Microtubule Stability in Lung Endothelium

肺内皮微管稳定性

• 批准号: 8131404
• 负责人: Cristhiaan D. Ochoa Arenas
• 金额: $ 2.75万
• 依托单位: UNIVERSITY OF SOUTH ALABAMA
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8131404
• 关键词: Actins; Actomyosin; Acute Lung Injury; Address; Adenylate Cyclase; Adherens Junction; Adhesions; Adult Respiratory Distress Syndrome; Alveolar; Alzheimer' s Disease; Bacteria; Binding; Blood Vessels; Bundling; Cell Shape; Cell membrane; Cells; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cyclin-Dependent Kinase 5; Cytoskeleton; Data; Development; Edema; Endothelial Cells; Endothelium; Event; Exotoxins; Extracellular Matrix; Fiber; Gases; Glycogen Synthase Kinase 3; Goals; Inflammation; Inflammation Mediators; Inflammatory; Link; Lung; Maintenance; Membrane; Microtubule-Associated Proteins; Microtubules; Microvascular Permeability; Neurodegenerative Disorders; Neurons; Pathologic; Pathology; Permeability; Phosphorylation; Phosphotransferases; Physiological; Play; Prevention; Property; Protein Kinase; Proteins; Pseudomonas aeruginosa; Public Health; Pulmonary Circulation; Role; Sepsis; Serine; Severities; Signal Transduction; Stress Fibers; Testing; Toxic effect; Toxin; Traction; Vascular Permeabilities; casein kinase I; design; neurofibrillary tangle formation; receptor coupling; tau Proteins; tau phosphorylation; tau-1

DESCRIPTION (provided by applicant): Pulmonary microvascular endothelium forms a restrictive barrier to allow proper gas exchange. Inflammatory mediators and vascular permeability-increasing compounds cause retraction of cell borders and inter-endothelial gaps by reorganizing the endothelial cytoskeleton, cell-cell, and cell matrix interactions. Inflammatory mediators induce two critical changes in the endothelial cell cytoskeleton, including reorganization of the cortical actin rim into stress fibers, and disassembly and reorganization of microtubules. Despite their importance in control of endothelial cell shape, relatively little is known about intracellular signals that control microtubule assembly and disassembly. Microtubule-associated proteins regulate microtubule dynamics. Tau is a major neuronal microtubule-associated protein that promotes assembly, stability, and bundling of axonal microtubules. Tau hyper-phosphorylation reduces Tau microtubule binding-ability and causes neurofibrillary tangle formation, a pathologic severity marker of Alzheimer's disease. Protein Kinase A contributes to neurofibrillary tangle formation by phosphorylating Tau at serines 214, 262, and 356. Just recently, non-neuronal Tau has been found to regulate microtubule dynamics in endothelium. In endothelial cells, soluble adenylyl cyclase activity has been associated with Tau serine 214 phosphorylation and microtubule reorganization, and preliminary data suggest that Tau serine 214 phosphorylation releases Tau from endothelial microtubules. Interestingly, bacteria have evolved toxicity mechanisms that insert soluble adenylyl cyclases into endothelial cells and increase permeability. Since multiple different kinases can phosphorylate Tau, the mechanism by which adenylyl cyclase activity induces Tau hyperphosphorylation and endothelial barrier disruption is unknown. It is similarly unclear whether bacterial adenylyl cyclases induce endothelial hyperpermeability by a Tau-dependent mechanism. Therefore, the present application tests the overall hypothesis that bacterial adenylyl cyclase toxins induce Tau serine-214 phosphorylation that promotes microtubule disassembly and increases microvascular endothelial permeability. Specific aims will test the related hypotheses that: [1] Bacterial soluble adenylyl cyclase toxins activate PKA that phosphorylates Tau serine 214; and [2] Phosphorylation of Tau ser-214 is sufficient to disassemble microtubules and increase permeability. Completion of these studies will not only impact the understanding of endothelial permeability and bacterial-induced acute lung injury, but will also be significant in the field of neurodegenerative diseases. In the present proposal, we will rigorously test whether bacterial adenylyl cyclases generate a cAMP signal that results in phosphorylation of Tau ser-214 sufficient to depolymerize microtubules and increase endothelial permeability, and as PKA phosphorylation of Tau is a known pathophysiological event in Alzheimer's disease, our studies will resolve a putative mechanism responsible for PKA activation that results in Tau hyperphosphorylation. PUBLIC HEALTH RELEVANCE: Studies proposed in this application will address whether the microtubule-associated protein Tau plays an important role in maintaining lung vascular barrier integrity. This is very relevant to public health since these studies could help design new pharmacologic strategies to treat pathologies in which the lung vascular barrier is damaged, like acute respiratory distress syndrome and sepsis.

描述（由申请人提供）：肺微血管内皮形成限制性屏障以允许适当的气体交换。炎症介质和增加血管通透性的化合物通过重组内皮细胞骨架、细胞间和细胞基质相互作用，导致细胞边界和内皮间隙收缩。炎症介质诱导内皮细胞骨架发生两个关键变化，包括皮质肌动蛋白边缘重组为应力纤维，以及微管的分解和重组。尽管它们在控制内皮细胞形状方面很重要，但人们对控制微管组装和分解的细胞内信号知之甚少。微管相关蛋白调节微管动力学。 Tau 是一种主要的神经元微管相关蛋白，可促进轴突微管的组装、稳定性和成束。 Tau 过度磷酸化会降低 Tau 微管结合能力并导致神经原纤维缠结形成，这是阿尔茨海默病的病理严重程度标志。蛋白激酶 A 通过磷酸化丝氨酸 214、262 和 356 处的 Tau 来促进神经原纤维缠结的形成。最近，人们发现非神经元 Tau 可以调节内皮细胞的微管动力学。在内皮细胞中，可溶性腺苷酸环化酶活性与 Tau 丝氨酸 214 磷酸化和微管重组有关，初步数据表明 Tau 丝氨酸 214 磷酸化从内皮微管中释放 Tau。有趣的是，细菌已经进化出毒性机制，将可溶性腺苷酸环化酶插入内皮细胞并增加通透性。由于多种不同的激酶可以磷酸化 Tau，腺苷酸环化酶活性诱导 Tau 过度磷酸化和内皮屏障破坏的机制尚不清楚。同样尚不清楚细菌腺苷酸环化酶是否通过 Tau 依赖性机制诱导内皮细胞通透性过高。因此，本申请测试了细菌腺苷酸环化酶毒素诱导Tau丝氨酸214磷酸化的总体假设，该磷酸化促进微管解体并增加微血管内皮通透性。具体目标将检验以下相关假设： [1] 细菌可溶性腺苷酸环化酶毒素激活 PKA，磷酸化 Tau 丝氨酸 214； [2] Tau ser-214 的磷酸化足以分解微管并增加通透性。这些研究的完成不仅将影响对内皮通透性和细菌引起的急性肺损伤的理解，而且在神经退行性疾病领域也具有重要意义。在本提案中，我们将严格测试细菌腺苷酸环化酶是否产生cAMP信号，导致Tau ser-214磷酸化足以解聚微管并增加内皮通透性，并且由于Tau的PKA磷酸化是阿尔茨海默病中已知的病理生理学事件，我们的研究将解决 PKA 激活导致 Tau 过度磷酸化的假定机制。 公共健康相关性：本申请提出的研究将解决微管相关蛋白 Tau 是否在维持肺血管屏障完整性方面发挥重要作用。这与公共卫生非常相关，因为这些研究可以帮助设计新的药理学策略来治疗肺血管屏障受损的病理，如急性呼吸窘迫综合征和败血症。