CHANGING TAU PROTEIN LEVELS AND TAU PROTEIN ISOFORMS IN MOUSE MODELS OF DEMENTIA

蛋白质聚集物的堆积是神经退行性疾病的特征之一。这些蛋白质是如何导致疾病的，以及它们随后如何被清除，仍然是一个谜。Tau是一种微管结合蛋白，是一种聚集性蛋白，存在于多种神经退行性综合征中，包括额颞叶痴呆(FTD)、阿尔茨海默病(AD)、进行性核上性瘫痪(PSP)和皮质基底节变性(CBD)。了解tau介导的神经变性可能会导致这些疾病的重要治疗策略。我们的目标是研究降低tau水平和降低4R：3Rtau比率如何影响痴呆小鼠模型的行为和病理异常。 先前的研究表明，tau基因敲除的动物可以保护小鼠免受淀粉样β蛋白诱导的行为异常的影响。我们的目标是测试减少老年动物体内的老鼠tau是否也能提供保护。Tau基因的一些突变会导致FTD，导致选择性剪接的变化和4R：3R tau水平的增加。N279K FTD小鼠模型复制了剪接缺陷和行为病理改变。我们的目标是测试逆转成年N279K的剪接缺陷是否可以 逆转行为和病理改变。 为了降低tau的mRNA和蛋白水平，我们将向沐浴大脑和脊髓的脑脊液中注入反义寡核苷酸。这些寡核苷酸激活核糖核酸酶H并降解tau mRNA。为了降低4R：3R tau比率，我们将使用类似的反义寡核苷酸策略，但反义寡核苷酸旨在促进外显子10的排除(从而降低4R：3R比率)，而不是减少tau mRNA。我们提供了一组在体外降低tau mRNA的寡核苷酸和另一组在体外降低4R：3R比率的寡核苷酸的初步证据。在确定这些寡核苷酸在脑室注射后的疗效后，我们将用减少小鼠tau mRNA和蛋白的寡核苷酸治疗J20 APP小鼠，并用通过改变tau剪接来降低4R：3R比率的寡核苷酸治疗N279K tau小鼠。我们预计，这些寡核苷酸将防止在这些模型中看到的行为和病理变化。这些数据将为患者采取类似的治疗策略奠定基础。

Accumulation of proteinaceous aggregates is one of the defining hallmarks of neurodegenerative diseases. How these proteins cause disease and how they are subsequently cleared has remained an enigma. Tau, a microtubule binding protein, is one such aggregated protein found in multiple neurodegenerative syndromes including Frontotemporal dementia (FTD), Alzheimer's disease (AD), Progressive Supranuclear Palsy (PSP), and Corticobasalganglionic Degeneration (CBD). Understanding tau mediated neurodegeneration may lead to important therapeutic strategies for these disorders. Our goal is to study how decreasing tau levels and decreasing 4R:3R tau ratios affects the behavioral and pathological abnormalities in mouse models of dementia. Previous studies demonstrate that tau knockout animals are protected from amyloid beta induced behavioral abnormalities in mice. Our goal is to test whether decreasing mouse tau in older animals will also provide protection. Some mutations in tau that cause FTD lead to changes in alternative splicing and increased levels of 4R:3R tau. An N279K FTD mouse model replicates the splicing defect and behavioral pathological changes. Our goal is to test whether reversing the splicing defect in an adult N279K can reverse the behavioral and pathologic changes. In order to decrease tau mRNA and protein levels, we will infuse antisense oligonucleotides into the cerebral spinal fluid that bathes the brain and spinal cord. These oligos activate RNAse H and degrade tau mRNA. To decrease 4R:3R tau ratios, we will use a similar antisense oligo strategy, but with antisense oligos designed to promote exclusion of exon 10 (and thus decrease 4R:3R ratio) rather than decreasing tau mRNA. We show preliminary evidence for a set of oligos that decrease tau mRNA in vitro and for another group of oligos that decrease 4R:3R ratios in vitro. After establishing the efficacy of these oligos following intraventricular infusion, we will treat J20 APP mice with oligos that decrease mouse tau mRNA and protein and treat N279K tau mice with oligos that decrease 4R:3R ratios by changing tau splicing. We anticipate that these oligos will prevent the behavioral and pathological changes seen in these models. These data would form the basis for a similar treatment strategy in patients.