The study of modulating effects on X-ray induced cell mutability by chaperons and autophagy

本研究旨在探讨分子伴侣和自噬在辐射致突变抑制生理功能中的作用。(1)我们以前报道过，热休克蛋白27参与紫外线照射后的细胞DNA修复功能。在本研究中，annexinII被确定为一个候选基因的HSP 27相互作用蛋白，并建议参与细胞的UV抗性的克隆形成试验，使用siRNA的annexinII mRNA。(2)我们还尝试蛋白质组学研究，以阐明辐射相关基因。利用X射线照射的核细胞提取物，我们发现了一些候选基因。糖酵解酶基因之一的醛缩酶A被认为与细胞的X射线抗性有关。(3)为了进一步研究自噬在辐射应答中的参与，使用HSP 27抑制性细胞系分析了自噬标志蛋白之一LC 3的表达水平。我们没有发现任何差异的LC3表达水平之间的HSP 27抑制和对照细胞，虽然增加水平的LC3血清饥饿后观察到。(4)在人体中，氧化应激条件预期在调节辐射反应中发挥作用。因此，进行了通过评价血清氢过氧化物监测氧化应激的试验。类风湿性关节炎和糖尿病患者的血清氢过氧化物水平高于健康志愿者。因此，辐射敏感性是否受分子伴侣代谢和氧化条件的共同调控将是一个有趣的问题。

The present work is designed to investigate the role of chaperons and autophagy on the suppressive physiological functions for radiation-induced mutagenicity in human. (1) We previously reported that HSP27 is involved in cellular DNA-repair functions after UV irradiation. In the present study, annexinII was identified as a candidate gene for the HSP27 interacting protein, and suggested to be involved in cellular UV resistance by the colony forming assay using siRNA for annexinII mRNA. (2) We also tried proteomic studies for elucidation of radiation responsible genes. Using X-ray irradiated-nuclear cell extracts, we found some candidate genes. Aldolase A, one of genes for glycolytic enzyme proteins, was suggested to be involved in cellular X-ray resistance. (3) To moreover examine the involvement of autophagy in radiation response, expression levels of LC3, one of autophagy marker proteins, were analyzed using HSP27-suppressive cell lines. We could not find any difference of LC3 expression levels between HSP27-suppressive and control cells, although increased levels of LC3 was observed after serum starvation. (4) In human body oxidative stress conditions are expected to play roles on modulation of radiation response. Therefore, the test to monitor the oxidative stress by evaluating serum hydroperoxide was carried out. Amounts of serum hydroperoxide showed higher levels in patients, such as rheumatoid arthritis and diabetes mellitus, than healthy volunteers. Thus, it will be an intriguing problem whether radiation susceptibility in human is regulated by combination of chaperones metabolism with oxidative conditions.