FLUID SHEAR-STRESS INDUCES A BIPHASIC RESPONSE OF HUMAN MONOCYTE CHEMOTACTIC PROTEIN-1 GENE-EXPRESSION IN VASCULAR ENDOTHELIUM
FLUID SHEAR-STRESS INDUCES A BIPHASIC RESPONSE OF HUMAN MONOCYTE CHEMOTACTIC PROTEIN-1 GENE-EXPRESSION IN VASCULAR ENDOTHELIUM
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DOI：
10.1073/pnas.91.11.4678
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发表时间：
1994-05-24
影响因子：
11.1
通讯作者：
CHIEN, S
中科院分区：
文献类型：
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作者：
SHYY, YJ;HSIEH, HJ;CHIEN, S
动脉粥样硬化病变在动脉树上的局灶性分布与血流产生的局部剪应力有关，但这些病变易发区域内皮细胞致动脉粥样硬化反应的分子基础尚不清楚。我们报道了剪应力介导血管内皮细胞(EC)单核细胞趋化蛋白1(MCP-1)基因表达的双相反应。Northern印迹分析表明，人脐静脉内皮细胞(HUVEC)在16dynes/cm(2)(1dynes=10mN)的剪切力作用1.5小时后，MCP-1mRNA的表达水平较静态细胞增加了2~3倍。MCP-1基因表达在剪切开始后4小时降至基础水平，5小时后进一步下降至完全静止。一旦基因表达被完全抑制，即使在静态孵育1.5小时后，它也保持静止，并且在这种静态孵育后对重新倾听没有反应。然而，如果剪切后孵育时间从1.5小时延长到24小时，MCP-1mRNA恢复到基础水平，然后在再次施加剪应力后能够增加。核连续实验表明，剪切诱导的HUVEC MCP-1mRNA表达上调是在转录水平上的调控。用放线菌亚胺研究表明，切应力诱导MCP-1的形成不需要从头合成蛋白质。在剪切力为6、16或32dynes/cm(2)的实验中发现MCP-1基因表达的双相反应，不仅在HUVEC中观察到这种反应，而且在HeLa细胞、胶质瘤细胞系和皮肤成纤维细胞中也观察到这种反应。这项体外研究表明，MCP-1基因对切应力的反应代表了早期基因的即刻激活，并提示该基因在持续切应力下的EC中可能受到抑制。
The focal distribution of atherosclerotic lesions in the arterial tree is related to the local shear stress generated by blood flow, but the molecular basis of the atherogenic response of endothelial cells in these lesion-prone areas is still unclear. We report that shear stress mediates a biphasic response of monocyte chemotactic protein 1 (MCP-1) gene expression in vascular endothelial cells (EC). Northern blot analysis indicated that the level of MCP-1 mRNA in human umbilical vein EC (HUVEC) subjected to a shear stress of 16 dynes/cm(2) (1 dyne = 10 mu N) for 1.5 hr increased by 2- to 3-fold when compared with static cells. The MCP-1 gene expression decreased to the basal level at 4 hr and then declined further to become completely quiescent at 5 hr after the onset of shear. Once the gene expression was fully suppressed, it remained quiescent even after static incubation for 1.5 hr and would not respond to reshearing after this static incubation. However, if the postshearing incubation extended from 1.5 to 24 hr, the MCP-1 mRNA returned to the basal level and was then able to increase after the reapplication of shear stress. Nuclear run-on experiments showed that the shear-induced increased MCP-1 mRNA in HUVEC was regulated at the transcriptional level. By using cycloheximide, it was shown that de novo protein synthesis was not necessary for the induction of MCP-1 by shear stress. The biphasic response of MCP-1 gene expression was found in experiments in which the applied shear stress was 6, 16, or 32 dynes/cm(2), and it was observed not only in HUVEC but also in HeLa cells, glioma cell lines, and skin fibroblasts. This in vitro study demonstrates that the response of MCP-1 gene to shear stress represents an immediate early gene activation and suggests that this gene is probably suppressed in EC that have been exposed to a constant shear stress.