Rad and amyotrophic lateral sclerosis (ALS)

肌萎缩性侧索硬化症（ALS）是一种成人发病的神经退行性疾病，其通常是致命的， 三到五年后出现症状。这种疾病的特征是进行性的丧失， 运动神经系统和随意肌功能，对中枢或感觉神经功能无明显影响。 由于这个原因，受折磨的人在屈服于疾病之前，实际上成为了他们自己身体的囚犯。 呼吸麻痹到目前为止，还没有真正有效的方法来减缓或逆转ALS的进展。 虽然运动神经元死亡是ALS最公认的特征，但ALS的分子事件 并不局限于神经系统对ALS病理学更准确的描述是， 因为失去了运动神经在这方面，运动神经元之间脆弱的连接的保真度和 骨骼肌（神经肌肉接头）不仅依赖于神经元的输入， 效应器肌肉因此，这项研究的长期目标是了解骨骼肌是如何 功能障碍导致神经肌肉接头的不稳定和运动神经元的死亡， 多种形式的ALS。在该提案的规定期限内，单体G蛋白Rad（Ras-1）的作用 与糖尿病相关）在ALS发病机制中的作用。拉德是特别感兴趣的 因为：1）Rad表达在散发性ALS的肌肉中的症状呈现之前增强 2）Rad是一种有效的ALS抑制剂， 骨骼肌L型钙通道（CaV1.1），和3）慢性上调的Rad导致显着的肌肉 萎缩初步数据还表明，CaV 1.1-L型Ca ~（2+）通道的两种生理功能， 兴奋-收缩（EC）偶联的电压传感器-在小鼠肌肉中全面进行性受损 在表达SOD 1G 93 A的小鼠中以及在其中SOD 1G 93 A表达已被限制于骨骼肌的小鼠中。要求1 将确定肌肉中Rad的慢性上调是否会导致NMJ不稳定，以及随后的 运动神经元死亡在这些实验中，AAV 1介导的肌肉特异性Rad过表达的影响 对运动神经元活力的影响将使用免疫组织化学和 电生理学方法。在目标2中，将创建一个Rad null-SOD 1G 93 A鼠标线，以显示 Rad直接参与促进肌肉萎缩、NMJ不稳定和运动神经元死亡。恶心， 运动，组织学，超微结构和电生理技术，然后将被用来确定 Rad的基因消融是否可以限制SOD 1G 93 A对肌肉完整性的有害影响， 运动神经元活力使用qRT-PCR、免疫印迹和膜片钳电生理学，Aim 3将测试 Rad表达增强和CaV1.1功能抑制是否是多种形式ALS的共同点。

Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder that is typically fatal within three to five years of the appearance of symptoms. The disease is characterized by the progressive loss of the motor nervous system and voluntary muscle function without great effect on central or sensory neural function. For this reason, afflicted individuals effectively become prisoners within their own bodies before succumbing to respiratory paralysis. To date, there is no truly effective means to slow or reverse the progression of ALS. While motoneuron death is the most recognized characteristic of ALS, the molecular events that underlie ALS are not restricted to the nervous system. A more accurate description of ALS pathology is that paralysis occurs as a result of motor unit loss. In this regard, the fidelity of the fragile connections between motoneurons and skeletal muscle (neuromuscular junctions) is dependent not only on neuronal input but also on the integrity of the effector muscle. Thus, the long-term goal of this research is to understand how skeletal muscle dysfunction contributes to the destabilization of neuromuscular junctions and motoneuron death in multiple forms of ALS. In the defined duration of this proposal, a role for the monomeric G protein Rad (Ras- related Associated with Diabetes) in ALS pathogenesis will be investigated. Rad is of particular interest because: 1) Rad expression is enhanced just prior to presentation of symptoms in muscle of sporadic ALS patients and two established familial ALS mouse models (SOD1G93A and SOD1G86R), 2) Rad is a potent inhibitor of skeletal muscle L-type Ca2+ channels (CaV1.1), and 3) chronic upregulation of Rad causes marked muscle atrophy. Preliminary data also indicate that the two physiological functions of CaV1.1 - L-type Ca2+ channel and voltage-sensor for excitation-contraction (EC) coupling - are progressively impaired in muscle of mice globally expressing SOD1G93A and in mice in which SOD1G93A expression has been restricted to skeletal muscle. Aim 1 will determine whether chronic upregulation of Rad in muscle can cause NMJ destabilization and subsequent motoneuron death. In these experiments, the impact of AAV1-mediated, muscle-specific Rad overexpression on motoneuron viability will be assessed longitudinally using a combination of immunohistological and electrophysiological methods. In Aim 2, a Rad null-SOD1G93A mouse line will be created in order to reveal the direct involvement of Rad in promoting muscle atrophy, NMJ destabilization and motoneuron death. Gross, locomotor, histological, ultrastructural and electrophysiological techniques will then be employed to determine whether genetic ablation of Rad can limit the deleterious effects of SOD1G93A on muscle integrity and motoneuron viability. Using qRT-PCR, immunoblotting and patch-clamp electrophysiology, Aim 3 will test whether enhanced Rad expression and depression of CaV1.1 function are common to multiple forms of ALS.