Inborn Errors of Long Chain Fat Metabolism

长链脂肪代谢先天性错误

• 批准号: 7816624
• 负责人: GERARD VOCKLEY
• 金额: $ 29.39万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7816624
• 关键词: Acute Liver Failure; Acyl CoA Dehydrogenases; Acyl Coenzyme A; Affect; Alternative Splicing; Amino Acid Motifs; Amino Acids; Bile Acid Biosynthesis Pathway; Bile Acids; Biogenesis; Cardiomyopathies; Catabolism; Cell Nucleus; Cells; Cessation of life; Chemicals; Chenodeoxycholic Acid; Clinical; Complex; Data; Defect; Development; Disease; Enzymes; Equilibrium; Esters; Family; Fatty Acids; Fatty Liver; Gene Family; Generations; Genes; Genetic; Genotype; Goals; Hereditary Disease; Human; Inborn Errors of Metabolism; Inborn Genetic Diseases; Inner mitochondrial membrane; Knockout Mice; Lead; Learning; Lecithin; Length; Lipids; Liver Failure; Location; Long-Chain-Acyl-CoA Dehydrogenase; Lung; Metabolic; Metabolic Pathway; Metabolism; Mitochondria; Mitochondrial Matrix; Molecular; Molecular Conformation; Mus; Mutation; Newborn Infant; Pathway interactions; Patients; Pattern; Phenotype; Physiological; Premature Infant; Preparation; Process; Proteins; Reye Syndrome; Role; Structure-Activity Relationship; Substrate Specificity; Tissues; Variant; acyl-CoA dehydrogenase; base; dehydrogenation; enzyme deficiency; fatty acid oxidation; in vivo; lipid metabolism; member; mouse model; mutant; novel; oxidation; surfactant

DESCRIPTION (provided by applicant): The acyl-CoA dehydrogenases (ACDs) are a family of multimeric flavoenzymes that catalyze the 1,2- dehydrogenation of acyl-CoA esters in fatty acid 2-oxidation and amino acid catabolism. Inborn errors of metabolism have been identified in seven of the ACDs. The long range objective of this project has been to investigate important structure/function relationships in the ACD gene family. We have described and characterized several new members of the ACD gene family. Among these are 3 enzymes with significant activities with long chain substrates: long and very long chain acyl-CoA dehydrogenases (LCAD and VLCAD, respectively), and ACD9 and. Our prior and preliminary studies show that these enzymes have distinct substrate utilization profiles, tissue and developmental expression patterns, exist in multiple active forms in the cell, and are present in multiple subcellular locations. The goal of this revised application is to characterize the physiologic roles of LCAD, VLCAD, and ACD9 and explore the ramifications of genetic deficiencies of these enzymes in humans and mouse models. Specific Aim 1 is to characterize variant forms of very long chain acyl-CoA dehydrogenase (VLCAD) and the molecular basis of clinical variability in this disorder. Specific aim 1a is to identify the amino acid motif(s) important in determining the unique localization of VLCAD to the inner mitochondrial membrane. Specific aim 1b is to characterize alternative forms of VLCAD identified in vivo. We have identified 3 variant forms of this enzyme in vivo that are generated through alternative splicing. I hypothesize that each has a different substrate specificity that provides functional optimization for progressively shorter substrate species. Specific aim 1c is to characterize the effect of patient mutations in VLCAD on enzyme function. Specific Aim 2 is to more completely characterize ACD9 and its deficiency in humans. Specific Aim 2a is identification of additional patients with ACD9 deficiency and definition of its clinical spectrum. Specific Aim 2b is characterization of the subcellular distribution of ACD9 and the function and molecular configuration of ACD9 protein outside of mitochondria. I hypothesize that this alternative form of ACD9 has non-enzymatic "moonlighting" functions in the cell. Specific Aim 3 is to elucidate the physiologic function of LCAD. Despite its early recognition, its in vivo metabolic role remains a mystery. Our preliminary data implicates it in bile acid and surfactant metabolism. Specific Aim 3a is to characterize the role of LCAD in bile acid synthesis. I hypothesize that it characterizes a key intermediate step in chenodeoxycholic acid synthesis in a mitochondrial based acidic pathway that is involved in the control of cellular metabolic rate. Specific Aim 3b is to explore the role of LCAD in surfactant metabolism using an LCAD null mouse. These studies necessitate a fundamental revision in our view of mitochondrial 2-oxidation from a metabolic pathway that is only responsible for energy generation to one that is active as well in a variety of previously unrec- ognized functions in other important biologic processes.The acyl-CoA dehydrogenases are important enzymes in maintaining normal chemical balance in the body. We have identified a new genetic disorder of one of these enzymes that leads to liver failure. Studying this disorder is important to learn more about its clinical presentation and treatment.

描述（由申请人提供）： 酰基辅酶A脱氢酶（acyl-coA dish ases，ACD）是一类多聚体黄素酶，它催化辅酶A的1，2-脱氢， 酰基coa 酯 脂肪 酸2-氧化和 氨基 酸性催化剂 先天性代谢缺陷 在7个ACD中发现了代谢异常。 该项目的长期目标是研究ACD基因家族中重要的结构/功能关系。 我们已经描述并表征了ACD基因家族的几个新成员。 其中有3种酶活性显著 用长链底物：长 和极长链酰基-CoA脱氢酶（分别为LCAD和VLCAD），以及ACD 9和. 我们先前和初步的研究表明，这些酶具有不同的底物利用谱，组织和发育表达模式，在细胞中以多种活性形式存在，并存在于多个亚细胞位置。 该修订申请的目标是表征LCAD、VLCAD和ACD 9的生理作用，并探索这些酶在人类和小鼠模型中遗传缺陷的后果。 具体目的1是表征极长链酰基辅酶A脱氢酶（VLCAD）的变体形式和该变体中临床变异的分子基础。 disorder. 具体目标1a是鉴定在决定VLCAD至线粒体内膜的独特定位中重要的氨基酸基序。 具体目标1b是描述替代形式的特征 的VLCAD在体内鉴定。 我们已经在体内鉴定了这种酶的3种变体形式，它们通过选择性剪接产生。 我假设，每一种都有不同的底物特异性，为逐渐缩短的底物种类提供功能优化。 具体目标1c是表征VLCAD患者突变对酶功能的影响。 具体目标2是更全面地表征人类中的ACD 9及其缺陷。 具体目标2a是识别其他ACD 9缺陷患者并定义其临床谱。 具体目标2b是表征ACD 9的亚细胞分布以及线粒体外ACD 9蛋白的功能和分子构型。 我假设这种替代形式的ACD 9在细胞中具有非酶的“兼职”功能。 具体目标3是阐明LCAD的生理功能。 尽管它的早期认识，其在体内代谢的作用仍然是一个谜。 我们的初步数据表明它与胆汁酸和表面活性剂代谢有关。 具体目的3a是表征LCAD在胆汁酸合成中的作用。 我推测，它的特点是一个关键的中间步骤，鹅去氧胆酸合成的线粒体为基础的酸性途径，参与控制细胞的代谢率。具体目标3b是使用LCAD敲除小鼠探索LCAD在表面活性剂代谢中的作用。 这些研究需要对线粒体2-氧化的观点进行根本性的修正，从仅负责能量产生的代谢途径转变为在各种先前未被认识的功能中也具有活性的代谢途径 在 其他重要 生物 processes.The 酰基coa 脱氢酶 是 重要 酶 在 保持 正常 化学 平衡 在 的 身体我们已经确定了一种新的遗传疾病的这些酶之一，导致肝功能衰竭。 研究这种疾病对于更多地了解其临床表现和治疗非常重要。