Yin Jiechen, Hong Xiang, Wang Jia, Li Weixi, Shi Yingchi, Wang Dayong, Liu Ran
Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China.
Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, China.
Ecotoxicol Environ Saf. 2023 Jan 1;249:114348. doi: 10.1016/j.ecoenv.2022.114348. Epub 2022 Dec 9.
Atrazine (ATR), a widely used triazine herbicide, is an environmental endocrine disruptor that can cause health problems. However, whether there are multi/trans-generational reproductive impacts of ATR have not been studied. Therefore, in this study, Caenorhabditis elegans was used as a preferable model organism to identify the multi/trans-generational reproductive toxicity of ATR. Only parental C.elegans (P0) were exposed to different concentrations (0.0004-40 mg/L) for 48 h and the subsequent offspring (F1-F5) were grown under ATR-free conditions and ATR conditions.The results showed that ATR exposure during P0 decreased fecundity, including a reduction in fertilized eggs, oocytes, and ovulation rate, delayed gonadal development, and decreased the relative area of gonad arm and germ cell number. Furthermore, continuous ATR exposure (P0-F5) causes a significant increase in reproductive toxicity in subsequent generations, although no significant toxicity occurred in the P0 generation after exposure to environmental-related concentrations, suggesting that ATR exposure might have cumulative effects. Likewise, parental exposure to ATR caused transgenerational toxicity impairments. Interestingly, only reproductive toxicity, not development toxicity, was transmitted to several generations (F1-F4), and the F2 generation showed the most notable changes. QRT-PCR results showed that genes expression related to DNA methylation 6 mA (damt-1, nmad-1) and histone H3 methylation (mes-4, met-2, set-25, set-2, and utx-1) can also be passed on to offspring. The function of H3K4 and H3K9 methylation were explored by using loss-of-function mutants for set-2, set-25, and met-2. Transmissible reproductive toxicity was absent in met-2(n4256), set-2(ok952), and set-25(n5021) mutants, which suggests that the histone methyltransferases H3K4 and H3K9 activity are indispensable for the transgenerational effect of ATR. Finally, the downstream genes of DNA methylation and histone H3 methylation were determined. ATR upregulated the expression of ZC317.7, hsp-6, and hsp-60. Mitochondrial stress in parental generation dependent transcription 6 mA modifiers may establish these epigenetic marks in progeny.
莠去津（ATR）是一种广泛使用的三嗪类除草剂，是一种可导致健康问题的环境内分泌干扰物。然而，ATR是否具有多代/跨代生殖影响尚未得到研究。因此，在本研究中，秀丽隐杆线虫被用作一种合适的模式生物来确定ATR的多代/跨代生殖毒性。仅将亲代秀丽隐杆线虫（P0）暴露于不同浓度（0.0004 - 40毫克/升）下48小时，随后的子代（F1 - F5）在无ATR条件和有ATR条件下生长。结果表明，P0期暴露于ATR会降低繁殖力，包括受精卵、卵母细胞数量减少以及排卵率降低，延迟性腺发育，并减少性腺臂的相对面积和生殖细胞数量。此外，连续暴露于ATR（P0 - F5）会导致后代的生殖毒性显著增加，尽管在暴露于环境相关浓度后P0代未出现明显毒性，这表明ATR暴露可能具有累积效应。同样，亲代暴露于ATR会导致跨代毒性损伤。有趣的是，只有生殖毒性而非发育毒性会传递给几代（F1 - F4），且F2代表现出最显著的变化。定量逆转录聚合酶链反应（QRT - PCR）结果表明，与DNA甲基化6mA（damt - 1、nmad - 1）和组蛋白H3甲基化（mes - 4、met - 2、set - 25、set - 2和utx - 1）相关的基因表达也可传递给后代。通过使用set - 2、set - 25和met - 2的功能缺失突变体来探究H3K4和H3K9甲基化的功能。在met - 2（n4256）、set - 2（ok952）和set - 25（n5021）突变体中不存在可传递的生殖毒性，这表明组蛋白甲基转移酶H3K4和H3K9的活性对于ATR的跨代效应是不可或缺的。最后，确定了DNA甲基化和组蛋白H3甲基化的下游基因。ATR上调了ZC317.7、hsp - 6和hsp - 60的表达。亲代线粒体应激依赖转录的6mA修饰因子可能在子代中建立这些表观遗传标记。
