表观遗传调控在肥胖症研究领域中的研究进展

肥胖症被认为是一种由遗传因素和环境因素共同决定的复杂型疾病,已成为严重影响现代人类健康的公共卫生问题.在肥胖症的发生和发展过程中,表观遗传调控发挥了极其重要的作用.表观遗传主要的调控方式包括DNA的甲基化修饰,非编码RNA和组蛋白翻译后修饰,近年来组蛋白修饰方向的研究获得了较大突破.在此基础上,本文对表观遗传领域的肥胖症相关研究现状和进展进行了简要综述.     

Epigenetic mechanisms in coronary artery disease: The current state and prospects

Coronary artery disease (CAD) is the leading cause of morbidity and mortality. CAD has both genetic and environmental causes. In the past two decades, the understanding of epigenetics has advanced swiftly and vigorously. It has been demonstrated that epigenetic modifications are associated with the onset and progression of CAD. This review aims to improve the understanding of the epigenetic mechanisms closely related to CAD and to provide a novel perspective on the onset and development of CAD. Epigenetic changes include DNA methylation, histone modification, microRNA and lncRNA, which are interrelated with critical genes and influence the expression of those genes. In addition, miRNA plays a diverse role in the pathological process of CAD. Numerous studies have found that some cardiac-specific miRNAs have potential as certain diagnostic biomarkers and treatment targets for CAD. In this review, the aberrant epigenetic mechanisms that contribute to CAD will be discussed. We will also provide novel insight into the epigenetic mechanisms that target CAD.     

Epigenetic drugs as immunomodulators for combination therapies in solid tumors

Continuously improving knowledge of the fine mechanisms regulating cross-talk between immune cells, and of their multi-faceted interactions with cancer cells, has prompted the development of several novel immunotherapeutic strategies for cancer treatment. Among these, modulation of the host's immune system by targeting immunological synapses has shown notable clinical efficacy in different tumor types. Despite this, objective clinical responses and, more importantly, long-term survival are achieved only by a fraction of patients; therefore, identification of the mechanism(s) responsible for the differential effectiveness of immune checkpoint blockade in specific patient populations is an area of intense investigation. Neoplastic cells can activate multiple mechanisms to escape from immune control; among these, epigenetic reprogramming is emerging as a key player. Selected tumor-associated antigens, Human Leukocyte Antigens, and accessory/co-stimulatory molecules required for efficient recognition of neoplastic cells by the immune system have been shown to be epigenetically silenced or down-regulated in cancer. Consistent with the inherent reversibility of epigenetic silencing, “epigenetic” drugs, such as inhibitors of DNA methyltransferases and of histone deacetylases, can restore the functional expression of these down-regulated molecules, thus improving the recognition of cancer cells by both the innate and adaptive immune responses. This review focuses on the immunomodulatory activity of epigenetic drugs and on their proposed clinical use in novel combined chemo-immunotherapeutic regimens for the treatment of solid tumors.     

Epigenetics in hepatocellular carcinoma: An update and future therapy perspectives

Hepatocellular carcinoma(HCC),the predominant form of adult liver malignancies,is a global health concern.Its dismal prognosis has prompted recent significant advances in the understanding of its etiology and pathogenesis.The deregulation of epigenetic mechanisms,which maintain heritable gene expression changes and chromatin organization,is implicated in the development of multiple cancers,including HCC.This review summarizes the current knowledge of epigenetic mechanisms in the pathogenesis of HCC,with an emphasis on HCC mediated by chronic hepatitis B virus infection.This review also discusses the encouraging outcomes and lessons learnt from epigenetic therapies for hematological and other solid cancers,and highlights the future potential of similar therapies in the treatment of HCC.     

Dose-dependent effects of R-sulforaphane isothiocyanate on the biology of human mesenchymal stem cells, at dietary amounts, it promotes cell proliferation and reduces senescence and apoptosis, while at anti-cancer drug doses, it has a cytotoxic effect

Brassica vegetables are attracting a great deal of attention as healthy foods because of the fact that they contain substantial amounts of secondary metabolite glucosinolates that are converted into isothiocyanates, such as sulforaphane [(−)1-isothiocyanato-4R-(methylsulfinyl)-butane] (R-SFN), through the actions of chopping or chewing the vegetables. Several studies have analyzed the biological and molecular mechanisms of the anti-cancer activity of synthetic R,S-sulforaphane, which is thought to be a result of its antioxidant properties and its ability to inhibit histone deacetylase enzymes (HDAC). Few studies have addressed the possible antioxidant effects of R-SFN, which could protect cells from the free radical damage that strongly contribute to aging. Moreover, little is known about the effect of R-SFN on stem cells whose longevity is implicated in human aging. We evaluated the effects of R-SFN on the biology on human mesenchymal stem cells (MSCs), which, in addition to their ability to differentiate into mesenchymal tissues, support hematopoiesis, and contribute to the homeostatic maintenance of many organs and tissues. Our investigation found evidence that low doses of R-SFN promote MSCs proliferation and protect them from apoptosis and senescence, while higher doses have a cytotoxic effect, leading to the induction of cell cycle arrest, programmed cell death and senescence. The beneficial effects of R-SFN may be ascribed to its antioxidant properties, which were observed when MSC cultures were incubated with low doses of R-SFN. Its cytotoxic effects, which were observed after treating MSCs with high doses of R-SFN, could be attributed to its HDAC inhibitory activity. In summary, we found that R-SFN, like many other dietary supplements, exhibits a hormetic behavior; it is able to induce biologically opposite effects at different doses.     

Epigenetic changes related to glucose metabolism in type 1 diabetes after BCG vaccinations: A vital role for KDM2B

BackgroundA recent epigenome-wide association study of genes associated with type 2 diabetics (T2D), used integrative cross-omics analysis to identify 22 abnormally methylated CpG sites associated with insulin and glucose metabolism. Here, in this epigenetic analysis we preliminarily determine whether the same CpG sites identified in T2D also apply to type 1 diabetes (T1D). We then determine whether BCG vaccination could correct the abnormal methylation patterns, considering that the two diseases share metabolic derangements.MethodsT1D (n = 13) and control (n = 8) subjects were studied at baseline and then T1D subjects studied yearly for 3 years after receiving BCG vaccinations in a clinical trial. In this biomarker analysis, methylation patterns were evaluated on CD4+ T-lymphocytes from baseline and yearly blood samples using the human Illumina Methylation EPIC Bead Chip. Methylation analysis combined with mRNA analysis using RNAseq.ResultsBroad but not complete overlap was observed between T1D and T2D in CpG sites with abnormal methylation. And in the three-year observation period after BCG vaccinations, the majority of the abnormal methylation sites were corrected in vivo. Genes of particular interest were related to oxidative phosphorylation (CPT1A, LETM1, ABCG1), to the histone lysine demethylase gene (KDM2B), and mTOR signaling through the DDIT4 gene. The highlighted CpG sites for both KDM2B and DDIT4 genes were hypomethylated at baseline compared to controls; BCG vaccination corrected the defect by hypermethylation.ConclusionsGlycolysis is regulated by methylation of genes. This study unexpectedly identified both KDM2B and DDIT4 as genes controlling BCG-driven re-methylation of histones, and the activation of the mTOR pathway for facilitated glucose transport respectively. The BCG effect at the gene level was confirmed by reciprocal mRNA changes. The DDIT4 gene with known inhibitory role of mTOR was re-methylated after BCG, a step likely to allow improved glucose transport. BCGs driven methylation of KDM2B’s site should halt augmented histone activity, a step known to allow cytokine activation and increased glycolysis.     

组蛋白去乙酰化酶调控血管发生:一种可能的改善卒中的治疗策略

目前,急性缺血性卒中最有效的治疗方法是在发病3～6 h内应用组织型纤溶酶原激活剂进行动脉或静脉溶栓治疗,但治疗时间窗狭窄和颅内出血风险限制了其临床应用.血管新生是指从业已存在的血管网络以发芽的方式形成新的功能性血管的过程.越来越多的研究表明,组蛋白去乙酰化酶参与了血管发生的调控.通过干预组蛋白去乙酰化酶调控血管发生有可能成为一种改善卒中的治疗策略.