Progranulin: A Novel Gene in Gaucher Diseases

项目摘要 戈谢病（GD）是一种遗传性疾病，由GBA 1基因突变引起， β-葡萄糖脑苷脂酶（GCase）的酶活性;然而，具有相同GCase突变的患者可能 有显著的前列腺素疾病表现，从危及生命的表现到几乎 无症状。据认为，修饰基因是负责异常多样的表型 GBA 1基因突变相同的患者。因此，GD中新修饰基因的鉴定将 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。 和GD的治疗靶点。我们以前的报告表明，颗粒蛋白前体（PGRN）是治疗性的， 炎症性关节炎（Tang，et al. Science，2011）促使我们确定PGRN是否也发挥作用 使用卵清蛋白（OVA）激发的哮喘模型， GRN（PGRN编码基因）是GD中的一个新基因。PGRN敲除小鼠显示GD的典型特征， 包括多器官高雪氏细胞出现“皱薄纸”状，溶酶体呈管状 在巨噬细胞中转化。此外，GD患者的血清PGRN水平显著较低， 与健康对照组相比，较低的PGRN水平与GRN变体显著相关 在GD患者中发现（Jian等人，EBioMedicine，2016 a）。PGRN直接与GCase结合，其缺陷 导致GCase在细胞质中的聚集和溶酶体定位的缺陷。98 C- PGRN的末端氨基酸（称为Pcgin）是与GCase结合所需且足够的。Pcgin 有效地改善了GD患者成纤维细胞和OVA攻击的GD模型中的疾病表型（Jian， 等人，EBioMedicine，2016 b）。目前，治疗神经病性GD的医疗需求迫切未得到满足， 用于GD的酶替代疗法不能渗透到脑中。令人兴奋的是，我们的初步数据显示， Pcgin能穿过血脑屏障，对神经源性GD有一定的治疗作用。为了努力 为了阐明PGRN和Pcgin介导的抗GD治疗作用的分子机制，我们 进行了无偏蛋白质组学筛选，分离出蛋白质二硫键异构酶A3（PDIA 3） 作为PGRN和Pcgin共结合分子。此外，PDIA 3的缺失废除了Pcgin在人结肠癌中的治疗作用。 GD患者成纤维细胞。本申请的假设是PGRN是GD中的新型修饰剂，并且其 Pcgin衍生物是治疗GD的药物。本研究的具体目的是：（1）确定 PGRN及其衍生物Pcgin在GD中的作用，特别是对神经性GD的作用;和（2）阐明PGRN及其衍生物Pcgin在GD中的细胞作用， 以及PGRN和Pcgin调节GCase和GD的分子机制，特别关注它们的作用。 在GD中与PDIA 3相互作用。完成拟议的研究不仅将PGRN作为一种新颖的 GD的修饰物，为GD发病机制中的分子事件提供了新的见解，但也可能导致 用于治疗GD，特别是神经性GD的新生物制剂的开发。

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.