Progranulin: A Novel Gene in Gaucher Diseases

项目摘要 高谢病(GD)是一种由GBA1基因突变导致的遗传病 β-葡萄糖脑苷酶(GCase)的酶活性；然而，具有相同GCase突变的患者可能 有不同程度的疾病表现，从危及生命的表现到几乎 没有任何症状。人们认为修饰基因是导致异常不同的表型的原因。 在具有相同GBA1突变的患者中。因此，在GD Will中发现新的修饰基因 为了解GD的发病机制和寻找新的诊断方法提供了宝贵的信息 以及GD的治疗靶点。我们之前的报告中提到普罗布林(PGRN)可以治疗 炎症性关节炎(Tang，et al.科学，2011)促使我们确定PGRN是否也起到了作用 在肺部炎症中使用卵蛋白(OVA)激发哮喘模型，这导致了这一意想不到的发现 GRN(编码PGRN的基因)是GD中的一个新基因。PGRN基因缺失小鼠表现出典型的GD特征， 包括多器官内高雪氏细胞的“皱纹纸片”状外观，管状溶酶体 巨噬细胞的转化。此外，GD患者血清PGRN水平在以下情况下显著降低 与健康对照组相比，较低的PGRN水平与GRN变异显著相关 在GD患者中发现(Jian等人，EBioMedicine，2016a)。PGRN与GCase的直接结合及其缺陷 结果GCase在细胞质内聚集，在溶酶体定位上出现缺陷。此外，98℃- PGRN的末端氨基酸，称为Pcgin，是与GCase结合所必需的，也是足够的。加注 有效地改善GD患者成纤维细胞和OVA激发的GD模型的疾病表型(Jian， EBioMedicine等人，2016b)。治疗神经性GD有一个紧急的未得到满足的医疗需求，因为目前 酶替代疗法治疗GD不能透入大脑。令人兴奋的是，我们的初步数据显示 Pcgin可穿透血脑屏障，对神经性GD也有治疗作用。为了努力 阐明PGRN和Pcgin治疗GD的分子机制 进行蛋白质组学无偏筛选，分离出蛋白质二硫键异构酶A3(PDIA3) 作为PGRN和Pcgin共同结合的分子。此外，PDIA3的缺失取消了Pcgin的治疗作用 GD患者成纤维细胞。这一应用的假设是，PGRN是一种新的GD修饰物，其 其衍生物Pcgin对GD有治疗作用。具体目的是：(1)确定其治疗作用 PGRN及其衍生物Pcgin在GD中的作用，特别是对神经病理性GD的作用；以及(2)阐明细胞 以及PGRN和Pcgin调节GCase和GD的分子机制，尤其是它们的 与PDIA3在GD中的相互作用拟议研究的完成不仅将使PGRN成为一部小说 GD的修饰物，为了解GD发病机制中的分子事件提供了新的视角，但也可能导致 治疗GD，特别是神经病理性GD的新型生物制剂的开发。

Project Summary Gaucher disease (GD) is a genetic disease caused by mutations in the GBA1 gene which result in reduced enzymatic activity of β-glucocerebrosidase (GCase); however, patients with the same GCase mutations may have significant variably in disease presentation, ranging from a life-threatening manifestation to almost asymptomatic. It is believed that the modifier genes are responsible for the extraordinarily diverse phenotypes among patients harboring identical GBA1 mutations. Thus, identification of new modifier genes in GD will provide invaluable information in understanding the pathogenesis of GD and in searching for novel diagnostic and therapeutic targets for GD. Our previous report that progranulin (PGRN) is therapeutic against inflammatory arthritis (Tang, et al. Science, 2011) prompted us to determine whether PGRN also played a role in lung inflammation using ovalbumin (OVA)-challenged asthma model, which led to the unexpected discovery of GRN (the gene encoding PGRN) as a novel gene in GD. PGRN null mice display typical features of GD, including “wrinkled tissue paper” appearance of Gaucher cells in multiple organs, and tubular-like lysosome transformation in macrophages. In addition, serum PGRN levels of GD patients are significantly lower when compared to healthy controls, and lower PGRN level was significantly associated with the GRN variants identified in GD patients (Jian, et al, EBioMedicine, 2016a). PGRN binds directly to GCase, and its deficiency results in aggregation in the cytoplasm and defects in the lysosomal localization of GCase. Additionally, 98 C- terminal amino acids of PGRN, referred to as Pcgin, are required and sufficient for the binding to GCase. Pcgin effectively ameliorates the disease phenotype in GD patient fibroblasts and OVA-challenged GD model (Jian, et al, EBioMedicine, 2016b). There is an urgent unmet medical need for treating neuropathic GD, since current enzyme replacement therapy for GD cannot penetrate into brain. Excitingly, our preliminary data revealed that Pcgin could cross blood brain barrier and might be also therapeutic against neuropathic GD. In an effort to elucidate the molecular mechanism underlying PGRN- and Pcgin-mediated therapeutic effect against GD, we performed an unbiased proteomics screen, which led to the isolation of protein disulfide-isomerase A3 (PDIA3) as a PGRN and Pcgin co-bound molecule. In addition, loss of PDIA3 abolished Pcgin's therapeutic effects in GD patient fibroblasts. The hypothesis of this application is that PGRN is a novel modifier in GD and its derivative Pcgin is therapeutic against GD. The Specific Aims are: (1) To determine the therapeutic role of PGRN and its derivative Pcgin in GD, in particular against neuropathic GD; and (2) To elucidate the cellular and molecular mechanisms by which PGRN and Pcgin regulate GCase and GD, with special focus on their interactions with PDIA3 in GD. Completion of the proposed research will not only present PGRN as a novel modifier of GD, provide new insight into the molecular events in the pathogenesis of GD, but could also lead to the development of novel biologics for treating GD, in particular neuropathic GD.