Mechanism of Proteotoxicity and Experimental Therapeutic Approaches in Porphyria

卟啉症的蛋白质毒性机制和实验治疗方法

基本信息

批准号：
10445775
负责人：
Bishr Omary
金额：
$ 49.62万
依托单位：
RBHS-ROBERT WOOD JOHNSON MEDICAL SCHOOL
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-20 至 2023-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10445775
关键词：
Abbreviations Acute Acute Intermittent Porphyria Alcohol consumption Aminolevulinic Acid Animal Model Biochemical Bone Marrow Transplantation Brain Cell Culture Techniques Data Deferoxamine Detection Disease Disease Progression Drug Metabolic Detoxication Drug Modelings Drug Screening Drug usage Enzymes Erythropoietic Porphyria Erythropoietic Protoporphyria Event Excretory function Experimental Models Genetic Genetic Diseases Glycine Goals Heme Hepatitis C In Vitro Individual Infection Investigational Therapies Keratin Knowledge Lead Lead Poisoning Light Liver Liver diseases Mediating Methionine Molecular Molecular Profiling Molecular Weight Monitor Mus Mutation Organ Oxidative Stress Oxides Oxidoreductase Pathway interactions Patients Pharmaceutical Preparations Photosensitivity Pigments Porphyrias Porphyrins Propionates Proteins Proteomics Reactive Oxygen Species Role Skin Sodium Dodecyl Sulfate Technology Testing Therapeutic Tissues Toxic effect Toxin Uroporphyrins Work Zebrafish base bone carboxylate cell injury constitutive androstane receptor dimer drug candidate end stage liver disease ferrochelatase high throughput screening improved in vivo Model liver injury methionine sulfoxide methionine sulfoxide reductase monomer mouse model novel novel therapeutics oxidation pre-clinical preclinical study prevent protein aggregation proteotoxicity protoporphyrin IX repaired small molecule success succinyl-coenzyme A tissue injury tool

项目摘要

Project Summary Porphyrias are genetic disorders caused by mutations in enzymes involved in eight sequential biosynthetic conversions that combine glycine and succinyl coenzyme-A in the first enzymatic step to ultimately generate heme. Porphyrin accumulation also occurs in ‘secondary porphyrias’ in association with other diseases such as hepatitis C virus infection. Current major unmet needs with regard to the porphyria disorders include: (a) our present limited understanding of the biochemical mechanism of cell and tissue injury, (b) the molecular triggers of porphyria acute attacks, (c) the reasons why some individuals develop significant organ complications such as end-stage liver disease that requires liver or bone marrow transplantation, while others do not, and (d) the limited availability of drugs to treat the different porphyrias. Our central hypothesis is that the liver is susceptible to light-independent porphyrin-mediated proteotoxic damage that leads to cell and tissue injury in porphyria, and that drugs can be identified that lead to increased or decreased porphyrin accumulation. This hypothesis will be tested by pursuing three interconnected specific aims: (i) Define the mechanism of light-independent porphyrin- induced protein aggregation in internal organs, with a focus on the liver; (ii) Elucidate the mechanism of detoxification of porphyrin-induced proteotoxic damage using in vitro and in vivo models; and (iii) Characterize small molecules that decrease or increase tissue porphyrin accumulation and porphyrin-mediated proteotoxicity. We have assembled extensive preliminary results to support the likely success of our aims, including substantial evidence for porphyrin-mediated protein aggregation that is light-independent, the reversibility of protein aggregation and enzymes that are likely to be involved in reversing protein oxidation, and the use of zebrafish high-throughput screening to identify known drugs that decrease or increase porphyrin accumulation in liver. The drugs that decrease porphyrin accumulation will be tested for their mechanism of action and examined in preclinical porphyria experimental models as drugs that may be repurposed as potential new therapies. In parallel, drugs that increase porphyrin accumulation will be characterized as potential candidate drugs to avoid in patients with porphyria. Completion of our proposed aims provides fundamental knowledge regarding which proteins are prone to porphyrin-mediated oxidation and aggregation, the molecular signatures that define such aggregation, the mechanism of aggregate turnover and disaggregation, whether compounds we characterize are candidates for testing in patients with porphyria, and whether currently used drugs in non-porphyria disorders might need to be avoided or monitored in patients with porphyria. This proposal uses state-of-the-art technologies, multiple biochemical and porphyria animal model tools including zebrafish and mice, and introduces the novel concept of proteotoxicity as an alternative mechanism for porphyria exacerbations and progression that may shed light on genetic modifiers that account for liver disease progression in some patients but not others.

项目摘要卟啉症是由参与八个顺序生物合成的酶突变引起的遗传疾病将甘氨酸和琥珀酰辅酶A结合在第一个酶促步骤中以最终产生的转化血红素。卟啉积累也与其他疾病（例如丙型肝炎病毒感染。目前关于卟啉症疾病的主要未满足需求包括：（a）我们目前对细胞和组织损伤生化机理的了解有限，（b）分子触发器卟啉症急性攻击，（c）某些人出现重大器官并发症的原因作为需要肝脏或骨髓移植的终末期肝病，而其他肝脏则不进行，并且（d）有限的药物可用性治疗不同的卟啉症。我们的中心假设是肝脏易感与光无依赖性的卟啉介导的蛋白毒性损伤，导致卟啉症的细胞和组织损伤，并且可以鉴定出导致卟啉积累增加或减少的药物。这个假设将是通过追求三个相互连接的特定目的测试：（i）定义光独立卟啉的机理诱导内部器官的蛋白质聚集，重点是肝脏；（ii）阐明使用体外和体内模型对卟啉诱导的蛋白毒性损伤进行解毒；（iii）特征降低或增加组织卟啉积累和卟啉介导的蛋白毒性的小分子。我们已经组装了广泛的初步结果，以支持我们目标的可能成功，包括实质性的卟啉介导的蛋白质聚集的证据是光独立的，蛋白质的可逆性可能参与逆转蛋白质氧化的聚集和酶，斑马鱼的使用高通量筛查以鉴定已知药物减少或增加肝素积累。这减少卟啉积累的药物将测试其作用机理，并在临床前卟啉症实验模型作为可能被重新定义为潜在新疗法的药物。在相似的是，增加卟啉积累的药物将被描述为潜在的候选药物，以避免在患有卟啉症患者中。我们提出的目标的完成提供了有关哪种蛋白质容易出现的基本知识卟啉介导的氧化和聚集，定义这种聚集的分子特征，总营业额和分解机制，我们表征的化合物是否是候选者对卟啉症患者进行测试，目前是否需要在非孢子虫疾病中使用药物在卟啉症患者中避免或监测。该建议使用最先进的技术，多个包括斑马鱼和小鼠在内的生化和斑岩动物模型工具，并介绍了新概念蛋白毒性是卟啉症加剧和进展的替代机制关于某些患者肝脏疾病进展的遗传修饰剂，而不是其他患者的肝病进展。