A therapeutic approach to muscle wasting by limiting protein breakdown

通过限制蛋白质分解来治疗肌肉萎缩的方法

基本信息

批准号：
7223331
负责人：
JEFFREY J BRAULT
金额：
$ 5.29万
依托单位：
HARVARD MEDICAL SCHOOL
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-08-01 至 2010-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7223331
关键词：
Acquired Immunodeficiency Syndrome Acute Adult Animal Model Atrophic Autophagocytosis Biological Assay Bortezomib Cachexia Complex Complication Cultured Cells Cushing Syndrome Data Denervation Diabetes Mellitus Disuse Atrophy Dose Duchenne muscular dystrophy Dystroglycan Dystrophin Fasting Glucocorticoids Glycoproteins Goals Incubated Individual Isometric Exercise Lead Learning Life Lysosomes MG132 Malignant Neoplasms Measures Mus Muscle Muscle Cells Muscle Proteins Muscle denervation procedure Muscle function Muscular Atrophy Muscular Dystrophies Mutate PS341 cpd Pathway interactions Pharmacologic Substance Polymerase Chain Reaction Process Proteasome Inhibition Proteasome Inhibitor Protein Biosynthesis Proteins Proteolysis Publishing Rate Relative (related person)Research Rodent Signal Transduction Systemic disease Testing Therapeutic Time Transcriptional Regulation Ubiquitin Velcade Western Blotting Work cancer therapy improved in vivo inhibitor/antagonist insight mdx mouse mouse model multicatalytic endopeptidase complex mutant prevent protein degradation response time use transcription factor ubiquitin ligase wasting

项目摘要

DESCRIPTION (provided by applicant): Muscle atrophy occurs with disuse, muscular dystrophy, glucocorticoid treatment (as in Cushing's syndrome), and with many systemic diseases (e.g. cancer cachexia, diabetes, fasting), when overall rates of protein degradation exceed protein synthesis. Most types of atrophy have a general increase in degradation of intracellular proteins mainly through the ubiquitin(Ub)-proteasome pathway and share a common set of transcriptional changes. Currently, no effective pharmaceutical treatments for atrophy are available. Work on proteasome inhibitors and the transcriptional regulation of the Ub- proteasome pathway has suggested that the proteasome is an excellent target. However, my recent studies with cell culture suggest that the lysosomal (autophagic) process also contributes to protein loss. Studying mouse models of muscle wasting with very different causes (denervation, glucocorticoid administration, and mdx mice - a muscular dystrophy), I have three aims. 1) To determine to what extent the lysosmal and proteasomal pathways contribute to denervation and glucocorticoid-induced atrophy, I will use specific inhibitors of these pathways while measuring overall protein degradation rates in incubated muscles. 2) To learn how Velcade, a specific proteasome inhibitor approved for cancer therapy, can influence protein breakdown during denervation atrophy in adult mice, I will quantify muscle protein fractions, isometric contractile ability in incubated muscle and determine the molecules that activate these pathways by using real-time PCR and Western blotting for known transcription factors or ubiquitin ligases. (Denervation atrophy would be expected to be activated via the FOXO transcription factors or possibly through NFkB.) 3) To explore the efficacy of Velcade administraction to mdx mice, I will test whether Velcade, which can increase dystrophin content, can improve dytrophic muscle contractile function in isolated muscles and whether the increased content of mutant dystrophin it due to specific effects on this short-lived protein or a result of effects on overall protein degradation (by Western blotting and specific protein degradation assays). Taken together, these studies should advance our long-term goal of developing viable therapies for muscle wasting. RELEVANCE. Muscle wasting is an often debilitating complication of muscle disuse, fasting and many systemic diseases such as cancer, AIDS, or muscular dystrophy. Since these muscle atrophies share many common features, our research on therapies and mechanisms of slowing protein breakdown may lead to a viable treatment for these individuals.

描述（由申请人提供）：当蛋白质降解的总体速率超过蛋白质合成时，废用、肌营养不良、糖皮质激素治疗（如库欣综合征）以及许多全身性疾病（例如癌症恶病质、糖尿病、禁食）会发生肌肉萎缩。大多数类型的萎缩主要通过泛素 (Ub)-蛋白酶体途径导致细胞内蛋白质降解普遍增加，并具有一组共同的转录变化。目前，尚无有效的萎缩药物治疗方法。对蛋白酶体抑制剂和 Ub-蛋白酶体途径转录调控的研究表明，蛋白酶体是一个极好的靶标。然而，我最近对细胞培养的研究表明，溶酶体（自噬）过程也会导致蛋白质损失。通过研究不同原因引起的肌肉萎缩小鼠模型（去神经支配、给予糖皮质激素和 mdx 小鼠——一种肌肉萎缩症），我有三个目标。 1）为了确定溶酶体和蛋白酶体途径在多大程度上导致去神经支配和糖皮质激素诱导的萎缩，我将使用这些途径的特定抑制剂，同时测量孵化肌肉中的总体蛋白质降解率。 2) 为了了解 Velcade（一种被批准用于癌症治疗的特定蛋白酶体抑制剂）如何影响成年小鼠去神经萎缩过程中的蛋白质分解，我将量化肌肉蛋白质分数、孵化肌肉的等长收缩能力，并通过使用确定激活这些途径的分子针对已知转录因子或泛素连接酶的实时 PCR 和蛋白质印迹。（去神经萎缩预计将通过 FOXO 转录因子或可能通过 NFkB 激活。） 3）为了探索 Velcade 对 mdx 小鼠给药的功效，我将测试可以增加肌营养不良蛋白含量的 Velcade 是否可以改善营养不良的肌肉收缩分离肌肉中的功能以及突变型抗肌营养不良蛋白含量的增加是否是由于对这种短寿命蛋白质的特定影响或对整体蛋白质降解的影响的结果（通过蛋白质印迹和特定蛋白质降解测定）。总而言之，这些研究应该会推进我们开发可行的肌肉萎缩疗法的长期目标。关联。肌肉萎缩是肌肉废用、禁食和许多全身性疾病（如癌症、艾滋病或肌营养不良）的常见并发症。由于这些肌肉萎缩有许多共同特征，我们对减缓蛋白质分解的疗法和机制的研究可能会为这些个体带来可行的治疗方法。