Biological Characterization of Genetic Mechanisms in Neuropsychiatric Disorders

神经精神疾病遗传机制的生物学特征

• 批准号: 7594625
• 负责人: Daniel Weinberger
• 金额: $ 75.45万
• 依托单位: NATIONAL INSTITUTE OF MENTAL HEALTH
• 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/7594625
• 关键词: AKT1 gene; Accounting; Adult; Affect; Alleles; Animals; Antipsychotic Agents; Attention; Autopsy; Behavior; Biological; Biological Assay; Biology; Bipolar Disorder; Brain; Brain region; Catechols; Cell Differentiation process; Cell Line; Cell model; Cells; Chromosome Mapping; Clinical; Cognition; Cognitive; Collaborations; Complex; Coupling; DARPP 32; DISC1 protein; DLG4 gene; DNA; DNA biosynthesis; DRD2 gene; Data; Data Set; Development; Diagnosis; Disease; Dopamine; Emotional; Emotions; Environment; Equilibrium; ErbB4 gene; Europe; Event; Exons; FGF20 gene; Family; Functional disorder; Gene Expression; Generations; Genes; Genetic; Genetic Polymorphism; Genetic Variation; Genome; Genotype; Haplotypes; Hereditary Disease; Hippocampus (Brain); Human; Image; Incidence; Individual; Individual Differences; Institutes; Interview; Learning; Life; Link; Major Depressive Disorder; Malignant Neoplasms; Mammary Neoplasms; Mediating; Memory; Mental disorders; Methyltransferase; Mission; Modification; Molecular; Molecular Target; Motor Activity; Mus; Mutation; NRG1 gene; Neuregulin 1; Neurobiology; Neuroblastoma; Neurons; Neuropeptides; Neurosciences; Neurotransmitters; PLAB Protein; Pathogenesis; Pathway interactions; Patients; Pattern; Performance; Phenotype; Play; Prefrontal Cortex; Prevention; Process; Property; Protein Isoforms; Protein Overexpression; Proteins; Psychotic Disorders; RNA Splicing; Regulation; Relative (related person); Research; Research Personnel; Resources; Risk; Role; Schizophrenia; Scientist; Short-Term Memory; Signal Pathway; Signal Transduction; Site; Specificity; Staging; Stimulus; Stress; Structure; Susceptibility Gene; System; Testing; Therapeutic; Tissues; Transcript; Transcriptional Regulation; Translating; United States National Institutes of Health; Variant; Vision; Work; age group; base; brain morphology; case control; cell type; clinical Diagnosis; dopamine system; enzyme activity; fetal; gene environment interaction; gene function; gene interaction; genetic association; genetic variant; human FGF20 protein; mRNA Expression; memory recognition; methionylmethionine; migration; molecular pathology; neonate; neurobiological mechanism; neurogenesis; neuroimaging; neuropsychiatry; neuropsychological; neurotransmission; novel; pituitary adenylate cyclase activating polypeptide; postnatal; programs; promoter; protein expression; receptor; synaptogenesis; trait; tumorigenesis

Genes are major contributors to many psychiatric diseases, but their mechanisms of action have long seemed elusive. To date, we have evidence of association with schizophrenia in our family datasets of at least the following genes: COMT, DTNBP1, MUTED, EAA1, MRDS1, GAD1, DISC1, FEZ1, CITRON, NDE1, NRG1, PIK3d, ErbB4, DLG4, LIS1, MHTFR, DRD2, CAPON, PPP1R1B, DAARP, GRM3, CHRNA7, KCNH2, SREB2, PRODH, CAMKIIa, AKT1, FGF20, RELN1, and RCCX. Our dataset consists of individuals from over 750 families and case/control datasets of over 650. The unique aspects of our dataset, which may explain the strength of the genetic associations that have emerged, is that every subject, both cases and controls, are evaluated extensively with structured on sight interviews by the same clinicians who have worked together on this project for over ten years. As characterization of single genetic variants rapidly proceeds, research increasingly turns to dissecting gene-gene and gene-environment interactions. Our strategy for characterizing and mapping gene effects in brain with cognitive and neuroimaging assays enables us to better define intermediate phenotypes. Here we outline recent advances of linking genes to structural and functional variation in brain systems related to cognition and emotion. One study examined genotype effect of catechol-o-methyltransferase (COMT) Val158Met on corticolimbic circuitry and functional connectivity. We found that Met/Met subjects had the ability to focus attention on relevant stimuli while inhibiting interference from other stimuli. This may be of great advantage during working memory (WM) task, but may have deleterious effects in environments with multiple stimuli requiring rapid and flexible processing. Another study evaluated COMT and GRM3 and examined their combined effects on dissociable components of the WM network. We found an epistatic interaction of these genes on the engagement of prefrontal cortex. GRM3 genotype was associated with inefficiency and altered prefrontal coupling on the background of COMT Val. As we know, abnormalities in dopamine (DA) neurotransmission contribute to psychiatric disorders. It has been shown that a network of brain regions is involved in performance of declarative and recognition memory tasks and this network, hippocampus and VLPFC, is modulated by DA. Regulation of DA signaling and neurotransmission is critically affected by COMT. We examined the effect of COMT Val158Met on function and coupling during recognition memory. There is compelling evidence that DA is an important modulator of hippocampal and prefrontal cortical interaction. This suggests that individual differences in responsivity and connectivity related to genetic modulation of DA, is a mechanism accounting for some individual differences in recognition memory performance. We also examined the effects of the PACAP gene on neurobiological traits related to risk for schizophrenia (SCZ). PACAP is a neuropeptide with neurotransmission modulating activity. We found an allele is overexpressed in patients showing an association with reduced hippocampal volume and poorer memory performance. We generated mice lacking the PACAP gene and observed abnormal behaviors, like elevated locomotor activity, which were reversed by treatment with an antipsychotic. These data suggest that alterations in PACAP signaling may contribute to the pathogenesis of SCZ. Our examination of transcripts, protein processing and expression has resulted in several findings. One study of DA- and cAMP-regulated phosphoprotein (DARPP-32) we identified a common haplotype, which predicts mRNA expression in postmortem human brain. This haplotype is associated with enhanced performance on several cognitive tests and imaging revealed an impact on neostriatal volume, activation, and functional connectivity of PFC. We use postmortem brain to focus on postnatal developmental changes. We examined COMT enzyme activity and protein expression in the PFC in 6 age groups of normals. We found a significant increase in COMT enzyme activity from neonate to adulthood which is paralleled by increases in protein expression. COMT protein expression is related to the Val158Met genotype. These increases may reflect changes in the PFC dopamine system and stresses the importance of COMT for PFC dopamine regulation during maturation. We also examined the DISC1 gene. DISC1 is the result of a balanced molecular translocation, which segregates with major mental disorders like SCZ, bipolar disorder and major depressive disorder (MDD). Our association study of DISC1 with MDD and SCZ found the risk allele, Cys704 associated with increased risk of developing MDD. Ser704Cys variation impacts brain morphology in normals and in primary neuronal culture, knockdown of cellular DISC1 protein resulted in suppression of ERK and Akt modification, whose signaling pathways are implicated in MDD. A possible biological mechanism of MDD is associated with lower biological activity on ERK signaling. Many human genes are known to produce more than one protein isoform through various molecular events. The use of multiple DNA replication start sites (promoters) is a frequent mechanism for generation of isoforms that provide tissue/cell type specificity, developmental-stage specificity, and allows for diverse functional properties of a gene. Neuregulin 1 (Nrg1) has nine alternative promoters. Genetic variations in promoters can contribute to genetic diseases by creating entirely new transcripts from any given gene. Such mechanisms may underlie the pathogenesis of complex diseases like SCZ. Recently, altered expression of a novel isoform (type 4) in the brain has been associated with schizo-related genetic variants. We isolated and characterized NRG1 type 4 DNA from adult and fetal human brain and identified a novel splice variant. We found a NRG1 protein representing a putative type 4 proprotein which is exclusively expressed in adult and fetal brain. Nrg1 type 4 expression is higher in the fetal brain and may have an important functional role during early brain development mediated through NRG1s effects on neurogenesis, neuronal migration, cell differentiation and synapse formation, and the regulation of neurotransmitter function. The fact that expression is brain-specific may be valuable in terms of possible therapeutics of NRG1 type 4 in SCZ. Nrg1 plays an important role in oncogenesis, and is overexpressed in various cancer tissues. However, we did not detect NRG1 type 4 in breast tumor and neuroblastoma cell lines. This absence, when juxtaposed to increased NRG1 type 4 associated with risk for SCZ, may contribute to the reduced incidence of cancer in patients SCZ and their relatives. This convergent pattern suggests that genetic regulation of type 4 may have a dual effect of protecting against cancer while increasing risk for SCZ. We have shown that type 4 represents a novel, translated, developmentally regulated, brain-specific isoform. We also show that a NRG1 promoter mutation, which impacts risk, is functional and selectively affects transcriptional levels of the type 4 isoform, providing a mechanism for the functional associations. Lastly, recent identification of NRG1 receptor, ErbB4 as a candidate SCZ risk gene, suggests that other molecules in the NRG1 pathway may also be involved. It has been shown that a molecular mechanism contributing to the genetic association of NRG1 with SCZ involves altered transcriptional regulation of a novel variant of the gene. We examined ErbB4 splice variant gene expression in hippocampus and DLPFC. ErbB4 splice patterns remain unaltered in hippocampus of SCZ, however we show an increase in expression of only the splice variant containing exons 16 and 26 in DLPFC in SCZ, suggesting that an ErbB4 receptor with exons 16 and 26 domains is preferentially upregulated in the disea

基因是许多精神病疾病的主要因素，但它们的作用机理长期以来似乎难以捉摸。 To date, we have evidence of association with schizophrenia in our family datasets of at least the following genes: COMT, DTNBP1, MUTED, EAA1, MRDS1, GAD1, DISC1, FEZ1, CITRON, NDE1, NRG1, PIK3d, ErbB4, DLG4, LIS1, MHTFR, DRD2, CAPON, PPP1R1B, DAARP, GRM3，CHRNA7，KCNH2，SREB2，PODH，CAMKIIA，AKT1，FGF20，RERN1和RCCX。我们的数据集由来自750多个家庭的个体以及650多个案例/控制数据集组成。我们数据集的独特方面可以解释出现了已经出现的遗传关联的强度，是，每个受试者（包括病例和对照）的每个受试者都经过与十多年来在此项目中共同进行的临床访谈的结构进行广泛评估。随着单个遗传变异的表征迅速进行，研究越来越多地转化为剖析基因基因和基因环境相互作用。我们用认知和神经影像学测定的大脑中表征和映射基因效应的策略使我们能够更好地定义中间表型。在这里，我们概述了将基因与与认知和情感有关的大脑系统中的结构和功能变化联系起来的最新进展。一项研究检查了Catechol-O-甲基转移酶（COMT）Val158MET对皮质胶质电路和功能连接性的基因型效应。我们发现，MET/MET受试者有能力将注意力集中在相关刺激上，同时抑制其他刺激的干扰。这在工作记忆任务（WM）任务期间可能具有很大的优势，但是在需要快速和灵活处理的多个刺激的环境中可能会产生有害影响。另一项研究评估了COMT和GRM3，并检查了它们对WM网络可分离组件的综合影响。我们发现这些基因在前额叶皮层的参与方面存在上皮相互作用。 GRM3基因型与COMT Val背景的效率低下和额叶耦合改变有关。众所周知，多巴胺（DA）神经传递的异常会导致精神疾病。已经表明，大脑区域网络参与声明性和识别记忆任务的性能，并且该网络Hippocampus和VLPFC由DA调节。 DA信号传导和神经传递的调节受到COMT的严重影响。我们检查了COMT Val158met对识别记忆过程中功能和耦合的影响。有令人信服的证据表明，DA是海马和额叶皮层相互作用的重要调节剂。这表明，与DA的遗传调制有关的响应性和连通性的个体差异是构成识别记忆表现某些个体差异的机制。我们还研究了PACAP基因对与精神分裂症风险（SCZ）有关的神经生物学特征的影响。 PACAP是一种神经传递调节活性的神经肽。我们发现，与海马体积减少和记忆力较差的患者相关的患者中过表达了等位基因。我们产生了缺乏PACAP基因并观察到的异常行为的小鼠，例如运动活性升高，通过抗精神病药的治疗逆转。这些数据表明，PACAP信号的改变可能有助于SCZ的发病机理。 我们对转录本，蛋白质加工和表达的检查导致了几个发现。一项针对DA-和cAMP调节的磷蛋白（DARPP-32）的研究确定了一种常见的单倍型，该单倍型预测了验尸后人脑中的mRNA表达。该单倍型与在几种认知测试上的增强性能有关，并且成像揭示了对新纹状体体积，激活和PFC功能连接性的影响。我们使用验尸大脑专注于产后发育变化。我们检查了6个年龄段的PFC中COMT酶活性和蛋白质表达。我们发现，从新生儿到成年的COMT酶活性显着增加，这与蛋白质表达的增加相似。 COMT蛋白表达与Val158MET基因型有关。这些增加可能反映了PFC多巴胺系统的变化，并强调了COMT在成熟过程中PFC多巴胺调节的重要性。我们还检查了Disc1基因。 Disc1是平衡分子易位的结果，该易位分离为SCZ，双相情感障碍和主要抑郁症（MDD）等主要精神障碍。我们与MDD和SCZ对DISC1的协会研究发现了风险等位基因，CYS704与增加MDD的风险有关。 Ser704Cys变异会影响脑形态和原发性神经元培养的脑形态，细胞盘蛋白的敲低导致ERK和AKT修饰的抑制，其信号传导途径与MDD有关。 MDD可能的生物学机制与ERK信号传导上的生物学活性较低有关。 已知许多人类基因通过各种分子事件产生多种蛋白质同工型。使用多个DNA复制起始位点（启动子）是一种经常生成的同工型的机制，可提供组织/细胞类型特异性，发育阶段特异性，并允许基因的功能性能多样化。 Neuregulin 1（NRG1）具有九个替代启动子。启动子的遗传变异可以通过从任何给定基因创建全新的成绩单来导致遗传疾病。这种机制可能是SCZ等复杂疾病的发病机理的基础。最近，大脑中新型同工型（4型）的表达改变与精神分裂相关的遗传变异有关。我们从成人和胎儿人脑中分离并表征了NRG1 4型DNA，并确定了一种新型的剪接变体。我们发现一种代表假定的4型普洛蛋白的NRG1蛋白，该蛋白在成人和胎儿大脑中仅表达。 NRG1 4型的表达在胎儿脑中较高，并且在通过NRG1S对神经发生，神经元迁移，细胞分化和突触形成以及神经递质功能的调节中介导的早期脑发育过程中可能具有重要的功能作用。在SCZ中NRG1 4型的可能的疗法方面，表达是大脑特异性的事实。 NRG1在肿瘤发生中起重要作用，并且在各种癌症组织中过表达。但是，我们没有在乳腺肿瘤和神经母细胞瘤细胞系中检测到NRG1 4型。当与SCZ风险相关的NRG1 4型4型NRG1并列时，这种缺失可能导致患者SCZ及其亲戚的癌症发病率降低。这种收敛模式表明，4型的遗传调节可能具有预防癌症的双重作用，同时增加了SCZ风险。我们已经表明，4型代表一种新颖的，翻译的，发育调控的，脑特异性的同工型。我们还表明，影响风险的NRG1启动子突变是功能性的，并且有选择地影响4类同工型的转录水平，从而为功能关联提供了机制。最后，最近对NRG1受体ERBB4为候选SCZ风险基因的鉴定表明，NRG1途径中的其他分子也可能涉及。已经表明，有助于NRG1与SCZ遗传关联的分子机制涉及该基因新颖变异的转录调节改变。我们检查了海马和DLPFC中的ERBB4剪接变异基因表达。 ERBB4剪接模式在SCZ的海马中保持不变，但是我们显示出SCZ中DLPFC中包含外显子16和26的剪接变体的表达增加，这表明具有外显子16和26域的ERBB4受体在DISEA中优先上调。