Glucocorticoid induced G-CSF in lung inflammation

项目概述：糖皮质激素在炎症治疗中不可或缺，尽管它们不是 有效治疗严重哮喘和急性呼吸窘迫综合征中的嗜酸性肺部炎症。 我们的长期目标是开发新的糖皮质激素方案，提高疗效/风险比。的目标 这项提议是为了确定消除G-CSF信号传导是否会使糖皮质激素促进 中性粒细胞凋亡和改善肺部炎症。我们最近发现糖皮质激素 显著升高G-CSF，一种中性粒细胞促进细胞因子。G-CSF近年来被认为是一种 类固醇抵抗性肺部炎症的原因。我们假设糖皮质激素保护中性粒细胞 并通过刺激G-CSF增强中性粒细胞功能。G-CSF诱导由GR启动 和NF-κ B B p50相互作用。糖皮质激素诱导肺产生G-CSF 常驻细胞维持肺部炎症。阻断G-CSF信号传导将增加糖皮质激素的疗效 来避免嗜肺菌引起的肺部炎症为了验证我们的假设，我们将检查体外系统， 和体内。目的1中的研究将检验GR和p50相互作用介导G-CSF表达的假设 在肺部的各种细胞类型中。目的2中的研究将确定糖皮质激素诱导的G-CSF在 中性粒细胞存活、功能、运输和两种鼠模型中的嗜中性粒细胞肺炎。我们将使用 阻断G-CSF诱导的三种方法：使用G-CSFR缺失小鼠，抗G-CSF中和抗体， 两种天然的NF-κ B B抑制剂，我们已经确定能够抑制G-CSF诱导：姜黄素和 单性木兰我们的初步数据表明，糖皮质激素受体（GR）和NF-κ B B都是必需的 用于G-CSF诱导，并且p50而不是p65被募集到与GR相同的G-CSF启动子区域。 多个肺驻留细胞和浸润性白细胞产生G-CSF糖皮质激素刺激后。 使用中和抗体阻断G-CSF信号传导可消除糖皮质激素和IL-1β对 中性粒细胞凋亡。姜黄素联合糖皮质激素降低肺G-CSF， LPS肺损伤模型中的中性粒细胞数量。建议的研究将增进我们对 糖皮质激素诱导的G-CSF在嗜中性粒细胞显性糖皮质激素耐药疾病中的作用抑制G- 预期CSF信号传导增加糖皮质激素抑制气道损伤的能力， 中性粒细胞的活性和改善肺部炎症。

Project Summary: Glucocorticoids are indispensable in the treatment of inflammation although they are not effective in treating neutrophilic lung inflammation in severe asthma and acute respiratory distress syndrome. Our long-term goal is to develop new glucocorticoid regimens with improved efficacy/risk ratios. The goal of this proposal is to determine whether eliminating G-CSF signaling will allow glucocorticoids to promote neutrophil apoptosis and ameliorate lung inflammation. We have recently discovered that glucocorticoids significantly elevate G-CSF, a neutrophil promoting cytokine. G-CSF in recent years has been recognized as a cause of steroid-resistant lung inflammatory disorders. We hypothesize that glucocorticoids protect neutrophil from apoptosis and enhance neutrophil function via stimulation of G-CSF. G-CSF induction is initiated by GR and NF-B p50 interaction on the G-CSF promoter. Glucocorticoid-induction of G-CSF production in lung resident cells sustains lung inflammation. Blocking G-CSF signaling will increase the efficacy of glucocorticoids in circumventing neutrophil-driven lung inflammation. To test our hypotheses, we will examine systems in vitro and in vivo. Studies in Aim 1 will test the hypothesis that GR and p50 interactions mediate G-CSF expression in various cell types in lungs. Studies in Aim 2 will determine the role of glucocorticoid-induced G-CSF in neutrophil survival, functions, trafficking, and neutrophilic lung inflammation in two murine models. We will use three approaches to block G-CSF induction: using G-CSFR null mice, anti-G-CSF neutralizing antibodies, and two natural NF-B inhibitors that we have identified to be able to inhibit G-CSF-induction: curcumin and parthenolide. Our preliminary data indicate that both the glucocorticoid receptor (GR) and NF-B were required for G-CSF induction and p50, but not p65, was recruited to the same region of G-CSF promoter as GR. Multiple lung resident cells and infiltrating leukocytes produced G-CSF upon glucocorticoid stimulation. Blocking G-CSF signaling using neutralizing antibodies abolished glucocorticoid and IL-1β protection of neutrophils from undergoing apoptosis. Curcumin in combination with glucocorticoids reduced lung G-CSF and neutrophil numbers in an LPS lung injury model. The proposed studies will improve our understanding of the role of glucocorticoid-induced G-CSF in neutrophil-dominant glucocorticoid-resistant diseases. Inhibiting G- CSF signaling is anticipated to increase the ability of glucocorticoids to suppress the airway-damaging activities of neutrophils and ameliorate lung inflammation.