Imaging macroscopic cortical dynamics to understand sensorimotor dysfunction and recovery in a mouse model of Rett Syndrome

对宏观皮质动力学进行成像以了解雷特综合征小鼠模型的感觉运动功能障碍和恢复

• 批准号: MR/W004577/1
• 负责人: Ian Duguid
• 金额: $ 63.58万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FW004577%2F1
• 关键词: Imaging; macroscopic; cortical; dynamics; understand

Rett syndrome is a severe neurological disorder resulting from mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (MeCP2), a DNA binding protein that regulates brain development and function. The prevalence of Rett syndrome is estimated at 1 in 10,000 live female births where affected girls typically exhibit normal early postnatal development before experiencing a stagnation phase during the second year of life. The hallmark symptoms of Rett syndrome include loss of communication and motor skills, including purposive hand movements, breathing abnormalities and early onset seizures. Although most individuals with Rett syndrome live into adulthood their quality of life is severely impacted and they require 24-hour care. Progress in understanding the pathophysiology of Rett syndrome has been accelerated by the generation and availability of rodent models that recapitulate the developmental timeline and spectrum of patient phenotypes. Proof-of-concept pre-clinical studies demonstrate that re-introduction of the defective Mecp2 gene reverses some of the debilitating phenotypes associated with Rett syndrome giving hope to families that gene therapy could provide the 'golden bullet'. However, there are indications that re-expressing the missing MeCP2 protein recovers some body and brain functions, but not all, suggesting reversal may only be superficial. What is missing in our understanding of Rett syndrome is how loss of MeCP2 affects brainwide communication and behaviour and whether its reintroduction can drive high level brain function and phenotypic rescue. A major advance towards addressing this issue has been the recent development of optical methods which allow the simultaneous visualisation of neural activity across multiple brain regions in rodents using genetically encoded calcium sensors. We aim to use this method to establish how loss of MeCP2 affects inter-areal neural dynamics both at rest and while mice learn a novel touchscreen-based visuomotor reaching task. By imaging activity in wild type and MeCP2-mutant mice we will uncover the principal mechanism of brainwide communication breakdown that lead to deficits in high-level brain function and behaviour. Since female MeCP2-mutant mice show a mosaic expression of MeCP2 across the brain (i.e. ~40-80% of cells express MeCP2), we will use a second imaging approach that uses sheets of light to generate whole brain MeCP2 expression maps. This will allow us correlate changes in protein expression with disrupted brainwide neural dynamics and behavioural deficits. We will follow this up by asking whether reexpression of MeCP2 using viral-mediated reactivation can drive reorganisation of brainwide neural dynamics and recovery of high-level brain function and behaviour. To do this we will optimise methods for non-invasive gene reactivation in neurons across the brain and will employ optical imaging methods to map the extent of MeCP2 re-expression, reorganisation of neural activity and recovery of sensorimotor learning. Ultimately our research will provide new insights into how loss of MeCP2 leads to inter-areal communication breakdown during learning and the extent to which its reintroduction rescues high-level brain function and behaviour. This work has the potential to directly influence translational medicine through our ongoing links with the International Rett Syndrome Gene Therapy Consortium who strive to develop improved and effective treatments for Rett syndrome.

RETT综合征是一种严重的神经系统疾病，是由编码甲基CPG结合蛋白2（MECP2）的X连锁基因突变引起的，这是一种调节脑发育和功能的DNA结合蛋白。 RETT综合征的患病率估计为10,000名活着的女性出生中的1个，其中受影响的女孩通常在生命的第二年经历停滞阶段，在产后正常发育。 RETT综合征的标志性症状包括沟通和运动技能的丧失，包括有目的的手动运动，呼吸异常和早期发作。尽管大多数RETT综合征的人都生活在成年期，其生活质量受到严重影响，并且需要24小时的护理。通过概括患者表型的发育时间线和谱系的啮齿动物模型的产生和可用性，理解RETT综合征的病理生理学的进展已加速。概念验证前临床研究表明，重新引入有缺陷的MECP2基因会逆转与Rett综合征相关的一些使人衰弱的表型，从而使基因治疗可以提供“金弹”的家庭希望。但是，有迹象表明，重新表达丢失的MECP2蛋白会恢复某些身体和脑功能，但并非全部表明逆转可能仅是表面的。我们对RETT综合征的理解中缺少的是MECP2的丧失如何影响脑沟通和行为，以及其重新引入是否可以推动高水平的大脑功能和表型救援。解决此问题的主要进步是光学方法的最新发展，该方法允许使用遗传编码的钙传感器同时可视化啮齿动物中多个大脑区域的神经活动。我们的目的是使用这种方法来确定MECP2的损失如何在休息时和小鼠学习一种新型基于触摸屏的视觉运动仪到达任务时如何影响美园间的神经动力学。通过在野生型和MECP2突变小鼠中进行成像活性，我们将揭示Brainwide沟通分解的主要机制，从而导致高水平的大脑功能和行为缺陷。由于雌性MECP2突变小鼠显示MECP2在整个大脑中的镶嵌表达（即约40-80％的细胞表达MECP2），因此我们将使用第二种成像方法，该方法使用光片来生成整个脑MECP2表达图。这将使我们将蛋白质表达的变化与破坏的精神神经动力学和行为缺陷相关联。我们将通过询问使用病毒介导的重新激活对MECP2的重新表达来跟进这一点，这可以推动精心的神经动力学的重组以及高级脑功能和行为的恢复。为此，我们将优化整个大脑神经元中非侵入性基因重新激活的方法，并将采用光学成像方法来绘制MECP2重新表达的程度，对神经活动的重组和感觉运动学习的恢复。最终，我们的研究将为MECP2的损失导致学习过程中的跨沟通沟通损失以及其重新引入的程度挽救高级大脑功能和行为的程度。这项工作有可能通过我们与国际RETT综合征基因治疗联盟的持续联系直接影响转化医学，他们努力开发RETT综合征的改进和有效治疗方法。

项目成果

Movement-specific signaling is differentially distributed across motor cortex layer 5 projection neuron classes.

• DOI: 10.1016/j.celrep.2022.110801
• 发表时间: 2022-05-10
• 期刊: CELL REPORTS
• 影响因子: 8.8
• 作者: Currie, Stephen P.;Ammer, Julian J.;Premchand, Brian;Dacre, Joshua;Wu, Yufei;Eleftheriou, Constantinos;Colligan, Matt;Clarke, Thomas;Mitchell, Leah;Faisal, A. Aldo;Hennig, Matthias H.;Duguid, Ian
• 通讯作者: Duguid, Ian

Visiomode: An open-source platform for building rodent touchscreen-based behavioral assays.

• DOI: 10.1016/j.jneumeth.2022.109779
• 发表时间: 2023-02-15
• 期刊: JOURNAL OF NEUROSCIENCE METHODS
• 影响因子: 3
• 作者: Eleftheriou, Constantinos;Clarke, Thomas;Poon, V.;Zechner, Marie;Duguid, Ian
• 通讯作者: Duguid, Ian

A cranial implant for stabilizing whole-cell patch-clamp recordings in behaving rodents.

• DOI: 10.1016/j.jneumeth.2023.109827
• 发表时间: 2023-04-15
• 期刊: JOURNAL OF NEUROSCIENCE METHODS
• 影响因子: 3
• 作者: Dacre, Joshua;Rivera, Michelle Sanchez;Schiemann, Julia J.;Currie, Stephen;Ammer, Julian J.;Duguid, Ian
• 通讯作者: Duguid, Ian