Contributions of Astrocyte Kir4.1/5.1 Channels to Disordered Breathing in Rett Syndrome

星形胶质细胞 Kir4.1/5.1 通道对 Rett 综合征呼吸障碍的影响

• 批准号: 10606795
• 负责人: Monica Strain
• 金额: $ 4.47万
• 依托单位: UNIVERSITY OF CONNECTICUT STORRS
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-06 至 2027-01-05
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10606795
• 关键词: Affect; Animal Model; Animals; Astrocytes; Behavior; Brain; Brain Stem; Breathing; Carbon Dioxide; Cell Nucleus; Cessation of life; Data; Disease; Electrophysiology (science); Failure; Future; Genes; Genotype; Goals; Homeostasis; In Vitro; Link; Mediating; Membrane Potentials; Methyl-CpG-Binding Protein 2; Molecular; Mus; Mutation; Neurodevelopmental Disorder; Neurons; Online Mendelian Inheritance In Man; Patients; Phenotype; Positioning Attribute; Process; Quality of life; Reflex action; Regulation; Research Personnel; Respiration Disorders; Rett Syndrome; Role; Science; Seizures; Site; Slice; Symptoms; Testing; Tissues; Training; Wakefulness; Whole Body Plethysmography; Work; autistic behaviour; comorbidity; extracellular; human model; insight; loss of function mutation; mortality; mouse model; premature; respiratory; response; targeted treatment; training opportunity

SUMMARY Rett syndrome (RTT) (OMIM #312750) is a severe X-linked neurodevelopmental disorder caused by mutations in the methyl-CpG-binding protein 2 (MECP2). Although RTT patients suffer from many co-morbid phenotypes, wake disordered breathing has a major negative impact quality of life and is associated with high mortality rate. Evidence from mouse models of RTT suggest disordered breathing results in part from a disrupted ability to regulate breathing in response to changes in tissue CO2/H+ (i.e., central chemoreflex). The retrotrapezoid nucleus (RTN) is an important site of chemoreception, neurons and astrocytes in this region sense changes in CO2/H+ to regulate breathing. Previous work identifies heteromeric Kir4.1/5.1 channels as key determinants of RTN astrocyte CO2/H+ chemosensitivity. However, homomeric Kir4.1 and heteromeric Kir4.1/5.1 are differentially CO2/H+ sensitive and regulate divergent astrocyte processes including membrane potential and clearance of neuronally released extracellular K+, and it is not clear which of these mechanisms contributes to RTN chemoreception and disordered breathing in RTT. Previous work from my sponsors group showed that MeCP2 deficient mice have reduced levels of both Kir4.1 and 5.1 channels, diminished astrocytic Kir4.1 mediated currents and dysregulated extracellular K+. Preliminary data also show that global deletion of Kir4.1 from astrocytes blunts the ventilatory response to CO2, while re-expression of Kir4.1 specifically in RTN astrocytes rescued this respiratory phenotype. Based on this, I hypothesize that MeCP2 deficiency results in loss of Kir4.1/5.1 and compromised astrocyte chemoreception that contributes to disordered breathing in RTT. To explore this possibility, I will test the following two Specific Aims: 1) Determine roles of astrocyte Kir4.1 containing channels in RTN chemoreception in vitro; and 2) Identify differential roles of Kir4.1 and Kir5.1 channels in the control of breathing in RTT. Understanding how Kir4.1 and Kir5.1 contribute to RTN chemoreception and disordered breathing may provide mechanistic insight for targeted treatment of disordered breathing in RTT. This work will also provide valuable training opportunities in molecular, cellular and whole- animal approaches that will prepare me for a successful future in science.

摘要 雷特综合征(RTT)(OMIM#312750)是一种由突变引起的严重的X连锁神经发育障碍 在甲基CpG结合蛋白2(MECP2)中。尽管RTT患者患有许多共病表型， 清醒呼吸障碍对生活质量有很大的负面影响，并与高死亡率相关。 来自RTT小鼠模型的证据表明，呼吸紊乱的部分原因是 调节呼吸以应对组织中CO2/H+的变化(即中枢化学反射)。后梯形 核团(RTN)是化学感受的重要部位，神经元和星形胶质细胞在该区域感觉变化 CO2/H+调节呼吸。以前的工作发现异构体Kir4.1/5.1通道是 RTN星形胶质细胞对CO2/H+的化疗敏感性。然而，同聚体Kir4.1和异构体Kir4.1/5.1是 对CO2/H+的不同敏感和调节星形胶质细胞的分化过程，包括膜电位和 清除神经元释放的细胞外K+，目前尚不清楚这些机制中的哪一种参与了 RTT中的RTN化学感受和呼吸障碍。我的赞助商小组之前的工作表明 MeCP2缺陷小鼠的Kir4.1和5.1通道水平均降低，星形胶质细胞Kir4.1表达减弱 介导的电流和细胞外K+的失调。初步数据还显示，Kir4.1在全球范围内缺失 当Kir4.1在RTN中特异性地重新表达时，星形胶质细胞中的Kir4.1表达减弱了对CO2的通气性反应 星形胶质细胞挽救了这种呼吸表型。在此基础上，我假设MeCP2缺乏会导致 Kir4.1/5.1丢失和星形胶质细胞化学接收受损导致呼吸障碍 RTT.为了探索这种可能性，我将测试以下两个具体目标：1)确定星形胶质细胞的角色 KIR4.1在体外RTN化学感受中的作用；2)鉴定Kir4.1和Kir5.1的不同作用 RTT中控制呼吸的通道。了解Kir4.1和Kir5.1如何促进RTN 化学感受和呼吸障碍可能为定向治疗障碍提供机械性洞察力 吸气RTT。这项工作还将在分子、细胞和整体方面提供宝贵的培训机会。 动物方法，这将为我在科学上的成功未来做好准备。