Lysophosphatidic acid induces shear stress-dependent Ca2+ influx in mouse aortic endothelial cells in situ
Lysophosphatidic acid induces shear stress-dependent Ca2+ influx in mouse aortic endothelial cells in situ
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DOI：
10.1113/expphysiol.2011.056416
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发表时间：
2011-04-01
影响因子：
2.7
通讯作者：
Momose, Kazutaka
中科院分区：
文献类型：
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作者：
Ohata, Hisayuki;Yamada, Hideyuki;Momose, Kazutaka
使用实时双光子激光扫描显微镜，我们证明了溶血磷脂酸（LPA）是一种生物活性脂质介质，可在原位分离的小鼠主动脉带的负载fluo-4的内皮细胞中引起剪切应力依赖性细胞内Ca2+浓度（[Ca2+](i)）振荡局部增加。 [Ca2+](i) 的增加在单个内皮细胞中以逐步方式独立发生或在恒定流量期间重复发生。响应的细胞百分比和 [Ca2+](i) 增加的平均水平取决于 LPA 浓度 (0.3-10 μ m) 和剪切应力 (10-80 dyn cm(-2))。去除细胞外 Ca2+ 可抑制该反应，但毒胡萝卜素（内质网 Ca2+-ATP 酶抑制剂）则不会抑制该反应。 [Ca2+](i) 响应的时空特性与 ATP（一种 Ca2+ 动员激动剂）诱导的 Ca2+ 波的时空特性完全不同。这些结果与之前使用培养的牛主动脉内皮细胞进行的研究几乎相同，表明 LPA 通过激活基本 Ca2+ 内流增强了内皮细胞中剪切应力诱导的振荡 Ca2+ 内流，称为“Ca2+ 点”。总之，本研究首次证明，LPA 作为内源性敏化剂，在主动脉带原位以及培养细胞的剪切条件下，用于内皮细胞的机械转导。这表明 LPA 作为内源性因子在流体流动诱导的内皮功能中发挥着重要作用。
Using real-time two-photon laser scanning microscopy, we have demonstrated that lysophosphatidic acid (LPA), a bioactive lipid mediator, causes shear stress-dependent oscillatory local increase in intracellular Ca2+ concentration ([Ca2+](i)) in fluo-4-loaded endothelial cells of isolated mouse aortic strips in situ. The increase in [Ca2+](i) occurred independently in the individual endothelial cells in a stepwise manner or repetitively during constant flow. The percentage of cells that responded and the averaged level of increase in [Ca2+](i) were dependent on both the concentration of LPA (0.3-10 mu m) and the shear stress (10-80 dyn cm(-2)). The response was inhibited by removing extracellular Ca2+, but not by thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+-ATPase. The spatiotemporal properties of the [Ca2+](i) response were completely different from those of a Ca2+ wave induced by ATP, a Ca2+-mobilizing agonist. These results were almost the same as those in the previous investigation using cultured bovine aortic endothelial cells, and suggest that LPA enhanced the shear stress-induced oscillatory Ca2+ influx, termed 'Ca2+ spot', in endothelial cells via activation of elementary Ca2+ influx. In conclusion, the present study demonstrates, for the first time, that LPA functions as an endogenous sensitizer for mechanotransduction in endothelial cells in shear conditions in aortic strips in situ as well as in cultured cells. This indicates an important role for LPA as an endogenous factor in fluid flow-induced endothelial function.