Rac1 Stimulation in Adenosine-Induced Barrier Protection

Rac1 刺激腺苷诱导的屏障保护

• 批准号: 8376419
• 负责人: Alexander Verin
• 金额: $ 31.19万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8376419
• 关键词: Acute Lung Injury; Adenosine; Agonist; Alveolar; Attention; Attenuated; Blood Vessels; Cardiovascular Diseases; Coupling; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cytoskeletal Proteins; Data; Development; ERM protein; Endothelial Cells; Equilibrium; Event; Goals; Heterotrimeric GTP-Binding Proteins; In Vitro; Instruction; Investigation; Lead; Link; Liquid substance; Lung Inflammation; Lung diseases; Mediating; Modeling; Molecular; Mus; Permeability; Phosphorylation; Play; Process; Protein Dephosphorylation; Proteins; Publishing; Purinoceptor; Reagent; Receptor Activation; Role; Signal Pathway; Signal Transduction; Testing; Therapeutic; Tissues; Work; analog; attenuation; base; caldesmon; clinically relevant; ezrin; in vivo; moesin; mortality; myosin phosphatase; novel; protective effect; radixin protein; receptor coupling; repaired; response; rho

PROJECT SUMMARY (See instructions): Endothelial cells (EC) form a semi-permeable barrier between the interior space of blood vessels and the underlying tissues. In acute lung injury the EC barrier is weakened leading to increased permeability. Among the mechanisms regulating EC barrier function, Rho/VRad balance appears to be of major importance with RhoA activation being barrier-destructive and Rad activation is barrier-protective. This Project will elucidate the mechanisms underlying the barrier protective effects of Rad. We show that adenosine induces rapid increases in Rad activation and this correlates with a significant attenuation of LPS-induced EC permeability in vitro and in vivo. The ability of adenosine to enhance barrier function appears to be dependent on MLCP and correlates with increased levels of cAMP. However, the mechanistic links coupling increases in cAMP with the activation of Rad, MLCP stimulation and barrier protection are unknown. Thus, in this project we propose to investigate a novel mechanism of adenosine-induced EC barrier enhancement/protection via the coordinated activation, and interaction, of Rad and MLCP that is mediated by Epac1-Rap1- and protein kinase A (PKA)-signaling. We will also determine if the interactions between Rad and MYPT1 are involved in regulating MLCP activation and if the role of Epac1-Rap1 and PKA in this process. Finally, we will test the hypothesis that MLCP activation leads to EC barrier enhancement/protection via the dephosphorylation of the novel cytoskeletal proteins: the ERM proteins (ezrin, radixin, and moesin), and caldesmon. Thus, the overall objective of this project is to elucidate the molecular mechanisms through which Rad is involved in EC barrier enhancement/protection in response to adenosine. The detailed specific aims are: SA #1. To define the links between adenosine-induced Rad and MLCP activation and determine their role in EC barrier protection in vitro and in vivo SA #2. To define the involvement of MLCP cytoskeletal targets in Rad-induced EC barrier enhancement/protection in vitro and in vivo.

项目摘要（参见说明）： 内皮细胞（EC）在血管内部空间和皮下组织之间形成半透性屏障。在急性肺损伤中，EC 屏障减弱，导致通透性增加。在调节 EC 屏障功能的机制中，Rho/VRad 平衡似乎非常重要，RhoA 激活会破坏屏障，而 Rad 激活会保护屏障。该项目将阐明 Rad 屏障保护作用的机制。我们发现，腺苷会诱导 Rad 激活快速增加，这与体外和体内 LPS 诱导的 EC 通透性显着减弱相关。腺苷增强屏障功能的能力似乎依赖于 MLCP，并与 cAMP 水平的增加相关。然而，cAMP 与 Rad 激活、MLCP 刺激和屏障保护耦合增加的机制尚不清楚。 因此，在这个项目中，我们建议通过由 Epac1-Rap1- 和蛋白激酶 A (PKA) 信号介导的 Rad 和 MLCP 的协调激活和相互作用来研究腺苷诱导 EC 屏障增强/保护的新机制。我们还将确定 Rad 和 MYPT1 之间的相互作用是否参与调节 MLCP 激活，以及 Epac1-Rap1 和 PKA 在此过程中的作用。最后，我们将测试以下假设：MLCP 激活通过新型细胞骨架蛋白（ERM 蛋白（ezrin、radixin 和 moesin）和 caldesmon）的去磷酸化导致 EC 屏障增强/保护。因此，该项目的总体目标是阐明 Rad 参与 EC 屏障增强/保护以响应腺苷的分子机制。详细的具体目标是： SA＃1。确定腺苷诱导的 Rad 和 MLCP 激活之间的联系，并确定它们在体外和体内 EC 屏障保护中的作用 SA #2。明确 MLCP 细胞骨架靶标在体外和体内辐射诱导的 EC 屏障增强/保护中的作用。