Respiration in Sepsis

描述（由申请人提供）： 这个VA Merit Review更新申请建议研究实验性S。金黄色脓毒症由于老年退伍军人中脓毒症引起的多器官功能障碍综合征（MODS）的高患病率和高成本，这一领域的基础研究需求很高。这种高死亡率综合征部分是由于线粒体损伤，这是机制知之甚少。利用早期的资金，我们发现败血症中的线粒体生物合成在能量危机之前被激活，而救援途径被延迟，涉及腺苷一磷酸（AMP）激活的蛋白激酶（AMPK）和PGC-1辅激活剂。新的初步数据将AMPK激活与脓毒症中的一氧化氮合酶-2（NOS 2）诱导联系起来，不需要高AMP/ATP，并且一氧化氮合酶-2（NOS 2）缺陷小鼠中AMPK激活的丧失伴随着炎症恶化。AMPK可以作为三个关键的转录因子- CREB，NRF-1和NRF- 2（GABPA）的激活剂，用于脓毒症中的线粒体生物合成，但NO调节也通过NO信号特异性的丧失和NO物质（NOx）对线粒体的无差别化学攻击诱导线粒体损伤。我们认为，AMPK激活即将发生的能量衰竭上调线粒体损伤控制程序在脓毒症，如果是这样，NO非依赖性药理学AMPK激活可以控制过量的NO生产和减轻脓毒症诱导的MODS。我们将重点关注AMPK在肝脏，一个哨兵器官，和NOS 2作为一个定量的影响线粒体周转和细胞凋亡使用药理学AMPK激活，以限制NO诱导的线粒体损伤。我们的具体目标是：目标1：了解脓毒症中肝脏AMPK活化与NOS 2诱导、线粒体生物合成程序和细胞凋亡预防的关系。 1A.使用NOS 2基因滴定法确定AMPK激活与NOx介导的mtDNA和蛋白质损伤、呼吸能力、高能代谢物和脓毒症诱导的肝细胞死亡之间的关系。 1B.确定AMPK激活是否通过NO依赖性CREB/NRF-1活性促进线粒体生物合成和抑制促凋亡Bad和BNIP 3的磷酸化，从而防止脓毒症中的细胞凋亡。 目标二：确定在脓毒症中，激活或抑制AMPK的特异性策略是否独立于NOS 2调节肝线粒体生物合成和细胞存活，并减轻NO依赖性细胞损伤。 2A.确定AMPK的药理学激活是否独立于NOS 2促进线粒体生物合成和/或抑制脓毒症中的细胞凋亡。我们还将使用高通量筛选来鉴定一种或多种新型AMPK选择性激动剂。 2B.使用CREB和PGC-1作为关键读数，比较NO依赖性和NO非依赖性AMPK激活对脓毒症线粒体生物合成转录调控的影响。 这些研究将提供新的分子数据AMPK调节线粒体生物合成败血症，在何种程度上，NO的生产是监管。概念验证将导致合理的药理学方法来激活和支持线粒体生物合成，同时最大限度地减少NO诱导的附带损伤。 了解这些基本的调控机制是设计前瞻性的治疗方法，以保护线粒体质量控制败血症。

DESCRIPTION (provided by applicant): This VA Merit Review renewal application proposes to study transcriptional regulation of the pro-survival program of mitochondrial biogenesis during experimental S. aureus sepsis. The need for basic research in this area is high due to the high prevalence and cost of sepsis-induced multiple organ dysfunction syndrome (MODS) in older Veterans. This high mortality syndrome is due in part to mitochondrial damage, which is mechanistically poorly understood. Using earlier funding, we discovered that mitochondrial biogenesis in sepsis is activated before energy crisis, while a rescue pathway is delayed involving the adenosine monophosphate (AMP)-activated protein kinase (AMPK) and PGC-1� co-activator. New preliminary data links AMPK activation to nitric oxide synthase-2 (NOS2) induction in sepsis, does not require high AMP/ATP, and loss of AMPK activation in nitric oxide synthase-2 (NOS2) deficient mice is accompanied by worsening inflammation. AMPK may serve as an activator of three crucial transcription factors- CREB, NRF-1, and NRF- 2 (GABPA) for mitochondrial biogenesis in sepsis, but NO regulation also induces mitochondrial damage by loss of NO signal specificity and indiscriminate chemical attack on mitochondria by NO species (NOx). We propose that AMPK activation by impending energy failure up-regulates the mitochondrial damage control program in sepsis and if so, NO-independent pharmacological AMPK activation could control excess NO production and mitigate sepsis-induced MODS. We will focus on AMPK in the liver, a sentinel organ, and NOS2 as a quantitative influence on mitochondrial turnover and apoptosis using pharmacological AMPK activation to limit NO-induced mitochondrial damage. Our Specific Aims are: Aim 1: To understand hepatic AMPK activation in sepsis in relation to NOS2 induction, the program of mitochondrial biogenesis, and the prevention of apoptosis. 1A. Define the relationships between AMPK activation and NOx-mediated mtDNA and protein damage, respiratory capacity, high-energy metabolites, and sepsis-induced hepatic cell death using NOS2 gene titration. 1B. Determine if AMPK activation through NO-dependent CREB/NRF-1 activity promotes mitochondrial biogenesis and inhibitory phosphorylation of pro-apoptotic Bad and BNIP3, preventing apoptosis in sepsis. Aim 2: To determine if specific strategies to activate or inhibit AMPK independently of NOS2 regulate hepatic mitochondrial biogenesis and cell survival and lessen NO-dependent cell damage in sepsis. 2A. Determine if the pharmacological activation of AMPK independently of NOS2 promotes mitochondrial biogenesis and/or inhibits apoptosis in sepsis. We will also use high-throughput screening to identify one or more novel selective agonists of AMPK. 2B. Compare NO-dependent and NO-independent AMPK activation for effects on the transcriptional regulation of mitochondrial biogenesis in sepsis using CREB and PGC-1� as key readouts. These studies will provide new molecular data on AMPK regulation of mitochondrial biogenesis in sepsis, and on the extent to which NO production is regulatory. Proof-of-concept would lead to rational pharmacological approaches to activate and support mitochondrial biogenesis while minimizing NO-induced collateral damage. Understanding these fundamental regulatory mechanisms is needed to design forward-thinking therapeutic approaches to protect mitochondrial quality control during sepsis.