Microtubule-associated regulation of acute lung injury

 描述（由申请人提供）：肺部炎症和内皮通透性的改变在急性肺损伤（ALI）和急性呼吸窘迫综合征（ARDS）的病理生理学中起主要作用，这些疾病与高死亡率相关。目前治疗的低效率可以部分地通过专注于旨在预防ALI发作的药物治疗来解释，而平息炎症激活和内皮屏障功能障碍的内源性反馈机制，尽管临床上更相关，但仍然知之甚少。 我们在上一周期的研究确定了微管外周网络在控制肺内皮屏障功能中的新作用。我们发现，通过屏障增强激动剂如肝细胞生长因子刺激微管外周生长，促进Rac GTP酶依赖性信号传导并减弱Rho GTP酶依赖性信号传导，从而导致血管渗漏的下调。我们定义了一个新的范例的双重调控的Rac和Rho途径的微管相关的鸟嘌呤核苷酸交换因子Asef和GEF-H1，并证明了至关重要的作用的Rac Rho串扰和控制内皮细胞通透性的机制中的微管。然而，整个机制的微管依赖性调控的发病和解决的ALI，特别是，微管依赖性调节炎症级联反应，仍然知之甚少。 在筛选与对照和炎症肺内皮中微管相关的潜在信号蛋白的过程中，我们发现了炎症信号负调节因子SOCS 1与微管组分的相关性。这一意外发现表明微管细胞骨架与内皮炎症和炎症诱导的渗透性控制之间存在新的联系。目前，微管在调节内皮屏障对细菌壁化合物、细胞因子等的反应中的作用，仍然是个未知数我们假设，细胞反馈机制调节细胞炎症反应的关键需要微管辅助的SOCS 1靶向膜下区室，在那里它与其细胞因子受体和TLR相关的蛋白质靶点相互作用。使用细胞，离体和体内模型的LPS诱导的ALI，本申请将表征调节LPS诱导的炎症的SOCS 1，调查参与的微管控制的SOCS 1抗炎功能，并将确定积极的微管辅助的SOCS 1运输和亚膜靶向的分子机制。本项目的结果将描述调节肺屏障功能障碍和炎症的新型微管依赖性机制，这可能导致发现一组新的用于治疗ALI/ARDS的药理学分子。

 DESCRIPTION (provided by applicant): Lung inflammation and alterations in endothelial permeability play a major role in the pathophysiology of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), the conditions associated with high mortality rates. Low efficiency of current therapies may be explained in part by focus on drug treatments aimed at prevention of the onset of ALI, while endogenous feedback mechanisms which subside inflammatory activation and endothelial barrier dysfunction, although much more clinically relevant, remain poorly understood. Our studies in the previous cycle identified a novel role of microtubule peripheral network in the control of lung endothelial barrier function. We discovered that stimulation of microtubule peripheral growth by barrier enhancing agonists, such as hepatocyte growth factor, promoted Rac GTPase-dependent and attenuated Rho GTPase-dependent signaling, thus leading to downregulation of vascular leak. We defined a novel paradigm of dual regulation of Rac and Rho pathways by microtubule-associated guanine nucleotide exchange factors Asef and GEF-H1 and demonstrated essential role of the microtubules in the mechanisms of Rac-Rho crosstalk and control of endothelial permeability. However, the entire mechanism of microtubule-dependent regulation of onset and resolution of ALI, and specifically, microtubule-dependent modulation of inflammatory cascades, remains poorly understood. During the screening of potential signaling proteins associated with the microtubules in control and inflamed pulmonary endothelium, we discovered an association of a negative regulator of inflammatory signaling, SOCS1, with the microtubule fraction. This serendipity finding suggested a novel link between the microtubule cytoskeleton and control of endothelial inflammation and inflammation-induced permeability. Currently, a role of microtubules in the modulation of endothelial barrier response to bacterial wall compounds, cytokines, etc., remains virtually unknown. We hypothesize that cellular feedback mechanisms modulating cell inflammatory response critically require microtubule-assisted SOCS1 targeting to the submembrane compartment, where it interacts with its cytokine receptor- and TLR-associated protein targets. Using cell, ex vivo, and in vivo models of LPS-induced ALI this application will characterize regulation of LPS-induced inflammation by SOCS1, investigate involvement of microtubules in control of SOCS1 anti-inflammatory function, and will identify molecular mechanisms of active microtubule-assisted SOCS1 transport and submembrane targeting. The results of this project will delineate novel microtubule-dependent mechanisms regulating lung barrier dysfunction and inflammation, which may lead to discovery of a new group of pharmacological molecules for the treatment of ALI/ARDS.