MAPK/PKR Modulation of Diaphragm Weakness

MAPK/PKR 膈肌无力的调节

• 批准号: 7146879
• 负责人: GERALD S. SUPINSKI
• 金额: $ 11.63万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2007-01-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7146879
• 关键词: JUN kinase; NAD(P)H dehydrogenase; apoptosis; biological signal transduction; cell line; cysteine endopeptidases; diaphragm; endotoxins; enzyme activity; enzyme induction /repression; inflammation; kinase inhibitor; laboratory mouse; mitogen activated protein kinase; muscle contraction; muscle strength; myotubes; protein kinase; protein localization; proteomics; receptor expression; tumor necrosis factor alpha; western blottings

DESCRIPTION (provided by applicant): The respiratory muscles of critically ill patients requiring mechanical ventilation are profoundly weak and infections are a major factor contributing to the development of this debility. The cellular mechanisms by which systemic infection induces respiratory muscle weakness, however, are poorly understood. In other tissues, the effects of infection are mediated by a variety of signaling pathways but virtually nothing is known about the signaling pathways activated in respiratory skeletal muscle in response to infection. The purpose of the experiments in this proposal is to examine this issue. These experiments will test our central hypothesis: p38, JNK, and PKR kinase pathways interact to regulate diaphragm muscle death receptor activation, death receptor active caspase 8 formation, and caspase mediated reductions in diaphragm force generation. Aim I studies will test the hypothesis that p38 and JNK modulate inflammation induced skeletal muscle caspase 8 activation and contractile dysfunction. Studies will be done using mice given endotoxin and C2C12 muscle cells exposed to cytokines. We will examine the time course of activation of p38 and JNK and will also determine if chemical or genetic inhibition of p38 and/or JNK prevents inflammation induced caspase 8 formation and diaphragm weakness. We will also determine if NADPH oxidase mediated superoxide generation causes skeletal muscle p38 and JNK activation in response to inflammation. Aim II studies will test the hypothesis that PKR also contributes to inflammation induced skeletal muscle caspase 8 activation and weakness. We will examine the time course of skeletal muscle PKR activation and will determine if chemical or genetic inhibition of PKR prevents inflammation induced skeletal muscle caspase 8 formation and weakness. We will also determine if PACT/RAX activation is responsible for activating PKR in skeletal muscle following inflammatory stimuli. Aim III studies will test the hypothesis that inflammation induces specific changes in skeletal muscle death receptor complex (DISC) characteristics that are linked to activation of the p38, JNK and PKR signaling pathways. We will both characterize the effects of inflammation on DISC formation, localization, and autocatalytic activity and determine if these alterations can be blocked by inhibition of p38, JNK, and/or PKR signaling pathways.

描述（由申请人提供）：需要机械通气的危重患者的呼吸肌非常虚弱，感染是导致这种虚弱的一个主要因素。然而，人们对全身感染引起呼吸肌无力的细胞机制知之甚少。在其他组织中，感染的影响是由多种信号通路介导的，但实际上对呼吸骨骼肌中响应感染而激活的信号通路一无所知。本提案中实验的目的是研究这个问题。这些实验将检验我们的中心假设：p38、JNK 和 PKR 激酶通路相互作用，调节膈肌死亡受体激活、死亡受体活性 caspase 8 形成以及 caspase 介导的膈肌力产生减少。目标 I 研究将检验 p38 和 JNK 调节炎症诱导的骨骼肌 caspase 8 激活和收缩功能障碍的假设。研究将使用给予内毒素和暴露于细胞因子的 C2C12 肌细胞的小鼠进行。我们将检查 p38 和 JNK 激活的时间过程，并将确定 p38 和/或 JNK 的化学或遗传抑制是否可以防止炎症诱导的 caspase 8 形成和膈肌无力。我们还将确定 NADPH 氧化酶介导的超氧化物生成是否会导致骨骼肌 p38 和 JNK 激活以应对炎症。 Aim II 研究将检验以下假设：PKR 也有助于炎症诱导的骨骼肌 caspase 8 激活和无力。我们将检查骨骼肌 PKR 激活的时间过程，并确定 PKR 的化学或基因抑制是否可以防止炎症诱导的骨骼肌 caspase 8 形成和衰弱。我们还将确定 PACT/RAX 激活是否负责在炎症刺激后激活骨骼肌中的 PKR。 Aim III 研究将检验以下假设：炎症会引起骨骼肌死亡受体复合物 (DISC) 特征的特定变化，这些变化与 p38、JNK 和 PKR 信号通路的激活有关。我们将描述炎症对 DISC 形成、定位和自催化活性的影响，并确定是否可以通过抑制 p38、JNK 和/或 PKR 信号通路来阻断这些改变。