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）：需要机械通气的重症患者的呼吸肌肉非常弱，感染是导致这种张力发展的主要因素。然而，全身感染诱导呼吸道肌肉无力的细胞机制知之甚少。在其他组织中，感染的作用是由多种信号通路介导的，但是几乎没有什么知之甚少。本提案中实验的目的是检查此问题。这些实验将检验我们的中心假设：p38，JNK和PKR激酶途径相互作用以调节diaphragm肌肉死亡受体激活，死亡受体活性caspase 8的形成以及caspase介导的粘膜力的减少。 AIM I研究将检验以下假设：p38和JNK调节炎症引起的骨骼肌caspase 8激活和收缩功能障碍。将使用给定内毒素和C2C12肌肉细胞的小鼠进行研究。我们将检查p38和JNK的激活时间过程，还将确定p38和/或JNK的化学或遗传抑制是否会阻止炎症诱导的caspase 8形成和隔膜弱点。我们还将确定NADPH氧化酶介导的超氧化物产生是否会导致骨骼肌p38和JNK激活，以响应炎症。 AIM II研究将检验以下假设：PKR还有助于炎症引起的骨骼肌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的化学或遗传抑制是否可以防止炎症诱导骨骼肌caspase 8的形成和无力。我们还将确定炎症刺激后，Pact/RAX激活是否负责激活骨骼肌中的PKR。 AIM III研究将检验以下假设：炎症会诱导与p38，JNK和PKR信号通路的激活有关的骨骼肌死亡受体复合物（DIS）特征的特定变化。我们都将表征炎症对椎间盘形成，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信号传导途径来阻止这些改变。