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

本研究旨在探讨伴随子和自噬在人体辐射诱变抑制生理功能中的作用。(1)我们之前报道了HSP27参与紫外线照射后细胞dna修复功能。在本研究中，annexinII被确定为HSP27相互作用蛋白的候选基因，并通过siRNA对annexinII mRNA进行集落形成试验，提示其参与细胞抗紫外线。(2)我们还尝试了蛋白质组学研究来阐明辐射相关基因。利用x射线辐照的核细胞提取物，我们发现了一些候选基因。醛缩酶A是糖酵解酶蛋白的基因之一，被认为与细胞x射线抗性有关。(3)为了进一步研究自噬在辐射应答中的作用，我们利用抑制hsp27的细胞系分析了自噬标记蛋白之一LC3的表达水平。我们没有发现hsp27抑制细胞和对照细胞之间LC3表达水平有任何差异，尽管血清饥饿后LC3表达水平升高。(4)人体氧化应激条件可能在辐射反应中起调节作用。因此，通过测定血清过氧化氢来监测氧化应激。类风湿关节炎和糖尿病患者的血清过氧化氢水平高于健康志愿者。因此，人体的辐射易感性是否受到伴侣蛋白代谢与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.