PATHOGENIC MECHANISMS /THERAPEUTIC STRATEGIES /CELLULAR MODELS /mtDNA MUTATIONS

致病机制/治疗策略/细胞模型/线粒体DNA突变

• 批准号: 7547770
• 负责人: MERCY MASCREEN DAVIDSON
• 金额: $ 24.91万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7547770
• 关键词: Address; Adrenal Cortex Hormones; Animal Model; Astrocytes; Biological Models; Blood - brain barrier anatomy; Blood Vessels; Brain; Brain Neoplasms; Carrier Proteins; Cell membrane; Cell model; Cells; Cerebral Edema; Cerebral Infarction; Cerebral cortex; Clinical; Coculture Techniques; Collaborations; Collagen; Complement; Complex; Data; Dexamethasone; Disease; Edema; Electrical Resistance; Endothelial Cells; Event; Fibrinogen; Foot Process; Functional disorder; Funding; Genes; Glucocorticoids; Goals; Grant; Hand; Human; Hydrocortisone; In Vitro; Ion Transport; Lactate Transporter; Lactic Acidosis; Leucine-Specific tRNA; Measures; Methods; Mitochondrial DNA; Mitochondrial Diseases; Mitochondrial Encephalomyopathies; Modeling; Mutation; Myoblasts; Neurodegenerative Disorders; Neurons; Outcome; Pathogenesis; Patients; Permeability; Physiological; Point Mutation; Proteins; Reproducibility; Research Personnel; Respiratory Chain; Side; Standards of Weights and Measures; Steroids; Stroke; System; Technology; Testing; Therapeutic; Tight Junctions; Translations; Umbilical vein; Vascular Permeabilities; Water; analog; aquaporin 4; cell type; improved; in vitro Model; insight; mitochondrial dysfunction; mutant; prevent; programs; therapeutic effectiveness; tissue culture; water channel

MELAS is the most common mitochondrial disease associated with a A3243G mutation in the tRNALeu gene of the mtDNA, and characterized by lactic acidosis, strokes, cerebral infarction and edema. The pathogenesis of strokes and edema in MELAS patients is not understood. Without a proper understanding of the pathophysiology, it has not been possible to devise rational therapies. Mitochondrial dysfunction in the cortical blood vessels may perhaps cause a breakdown of the blood-brain barrier (BBB). Using in vitro models of normal and MELAS BBB, we propose to study alterations in permeability functions, expression of tight junctions, water channels and lactate transporters, and correlate the data with respiratory chain function. We have the necessary wild-type and mutant cells, and we have demonstrated that we can construct the normal BBB with tight junctions. Management of stroke in MELAS patients with steroids has been anecdotally effective. Glucocorticoids are effective in treatment of cerebral edema associated with brain tumors. But the mechanism by which they act is not clear. The in vitro BBB system is a dynamic model which can be manipulated to test the effect of steroids in regulating brain water content. We propose to study the effect of hydrocortisone, and its synthetic analog, dexamethasone, on paracellular permeability, using the MELAS BBB model. First, these studies will provide insights into the physiological mechanisms associated with the BBB. Secondly, they will reveal critical information regarding pathological changes in vascular permeability in MELAS due to mitochondrial dysfunction and energy shortage. The culture model will also allow us to evaluate the sequence of events leading to the increase in permeability. Finally, the in vitro model provides a flexible system to test therapeutic effectiveness of steroids in patients with this devastating illness.

MELAS是与mtDNA的tRNALeu基因中的A3243G突变相关的最常见的线粒体疾病，并且以乳酸性酸中毒、中风、脑梗塞和水肿为特征。MELAS患者中风和水肿的发病机制尚不清楚。如果没有对病理生理学的正确理解，就不可能设计出合理的治疗方法。皮质血管中的线粒体功能障碍可能导致血脑屏障（BBB）的破坏。使用正常和MELAS BBB的体外模型，我们建议研究渗透性功能、紧密连接、水通道和乳酸转运蛋白表达的变化，并将数据与呼吸链功能关联起来。我们有必要的野生型和突变型细胞，我们已经证明，我们可以 构建具有紧密连接的正常血脑屏障。使用类固醇治疗MELAS患者的卒中是有效的。糖皮质激素是治疗脑肿瘤相关脑水肿的有效药物。但它们的作用机制尚不清楚。体外血脑屏障系统是一个动态模型，可用于检测类固醇对脑含水量的调节作用。我们建议研究氢化可的松的作用， 合成类似物地塞米松对细胞旁通透性的影响，使用MELAS BBB模型。 首先，这些研究将提供与BBB相关的生理机制的见解。其次，它们将揭示有关MELAS中由于线粒体功能障碍和能量短缺导致的血管通透性病理变化的关键信息。培养模型还将允许我们评估导致渗透性增加的事件的顺序。最后，体外模型提供了一个灵活的系统来测试类固醇对患有这种毁灭性疾病的患者的治疗效果。