Cross-Species Genetic and Epigenetic Studies of Stress Response and Reward

应激反应和奖励的跨物种遗传学和表观遗传学研究

• 批准号: 8746468
• 负责人: Christina Barr
• 金额: $ 95.94万
• 依托单位: NATIONAL INSTITUTE ON ALCOHOL ABUSE AND ALCOHOLISM
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8746468
• 关键词: Affect; Affinity; Age; Aggressive behavior; Alcohol abuse; Alcohol consumption; Alcohols; Alleles; Amino Acid Substitution; Animals; Anti-Anxiety Agents; Anxiety; Archives; Area; Behavior; Behavior Disorders; Behavioral; Brain; Brain region; Canis familiaris; Catarrhine; Cebidae; Cercopithecidae; Cercopithecus tantalus; Characteristics; Code; DNA; DRD4 gene; Data; Detection; Disease; Dolphins; Dopamine; Elements; Endorphins; Epigenetic Process; Equilibrium; Equus caballus; Erythrocebus patas; Esthesia; Euphoria; European; Evolution; Exhibits; Exons; Family Felidae; Frameshift Mutation; Frequencies; Fright; Gene Expression; Genes; Genetic; Genetic Polymorphism; Genetic Variation; Genomics; Haplotypes; Human; Human Genetics; Impulsivity; Incidence; Individual Differences; Investigation; Length; Ligand Binding Domain; Ligands; Link; Location; Macaca; Macaca mulatta; Measures; Mental Depression; Mental disorders; Mission; Modeling; Names; National Institute on Alcohol Abuse and Alcoholism; Neuropeptides; Opioid; Oxytocin; Oxytocin Receptor; Pan Genus; Pattern; Physical aggression; Pongidae; Primates; Process; Psychopathology; RNA Splicing; Raccoons; Reagent; Receptor Gene; Regulation; Rewards; Risk; Risk Factors; Rodent; Role; Sampling; Site; Social Interaction; Stress; Structure; System; Tandem Repeat Sequences; Taxon; Temperament; Terminator Codon; Therapeutic Agents; Tissues; Translating; Tribes; Ursidae Family; Variant; Whole Blood; addiction; alcohol related problem; alcohol use disorder; base; behavioral genomics; biological adaptation to stress; comparative; deep sequencing; endophenotype; exome; exome sequencing; gain of function; gene environment interaction; genetic variant; genome sequencing; insertion/deletion mutation; interest; loss of function; neurogenetics; neurotransmission; nonhuman primate; receptor; response; sample fixation; screening; sex; social; social attachment; social organization; species difference; stress related disorder; trait; vervet

Identification of Genetic Variation using Massively Paralleled Sequencing This year, we sequenced the exomes of rhesus macaque subjects that were selected based on variation in temperament. One big advantage of using this approach is that DNA extracted whole blood can be used without the need for extracting DNA from the tissue of interest. Whole Exome Sequencing allows for the capture of large insertion/deletions and SNPs, and is best for Mendelian traits where variation is highly penetrant and either non-synonomous or frameshift. Drawbacks to WES include the inability to interrogate sequence sites that are not currently recognized as genes, control/regulatory sequences, structural variants such as translocations and inversions, splice-site variation, and exonic repeats. However, due to exome enrichment and the resulting deep sequencing coverage, the enhanced coding-region interrogation WES provides will allow for the sensitive detection of variants at those sites that are targeted. While there are no commercially available reagents for performing whole exome sequencing in nonhuman primates, a human whole exome platform is available. Given that there would likely be more purifying selection in coding regions and, therefore, less interspecific variation, we proposed using a human exome capture and sequencing kit for performing exome sequencing in rhesus macaques that differed in impulsivity and aggression. This approach was successful, and we identified many snps, including 391 missense variants, 23 stop codon snps, and 4 frameshift mutations. Of these, 58 variants were in genes in which variation is proposed to moderate addiction risk in humans. Whether these variants predict individual differences in alcohol drinking and related behaviors in rhesus macaques is currently under investigation. In certain instances, genetic variants that are functionally similar or orthologous to those that increase risk for human psychiatric disorders are maintained across primate species. We have identified several examples of this phenomenon in performing studies in rhesus macaques in order to model how genetic variation moderates risk for developing psychopathology. Some of these studies have suggested there to be convergent evolution or allelic variants being maintained by selection in both species. We may use naturally occurring genetic variation to look at not only within-species differences in vulnerability to behavioral disorders, but also to examine how genetic variation may alter traits in closely related species. Macaque species, all of which exhibit the same core elements of social organization and demographic structure, differ in characteristic patterns of stress reactivity, temperament and social interaction. We are currently performing whole exome sequencing a higher number of primate species, including the greater and lesser apes, and Old World monkeys (with an enriched sampling of Macaca) and the New World monkeys. One other area of interest for the study of genetic factors that contribute to addiction vulnerability is the genetics underlying domestication in animals.At its most basic, domestication is a suite of heritable traits affecting behavior. There are intriguing phenotypic commonalities among domesticates. Most important among these traits, and the only one common to all domesticates, is the ability to coexist with humans. The systems that likely permitted early domestication range from those involving fear and impulse control to those involving reward and sociality. Genetics contributing to such traits are likely to be relevant to human psychiatric illness and, in particular, the addictions. We have sequenced the genomes of domestic and European Wildcats, two species of felids that differ only in their behavior. Whether genetic variation that might underlie behavioral differences in these species is present is currently under investigation. Neurogenetics of Stress Response and Reward Sensitivity We have been studying how spontaneous genetic variation that influences reward sensitivity, and which could be adaptive in certain contexts, may also increase risk for alcohol related problems. In both humans and rhesus macaques, there are polymorphisms in the mu-opioid receptor gene (OPRM1) that influence affinity of the receptor for its endogenous ligand, -Endorphin. We and others have shown that these polymorphisms predict increased alcohol-induced euphoria and decreased stress response, suggesting them to have gain-of-function roles. We also have demonstrated it to relate to individual differences in response to natural rewards, as shown by measures of both reward bias in humans (and social attachment in both human and macaque. Recently, we have been screening this gene for variation across species in order to look for signs of selection and to determine whether functional variation that predicts species might be present. Of interest, we found a variant that produces a non-neutral amino acid substitution in the OPRM1 receptors ligand-binding domain (Asp12>Lys12). Among the Old World Monkey species that were screened (N = 17) this fixed difference was observed in all 5 species in the Cercopthecini tribe (which includes Patas monkeys and vervets, to name a few), but this allele was not observed outside of this tribe. Field observations of Vervet and Patas suggest they are reward-sensitive and more susceptible to stress compared to other OWMs. Our data suggest that an OPRM1 variant arose and went to fixation after the divergence of Cercopthecini from Papionini. They further support data showing that polymorphism at OPRM1 contributes to behavioral variation in primates. Dopamine neurotransmission underlies many reward-dependent and reinforcing processes. Tandem repeats in the third exon of the dopamine receptor D4 gene (DRD4) exist across a variety of animal species (humans, vervets, dogs, dolphins, bears, raccoons, horses, and chimpanzees). Some species, including macaque species, exhibit variation in the number of repeats present, with various alleles differing in frequencies across species. In humans, the DRD4 7-repeat allele (7R) reduces efficacy of the receptor and is linked with traits such as sensation seeking. This has been replicated in vervet monkeys, in which a DRD4 length variant was also observed. Of interest, in the dog, which has been subject to intense artificial selection, a repeat polymorphism predicts social impulsivity and activity-impulsivity endophenotypes. We recently identified 4R, 5R, 6R, and 7R alleles in a colony of rhesus macaques. Compared to the ancestral allele (4R), the loss-of-function 7R allele predicted increased incidence of physical aggression toward an unknown age- and sex-matched conspecific. One system of potential relevance to the addictions via its effects on anxiety and reward is the oxytocin system. We screened the rhesus OXTR gene and identified 17 SNPs, including 4 non-synonymous SNPs in the first exon for the rhesus Oxytocin receptor gene (OXYR). This is a location at which there is high interspecific conservation yet high frequencies of non-synonymous SNPs in humans as well. Among these, some of them are conserved across primate taxa, suggesting that they have been maintained by selection. We also found there to be ancient polymorphisms maintained in humans and the existence of alternative haplotypes within this region indicating that human variation is being maintained by balancing selection. Oxytocin is a neuropeptide that produces affiliative, amnesic and anxiolytic affects. Given its roles in some of these processes, it has been proposed as a potential therapeutic agent for the treatment of anxiety and stress-related disorders, including the addictions.Functional variation that influences oxytocin system function may also be a good candidate for performing GxE studies.

使用大量平行的测序鉴定遗传变异 今年，我们测序了基于气质变化选择的恒河猕猴的外部。使用这种方法的一个重要优点是，可以使用DNA提取的全血而无需从感兴趣的组织中提取DNA。整个外显子组测序允许捕获大型插入/缺失和SNP，并且最适合Mendelian性状，在变化高度渗透性且非同义或移率的情况下。 WES的缺点包括无法询问序列位点，这些位点目前尚未被识别为基因，对照/调节序列，结构变体，例如易位和反转，剪接位点变化和外显子重复序列。但是，由于外显子元素富集和所得深度测序覆盖范围，增强的编码区域询问WES提供了允许在针对目标的那些站点上对变体的敏感检测。 尽管没有用于在非人类灵长类动物中执行整个外显子组测序的市售试剂，但可以使用人类的整个外显型平台。鉴于在编码区域中可能会有更多的净化选择，因此，种间变化较少，我们提出了使用人类外显子组捕获和测序试剂盒在恒河猕猴中进行外显子组测序，在冲动性和侵略性上有所不同。这种方法成功了，我们确定了许多SNP，包括391个错义变体，23个终止密码子SNP和4个移码突变。其中，有58种变体是在基因中提出的变异，以使人类中度成瘾风险中等。这些变体目前正在研究这些变体是否预测恒河猕猴中饮酒和相关行为的个体差异。 在某些情况下，在功能上与增加人类精神疾病风险的遗传变异型在灵长类动物中保持了。我们已经在恒河猕猴进行研究中确定了这种现象的几个例子，以模拟遗传变异如何缓和心理病理学的风险。其中一些研究表明，在这两个物种的选择中都存在收敛的进化或等位基因变体。我们可能会使用自然存在的遗传变异来研究行为障碍脆弱性内物种内部差异，而且还研究了遗传变异如何改变密切相关的物种中的性状。猕猴的物种，所有这些物种都表现出社会组织和人口结构的相同核心要素，在压力反应性，气质和社会互动的特征模式上有所不同。目前，我们正在进行整个外显子组测序，包括更大的灵长类动物，包括大量和小的猿类，以及旧世界的猴子（具有丰富的Macaca采样）和新世界的猴子。 研究造成成瘾脆弱性的遗传因素研究的另一个感兴趣领域是动物中的基础遗传学。它最基本的驯化是影响行为的遗传性状。家人之间有有趣的表型共同点。在这些特征中，最重要的是，所有家属共同的特征是与人共存的能力。可能允许早期驯化的系统从涉及恐惧和冲动控制的系统到涉及奖励和社会性的系统。造成这种特征的遗传学可能与人类精神病，尤其是上瘾有关。我们已经对国内和欧洲野猫的基因组进行了测序，这是两种仅在行为上有所不同的FELID。目前正在研究这些物种中可能存在行为差异的遗传变异。 压力反应和奖励灵敏度的神经遗传学 我们一直在研究如何影响奖励灵敏度的自发遗传变异，并且在某些情况下可能会适应性，也可能会增加与酒精相关的问题的风险。在人类和恒河猕猴中，MU-阿片受体基因（OPRM1）中都有多态性，会影响受体对其内源配体的亲和力 - 内源 - 内啡肽。我们和其他人已经表明，这些多态性预测酒精引起的欣快感和压力反应减少，这表明它们具有功能的作用。我们还证明了它与对自然奖励的响应响应的个体差异有关，如人类奖励偏见的衡量所示（以及人和猕猴的社会依恋。筛选的旧世界猴子中的配体结合域（ASP12> lys12）在Cercopthecini部落的所有5种中都观察到了这种固定差异（其中包括Patas猴子和Vervets，其中几个都不是在此范围内观察到的。 OWMS。他们进一步支持数据，表明OPRM1的多态性有助于灵长类动物的行为变化。 多巴胺神经传递是许多奖励依赖和加强过程的基础。多巴胺受体D4基因（DRD4）的第三个外显子中的串联重复存在于多种动物物种（人类，天文，狗，海豚，熊，浣熊，马和黑猩猩）中。某些物种，包括猕猴物种，在存在的重复数量上显示出差异，各种等位基因的频率各不相同。 在人类中，DRD4 7-重复等位基因（7R）降低了受体的功效，并与寻求感觉等性状有关。这已在Vervet猴子中复制，其中还观察到DRD4长度变体。感兴趣的是，在狗中受到强烈人工选择的影响，重复多态性可以预测社会冲动性和活动冲动性内表型。我们最近在恒河猕猴的殖民地中确定了4R，5R，6R和7R等位基因。与祖先等位基因（4R）相比，功能丧失的7R等位基因预测，身体侵略的发生率增加了，对年龄和性别匹配的异形。 催产素系统是通过其对焦虑和奖励的影响与成瘾有关的一种潜在相关性的系统。我们筛选了Oxtr基因，并鉴定了17个SNP，其中包括恒河氧蛋白受体基因（Oxyr）的第一个外显子中的4个非同义SNP。这是人类中非同义性SNP的种间保护性较高而高频的位置。其中，其中一些是在灵长类动物分类单元中保守的，这表明它们是通过选择维护的。我们还发现，人类中存在古老的多态性，并且在该区域内存在替代单倍型，这表明通过平衡选择可以维持人类的变异。催产素是一种神经肽，会产生从属，健忘和抗焦虑作用。鉴于其在其中一些过程中的作用，已被提出是治疗焦虑和与压力有关的疾病的潜在治疗剂，包括成瘾。影响催产素系统功能的功能变化也可能是进行GXE研究的良好候选者。