Activation of phospholipase C/Ca^<2+> system in thyroid cells and its physiological and pathological roles.

甲状腺细胞磷脂酶C/Ca^2系统的激活及其生理病理作用。

基本信息

批准号：
07457217
负责人：
OKAJIMA Fumikazu
金额：
$ 4.16万
依托单位：
Gunma University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

We have recently found that adenosine inhibits TSH-induced activation of adenylyl cyclase/cAMP system and enhances TSH-induced activation of phospholipase C/Ca^<2+> system in rat thyroid cells. In thyroid cells, in addition to norepinephrine, acetylcholine and ATP,lysosphingolipids such as sphingosine 1-phosphate (SlP) and sphingosylsphosphorylcholine (SPC) has also been suggested to be a potent Ca^<2+> mobilizer. In this study, we planned to clarify the roles of phospholipase C/Ca^<2+> system in thyroid cells. We obtained the following novel findings. (1) In human thyroid cells as well, it was demonstrated that phospholipase C/Ca^<2+> system was regulated through the cross-talk of TSH and adenosine. (2) To clarify the cross-talk mechanism by which TSH and adenosine regulate phospholipase C activity, we used in vivo Cos-7 cell reconstitution system, in which cDNAs encoding receptors, each wild type G-protein subunit and mutant subunit. We found that adenosine-induced modification of two TSH-induced responses were mediated by a single type of Gi protein, Gi2 or Gi3 ; alpha subunit mediates inhibition of AC and betagamma subunits activation of phospholipase C.(3) Grave's IgG in the presence of adenosine induced activation of phospholipase C/Ca^<2+> system, and hence it was suggested that the measurement of phospholipase C/Ca^<2+> system is applied for a novel diagnosis of Grave's disease. (4) SlP and SPC regulated phospholipase C/Ca^<2+> system, H_2O_2 generation, cell proliferation and so on in thyroid cells. Thus, these lipid mediators were suggested to be novel agonists in these cells.

我们最近发现，腺苷抑制TSH诱导的腺苷酸环化酶/cAMP系统的激活，并增强了大鼠甲状腺细胞中TSH诱导的磷脂酶C/Ca^<2+>系统的激活。在甲状腺细胞中，除去甲肾上腺素，乙酰胆碱和ATP外，还建议溶酶磷脂，例如1-磷酸盐（SLP）和鞘磷酸磷酸胆碱（SPC）。在这项研究中，我们计划阐明磷脂酶C/Ca^<2+>系统在甲状腺细胞中的作用。我们获得了以下新颖的发现。（1）在人甲状腺细胞中，也证明了磷脂酶C/Ca^<2+>系统通过TSH和腺苷的串扰调节。（2）为了阐明TSH和腺苷调节磷脂酶C活性的串扰机制，我们在体内COS-7细胞重建系统中使用了编码受体的CDNA，每个野生型G蛋白亚基和突变体亚基。我们发现，腺苷诱导的两种TSH诱导反应的修饰是由一种类型的GI蛋白GI2或GI3介导的。 α亚基介导了磷脂酶C的AC和Betagamma亚基的抑制。（3）在存在腺苷诱导的磷脂酶C/Ca^<2+>系统的激活的情况下，Grave的IgG，因此，因此建议对磷脂酶C/Ca^<2>系统的测量进行诊断。（4）SLP和SPC调节磷脂酶C/Ca^<2+>系统，H_2O_2生成，细胞增殖等。因此，这些脂质介质被认为是这些细胞中的新型激动剂。