Intrathecal Gene Therapy Expressing IGF-1 for Amyotrophic Lateral Sclerosis

描述（由申请人提供）：肌萎缩性侧索硬化症（ALS）是一种毁灭性的神经肌肉疾病，每年约有1 / 40000人患病。肌萎缩侧索硬化症患者表现为迅速失去肌肉控制、肌肉萎缩和因呼吸衰竭而死亡。肌萎缩侧索硬化症的病因是运动神经元对肌肉的进行性去神经支配。目前还没有治愈这种疾病的方法，唯一被批准的治疗方法对疾病进展的影响非常有限。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，由于它们的一般作用模式，可能对其他神经肌肉疾病也有作用。我们这个项目的长期目标是开发ALS的基因疗法。先前的研究调查了神经保护因子的使用。这些分子，如胰岛素样生长因子1 (IGF-1)，为运动神经元提供抗凋亡信号，并促进神经突生长。这些分子在动物实验中似乎很有前景。然而，临床试验表明，按比例调整人体剂量是一项艰巨的挑战。一种更有效的方法可能是使用基因疗法，让患者自己的细胞产生治疗因子。包括我们自己的研究在内的几项研究表明，这种方法有其优点。然而，这些研究使用的技术并没有在更大的动物模型中得到很好的推广。脊髓实质内注射只导致局部转基因表达，因此需要在人类中进行不合理的大量注射。在肌萎缩侧索硬化症啮齿类动物模型中，注射到肌肉中的载体的运动神经元逆行转运也有效，但由于需要注射的肌肉量，可能再次具有有限的临床适用性。在这项提议中，我们将研究鞘内给予表达IGF-1的基因治疗在SOD1-G93A肌萎缩性侧索硬化症大鼠模型中的疗效。在Specific Aim 1中，我们展示了我们的基因治疗可以促进运动神经元的存活并保护神经肌肉连接的完整性。此外，我们将证明这种疗法减弱星形胶质细胞和小胶质细胞的激活，这有助于破坏运动神经元。此外，我们将研究运动神经元对IGF-1水平升高产生耐受性的可能性，这一现象可能会限制这种治疗的长期有效性。在具体目标2中，我们将展示在目标1中发现的改善转化为运动功能的改善和寿命的延长。SOD1大鼠将通过握力、旋转杆和开阔场地测试来评估运动功能的几个方面。此外，将测量寿命、发病年龄和疾病进展速度以显示疗效。这项研究将提供必要的原理证明数据，以支持该方法的未来临床试验。

DESCRIPTION (provided by applicant): 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 th 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.