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Determining the Biological Effects of Mitochondrial Acyl Toxicity

确定线粒体酰基毒性的生物学效应

基本信息

批准号：
10428562
负责人：
Jessica M Ellis
金额：
$ 46.39万
依托单位：
EAST CAROLINA UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-01 至 2025-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10428562
关键词：
Acute Agreement Animal Model Biochemical Bioenergetics Biological Biological Assay Biological Models Biology Calcium Calcium Channel Carnitine Carnitine Palmitoyltransferase I Cell physiology Cells Chronic Clinical Coenzyme A Coenzyme A Ligases Complex Confounding Factors (Epidemiology)Consumption Coupled Cytosol Data Defect Diabetes Mellitus Enzymes Equilibrium Etiology Exercise Tolerance Fatigue Functional disorder Genetic Health High Fat Diet Homeostasis Human Impairment Inner mitochondrial membrane Insulin Resistance Knockout Mice Link Literature Metabolic Metabolic Diseases Metabolic stress Metabolism Mitochondria Modeling Mus Muscle Muscle Fibers Muscle function Muscular Atrophy Obesity Obesity Epidemic Outcome Oxidative Phosphorylation Pathway interactions Phenotype Physiological Physiological Processes Pre-Clinical Model Process Production Reaction Recovery Rhabdomyolysis Role Sarcoplasmic Reticulum Skeletal Muscle Soleus Muscle Source Structure Surface Testing Therapeutic Toxic effect Work acylcarnitine deprivation exercise capacity fatty acid oxidation in vivo insight insulin sensitivity insulin signaling lipid metabolism mitochondrial dysfunction mouse model novel overexpression oxidation skeletal muscle weakness therapeutic development translocase

项目摘要

PROJECT SUMMARY During acute metabolic stress and chronic metabolic disease, such as obesity and diabetes, the accumulation of fatty acid oxidation intermediary metabolites has long been suspected of toxicity. Among these possible lipotoxic metabolites are long-chain acylcarnitines (LCACs), which purportedly interfere with critical physiological processes including insulin signaling, calcium homeostasis, and mitochondrial function. However, mechanistically linking defects in these processes to LCAC accumulation has been difficult due to a lack of LCAC-accumulating pre-clinical models. We overcame this barrier by developing a unique mouse model of LCAC accumulation by deleting the enzyme that catabolizes LCACs, carnitine palmitoyltransferase-2 specifically in skeletal muscle (Cpt2Sk-/-). Consistent with the suspected roles of LCACs effects on biology, our preliminary data demonstrate that Cpt2Sk-/- muscles have reduced force production and mitochondrial dysfunction. Our preliminary data also demonstrate large accumulation of LCACs within oxidative muscle fibers, thus are the most vulnerable to potential LCAC toxicity. While our Cpt2Sk-/- model provides consistently elevated LCACs, the physiological outcomes are confounded by energy deprivation due to mitochondrial FAO deficiency. To mitigate concerns surrounding this confounding variable, we will employ three complimentary mouse models of muscle- specific FAO deficiency: 1) Cpt2Sk-/- that accumulate LCACs across the cell; 2) carnitine acylcarnitine translocase (CactSk-/-) mice that accumulate LCACs outside of the mitochondria; and 3) acyl-CoA synthetase 1 (Acsl1Sk-/-) mice that do not accumulate LCACs at all. Here, we will use this three-model system to determine the role of LCACs on insulin signaling, calcium homeostasis, and mitochondrial function. Results will be the first to provide requisite experimental contrast to unveil direct versus indirect effects of LCACs on cell physiology.

项目摘要在急性代谢应激和慢性代谢疾病，如肥胖和糖尿病，积累脂肪酸氧化中间代谢产物的毒性一直被怀疑。在这些可能脂毒性代谢物是长链酰基肉毒碱（LCAC），据称其干扰关键的生理学作用。这些过程包括胰岛素信号传导、钙稳态和线粒体功能。然而，在这方面，将这些过程中的缺陷与LCAC积累机械地联系起来是困难的，这是由于缺乏 LCAC累积临床前模型。我们通过开发一种独特的小鼠模型，通过删除分解代谢LCAC的酶，肉毒碱棕榈酰转移酶-2，在骨骼肌中（Cpt 2Sk-/-）。与LCACs对生物学影响的怀疑作用一致，我们的初步研究结果表明，数据表明Cpt 2Sk-/-肌肉具有减少的力产生和线粒体功能障碍。我们初步数据还表明，LCAC在氧化肌纤维内大量积累，因此是最常见的。易受潜在LCAC毒性的影响。虽然我们的Cpt 2Sk-/-模型提供了持续升高的LCAC，生理结果被由于线粒体FAO缺乏引起的能量剥夺所混淆。以减轻考虑到这个混淆变量，我们将采用三种互补的肌肉小鼠模型，特异性FAO缺陷：1）Cpt 2Sk-/-，其在整个细胞中积累LCAC; 2）肉毒碱酰基肉毒碱移位酶（CactSk-/-）小鼠，其在线粒体外积累LCAC;和3）酰基-CoA合成酶1（AcsllSk-/-）完全不积累LCAC的小鼠。在这里，我们将使用这三个模型系统来确定 LCACs对胰岛素信号传导、钙稳态和线粒体功能的影响。结果将首先提供必要的实验对比，以揭示LCAC对细胞生理学的直接与间接影响。