Mechanisms of Lipid-Induced Hepatic Insulin Resistance

脂质诱导的肝胰岛素抵抗的机制

基本信息

批准号：
8816079
负责人：
GERALD I SHULMAN
金额：
$ 34.13万
依托单位：
YALE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1988
资助国家：
美国
起止时间：
1988-12-01 至 2018-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8816079
关键词：
1,2-diacylglycerol ATP Synthesis Pathway Adult Affect American Animal Experiments Animals Antisense Oligonucleotides Caenorhabditis elegans Caloric Restriction Collaborations Coupled Coupling Data Development Diglycerides Energy Metabolism Exhibits Fatty acid glycerol esters Funding Grant Hepatic Hepatocyte Human Impairment In Vitro Inflammation Insulin Insulin Receptor Insulin Resistance Knockout Mice Lead Lipids Liver Liver diseases Longevity Mammals Measures Messenger RNA Methods Mitochondria Molecular Non-Insulin-Dependent Diabetes Mellitus Phosphorylation Phosphoserine Phosphothreonine Phosphotransferases Positioning Attribute Protein Isoforms Protein Kinase Protein Kinase C Protein-Serine-Threonine Kinases Proteins Publications Pyruvate Rattus Reactive Oxygen Species Research Personnel Resistance Rodent Rodent Model Role Site Sodium Testing Therapeutic Threonine Time Translating Triglycerides acronyms awake base citrate carrier dicarboxylate-binding protein endoplasmic reticulum stress fatty acid oxidation fly in vivo insight man new therapeutic target non-alcoholic fatty liver novel oxidation prevent

项目摘要

DESCRIPTION (provided by applicant): In this competing renewal a team of interdisciplinary investigators, who have an established track record of collaboration, will examine the cellular and molecular mechanisms of lipid-induced hepatic insulin resistance. Recent studies in both humans and rodent models of non alcoholic fatty liver disease (NAFLD) have led to a unifying diacylglycerol-hypothesis (DAG-hypothesis) for lipid-induced hepatic insulin resistance where accumulation of intracellular DAG activates protein kinase C5 (PKC5), directly leading to inhibition of insulin- stimulated insulin receptor kinase (IRK) activity. Specific Aim 1 wil explore the molecular mechanism by which activation of PKC5 leads to inhibition of IRK activity. This aim wil examine the hypothesis that PKC5 activation promotes increased threonine phosphorylation of IRK, which in turn blocks insulin-stimulated IRK activity, utilizing state-of-the-art LC-MS/MS methods to identify novel PKC5-induced IRK phosphothreonine sites. Specific Aim 2 wil further examine the DAG-hypothesis by examining the effect of a potential novel therapeutic target (INDY, acronym for I am Not Dead, Yet) on lipid-induced hepatic insulin resistance in awake whole body INDY knockout mice as well as awake rats with liver specific knockdown expression of INDY utilizing mRNA selective antisense oligonucleotides. INDY encodes a non-electrogenic dicarboxylate and citrate transporter and has been shown to promote longevity in a manner akin to caloric restriction in flies, but its role in mammals is unknown. This aim builds on our strong preliminary data demonstrating that INDY knockout mice exhibit increased whole body energy expenditure and are protected from lipid-induced whole body insulin resistance. Specific Aim 3 wil examine the mechanism by which knockdown of INDY in liver leads to increased whole body energy expenditure by employing a novel state-of-the-art 13C/31P NMR method to measure in vivo rates of hepatic fat oxidation, hepatic pyruvate oxidation, hepatic mitochondrial TCA flux, hepatic mitochondrial ATP synthesis and hepatic mitochondrial energy coupling in awake rats for the first time. This aim will examine the hypothesis that decreased hepatic expression of INDY will result in increased rates of hepatic mitochondrial TCA flux, increased rates of hepatic fatty acid oxidation, and decreased hepatic mitochondrial energy coupling, which results in lower hepatic DAG content and protection from lipid-induced hepatic insulin resistance. It is anticipated that the results from these studies will provide important new insights into the cellular mechanisms of NAFLD associated hepatic insulin resistance as well as the identification of a novel therapeutic target for the treatment of NALFD and T2D. Furthermore, once validated in these animal experiments, these 13C/31P NMR methods will be translated to man to directly assess liver specific rates of hepatic mitochondrial TCA flux, mitochondrial ATP synthesis and hepatic mitochondrial energy coupling in humans for the first time.

描述（由申请人提供）：在本次竞争更新中，一个由具有良好合作记录的跨学科研究人员组成的团队将研究脂质诱导的肝胰岛素抵抗的细胞和分子机制。最近对人类和啮齿动物非酒精性脂肪性肝病 (NAFLD) 模型的研究得出了脂质诱导的肝脏胰岛素抵抗的统一二酰甘油假说 (DAG 假说)，其中细胞内 DAG 的积累激活蛋白激酶 C5 (PKC5)，直接导致胰岛素刺激的胰岛素受体激酶（IRK）活性的抑制。具体目标 1 将探索 PKC5 激活导致 IRK 活性抑制的分子机制。该目标将检验以下假设：PKC5 激活促进 IRK 苏氨酸磷酸化增加，进而阻断胰岛素刺激的 IRK 活性，利用最先进的 LC-MS/MS 方法来识别新的 PKC5 诱导的 IRK 磷酸苏氨酸位点。具体目标 2 将通过检查潜在的新型治疗靶点（INDY，“我还没有死”的缩写）对清醒全身 INDY 敲除小鼠以及清醒小鼠中脂质诱导的肝脏胰岛素抵抗的影响，进一步检验 DAG 假设。利用 mRNA 选择性反义寡核苷酸进行肝脏特异性敲除 INDY 表达的大鼠。 INDY 编码非产电二羧酸盐和柠檬酸盐转运蛋白，并已被证明可以以类似于果蝇热量限制的方式延长寿命，但其在哺乳动物中的作用尚不清楚。这一目标建立在我们强有力的初步数据之上，这些数据表明 INDY 基因敲除小鼠表现出全身能量消耗增加，并且免受脂质诱导的全身胰岛素抵抗。具体目标 3 将通过采用最先进的 13C/31P NMR 方法测量体内肝脂肪氧化、肝丙酮酸氧化的速率，研究肝脏中 INDY 的敲低导致全身能量消耗增加的机制、首次在清醒大鼠中观察肝线粒体TCA通量、肝线粒体ATP合成和肝线粒体能量耦合。该目的将检验以下假设：INDY 的肝脏表达减少将导致肝线粒体 TCA 通量速率增加、肝脂肪酸氧化速率增加以及肝线粒体能量耦合减少，从而导致肝 DAG 含量降低并免受脂质-诱发肝脏胰岛素抵抗。预计这些研究的结果将为 NAFLD 相关肝胰岛素抵抗的细胞机制提供重要的新见解，并确定治疗 NALFD 和 T2D 的新治疗靶点。此外，一旦在这些动物实验中得到验证，这些 13C/31P NMR 方法将应用于人类，首次直接评估人类肝线粒体 TCA 通量、线粒体 ATP 合成和肝线粒体能量耦合的肝脏特定速率。

项目成果

期刊论文数量（163）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

UCP1-independent signaling involving SERCA2b-mediated calcium cycling regulates beige fat thermogenesis and systemic glucose homeostasis.

DOI：
10.1038/nm.4429
发表时间：
2017-12
期刊：
Nature medicine
影响因子：
82.9
作者：
Ikeda K;Kang Q;Yoneshiro T;Camporez JP;Maki H;Homma M;Shinoda K;Chen Y;Lu X;Maretich P;Tajima K;Ajuwon KM;Soga T;Kajimura S
通讯作者：
Kajimura S

Loss of insulin signaling in hepatocytes leads to severe insulin resistance and progressive hepatic dysfunction.

DOI：
10.1016/s1097-2765(05)00015-8
发表时间：
2000-07
期刊：
Molecular cell
影响因子：
16
作者：
M. Michael;R. Kulkarni;C. Postic;S. Previs;G. Shulman;M. Magnuson;C. Kahn
通讯作者：
M. Michael;R. Kulkarni;C. Postic;S. Previs;G. Shulman;M. Magnuson;C. Kahn

The deacetylase Sirt6 activates the acetyltransferase GCN5 and suppresses hepatic gluconeogenesis.

DOI：
10.1016/j.molcel.2012.09.030
发表时间：
2012-12-28
期刊：
MOLECULAR CELL
影响因子：
16
作者：
Dominy, John E., Jr.;Lee, Yoonjin;Jedrychowski, Mark P.;Chim, Helen;Jurczak, Michael J.;Camporez, Joao Paulo;Ruan, Hai-Bin;Feldman, Jessica;Pierce, Kerry;Mostoslavsky, Raul;Denu, John M.;Clish, Clary B.;Yang, Xiaoyong;Shulman, Gerald I.;Gygi, Steven P.;Puigserver, Pere
通讯作者：
Puigserver, Pere

Hypopituitarism associated with a hypothalamic CMV infection in a patient with AIDS.

艾滋病患者下丘脑 CMV 感染导致垂体功能减退症。