Alcohol-induced epigenetic alterations to developmentally crucial genes regulating neural stemness and differentiation.
Alcohol-induced epigenetic alterations to developmentally crucial genes regulating neural stemness and differentiation.
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DOI：
10.1111/acer.12080
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发表时间：
2013-07
期刊：
影响因子：
--
通讯作者：
Golding MC
中科院分区：
文献类型：
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作者：
Veazey KJ;Carnahan MN;Muller D;Miranda RC;Golding MC
从使用各种模式生物的研究中，我们现在承认染色质结构的表观遗传变化提供了环境致畸剂和导致疾病的基因表达改变之间的合理联系。来自许多独立实验室的观察表明，乙醇有能力作为一种强大的表观遗传干扰剂，并可能破坏细胞分化的协调过程。在这项研究中，我们试图检查是否原代神经球培养条件下保持干细胞对酒精诱导的组蛋白密码的改变敏感。我们的研究集中在三甲基化组蛋白3赖氨酸4和三甲基化组蛋白3赖氨酸27上，因为这是调节干细胞维持和神经分化的两个最突出的翻译后组蛋白修饰。原代神经球培养物保持在促进干细胞状态的条件下，并用乙醇处理5天。使用定量RT-PCR和染色质免疫沉淀技术组合检查对照和乙醇处理的细胞提取物。我们发现，控制神经前体细胞的身份和分化过程的基因的调控区域表现出显着下降，在丰富的染色质标记检查。尽管染色质结构发生了广泛的变化，但只有一小部分基因（包括Dlx 2、Fabp 7、Nestin、Olig 2和Pax 6）显示出乙醇诱导的转录改变。出乎意料的是，所检查的大多数染色质修饰酶（包括多梳抑制复合物的成员）在表达和定位方面显示出最小的变化。只有编码Dnmt 1、Uhrf 1、Ehmt 1、Ash 2l、Wdr 5和Kdm 1b的转录物表现出显著差异。我们的研究结果表明，在体外作为干细胞维持的初级神经球容易受到酒精诱导的组蛋白编码扰动和表观遗传程序错误的影响。这些观察结果表明，染色质结构的改变可能是酒精致畸作用的一个重要组成部分，并朝着更好地理解FASD的发育起源的方向发展。
From studies using a diverse range of model organisms, we now acknowledge that epigenetic changes to chromatin structure provide a plausible link between environmental teratogens and alterations in gene expression leading to disease. Observations from a number of independent laboratories indicate ethanol has the capacity to act as a powerful epigenetic disruptor and potentially derail the coordinated processes of cellular differentiation. In this study, we sought to examine whether primary neurospheres cultured under conditions maintaining stemness were susceptible to alcohol-induced alterations of the histone code. We focused our studies on trimethylated histone 3 lysine 4 and trimethylated histone 3 lysine 27, as these are two of the most prominent post-translational histone modifications regulating stem cell maintenance and neural differentiation. Primary neurosphere cultures were maintained under conditions promoting the stem cell state and treated with ethanol for five days. Control and ethanol treated cellular extracts were examined using a combination of quantitative RT-PCR and chromatin immunoprecipitation techniques. We find that the regulatory regions of genes controlling both neural precursor cell identity and processes of differentiation exhibited significant declines in the enrichment of the chromatin marks examined. Despite these widespread changes in chromatin structure, only a small subset of genes including Dlx2, Fabp7, Nestin, Olig2, and Pax6 displayed ethanol induced alterations in transcription. Unexpectedly, the majority of chromatin modifying enzymes examined including members of the Polycomb Repressive Complex displayed minimal changes in expression and localization. Only transcripts encoding Dnmt1, Uhrf1, Ehmt1, Ash2l, Wdr5, and Kdm1b exhibited significant differences. Our results indicate primary neurospheres maintained as stem cells in vitro are susceptible to alcohol-induced perturbation of the histone code and errors in the epigenetic program. These observations indicate that alterations to chromatin structure may represent a crucial component of alcohol teratogenesis and progress towards a better understanding of the developmental origins of FASDs.