Role of Potent Trophic Factors on Glia and Motor Neurons in ALS

描述（由申请人提供）：肌萎缩侧索硬化症（ALS）是一种破坏性运动神经元疾病，可导致肌肉麻痹和最终呼吸衰竭和死亡。ALS的根本原因仍然未知，无法治愈。许多报告，包括我们实验室的工作已经证明了神经营养因子在家族性ALS（fALS）啮齿动物模型中具有高度治疗性的潜力。事实上，在ALS啮齿动物模型中疾病发作时递送的胰岛素样生长因子-1（IGF-1）、胶质源性神经营养因子（GDNF）和血管内皮生长因子（VEGF）已经证明在延迟疾病进展方面具有深远的作用。最近的研究令人惊讶地表明，表达超氧化物歧化酶突变的星形胶质细胞和小胶质细胞可以加剧运动神经元死亡，支持ALS是一种非细胞自主性疾病的早期研究。具体来说，神经胶质细胞已被证明会产生异常活动，分泌导致运动神经元死亡的毒性信号。基于这些结果，旨在中和神经胶质细胞毒性的疗法将对ALS患者非常有益。在基因筛查确定新的ALS诱导基因之前，应该开发可能延长ALS患者生命的疗法。神经营养因子延长存活和运动功能的机制仍然是难以捉摸的。我们实验室最近的初步工作表明，IGF-1和VEGF都可以抑制突变胶质细胞介导的毒性。在这个建议中，我们将研究IGF-1，VEGF和GDNF抑制异常胶质细胞活性和延迟运动神经元死亡的相对效率。具体而言，这些因素将利用我们实验室最近开发的宝贵的ALS体外模型进行测试。我们还将在体内AAV（腺相关病毒）基因递送模式中测试这些因素，该模式有效地靶向脊髓的所有区域。我们将分析这些营养因子介导其对星形胶质细胞的作用的机制，最后，我们将使用我们在AAV载体基因递送至CNS方面的专业知识在家族性fALS小鼠中测试这些因子的最佳组合。本提案的具体目标是：具体目标1）。确定在体外fALS模型中使用强效神经营养因子的神经保护和神经胶质细胞毒性降低的效率。具体目标2.）确定IGF-1、VEGF和GDNF是否联合作用以改变异常ALS胶质活性并在体外fALS模型中提供额外的神经保护。具体目标3.）确定联合神经营养因子治疗是否对fALS小鼠模型有益。肌萎缩性侧索硬化症（ALS）是一种破坏性运动神经元疾病，可导致肌肉瘫痪，最终导致呼吸衰竭和死亡。ALS的根本原因仍然未知，无法治愈。我们已经显示了神经营养因子在家族性ALS的啮齿动物模型中具有高度治疗性的潜力，包括IGF-1、VEGF和GDNF。我们的建议侧重于评估最佳的营养因子单独或组合，以延缓运动神经元变性。我们已经开发了一种基于体外的ALS模型，该模型利用针对运动神经元的干细胞和含有星形胶质细胞的ALS，其概括了该疾病。随后，我们将在这种毁灭性疾病的啮齿动物模型中使用基因递送来测试这些因素的最佳组合，以确定这种使人衰弱的疾病的最佳疗法。

DESCRIPTION (provided by applicant): Amyotrophic lateral sclerosis (ALS) is a devastating motor neuron disease, which results in muscle paralysis and ultimate respiratory failure and death. The underlying cause for ALS remains unknown with no cure. Numerous reports, including work from our laboratory have demonstrated the potential for neurotrophic factors to be highly therapeutic in rodent models of familial ALS (fALS). Indeed, Insulin-like growth factor-1 (IGF-1), glial derived neurotrophic factor (GDNF), and vascular endothelial growth factor (VEGF) delivered at disease onset in ALS rodent models have demonstrated profound effects in delaying disease progression. Recent studies have surprisingly demonstrated that astrocytes and microglia expressing a mutation in the enzyme superoxide dismutase can exacerbate motor neuron death, supporting earlier studies that ALS is a non-cell autonomous disease. Specifically, glial cells have been shown to develop aberrant activity, secreting toxic signals that lead to motor neuron demise. Based on these results, therapies designed to neutralize glial cell toxicity would be highly beneficial to ALS patients. Until genetic screening identifies new ALS inducing genes, therapies that could potentially prolong the lives of ALS patients should be developed. The mechanism by which neurotrophic factors prolong survival and motor function has remained elusive. Recent preliminary work by our laboratory has demonstrated that both IGF-1 and VEGF can act to suppress the mutant glial cell mediated toxicity. In this proposal, we will investigate the relative efficiency of IGF-1, VEGF and GDNF to suppress aberrant glial activity and delay motor neuron death. Specifically, these factors will be tested utilizing an invaluable in vitro model for ALS that was recently developed in our laboratory. We will also test these factors in an in vivo AAV (Adeno-Associated Virus) gene delivery paradigm that efficiently targets all regions of the spinal cord. We will analyze the mechanism by which these trophic factors mediate their effects on astrocytes and finally, we will test an optimal combination of these factors in familial fALS mice using our expertise in AAV vector gene delivery to the CNS. The specific aims of this proposal are: Specific Aim 1.) To determine the efficiency of neuroprotection and reduction of glial cell toxicity using potent neurotrophins in an in vitro based model of fALS. Specific Aim 2.) To determine whether IGF-1, VEGF, and GDNF act in combination to alter aberrant ALS glial activity and provide additive neuroprotection in an in vitro based model of fALS. Specific Aim 3.) To determine whether a combinatorial neurotrophic factor therapy is beneficial in a mouse model of fALS. PUBLIC HEALTH RELEVANCE Amyotrophic lateral sclerosis (ALS) is a devastating motor neuron disease, which results in muscle paralysis and ultimate respiratory failure and death. The underlying cause for ALS remains unknown with no cure. We have shown the potential for neurotrophic factors to be highly therapeutic in rodent models of familial ALS including IGF-1, VEGF, and GDNF. Our proposal focuses on evaluating optimal trophic factors individually or in combination to delay motor neuron degeneration. We have developed an in vitro based model of ALS that utilizes stem cells directed to motor neurons and ALS containing astrocytes, which recapitulates the disease. We will subsequently test the optimal combination of these factors using gene delivery in a rodent model of this devastating disease in order to define an optimal therapy for this debilitating disorder.