Mechanism of Generation of Reactive Oxygen Species from Mitochondria by Nuclear Signal

活性氧簇(ROS)似乎是各种疾病和致病机制的诱因，如衰老、神经退行性疾病，即阿尔茨海默病、帕金森氏病等。JBC 1998)，我们研究了ROS与辐射、蓝光照射、缺血再灌注、化疗药物(博莱霉素和顺铂)引起的细胞凋亡的关系。在每一次实验中，我们都证实了ROS、脂质过氧化和细胞凋亡之间的关系。在本研究中，我们进一步利用DNA芯片研究了线粒体DNA缺失细胞(Rho0细胞)的核基因组激活，发现在Rho0细胞中2236个核基因中有402个基因发生了变化，提示线粒体和细胞核之间可能存在串扰信使。为了测试P53和HSP70在串音信使中的可能作用，我们通过这些RNAi抑制了mRNA的表达水平，并研究了线粒体产生ROS的变化。转染MnSOD RNAi载体后ROS明显增加，而P53和HSP70 RNAi载体对ROS无明显影响，提示P53和HSP70不是串扰信使。

Reactive oxygen species (ROS) seem to be an inducer of various diseases and pathogenesis such as aging, neuro-degenerative diseases, i.e., Alzheimer's disease, Parkinson's disease etc. Since we have reported the first evidence that mitochondrial generation of ROS controls apoptosis (Majima et al. JBC 1998), we have investigated the relationship between ROS and apoptosis, caused by radiation, blue light exposure, ischemia reperfusion, chemotherapeutic agent treatments (bleomycin and cis-platinum). In every experiments tested, we have confirmed the relationship among ROS, lipid peroxidation and apoptosis.In this study, we further investigated nuclear genome activation in mitochondrial DNA lacking cells (Rho0 cells) by DNA microarray, and found out that 402 genes out of 2236 nuclear genes were changed in Rho0 cells, suggesting a possible cross-talk messengers between mitochondria and nucleus. To test a possible role of p53 and hsp70 on the cross-talk messenger, we suppressed mRNA expression level by these RNAi, and studied change of ROS generation from mitochondria. A positive increase in ROS by transfection of MnSOD RNAi vectors was found, while no change of ROS by transfection of p53 or hsp70 RNAi vectors were revealed, suggesting p53 and HSP70 are not candidate of the cross-talk messenger.