Mechanisms of neuronal network dysfunction in juvenile neuronal ceroid lipofuscinosis

项目摘要 大多数代谢性疾病，包括三分之二的溶酶体贮积症（LSD）都会影响大脑。对许多人来说， 包括青少年神经元蜡样脂褐质沉积症（JNCL），尚不清楚生化缺陷如何诱导 中枢神经系统功能障碍研究集中在细胞水平的病理学，很少调查 代谢缺陷是如何破坏功能性神经回路的最终，大脑网络的破坏导致 这些症状，如癫痫发作和神经认知退化，对患者来说是毁灭性的。 JNCL由CLN 3中的双等位基因突变产生。CLN 3蛋白的丢失如何破坏神经功能， 不清楚在初步工作中，我已经证明JNCL小鼠，像人类患者一样， 这表明小鼠是用于回路水平研究的合适模型。尸检时，JNCL 大脑表现出神经变性和溶酶体蓄积;海马尤其是 脆弱在我对JNCL小鼠海马的初步电压敏感染料成像（VSDI）研究中， 发现了兴奋性的渐进变化此外，最近对晚期JNCL的研究表明， 小鼠海马体的功能障碍。然而，在晚期疾病的研究中， 这些变化是由于CLN 3蛋白的原发性丢失或继发于广泛的神经病理学。 基因和/或酶替代疗法正在开发用于许多LSD。虽然这是令人兴奋的，移动到 在我们知道替换是否能治愈病人之前进行基因治疗是有问题的。在哪里及什么时候 拯救蛋白的表达尚不清楚。一个尚未解决的主要问题是，如果纠正生化缺陷， 潜在的代谢疾病将拯救神经网络的功能并改善症状。 我的中心假设是，在JNCL中，海马回路病理学是由诱导的突触功能障碍引起的， CLN 3蛋白的丢失。由于发展异常的网络动态，一个脆弱的窗口 可能存在，超过该限度，单细胞生物化学的校正将不能校正功能缺陷。我会评价 这是通过：1）在两个JNCL模型中使用VSDI定义电路级病理; 2）探索突触和 细胞变化驱动网络变化，以及3）评估是否在不同阶段拯救CLN 3表达 疾病可以挽救电路和突触动力学。这项工作对今后的研究具有重要意义。 CLN 3蛋白的基础科学和JNCL的新疗法。 作为一名医学博士/博士，我热衷于将基础科学发现转化为患者的新疗法 神经代谢紊乱我的导师埃里克·马什博士，一位神经遗传学家， 电生理学家，以及Beverly Davidson博士，一位溶酶体储存病专家， 为了这个目标。在他们的指导下，我将利用这5年的经验来学习应用我的电生理技能 大脑的研究，并准备作为一个独立的R 01资助的翻译研究人员的职业生涯。

PROJECT SUMMARY Most metabolic diseases, including two-thirds of lysosomal storage disorders (LSD) affect the brain. For many, including Juvenile Neuronal Ceroid Lipofuscinosis (JNCL), it is not known how the biochemical defect induces central nervous system dysfunction. Studies have focused on cellular-level pathology, with few investigations of how metabolic defects disrupt functional neuronal circuits. Ultimately, disruption of brain networks leads to the symptoms, such as seizures and neurocognitive regression, that are devastating to patients. JNCL results from biallelic mutations in CLN3. How loss of CLN3 protein disrupts neurologic function is unclear. In preliminary work, I have demonstrated that JNCL mice, like human patients, have abnormal electroencephalograms, suggesting mice are a suitable model for circuit-level studies. On autopsy, JNCL brains show neurodegeneration and lysosomal storage accumulation; the hippocampus is especially vulnerable. In my preliminary voltage-sensitive dye imaging (VSDI) studies of the JNCL mouse hippocampus, I have found progressive changes in excitability. Also, recent studies of late-stage JNCL show synaptic dysfunction in the mouse hippocampus. However, in studies of late-stage disease it is impossible to parse which changes are due to the primary loss of CLN3 protein or secondary to widespread neuropathology. Gene and/or enzyme replacement therapy is being developed for many LSDs. While this is exciting, moving to gene-based treatment before we know if replacement will fix the patients is problematic. Where and when to rescue protein expression is unclear. A major unanswered question is if correction of the biochemical defect underlying a metabolic disease will rescue the function of neuronal networks and improve symptoms. My central hypothesis is that in JNCL, hippocampal circuit pathology arises from synaptic dysfunction induced by loss of CLN3 protein. Because of the development of abnormal network dynamics, a vulnerable window may exist beyond which correction of single cell biochemistry will not correct functional defects. I will evaluate this by: 1) defining circuit level pathology using VSDI in two JNCL models; 2) exploring the synaptic and cellular changes driving network changes, and 3) assessing if rescue of CLN3 expression at different stages of disease can rescue circuit and synaptic dynamics. This work has important implications for future studies of the basic science of the CLN3 protein and novel therapies for JNCL. As an MD/PhD, I am passionate about translating basic science discoveries into new therapies for my patients with neurometabolic disorders. My mentors Dr. Eric Marsh, a physician-scientist neurogeneticist and electrophysiologist, and Dr. Beverly Davidson, a lysosomal storage disease expert, have devoted their careers to this goal. Under their guidance, I will use this 5-year experience to learn to apply my electrophysiology skills to studies of the brain and to prepare for a career as an independent R01-funded translational researcher.