Investigating the pathogenesis of CoQ10 deficiencies

研究 CoQ10 缺乏症的发病机制

基本信息

批准号：
8141204
负责人：
Catarina M. Quinzii
金额：
$ 8.33万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-09-15 至 2015-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8141204
关键词：
ATP Synthesis Pathway Accounting Affect Aftercare Anabolism Animals Antioxidants Apoptosis Ascorbic Acid Benzoquinones Biochemical Bioenergetics Biological Blood Candidate Disease Gene Cell Death Cell membrane Cells Cerebellar Ataxia Clinical Coenzyme Q10 Commit Complex DNA Data Defect Diagnosis Disease Electron Transport Complex III Electrons Enzymes Family Fibroblasts Gene Mutation Genes Genetic Genetic Counseling Growth Hereditary Disease Heterogeneity Human Individual Inherited Knowledge Lipid Peroxidation Lipids Manganese Superoxide Dismutase Maps Membrane Mentors Mitochondria Mitochondrial Diseases Molecular Molecular Genetics Multienzyme Complexes Muscle Mutation NADH dehydrogenase (ubiquinone)Natural regeneration Nuclear Oral Oxidative Phosphorylation Oxidative Stress Pathogenesis Pathogenicity Pathway interactions Patients Pharmaceutical Preparations Prenatal Diagnosis Production Proteins RNA Interference Radiolabeled Reactive Oxygen Species Regulation Relative (related person)Reporting Residual state Respiratory Chain Role Sampling Severities Shapes Siblings Side Single Strand Break Repair Skin Supplementation Syndrome Tail Testing Therapeutic Transferase Ubiquinone autosomal recessive trait base clinical phenotype cytochrome c decaprenyl pyrophosphate synthetase gene complementation human disease hydroxybenzoate improved infancy isoprenoid mutant novel overexpression oxidation prevent radiotracer response vector

项目摘要

DESCRIPTION (Provided by Applicant): Coenzyme Q10 (CoQ10) is a small lipophilic molecule composed of a benzoquinone ring and a hydrophobic isoprenoid tail which is present in virtually all cell membranes. In the mitochondrial respiratory chain, CoQ10 is vital for the transport of electrons from complex I and complex II to complex III. It is also an antioxidant, membrane stabilizer, and modulator of apoptosis. Human CoQ10-deficiency has been associated with four clinical phenotypes. Patients with all forms of CoQ10-deficiency have improved with oral supplementation, therefore recognition of this treatable genetic condition is important. In the last decade, the candidate and her mentors have collected biological samples from 84 patients (71 families) with documented CoQ10 deficiency in muscle and/or fibroblasts, or suspected CoQ10 deficiency based on the clinical manifestations as well as the response to CoQ10 supplementation. A total of 54 patients (48 families) have documented CoQ10 deficiency in muscle, fibroblasts, or both. In 2006, the investigative team reported the first mutations in CoQ10 biosynthetic genes, COQ2, which encodes 4-para-hydroxybenzoate: polyprenyl transferase; and PDSS2, which encodes subunit 2 of decaprenyl diphosphate synthase. In addition, in a family with four individuals with cerebellar ataxia and CoQ10 deficiency, they identified a pathogenic mutation in the APTX gene, which encodes a protein involved in single-strand break repair. Thus, these studies have revealed that CoQ10 deficiency can be primary or secondary. Not surprisingly, CoQ10 deficiency causes defects of respiratory chain activities (reduced activities of complexes I+III and II+III). The relative importance of respiratory chain defects, ROS production, and apoptosis in the pathogenesis of CoQ10-deficiency is unknown. The investigative team studied the consequences of severe CoQ10 deficiency on bioenergetics, oxidative stress, and antioxidant defenses in cultured skin fibroblasts harboring COQ2 and PDSS2 mutations. Defects in the first two committed steps of the CoQ10 biosynthetic pathway produce different biochemical alterations. PDSS2 mutant fibroblasts have 12% CoQ10 relative to control cells and markedly reduced ATP synthesis, but do not show increased reactive oxygen species (ROS) production, signs of oxidative stress, or increased antioxidant defense markers. In contrast, COQ2 mutant fibroblasts have 30% CoQ10 with partial defect in ATP synthesis, and significantly increased ROS production and oxidation of lipids and proteins. To better understand the pathogenesis of CoQ10 deficiency, the investigative team has characterized the effects of varying severity of CoQ10 deficiency on ROS production and mitochondrial bioenergetics in cells harboring different genetic defects of CoQ10 biosynthesis. They confirmed their previous findings and further observed that the correlation between level of CoQ10 and ROS production follows a parabolic curve; 10-15% residual CoQ10 and 60-70% are not associated with significant ROS production, whereas 30-50% residual CoQ10 is associated with the maximum increases in ROS production. Moreover, increase in reactive oxygen species appears to be associated with initial hyperpolarization followed by depolarization and cell death. These data are corroborated by preliminary results of treatment with CoQ10 and other antioxidants in fibroblasts from the CoQ10 deficient patients. To better understand the pathogenesis of human CoQ10 deficiency the candidate proposes the following three specific aims: Aim 1: To identify novel genetic causes of CoQ10 deficiency. Aim 2: To understand the mitochondrial bioenergetics and oxidative stress consequences of different degrees of CoQ10 deficiency in the same genetic background, she will modulate COQ2 and PDSS2 expression using RNA interference (RNAi). Aim 3: To test ROS scavenging as a potential therapeutic strategy, she will overexpress the enzyme superoxide manganese dismutase (MnSOD) in COQ2 mutant fibroblasts and will assess level of ROS, oxidative stress, and apoptosis. NARRATIVE: Defects of mitochondria cause diverse human diseases. A subtype of mitochondrial disease is caused by deficiency of coenzyme Q10 (CoQ10), an essential component of the mitochondria involved in energy production. Patients with CoQ10 deficiency often improve dramatically with CoQ10 supplementation. The candidate will study patients with this disease and she will attempt to understand why the mutations cause CoQ10 deficiency. Knowing the cause of CoQ10 deficiency will likely enhance our scientific knowledge of CoQ10 biosynthesis, and will provide molecular tests for accurate genetic counseling, prenatal diagnosis, and more rapid initiation of the therapy.

描述（由申请人提供）：辅酶Q10（CoQ10）是一种小亲脂性分子，由苯醌环和疏水性类异戊二烯尾组成，几乎存在于所有细胞膜中。在线粒体呼吸链中，CoQ10 对于电子从复合物 I 和复合物 II 到复合物 III 的传输至关重要。它也是一种抗氧化剂、膜稳定剂和细胞凋亡调节剂。人类 CoQ10 缺乏症与四种临床表型相关。患有各种形式的 CoQ10 缺乏症的患者通过口服补充剂都得到了改善，因此认识到这种可治疗的遗传性疾病非常重要。在过去的十年中，候选人和她的导师从 84 名患者（71 个家庭）中收集了生物样本，这些患者的肌肉和/或成纤维细胞中存在 CoQ10 缺乏症，或根据临床表现以及对补充 CoQ10 的反应怀疑患有 CoQ10 缺乏症。共有 54 名患者（48 个家庭）记录了肌肉、成纤维细胞或两者均缺乏辅酶 Q10。 2006年，研究小组报告了CoQ10生物合成基因COQ2的首次突变，该基因编码4-对羟基苯甲酸酯：聚异戊二烯基转移酶； PDSS2，编码十异戊二烯二磷酸合酶的亚基 2。此外，在一个有四名患有小脑共济失调和 CoQ10 缺乏症的家庭中，他们发现了 APTX 基因的致病性突变，该基因编码一种参与单链断裂修复的蛋白质。因此，这些研究表明 CoQ10 缺乏可能是原发性的，也可能是继发性的。毫不奇怪，CoQ10 缺乏会导致呼吸链活性缺陷（复合物 I+III 和 II+III 的活性降低）。呼吸链缺陷、ROS 产生和细胞凋亡在辅酶 Q10 缺乏的发病机制中的相对重要性尚不清楚。研究小组研究了严重辅酶 Q10 缺乏对含有 COQ2 和 PDSS2 突变的培养皮肤成纤维细胞的生物能、氧化应激和抗氧化防御的影响。 CoQ10 生物合成途径前两个关键步骤的缺陷会产生不同的生化改变。相对于对照细胞，PDSS2 突变型成纤维细胞具有 12% 的 CoQ10，并且 ATP 合成显着减少，但没有表现出活性氧 (ROS) 产生增加、氧化应激迹象或抗氧化防御标记增加。相比之下，COQ2突变的成纤维细胞含有30%的CoQ10，ATP合成部分缺陷，并且ROS的产生以及脂质和蛋白质的氧化显着增加。为了更好地了解 CoQ10 缺乏症的发病机制，研究小组描述了不同严重程度的 CoQ10 缺乏症对具有不同 CoQ10 生物合成遗传缺陷的细胞中 ROS 产生和线粒体生物能的影响。他们证实了之前的发现，并进一步观察到 CoQ10 水平与 ROS 产生之间的相关性遵循抛物线曲线； 10-15% 残留 CoQ10 和 60-70% 与 ROS 产生显着无关，而 30-50% 残留 CoQ10 与 ROS 产生最大增加相关。此外，活性氧的增加似乎与最初的超极化、随后的去极化和细胞死亡有关。使用 CoQ10 和其他抗氧化剂对 CoQ10 缺乏患者的成纤维细胞进行治疗的初步结果证实了这些数据。为了更好地了解人类 CoQ10 缺乏症的发病机制，候选人提出了以下三个具体目标：目标 1：确定 CoQ10 缺乏症的新遗传原因。目标 2：为了了解相同遗传背景下不同程度 CoQ10 缺乏的线粒体生物能学和氧化应激后果，她将使用 RNA 干扰 (RNAi) 调节 COQ2 和 PDSS2 的表达。目标 3：为了测试 ROS 清除作为一种潜在的治疗策略，她将在 COQ2 突变型成纤维细胞中过度表达超氧化锰歧化酶 (MnSOD)，并评估 ROS、氧化应激和细胞凋亡的水平。叙述：线粒体缺陷会导致多种人类疾病。线粒体疾病的一种亚型是由辅酶 Q10 (CoQ10) 缺乏引起的，辅酶 Q10 是参与能量产生的线粒体的重要组成部分。辅酶 Q10 缺乏症患者在补充辅酶 Q10 后通常会得到显着改善。候选人将研究患有这种疾病的患者，并尝试了解为什么突变会导致 CoQ10 缺乏。了解 CoQ10 缺乏的原因可能会增强我们对 CoQ10 生物合成的科学知识，并将为准确的遗传咨询、产前诊断和更快速地开始治疗提供分子测试。