Lo C J, Fu M, Lo F R
Department of Surgery, University of California, Los Angeles 90095-6904, USA.
J Surg Res. 1998 May;76(2):159-64. doi: 10.1006/jsre.1998.5312.
Vascular endothelial cells (EC) play a pivotal role in diffuse organ injury seen in ARDS and MOFS. On exposure to cytokines or endotoxin (LPS) EC are stimulated to express adhesion molecules as well as proinflammatory and procoagulant activity. However, the potential feedback control of EC on macrophages (M-theta) is not clear. We studied the cellular mechanism of iloprost, a PGI2 analogue, in regulation of TNF production by LPS-stimulated M-theta.
Rabbit alveolar M-theta and mouse M-theta RAW 264.7 cells were exposed to Escherichia coli LPS in the presence of various concentrations of iloprost. TNF production was measured by L929 bioassays. To further study the cellular mechanism of iloprost on M-theta activation, RAW 264.7 cells were stimulated by LPS (10 micrograms/ml) in the presence of either iloprost or specific mitogen-activated protein kinase (MAPK) inhibitors, either PD98059 or SB202190. P44/P42 and P38 MAPK activation were evaluated by Western blot assays with anti-phospho MAPK antibodies.
LPS induced M-theta TNF production, which was inhibited by iloprost. Iloprost also attenuated the activation of P44/P42 and P38 induced LPS. Inhibition of P44/P42 with PD98059 or P38 with SB202190 significantly reduced TNF production by LPS-stimulated RAW cells.
The regulatory mechanism of EC on M-theta activation is dependent on PGI2. The effect of PGI2 on M-theta is, at least in part, mediated through inhibiting MAPKs.
血管内皮细胞（EC）在急性呼吸窘迫综合征（ARDS）和多器官功能障碍综合征（MOFS）中所见的弥漫性器官损伤中起关键作用。暴露于细胞因子或内毒素（LPS）时，EC会被刺激表达黏附分子以及促炎和促凝活性。然而，EC对巨噬细胞（M-θ）的潜在反馈控制尚不清楚。我们研究了前列环素类似物伊洛前列素调节LPS刺激的M-θ产生肿瘤坏死因子（TNF）的细胞机制。
将兔肺泡M-θ和小鼠M-θ RAW 264.7细胞在不同浓度的伊洛前列素存在下暴露于大肠杆菌LPS。通过L929生物测定法测量TNF的产生。为了进一步研究伊洛前列素对M-θ激活的细胞机制，RAW 264.7细胞在存在伊洛前列素或特异性丝裂原活化蛋白激酶（MAPK）抑制剂（PD98059或SB202190）的情况下用LPS（10微克/毫升）刺激。用抗磷酸化MAPK抗体通过蛋白质印迹分析评估P44/P42和P38 MAPK的激活。
LPS诱导M-θ产生TNF，而伊洛前列素可抑制该过程。伊洛前列素还减弱了LPS诱导的P44/P42和P38的激活。用PD98059抑制P44/P42或用SB202190抑制P38可显著降低LPS刺激的RAW细胞产生的TNF。
EC对M-θ激活的调节机制依赖于前列环素（PGI2）。PGI2对M-θ的作用至少部分是通过抑制MAPKs介导的。
