Critical analysis of glycosphingolipid pathways in aging and Parkinsons disease

 性状（由申请方提供）：鞘糖脂是许多细胞过程所必需的，在膜中富集，并通过酸性水解酶的作用在核内体和溶酶体中进行催化降解。GBA编码溶酶体酶葡糖脑苷脂酶（GCase），其负责鞘糖脂底物葡糖神经酰胺（GluCer）和葡糖鞘氨醇（GluSph）的水解。GBA基因突变是帕金森病（PD）和相关α-突触核蛋白病的最高已知遗传风险因素。我们的初步数据显示，在散发性PD中，人脑中GluSph的水平增加。此外，我们表明，GCase活性降低，鞘糖脂水平增加，在大脑中的正常老化。鞘糖脂水平升高对衰老和散发性PD中神经元健康的影响尚不清楚。在R 01申请中，我设计了实验来测试神经细胞中鞘糖脂升高与衰老和PD的相关性。在具体目标1中，我们假设鞘糖脂水平的改变诱导神经元功能障碍和变性的易感性。我们将在体外调节小鼠和人类神经元中的GluSph水平，以确定神经元对PD应激源的脆弱性（包括增加的α-突触核蛋白负荷）是否改变。我们将 还确定是否在人PD患者成纤维细胞和神经元中检测到GCase降低和GluSph水平升高，因为这种改变可能代表PD的新生物和药效学标志物。在具体目标2中，我们假设减少衰老和PD中鞘糖脂的蓄积可以防止α-突触核蛋白的聚集和毒性。我们将确定在两种α-突触核蛋白病啮齿动物模型中鞘糖脂通路的稳态是如何改变的，我们将在这些相同的体内模型中通过增加神经元GCase水平来测量操纵鞘糖脂通路的效果。这些实验将对鞘糖脂通路在PD和相关α-突触核蛋白病中的作用进行关键分析，并应为开发新型治疗药物以改善鞘糖脂代谢和预防神经变性提供新靶点。

 DESCRIPTION (provided by applicant): Glycosphingolipids are essential for many cellular processes, are enriched in membranes, and undergo catabolism in endosomes and lysosomes through the action of acid hydrolases. GBA encodes the lysosomal enzyme glucocerebrosidase (GCase), which is responsible for the hydrolysis of the glycosphingolipid substrates glucosylceramide (GluCer) and glucosylsphingosine (GluSph). GBA gene mutations are the highest known genetic risk factor for developing Parkinson's disease (PD) and related α-synucleinopathies. Our preliminary data shows that levels of GluSph are increased in the human brain in sporadic PD. Moreover, we show that GCase activity is reduced, and glycosphingolipid levels are increased in the brain in normal aging. The consequences of increased glycosphingolipid levels on neuronal health in aging and in sporadic PD are not known. In this R01 application I have designed experiments to test the relevance of elevated glycosphingolipids in neural cells in aging and PD. In Specific Aim 1 we hypothesize that altered levels of glycosphingolipids induce neuronal dysfunction and susceptibility to degeneration. We will modulate levels of GluSph in mouse and human neurons in vitro to determine whether neuronal vulnerability to PD-stressors, including increased α-synuclein loads, is altered. We will also establish whether reduced GCase and increased GluSph levels are detected in human PD patient fibroblasts and neurons as such alterations may represent novel bio- and pharmacodynamic- markers for PD. In Specific Aim 2 we hypothesize that reducing the accumulation of glycosphingolipids in aging and PD can prevent the aggregation and toxicity of α-synuclein. We will determine how the homeostasis of glycosphingolipid pathways are altered in two rodent models of α-synucleinopathy, and we will measure the effect of manipulating glycosphingolipid pathways by increasing neuronal GCase levels, in these same in vivo models. These experiments will provide critical analysis of the role of glycosphingolipid pathways in PD and related α-synucleinopathies, and should provide new targets for the development of novel therapeutics to improve glycosphingolipid metabolism and prevent neurodegeneration.