BACKGROUND Aging is defined as a biological and physical complex process that is characterized by the increase in susceptibility to diseases and eventually death. Aging may occur at different rates between and within species, especially or (it varies) among the long-lived ones. Here, we ask whether this diversity (e.g. aging phenotype) stems from genetic or environmental factors or as a combination between the two (epigenetics). Epigenetics play a central role in controlling changes in gene expression during aging. DNA methylation is the most abundant epigenetic modification among vertebrates and is essential to mammalian development. MATERIALS AND METHODS In this study, we utilized the HELPtag assay to identify five candidate genes that were significantly hyper- or hypo-methylated across four different age groups in mice. The candidate genes were annotated using ensemble and their expression was further tested in vitro using the murine RAW 264.7 cell line to examine the effect of three environmental stressors (UV radiation, Hypoxia and fasting) on their expression. RNA was extracted at different time points followed by cDNA synthesis. Changes in gene expression were evaluated using qRT-PCR. RESULTS We show that fasting and UV radiation reduced the viability of RAW264.7 cells. We also found a significant change in three candidate genes' expression levels during fasting (TOP2B, RNF13 and MRPL4). Furthermore, we found a significant change in the four candidate genes' expression levels following UVC treatment (TOP2B, RNF13, PKNOX1 and CREB5) and yet no changes were recorded in hypoxic conditions. CONCLUSION Our results suggest that the model we used was a fitting model for the assessment of environmental stressors on candidate gene expression. In addition, we established a cellular response to the environment via changes in gene expression.

中文翻译：

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环境应激因素对候选衰老相关基因的影响。

背景技术衰老被定义为生物和物理复杂过程，其特征在于对疾病的敏感性增加并最终导致死亡。物种之间和物种内部的衰老可能以不同的速率发生，特别是长寿命物种之间（或（不同））。在这里，我们问这种多样性（例如衰老表型）是源于遗传或环境因素，还是两者之间的结合（表观遗传学）。表观遗传学在控制衰老过程中基因表达的变化中起着核心作用。DNA甲基化是脊椎动物中最丰富的表观遗传修饰，对于哺乳动物的发育至关重要。材料和方法在这项研究中，我们利用HELPtag分析法鉴定了五个候选基因，这些候选基因在小鼠的四个不同年龄组中均显着高甲基化或低甲基化。使用集合对候选基因进行注释，并使用鼠RAW 264.7细胞系在体外进一步测试其表达，以检查三种环境胁迫（紫外线辐射，低氧和禁食）对其表达的影响。在不同的时间点提取RNA，然后合成cDNA。使用qRT-PCR评估基因表达的变化。结果我们显示禁食和紫外线辐射会降低RAW264.7细胞的活力。我们还发现禁食期间三个候选基因的表达水平（TOP2B，RNF13和MRPL4）发生了显着变化。此外，我们发现UVC处理后四个候选基因的表达水平发生了显着变化（TOP2B，RNF13，PKNOX1和CREB5），但在低氧条件下未发现任何变化。结论我们的结果表明我们使用的模型是用于评估候选基因表达的环境应激源的拟合模型。此外，我们通过基因表达的变化建立了对环境的细胞反应。