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

• 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
• 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

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 卟啉病是由参与八种连续生物合成的酶突变引起的遗传性疾病。 在第一个酶促步骤中结合联合收割机甘氨酸和琥珀酰辅酶-A以最终产生 血红素卟啉积累也发生在与其他疾病，如 丙型肝炎病毒感染目前在卟啉症方面尚未满足的主要需求包括： 目前对细胞和组织损伤的生化机制的理解有限，（B）分子触发物 卟啉病急性发作的原因，（c）为什么有些人发展显着的器官并发症， 作为需要肝脏或骨髓移植的终末期肝病，而其他人则不需要，以及（d） 治疗不同卟啉症的药物有限。我们的核心假设是肝脏容易受到 光非依赖性卟啉介导的蛋白毒性损伤，导致卟啉症中的细胞和组织损伤，和 可以鉴定导致卟啉积累增加或减少的药物。这一假设将是 通过追求三个相互关联的具体目标进行测试：（i）定义光独立卟啉的机制- 诱导内脏器官中的蛋白质聚集，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;以及（iii）表征 减少或增加组织卟啉积累和卟啉介导的蛋白毒性的小分子。 我们已经收集了广泛的初步结果，以支持我们的目标可能取得的成功，包括大量的 证明卟啉介导的蛋白质聚集是光依赖性的，蛋白质的可逆性 聚集和酶，可能参与逆转蛋白质氧化，以及使用斑马鱼 高通量筛选以鉴定降低或增加肝脏中卟啉积累的已知药物。的 减少卟啉积累的药物将被测试其作用机制，并在 临床前卟啉症实验模型作为药物，可能被重新用作潜在的新疗法。在 同时，增加卟啉积累的药物将被表征为潜在的候选药物，以避免 在卟啉症患者身上 我们提出的目标的完成提供了关于哪些蛋白质倾向于 卟啉介导的氧化和聚集，定义这种聚集的分子特征， 聚合物周转和解聚的机制，我们所描述的化合物是否是 在卟啉症患者中进行测试，以及目前用于非卟啉症疾病的药物是否需要 避免或监测卟啉症患者。该提案使用了最先进的技术， 生物化学和卟啉病动物模型工具，包括斑马鱼和小鼠，并介绍了新的概念 蛋白毒性作为卟啉病恶化和进展的替代机制， 遗传修饰剂在某些患者中导致肝病进展，但在其他患者中则不然。