-κB pathway, thereby contributing to the release of inflammatory factors in LPS-induced VSMCs.

中文翻译：

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SAA1通过激活p38MAPK /NF-κB途径增加NOX4 / ROS的产生以促进LPS诱导的血管平滑肌细胞炎症

调查血清淀粉样蛋白A1（SAA1）对脂多糖（LPS）诱导的血管平滑肌细胞（VSMC）炎症的影响。通过Western印迹在不同时间，不同浓度的LPS诱导的VSMC中检测到SAA1表达。与重组SAA1蛋白预孵育后，将VSMC用1μg/ ml LPS处理24小时。然后将VSMC分为对照组，SAA1 siRNA，Nox4 siRNA，LPS，LPS + SAA1 siRNA，LPS + Nox4 siRNA和LPS + SAA1 siRNA + Nox4组。进行MTT以观察VSMC的毒性。荧光素增强化学发光法用于检测超氧阴离子（O2-）的产生和NADPH氧化酶的活性。实时定量聚合酶链反应（qRT-PCR）用于确定炎症因子的表达。用蛋白质印迹法检测NOX-4和p38MAPK /NF-κB途径相关蛋白的表达。LPS以浓度/时间依赖性方式促进SAA1蛋白表达。重组SAA1蛋白可以增加LPS（1μg/ ml）中NOX4 / ROS的产生并促进炎性因子（IL-1β，IL-6，IL-8，IL-17，TNF-α和MCP-1）的释放-诱导的VSMC。此外，SAA1 siRNA和NOX-4 siRNA不仅可以提高O2-的产生和NADPH氧化酶的活性，而且还可以上调NOX4的蛋白表达，炎性因子的释放以及p-p38和p-p-的水平。 LPS诱导的VSMC中的NF-κBp65。但是，LPS组与LPS + SAA1 siRNA + Nox4组之间的各项指标均无显着差异。SAA1介导的NOX4 / ROS途径可以激活p38MAPK /NF-κB途径，