Molecular Basis of a New Form of Hyperinsulinism

新型高胰岛素血症的分子基础

基本信息

批准号：
7992519
负责人：
CHARLES ALFRED STANLEY
金额：
$ 4.86万
依托单位：
CHILDREN'S HOSP OF PHILADELPHIA
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：
2010-01-01 至 2010-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7992519
关键词：
Acyl CoA Dehydrogenases Acyl Coenzyme A Affect Amino Acids B-Lymphocytes Calcium Carbon Carnitine Cell membrane Cells Child Choline Data Defect Diet Disease Enzymes Esters Fasting Fatty Acids Fatty acid glycerol esters Fluorescence Microscopy Funding Genetic Glucose Glutamate Dehydrogenase Glutamine Glyburide Goals Grant Hepatic Hormones Human Hyperammonemia Hyperinsulinism Hypoglycemia In Vitro Incubated Insulin Investigation Kinetics Knock-out Knockout Mice Length Leucine Liver Mass Spectrum Analysis Measures Mediating Membrane Mitochondria Mitochondrial Diseases Modeling Molecular Mus Mutation Nature Nonesterified Fatty Acids Nutrient Oxygen Consumption Palmitates Pancreas Pathway interactions Persistent Hyperinsulinemia Hypoglycemia of Infancy Play Potassium Channel Ramp Research Personnel Role Site Stimulus Syndrome Testing acyl-CoA dehydrogenase analog base blood glucose regulation diabetic enzyme deficiency fasting glucose fatty acid oxidation gain of function mutation glucagon-like peptide 1 hypoglycin A in vivo inhibitor/antagonist insight insulin secretion islet long chain fatty acid loss of function mutation mouse model novel oxidation programs research study response

项目摘要

DESCRIPTION (provided by applicant): This is a request for 5 years of renewed funding to study the molecular basis of novel genetic forms of congenital hyperinsulinism (HI) in children. Previous years focused on the mechanisms of the hyperinsulinism / hyperammonemia syndrome associated with dominant, gain of function mutations of glutamate dehydrogenase (GDH). The goal of this proposal is to determine the mechanisms of HI caused by recessive, loss of function mutations of the mitochondrial fatty acid ¿-oxidation enzyme, short-chain 3-hydroxy acyl-CoA dehydrogenase (SCHAD). Our hypotheses are (1) that the dysregulation of insulin secretion in SCHAD deficiency is caused by an accumulation of a specific fatty acid metabolite(s); and (2) that, unlike other HI disorders which act on the KATP "triggering" pathway of insulin release via plasma membrane depolarization, SCHAD deficiency acts on an "amplification" site(s) downstream of the "triggering" mechanism. These hypotheses will be examined using a mouse SCHAD-/- knockout model. Aim 1 will determine the responses of SCHAD-/- mice to fasting and glucose loading in vivo and whether these responses are altered by a high fat diet. Aim 2 will define the abnormalities in insulin responses to nutrient and glyburide stimulation in the presence and absence of short, medium, and long-chain fatty acids using perifused isolated islets from SCHAD-/- mice and other HI mouse models. Inhibitors of other steps in mitochondrial fatty acid oxidation will be used to test whether effects are specific to SCHAD substrates. Aim 3 will determine the profiles of fatty acid metabolites in isolated SCHAD-/- islets using mass spectrometry to measure acyl-CoAs, acyl-carnitines, and free fatty acids. Aim 4 will determine the effects of SCHAD deficiency on islet cytosolic calcium and mitochondrial energy responses to nutrient stimuli in the presence and absence of fatty acids. Fatty acids are considered to play important roles in regulating insulin secretion by pancreatic ¿-cells, however, their mechanisms of action are poorly understood. SCHAD deficiency provides a unique "experiment of nature" for elucidating not only how fatty acids disturb insulin secretion in children affected with this disorder, but also how these important nutrients contribute to the control of insulin secretion in normal and diabetic humans.

描述（由申请人提供）：这是一项为期 5 年的更新资助申请，用于研究儿童先天性高胰岛素血症 (HI) 的新型遗传形式的分子基础，前几年的重点是与显性遗传相关的高胰岛素血症/高氨血症综合征的机制。谷氨酸脱氢酶 (GDH) 的功能获得突变该提案的目标是确定由线粒体脂肪酸隐性、功能丧失突变引起的 HI 机制。 ¿ -氧化酶，短链 3-羟基酰基辅酶 A 脱氢酶 (SCHAD) 我们的假设是 (1) SCHAD 缺乏症中胰岛素分泌失调是由特定脂肪酸代谢物的积累引起的； 2) 与其他通过质膜去极化作用于 KATP“触发”胰岛素释放途径的 HI 疾病不同，SCHAD 缺陷作用于下游的“放大”位点这些假设将使用小鼠 SCHAD-/- 敲除模型进行检验，目的 1 将确定 SCHAD-/- 小鼠对体内禁食和葡萄糖负荷的反应，以及这些反应是否会因高血糖而改变。目标 2 将使用来自 SCHAD-/- 小鼠和其他小鼠的灌注分离胰岛来定义在存在和不存在短链、中链和长链脂肪酸的情况下胰岛素对营养物和格列本脲刺激的异常反应。 HI 小鼠模型将使用线粒体脂肪酸氧化中其他步骤的抑制剂来测试效果是否对 SCHAD 底物具有特异性，目标 3 将使用质谱法测量酰基来确定分离的 SCHAD-/- 胰岛中的脂肪酸代谢物的概况。 CoAs、酰基肉碱和游离脂肪酸将确定 SCHAD 缺乏对胰岛细胞质钙和线粒体能量对营养刺激的反应的影响。脂肪酸的存在和缺乏被认为在调节胰腺的胰岛素分泌中发挥着重要作用。然而，人们对 SCHAD 缺乏症的作用机制知之甚少，这提供了一种独特的“自然实验”，不仅可以阐明脂肪酸如何干扰患有这种疾病的儿童的胰岛素分泌，还可以阐明这些重要的营养素如何有助于控制这种疾病。正常人和糖尿病人的胰岛素分泌。