The role of TxnRd2 in cortical circuit formation

TxnRd2 在皮质回路形成中的作用

基本信息

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
项目类别：
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

项目摘要

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）：线粒体氧化还原失衡和抗氧化防御能力下降——细胞维持细胞呼吸产生的自由基和酶促自由基解毒之间稳态的能力下降——可能伴随神经精神疾病患者皮质回路组织和功能的改变。然而，尚不清楚皮质回路发育过程中抗氧化防御能力下降和活性氧积累（ROS）是否会导致异常回路形成及其后果。 22q11 缺失综合征 (22q11DS) 患者比其他人群更容易患精神疾病；因此，22q11DS 被建议作为研究神经精神疾病的神经发育起源的模型。位于 22q11DS 中常见缺失区域的基因中，大约四分之一的基因编码定位于线粒体的蛋白质。我建议描述 22q11DS 小鼠模型中由于线粒体功能改变而产生的皮质神经元发育能力的变化，并确定这些变化如何影响回路形成。在 22q11 线粒体基因中，硫氧还蛋白还原酶 (TxnRd2) 在皮质回路分化期间表达最大，编码主要线粒体 H2O2 清除剂。因此，我将研究 TxnRd2 清除活性被破坏如何影响线粒体抗氧化防御并改变皮质神经元发育。我将验证以下假设：由于 TxnRd2 剂量减少，神经元发育后期线粒体抗氧化防御能力减弱，从而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，将使用诱导型 Cre 重组酶系统 (Cux2GFP-Cre) 在发育中的皮质投射神经元中专门生成 TxnRd2 等位基因突变系列。将分析神经元生长、分化和细胞器分布的完整性，以评估皮质神经元参与正常回路发育的能力的变化。 ROS 代谢将在 TxnRd2 耗尽的神经元中得到进一步操纵，将抗氧化防御与单个神经元构建回路的能力联系起来。我的研究将确定由于抗氧化防御减弱而导致线粒体 ROS 积累对神经元完整性的影响，并将确定锥体神经元分化改变在 22q11DS 回路形成中的作用。具有基因控制的酶抗氧化防御的同质神经元群体允许比较具有相同代谢需求的细胞中氧化还原平衡的调节，并分析改变的神经元能力以实现最佳皮质回路发育。我的数据将确定抗氧化防御在单个神经元构建回路的能力中的作用，并将深入了解氧化还原失衡在各种行为障碍中异常回路连接中的作用。