Twenty per cent of familial amyotrophic lateral sclerosis (fALS) cases are caused by mutations in the gene encoding human cytosolic Cu/Zn superoxide dismutase (hSOD1). Efficient translation of the therapeutic potential of interfering RNA (RNAi) for the treatment of SOD1-ALS patients requires the development of vectors that are free of significant off-target effects and with reliable biomarkers to discern sufficient target engagement and correct dosing. Using adeno-associated virus serotype 9 to deliver RNAi against hSOD1 in the SOD1^G93A mouse model, we found that intrathecal injection of the therapeutic vector via the cisterna magna delayed onset of disease, decreased motor neuron death at end stage by up to 88% and prolonged the median survival of SOD1^G93A mice by up to 42%. To our knowledge this is the first report to demonstrate no significant off-target effects linked to hSOD1 silencing, providing further confidence in the specificity of this approach. We also report the measurement of cerebrospinal fluid (CSF) hSOD1 protein levels as a biomarker of effective dosing and efficacy of hSOD1 knockdown. Together, these data provide further confidence in the safety of the clinical therapeutic vector. The CSF biomarker will be a useful measure of biological activity for translation into human clinical trials.

家族性肌萎缩性侧索硬化症（fALS）病例中有20％是由编码人胞质Cu / Zn超氧化物歧化酶（hSOD1）的基因突变引起的。有效翻译干扰RNA（RNAi）的治疗SOD1-ALS患者的潜力，需要开发无明显脱靶作用且具有可靠生物标志物的载体，以识别足够的靶标参与和正确剂量。使用腺相关病毒血清型9在SOD1 ^G93A小鼠模型中传递针对hSOD1的RNAi ，我们发现鞘内注射治疗性载体通过巨大的水罐能延缓疾病的发作，在末期减少运动神经元死亡的可能性高达88％，并且延长了SOD1 ^G93A的中位生存期小鼠最多可增加42％。据我们所知，这是第一份证明没有与hSOD1沉默相关的显着脱靶效应的报告，这为这种方法的特异性提供了进一步的信心。我们还报告了脑脊液（CSF）hSOD1蛋白水平的测量，作为有效剂量和hSOD1敲除功效的生物标记。在一起，这些数据为临床治疗载体的安全性提供了进一步的信心。CSF生物标记物将是一种有用的生物活性测定方法，可用于翻译成人类临床试验。