The roles in agonist-induced morphological mechanisms in cultured human umbilical vein endothelial cells.

血管内皮是血管壁的内层，对各种底物具有选择性的转运作用。还已知内皮细胞是炎症介质的靶标，其引起包括血管通透性增加的各种功能。我们使用组胺作为炎症介质，通过延时分析培养的人脐静脉内皮细胞，研究激动剂诱导的形态学变化的作用。通过细胞内Ca^2+浓度的变化和细胞骨架的变化来研究炎症细胞内信号转导的机制。组胺引起细胞周边的短暂收缩，这与细胞间连接的松动相一致。H^1受体拮抗剂异丙嗪可阻断这种变化，而H_2受体拮抗剂则不能阻断这种变化。这种收缩依赖于细胞外的Ca^<2+>。组胺引起[Ca^&lt;2+&gt;] _的双相增加<in>。第一个阶段是短暂的，第二个阶段是开启的。 ...更多信息 E是持续的。H_1拮抗剂对组胺诱导的胞浆Ca^&lt;2+&gt;升高有效。这些结果表明组胺激活H^1受体。然后，Ca^2+的流入促进肌醇磷脂转换的破坏和激活蛋白激酶C（PKC），其反过来磷酸化各种细胞蛋白，包括细胞因子相关蛋白。二甘油是磷脂分解的产物之一，是蛋白激酶C的激活剂，被发现具有类似组胺的形态学效应。另一方面，另一种PKC增强剂PMA诱导的双相形态学变化与组胺不同。第一阶段为细胞周边收缩期，第二阶段为细胞伸长延迟期。PKC抑制剂、酪氨酸激酶抑制剂和蛋白质合成抑制剂仅抑制第二时相，这一事实有力地表明组胺作用涉及多个信号通路。除了PKC激活外，另一条途径可能通过激活蛋白酪氨酸激酶在组胺诱导的形态学改变中起关键作用。少

Vascular endothelium constitutes the inner lining of vascular wall and acts as a selective varrier to various substrates. It is also known that endothelial cells are targets of inflammatory mediators which cause various functions including an increase in vascular permeability. We investigated the roles of agonist-induced morphological changes by time-lapse analysis in cultured human umbilical vein endothelial cells using histamine as an inflammatory mediator. The mechanisms of intracellular signal transductions in inflammation were investigated by the movement of cytosolic Ca^<2+> concentrations and cytoskeletal events. Histamine induced transient shrinkage of cell periphery which coincided with loosening of cell to cell junctions. This change was abolished by promethazine, an antagonist of H^1 receptor, but not H_2 antagonist. This shrinkage was dependent upon extracellular Ca^<2+>. Histamine induced biphasic increase in [Ca^<2+>] _<in>. The first phase was transient and the second on … More e was sustained. An H_1 antagonist was effective on histamine-induced increase in cytosolic Ca^<2+>. These results suggest that histamine activates H^1 receptors. Then influx of Ca^<2+> promotes breakdown of inosytolphospholipid turnover and activation protein kinase C (PKC) which in turn phosphorylates various cellular proteins including cytoskeleton-associated proteins. Diglycerol, one of the products of phospholipid breakdown and an activator of PKC,was found to mimic morphological effect of histamine. On the other hand PMA,another PKC potentiator, induced biphasic morphological changes which is different from that of histamine. The first phase was shrinkage of cell periphery and the second one was delayd elongation of cells. The facts that only the second phase was inhibited by PKC inhibitor, tyrosine kinase inhibitor and protein synthesis inhibitor strongly suggest multiple signaling pathways are involved in histamine action. In addition to PKC activation another pathways presumably through activation of protein tyrosine kinase might play a crucial role in histamine-induced morphological change. Less