糖尿病模型大鼠视网膜PGC-1α表达和表观遗传修饰的变化

目的 通过检测糖尿病模型大鼠视网膜过氧化物酶体增生物激活受体γ辅助激活因子1α（PGC-1α）mRNA和蛋白表达以及PPARGC1A启动子区DNA甲基化的改变,探讨糖尿病发生和发展过程中PGC-1α的变化趋势、表观遗传学修饰改变及其在糖尿病视网膜病变（DR）代谢记忆中的作用.方法 取清洁级6～7周龄雄性SD大鼠80只,其中60只采用腹腔内注射链脲佐菌素（STZ）的方法建立糖尿病大鼠模型.将60只糖尿病模型大鼠应用随机数字表法随机分为3个组：血糖控制不佳组大鼠造模后4个月内血糖水平控制不佳;血糖半控制组大鼠造模后2个月内血糖水平控制不佳,2个月后维持正常血糖水平;血糖控制组大鼠造模后4个月内均保持正常血糖水平,每组各20只.对照组为周龄匹配的正常饲养大鼠20只.分离各实验组大鼠视网膜组织,应用实时荧光定量PCR法检测PGC-1α及超氧化物歧化酶2（SOD2） mRNA的表达,应用Western blot法检测PGC-1α及锰超氧化物歧化酶（MnSOD）蛋白的表达,应用亚硫酸氢钠测序法（BSP）检测PPARGC1A启动子区DNA甲基化状态的变化.结果 造模后4个月,对照组大鼠体质量明显高于血糖控制不佳组、血糖半控制组和血糖控制组,血糖控制不佳组血糖水平显著高于对照组,差异均有统计学意义（均P=0.000）.血糖控制组、血糖半控制组和血糖控制不佳组大鼠视网膜组织中PGC-1 αmRNA相对表达量依次下降,均低于对照组,差异均有统计学意义（均P=0.000）;血糖控制组PGC-1αmRNA相对表达量明显高于血糖控制不佳组,差异有统计学意义（P=0.002）.血糖控制组、血糖半控制组和血糖控制不佳组大鼠视网膜组织中SOD2 mRNA表达依次增加,均高于对照组,差异均有统计学意义（P=0.006、0.000、0.000）;血糖控制组与血糖控制不佳组SOD2 mRNA相对表达量比较,差异有统计学意义（P=0.001）.血糖控制不佳组、血糖半控制组和血糖控制组大鼠视网膜中PGC-1α蛋白和MnSOD蛋白相对表达量显著低于对照组,血糖控制组大鼠视网膜PGC-1α蛋白相对表达量显著高于血糖控制不佳组,差异均有统计学意义（均P＜0.05）.糖尿病模型大鼠视网膜组织中PPARGC1A启动子区DNA甲基化水平升高,血糖控制不佳组、血糖半控制组大鼠视网膜组织中PPARGC1A启动子区DNA甲基化的水平较对照组明显升高,差异均有统计学意义（P=0.008、0.031）,血糖半控制组与血糖控制不佳组间比较,差异无统计学意义（P＞0.05）.结论 糖尿病模型大鼠视网膜PGC-1αmRNA及蛋白表达均下降,视网膜SOD2 mRNA表达升高,MnSOD蛋白表达下降,具有代谢记忆的特点.PPARGC1A启动子区DNA甲基化水平的升高可能与PGC-1α表达受到抑制以及代谢记忆相关.

Re-searching nasopharyngeal carcinoma

Nasopharyngeal carcinoma(NPC)has been a focus of medical research for more than 100 years,with significant interest emerging over the last 58 years following the identification of the link between the disease and Epstein-Barr virus(EBV)infection.NPC possesses several distinctive characteristics among human cancers,notably its well-documented global epidemiology,which reveals localized high-incidence regions primarily in Southeast Asia,particularly in the Southern provinces of China near the Pearl river,as well as in Greenland and North Africa.Epidemiological data indicate a marked male predominance,early disease onset,and a nearly 100%prevalence of latent EBV infection in the tumors.Due to lack of consistent pattern of cancer-related mutations in NPC genomes and excessive DNA-methylation in the tumor cells,NPC can be considered"an epigenetic cancer".Despite extensive researches,convincing biological explanations for these unique characteristics remain elusive.Recently,suggestive evidence has been published that specific local variants of EBV may represent major high risk factors.In spite of tumor and virus specific immunity,it has not been possible to use this for improved treatment.Ongoing studies on the role of the local microflora and tumor microenvironment are essential for a comprehensive understanding of host-EBV-tumor interactions.Ultimately,this knowledge aims to enhance diagnosis,disease fractionation,treatment strategies,and potentially prevention of NPC.

Plant Genomic Imprinting and Its Effect on Seed Development

Genomic imprinting is the epigenetic phenomenon by which certain genes are expressed in a parent-of-origin-specific manner, and was first discovered in mammalian embryos. Recent studies have shown that it also occurs in developing plant seeds, and is now becoming a hot topic of biology of plant seed development. According to the previous studies on imprinted genes, imprinting mechanism and their roles in plant seed development, the current progress of genomic imprinting in plant seed development was summarized and possible strategies were proposed to deal with the problems, which could provide helpful information for further research.

Epigenetic Effects of Special Plant Nutritional Elements(SPNE) on Four Generations of Conventional Rice

[Objective] The epigenetic effects of special plant nutritional elements （SP-NE） on 4 generations of conventional rice were investigated. [Method] The 4 gener-ations of a conventional rice cultivar were al treated with the SPNE. The effects of SPNE on the yield of the 4 generations were investigated. From the 1st generation to the 4th generations, some seeds were treated with the SPNE and water alterna-tively, and some seeds were treated with the SPNE persistently. Under these condi-tions, the effects of SPNE on the yield of rice were studied. In addition, the epige-netic effects of spraying times of SPNE on the yield of rice within the same gener-ation were studied. According to the national standard for pol utant content in food （GB 2762-2012）, the heavy metal content, particularly the Cd content, and the pro-tein content in rice grains were determined. [Result] The increase and the epigenetic increase of yield of rice treated with SPNE were al enlarged generation by genera-tion. The yield differed among different plots even under the same SPNE treatment. But the yield increase was similar within the same plot. The epigenetic effects of spraying times of SPNE on the yield were also similar. The pol utant content in rice grains was al less than the limited content required by the national standard. The Cd content was lower and the protein content was higher in the rice treated with SPNE compared to that in the rice treated with water, indicating the rice treated with SPNE was more safe and nutritional. [Conclusion] We hope to provide a theo-retical basis for the production of conventional rice.

Genomic and genetic alterations influence the progression of gastric cancer

Gastric cancer is one of the leading causes of cancerrelated deaths worldwide, although the incidence has gradually decreased in many Western countries. Two main gastric cancer histotypes, intestinal and diffuse, are recognised. Although most of the described genetic alterations have been observed in both types, different genetic pathways have been hypothesized. Genetic and epigenetic events, including 1q loss of heterozygosity (LOH), microsatellite instability and hypermethylation, have mostly been reported in intestinal-type gastric carcinoma and its precursor lesions, whereas 17p LOH, mutation or loss of E-cadherin are more often implicated in the development of diffuse-type gastric cancer.In this review, we summarize the sometimes contradictory findings regarding those markers which influence the progression of gastric adenocarcinoma.

Genetic and epigenetic variants influencing the development of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease （NAFLD） is common worldwide. The importance of genetic and epigen- eric changes in etiology and pathogenesis of NAFLD has been increasingly recognized. However, the ex- act mechanism is largely unknown. A large number of single nucleotide polymorphisms （SNPs） related to NAFLD has been documented by candidate gene studies （CGSs）. Among these genes, peroxisome pro- liferatoractivated receptor-γ, adiponectin, leptin and tumor necrosis factor-α were frequently reported. Since the introduction of genome-wide association studies （GWASs）, there have been significant advances in our understanding of genomic variations of NAFLD. Patatin- like phospholipase domain containing family member A3 （PNPLA3, SNP rs738409, encoding I148M）, also termed adiponutrin, has caught most attention. The evidence that PNPLA3 is associated with increased hepatic fat levels and hepatic inflammation has been validated by a series of studies. Epigenetic modification refers to phenotypic changes caused by an adaptive mechanism unrelated to alteration of primary DNA se- quences. Epigenetic regulation mainly includes microR- NAs （miRs）, DNA methylation, histone modifications and ubiquitination, among which miRs are studied most extensively, miRs are small natural single stranded RNA molecules regulating mRNA degradation or translation inhibition, subsequently altering protein expression of target genes. The miR-122, a highly abundant miR ac- counting for nearly 70% of all miRs in the liver, is sig- nificantly under-expressed in NAFLD subjects. Inhibition of miR-122 with an antisense oligonucleotide results in decreased mRNA expression of lipogenJc genes and improvement of liver steatosis. The investigation into epigenetic involvement in NAFLD pathogenesis is just at the beginning and needs to be refined. This review summarizes the roles of genetics and epigenetics in the development of NAFLD. The progress made in this field may provide novel diagnostic biomarkers and therapeu- tic targets for NAFLD management.

Epigenetics： heterochromatin meets RNAi

The term epigenetics refers to heritable changes not encoded by DNA. The organization of DNA into chromatin fibers affects gene expression in a heritable manner and is therefore one mechanism of epigenetic inheritance. Large parts of eukaryotic genomes consist of constitutively highly condensed heterochromatin, important for maintaining genome integrity but also for silencing of genes within. Small RNA, together with factors typically associated with RNA interference （RNAi） targets homologous DNA sequences and recruits factors that modify the chromatin, com- monly resulting in formation of heterochromatin and silencing of target genes. The scope of this review is to provide an overview of the roles of small RNA and the RNAi components, Dicer, Argonaute and RNA dependent polymerases in epigenetic inheritance via heterochromatin formation, exemplified with pathways from unicellular eukaryotes, plants and animals.

Targeting histone deacetylases： perspectives for epigenetic-based therapy in cardio-cerebrovascular disease

Although the pathogenesis of cardio-cerebrovascular disease （CCVD） is multifactorial, an increasing number of experimental and clinical studies have highlighted the importance of histone deacetylase （HDAC）-mediated epigenetic processes in the development of cardio-cerebrovascular injury. HDACs are a family of enzymes to balance the acetylation activities of histone acetyltransferases on chromatin remodeling and play essential roles in regulating gene transcription. To date, 18 mammalian HDACs are identified and grouped into four classes based on similarity to yeast orthologs. The zinc-dependent HDAC family currently consists of 11 members divided into three classes （class I, II, and IV） on the basis of structure, sequence homology, and domain organization. In comparison, class III HDACs （also known as the sirtuins） are composed of a family of NAD＋-dependent protein-modifying enzymes related to the Sir2 gene. HDAC inhibitors are a group of compounds that block HDAC activities typically by binding to the zinc-containing catalytic domain of HDACs and have displayed an- ti-inflammatory and antifibrotic effects in the cardio-cerebrovascular system. In this review, we summarize the current knowledge about classifications, functions of HDACs and their roles and regulatory mechanisms in the cardio-cerebrovascular system. Pharmacological tar- geting of HDAC-mediated epigenetic processes may open new therapeutic avenues for the treatment of CCVD.

The Protamine-like DNA-binding Protein P6.9 Epigenetically Up-regulates Autographa californica Multiple Nucleopolyhedrovirus Gene Transcription in the Late Infection Phase

Protamines are a group of highly basic proteins first discovered in spermatozoon that allow for denser packaging of DNA than histones and will result in down-regulation of gene transcription^l~. It is well recognized that the Autographa californica multicapsid nucleopolyhedrovirus （AcMNPV） encodes P6.9, a protamine-like protein that forms the viral subnucleosome through binding to the viral genome[29]. Previous research demonstrates that P6.9 is essential for viral nucleocapsid assembly, while it has no influence on viral genome replication1311. In the present study, the role of P6.9 in viral gene transcription regulation is characterized. In contrast to protamines or other protamine-like proteins that usually down-regulate gene transcription, P6.9 appears to up-regulate viral gene transcription at 12-24 hours post infection （hpi）, whereas it is non-essential for the basal level of viral gene transcription. Fluorescence microscopy reveals the P6.9＇s co-localization with DNA is temporally and spatially synchronized with P6.9＇s impact on viral gene transcription, indicating the P6.9-DNA association contributes to transcription regulation. Chromatin fractionation assay further reveals an unexpected co-existence of P6.9 and host RNA polymerase II in the same transcriptionally active chromatin fraction at 24 hpi, which may probably contribute to viral gene transcription up-regulation in the late infection phase.

Genomic Imprinting—The Story of the Other Half and the Conflicts of Silencing

G-enomic imprinting is an epigenetic mechanism that produces functional differences between the paternal and mammal genomes and plays an essential role in mammalian development and growth. There are a number of genes in our genomes that are subject to genomic imprinting where one parent＇s copy of the gene is expressed while the other is silent. Silencing of one allele predetermines that any function ascribed to that gene are now dependant on the single active copy. Possession of only a single active allele can lead to deleterious health consequences in humans. If imprinted genes are crucial in mammalian development, one would also expect mutations in these genes to cause diseases. Since imprinting is an epigenetic mechanism, mistakes in maintaining epigenetic mark also cause imprinting disorders. Here we in this review focus on the current understanding of this unique genetic mechanism more than two decades after the first description of the imprinting phenomenon was given by McGrath and Solter. Although the possible molecular mechanisms by which imprinting is imposed and maintained are being identified, we have a long way to go in understanding the molecular mechanisms that regulate the expression of these oddly behaving genes, the function of imprinting and the evolution. Post genomic technologies might ultimately lead to a better understanding of the ＇imprinting effects＇.

From Bench to Bedside： Targeting Epigenetics for Cancer Therapy

The initiation and progression of cancer not only involves genetic abnormalities, but also epigenetic alterations, such as DNA methylation and histone modifications. Epigenetics refers to the heritable changes that do not involve any structural changes in the target gene, i.e., DNA sequence and protein sequence. Thus, these epigenetic aberrations are potentially reversible, allowing the malignant cells to revert to a state with more normal characteristics. The use of epigenetics is emerging as an effective and promising approach to treat cancer. Epigenetic drugs, which target two well- known epigenetic pathways, namely, DNA methyltransferases and histone deacetylases, are already being applied for the cancer treatment. In the current study, an overview regarding the under-standing of epigenetic alterations in the development of cancer and the current state of epigenetic drug discovery is provided.

Epigenetic regulation mechanism of ABCG2 induced drug-resistant phenotype

The aim of this study is to investigate epigenetic mechanism of ABCG2 induced drug-resistance. It is not only expatiate for drug-resistance regulation mechanism in all-round, but also to provide scientific experimental basis for selecting target to reverse its drug-resistance. Apply methylation-specific PCR （MSP） to have tested methylation of ABCG2 promoter region -359 to -353 specific positions in breast cancer tissues and paired adjacent tissue of 22 cases and test their methylation positions with MSP products for sequencing; and adopt fluorescent quantitation RT-PCR to test expression level DNMT1, DNMT3A, DNMT3B and ABCG2; to make analysis on relationship between them with statistical spearman correlation. Specific positions of ABCG2 gene promoter region of 18 cases among the 22 cases with breast cancer （18/22, 82%） existed high methylation （P〈0.05）, MSP products sequencing proved methylation of the specific position, and mRNA expression level was relative higher in remarkable positive correlation （P〈0.05） ABCG2, DNMT1, DNMT3A, DNMT3B mRNA expression levels in breast cancer tissues were obviously higher than adjacent tissues （P〈0.01）, and DNMT3B expression level was obviously higher than DNMT1 and DNMT3A （P〈0.01） in negative correlation with ABCG2 gene expression （P=0.001）. -359 to -353 positions of promoter regions of ABCG2gene existed high methylation capable to push expression of this gene in beast cancer tissue. DNMT3B is involved in expression regulation in ABCG2 gene, and provides new scientific basis for drug-resistance target as reverse ABCG2 induction

Effects of Traditional Chinese Medicine in Prevention and Treatment of Breast Cancer with a focus on epigenetics regulation

Breast cancer has been an important factor that influenced women＇s health with its increasing incidence. The conventional research suggests that breast cancer is caused by genetic mutations, while some advanced studies have found that epigenetics plays an important role in the pathogenesis, prognosis, prevention and treatment of breast cancer Epigenetics is a new direction of research in the field of life sciences. Traditional Chinese medicine, like surgery, radiotherapy, chemotherapy and endocrinotherapy, is an important part of comprehensive treatment of breast cancer.

Expectation： Advances and Entropy Analysis of Plant Epigenetics under Stress

Life depends on negative entropy, and the growth of plants depends on the negative entropy flow of sunlight and the ecological environment. Plants are fixed on the ground, cannot actively escape from the external hazards, and thus relies on some of their own response mechanism to defend against various external stress. Due to the limited responsiveness of the plants, the negative entropy operation of the open system is hindered, which results in the death of plants in a large number.Epigenetic regulation plays an important role in this response mechanism, mainly in DNA methylation, histone modification, chromatin remodeling, and noncoding RNA. In this paper, the regulation mechanism of epigenetic modification under various stresses and the analysis of entropy were reviewed, providing a basis for the study of crop resistance.

Effects of Traditional Chinese medicine in Prevention and Treatment of Breast Cancer with a focus on epigenetics regulation

Breast cancer has been an important factor that influenced women＇s health with its increasing incidence. The conventional research suggests that breast cancer is caused by genetic mutations, while some advanced studies have found that epigenetics plays an important role in the pathogenesis, prognosis, prevention and treatment of breast cancer Epigenetics is a new direction of research in the field of life sciences. Traditional Chinese medicine, like surgery, radiotherapy, chemotherapy and endocrinotherapy, is an important part of comprehensive treatment of breast cancer, especially in the consolidation phase of treatment period,which can prevent recurrence or metastasis of breast cancer The theory of epigenetics has some similarities with the theory of TCM, such as ~Correspondence between human being and nature＂, ~Tongbing Yizhi＂ （treating the same disease with different methods）, ~Yibing Tongzhi＂ （treating different diseases with the same method） and the constitution science of TCM. Traditional Chinese medicine can be used to regulate epigenetic modification through DNA methylation, histone modification, miRNA, etc.. The abnormality of epigenetic information can be reversed, which is related to transferring balance between Yin and Yang in the body and making the body restore optimal nature state. This article discusses the application of epigenetics in the study of TCM and in the prevention and treatment of breast cancer. It is a multidisciplinary review to explore the basis about epigenetics in prevention and treatment of breast cancer with TCM, and provide a reference for clinical practice

Epigenetic regulation in alcoholic liver disease

Alcoholic liver disease （ALD） is characterized by steatosis or fat deposition in the liver and inflammation, which leads to cirrhosis and hepatocellular carcinoma. Induction of target genes without involving changes in DNA sequence seems to contribute greatly to liver injury. Chromatin modifications including alterations in histones and DNA, as well as post-transcriptional changes collectively referred to as epigenetic effects are altered by alcohol. Recent studies have pointed to a significant role for epigenetic mechanisms at the nucleosomal level influencing gene expression and disease outcome in ALD. Specifically, epigenetic alterations by alcohol include histone modifications such as changes in acetylation and phosphorylation, hypomethylation of DNA, and alterations in miRNAs. These modifications can be induced by alcoholnduced oxidative stress that results in altered recruitment of transcriptional machinery and abnormal gene expression. Delineating these mechanisms in initiation and progression of ALD is becoming a major area of interest. This review summarizes key epigenetic mechanisms that are dysregulated by alcohol in the liver. Alterations by alcohol in histone and DNA modifications, enzymes related to histone acetylation such as histone acetyltransferases, his-tone deacetylases and sirtuins, and methylation enzymes such as DNA methyltransferases are discussed. Chromatin modifications and miRNA alterations that result in immune cell dysfunction contributing to inflammatory cytokine production in ALD is reviewed. Finally, the role of alcohol-mediated oxidative stress in epigenetic regulation in ALD is described. A better understanding of these mechanisms is crucial for designing novel epigenetic based therapies to ameliorate ALD.

Ship Appearance Optimal Design on RCS Reduction Using Response Surface Method and Genetic Algorithms

Radar cross section (RCS) reduction technologies are very important in survivability of the military naval vessels. Ship appearance shaping as an effective countermeasure of RCS reduction redirects the scattered energy from one angular region of interest in space to another region of little interest. To decrease the scattering electromagnetic signals from ship scientifically, optimization methods should be introduced in shaping design. Based on the assumption of the characteristic section design method, mathematical formulations for optimal shaping design were established. Because of the computation-intensive analysis and singularity in shaping optimization, the response surface method (RSM) combined genetic algorithm (GA) was proposed. The poly-nomial response surface method was adopted in model approximation. Then genetic algorithms were employed to solve the surrogate optimization problem. By comparison RCS of the conventional and the optimal design, the superiority and effectiveness of proposed design methodology were verified.

早年创伤对认知功能影响的研究进展

早年创伤是一个全球普遍存在的问题，严重影响儿童、青少年的大脑发育，继而导致认知功能、人格水平、社会行为的改变。早年创伤主要是父母、监护人或其他年长者对孩子施加躯体虐待、躯体忽视、情感虐待、情感忽视或性虐待。美国一项调查显示：儿童虐待事件的发生率高达1．2％[1]。早年创伤影响认知功能的多个领域，包括学习／工作记忆、视觉空间能力、执行功能、言语智能、复杂推理搜决策、学业表现等比]。创伤造成的认知功能改变是目前国内外神经科学和精神医学领域研究的热点，但其发病机制仍不明确，鉴于早年创伤与认知功能的关系问题，现就早年创伤对大脑发育、神经认知的影响加以综述。

DNA methyltransferase inhibitor dramatically alters the secondary metabolism of Pestalotiopsis microspora

5-Azacytidine, a DNA methyltransferase inhibitor, led to significant changes in the secondary metabolism of the plant endophytic fungus, Pestalotiopsis microspora. Analysis of the culture broth extract led to the isolation of a new compound, 4＇-forrnamidophenyl-5-methoxybenzoate （1）, along with seven known polyketides, 4-hydroxybenzoic acid （2）, LL-P880ct （3）, 1＇-hydroxy-4-methoxy-6-pentyl-2H-pyran-2-one （4）, pestalotiollide B （5）, pestalotiopyrone G （6）, endocrocin （7） and 2＇-hydroxy- 6＇-hydroxymethyl-4＇-methylphenyl-2,6-dihydroxy-3-（2-isopentenyl）benzoate （8）. HPLC profiles revealed that all compounds except for 4 belonged to the newly induced secondary metabolites. In addition, all compounds were proved to be devoid of significant antifungal activity in the bioassays.

Reversal of multidrug resistance in cancer treatment by regulating multidrug resistance gene1: focus on nuclear receptors and epigenetics

Overexpression of P-glycoprotein （P-gp） encoded by the multidrug resistance gene-1 （MDR-1） is the main mechanism responsible for multidrug resistance （MDR） in a majority of cancer cells. However, the mechanism by which cancer cells acquire high levels of P-gp has not been well defined. Accumulating evidence suggests that nuclear receptors （NRs）, especially human pregnane X receptor （PXR）, play a crucial role in multidrug resistance. It has been shown that chemotherapeutic drug activates PXR and then enhances P-gp expression. Genetic knockdown or pharmacologic inhibition of PXR led to attenuation of drug-induced MDR1 over expression, implying that NRs may be an effective target to reverse multidrug resistance. Recent investigations suggested that transcriptional activity of NRs is mediated by methylases, the important enzymes involved in epigenetic regulation. Other epigenetic modifications, such as promoter methylation, histone deacetylases and microRNAs, were also found to be involved in activation of MDR1 promoter, though the underlying mechanisms are not thoroughly known. In this review, we summarized recent researches in the regulation of P-gp expression, with particular focus on NRs and epigenetics, aiming to provide references and options to reverse and/or prevent MDR in cancer treatment.