Epigenetic Landscape of Methamphetamine Use Disorder

The persistence of the addiction phenotype in methamphetamine use disorder (MUD) suggests the potential presence of epigenetic changes and potential structural adaptations that may drive the manifestations of MUD in humans. In the present review, we discuss the evidence that documents the fact that methamphetamine exposure can cause changes in epigenetic modifications, including histone acetylation and methylation, as well as DNA methylation and hydroxymethylation in a complex manner that need to be fully dissected. Nevertheless, our work has demonstrated the existence of correlations between behavioral changes and epigenetic alterations during methamphetamine self-administration. We found that prolonged methamphetamine self-administration and contingent footshocks resulted in rats with compulsive drug-taking and abstinent phenotypes. In addition, rats that reduce their methamphetamine intake in the presence of punishment showed increased DNA hydroxymethylation in genes encoding potassium channels in their nucleus accumbens. Moreover, altered DNA hydroxymethylation in those genes led to an increase in their mRNA expression. Additional studies revealed decreased mRNA expression of histone deacetylases associated with increased histone acetylation and induced gene expression in the dorsal striatum. These changes were associated with a reduction in methamphetamine intake in response to contingent footshocks. More research is necessary in order to further dissect how pharmacological or genetic manipulations of identified epigenetic alterations and expression of potassium channels can impact methamphetamine-taking behaviors or relapse to methamphetamine-taking after long periods of abstinence. Investigations that use discovery approaches, such as whole-genome sequencing after chromatin immunoprecipitation, should accelerate our efforts to develop epigenetic therapeutic approaches against MUD.     

Epigenetic targets of some toxicologically relevant metals: a review of the literature

The term epigenetics was coined in the context of developmental studies, but the meaning of the term has evolved over time. Epigenetic modulators of gene expression are now known to include DNA methylation, chromatin modifications and noncoding RNAs. The observation that epigenetic changes can be transmitted transgenerationally makes the science of epigenetics very relevant to the field of environmental and molecular toxicology. Heavy metals constitute an important class of environmental contaminants that have been known to influence gene expression directly by binding various metal response elements in the target gene promoters. Recent research suggests that metals can also influence gene expression through epigenetic mechanisms; this adds a new twist to the complexity of metal‐mediated gene expression. Here, we review recent studies that investigate the epigenetic, gene expression, and biological effects of various inorganic and organic forms of heavy metals, such as cadmium, arsenic, nickel, chromium, methylmercury, lead, copper and organotin compounds. Copyright © 2012 John Wiley & Sons, Ltd.     

Advances in skin gene therapy

Specific anatomical and biological properties make the skin a very interesting target organ for gene therapy approaches. Different cell types of the epidermis, such as keratinocytes, melanocytes, or dendritic cells, can be genetically modified to treat a broad spectrum of diseases, including genetically inherited skin disorders, tumour diseases, metabolic disorders and infectious diseases. The easy accessibility of skin suggests that different methods for gene delivery can be pursued, depending on the desired application. The approach used to deliver DNA to the skin will influence not only the efficiency of DNA delivery, but also the level and duration of transgene expression. Furthermore, the desired biological effect will also influence the decision of which gene transfer method is the best choice. Among the current challenges of cutaneous gene therapy are: optimising the efficiency of direct in vivo gene delivery; targeting specific epidermal cells, including keratinocyte stem cells; achieving sustained gene expression and regulating gene expression in vivo. This review summarises recent advances in the field of skin gene therapy and evaluates possible strategies to overcome obstacles and achieve successful clinical applications of skin gene therapy.     

Epigenetic changes in the rat livers induced by pyrazinamide treatment

Drug-induced liver injury, including drug-induced hepatotoxicity during the treatment of tuberculosis infection, is a major health problem with increasingly significant challenges to modern hepatology. Therefore, the assessment and monitoring of the hepatotoxicity of antituberculosis drugs for prevention of liver injury are great concerns during disease treatment. The recently emerged data showing the ability of toxicants, including pharmaceutical agents, to alter cellular epigenetic status, open a unique opportunity for early detection of drug hepatotoxicity. Here we report that treatment of male Wistar rats with antituberculosis drug pyrazinamide at doses of 250, 500 or 1000 mg/kg/day body weight for 45 days leads to an early and sustained decrease in cytosine DNA methylation, progressive hypomethylation of long interspersed nucleotide elements (LINE-1), and aberrant promoter hypermethylation of placental form glutathione-S-transferase (GSTP) and p16(INK4A) genes in livers of pyrazinamide-treated rats, while serum levels of bilirubin and activity of aminotransferases changed modestly. The early occurrence of these epigenetic alterations and their association with progression of liver injury specific pathological changes indicate that alterations in DNA methylation may be useful predictive markers for the assessment of drug hepatotoxicity.     

胎兔与成兔皮肤瘢痕基因差异表达的分析

目的 探讨胎兔及成兔皮肤瘢痕基因表达变化的特征及其可能的生物学意义.方法 建立动物模型,收集胎兔及成兔皮肤愈合处的皮肤组织,用基因芯片技术检测胎兔及成兔皮肤瘢痕的基因表达变化规律.结果 基因芯片高通量地揭示了胎兔及成兔皮肤瘢痕的基因表达变化的信息,差异表达基因有117个,其中下调的基因有28个,上调的基因有89个,涉及十大类基因.结论 胎兔及成兔皮肤瘢痕的基因图谱存在差别,这些基因可能参与了瘢痕的形成过程.     

长非编码RNA与其他表观遗传学的相互调控与神经系统疾病

开始受到人们关注的长非编码RNA(lncRNA)是一类长度超过200个核苷酸RNA分子。lncRNA虽无编码蛋白质的功能,但其功能异常与神经系统疾病密切相关。作为新发现的表观遗传调控形式,lncRNA可通过与近年来研究较多的其他表观遗传学调控(包括DNA甲基化、组蛋白修饰、基因组印记、染色质重构和RNA干扰等)的相互作用参与调控和维持神经系统功能的稳态。该文就lncRNA与其他多种表观遗传学的相互调控与神经系统疾病研究的新进展进行综述,有助于深入探寻lncRNA介导神经系统疾病的发病机制。     

长期低剂量甲醛染毒对永生化人支气管上皮细胞16HBE部分癌症相关基因启动子区甲基化的影响

目的探讨低剂量甲醛长期染毒对永生化人支气管上皮细胞16HBE癌症相关基因启动子区甲基化水平的影响。方法 16HBE细胞每周染毒甲醛10μmol·L-1 24h,连续24周,分别于染毒3,6,9,12,15,18,21和24周提取RNA或DNA,应用DNA甲基化相关酶消化结合荧光定量PCR的方法观察24个癌症相关基因启动子区甲基化水平的变化;应用荧光定量PCR的方法观察染毒对亚甲基四氢叶酸还原酶基因(MTHFR)和成对盒基因(PAX5)基因表达的时间-效应关系。结果与正常对照组16HBE细胞相比,甲醛染毒细胞4个基因甲基化水平显著改变,2个基因甲基化程度升高,2个基因甲基化程度降低;而在阳性对照人非小细胞癌上皮细胞A549细胞中有9个基因甲基化水平发生显著变化,其中3个基因甲基化水平升高,6个基因甲基化水平降低;甲醛染毒16HBE细胞和A549细胞MTHFR基因均发生高甲基化改变,PAX5基因均出现低甲基化改变。与正常对照组相比,甲醛染毒24周的细胞中,MTHFR基因启动子区甲基化水平升高,非甲基化DNA含量降低58.2%,而PAX5基因启动子区甲基化水平降低,非甲基化DNA含量升高27.1%;随着甲醛染毒时间延长,MTHFR基因表达逐渐降低,而PAX5基因表达逐渐升高。结论低剂量甲醛长期染毒可以使MTHFR基因和PAX5基因启动子区甲基化水平异常,进而引起基因表达水平改变。     

芥子气诱导小鼠耳廓皮肤差异蛋白的鉴定

目的通过芥子气染毒后小鼠耳廓皮肤蛋白质组的改变,探索芥子气皮肤损伤的分子机制。方法5μL(160g·L-1)芥子气经小鼠耳廓内侧皮肤染毒,于染毒后6和24h制备蛋白样品,采用双向电泳技术分离蛋白样品,ImageMaster5.01软件处理双向电泳图谱,基质辅助激光解吸附飞行时间质谱分析差异蛋白点的肽质量指纹谱。结果正常对照组、染毒后6和24h组分别检测到1442,1451和1158个蛋白质点,各组蛋白质的匹配百分比为64.5%~82.0%。共鉴定了15个差异蛋白,主要与过氧化应激、细胞凋亡及能量代谢等相关。染毒后的表达上升的蛋白有载脂蛋白A-I和前白蛋白;表达下降的蛋白有过氧化物氧还酶6、超氧化物歧化酶、羰基还原酶3、肌动蛋白、谷胱甘肽S-转移酶Mu2和Δ3,5,Δ2,4-二烯酰辅酶A异构酶;6h时表达上升,24h时下降的蛋白有丙糖磷酸异构酶、脂肪酸结合蛋白、微丝结合蛋白-1、肌动蛋白解聚因子和蛋白突触结合蛋白样蛋白-3的剪接同工型4。6h表达下降,24h表达上升的蛋白是半胱氨酸天冬氨酸蛋白酶抑制剂B。钙粒蛋白B仅出现于染毒后6h组,对照组与染毒后24h组没有出现。结论芥子气染毒能诱导小鼠皮肤蛋白表达谱的改变。     

基于mRNA和miRNA表达谱及基因甲基化谱的直肠腺癌发生相关分子标志物的研究

摘要： 目的 通过综合分析高通量miRNA/mRNA的表达数据及DNA甲基化数据， 研究直肠腺癌 （READ） 潜在的发病机制。方法 从癌症基因组图谱 （TCGA） 数据库中下载miRNA/mRNA表达数据及DNA甲基化数据。利用 DESeq2软件包筛选差异表达的miRNA （DEmiRNAs）、 mRNA （DEmRNAs）， 利用COHCAP软件包筛选差异甲基化位点（DMSs）。采用生物信息学方法分别构建DEmiRNAs与DEmRNAs的调控网络和DNA甲基化与DEmRNAs调控网络，获得DEmiRNAs与DEmRNAs负调控关系对 （DEmiRNA-DEmRNA）， 以及DNA甲基化与DEmRNAs的负调控关系对（DNAmethylation-DEmRNA）。利用KEGG分析得到异常甲基化的DEmRNAs富集的通路。最后通过实时定量聚合酶链式反应 （qRT-PCR） 验证其中差异显著的DEmRNAs的表达水平。结果 在数据中筛选到了1 192个DEmRNAs， 27个DEmiRNAs， 通过靶基因筛选， 获得1 987个miRNA-mRNA调控关系对。得到446个甲基化异常的基因， 6 403 个异常甲基化的CpG位点。通过对446个异常甲基化基因和668个DEmRNAs的关联性分析， 发现50个DEmRNAs （39个下调和11个上调） 伴有高甲基化， 同时受到DEmiRNAs的负调控。这50个DEmRNAs显著富集于cAMP、 昼夜节律和谷氨酸等信号通路。qRT-PCR结果显示DEmRNAs表达结果与预测结果一致。结论 受到DEmiRNAs负调控的7个高甲基化基因 （SORCS1、 PDZRN4、 LONRF2、 CNGA3、 HAND2、 RSPO2和GNAO1） 可能促进了READ的发生。     

表观遗传修饰在胚胎发育过程中的调控作用研究进展

表观遗传修饰是生命现象中普遍存在的一类基因调控方式,对维持哺乳动物正常生命活动至关重要。表观遗传修饰方式主要包括DNA甲基化、组蛋白乙酰化和组蛋白甲基化修饰,通常协同调控基因表达,且易受到营养和外源物等多种环境因素的影响,在胚胎正常发育中扮演重要角色。胚胎时期表观遗传修饰异常可能诱导胚胎甚至成年后多种疾病的发生。本文重点从DNA甲基化、组蛋白乙酰化和组蛋白甲基化修饰方面,综述表观遗传修饰在基因调控、胚胎发育过程中的作用及其可能的临床意义。     

Gene Expression During Imidacloprid-Induced Hormesis in Green Peach Aphid

Imidacloprid-induced hormesis in the form of stimulated reproduction has previously been reported in green peach aphid, Myzus persicae. Changes in gene expression accompanying this hormetic response have not been previously investigated. In this study, expression of stress response (Hsp60), dispersal (OSD, TOL and ANT), and developmental (FPPS I) genes were examined for two generations during imidacloprid-induced reproductive stimulation in M. persicae. Global DNA methylation was also measured to test the hypothesis that changes in gene expression are heritable. At hormetic concentrations, down-regulation of Hsp60 was followed by up-regulation of this gene in the subsequent generation. Likewise, expression of dispersal-related genes and FPPS I varied with concentration, life stage, and generation. These results indicate that reproductive hormesis in M. persicae is accompanied by a complex transgenerational pattern of up- and down-regulation of genes that likely reflects trade-offs in gene expression and related physiological processes during the phenotypic dose-response. Moreover, DNA methylation in second generation M. persicae occurred at higher doses than in first-generation aphids, suggesting that heritable adaptability to low doses of the stressor might have occurred.     

Epigenetic influences of low-dose bisphenol A in primary human breast epithelial cells

Substantial evidence indicates that exposure to bisphenol A (BPA) during early development may increase breast cancer risk later in life. The changes may persist into puberty and adulthood, suggesting an epigenetic process being imposed in differentiated breast epithelial cells. The molecular mechanisms by which early memory of BPA exposure is imprinted in breast progenitor cells and then passed onto their epithelial progeny are not well understood. The aim of this study was to examine epigenetic changes in breast epithelial cells treated with low-dose BPA. We also investigated the effect of BPA on the ERα signaling pathway and global gene expression profiles. Compared to control cells, nuclear internalization of ERα was observed in epithelial cells preexposed to BPA. We identified 170 genes with similar expression changes in response to BPA. Functional analysis confirms that gene suppression was mediated in part through an ERα-dependent pathway. As a result of exposure to BPA or other estrogen-like chemicals, the expression of lysosomal-associated membrane protein 3 (LAMP3) became epigenetically silenced in breast epithelial cells. Furthermore, increased DNA methylation in the LAMP3 CpG island was this repressive mark preferentially occurred in ERα-positive breast tumors. These results suggest that the in vitro system developed in our laboratory is a valuable tool for exposure studies of BPA and other xenoestrogens in human cells. Individual and geographical differences may contribute to altered patterns of gene expression and DNA methylation in susceptible loci. Combination of our exposure model with epigenetic analysis and other biochemical assays can give insight into the heritable effect of low-dose BPA in human cells.     

Epigenetic dimension of oxygen radical injury in spermatogonial epithelial cells

The present work reports a direct role of mitochondrial oxidative stress induced aberrant chromatin regulation, as a central phenomenon, to perturbed genomic integrity in the testicular milieu. Oxygen-radical injury following N-succinimidyl N-methylcarbamate treatment in mouse spermatogonial epithelial (GC-1 spg) cells induced functional derailment of mitochondrial machinery. Mitophagy resulted in marked inhibition of mitochondrial respiration and reduced mtDNA copy number. Impaired cell cycle progression along with altered H3K9me1, H4K20me3, H3, AcH3 and uH2A histone modifications were observed in the treated cells. Dense heterochromatin foci and aberrant expression of HP1α in nuclei of treated cells implied onset of senescence associated secretory phenotype mediated through nuclear accumulation of NF-κB. Neoplastic nature of daughter clones, emerged from senescent mother phenotypes was confirmed by cytogenetic instability, aberrant let-7a and let-7b miRNA expression and anchorage independent growth. Together, our results provide the first insights of redox-dependent epigenomic imbalance in spermatogonia, a previously unknown molecular paradigm.