The cause and effect of reduced ò-glucocerebrosidase activity in the setting of progranulin deficiency

项目摘要 拟议研究项目的目的是进一步了解颗粒蛋白前体（GRN）和β- 葡萄糖脑苷脂酶（GCase）相互作用以及这些相互作用在额颞叶痴呆（FTD）中的意义 是由颗粒蛋白前体突变引起的额颞叶痴呆是早发性痴呆的主要原因， 功能丧失的颗粒蛋白前体突变是三种主要遗传原因之一。颗粒蛋白原是一种分泌的溶酶体- 常驻糖蛋白，并且缺乏引起患者和小鼠中的溶酶体功能障碍。前颗粒蛋白增强 治疗FTD-GRN有希望，但交付是一个问题，安全性尚不清楚。这 强调了继续寻找具有已知安全性特征的靶向治疗剂的迫切需要。因此 减少颗粒蛋白前体缺陷诱导的溶酶体功能障碍的靶向治疗可能具有治疗作用。 预防或延迟FTD-GRN的益处。 为了了解由颗粒蛋白前体缺乏引起的潜在溶酶体功能障碍，我们的实验室 表征了FTD-GRN患者脑中几种溶酶体酶的活性， 缺陷小鼠我们发现神经元GCase（一种溶酶体酶）的活性降低，而其他溶酶体酶的活性降低。 酶显示出增加的活性。GCase是一个有趣的目标，因为它已知参与了 神经退行性疾病，因为GCase突变是帕金森病的主要遗传风险因素， 戈谢病的单基因原因，一种具有神经退行性亚型的溶酶体贮积病。 FTD-GRN中的GCase缺陷似乎是由于糖基化损伤引起GCase聚集。 该提案将确定颗粒蛋白前体缺乏是否会损害GCase运输，导致溶酶体减少， 本地化总体假设是受损的前颗粒蛋白介导的GCase运输 导致溶酶体功能障碍和由颗粒蛋白前体缺乏引起的其它缺陷。这项建议 将测试以下两个目标：（1）确定颗粒蛋白前体如何调节GCase的运输，以及（2）确定 如果GCase缺陷导致溶酶体功能障碍和由颗粒蛋白前体缺陷引起的其他缺陷。更 需要进行工作以了解前颗粒蛋白-GCase相互作用的细节和作用。我会先确定 负责GCase相互作用的颗粒蛋白前体结构域，然后将测试这种相互作用对 GCase稳定性和溶酶体运输。然后，我将确定增加GCase是否足以减少 溶酶体功能障碍和行为异常。 这个建议将有助于我的科学和专业发展，帮助我：1）提高能力 在严格实验设计和假设检验中，2）改进已知的实验技术并开发 翻译研究的技能，以及3）获得向科学和非科学受众展示数据的经验。

PROJECT SUMMARY The objective of the proposed research project is to further understand how progranulin (GRN) and β- glucocerebrosidase (GCase) interact and the implications of these interactions in frontotemporal dementia (FTD) caused by progranulin mutations. Frontotemporal dementia is a leading cause of early-onset dementia, and loss- of-function progranulin mutations are one of three main genetic causes. Progranulin is a secreted and lysosome- resident glycoprotein, and deficiency causes lysosomal dysfunction in patients and in mice. Progranulin-boosting therapies have promise for treating FTD-GRN, but delivery is an issue and the safety profile is unclear. This underscores a critical need to continue to search for targeted therapeutics with known safety profiles. Thus, a targeted therapy that reduces progranulin deficiency-induced lysosomal dysfunction may have therapeutic benefits for preventing or delaying FTD-GRN. In order to understand the underlying lysosomal dysfunction caused by progranulin deficiency, our lab has characterized the activities of several lysosomal enzymes in the brains of FTD-GRN patients and progranulin- deficient mice. We found decreased activity of neuronal GCase, a lysosomal enzyme, whereas other lysosomal enzymes show increased activity. GCase is an interesting target because of its known involvement in neurodegenerative disease, as GCase mutations are the leading genetic risk factor for Parkinson disease and the monogenic cause of Gaucher disease, a lysosomal storage disease with neurodegenerative subtypes. GCase deficiency in FTD-GRN appears to be due to an impairment in glycosylation causing GCase aggregation. This proposal will determine if progranulin deficiency impairs GCase trafficking, resulting in decreased lysosomal localization. The overarching hypothesis is that impaired progranulin-mediated GCase trafficking contributes to lysosomal dysfunction and other deficits caused by progranulin deficiency. This proposal will test the following two aims: (1) Determine how progranulin regulates trafficking of GCase and (2) Determine if GCase deficits contribute to lysosomal dysfunction and other deficits caused by progranulin deficiency. More work is needed to understand the specifics and effects of the progranulin-GCase interaction. I will first determine the domain of progranulin responsible for GCase interaction and will then test the effects of this interaction on GCase stability and lysosomal trafficking. I will then determine if increasing GCase is sufficient to reduce lysosomal dysfunction and behavioral abnormalities in progranulin-deficient mice. This proposal will facilitate my scientific and professional development by helping me: 1) improve competency in rigorous experimental design and hypothesis testing, 2) refine known experimental techniques and develop skills for translational research, and 3) gain experience presenting data to both scientific and lay audiences.