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; 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.

概括 RETT综合征（RTT）（OMIM＃312750）是由突变引起的严重X连锁神经发育障碍 在甲基-CPG结合蛋白2（MECP2）中。尽管RTT患者患有许多合并表型，但 唤醒失调的呼吸具有重大的负面影响生活质量，并且与高死亡率相关。 RTT小鼠模型的证据表明，呼吸无序的结果部分是由于破坏的能力而导致的 根据组织CO2/H+的变化（即中央化学反射）的变化来调节呼吸。逆转肌曲霉 核（RTN）是化学感受，神经元和星形胶质细胞的重要部位 CO2/H+调节呼吸。以前的工作将异元Kir4.1/5.1频道识别为关键决定因素 RTN星形胶质细胞CO2/H+化学敏感性。但是，同源物kir4.1和异构体Kir4.1/5.1为 差异化CO2/H+敏感并调节不同的星形胶质细胞过程，包括膜电位和 神经释放细胞外K+的清除率，尚不清楚这些机制中的哪些有助于 RTN化学感受和RTT中的呼吸无序。我的赞助商小组的先前工作表明 MECP2缺乏小鼠的Kir4.1和5.1通道的水平降低，星形细胞Kir4.1降低 介导的电流和细胞外K+失调。初步数据还表明，kir4.1的全球删除 从星形胶质细胞钝化对CO2的通气反应，而Kir4.1的重新表达在RTN中。 星形胶质细胞营救了这种呼吸表型。基于此，我假设MECP2缺乏导致 Kir4.1/5.1的丧失和星形胶质细胞化学感受，导致呼吸无序 RTT。为了探讨这种可能性，我将测试以下两个特定目的：1）确定星形胶质细胞的作用 Kir4.1体外含有RTN化学感受的通道； 2）确定Kir4.1和Kir5.1的差异作用 控制RTT呼吸的通道。了解Kir4.1和Kir5.1如何有助于RTN 化学感受和呼吸无序可能为靶向治疗无序治疗提供机械洞察力 RTT呼吸。这项工作还将为分子，细胞和整体提供宝贵的培训机会 动物方法将使我在科学方面的成功未来做好准备。