Effects of neurotoxic chemicals on brain creatine kinase activities and its genetic expression

神经毒性化学物质对脑肌酸激酶活性及其基因表达的影响

• 批准号: 14570313
• 负责人: IGISU Hideki
• 金额: $ 2.37万
• 依托单位: University of Occupational and Environmental Health
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14570313/
• 关键词: acrylamide; ethylene oxide; methyl bromide; brain; creatine kinase; mRNA; ATP; neurotoxicity

We have found that typical neurotoxic chemicals, i.e., acrylamide, ethylene oxide and methyl bromide, all inhibit creatine kinase (CK) activities in vitro (rat brain homogenate) and in vivo (rat and mouse). In this study, we have examined whether acrylamide impairs genetic expression of CK by utilizing RT-PCR and Western blotting to measure CK mRNA and CK protein level, respectively. As a result, we found no changes in mRNA of cytosolic CK (B subunit) and mitochondrial CK (ubiquitous form) or in protein level of cytosolic CK. Thus, apparent inhibition of CK activities by acrylamide in the brain is not caused by suppression of genetic expression of the enzyme.CK catalyzes the reaction ; ATP + creatine ←→ ADP + phosphocreatine. In view of the importance of maintaining constant energy (ATP) supply to the brain, inhibition of CK activities may be related to the neurotoxicity. Moreover, since the concept of "phosphocreatine shuttle" where CK plays a key role in both directions has been established, importance of the inhibition of CK activities by representative neurotoxic chemicals seem to be larger than before.

我们已经发现，典型的神经毒性化学物质，即，丙烯酰胺、环氧乙烷和溴甲烷在体外（大鼠脑匀浆）和体内（大鼠和小鼠）均抑制肌酸激酶（CK）活性。在本研究中，我们研究了丙烯酰胺是否损害CK的基因表达，利用RT-PCR和蛋白质印迹法分别测定CK mRNA和CK蛋白水平。结果发现，细胞质CK（B亚基）和线粒体CK（普遍存在的形式）的mRNA以及细胞质CK的蛋白水平没有变化。因此，脑内丙烯酰胺对肌酸激酶活性的明显抑制并不是由于抑制了该酶的基因表达，而是肌酸激酶催化了ATP +肌酸←→ ADP +磷酸肌酸的反应。鉴于维持脑能量（ATP）供应的重要性，CK活性的抑制可能与神经毒性有关。此外，由于“磷酸肌酸穿梭”的概念，其中CK在两个方向上都发挥了关键作用，CK活性的抑制的重要性，代表性的神经毒性化学品似乎比以前更大。

项目成果

Mastuoka, M., Igisu, H., Nakagawa, K., Katada, T., Nishina, H.: "Reguirement of SEK1 and MKK7 for CdCl_2-or HgCl_2-induced activation of c-Jun NH_2-terminal kinase in mouse embryonic stem cells"Toxicology Letters. (発表予定).

Mastuoka, M.、Igisu, H.、Nakakawa, K.、Katada, T.、Nishina, H.：“SEK1 和 MKK7 对 CdCl_2 或 HgCl_2 诱导的小鼠胚胎中 c-Jun NH_2 末端激酶激活的要求干细胞”毒理学快报。（待出版）。

Sugisawa, N., Matsuoka M., Okuno, T., Igisu H.: "Suppression of cadmium-induced JNK/p38 activation and HSP70 family gene expression by LL-Z1640-2 in NIH3T3 cells"Toxicology and Applied Pharmacology. (in press).

Sugisawa, N.、Matsuoka M.、Okuno, T.、Igisu H.：“LL-Z1640-2 在 NIH3T3 细胞中抑制镉诱导的 JNK/p38 激活和 HSP70 家族基因表达”毒理学和应用药理学。

Matsuoka M., Igisu H., Morimoto Y.: "Phosphorylation of p53 protein in A549 human pulmonary epithelial exposed to asbestos fibers"Environmental Health Perspectives. (in press).

Matsuoka M.、Igisu H.、Morimoto Y.：“暴露于石棉纤维的 A549 人肺上皮中 p53 蛋白的磷酸化”环境健康观点。

Matsuoka M., Igisu H.: "Effects of heavy metals on mitogen-activated protein kinase pathways"Journal of UOEH. 25・Suppl1. 209-216 (2003)

Matsuoka M.，Igisu H.：“重金属对丝裂原激活蛋白激酶途径的影响”UOEH 杂志 25·Suppl1（2003）。

Sugisawa, N., Matsuoka M., Okuno, T., Igisu H.: "Suppression of cadmium-induced JNK/p38 activation and HSP70 family gene expression by LL-Z1640-2 in NIH3T3 cells"Toxicology and Applied Pharmacology. 発表予定. (2004)

Sugisawa, N.、Matsuoka M.、Okuno, T.、Igisu H.：“LL-Z1640-2 在 NIH3T3 细胞中抑制镉诱导的 JNK/p38 激活和 HSP70 家族基因表达”毒理学和应用药理学。演讲（2004）