Adaptation to long chain fatty acid oxidation deficiency

适应长链脂肪酸氧化缺陷

• 批准号: 6710988
• 负责人: ARNOLD W STRAUSS
• 金额: $ 36.68万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2008-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6710988
• 关键词: acyl coA dehydrogenases; arrhythmia; bioenergetics; calcium metabolism; carcinogenesis; clinical research; electrophysiology; electrospray ionization mass spectrometry; enzyme deficiency; gene mutation; genetic polymorphism; genetically modified animals; genotype; heart disorder; heart function; human genetic material tag; human subject; immunocytochemistry; laboratory mouse; microarray technology; obesity; oxidative stress; phenotype; sudden cardiac death; telemetry

DESCRIPTION (provided by applicant): Very-long-chain acyI-CoA dehydrogenase (VLCAD) catalyzes the first step of the mammalian mitochondrial fatty acid oxidation (FAO) spiral that generates energy in the heart and other highly oxidative tissues. Human recessive VLCAD deficiency produces phenotypes of early fatal cardiomyopathy and arrhythmias, infantile hypoketotic hypoglycemia and liver failure, sudden death in infancy (SIDS), and later episodic skeletal myopathy. Our first hypothesis is that VLCAD deficiency has a genotype-phenotype correlation that we will investigate (Aim 1) through molecular genetics, correlating with clinical phenotypes, and by studying the pathogenetics of some VLCAD mutations, particularly V243A that exists in patients discovered by newborn screening. Our second hypothesis is that VLCAD is essential for cardiac function both because of its enzymatic role, but also because VLCAD is required for transcriptional regulation of multiple genes. This will be investigated by characterizing the 20 bp long VLCAD enhancer we have isolated (Aim 2) and by characterizing VLCAD-deficient mice and their heterozygote littermates that exhibit the phenotypes of sudden death, late-onset obesity, development of tumors, and inducible arrhythmias and that die in response to fasting and exposure to cold. This characterization includes use of transgenic mice and cell transfections to examine VLCAD transcriptional regulation (Aim 2) and telemetry, invasive electrophysiology, microarray analysis, exercise testing, and dietary manipulation of VLCAD -/- and +/- animals (Aim 3). We will also create tissue-specific (heart, brown fat, liver, muscle) knockouts (Aim 4) to ascertain the relative contributions of these organs to phenotypes. We know that VLCAD -/- animals exhibit marked alterations in tissue gene expression by one day, a perinatal "adaptive response". We hypothesize that this live-saving adaptive response creates differences in gene expression that are the substrate for the later pathologies of sudden death, arrhythmias, obesity, and tumorigenesis. This is, thus, a model of how polymorphisms or mutations in one gene modify expression of other later in life, leading to pathology. One highly induced gene in this genetic response is a novel protein, designated heart endothelin-related substance (HERS) that, based upon homology and expression data, we postulate functions in cardiac development and calcium metabolism. We will investigate its role by generating a HERS knockout in the last specific aim.

描述（由申请人提供）：极长链酰基辅酶A脱氢酶（VLCAD）催化哺乳动物线粒体脂肪酸氧化（FAO）螺旋的第一步，在心脏和其他高度氧化组织中产生能量。人类隐性VLCAD缺陷产生早期致命性心肌病和心律失常、婴儿低酮性低血糖和肝衰竭、婴儿猝死（SIDS）和后来的发作性骨骼肌病的表型。我们的第一个假设是，VLCAD缺陷具有基因型-表型相关性，我们将通过分子遗传学研究（目的1），与临床表型相关，并通过研究一些VLCAD突变的发病机制，特别是新生儿筛查发现的患者中存在的V243 A。我们的第二个假设是，VLCAD是心脏功能必不可少的，因为它的酶的作用，但也因为VLCAD是需要多个基因的转录调控。这将通过表征我们已经分离的20 bp长的VLCAD增强子（目的2）和通过表征VLCAD缺陷小鼠及其杂合子同窝仔来研究，所述杂合子同窝仔表现出猝死、迟发性肥胖、肿瘤发展和诱导性心律失常的表型，并且响应于禁食和暴露于寒冷而死亡。该表征包括使用转基因小鼠和细胞转染来检查VLCAD转录调节（目的2）和遥测、侵入性电生理学、微阵列分析、运动测试以及VLCAD -/-和+/-动物的饮食操作（目的3）。我们还将创建组织特异性（心脏，棕色脂肪，肝脏，肌肉）敲除（目的4），以确定这些器官对表型的相对贡献。我们知道VLCAD -/-动物在一天内表现出组织基因表达的显著改变，这是围产期的“适应性反应”。我们假设，这种挽救生命的适应性反应造成了基因表达的差异，这些差异是后来猝死、心律失常、肥胖和肿瘤发生等病理学的基础。因此，这是一个模型，说明一个基因的多态性或突变如何在以后的生活中改变另一个基因的表达，从而导致病理学。一个高度诱导的基因在这种遗传反应是一种新的蛋白质，指定心脏内皮素相关物质（HERS），基于同源性和表达数据，我们假设在心脏发育和钙代谢的功能。我们将通过在最后一个特定目标中产生HERS敲除来研究其作用。