Relationship between lipid mediator receptors and lipid-induced impairment of human endothelial cells

2001通过测量细胞内Ca^<2+>浓度（[Ca^<2+] i）、全细胞膜电流和单通道活性，研究了1-磷酸鞘氨醇（S1 P）激活的人脐静脉内皮细胞（HUVECs）Ca ^<2+进入途径。应用S1 P对HUVECs诱导[Ca^<2+>_i]缓慢发展的增加。在无Ca^<2+>存在的情况下，S1 P对[Ca^<2+] i无影响，但在有S1 P存在的情况下，加入Ca^<2+] i可使[Ca^<2+] i持续升高，提示Ca^<2+内流在S1 P升高[Ca^<2+] i中起着必然的作用。用百日咳毒素（PTX）预处理HUVECs可阻断S1 P诱导的[Ca^<2+>] i升高。在[Ca^2+] i监测下记录全细胞膜电流时，S1 P诱导了一个微小的内向电流（I<S1P>），随后[Ca^2+] i升高。I_2的反转电位<S1P>表明，I_2<S1P>是一个 *-选择性离子。 ...更多信息 阳离子（NSC）电流。当S1 P被包括在移液器溶液中时，在切除的由内而外的膜片钳配置中，取决于细胞内GTP的存在，具有17 pS电导的 *gle通道被激活。这些结果表明，S1 P具有通过PTX敏感的G蛋白以GTP依赖性方式激活NSC通道的新功能。S1 P激活的神经干细胞通道作为内皮细胞内Ca^2+进入的通道，可能参与细胞增殖的调节。这些结果已经发表在J. Physiol.（537，431-441，2001）2002中，在HUVEC中检测了棕榈酰肉碱（palmitoylcarnitine，palcar）（一种在缺血条件下从各种类型的细胞释放的脂质）对[Ca^2+]_i的影响，并与S1 P的影响进行了比较。palcar的应用使HUVECs内[Ca^&lt;2+&gt;]_i升高，其作用强度比S1 P低约30倍。在每个HUVEC中，对3 μM palcar的反应明显优于0.3 μM S1 P。此外，用PTX处理的HUVEC对palcar和S1 P均无反应。这些结果表明，palcar作为S1 P受体的潜在激动剂对huvecs具有新的作用。这些结果已发表在J. Pharmacol。Sci. (in 2003年）减

2001Ca^<2+> entry pathway activated by sphingosine-1-phosphate (S1P) was examined in human umbilical vein endothelial cells (HUVECs) by measuring intracellular Ca^<2+> concentration ([Ca^<2+>]_i), whole-cell membrane currents and single channel activity. Application of S1P to HUVECs induced a slowly developing increase in [Ca^<2+>_i. When Ca^<2+> was absent in the bathing solution, S1P did not affect [Ca^<2+>]_i Addition of Ca^<2+> to the bathing solution, however, produced a sustained increase in [Ca^<2+>_i in the presence of S1P, suggesting that influx of Ca^<2+> plays an obligatory role in elevation of [Ca^<2+>_i by S1P. Pretreatment of HUVECs with pertussis toxin (PTX) abolished S1P-induced elevation of [Ca^<2+>]_i. When whole-cell membrane currents were recorded under the monitoring of [Ca^<2+>]_i, the application of S1P induced a tiny inward current (I_<S1P>) which was followed by the elevation of [Ca^<2+>]_i. The reversal potential of I_<S1P> revealed that I_<S1P> is a ***-selec … More tive cation (NSC) current. When S1P was included in the pipette solution in the excised inside-out patch clamp configuration, ***gle channel with a conductance of 17 pS was activated, depending on the presence of intracellular GTP. These results suggest that S1P has a novel function to activate a NSC-channel in a GTP-dependent manner via a PTX-sensitive G-protein. The NSC-channel activated by S1P acts as a Ca^<2+> entry pathway in endothelium and may regulate the cell-proliferation. These results have been published in J. Physiol. (537, 431-441, 2001)2002Effects of palmitoylcarnitine (palcar), a lipid that is released from various types of cells under the ischemic conditions, on [Ca^<2+>]_i were examined in HUVECs and compared with those of S1P. Application of palcar elevated [Ca^<2+>]_i in HUVECs and its potency was about 30 times lower than that of S1P. Response to 3 μM palcar in each HUVEC clearly paralleled that to 0.3 μM S1P. In addition, HUVECs that were treated with PTX failed to respond to palcar as werll as to S1P. These results suggest that palcar has a novel action on huvecs as a potential agonist of receptors for S1P. These results have been published in J. Pharmacol. Sci. (in press, 2003) Less