Targeting the IGF-1/insulin signaling pathway to treat mtDNA disease

靶向IGF-1/胰岛素信号通路治疗线粒体DNA疾病

• 批准号: 9765341
• 负责人: Marc Vermulst
• 金额: $ 29.98万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9765341
• 关键词: ATP Synthesis Pathway; Adult; Affect; Aging; Alleles; Ally; Animal Model; Apoptosis; Autophagocytosis; Biological Process; Biology; Blindness; CRISPR/Cas technology; Caenorhabditis elegans; Cells; Child; Communities; Consumption; DNA polymerase gamma; Data; Disease; Enzymes; Etiology; FRAP1 gene; Functional disorder; Genes; Genetic; Genetic Engineering; Genome; Goals; Hand; Health; Human; Inherited; Insulin Signaling Pathway; Insulin-Like Growth Factor I; Libraries; Longevity; Mammals; Medicine; Microscopy; Mitochondria; Mitochondrial DNA; Mitochondrial Diseases; Mitochondrial Proteins; Modeling; Molecular; Molecular Biology; Mus; Muscle function; Muscular Atrophy; Mutation; Myopathy; Nematoda; Nerve Degeneration; Organelles; Organism; Pathology; Pathway interactions; Patients; Pharmaceutical Preparations; Play; Positioning Attribute; Problem Solving; Production; Protein Biosynthesis; Proteins; Quality Control; RNA Interference; RNA interference screen; Respiration; Role; Severities; Signal Transduction; Testing; Therapeutic; Time; Tubular formation; age related; combat; deafness; design; experimental study; flexibility; follow-up; insight; insulin signaling; mitochondrial DNA mutation; mitochondrial dysfunction; mitochondrial genome; mouse model; mutant; neuromuscular; novel; prevent; programs; reduce symptoms; response; therapeutic evaluation; trend; tumor progression

ABSTRACT Genetic instability of the mitochondrial genome (mtDNA) plays an important role in human aging and disease. For example, mtDNA instability causes blindness, deafness, myopathy and severe encephalomyopathy in children, and contributes to muscle wasting, cancer progression, and neurodegeneration in aging adults. To this day though, no child has ever been cured or successfully treated for an inherited mtDNA disease, nor does a treatment exist for the mtDNA component of age-related diseases. To successfully design a therapeutic strategy, it will be important to identify molecular mechanisms that can either increase or decrease the pathology that is caused by mtDNA instability. We may then manipulate these pathways with drugs to prevent or delay these diseases. Identifying these pathways requires a flexible animal model that is well suited for “discovery experiments”; therefore, we created a new animal model of mtDNA instability in the nematode C. elegans. Using CRISPR/Cas9 technology, we created an error prone allele of DNA polymerase gamma (polg- 1D207A), the enzyme that replicates the mitochondrial genome. Worms that carry this allele display an elevated rate of mtDNA mutation and depletion, two types of genetic instability that cause mtDNA disease in humans. Because of this genetic instability, polg-1D207A worms suffer from an age-related decline in mitochondrial respiration and muscle function, mimicking the pathology seen in human patients. We propose to screen these worms by RNAi to identify genes that can either increase or decrease the severity of mtDNA disease. With this strategy, we have already discovered that IGF-1/insulin signaling, mitochondrial protein quality control, mitochondrial dynamics, mTor signaling, autophagy and apoptosis, all control the severity of mtDNA disease in worms. The strongest modulator of mtDNA disease that we identified thus far, is the IGF-1/insulin signaling pathway. It has long been known that reduced IGF-1/insulin signaling has beneficial effects for the overall health of organisms; however, we have now identified a discrete set of diseases for which reduced IIS activity may have a direct therapeutic application. Since this pathway is well-understood, and numerous drugs and genetic mutants are available for experimentation, we are in a unique position to rapidly transform these initial observations into a comprehensive program that has immediate translational relevance. To initiate this program, we propose to dissect the molecular mechanisms by which reduced IGF-1/insulin signaling rescues worms from mtDNA disease. These experiments will provide deep insight into the etiology of mtDNA disease and demonstrate that the IIS pathway modulates mtDNA disease by numerous mechanisms, at multiple levels of organization. In addition, we will test the therapeutic potential of our findings by investigating whether reduced IIS activity can ameliorate mtDNA disease in mice as well. We anticipate that these experiments will demonstrate that reduced IGF-1/insulin signaling has broad beneficial effects for all forms mtDNA disease, and will thus be a powerful ally in our battle against mitochondrial disorders.

抽象的 线粒体基因组（mtDNA）的遗传不稳定性在人类衰老和疾病中起重要作用。 例如，mtDNA不稳定会导致失明，耳聋，肌病和严重的脑病 儿童，并有助于衰老成年人的肌肉浪费，癌症进展和神经退行性。到 但是，这一天，没有任何孩子因遗传的mtDNA疾病治愈或成功治疗，也没有 对于年龄相关疾病的mtDNA成分存在治疗。成功设计治疗性 策略，确定可以增加或减少的分子机制将很重要 由mtDNA不稳定引起的病理。然后，我们可以用药物操纵这些途径以防止 或延迟这些疾病。确定这些途径需要一个非常适合的灵活动物模型 “发现实验”；因此，我们在线虫C中创建了mtDNA不稳定性的新动物模型。 秀丽隐杆线。使用CRISPR/CAS9技术，我们创建了一个容易发生的DNA聚合酶伽马等位基因（POLG- 1d207a），复制线粒体基因组的酶。携带此等位基因的蠕虫显示高架 mtDNA突变和定义的速率，两种类型的遗传不稳定性引起人类疾病。 由于这种遗传不稳定，POLG-1D207A蠕虫遭受与年龄相关的线粒体下降 呼吸和肌肉功能，模仿人类患者的病理。我们建议筛选这些 RNAi的蠕虫鉴定可以增加或降低mtDNA疾病严重程度的基因。与此 策略，我们已经发现IGF-1/胰岛素信号传导，线粒体蛋白质质量控​​制， 线粒体动力学，MTOR信号传导，自噬和凋亡，所有这些都控制着mtDNA疾病的严重程度 蠕虫。到目前为止，我们确定的MTDNA疾病的强调是IGF-1/胰岛素信号传导 路径。早就知道，减少的IGF-1/胰岛素信号传导对整体具有有益的影响 生物健康；但是，我们现在已经确定了一组离散的疾病，该疾病减少了IIS活动 可能具有直接的治疗应用。由于这条途径是充分理解的，而且许多药物和 基因突变体可用于实验，我们处于独特的位置，可以快速转化这些初始 观察到具有立即翻译相关性的综合计划。启动这一点 程序，我们建议剖析减少IGF-1/胰岛素信号拯救的分子机制 MtDNA疾病的蠕虫。这些实验将为MTDNA疾病的病因提供深入的洞察力 并证明IIS途径通过多种机制调节mtDNA疾病 组织。此外，我们将通过研究是否研究是否研究我们发现的治疗潜力 IIS活性的降低也可以改善小鼠的mtDNA疾病。我们预计这些实验将 证明减少的IGF-1/胰岛素信号传导对所有形式的mtDNA疾病都具有广泛的有益作用，并且 因此，在我们与线粒体疾病的斗争中，将是一个有力的盟友。