Muscle Protein Turnover and Amino Acid Uptake in Sepsis

脓毒症中的肌肉蛋白质周转和氨基酸摄取

基本信息

批准号：
7641055
负责人：
PER-OLOF J HASSELGREN
金额：
$ 29.85万
依托单位：
BETH ISRAEL DEACONESS MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
1987
资助国家：
美国
起止时间：
1987-01-01 至 2011-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7641055
关键词：
Amino Acids Automobile Driving CCAAT-Enhancer-Binding Proteins Calcium Calcium Channel Blockers Calcium/calmodulin-dependent protein kinase Calmodulin Calpain Chelating Agents Corticosterone Dantrolene Dexamethasone Enzymes Funding Gases Gene Expression Genes Glucocorticoids In Vitro Injury Laboratories Ligation Malignant Neoplasms Measures Mediator of activation protein Messenger RNA Modeling Morbidity - disease rate Muscle Muscle Cells Muscle Development Muscle Fibers Muscle Proteins NF-kappa B Pathway interactions Patients Plasmids Prevention Proteins Proteolysis Puncture procedure Rattus Regulation Research Personnel Role Scheme Sepsis Silicon Dioxide Skeletal Muscle Small Interfering RNA Testing Ubiquitin Up-Regulation Verapamil Work calmodulin-dependent protein kinase II calpain inhibitor calpastatin factor C improved inhibitor/antagonist m-calpain mortality multicatalytic endopeptidase complex muscle form overexpression programs protein degradation research study septic therapeutic target transcription factor ubiquitin ligase uptake wasting

项目摘要

DESCRIPTION (provided by applicant): Previous studies suggest that sepsis-induced muscle wasting is associated with increased muscle calcium levels and that glucocorticoids are the predominant mediator of sepsis-induced muscle proteolysis. The overall hypothesis of the current project is that glucocorticoids increase muscle calcium levels and that sepsis and glucocorticoids increase muscle proteolysis through calcium-dependent mechanisms. This is tested in 3 specific aims. Specific Aim 1 tests the hypothesis that sepsis and glucocorticoids increase muscle calcium levels and calcium-calmodulin protein kinase II (CaMK II) and calpain activities. Specific Aim 2 tests the hypothesis that sepsis- and glucocorticoid-induced activation of the muscle wasting-associated transcription factors C/EBPp and 8 and NF-kB is regulated by increased calcium levels and activation of CaMK II and calpains. Specific Aim 3 tests the hypothesis that sepsis- and glucocorticoid-induced muscle proteolysis and upregulation of the ubiquitin ligases atrogin-1 arid MuRF1 are regulated by increased calcium levels and activation of CaMK II and calpains. Studies are performed in two models of muscle wasting, i.e., in septic rats and in dexamethasone-treated cultured myotubes. In several previous studies, we have found that sepsis in rats induced by cecal ligation and puncture (CLP) and treatment of cultured myotubes with dexamethasone result in increased protein degradation and upregulated gene expression of the ubiquitin-proteasome-proteolytic pathway. The role of calcium is examined by using the calcium chelator BAPTA or the calcium "antagonists" verapamil and dantrolene. The roles of CaMK II and calpains are tested by using specific inhibitors or by transfecting myocytes with plasmids expressing the enzymes or the natural calpain inhibitor calpastatin. The project is important because it will provide information about early and initiating mechanisms of sepsis- and glucocorticoid-induced muscle wasting, if our hypothesis is correct, calcium-regulated mechanisms may become important therapeutic targets in the prevention and treatment of muscle wasting in sepsis and other catabolic conditions. Relevance: Patients with sepsis, cancer, or injury suffer loss of muscle mass. Muscle wasting in these and other catabolic conditions contributes significantly to morbidity and mortality. The proposed experiments will define the role of calcium and calcium-regulated mechanisms in the development of muscle-wasting in sepsis. Increased understanding of the mechanisms driving muscle wasting will help improve prevention and treatment of this debilitating condition.

描述（由申请人提供）：先前的研究表明，脓毒症引起的肌肉萎缩与肌肉钙水平增加有关，并且糖皮质激素是脓毒症引起的肌肉蛋白水解的主要介质。当前项目的总体假设是糖皮质激素增加肌肉钙水平，脓毒症和糖皮质激素通过钙依赖性机制增加肌肉蛋白水解。这是在 3 个具体目标中进行测试的。具体目标 1 检验脓毒症和糖皮质激素增加肌肉钙水平、钙钙调蛋白激酶 II (CaMK II) 和钙蛋白酶活性的假设。具体目标 2 测试了以下假设：脓毒症和糖皮质激素诱导的肌肉消耗相关转录因子 C/EBPp 和 8 以及 NF-kB 的激活受到钙水平增加以及 CaMK II 和钙蛋白酶激活的调节。具体目标 3 测试了以下假设：脓毒症和糖皮质激素诱导的肌肉蛋白水解以及泛素连接酶 atrogin-1 和 MuRF1 的上调是通过钙水平增加以及 CaMK II 和钙蛋白酶的激活来调节的。研究在两种肌肉萎缩模型中进行，即脓毒症大鼠和地塞米松处理的培养肌管。在之前的几项研究中，我们发现盲肠结扎穿刺（CLP）以及用地塞米松处理培养的肌管引起的大鼠脓毒症会导致蛋白质降解增加和泛素-蛋白酶体-蛋白水解途径的基因表达上调。通过使用钙螯合剂 BAPTA 或钙“拮抗剂”维拉帕米和丹曲林来检查钙的作用。 CaMK II 和钙蛋白酶的作用通过使用特定抑制剂或通过用表达酶或天然钙蛋白酶抑制剂钙蛋白酶抑制素的质粒转染肌细胞来测试。该项目很重要，因为它将提供有关脓毒症和糖皮质激素引起的肌肉萎缩的早期和起始机制的信息，如果我们的假设正确，钙调节机制可能成为预防和治疗脓毒症和糖皮质激素引起的肌肉萎缩的重要治疗靶点。其他分解代谢状况。相关性：患有败血症、癌症或受伤的患者会遭受肌肉质量损失。在这些和其他分解代谢条件下的肌肉萎缩会显着增加发病率和死亡率。拟议的实验将确定钙和钙调节机制在脓毒症肌肉萎缩发展中的作用。加深对导致肌肉萎缩的机制的了解将有助于改善这种使人衰弱的疾病的预防和治疗。