Development of monitoring system of toxic chemicals base on the Nrf2-dependent detoxification pathway

用BHA饲喂NrfZ-LacZ小鼠3天后，观察到肠道、肝脏和腹腔巨噬细胞中LacZ活性的积聚。结果表明，NRF2-LacZ小鼠在检测食品或药品中的有毒化学物质方面是有用的。此外，我们还发现了Nrf2蛋白在转导后的积聚。分析Nrf2基因敲除小鼠Nrf2基因敲除小鼠对苯并[o]芘诱导的前胃肿瘤、柴油尾气诱导的肺组织增生和氧化DNA加合物形成以及对乙酰氨基酚诱导的肝脏毒性的易感性。这些结果表明，Nrf2基因敲除小鼠对致癌物和/或氧化应激高度敏感，它们将有助于检测食品或药品中的有毒化学物质。斑马鱼异源研究系统我们证明了基于Nrf2诱导的第二相解毒酶在鱼类中是保守的，并证明了使用斑马鱼系统监测致癌物的可能性。从而制备了与斑马鱼GSTpi基因转录调控区融合的GFP报告基因。在瞬时报告分析中，我们可以观察到亲电体在斑马鱼幼体中诱导GFP。我们现在正试图建立一个稳定的转基因斑马鱼品系，其中包含该构建物。

Analysis using Nrf2-LacZ miceAfter feeding NrfZ-LacZ mice with dietary BHA for 3 days, accumulation of LacZ activity was observed in intestine, liver and peritoneal macrophages. The result suggested that Nrf2-LacZ mice are useful for detecting toxic chemicals in foods or medicines. In addition, we found a posttranseriptional accumulation of Nrf2 protein in response to electrophiles.Analysis of Nrf2 knockout miceNrf2 knockout mice was susceptible to benzo[o]pyrene-induced neoplasia in the forestomach, diesel exhaust-induced hyperplasia and oxidative DNA adduct formation in the lung, and acetaminophen-induced hepatotoxicity. These results demonstrated that Nrf2 knockout mice are highly sensitive to carcinogen and/or oxidative stress, and that they will be useful for detecting toxic chemicals in foods or medicines.Zebrafish system for xenobiotic studiesWe showed that Nrf2-based induction of phase II detoxifying enzymes was conserved in fish and that a possibility of monitoring carcinogens using zebra fish system. Thus the GFP reporter construct fused to the transcriptional regulatory region of zebrafish GSTpi gene was prepared. In a transient reporter analysis, we could observed a GFP induction by electrophiles in zebra fish larvae. We are now trying to establish a stable transgenic zebrafish line which contains the construct.