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Molecular Pharmacology of Capacitative Ca^<2+> Entry Channel of Human Aortic Endothelial Cell

人主动脉内皮细胞电容性Ca^<2>进入通道的分子药理学

基本信息

批准号：
12670080
负责人：
IIJIMA Toshihiko
金额：
$ 2.5万
依托单位：
Akita University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12670080/
关键词：
human aortic endothelial cells voltage clamp intracellular Ca^<2+> concentration Ca^<2+> ATPase antisense capacitative Ca^<2+> entry Cl^- channel TRPC4 Cl^-チャネル TRPC4バリアント HEK-293細胞細胞膜Ca^<2+>ATPase TRP4

项目摘要

In vascular endothelial cells, intracellular Ca^<2+> concentration ([Ca^<2+>]_i) increases in response to various vasoactive substances and mechanical stimulation, causing synthesis and release of endothelial active molecules.In this study, 1) human aortic endothelial cells were treated with antisense oligodeoxynucleotides targeting the 5' translation start site of the human membrane Ca^<2+> ATPase isoform 1. Results provide the evidence of functional role of plasma membrane Ca^<2+> ATPase, although other mechanisms including Na^+/Ca^<2+> exchange may play the primary role in regulating [Ca^<2+>]i.2) To examine the functional relationship between the increase in [Ca^<2+>]i and the Cl^- current, we investigated the effects of mibefradil on [Ca^<2+>]i and the Cl^- current increased by histamine in human aortic endothelial cells. Mibefradil decrease the histamine-induced [Ca^<2+>]i elevation and Cl^- current in a concentration-dependent manner. Those results indicate, the functional relationship between the capacitative Ca^<2+> entry channel and the Cl^- channel.And, 3) we isolated three (α, β, γ) TRPC4 variants, thought to be candidates for the molecular basis of capacitative Ca^<2+> entry channels, from rat brain cDNA using RT-PCR. In HEK-293 cells, basal [Ca^<2+>]i was increased, but carbachol or thapsigargin-induced Ca^<2+> entry were not affected by expression of rTRPC4α. Results indicate that rTRPC4α is functionally involved in the regulation of basal Ca^<2+> levels when transiently expressed in HEK-293 cells and may need intracellular factors for acting as the capacitative Ca^<2+> entry channel.

在血管内皮细胞中，细胞内Ca^2+浓度（[Ca^2+] i）随着血管活性物质和机械刺激的增加而增加，引起内皮活性分子的合成和释放。结果提供了质膜Ca^2+ ATP酶功能作用的证据，尽管包括Na^+/Ca^2+交换在内的其他机制可能在调节[Ca^2+] i中起主要作用。2）为了研究[Ca^2+]i增加与Cl^-电流之间的功能关系，我们研究了米贝拉地尔对组胺引起的人主动脉内皮细胞[Ca^<2+>]i和Cl^-电流的影响。米贝拉地尔以浓度依赖性方式降低组胺诱导的[Ca^<2+>]i升高和Cl^-电流。3）我们利用RT-PCR技术从大鼠脑cDNA中分离到了TRPC 4的三个变体（α、β、γ），它们被认为是容量性Ca^<2+>进入通道的分子基础。在HEK-293细胞中，基础[Ca^2+]i增加，但卡巴胆碱或毒胡萝卜素诱导的Ca^2+内流不受rTRPC 4 α表达的影响。结果表明，rTRPC 4 α在HEK-293细胞中瞬时表达时，在功能上参与基础Ca^2+水平的调节，并且可能需要细胞内因子作为容量性Ca^2+进入通道。