Research for the reguration of the gene expression of glucose transporters in ischemic heart diseases and its application to gene therapy

缺血性心脏病中葡萄糖转运蛋白基因表达调控及其在基因治疗中的应用研究

• 批准号: 10670633
• 负责人: HIROE Michiaki
• 金额: $ 2.05万
• 依托单位: Tokyo Medical and Dental University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10670633/
• 关键词: GLUT1; GLUT4; Hypoxia

GLUT1 and GLUT4 are the primary isoforms of glucose transporters expressed in the myocardium. Expression of the GLUT1 gene has been shown to be increased in hypoxic cardiac myocytes. In the present study, we demonstrated hypoxia-mediated induction of GLUT4 gene expression in cultured neonatal rat cardiac myocytes exposed to persistent hypoxia. We also showed that the induction of GLUT1 and GLUT4 mRNAs upon hypoxia was much more abundant in cardiac myocytes than in non-myocytes. The induction of both mRNAs in hypoxic cardiac myocytes was completely abrogated by BAPTA-AM, suggesting the need for an elevated intracellular calcium ion concentration ([Ca^<2+>]_i) in this response. Furthermore, the induction of both mRNAs was attenuated by H7, suggesting the involvement of the protein kinase C (PKC) pathway as well. Nonetheless, our findings in this study suggest that GLUT1 and GLUT4 gene expressions are induced in distinctly different ways. To begin with, the time courses required for the induction of the two genes were different. Secondly, increases in [Ca^<2+>]_i at normoxia with A23187 or veratridine resulted in increases in GLUT1 mRNA but not in GLUT4 mRNA, suggesting that [Ca^<2+>]_i elevation alone is insufficient for the induction of GLUT4 mRNA.Thirdly, H7 only partially inhibited the induction of GLUT1 mRNA, but fully inhibited the induction of GLUT4 mRNA. These results suggest that [Ca^<2+>]_i elevation and PKC activation are both involved in the hypoxic induction of GLUT1 and GLUT4 gene expression, but that the regulatory mechanisms of these genes may differ in this process.

GLUT1和GLUT4是葡萄糖转运蛋白在心肌中表达的主要亚型。GLUT1基因的表达在缺氧心肌细胞中增加。在本研究中，我们证明了缺氧介导的GLUT4基因在暴露于持续缺氧的培养新生大鼠心肌细胞中的表达。我们还发现缺氧诱导的GLUT1和GLUT4 mrna在心肌细胞中比在非心肌细胞中更丰富。这两种mrna在缺氧心肌细胞中的诱导作用被BAPTA-AM完全消除，这表明在这种反应中需要提高细胞内钙离子浓度（[Ca^<2+>]_i）。此外，H7减弱了这两种mrna的诱导作用，表明也参与了蛋白激酶C （PKC）途径。尽管如此，我们在本研究中的发现表明，GLUT1和GLUT4基因的表达是通过明显不同的方式诱导的。首先，诱导两种基因所需的时间是不同的。其次，在常氧条件下，A23187或veratridine增加[Ca^<2+>]_i导致GLUT1 mRNA升高，而不是GLUT4 mRNA升高，表明单独升高[Ca^<2+>]_i不足以诱导GLUT4 mRNA。第三，H7仅部分抑制GLUT1 mRNA的诱导，但完全抑制GLUT4 mRNA的诱导。这些结果表明，[Ca^<2+>]_i升高和PKC激活都参与了缺氧诱导GLUT1和GLUT4基因表达，但这些基因在这一过程中的调节机制可能不同。