ATP in Lung Endothelial Barrier Enhancement

肺内皮屏障增强中的 ATP

• 批准号: 7435762
• 负责人: ALEXANDER D VERIN
• 金额: $ 35.68万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7435762
• 关键词: Acute Lung Injury; Adhesions; Adhesives; Agonist; Apoptosis; Attenuated; Biochemical; Blood Platelets; Blood Vessels; Cell Wall; Cells; Complex; Condition; Cyclic AMP-Dependent Protein Kinases; Cytoskeletal Proteins; Data; Disruption; Dose; Electrical Resistance; Endothelial Cells; Endothelium; Enzymes; Extracellular Fluid; F-Actin; Family; Figs - dietary; Functional disorder; GTP-Binding Proteins; Homeostasis; Hour; Inflammatory; Investigation; Lead; Leukocytes; Link; Liquid substance; Lung; Lung diseases; Mediating; Mediator of activation protein; Mitogen-Activated Protein Kinases; Modeling; Molecular; Mus; Myosin ATPase; Myosin Light Chains; Pathway interactions; Permeability; Phosphoric Monoester Hydrolases; Phosphorylation; Physiological; Principal Investigator; Process; Protein Dephosphorylation; Proteins; Publishing; Pulmonary artery structure; Regulation; Role; Signal Pathway; Signal Transduction; Smooth Muscle; Source; Stress Fibers; Thrombin; Tissues; Vascular Permeabilities; Work; caldesmon; cell growth; clinically relevant; extracellular; ezrin; injury prevention; lung injury; migration; novel; programs; protective effect; protein activation; radixin protein; receptor coupling; response

ROVIDED. Endothelial cell (EC) barrier dysfunction, a prominent feature of acute lung injury (ALT), is tightly linked to cytoskeletal remodeling, which leads to the disruption of cell-cell contacts and includes activation of contraction initiated by myosin light chain (MLC)phosphorylation followed by F-actin stress fiber formation and formation of paracellular gaps. Little is known about processes which determine barrier enhancement or protection; however, our published data implicate a critical role for cytoskeletal dynamics in this response. Extracellular ATP is an important vascular mediator, which elicits cellular effects on EC mainly through P2Y family receptors coupled to specific trimeric G- proteins. Our novel findings indicate that ATP at physiologically relevant concentrations produces rapid, sustained and dose-dependent increases in transendothelial electrical resistance (TER), indicating profound barrier enhancement and potently reversed barrier dysfunction elicited by the edemagenic agent, thrombin. Specific depletion of a subunits of Gq and Gi2 significantly attenuated ATP-induced increase in TER indicating the involvement of these G-proteins inATP- induced EC barrier enhancement. The ATP-induced increase in TER is tightly linked to an increase in myosin-associated phosphatase (PPase) 1 (MLCP) activity. Inhibition of PPase 1 abolished the ATP-induced increase in TER and lead to phosphorylation of several cytoskeletal targets includingMLC, ezrin/radixin/moezin (ERM) and caldesmon suggesting that dephosphorylation of these proteins may be involved in the barrier-enhancing effect of ATP. In addition, protein kinase A (PKA) inhibition attenuates both ATP-induced increases in TER and phosphorylation of vasolidator- stimulated protein (VASP), which in the phosphorylated form inhibits stress fiber formation supporting the involvement of the PKA/VASP pathway in ATP-induced EC barrier enhancement. Our working hypothesis is that ATP-induced EC barrier enhancement and cytoskeletal remodeling is dependent, at least in part, upon activation of specific P2Y/G protein complexes followed by coordinated activation of MLCP and PKA signaling. SA#1will define the role of specific P2Y/G-protein complexes in the activation of MLCP- and PKA-dependent signaling. SA#2 will define the involvement of MLCP and its cytoskeletal targets in ATP-induced EC barrier enhancement. SA #3 will explore the molecular mechanisms by which PKA activity is involved in ATP-induced EC barrier enhancement focusing on VASP and MLCP as potential PKA targets. SA#4 will characterize the potential barrier-protective effects of ATP in murine models of ALL These studies will provide an understanding of the novel signaling pathways involved in ATP-induced lung EC barrier enhancement and promise new directions and targets for treatment of lung disorders.

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