RILUZOLE MOA: TARGETS FOR IMPROVED NEUROPROTECTIVE DRUGS

描述（由申请人提供）：肌萎缩性侧索硬化症（ALS）是一种侵袭性运动神经元神经退行性疾病，通常在发病后5年内导致进行性肌无力、瘫痪并最终死亡。晚期ALS患者需要广泛的支持性护理，给患者及其家人带来巨大的情感和经济负担。阿曲唑是目前批准用于治疗ALS的唯一药物，仅为ALS患者的预期寿命提供2至3个月的适度延长，并且肝毒性是限制药物使用的显著副作用。生物化学和细胞研究已经表明利鲁唑作用的多种潜在靶点，但是该药物的精确分子作用机制（MOA）仍然不清楚。更全面地了解利鲁唑的分子靶点对于指导发现更安全和更有效的ALS疗法具有重要价值。 在秀丽隐杆线虫模型中的遗传学研究已经成功地用于鉴定许多人类药物的靶点和机制途径。初步研究表明利鲁唑对C. elegans和多个独立的耐药基因突变体已经被分离出来。SBIR第一阶段项目将完成这些利鲁唑抗性等位基因在C. elegans，目的是表征利鲁唑的MOA并鉴定可用于治疗发现工作的利鲁唑靶标。将追求两个具体目标：（1）利鲁唑抗性等位基因的遗传作图将采用遗传重组作图和单核苷酸多态性分析的组合。(2)利鲁唑耐药基因的鉴定。根据遗传图谱结果，将结合候选基因测序和遗传转化实验（如需要）来鉴定赋予利鲁唑耐药性的特定突变。利鲁唑耐药基因的分子表征将鉴定利鲁唑在具有良好表征的神经系统的活体模型动物中的作用的一种或多种途径。随后的II期工作将（a）鉴定和评估同源哺乳动物基因的功能，（B）开发和实施新的生物测定法，以合理发现ALS和其他神经退行性疾病的下一代治疗方法。

DESCRIPTION (provided by applicant): Amyotrophic lateral sclerosis (ALS) is an aggressive neurodegenerative disease of motor neurons that results in progressive muscle weakness, paralysis, and ultimately death, usually within five years of disease onset. Late stage ALS patients require extensive supportive care, placing immense emotional and economic burdens on patients and their families. Riluzole, the only drug currently approved for the treatment of ALS, provides only a modest extension of 2 to 3 months in life expectancy for ALS patients, and hepatotoxicity is a significant side effect limiting the drug's use. Biochemical and cellular studies have suggested a wide variety of potential targets for riluzole action, but the precise molecular mechanism of action (MO A) of this drug remains poorly defined. A more complete understanding of riluzole's molecular target(s) would be of great value in guiding the discovery of safer and more effective therapies for ALS. Genetic studies in the model nematode Caenorhabditis elegans have been successfully utilized to identify the targets and mechanistic pathways of a number of human Pharmaceuticals. Preliminary studies have demonstrated a significant effect of riluzole on C. elegans, and multiple independent genetic mutants resistant to the drug have been isolated. This Phase I SBIR project will complete the genetic analysis of these riluzole-resistance alleles in C. elegans, with the goal of characterizing riluzole's MOA and identifying riluzole targets that can be exploited for therapeutic discovery efforts. Two specific aims will be pursued: (1) Genetic mapping of the riluzole-resistance alleles will employ a combination of genetic recombination mapping and single-nucleotide polymorphism analysis. (2) Identification of the riluzole-resistance gene(s). Based on the genetic mapping results, a combination of candidate gene sequencing and, as needed, genetic transformation experiments will be used to identify the specific mutations conferring riluzole resistance. The molecular characterization of the riluzole-resistance gene(s) will identify one or more pathways for riluzole's action in a living model animal with a well-characterized nervous system. Subsequent Phase II efforts will (a) identify and evaluate the function of homologous mammalian genes, and (b) develop and implement new bioassays for the rational discovery of next-generation therapeutics for ALS and other neurodegenerative diseases.