Conditional Models: Non-cell-antonomous Toxicities in HD

描述（由申请人提供）：神经退行性疾病发病机制中的共同主题是广泛表达的突变蛋白可导致脑中神经元亚群的选择性变性。在大多数情况下，这种选择性神经变性的分子和细胞机制仍然不清楚。使用亨廷顿病（HD）作为模型，我们将调查是否选择性变性的纹状体和皮质神经元在HD需要突变亨廷顿（mHt）的毒性起源于这些神经元以外（非细胞自主毒性）。在我们的初步研究中，我们已经开发了两种条件性小鼠模型，其中mHt表达可以在特定的神经元群体中被激活或失活。我们建议使用这些小鼠模型来实现以下三个具体目标：具体目标1。皮质激活小鼠模型和全脑激活小鼠模型的表型分析，以确定非细胞自主毒性是否涉及脆弱的皮质和纹状体神经元的功能障碍和变性。具体目标2。纹状体激活小鼠模型的表型分析，以确定非细胞毒性是否涉及纹状体和皮质神经元的功能障碍和变性。具体目标3。产生全长mHt皮质失活小鼠模型以研究在全长mHt小鼠模型中疾病发病机制中是否需要非细胞自主毒性。总之，我们建议使用一系列新的条件性HD小鼠模型来研究神经元回路在HD发病机制中的作用。我们的研究可能揭示，mHt毒性起源于最脆弱的神经元外，可能需要他们的功能障碍和退化。这种毒性的鉴定将对开发HD以及其他神经退行性疾病的治疗方法具有重要意义。

DESCRIPTION (provided by applicant): A common theme in the pathogenesis of the neurodegenerative diseases is that a widely expressed mutant protein can cause selective degeneration of a subset of neurons in the brain. In most of the cases, the molecular and cellular mechanisms underlying such selective neurodegeneration remain unclear. Using Huntington's disease (HD) as a model, we will investigate whether selective degeneration of the striatal and cortical neurons in HD requires mutant Hungtingtin (mHt) toxicities originated from outside these neurons (non-cell-autonomous toxicities). In our preliminary studies, we have developed two conditional mouse models in which mHt expression can either be activated or inactivated in specific neuronal populations. We propose to use these mouse models to achieve the following three Specific Aims: Specific Aim 1. Phenotypic analyses of the cortical activation mouse model and the whole brain activation mouse model to determine whether non-cell autonomous toxicities are involved in dysfunction and degeneration of the vulnerable cortical and striatal neurons. Specific Aim 2. Phenotypic analyses of the striatal activation mouse model to determine if the non-cellautonomous toxicities are involved in dysfunction and degeneration of the striatal and cortical neurons. Specific Aim 3. Generation of a full length mHt cortical-inactivation mouse model to study whether non-cell autonomous toxicities are required in disease pathogenesis in a full length mHt mouse model. In summary, we propose to use a novel series of conditional mouse models of HD to study the role of neuronal circuitry in HD pathogenesis. Our studies may reveal that mHt toxicities originated from outside the most vulnerable neurons may be required for their dysfunction and degeneration. Identification of such toxicities will have important implications for developing therapeutics for HD as well as for other neurodegenerative diseases.