SIRT1基因多态性与广西永福地区人群长寿的关联性

目的 探讨SIRT1基因多态性与广西永福地区人群长寿的关联性.方法 采用长寿对照设计,选取广西壮族自治区永福县共500人为研究对象,包括长寿组223人、平均年龄(93.17±3.08)岁,对照组277人、平均年龄(46.92±17.12)岁.应用聚合酶链反应-高分辨熔解曲线技术结合测序验证法检测SIRT1基因上的rs3758391,rs3740051,rs2273773,rs4746720和rs10997870位点的单核苷酸多态性(single nucleotide polymorphisms,SNP)的分布情况,比较长寿组与对照组人群的等位基因、基因型频率的分布特征,分析SIRT1基因多态性与长寿的关联性.结果 长寿组rs4746720位点CT基因型频率高于CC和TT基因型频率,差异具有统计学意义(P=0.000,OR=2.098,95％CI:1.412-4.117),其等位基因频率在两组间分布的差异无统计学意义.rs3758391 、rs3740051 、rs2273773位点的基因型频率和等位基因频率在长寿组和对照组间分布的差异均无统计学意义.结论 SIRT1基因rs4746720单核苷酸多态性与广西永福地区长寿人群相关联.     

SIRT6在大鼠脑组织中的表达与分布

目的研究SITR6蛋白在正常大鼠脑组织中的表达与分布。方法在常温下自由饮水与饮食的情况下喂养8周的大鼠,采用免疫组织化学检测大鼠脑组织中SIRT6的表达与定位。结果 SIRT6是一种主要在神经元中表达的核蛋白,在大鼠正常脑组织中广泛表达,尤其在大脑组织中的皮质、髓质、海马中的神经元表达量较高;且在海马集中表达和在大脑皮质的外锥体细胞层和内椎体细胞层较明显,而在大脑髓质中表达低于海马和皮质。结论 SIRT6作为一种核蛋白,为研究SIRT6的功能提供了新的思路。     

孤独症AUTS2基因罕见变异筛选及其对鼠神经元树突发育的影响

目的:探讨中国汉族孤独症患者是否携带孤独症易感候选基因2(AUTS2)有害罕见变异,及其对鼠神经元树突发育的影响。方法:对96例符合DSM-IV孤独症诊断标准的中国汉族孤独症患者AUTS2基因进行靶向测序筛选罕见变异,进一步扩大样本在766例孤独症患者和864例正常对照中采用Sanger测序法进行验证,继而构建有害罕见变异质粒,转染至敲低内源性Auts2的原代培养SD乳鼠皮层神经元,观察神经元树突总长度和分支数量。结果:AUTS2基因2个罕见错义突变c.44G>T(Arg15Leu)和c.1774C>G(Pro592Ala)仅孤独症患者携带,功能预测为有害突变。此2个罕见错义突变导致SD乳鼠皮层神经元顶树突和基树突的总长度和分支数量均显著减少(P<0.05)。结论:中国汉族人群孤独症AUTS2基因存在2个有害罕见错义突变,能影响大鼠神经元树突发育,可能参与孤独症的发病。     

双侧罕见的椎动脉变异1例

在解剖一具成年男性尸体时发现:左椎动脉在左颈总动脉与左锁骨下动脉之间于主动脉弓的上方发出,起始部外径3.5mm,经颈交感神经节前方,在左颈总动脉的后外侧、左颈内静脉的后内侧之间上行,达甲状软骨上缘水平进入第4颈椎横突孔,该动脉全长为9.6cm,入横突孔处的外径为2.2mm。     

广西柳州地区β珠蛋白基因的变异分析

目的分析广西柳州地区β-珠蛋白生成障碍性贫血(β-地中海贫血)基因型构成及分布情况,为本地区地中海贫血防治工作提供参考。方法对2017年1月至12月到柳州市妇幼保健院进行婚检、产检或体检的13847例受检者,采用反向点杂交技术(reverse dot blot,RDB)检测中国人群常见的17种β-珠蛋白基因点变异,对于筛查结果与人群常见变异类型结果不吻合的病例运用Sanger测序法对其β-珠蛋白基因进行检测。结果13847例受检样本中,检出β-地中海贫血基因变异2098例(15.15%),其中杂合变异2075例(98.90%),复合杂合变异12例(0.57%),纯合变异11例(0.52%),以CD41-42(48.43%)、CD17(31.45%)、IVS-Ⅱ-654(6.33%)型最为常见。β-地中海贫血复合α-地中海贫血共338例,以复合--SEA/αα、-α3.7/αα、αCSα/αα、-α4.2/αα为主。发现β-32/βN,βCD41-42/βIVS-II-5,βCD30/βN等罕见病例。结论广西柳州地区是β-地中海贫血的高发区,其变异谱复杂多样,临床表型也各不相同,与其它地区存在差异。本研究为柳州地区地贫人群进行遗传咨询、产前诊断及制定有针对性的β-地中海贫血防治计划提供数据基础。     

精神分裂症中拷贝数变异的研究新进展

精神分裂症(schizophrenia,MIM 181500)是最严重精神疾病之一,在世界范围发病率为1%左右.为双生子、家系、寄养子的研究结果,提供了强有力的证据,表明精神分裂症是一种复杂的遗传疾病,遗传因素对精神分裂症的影响大约占了73%～90%.随着现代芯片技术的发展,基于"常见疾病常见变异"模型的全基因组研究为我们认识精神分裂症的遗传机制提供了新的视野,与此同时拷贝数变异作为一种新型的遗传标记在精神分裂症的遗传学研究中崭露头角.与精神分裂症显著关联的1q21.1、15q11.2、15q13.3、16p11.2、16p13.1、22q11、NRXN1等位点的罕见拷贝数变异在不同的研究中得到了反复验证;罕见拷贝数变异的增加极大增加了患病风险;精神分裂症遗传学研究中的"常见疾病罕见变异"的理论正在形成.     

SIRT6和HIF-1α在三阴性乳腺癌中的表达及临床价值

目的 探索SIRT6基因与缺氧诱导因子（HIF-1α）在三阴性乳腺癌（TNBC）中的表达关系,分析二者相关性及临床价值。方法 收集2017年6月~2018年12月佳木斯大学附属第一医院病理科60例TNBC乳腺癌组织及其对应60例腋窝淋巴结病理组织,并取癌旁正常组织40例。采用免疫组化法检测癌组织、转移淋巴结及癌旁组织中SIRT6、HIF-1α表达,分析二者表达与TNBC乳腺癌临床病理参数、发生发展的关系以及二者表达的相关性。结果 SIRT6在TNBC乳腺癌组织中表达阳性率（80.00%）高于癌旁组织（24.00%）,差异有统计学意义（P＜0.05）,其表达与TNBC乳腺癌组织分化程度,临床TNM分期、转移淋巴结有关（P＜0.05）;在TNBC乳腺癌组织、癌旁组织中HIF-1α的阳性率分别为86.67%、15.00%。且HIF-1α在TNBC乳腺癌组织与癌旁组织表达差异有统计学意义（P＜0.05）。并与TNBC乳腺癌的组织分化程度,临床TNM分期、转移淋巴结相关（P＜0.05）;在TNBC乳腺癌中SIRT6与HIF-1α的表达呈正相关（r=0.823,P＜0.05）。结论 在TNBC乳腺癌中SIRT6与HIF-1α的较高的阳性表达率可能与其发生发展及早期转移有关,检测SIRT6与HIF-1α将有助于了解TNBC乳腺癌的进展及侵袭转移情况,它们有希望为TNBC乳腺癌的早期发现、治疗及预后的评估提供新的研究思路。     

一例由 KCNJ6基因新发变异导致的Keppen-Lubinsky综合征患儿的临床及遗传学分析

目的:探讨1例由 KCNJ6基因新发变异导致的Keppen-Lubinsky综合征患儿的临床及遗传学特点。 方法:应用全外显子组测序对患儿及其父母进行基因检测,并用生物信息学软件预测其危害性,并通过蛋白质结构模拟分析其影响。结果:患儿具有特殊面容,表现为大眼、鼻翼发育不全、小后缩下颌及早衰模样,同...     

长寿老人血脂,脂蛋白和载脂蛋白价值的研究

对９０岁以上３６例长寿老人的血脂、脂蛋白和载脂蛋白进行了测定，并与陈旧性心肌梗塞（ＯＭＩ）和成人组对比。结果显示：与ＯＭＩ组比较，长寿老人血清ＨＤＬ－ｃ／ＴＣ、ＨＤＬ－ｃ／ＬＤＬ－Ｃ和ＡｐｏＡ１／ＡｐｏＢ１００比率明显高于ＯＭＩ，而ＴＣ、ＴＧ、ＬＤｃ、ＶＬＤＬ－ｃ、ＡｐｏＢ１００和ＡｐｏＡ１明显低于ＯＭＩ，ＨＤＬ－ｃ在两组间无显著性差异，与成人组比较，长寿老人血清ＴＧ、ＶＬＤＬ－ｃ、ＡｐｏＡ、／Ａ     

广西巴马长寿老人的长寿相关线粒体基因组研究

目的 探讨人类线粒体基因与广西巴马长寿的关联性.方法 对广西巴马96岁以上的20个老人外周血液中线粒体全序列进行测定,并与标准剑桥参考序列(Cambridge reference sequence,CRS)比对确定7个候选线粒体基因单核苷酸多态位点.用586名无亲缘关系的健康人群血样作为对照.并进一步用限制性片段长度多态性方法对候选基因进行检验.结果 线粒体DNA(mitochondrial DNA,mtDNA)4824A/G位点突变率在长寿和健康正常对照群体不同年龄段之间,随年龄增加突变频率逐渐提高,且对照人群样本突变率明显高于长寿人群,差异具有统计学意义.结论 mtDNA4824位点不仅是衰老相关位点,也是长寿负相关位点.     

Functional dissection of SIRT6: Identification of domains that regulate histone deacetylase activity and chromatin localization

The mammalian sirtuin SIRT6 is a site-specific histone deacetylase that regulates chromatin structure. SIRT6 is implicated in fundamental biological processes in aging, including maintaining telomere integrity, fine-tuning aging-associated gene expression programs, preventing genomic instability, and maintaining metabolic homeostasis. Despite these important functions, the basic molecular determinants of SIRT6 enzymatic function - including the mechanistic and regulatory roles of specific domains of SIRT6 - are not well understood. Sirtuin proteins consist of a conserved central ‘sirtuin domain’ - thought to comprise an enzymatic core - flanked by variable N- and C-terminal extensions. Here, we report the identification of novel functions for the N- and C-terminal domains of the human SIRT6 protein. We show that the C-terminal extension (CTE) of SIRT6 contributes to proper nuclear localization but is dispensable for enzymatic activity. In contrast, the N-terminal extension (NTE) of SIRT6 is critical for chromatin association and intrinsic catalytic activity. Surprisingly, mutation of a conserved catalytic histidine residue in the core sirtuin domain not only abrogates SIRT6 enzymatic activity but also leads to impaired chromatin association in cells. Together, our observations define important biochemical and cellular roles of specific SIRT6 domains, and provide mechanistic insight into the potential role of these domains as targets for physiologic and pharmacologic modulation.     

SgD-CNV, a database for common and rare copy number variants in three Asian populations

Copy number variants (CNVs) extend our understanding of the genetic diversity in humans. However, the distribution and characteristics of CNVs in Asian populations remain largely unexplored, especially for rare CNVs that have emerged as important genetic factors for complex traits. In the present study, we performed an in-depth investigation of common and rare CNVs across 8,148 individuals from the three major Asian ethnic groups: Chinese (n = 1,945), Malays (n = 2,399), and Indians (n = 2,217) in Singapore, making this investigation the most comprehensive genome-wide survey of CNVs outside the European-ancestry populations to date. We detected about 16 CNVs per individual and the ratio of loss to gain events is ～2:1. The majority of the CNVs are of low frequency (<10%), and 40% are rare (<1%). In each population, ～20% of the CNVs are not previously catalogued in the Database of Genomic Variants (DGV). Contrary to findings from European studies, the common CNVs (>5%) in our populations are not well tagged by SNPs in Illumina 1M and 610K arrays, and most disease-associated common CNVs previously reported in Caucasians are rare in our populations. We also report noticeable population differentiation in the CNV landscape of these Asian populations, with the greatest diversity seen between the Indians and the Chinese.     

Expression and function of SIRT6 in muscle invasive urothelial carcinoma of the bladder

SIRT6, a member of the class III histone deacetylase, has been shown to inhibit glycolysis and promote DNA double strand break repairs. Despite of its proposed tumor suppressor role, no significant differences in SIRT6 mRNA levels among normal bladder urothelium, non-muscle invasive, and muscle invasive urothelial carcinoma were noted in the two largest bladder cancer gene expression datasets available in Oncomine^TM. We therefore studied the expression and function of SIRT6 in muscle invasive urothelial carcinoma of the bladder. Immunohistochemistry studies of SIRT6 on radical cystectomy samples showed a dramatic decline of SIRT6 expression when bladder cancer progressed from T2 to T4. Functional study with bladder cancer cell lines confirmed its role in inhibiting glycolysis and cell proliferation. Reducing SIRT6 with siRNA, however, did not sensitize bladder cancer cells to drug induced DNA damage. The differential expression patterns of SIRT6 amongst different T stages of muscle invasive bladder cancers indicate less reliance on glycolysis when urothelial carcinoma invades deeper through the bladder and into the adjacent tissues.     

Ⅲ型固有淋巴细胞中SIRT6在小鼠结肠炎中作用的初探

肠道组织高表达表观遗传调控因子沉默信息调节因子(silent information regulator 6, SIRT6),在UC患者及动物模型的结肠组织中,SIRT6的表达水平显著下调。关于SIRT6在调控肠道免疫平衡中的作用尚不清楚。新近发现的Ⅲ型固有淋巴细胞(group 3 innate lymphoid cell, ILC3)主要分布于肠道,对维持肠道免疫稳态非常重要。为探讨ILC3中SIRT6在结肠炎发生发展中的作用,应用FCM检测小鼠肠道组织中固有淋巴细胞(innate lymphoid cell, ILC)亚群比例,FACS分选ILC,荧光定量PCR检测Sirt6表达。结果发现,Sirt6在ILC3中有较高的表达丰度。运用Cre-loxp系统建立ILC3条件性敲除Sirt6小鼠模型,观察基础状态以及葡聚糖硫酸钠(dextran sulfate sodium salt, DSS)诱导性肠炎模型中小鼠的表型变化。结果显示,Sirt6在ILC3中缺失并不影响基础状态下小鼠的生长发育和肠道结构,但能显著提高小鼠对DSS诱导性结肠炎的抵抗能力。以上结果提示SIRT6通过调控ILC3影响肠炎的发生发展过程。     

Polymorphisms and rare variants identified by next-generation sequencing confer risk for lung cancer in han Chinese population

BackgroundLung cancer is one of the leading causes of cancer death worldwide, and genetic risk factors account for a large part of its carcinogenesis. The low economic requirements and high efficiency of next-generation sequencing (NGS) make it widely used in detecting genetic alterations in pathogenesis.MethodsWe performed targeted panel sequencing in 780 Han Chinese lung cancer patients using a commercial probe, and the correlations between dozens of susceptible sites were verified in 1113 healthy controls. This study used Fisher's exact test and Benjamini-Hochberg FDR correction to analyze the mutual exclusion between mutated genes, and Pearson's p was used to verify the correlations between mutations and lung cancer susceptibility.ResultsOur results determined the mutation spectrum and showed that each lung cancer patient carried at least one DNA mutation. The most frequently mutated gene was BRCA2 (mutation rate,10.6 %.). The co-occurrence and mutual exclusion analysis of DNA damage related genes showed that gene ATM was mutually exclusive from MSH6. We conducted a further case-control study in different subtypes of lung cancer and the results described 14 mutations associated with adenocarcinoma, 9 with squamous cell carcinoma, and 4 with small cell lung cancer. These variants were novel de-novo germline mutations in lung cancer. Particularly, rs3864017 in FANCD2 showed a protective effect of lung adenocarcinoma for carriers (OR = 0.146, 95 % CI = 0.052∼0.405, P_adjusted = 3.37 × 10⁻⁴).Conclusions18 candidate mutations might alter the risk of lung cancer in the Han Chinese population, including polymorphisms rs3864017(FANCD2), rs55740729(MSH6) and 16 rare variants. The underlying mechanisms of candidate genes in lung cancer remain unclear and we suggest more functional studies on exploring how these genes affect the risk of lung cancer.     

Rare and common variants in the Apolipoprotein E gene in healthy oldest old

Apolipoprotein E (APOE) alleles are associated with longevity in genome-wide scans, with ε4 correlated with shorter life, and ε2 with longer life, than ε3. We hypothesized that rare APOE variants with large individual effects might also contribute to long-term good health. The APOE exons and promoter were resequenced in DNA samples from 376 healthy oldest old aged ≥85yrs with no self-reported history of cancer, cardiovascular disease, diabetes, major pulmonary disease or Alzheimer disease (“Super-Seniors”) and 376 population-based controls aged 41–54. Forty variants were observed: 32 were rare (minor allele frequency <2%); 9 were nonsynonymous. Controls were more likely to have an ε4 allele (Pearson χ² = 6.61, p = 0.04). Among the Super-Seniors, APOE allele status was not associated with body mass index or Mini Mental State Examination score. There was no excess of rare APOE variants in healthy oldest old compared with midlife controls, or vice-versa; however, this does not rule out an effect of some variants on ApoE function. Our findings were consistent with ε4 being a risk factor for early mortality.     

Testing rare variants for association with diseases: a Bayesian marker selection approach

It has been a research focus to uncover the genetic determination of complex diseases caused by rare variants. As the vast majority of genomic variants represent background variation, highlighting potentially causal mutations through a weighting scheme is critical to the success of association studies aimed at identifying rare variants. In this study, we propose a novel Bayesian marker selection approach to perform a weighting-based association test. In this approach, an individual association signal and its direction are used to weight variants. In addition, the predicted biological function of variants is taken as prior information to direct the selection of likely causal variants. Simulation studies show that the proposed method has improved power over several existing methods in certain conditions. Analyses of two empirical datasets demonstrate its applicability.