Effects of extracellular environments on development and differenciation of cardiac ion channels

细胞外环境对心脏离子通道发育和分化的影响

• 批准号: 07407073
• 负责人: TOYAMA Junji
• 金额: $ 1.28万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 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
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07407073/
• 关键词: cultured cardiomyocytes; ion channels; growth factor; differentiation; mesoderm; commitment; 中胚葉イオンチャネル; 分化; コミットメント; 成長因子; 培養心筋

This study was aimed to investigate terminal differentiaiotn of cardiac progenitor cells in the early embryogenesis, and ionic currents development after birth in relation to exogenous influence. We heve already established culture systems of the mouse gastrula mesoderm and rat neonatal ventricular myocytes.Our study in early cardiogenesis indicates that at 7.5 days post coitum, when gastrulation is completed, mesodermal cardiac progenitor cells commit to autonomous differentiation into contractile cardiomyocytes, while 7.25 day post coitum mesoderm requires additional signaling for terminal differentiation. Insulin, insulin-like growth factor and platelet derived growth factor induced cardiomyocytes with spontaneous beating.In ionic current analysis of neonatal rat ventricular myocytes cultured for 5-15 days, development of ionic currents, especially of I_<to>, showed various patterns, which were dependent on culture states. Hypoxic culture condition retarded or dedifferentiated I_<to> development. Basic fibroblast growth factor enhanced development of I_<to>. Insulin-like growth factor increased the percentage of cells expressing I_<Kur>. In order to explore the molecular mechanism of developmental changes in ionic currents induced by culture condition, we are engaged in microinjection of the exogenous mRNA into cultured cardiomyocytes.The changes of culture condition, such as hypoxia and modification of culture medium, regulated the ion channels expression. Our findings suggest that environmental factors play important role in ionic channels development as well as in the early cardiogenesis.

本研究旨在探讨心脏前体细胞在胚胎早期的终末分化及出生后离子电流的发育与外源性影响的关系。我们已经建立了小鼠原肠胚中胚层和新生大鼠心室肌细胞的培养体系，我们对早期心脏发生的研究表明，在胚胎发育后7.5天，原肠胚形成完成时，中胚层心脏祖细胞致力于自主分化为收缩性心肌细胞，而胚胎发育后7.25天的中胚层需要额外的终末分化信号。用胰岛素、胰岛素样生长因子和血小板源性生长因子诱导心肌细胞自发搏动，对培养5-15天的乳鼠心室肌细胞进行离子电流分析，发现心肌细胞的离子电流，特别是I_2的发展<to>呈现出不同的模式，并与培养状态有关。低氧培养条件下，I_2发育迟缓或去分化<to>。碱性成纤维细胞生长因子促进I_2的发育<to>。胰岛素样生长因子增加表达I_的细胞百分比<Kur>。为了探讨培养条件引起心肌细胞离子电流发育性变化的分子机制，我们将外源性mRNA注射到培养的心肌细胞中，通过改变培养条件，如缺氧和培养基的改变，调节心肌细胞离子通道的表达。我们的研究结果表明，环境因素在离子通道的发育以及早期心脏发生中起着重要作用。

项目成果

Arai A,Yamamoto K,Yamamura H,Toyama J: "Insulin promotes the differentiation of cardiac progenitor cells in the mouse embryos." Environmental Medicine. 40 (In press). (1996)

Arai A、Yamamoto K、Yamamura H、Toyama J：“胰岛素促进小鼠胚胎中心脏祖细胞的分化。”

Arai A,Kodama I,Toyama J: "Roles of C1-channels and Ca2+ mobilization in the stretch-induced increase of SA node pacemaker activity." Am J Physiol in press. (1995)

Arai A、Kodama I、Toyama J：“C1 通道和 Ca2 动员在拉伸诱导的 SA 结起搏器活动增加中的作用。”

Ohsugi M,Yamamura H,Semba R and Hideka H: "Immunocytochemical detection of Ca2+-dependent subspoecies ot protein kinase C in mouse embryos before and during compaction." The Histochemical Journal. 26. 641-643 (1994)

Ohsugi M、Yamamura H、Semba R 和 Hideka H：“在压缩之前和压缩过程中对小鼠胚胎中 Ca2 依赖的蛋白激酶 C 亚种进行免疫细胞化学检测。”

Guo W,Kamiya K,Cheng J Toyama J: "Changes in action potentials and ion currents in long-term cultured neonatal rat ventricular cells." Am J Physiol (Cell Physiol). 271. C93-C102 (1996)

Guo W，Kamiya K，Cheng J Toyama J：“长期培养的新生大鼠心室细胞动作电位和离子电流的变化。”

Watanabe E,Honjo H,Anno T,Boyett MR,Kodama I,Toyama J:"Modulation of pacemaker activity of sinoatrial node cells by electrical load imposed by an atrial cell model." Am J Physiol. 269. H1735-H1742 (1995)

Watanabe E、Honjo H、Anno T、Boyett MR、Kodama I、Toyama J：“通过心房细胞模型施加的电负载调节窦房结细胞的起搏器活动。”