Fra-1-A20 Signaling and Resolution of Pneumonia-Induced Sepsis

促炎症基因和抗炎基因转录的平衡对于正常 脓毒症组织损伤后的动态平衡。对这种转录平衡的异常调节达到顶峰 在不加控制的全身性炎症中，导致肺组织损伤和浮肿，呼吸道 失败，最终死亡。然而，病理性炎症背后的确切机制 脓毒症的发病机制知之甚少，因此加速败血症消退的策略是 非常有限。该提案中的研究将检验致病信号的新假设 脓毒症是巨噬细胞特异性Fra-1/AP-1限制性表达的结果 炎症性A20，一种关键的泛素编辑酶，终止核因子-2的不受控制的激活 κB和MAP激酶信号转导。我们的初步研究，使用了三种败血症的临床前模型， 表明Fra-1在脓毒症的促炎反应中是一个重要的介质。内毒素血症 (LP)-和假单胞菌肺炎引起的肺损伤和炎症在 FRA-1基因缺失的小鼠比野生型小鼠更容易受到影响。FRA-1基因缺陷小鼠受到损伤性剂量的 与野生型相比，I.T细菌内毒素(LPS)对肺损伤的缓解更快 老鼠。我们发现，在身体肺的肺泡巨噬细胞中，Fra-1的表达增加。 在体外感染大肠杆菌和暴露于脂多糖的小鼠。重要的是，髓系中缺乏Fra-1的小鼠 在败血症休克和多菌败血症中，细胞存活时间比野生型小鼠更长。在预赛中 研究发现，内毒素诱导的NF-κB活性水平降低，而 FRA-1缺乏的巨噬细胞中的A20。在人类和小鼠身上的A20单倍性与 全身炎症水平升高。我们将解决特定的假设，即在 继发于微生物损伤的慢性或病理性脓毒症FrA-1激活的环境限制 最佳的A20表达并触发促炎反应，从而损害对 败血症。我们将使用生理和分子方法和组织特异性基因敲除小鼠和 败血症的临床前模型来验证这一假说。该提案的具体目的是：1) 确定巨噬细胞特异性Fra-1信号转导途径的作用和机制 假单胞菌肺炎和脓毒症的持续性肺损伤，以及2)通过 哪个Fra-1限制了微生物对巨噬细胞A20转录的诱导，以及 确定Fra-1限制性A20信号通路是持续性肺损伤的致病因素 败血症。拟议的研究将为加速肺部的治疗确定新的见解和靶点。 假单胞菌肺炎合并败血症患者的损伤修复。

The counter balancing of pro- and anti-inflammatory gene transcription is crucial for normal homeostasis after septic tissue injury. Aberrant regulation of this transcriptional balance culminates in an unchecked systemic inflammation, leading to lung tissue damage and edema, respiratory failure and ultimately death. However, the exact mechanisms underlying pathological inflammation in sepsis are poorly understood, and thus the strategies to accelerate the resolution of sepsis are very limited. Studies in the proposal will test the novel hypothesis that pathogenic signaling caused by sepsis is the result of a macrophage-specific Fra-1/AP-1 restricted expression of anti- inflammatory A20, a crucial ubiquitin-editing enzyme that terminates uncontrolled activation of NF- κB and MAP kinase signaling. Our preliminary studies, using three pre-clinical models of sepsis, showed that Fra-1 as a crucial mediator of pro-inflammatory responses in sepsis. Endotoxemia (LPS)- and pseudomonas pneumonia-induced lung injury and inflammation are markedly lower in Fra-1-deficient mice than wild-type counterparts. Fra-1-deficient mice subjected to injurious dose of i.t bacterial endotoxin (LPS), showed an accelerated resolution of lung injury compared to wild-type mice. We found increased expression of Fra-1 largely in alveolar macrophages of cadaveric lungs infected with E. coli ex vivo and in mice exposed to LPS. Importantly, mice lacking Fra-1 in myeloid cells survived longer than wild-type mice from septic shock and polymicrobial sepsis. In preliminary studies, we found reduced levels of LPS-induced NF-κB activation and an increased expression of A20 in Fra-1-deficient macrophages. A20 haplo-sufficiency in humans and in mice is associated with heightened levels of systemic inflammation. We will address the specific hypothesis that in the settings of chronic or pathological sepsis Fra-1 activation secondary to microbial insults restricts optimal A20 expression and triggers pro-inflammatory response, thereby impairing the resolution of sepsis. We will use physiological and molecular approaches and tissue-specific knockout mice and preclinical models of sepsis to test this hypothesis. The specific aims of the proposal are to: 1) Determine the role and mechanisms of macrophage-specific Fra-1 signaling in mediating sustained lung injury in pseudomonas pneumonia and sepsis, and 2) Examine the mechanisms by which Fra-1 restricts A20 transcriptional induction by microbial insults in macrophages, and determine that Fra-1 restricted A20 signaling is a causative factor of persistent lung injury in sepsis. The proposed studies will identify novel insights and targets for therapies to accelerate lung injury repair in patients with pseudomonas pneumonia and sepsis.