Selective degeneration of a physiological subtype of spinal motor neuron in mice with SOD1-linked ALS
Selective degeneration of a physiological subtype of spinal motor neuron in mice with SOD1-linked ALS
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DOI：
10.1073/pnas.1419497111
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发表时间：
2014-11-25
影响因子：
11.1
通讯作者：
McCormick, David A.
中科院分区：
文献类型：
--
作者：
Hadzipasic, Muhamed;Tahvildari, Babak;McCormick, David A.
肌萎缩侧索硬化症（ALS; Lou Gehrig病）影响脑和脊髓中的运动神经元（MN）。了解这种情况的病理生理学似乎是至关重要的治疗设计，但很少有电生理学研究积极退化的动物模型已被报道。在这里，我们报告了一种新的制备急性切片从成年小鼠脊髓，允许可视化的全细胞膜片钳记录荧光腰椎MN细胞体从ChAT-eGFP或超氧化物歧化酶1-黄色荧光蛋白（SOD 1 YFP）转基因动物长达6个月的年龄。我们研究了成年ChAT-eGFP小鼠MN的11种内在电生理特性，并根据这些参数将其分为四种亚型。亚型主要与瞬时（初始）和稳态放电率相关。我们使用逆行追踪使用荧光染料注射到快速或缓慢收缩下肢肌肉与切片记录从荧光标记的腰椎MN细胞体，以建立快速和缓慢发射MN连接到快速和缓慢收缩肌肉，分别。在ALS的G85 R SOD 1 YFP转基因小鼠模型中，其在5-6个月时瘫痪，其中MN细胞体是荧光的，使得能够从脊髓组织切片进行相同类型的记录，我们观察到所有四种MN亚型在2个月龄时存在。在4个月时，此时已经发生了大量的神经元SOD 1 YFP聚集和细胞损失，并且症状已经发展，其中一种使快缩肌失活的快速放电亚型丢失。这些结果开始描述了ALS的病理生理事件的顺序。
Amyotrophic lateral sclerosis (ALS; Lou Gehrig's disease) affects motor neurons (MNs) in the brain and spinal cord. Understanding the pathophysiology of this condition seems crucial for therapeutic design, yet few electrophysiological studies in actively degenerating animal models have been reported. Here, we report a novel preparation of acute slices from adult mouse spinal cord, allowing visualized whole cell patch-clamp recordings of fluorescent lumbar MN cell bodies from ChAT-eGFP or superoxide dismutase 1-yellow fluorescent protein (SOD1YFP) transgenic animals up to 6 mo of age. We examined 11 intrinsic electrophysiologic properties of adult ChAT-eGFP mouse MNs and classified them into four subtypes based on these parameters. The subtypes could be principally correlated with instantaneous (initial) and steady-state firing rates. We used retrograde tracing using fluorescent dye injected into fast or slow twitch lower extremity muscle with slice recordings from the fluorescent-labeled lumbar MN cell bodies to establish that fast and slow firing MNs are connected with fast and slow twitch muscle, respectively. In a G85R SOD1YFP transgenic mouse model of ALS, which becomes paralyzed by 5-6 mo, where MN cell bodies are fluorescent, enabling the same type of recording from spinal cord tissue slices, we observed that all four MN subtypes were present at 2 mo of age. At 4 mo, by which time substantial neuronal SOD1YFP aggregation and cell loss has occurred and symptoms have developed, one of the fast firing subtypes that innvervates fast twitch muscle was lost. These results begin to describe an order of the pathophysiologic events in ALS.