DNA甲基化调控炎症反应干预As斑块稳定性的研究进展

动脉粥样硬化(As)斑块破裂是导致急性心脑血管事件发生的首要原因。既往对斑块破裂的基础研究多集中于细胞和分子水平,从表观遗传学角度阐述的研究较少。DNA甲基化作为表观遗传学修饰的主要方式之一,可在不改变基因核苷酸序列的情况下影响基因的表达。综合目前研究来看,炎症反应在斑块破裂过程中起关键性作用,而DNA甲基化对炎症反应又起重要的调控作用。因此,改变DNA甲基化状态来调控炎症反应干预As斑块稳定性,有望成为防治As等心脑血管疾病的有效途径之一。本文主要围绕与As炎症反应密切相关的几种炎症免疫细胞及炎症因子等方面,对近年来DNA甲基化调控炎症反应干预As斑块稳定性的研究进展作一综述。     

DNA羟甲基化调控动脉粥样硬化的研究进展

DNA羟甲基化作为一种表观遗传学修饰,对基因的表达调控起到了重要作用。近年来,越来越多的研究发现在心血管疾病中可见5-羟甲基胞嘧啶(5-hydroxymethylcytosine, 5hmC)和染色体10/11易位(ten-eleven translocation,TET)家族蛋白的异常改变,提示这些心血管疾病与DNA羟甲基化的调控密切相关。DNA羟甲基化水平与动脉粥样硬化常见的危险因素如衰老、性别、高血压和吸烟存在一定关联,并且和动脉粥样硬化发生过程中所涉及的免疫炎症反应以及内皮细胞和血管平滑肌细胞的功能相关。本文综述了DNA羟甲基化和TET家族蛋白对于动脉粥样硬化的作用机制及研究现状,以期为动脉粥样硬化的发生发展及诊断治疗提供表观遗传学方面的研究思路。     

DNA甲基化与动脉粥样硬化

DNA甲基化是一种重要的表观遗传调控方式,可在转录前水平调节基因的表达.近年来的研究表明,动脉粥样硬化的发生发展与DNA甲基化密切相关. 对DNA甲基化模式改变在动脉粥样硬化发病的相关机制做深入研究,可能为动脉粥样硬化的诊治提供一种新的途径.本文将从基因组低甲基化、相关基因异常甲基化以及动脉粥样硬化危险因素的DNA甲基化等方面重点阐述DNA甲基化与动脉粥样硬化的关系.     

脂滴包被蛋白2在动脉粥样硬化中的作用

动脉粥样硬化性心血管疾病严重威胁着人类生命健康,其中脂质代谢异常和炎症反应是其重要的发病机制。脂滴是细胞内储存脂质的一种亚细胞器,其表面存在多种脂滴包被蛋白,参与调控脂质动态平衡。脂滴包被蛋白2(Plin2)作为脂滴包被蛋白的一种,在脂质代谢的调节、脂肪酸的氧化及炎症反应等多种生理功能中发挥重要作用。近年来,越来越多的研究发现Plin2在动脉粥样硬化的发生发展中扮演着重要的角色。因此,本文主要综述Plin2在胆固醇代谢、脂质合成、自噬和炎症反应等过程中发挥的作用,进一步阐述其与动脉粥样硬化之间的关系。     

DNA甲基化在克罗恩病中的调控作用

克罗恩病(Crohn's disease, CD)是一种慢性、反复发作的多病因肠道异质性疾病。在此过程中,CD可显著改变肠道黏膜组织形态及炎症相关基因的甲基化水平,并可影响血细胞炎症基因的甲基化修饰,进而调控相关基因的表达并诱导CD相关的炎症、黏膜损伤等病理反应,这也意味着特定位点的DNA甲基化可作为CD诊疗的潜在分子靶标。该文将综合阐述CD与DNA甲基化修饰的相关性及DNA甲基化作为CD诊断分子标记的可行性。     

基于生物芯片探讨高脂饮食对动脉粥样硬化小鼠基因组DNA甲基化的影响

目的:采用DNA甲基化芯片技术探讨高脂饮食对Apo E-/-小鼠动脉粥样硬化模型全基因组DNA甲基化的影响。方法:30只雄性Apo E-/-小鼠随机分为正常组与高脂组,每组15只,正常组给予正常饲料喂养,高脂组给予高脂饲料喂养。16周后,测其血脂、血清同型半胱氨酸水平(Hcy)水平、血清DNA甲基化与血清DNA甲基化转移酶(DNMTs)水平;采用DNA甲基化芯片检测两组小鼠主动脉组织全基因组甲基化情况。结果:与正常组相比,高脂组小鼠血清CHOL、TG、LDL-C均显著升高,HDL-C显著下降;血清DNA甲基化水平与血清DNA甲基化转移酶(DNMTs)水平均显著升高。甲基化芯片结果显示:与正常组相比,高脂组主动脉全基因组中共有875个基因甲基化发生改变,差异具有统计学意义(P0.05),其中高甲基化基因数目496,占总数56.69%;低甲基化基因数目379,占总数的43.31%。结论:高脂饲料可升高主动脉基因组甲基化水平,降低基因组的表达,可能是Apo E-/-小鼠容易形成动脉粥样硬化的机制之一。     

睾酮缺乏对高脂诱导小型猪内脏脂肪组织DNA甲基化的影响

为探讨DNA甲基化在睾酮缺乏促进高脂饮食诱导的小型猪肥胖中的作用,本研究采用甲基化DNA免疫共沉淀测序(MeDIP-Seq)技术分析高脂饲喂的不去势、去势和去势+睾酮3组小型猪内脏脂肪组织DNA甲基化差异,对筛选出的差异甲基化基因进行注释和功能富集分析,并运用RT-qPCR技术检测差异甲基化基因的表达.结果 表明,不去势、去势和去势+睾酮3组样本在基因组上的甲基化分布情况相似,即Genebody区的甲基化水平高于3'UTR和5'UTR区.另外,在去势Vs.不去势和去势Vs.去势+睾酮两组样本中分别筛选得到2839个和2510个差异甲基化基因,这些基因主要富集在脂肪细胞因子转导、抗原处理以及呈递、脂肪酸代谢和氨基酸代谢等通路.睾酮缺乏导致高脂饲喂小型猪内脏脂肪组织LEP以及NCF1内含子区甲基化和SLC-27A1启动子区甲基化水平升高,并且LEP和NCF1 mRNA表达与甲基化呈正相关,而SLC27A1 mR-NA表达与甲基化呈负相关.本研究推测,睾酮缺乏可能通过影响脂质代谢和炎症反应等多个途径基因DNA甲基化参与调控脂肪沉积和肥胖发生.     

细胞焦亡在动脉粥样硬化中的作用CSCD

动脉粥样硬化是脂代谢紊乱和炎症共同作用的结果,在动脉粥样硬化中可以观察到细胞死亡,并且在动脉粥样硬化病变的发生发展中起重要作用。炎症是先天免疫的主要反应,被认为是动脉粥样硬化的启动者和驱动者。尽管大量研究揭示了凋亡、自噬和细胞坏死在动脉粥样硬化中的作用,但参与动脉粥样硬化的细胞死亡机制仍然在很大程度上是未知的。细胞焦亡是新近发现的一种程序性细胞死亡方式,其通过促使炎性因子释放而参与动脉粥样硬化的形成与进展,并与斑块的稳定性密切相关。本文就细胞焦亡在动脉粥样硬化中的作用作一综述。     

细胞焦亡在动脉粥样硬化中的作用

动脉粥样硬化是脂代谢紊乱和炎症共同作用的结果,在动脉粥样硬化中可以观察到细胞死亡,并且在动脉粥样硬化病变的发生发展中起重要作用。炎症是先天免疫的主要反应,被认为是动脉粥样硬化的启动者和驱动者。尽管大量研究揭示了凋亡、自噬和细胞坏死在动脉粥样硬化中的作用,但参与动脉粥样硬化的细胞死亡机制仍然在很大程度上是未知的。细胞焦亡是新近发现的一种程序性细胞死亡方式,其通过促使炎性因子释放而参与动脉粥样硬化的形成与进展,并与斑块的稳定性密切相关。本文就细胞焦亡在动脉粥样硬化中的作用作一综述。     

DNA甲基化与炎症反应相互作用的研究进展

DNA甲基化转移酶催化基因CpG岛并选择性添加甲基,引起DNA甲基化,使某些区域DNA构象变化,阻止转录因子与启动子结合,并进而抑制基因转录。DNA甲基化与炎症反应密切相关。本文总结DNA甲基化对炎性因子和炎性信号通路的调控机理,以及炎性因子对DNA甲基化转移酶的活化机制。概述炎症反应中DNA甲基化尚待解决的问题,展望DNA甲基化在揭示人类疾病机制,新型药物开发等方面的发展前景。     

Rev-erb alpha gives a time cue to metabolism

Normal physiological processes are under control of circadian rhythms. Moreover, certain pathological events, such as cardiovascular accidents (myocardial infarction, stroke) occur more frequently at specific times of the day. Recent observations demonstrate a causal relationship between alterations in circadian rhythmicity and metabolic disorders. Disruption of clock genes results in dyslipidemia, insulin resistance and obesity, all predisposing to atherosclerosis. The nuclear receptor Rev-erb alpha is part of the clock circuitry and plays an important role in keeping proper timing of the clock. Rev-erb alpha also regulates lipid metabolism, adipogenesis and vascular inflammation. Interestingly, Rev-erb alpha also cross-talks with several other nuclear receptors involved in energy homeostasis. Therefore Rev-erb alpha may serve to couple metabolic and circadian signals.     

DNA demethylation of promoter region orchestrates SPI-1-induced ADAMTS-5 expression in articular cartilage of osteoarthritis mice

Osteoarthritis (OA) is one of the most prevalent joint diseases in aged people and characterized by articular cartilage degeneration, synovial inflammation, and abnormal bone remodeling. Recent advances in OA research have clearly shown that OA development is associated with aberrant DNA methylation status of many OA-related genes. As one of most important cartilage degrading proteases in OA, a disintegrin and metalloproteinase with thrombospondin motifs subtype 5 (ADAMTS-5) is activated to mediate cartilage degradation in human OA and experimental murine OA models. The pathological factors and signaling pathways mediating ADAMTS-5 activation during OA development are not well defined and have been a focus of intense research. ADAMTS-5 promoter is featured by CpG islands. So far there have been no reports concerning the DNA methylation status in ADAMTS-5 promoter during OA development. In this study, we sought to investigate DNA methylation status in ADAMTS-5 promoter, the role of DNA methylation in ADAMTS-5 activation in OA, and the underlying mechanisms. The potential for anti-OA intervention therapy which is based on modulating DNA methylation is also explored. Our results showed that DNA methyltransferases 1 (Dnmt1) downregulation-associated ADAMTS-5 promoter demethylation played an important role in ADAMTS-5 activation in OA, which facilitated SPI-1 binding on ADAMTS-5 promoter to activate ADAMTS-5 expression. More importantly, OA pathological phenotype of mice was alleviated in response to Dnmt1-induced DNA methylation of ADAMTS-5 promoter. Our study will benefit not only for deeper insights into the functional role and regulation mechanisms of ADAMTS-5 in OA, but also for the discovery of disease-modifying OA drugs on the basis of ADAMTS-5 via modulating DNA methylation status.     

Integrated Analysis of Microarray Data of Atherosclerotic Plaques: Modulation of the Ubiquitin-Proteasome System

Atherosclerosis is a typical complex multi-factorial disease and many molecules at different levels and pathways were involved in its development. Some studies have investigated the dysregulation in atherosclerosis at mRNA, miRNA or DNA methylation level, respectively. However, to our knowledge, the studies that integrated these data and revealed the abnormal networks of atherosclerosis have not been reported. Using microarray technology, we analyzed the omics data in atherosclerosis at mRNA, miRNA and DNA methylation levels. Our results demonstrated that the global DNA methylation and expression of miRNA/mRNA were significantly decreased in atherosclerotic plaque than in normal vascular tissue. The interaction network constructed using the integrative data revealed many genes, cellular processes and signaling pathways which were widely considered to play crucial roles in atherosclerosis and also revealed some genes, miRNAs or signaling pathways which have not been investigated in atherosclerosis until now (e.g. miR-519d and SNTB2). Moreover, the overall protein ubiquitination in atherosclerotic plaque was significantly increased. The proteasome activity was increased early but decreased in advanced atherosclerosis. Our study revealed many classic and novel genes and miRNAs involved in atherosclerosis and indicated the effects of ubiquitin-proteasome system on atherosclerosis might be closely related to the course of atherosclerosis. However, the efficacy of proteasome inhibitors in the treatment of atherosclerosis still needs more research.     

Polymerase chain reaction-based methods of DNA methylation analysis

DNA methylation is the main epigenetic modification in humans, and changes in methylation patterns play an important role in tumorigenesis. Hypermethylation of normally unmethylated CpG islands in the promoter regions often occurs in important tumor suppressor genes, DNA repair genes, and metastasis inhibitor genes. The changes of methylation status of various gene promoters seem to be a common feature of malignant cells and these changes can occur early in the progression process. Therefore detection of aberrant promoter hypermethylation of cancer-related genes may be useful for cancer diagnosis or detection of cancer recurrence. The purpose of this review is to provide a summary of the most commonly used techniques for the study of DNA methylation. Current scientific literature involving methylation detection methods was reviewed with an emphasis on polymerase chain reaction (PCR)-based detection methods. The current methodologies may be broadly classed into PCR-based methylation assays and non-PCR-based methylation assays. The problems and advantages of the different methods for detecting aberrant methylation are discussed. As the number of genes known to be hypermethylated in cancer is growing, the detection of aberrant promoter region methylation will be a promising approach for using DNA-based markers for the early detection of human cancers. Many techniques, especially PCR-based methylation assay techniques, make it practical to use these new methylation biomarkers in early cancer diagnosis.     

DNA甲基化与脂肪组织生长发育

DNA甲基化作为一种重要的表观遗传学修饰方式,在维持正常细胞功能、遗传印记、胚胎发育以及人类肿瘤发生中起着重要作用。DNA甲基化最重要的作用是调控基因表达,它是细胞调控基因表达的重要表观遗传机制之一。近年来的研究发现,DNA甲基化在脂肪组织生长发育以及肥胖症发生过程中发挥着重要作用。DNA甲基化通过调控脂肪细胞分化转录因子、转录辅助因子以及其他脂肪代谢相关基因的表达,从而调控脂肪组织的生长发育。该文综述了脂肪组织生长发育过程中DNA甲基化的最新研究进展,探讨了脂肪组织DNA甲基化的研究趋势和未来发展方向。     

Epigenetic Regulatory Effect of Exercise on Glutathione Peroxidase 1 Expression in the Skeletal Muscle of Severely Dyslipidemic Mice

Exercise is an effective approach for primary and secondary prevention of cardiovascular diseases (CVD) and loss of muscular mass and function. Its benefits are widely documented but incompletely characterized. It has been reported that exercise can induce changes in the expression of antioxidant enzymes including Sod2, Trx1, Prdx3 and Gpx1 and limits the rise in oxidative stress commonly associated with CVD. These enzymes can be subjected to epigenetic regulation, such as DNA methylation, in response to environmental cues. The aim of our study was to determine whether in the early stages of atherogenesis, in young severely dyslipidemic mice lacking LDL receptors and overexpressing human ApoB100 (LDLR^-/-; hApoB^+/+), exercise regulates differentially the expression of antioxidant enzymes by DNA methylation in the skeletal muscles that consume high levels of oxygen and thus generate high levels of reactive oxygen species. Expression of Sod2, Txr1, Prdx3 and Gpx1 was altered by 3 months of exercise and/or severe dyslipidemia in 6-mo dyslipidemic mice. Of these genes, only Gpx1 exhibited changes in DNA methylation associated with dyslipidemia and exercise: we observed both increased DNA methylation with dyslipidemia and a transient decrease in DNA methylation with exercise. These epigenetic alterations are found in the second exon of the Gpx1 gene and occur alongside with inverse changes in mRNA expression. Inhibition of expression by methylation of this specific locus was confirmed in vitro. In conclusion, Gpx1 expression in the mouse skeletal muscle can be altered by both exercise and dyslipidemia through changes in DNA methylation, leading to a fine regulation of free radical metabolism.     

Promoter methylation and functional variants in arachidonate 5-lipoxygenase and forkhead box protein O1 genes associated with coronary artery disease

Coronary artery disease (CAD) is a multifactorial chronic inflammatory disease, which is the most common form of heart disease. This is one of the main causes of death in the United States. Inflammation is one of the key drivers of atherosclerotic plaque development. Forkhead box protein O1 (FOXO1s) family and 5-lipoxygenase make an important contribution to atherosclerosis. The aim of this study was to investigate the methylation pattern and polymorphism analysis of FOXO1 and arachidonate 5-lipoxygenase (ALOX5) promoter genes. We studied 50 patients with CAD and 50 age- and sex-matched healthy controls by high resolution melt technique. Overall, we found significant differences between patients and controls in terms of the promoter methylation of ALOX5 (P > 0.05). But there was no significant difference in FOXO1 promoter methylation between patient and controls. Single nucleotide polymorphisms genotyping of rs12762303 and rs2297627, in ALOX5 and FOXO1 genes were demonstrated a significant correlation between mutant allele and the risk of CAD, respectively. Furthermore, there were significant associations between CT + CC genotype and ALOX5 expression. Our findings demonstrated functional effects of single nucleotide polymorphisms (SNPs) and DNA methylation in ALOX5 on mentioned genes expression and they resulted in CAD progression.