rAAV-mediated knockdown for Huntington's disease

亨廷顿病（Huntington 'sdisease，HD）是一种常染色体显性遗传的进行性神经系统疾病。的 神经病理学症状似乎是由进行性功能障碍和新生纹状体死亡引起的。 神经元和/或皮质-纹状体束。HD基因于1993年首次被描述，基因缺陷是 鉴定为在编码以下的基因的外显子1中高于阈值水平的一系列CAG重复的扩增： 一种叫做亨廷顿蛋白的蛋白质随后，在其他八个基因中也发现了类似的重复扩增 当三核苷酸扩增达到阈值时， 每种疾病的典型特征。这些不同的疾病在概念上也有联系，因为像HD一样， 是由中枢神经系统中特定神经元的功能障碍引起的。此外，在所有CAG扩增突变中- 突变蛋白似乎诱导异常的核蛋白聚集，称为 神经元核内包涵体在HD中，最好的数据似乎表明，功能的毒性增加和 亨廷顿蛋白突变形式中某些正常功能的丧失导致神经病理学。因此，我们的建议 目的是使用重组腺相关病毒载体来递送基因编码构建体， 纹状体神经元中的亨廷顿蛋白。纹状体亨廷顿蛋白的长期敲低将检验以下假设： 亨廷顿蛋白表达的减少应该限制转导的神经元中神经元核内包涵体的形成。 神经元，从而减缓HD小鼠模型的疾病进展。我们将使用小干扰RNA 在纹状体神经元中敲低亨廷顿蛋白。此外，我们提出了两种方法来测试 假设正常的亨廷顿蛋白表达是有益的。首先，我们将比较亨廷顿蛋白 在敲入HD小鼠和转基因HD小鼠中敲低。由于转基因HD小鼠仍然表达 正常数量的小鼠亨廷顿蛋白，我们的假设预测，亨廷顿蛋白敲低将更多 与只具有突变亨廷顿蛋白的基因敲入HD小鼠相比， 表情其次，目前还不清楚纹状体功能障碍是否起源于细胞自主的方式， 纹状体神经元或由突变的亨廷顿蛋白诱导的皮质-纹状体功能障碍引起。我们将直接测试 这一假设通过转导皮质区与纹状体区。我们将使用纹状体数量的减少 神经元核包涵体和逆转已知的转录变化作为我们的初步筛选有益的 效果，其次是详细的功能分析的运动行为作为衡量这些策略的成功。

Huntington's disease (HD) is an autosomal dominant inherited progressive neurological disorder. The neuorpathological symptoms appear to be caused by progressive dysfunction and death of neostriatal neurons and/or the cortico-striatal tract. The HD gene was first described in 1993 and the gene defect was identified as an expansion of a series of CAG repeats above a threshold level in exon 1 of a gene encoding a protein called huntingtin. Subsequently, similar repeat expansions have been identified in eight other genes that are known to cause different neurological disorders when the trinucleotide expansions reach thresholds typical for each disease. These different disorders are also conceptually linked because, like HD, symptoms are caused by the dysfunction of specific neurons in the CNS. Moreover, in all CAG expansion mutation- induced disorders, the mutant protein seems to induce abnormal nuclear protein aggregations termed neuronal intranuclear inclusions. In HD, the best data seem to indicate that both a toxic gain of function and a loss of some normal function in the mutant form of huntingtin leads to neuropathology. Thus, our proposal aims to use recombinant adeno-associated viral vectors to deliver genes encoding constructs to knock-down huntingtin in striatal neurons. Long-term knock-down of striatal huntingtin will test the hypothesis that reduced huntingtin expression should limit the formation of neuronal Intranuclear inclusions in transduced neurons and thereby slow disease progression in mouse models of HD. We will use small interfering RNAs (siRNAs) to knock-down huntingtin in striatal neurons. Moreover, we propose two ways to test the hypothesis that normal huntingtin expression is beneficial.. First, we will compare the effects of huntingtin knock-down in both knock-in HD mice and transgenic HD mice. Since transgenic HD mice still express the normal amount of mouse huntingtin, our hypothesis predicts that huntingtin knock-down will be more beneficial in the transgenic mice compared to the knock-in HD mice that have only mutant huntingtin expression. Second, it is unclear whether striatal dysfunction originates in a cell autonomous fashion in striatal neurons or is caused by mutant huntingtin-induced cortico-striatal dysfunction. We will directly test this hypothesis by transducing cortical areas vs. striatal areas. We will use reduction in the amount of striatal neuronal nuclear inclusions and reversal of known transcriptional changes as our initial screen for beneficial effects followed by detailed functional analysis of motor behavior as metric of success of these strategies.