Control of Breathing & Glycogen Storage Disease

呼吸的控制

• 批准号: 7356059
• 负责人: DAVID D FULLER
• 金额: $ 30.51万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-02-15 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7356059
• 关键词: Acids; Address; Adolescent; Adult; Adult Glycogen Storage Disease Type II; Age of Onset; Animal Model; Attenuated; Autopsy; Behavioral; Biochemical; Blood - brain barrier anatomy; Breathing; Case Study; Cell Nucleus; Cervical; Clinical; Collaborations; Data; Disease; Environmental air flow; Enzymes; Exhibits; Failure; Foundations; Future; Gene Delivery; Genes; Genetically Engineered Mouse; Glycogen; Glycogen Storage Disease; Glycogen storage disease type II; Impairment; Infant; Infantile Glycogen Storage Disease Type II; Injection of therapeutic agent; Investigation; Knockout Mice; Laboratories; Localized; Mediating; Metabolic; Methods; Modeling; Molecular; Motor; Motor Neurons; Motor output; Mus; Muscle; Neuraxis; Neuroanatomy; Output; Pathology; Phenotype; Preclinical Testing; Rate; Recombinant adeno-associated virus (rAAV); Relative (related person); Replacement Therapy; Research; Research Personnel; Respiratory Diaphragm; Respiratory Failure; Respiratory Insufficiency; Respiratory Muscles; Respiratory physiology; Secondary to; Skeletal Muscle; Spinal; Spinal Injections; Structure of phrenic nerve; Technology; Testing; Treatment Efficacy; Viral; Wild Type Mouse; awake; base; enzyme activity; enzyme replacement therapy; experience; extracellular; gene correction; gene replacement; gene therapy; glucosidase; motor deficit; neuromechanism; neurophysiology; novel; programs; relating to nervous system; research study; respiratory; success; tool

DESCRIPTION (provided by applicant): Glycogen storage disease type II (GSDII) results from deficiency of acid a-glucosidase (GAA), a lysosomal enzyme that degrades glycogen. GSDII causes cardiorespiratory failure in infants, and progressive respiratory failure in juveniles and adults. Although respiratory failure has been attributed to muscle pathology, autopsy case reports show cervical spinal glycogen accumulation and suggest motoneuron pathology. We have observed that efferent phrenic discharge, mean inspiratory airflow, and the ratio of minute ventilation to metabolic rate (VE/VCO2) are blunted in a murine GSDII model, the GAA-/- "knockout" mouse. In addition, a selective knockout mouse with normal skeletal muscle contractility and GAA expression, but no GAA in the central nervous system (CNS), also exhibits marked reductions in phrenic output and ventilation. Accordingly, CNS GAA deficiency is associated with impaired respiratory motor output, and respiratory insufficiency in GSDII may reflect both a neural and a muscular pathology. A neural mechanism is also implicated by preliminary data showing extensive cervical spinal glycogen accumulation in GAA-/- mice, particularly within retrogradely identified phrenic motoneurons. Determining the mechanisms underlying respiratory insufficiency is important because i.v. enzyme replacement (the current clinical GSDII therapy) does not target the CNS as GAA cannot cross the blood brain barrier. A promising method for targeting both muscle and the CNS is recombinant adeno-associated virus (rAAV) gene therapy. Our preliminary data indicate that rAAV effectively transfects phrenic motoneurons, and can be delivered by intraspinal or intrathoracic injection. Further, ventilation is significantly enhanced in GAA-/- mice one month following intrathoracic injection of rAAV packaged with the GAA gene (rAAV-GAA therapy). These experiments represent a unique collaboration between laboratories specializing in respiratory physiology (Fuller), gene therapy (Byrne), and neuroanatomy (Reier). We propose to test three hypotheses: 1) neural drive to the diaphragm and ventilation are attenuated in both the selective and full GAA-/- knockout mice; 2) respiratory deficits in these mice occur in parallel with glycogen accumulation in phrenic motoneurons, and 3) intraspinal and intrathoracic rAAV-GAA delivery can ameliorate spinal glycogen accumulation and enhance respiratory motor output in the selective and GAA-/- knockout mice, respectively.

描述（由申请人提供）：II型糖原贮积病（GSDII）是由于酸性α-葡萄糖苷酶（GAA）缺乏所致，GAA是一种降解糖原的溶酶体酶。 GSDII 会导致婴儿心肺衰竭，以及青少年和成人进行性呼吸衰竭。尽管呼吸衰竭被归因于肌肉病理学，但尸检病例报告显示颈部脊髓糖原积聚并提示运动神经元病理学。我们观察到，在小鼠 GSDII 模型（GAA-/-“基因敲除”小鼠）中，传出膈放电、平均吸气气流以及每分钟通气量与代谢率 (VE/VCO2) 的比率均减弱。此外，具有正常骨骼肌收缩力和 GAA 表达但中枢神经系统 (CNS) 中没有 GAA 的选择性基因敲除小鼠也表现出膈输出和通气显着减少。因此，CNS GAA 缺乏与呼吸运动输出受损有关，GSDII 中的呼吸功能不全可能反映了神经和肌肉病理学。初步数据显示 GAA-/- 小鼠颈椎糖原大量积累，特别是在逆行识别的膈运动神经元内，也暗示了神经机制。确定呼吸功能不全的机制很重要，因为静脉注射。酶替代（目前临床上的 GSDII 疗法）并不针对 CNS，因为 GAA 无法穿过血脑屏障。重组腺相关病毒（rAAV）基因治疗是一种有前途的针对肌肉和中枢神经系统的方法。我们的初步数据表明，rAAV 有效转染膈运动神经元，并且可以通过脊柱内或胸腔内注射进行递送。此外，在胸腔内注射包装有GAA基因的rAAV（rAAV-GAA疗法）1个月后，GAA-/-小鼠的通气显着增强。这些实验代表了专门从事呼吸生理学（Fuller）、基因治疗（Byrne）和神经解剖学（Reier）实验室之间的独特合作。我们建议测试三个假设：1）选择性和完全 GAA-/- 基因敲除小鼠中膈肌和通气的神经驱动均减弱； 2) 这些小鼠的呼吸缺陷与膈运动神经元中的糖原积累同时发生，3) 脊柱内和胸腔内 rAAV-GAA 递送可以分别改善选择性小鼠和 GAA-/- 敲除小鼠的脊髓糖原积累并增强呼吸运动输出。