Sirt1 regulation of NFkB activation and inflammatory responses in sepsis

描述（由申请人提供）：感染性休克是一种系统性炎症反应综合征，可导致多器官损伤和死亡。目前，这种疾病没有有效的治疗方法。确定新的治疗靶点，可以帮助控制败血症引起的炎症是治疗这种毁灭性疾病的关键。复杂炎症网络的激活是脓毒症中过度全身炎症反应的原因。NF-kB已被证明是脓毒症中调节这些炎症网络的核心参与者。然而，NF-kB活性在脓毒症中的分子调控在很大程度上仍然未知。近年来的研究表明，乙酰化是NF-kB活化的一种新机制。据报道，Sirt1是一种在所有组织中广泛表达的去乙酰化酶，在几种体外和体内系统中与NF-kB相互作用并通过去乙酰化抑制NF-kB活性。然而，Sirt1在脓毒症诱导的炎症反应中的功能和调控尚未被研究。通过小鼠脓毒症模型，我们证明Sirt1通过调节NF-kB乙酰化和激活来控制脓毒症期间的炎症反应。我们的初步数据显示，在野生型小鼠中，脓毒症的诱导触发了NF-kB乙酰化和活化，在Sirt1敲除小鼠中进一步增加。有趣的是，通过白藜芦醇或Sirt1基因传递激活Sirt1可抑制败血症诱导的NF-kB乙酰化。此外，我们发现caspase激活导致Sirt1降解，这可能是脓毒症中加重全身性炎症的新途径。在拟议的研究中，我们将验证Sirt1在败血症期间控制NF-k B激活和炎症反应的假设。我们的具体目标是：(1)确定Sirt1在败血症诱导的NF-kB激活和全身性炎症中的作用。我们将使用可诱导的Sirt1敲除小鼠来评估Sirt1在败血症诱导的全身性炎症中的作用；我们将研究caspase在败血症期间Sirt1调节NF-kB激活和炎症信号传导中的作用；(2)特异性剖析Sirt1在脓毒症期间内皮细胞炎症反应中对NF-kB活化的控制。我们将定义Sirt1对脓毒症诱导的NF-kB激活和内皮细胞炎症信号的控制。我们将使用内皮特异性Sirt1敲除小鼠来评估内皮Sirt1在败血症中NF-kB调节和炎症信号传导中的作用；(3)探讨Sirt1激活剂调节NF-kB激活和Sirt1基因传递在败血症诱导炎症中的治疗潜力。我们将探索Sirt1激活剂对败血症诱导的NF-kB激活和炎症信号的治疗潜力；我们将评估Sirt1基因传递是否可以通过抑制nf - kb调节的炎症信号有效地保护败血症诱导的炎症。上述研究的成功完成将揭示Sirt1作为败血症诱导的NF-kB激活和炎症的新型调节剂，并验证Sirt1作为治疗败血症相关炎症组织损伤的治疗靶点的潜力。

DESCRIPTION (provided by applicant): Septic shock is a systemic inflammatory response syndrome that causes multiple organ damage and death. Currently, there is no efficient treatment for the disease. Identifying novel therapeutic targets that can help control sepsis-induced inflammation is crucial to treat this devastating disease. Activation of complex inflammatory networks is responsible for the excessive systemic inflammatory response in sepsis. NF-kB has been demonstrated as a central player that regulates these inflammatory networks in sepsis. However, molecular regulation of NF-kB activity in sepsis remains largely unknown. Recent studies indicate that acetylation is a new mechanism in NF-kB activation. It has been reported that Sirt1, a deacetylase widely expressed in all tissues, interacts with NF-kB and inhibits NF-kB activity by deacetylation in several in vitro and in vivo systems. Yet, the function and regulation of Sirt1 in sepsis-induced inflammatory responses have not been studied. Using mouse models of sepsis, we demonstrate that Sirt1 controls inflammatory responses during sepsis by regulating NF-kB acetylation and activation. Our preliminary data showed that induction of sepsis triggered NF-kB acetylation and activation in wild type mice, which were further increased in Sirt1 knockout mice. Interestingly, Sirt1 activation by resveratrol or Sirt1 gene delivery inhibited sepsis-induced NF-kB acetylation. Furthermore, we showed that caspase activation resulted in Sirt1 degradation, which may function as a new pathway to aggravate systemic inflammation in sepsis. In the proposed studies, we will test the hypothesis that Sirt1 controls NF-k B activation and inflammatory responses during sepsis. Our specific aims are: (1) to define the role of Sirt1 in sepsis-induced NF-kB activation and systemic inflammation. We will use inducible Sirt1 knockout mice to assess the role of Sirt1 in sepsis-induced systemic inflammation; we will examine the role of caspase in Sirt1 regulation of NF-kB activation and inflammatory signaling during sepsis; (2) to specifically dissect Sirt1 control of NF-kB activation in endothelial cell inflammatory responses during sepsis. We will define Sirt1 control of sepsis-induced NF-kB activation and inflammatory signaling in endothelial cells. We will use endothelial-specific Sirt1 knockout mice to assess the role of endothelial Sirt1 in NF-kB modulation and inflammatory signaling in sepsis; (3) to explore the therapeutic potential of modulating NF-kB activation by Sirt1 activators and Sirt1 gene delivery in sepsis-induced inflammation. We will explore the therapeutic potential of Sirt1 activators on sepsis-induced NF-kB activation and inflammatory signaling; we will evaluate whether Sirt1 gene delivery can effectively protect against sepsis-induced inflammation by inhibiting NF-kB-regulated inflammatory signaling. Successful completion of the proposed studies will disclose Sirt1 as a novel modulator of sepsis-induced NF-kB activation and inflammation, and validate the potential of Sirt1 as a therapeutic target to treat sepsis-associated inflammatory tissue damage.