Aging-related mitochondrial degeneration and degenerative diseases

与衰老相关的线粒体变性和退行性疾病

• 批准号: 8068349
• 负责人: Xin Jie Chen
• 金额: $ 31.38万
• 依托单位: UPSTATE MEDICAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8068349
• 关键词: ATP Synthesis Pathway; Adenine Nucleotide Translocase; Adult; Affect; Aging; Anabolism; Biochemical; Bioenergetics; Biogenesis; Biological; Biological Assay; Cell Aging; Cell Death; Cell Survival; Cell physiology; Cells; Chronic progressive external ophthalmoplegia; Complex; Coupling; Cytosol; Defect; Defense Mechanisms; Degenerative Disorder; Electron Transport; Event; Gene Expression; Genes; Genetic; Genetic Screening; Genetic Transcription; Goals; Grant; Homeostasis; Human; Inner mitochondrial membrane; Intervention; Laboratories; Lead; Link; Longevity; Maintenance; Measures; Mediating; Membrane; Membrane Potentials; Mitochondria; Molecular; Mutate; Mutation; Organelles; Orthologous Gene; Pathway interactions; Phenotype; Phospholipids; Process; Protein Biosynthesis; Proteins; Quality Control; Stress; Symptoms; System; Testing; Translations; Yeast Model System; Yeasts; age related; base; cell age; fitness; gain of function mutation; improved; innovation; insight; mRNA Decay; membrane biogenesis; mitochondrial dysfunction; mitochondrial membrane; multicatalytic endopeptidase complex; mutant; neuromuscular; novel; oxidative damage; prohibitin; protein aggregation; protein degradation; public health relevance; research study; respiratory; tool; trait; yeast genetics

DESCRIPTION (provided by applicant): Mitochondrial function degenerates with aging. The overall goals of our proposal are (1) to better understand how aging induces mitochondrial degeneration and (2) to identify cellular pathways other than the currently known anti-oxidative mechanisms that can potentially delay the degenerative process. In the previous grant period, we developed a yeast model for the adult/late-onset neuromuscular degenerative disease autosomal dominant Progressive External Ophthalmoplegia (adPEO), caused by gain-of-function mutations in the adenine nucleotide translocase (Ant). Ant is normally involved in ADP/ATP exchange across the mitochondrial inner membrane. We found that equivalent mutations in yeast induce aging-dependent mitochondrial depolarization and -aging prohibitin mutants. These unique experimental systems enabled us to unequivocally demonstrate that reducing cytosolic protein synthesis can robustly suppress aging-dependent mitochondrial degeneration. This finding reveals an unanticipated link between cellular protein homeostasis (or proteostasis) and the functional integrity of mitochondria. In a recent genetic screen for anti-degenerative suppressors, we identified genes involved in cytosolic mRNA decay and protein degradation. Several of these proteostatic genes/pathways have human orthologs known to be mutated in degenerative diseases. These observations led to our central hypothesis that loss of protein homeostasis in the cytosol may induce proteostatic stress on the mitochondrial inner membrane, which consequently affects energy homeostasis and the fitness of aged cells. To test this, we propose the following aims: (1) We will examine the link between cellular proteostasis and mitochondrial integrity during replicative aging. We will specifically determine whether defects in mRNA decay and protein degradation, which cause protein phenotypically tractable degenerative cell death. These phenotypes were also independently captured in the pro overloading from the cytosol, can generally accelerate aging-dependent mitochondrial degeneration; (2) We will test the hypothesis that cytosolic proteostatic stress may affect protein homeostasis, respiratory complex biogenesis, bioenergetic efficiency and structural integrity of the mitochondrial inner membrane; and (3) By taking advantage of the anti-degenerative genes identified in our study, we will examine whether over-expression of these genes, which improves mitochondrial membrane integrity and energy transduction, extends cell's lifespan. Because decline of cellular proteostasis is a common molecular symptom of aging and some degenerative diseases, our studies may help us better understand the mechanism of mitochondrial degeneration under these conditions. PUBLIC HEALTH RELEVANCE: The mitochondrion is known as the powerhouse of the cell and its function degenerates with aging and in aging-related degenerative disorders. We aim to identify evolutionarily conserved cellular pathways that can delay the aging-dependent degeneration of mitochondria and improve energy homeostasis in aged cells. These "anti-degenerative" pathways may be potentially used as intervention targets for delaying the onset and progression of mitochondrial degeneration.

描述（由申请人提供）：线粒体功能随着衰老而退化。我们提案的总体目标是（1）更好地了解衰老如何诱导线粒体变性；（2）识别除目前已知的抗氧化机制之外的可能延迟变性过程的细胞途径。在上一个资助期间，我们开发了一种酵母模型，用于治疗成人/迟发性神经肌肉退行性疾病常染色体显性进行性外眼肌麻痹（adPEO），该疾病是由腺嘌呤核苷酸易位酶（Ant）的功能获得性突变引起的。 Ant 通常参与线粒体内膜的 ADP/ATP 交换。我们发现酵母中的等效突变会诱导衰老依赖性线粒体去极化和衰老抑制蛋白突变体。这些独特的实验系统使我们能够明确证明减少胞浆蛋白合成可以强有力地抑制衰老依赖性线粒体变性。这一发现揭示了细胞蛋白质稳态（或蛋白质稳态）与线粒体功能完整性之间的意想不到的联系。在最近的抗退行性抑制基因筛选中，我们鉴定了参与胞质 mRNA 降解和蛋白质降解的基因。这些蛋白质抑制基因/途径中的一些具有已知在退行性疾病中发生突变的人类直向同源物。这些观察结果得出我们的中心假设，即细胞质中蛋白质稳态的丧失可能会引起线粒体内膜的蛋白质稳态应激，从而影响能量稳态和衰老细胞的健康。为了测试这一点，我们提出以下目标：（1）我们将检查复制衰老过程中细胞蛋白质稳态和线粒体完整性之间的联系。我们将具体确定 mRNA 衰变和蛋白质降解是否存在缺陷，从而导致蛋白质表型上易于处理的退行性细胞死亡。这些表型也被独立地捕获在胞质溶胶中的亲超载中，通常可以加速衰老依赖性线粒体变性； （2）我们将检验细胞质蛋白稳态应激可能影响蛋白质稳态、呼吸复合物生物合成、生物能效率和线粒体内膜结构完整性的假设； (3)通过利用我们研究中发现的抗退行性基因，我们将检查这些基因的过度表达是否可以改善线粒体膜的完整性和能量转导，从而延长细胞的寿命。由于细胞蛋白质稳态下降是衰老和一些退行性疾病的常见分子症状，因此我们的研究可能有助于我们更好地了解这些条件下线粒体变性的机制。 公共健康相关性：线粒体被称为细胞的动力源，其功能会随着衰老和与衰老相关的退行性疾病而退化。我们的目标是确定进化上保守的细胞途径，可以延缓线粒体的衰老依赖性退化并改善衰老细胞的能量稳态。这些“抗退行性”途径可能有可能用作延迟线粒体退行性变的发生和进展的干预目标。