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

通过测定人脐静脉内皮细胞(HUVECs)内钙离子浓度([Ca^&lt；2&gt；]i)、全细胞膜电流和单通道活性，研究了神经鞘氨醇-1-磷酸(S1P)激活的人脐静脉内皮细胞(HUVECs)内钙内流途径。S1P作用于人脐静脉内皮细胞可引起细胞内[Ca^&lt；2&gt；_i]缓慢增加，当浴液中无钙时，S1P对[Ca^&lt；2&gt；]_i无影响，但在S1P的存在下，[Ca^&lt；2&gt；i]持续增加，提示钙的内流在S1P升高[Ca^&lt；2&gt；_i中起强制作用。用百日咳毒素(Ptx)预处理HUVECs可阻断S1P引起的[Ca1+]_i升高。当在[Ca1；lt；2&gt；]_i监测下记录到全细胞膜电流时，施加S1P可诱发微小的内向电流([Ca^&lt；S1p&gt；]i)，随后[Ca^&lt；2&gt；]i的反转电位为*-selec…。更活泼的阳离子(NSC)电流。当S1P被加入到自内向外膜片钳结构的吸管溶液中时，电导为17ps的单通道被激活，这取决于细胞内GTP的存在。这些结果表明，S1P具有一种新的功能，即通过PTX敏感的G蛋白以GTP依赖的方式激活NSC通道。S1P激活的NSC通道在血管内皮细胞中起钙通道的作用，可能调节细胞增殖。这些结果已发表在《物理学杂志》上。(537,431-441,2001)2002研究了棕榈酰卡尼汀(Palcar)对人脐静脉内皮细胞[Ca~(2+)]_i的影响，并与S1P进行了比较。[Ca~(2+)]_i在人脐静脉内皮细胞中的应用，其效价约为S1P的30倍。每个HUVEC对3μM Palcar的反应与对0.3μM S1P的反应明显平行。此外，PTX处理的HUVEC对Palcar的反应与对S1P的反应一样不明显。这些结果表明，Palcar作为一种潜在的S1P受体激动剂对Huves具有新的作用。这些研究结果已发表在《药理学杂志》上。SCI。(印数，2003)减少

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