Intrathecal Gene Therapy Expressing IGF-1 for Amyotrophic Lateral Sclerosis

肌萎缩性侧索硬化症（ALS）是一种破坏性的神经肌肉疾病，发病率约为1/40，000 每年.患有ALS的个体表现出肌肉控制的快速丧失、肌肉萎缩和由于肌肉萎缩而死亡。 呼吸衰竭ALS的原因是运动神经元对肌肉的进行性去神经支配。有 目前还没有治愈这种疾病的方法，唯一批准的治疗方法对这种疾病的影响非常有限 进展显然，迫切需要更有效的治疗方法。一种可能的途径是 使用神经保护因子，由于其一般作用模式，可能在其他神经肌肉 紊乱也是。我们这个项目的长期目标是开发ALS的基因疗法。以前的研究 研究了神经保护因子的使用。这些分子，如胰岛素样生长因子1 胰岛素样生长因子-1（IGF-1）为运动神经元提供抗凋亡信号以及促进神经突生长。这些 分子在动物研究中似乎很有前途。然而，临床试验表明， 人类面临着巨大的挑战。一个更有效的方法可能是使用基因治疗， 患者自身的细胞来产生治疗因子。包括我们自己在内的几项研究都表明了这一点 方法有优点。然而，这些研究使用的技术在大型动物中没有很好地扩大规模。 模型实质内注射到脊髓中仅导致局部的转基因表达， 需要不合理的大量注射。运动神经元的逆行转运 注射到肌肉中的载体在ALS的啮齿动物模型中也是有效的，但可能再次受到限制。 由于需要注射的肌肉质量，因此不具有临床适用性。在本提案中，我们将调查 在ALS的SOD 1-G93 A大鼠模型中鞘内施用表达IGF-1的基因疗法的功效。在 具体目标1，我们表明，我们的基因治疗可以促进运动神经元的存活和保护的完整性， 神经肌肉接头此外，我们将表明，这种疗法减弱了星形胶质细胞的激活， 有助于破坏运动神经元的小胶质细胞。此外，我们将调查 运动神经元可能对IGF-1水平升高产生耐受性，这一现象可能限制 这种疗法的长期效果。在具体目标2中，我们将展示目标中的改进 1转化为改善运动功能和延长寿命。将使用夹持评价SOD 1大鼠 力量、旋转杆和开放场地测试，以评估运动功能的几个方面。此外，寿命、年龄 在疾病发作时，将测量疾病进展的速率以显示功效。本研究将 提供必要的原理验证数据，以支持这种方法的未来临床试验。

Amyotrophic lateral sclerosis (ALS) is a devastating neuromuscular disorder striking about 1 person in 40,000 each year. Individuals with ALS exhibit rapid loss of muscle control, muscle atrophy, and death due to respiratory failure. The cause of ALS is the progressive denervation of muscle by motor neurons. There is currently no cure for this disease, and the only approved therapy has a very modest effect on the disease progression. Clearly, there is a pressing need for more effective therapies. One possible route would be to use neuroprotective factors which, due to their general mode of action, may have utility in other neuromuscular disorders as well. Our long-term objective for this project is to develop gene therapy for ALS. Previous studies have investigated the use of neuroprotective factors. These molecules, such as insulin-like growth factor 1 (IGF-1) provide anti-apoptotic signals for motor neurons as well as promoting neurite outgrowth. These molecules seemed promising in animal studies. However, clinical trials demonstrated that scaling the dose to humans poses daunting challenges. A more effective approach might be to use gene therapy to allow the patients' own cells to produce the therapeutic factor. Several studies, including our own, have shown this approach has merit. However, these studies used techniques that have not scaled up well in larger animal models. Intraparenchymal injection into the spinal cord results in only localized transgene expression and thus would require an unreasonably large number of injections in humans. Retrograde transport in motor neurons of vector injected into muscle was also effective in a rodent model of ALS, but again would likely have limited clinical applicability due to the muscle mass that would need to be injected. In this proposal we will investigate efficacy of intrathecally administered gene therapy expressing IGF-1 in the SOD1-G93A rat model of ALS. In Specific Aim 1, we show that our gene therapy can promote motor neuron survival and protect the integrity of neuromuscular junctions. In addition we will show that this therapy attenuates the activation of astrocytes and microglia that helps contribute to the destruction of motor neurons. Furthermore, we will investigate the possibility that motor neurons can develop tolerance to elevated levels of IGF-1, a phenomenon that could limit the effectiveness of this therapy long-term. In Specific Aim 2, we will show that the improvements found in Aim 1 translate into improved motor function and increased life span. SOD1 rats will be evaluated using the grip strength, rotarod, and open field tests to evaluate several aspects of motor function. In addition, life span, age at disease onset, and the rate of disease progression will be measured to show efficacy. This study will provide the proof-of-principle data necessary to support future clinical trials of this approach.