Bromodomain Inhibitors Correct Bioenergetic Deficiency Caused by Mitochondrial Disease Complex Mutations

项目摘要 线粒体疾病包括一组异质的遗传性遗传性疾病， 线粒体或核编码基因的突变，导致线粒体能量和 代谢功能，在最严重的情况下，会导致死亡。发病率为1：5000， 报告将线粒体疾病列为最常见的人类遗传疾病之一。到目前为止， 没有有效的治疗方法，因此，代表了开发新的 技术和平台，以发现新的治疗机会。确定具体目标， 增加线粒体生物能量学的药物可以具有治疗线粒体疾病的治疗价值。 为了实现这一目标，我们进行了一个公正的高通量化学和互补的全基因组 CRISPR编辑筛选在线粒体中携带突变的跨线粒体杂交（胞质杂种）细胞 编码复合物I亚单位。IBET 525762A布罗莫结构域和末端外结构域（IBET）抑制剂 出现作为最有效的化合物，以提高氧化磷酸化（OXPHOS）的能力，在这些 细胞IBET 525762 A功能性靶向含溴结构域蛋白4（Brd4），其抑制增强了 氧化磷酸化基因、蛋白质和活性。此外，Brd4抑制促进人胞质杂交细胞 在高能量需求下存活，并保护免受半乳糖诱导的细胞死亡（标准临床试验）。 测定以鉴定线粒体缺陷）。为了探索详细描述Brd4抑制如何控制 在线粒体生物能量学的基础上，将进行一系列全面的生化和代谢分析。 将评估两个具体目标。在第一个目标中，我们想探索一种分子和功能上的 水平Brd4如何控制胞质杂交细胞中的线粒体基因表达程序。我们会绘制出 和Brd4的相互作用伙伴，以深入了解这一机制。目标2将评估细胞，代谢， 和Brd4抑制在其他人胞质杂种和患者来源的成纤维细胞中的生物能量效应， 多种线粒体疾病我们将确定IBET 525762A介导的OXPHOS增加是否 程序可以持续到线粒体疾病的其他细胞模型。拟议研究的结果 将提高我们对Brd4抑制如何恢复线粒体能量功能的理解， 疾病细胞模型。这将导致开发有效的治疗线粒体疾病的患者的方法。 紊乱

Project Abstract Mitochondrial diseases comprise a heterogeneous group of genetically inherited disorders resulting from mutations in mitochondrial or nuclear encoded genes that cause failures in mitochondrial energetic and metabolic function which, in the most severe cases, will lead to death. Incidence rates of 1:5000 have been reported placing mitochondrial disorders as one of the most commonly inherited human diseases. To date, there are no effective treatments, and as such, represents an urgent medical need to develop new technologies and platforms to uncover novel therapeutic opportunities. Identification of specific targets and drugs that increase mitochondrial bioenergetics can be of therapeutic value to treat mitochondrial diseases. To address this goal, we performed an unbiased high-throughput chemical and complementary genome-wide CRISPR editing screen in trans-mitochondrial hybrid (cybrids) cells harboring a mutation in a mitochondrial encoded complex I subunit. The IBET 525762A bromodomain and extraterminal domain (IBET) inhibitor emerged as the most potent compound to enhance the oxidative phosphorylation (OXPHOS) capacity in these cells. IBET 525762A functionally targets bromodomain-containing protein 4 (Brd4) and its inhibition enhances oxidative phosphorylation genes, protein, and activity. Furthermore, Brd4 inhibition promotes human cybrid cell survival under high energetic demands and protects against galactose-induced cell death (a standard clinical assay to identify mitochondrial defects). To explore the mechanism detailing how Brd4 inhibition controls mitochondrial bioenergetics, a series of comprehensive biochemical and metabolic analysis will be performed. Two specific aims will be assessed. In the first aim, we would like to explore on a molecular and functional level how Brd4 controls mitochondrial gene expression programs in cybrid cells. We will map the occupancy and interacting partners of Brd4 to gain insights into this mechanism. Aim 2 will assess the cellular, metabolic, and bioenergetic effects of Brd4 inhibition in other human cybrid and patient-derived fibroblasts cells with diverse mitochondrial disorders. We will determine if IBET 525762A-mediated increases in the OXPHOS program can persist to other cellular models of mitochondrial disease. The results from the proposed studies will improve our understanding of how Brd4 inhibition restores mitochondrial energetic function in mitochondrial disease cellular models. This will lead to the development of effective therapies for patients with mitochondrial disorders.