Treating AT deficiency with drugs that modulate the proteoatasis network

项目摘要(见说明)：经典形式的抗胰蛋白酶缺乏症(ATD)是肝病最常见的遗传原因之一。肝移植是目前治疗ATD所致严重肝病的唯一方法。与ATD相关的肝病的特征是典型的慢性纤维化，导致肝硬变和肝细胞过度增殖，从而易于发生肝细胞癌。这种病理改变归因于突变的AT-Z的蛋白毒性效应，它聚集在肝细胞的内质网(ER)中，这是突变的ATZ的聚合性倾向所特有的一种毒性获得性作用机制。我的实验室已经阐明了肝细胞应对内质网中ATZ积聚的蛋白毒性效应的潜在机制，包括一套独特的细胞内降解途径(蛋白酶体和自噬)和一套独特的被特异性激活的信号通路(自噬、NFKB、ER和线粒体半胱氨酸酶，但不包括未折叠的蛋白反应)。我们的工作假设是，利用这些自然发生的、可能具有保护性蛋白平衡调节机制的药物策略将对ATD引起的肝病产生治疗作用。最近，我们通过在ATD小鼠模型中证明自噬增强剂卡马西平(CBZ)促进ATZ的降解，减少肝脏ATZ负荷和肝纤维化来验证这一假说。在本申请中提出的工作中，我们将通过调查其他可能对自噬或蛋白酶体系统起作用的候选药物，以及可能通过对细胞转录组的广泛作用而影响蛋白平衡网络的候选药物，进一步探讨这一假设。该项目还将利用基于线虫ATD模型的高含量筛选平台，以及计算药理学分析，以发现更多的治疗候选药物。最后，我们将研究其他细胞反应通路，如NFKB信号、caspase12、SIDT2和PIS激酶，在ATD的病理效应中的作用，以确定这些通路是否可以被开发为未来的新治疗策略。

PROJECT SUMMARY (See instructions): The classical form of al antitrypsin deficiency (ATD) is one of the most common genetic causes of liver disease. Liver transplantation represents the only treatment currently available for severe liver disease due to ATD. The liver disease associated with ATD is characterized by a stereotypical chronic fibrosis leading to cirrhosis and hepatocyte hyper-proliferation that predisposes to hepatocellular carcinoma. This pathology is attributed to the proteotoxic effect of mutant AT Z that accumulates in the endoplasmic reticulum (ER) of liver cells, a gain-of-toxic function mechanism specific for the polymerogenic tendencies of mutant ATZ. My lab has elucidated the potential mechanisms by which liver cells cope with the proteotoxic effects of ATZ accumulation in the ER including a distinct set of intracellular degradation pathways (proteasomal and autophagic) and a distinct set of signaling pathways that are specifically activated (autophagy, NFKB, ER- and mitochondrial-caspases but not the unfolded protein response). Our working hypothesis is that pharmacological strategies which capitalize on these naturally occurring, presumably protective proteostasis regulatory mechanisms will have a therapeutic effect on the liver disease caused by ATD. Recently, we validated this hypothesis by showing that an autophagy enhancer drug , carbamazepine (CBZ), promotes degradation of ATZ, reduces the hepatic ATZ load and hepatic fibrosis in vivo in a mouse model of ATD. In the work proposed in this application we will pursue this hypothesis further by investigating other drug candidates with putative actions specifically on the autophagy or on the proteasomal system as well as drug candidates such as histone deacetylase inhibitors which may affect the proteostasis network by broad actions on the cellular transcriptome The project will also capitalize on a C. elegans ATD model-based high content screening platform together with computational pharmacological analyses to discover additional therapeutic candidates. Finally, we will investigate the role of other cellular response pathways, such as NFKB signaling, caspase 12, SIDT2 and PIS kinase, in the pathologic effects of ATD to determine whether these pathways could be exploited for novel therapeutic strategies in the future.