The role of TxnRd2 in cortical circuit formation

TxnRd2 在皮质回路形成中的作用

• 批准号: 8786153
• 负责人: Alejandra Fernandez
• 金额: $ 3.2万
• 依托单位: GEORGE WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8786153
• 关键词: 22q11; 22q11 Deletion Syndrome; Activities of Daily Living; Affect; Antioxidants; Apoptosis; Behavior Disorders; Biological Assay; Brain; Cell Respiration; Cells; Data; Development; Disease; Drug Metabolic Detoxication; Equilibrium; Free Radical Formation; Free Radicals; Functional disorder; Genes; Genotype; Goals; Growth; Homeostasis; Hydrogen Peroxide; In Vitro; Individual; Length; Link; Maintenance; Measures; Mental disorders; Metabolic; Metabolism; Mitochondria; Modeling; Morphology; Mutation; Neurites; Neuronal Differentiation; Neurons; Organelles; Oxidation-Reduction; Oxidative Stress; Patients; Phenotype; Play; Population; Proteins; Psychopathology; Reactive Oxygen Species; Regulation; Rest; Role; Series; Staging; Study models; Synapses; System; Testing; Transgenic Mice; axon growth; caspase-3; cell preparation; density; dosage; hippocampal pyramidal neuron; insight; mouse model; neuron development; neuronal growth; neuropsychiatry; public health relevance; recombinase; research study; synaptogenesis; thioredoxin reductase; trafficking

DESCRIPTION (provided by applicant): Mitochondrial redox imbalance and decreased antioxidant defense-a decline in a cell's ability to maintain homeostasis between free radicals generated from cellular respiration and enzymatic free radical detoxification-may accompany altered cortical circuit organization and function in patients with neuropsychiatric disorders. However, it is unknown if decreased antioxidant defense and reactive oxygen species accumulation (ROS) during development of cortical circuits contributes to aberrant circuit formation and its consequences. Patients with 22q11 deletion syndrome (22q11DS) are more susceptible to psychiatric disorders than the rest of the population; therefore, 22q11DS has been suggested as a model for studying the neurodevelopmental origins of neuropsychiatric disorders. About one quarter of the genes located in the commonly deleted region in the 22q11DS encode proteins that localize to mitochondria. I propose to characterize changes in the developmental capacity of cortical neurons that develop due to altered mitochondrial function in mouse models of 22q11DS and determine how these changes could compromise circuit formation. Among 22q11 mitochondrial genes, thioredoxin reductase (TxnRd2), maximally expressed during cortical circuit differentiation, encodes a primary mitochondrial H2O2 scavenger. Thus, I will investigate how disrupted scavenging activity of TxnRd2 impacts mitochondrial antioxidant defense and alters cortical neuron development. I will test the hypothesis that diminished mitochondrial antioxidant defense during late stages of neuronal development, due to diminished dosage of TxnRd2, disrupts the capacity of cortical neurons to establish optimal connections. To test this hypothesis, an allelic series of TxnRd2 mutations will be generated specifically in developing cortical projection neurons, using an inducible Cre-recombinase system (Cux2GFP-Cre). Integrity of neuronal growth, differentiation and organelle distribution will be analyzed to evaluate changes in the capacity of cortical neurons to engage in normal circuit development. ROS metabolism will be further manipulated in TxnRd2-depleted neurons to link antioxidant defense to the capacity of individual neurons to build circuits. My studies will define the effects of mitochondrial accumulation of ROS due to diminished antioxidant defense on neuronal integrity, and will establish the role of altered pyramidal neuron differentiation in the formation of circuits in 22q11DS. A homogenous population of neurons with genetically controlled enzymatic antioxidant defense permit comparison of regulation of redox balance in cells with equal metabolic demand, and analysis of altered neuronal capacity for optimal cortical circuit development. My data will establish a role for antioxidant defense in the capacity of individual neurons to build circuits and will provide insight into the role of redox imbalance in aberrant circuit connectivity in a wide range of behavioral disorders.

描述（由申请人提供）：线粒体氧化还原不平衡和抗氧化剂防御的降低 - 细胞在细胞中维持由细胞呼吸和酶自由基解毒产生的自由基之间维持稳态的能力，并伴随着具有神经精神疾病的患者的皮质反理组织和功能。但是，在皮质回路发展过程中，抗氧化剂防御和活性氧的积累（ROS）是否尚不清楚，导致了异常的回路形成及其后果。与其他人群相比，患有22q11缺失综合征（22q11ds）的患者更容易患精神疾病。因此，已建议将22q11ds作为研究神经精神疾病的神经发育起源的模型。大约四分之一的基因位于22q11ds中常见区域中的基因编码定位于线粒体的蛋白质。我建议表征由于22q11ds小鼠模型中线粒体功能改变而发展的皮质神经元的发育能力的变化，并确定这些变化如何损害电路的形成。在22q11线粒体基因中，在皮质回路分化期间最大表达的硫氧还蛋白还原酶（TXNRD2）编码了主要的线粒体H2O2清除剂。因此，我将研究TXNRD2的清除活性如何影响线粒体抗氧化剂防御，并改变皮质神经元的发育。我将检验以下假设，即由于TXNRD2的剂量降低，在神经元发育后期降低了线粒体抗氧化剂防御，破坏了皮质神经元建立最佳连接的能力。为了检验这一假设，使用诱导的CRE - 成分酶系统（CUX2GFP-CRE），将专门在开发皮质投射神经元中专门生成一系列等位基因TXNRD2突变。神经元生长，分化和细胞器分布的完整性将进行分析，以评估皮质神经元参与正常电路发育能力的变化。 ROS代谢将在txnRD2耗尽的神经元中进一步操纵，以将抗氧化剂防御与单个神经元建立电路的能力联系起来。我的研究将定义由于抗氧化剂防御对神经元完整性的减少而导致的线粒体积累的影响，并将确定锥体神经元分化改变在22q11ds中回路中的作用。具有遗传控制的酶促抗氧化剂防御的神经元的同质群体允许比较具有相等代谢需求的细胞中氧化还原平衡的调节，并分析神经元能力改变的神经元能力的最佳皮质回路发育。我的数据将在单个神经元建立电路的能力上为抗氧化剂防御发挥作用，并将洞悉氧化还原不平衡在多种行为障碍中异常电路连通性中的作用。