Physiology of mitochondrial dysfunction in genetic models of Parkinson's disease

帕金森病遗传模型中线粒体功能障碍的生理学

基本信息

批准号：
7733846
负责人：
Carl R. Lupica
金额：
$ 36.53万
依托单位：
NATIONAL INSTITUTE ON DRUG ABUSE
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/7733846
关键词：
Action Potentials Acute Affect Animals Back Breeding Cell Respiration Cells Code Corpus striatum structure Dependovirus Development Disease Progression Dopamine Energy Metabolism Enzymes Functional disorder Gene Expression Genes Genetic Models Genetic Transcription Human Impairment Institutes Levodopa Mediating Membrane Membrane Potentials Midbrain structure Mitochondria Mitochondrial DNA Modeling Mus Mutation Nerve Degeneration Neurodegenerative Disorders Neurons Neurotoxins Oxidative Phosphorylation Parkinson Disease Parkinsonian Disorders Pharmacological Treatment Phenotype Physiological Physiology Pilot Projects Property Quality of life Research Research Design Substantia nigra structure Sweden Testing Therapeutic Therapeutic Intervention Thinking Time Viral Week Work density dopamine transporter dopaminergic neuron gene therapy glial cell-line derived neurotrophic factor improved interest mitochondrial dysfunction mitopark mouse mtTF1 transcription factor nervous system disorder neurotrophic factor novel therapeutics prevent promoter

项目摘要

We have begun to examine the neurodegeneration that occurs in a genetically modified mouse that was developed by our collaborators at the Karolinska Institute in Sweden. We have now established a successful breeding colony of these mice at our institute, and we have made them available to our local collaborators. These mice possess a mutation in the mitochondrial gene known as mitochondrial transcription factor A (tFam). This gene regulates mitochondrial DNA transcription in all cells, and is necessary for continued oxidative phosphorylation. However, by targeting this mutation to dopamine neurons using the promoter that drives dopamine transporter expression, only these neurons are affected by the mutation. Our present work shows that the DA neurons degenerate slowly over a 30 week period, and that these "MitoPark" mice display many hallmarks of Parkinsons disease in humans. This includes sensitivity to pharmacological treatments, such as L-Dopa therapy, and the loss of this therapeutic benefit as the neurodegeneration progresses. Our studies have also shown that expression of glial cell line-derived neurotrophic factor (GDNF) through adeno-associated virus (AAV) can spare these dopamine neurons, and protect against either neurotoxin or genetically induced parkinsonism in mice. In addition, in pilot studies conducted with the dopamine neurotoxin MPTP, we have found that the loss of dopamine causes profound changes in the physiological properties of the striatum that were also prevented by AAV-mediated gene expression of GDNF. We will now begin to test this form of gene therapy in the tFam genetic model of Parkinsons disease, and attempt to reverse the neurodegeneration at various time points during the disease progression. Our most recent work with the MitoPark mice reveals an interesting change in DA neuron physiology at a time during development at which the animals are behaviorally asymptomatic. We find a dramatic reduction in the presence of a membrane current known as "Ih" in the DA neurons located in the substantia nigra, This current is normally responsible for re-setting the neuronal membrane potential back near action potential threshold following a large inhibition. Therefore it is thought that Ih is responsible for maintaining normal pacemaking function in DA neurons. We are currently assessing the relevance of this change in Ih density in MitoPark mice, and theorize that a loss of Ih may represent one of the early consequences of mitochondrial impairment in DA neurons degenerating in Parkinson's disease

我们已经开始研究由我们在瑞典Karolinska研究所的合作者开发的转基因小鼠中发生的神经变性。现在，我们已经在我们的研究所建立了这些小鼠的成功繁殖殖民地，我们已将其提供给当地的合作者。这些小鼠在称为线粒体转录因子A（TFAM）的线粒体基因中具有突变。该基因调节所有细胞中的线粒体DNA转录，对于持续氧化磷酸化是必不可少的。但是，通过使用驱动多巴胺转运蛋白表达的启动子将该突变靶向多巴胺神经元，只有这些神经元受到突变的影响。我们目前的工作表明，DA神经元在30周内缓慢退化，并且这些“ Mitopark”小鼠在人类中表现出许多帕金森氏病的标志。这包括对药理疗法的敏感性，例如L-DOPA疗法，以及随着神经变性的发展，这种治疗益处的丧失。我们的研究还表明，通过与腺相关病毒（AAV）（AAV）的神经胶质细胞系衍生的神经营养因子（GDNF）的表达可以免除这些多巴胺神经元，并预防小鼠中神经毒素或遗传诱导的帕金森主义。此外，在用多巴胺神经毒素MPTP进行的试点研究中，我们发现多巴胺的丧失会导致纹状体的生理特性发生深刻的变化，而GDNF的AAV介导的基因表达也阻止了纹状体的生理特性。现在，我们将开始在帕金森氏病的TFAM遗传模型中测试这种形式的基因治疗，并试图在疾病进展过程中的各个时间点扭转神经退行性。我们与Mitopark小鼠的最新工作揭示了在发育过程中动物无症状的发育过程中，DA神经元生理的有趣变化。我们发现，在尼格拉底的DA神经元中存在称为“ IH”的膜电流的存在急剧减少，该电流通常负责重新设置大型抑制后的神经元膜电位接近动作电位阈值。因此，人们认为IH负责维持DA神经元中的正常起搏功能。我们目前正在评估Mitopark小鼠IH密度变化的相关性，并认为IH的损失可能代表DA神经元在帕金森氏病中脱离DA神经元的早期后果之一