The cGMP-dependent protein kinase pathway in platelets

血小板中 cGMP 依赖性蛋白激酶途径

• 批准号: 7819163
• 负责人: Xiaoping Du
• 金额: $ 1.95万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7819163
• 关键词: Adhesions; Agonist; Alpha Granule; Atherosclerosis; Blood Platelets; Blood Vessels; Chronic; Cyclic AMP; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Cytoplasmic Granules; Data; Development; Disease; Figs - dietary; Funding; Human; Injury; MAPK14 gene; Mediating; Mitogen-Activated Protein Kinases; Myocardial Infarction; Nitric Oxide; Nitric Oxide Donors; Nitric Oxide Synthase; Pathway interactions; Phosphatidylinositols; Phosphotransferases; Platelet Activation; Platelet aggregation; Play; Production; Protein Isoforms; Regulation; Research Personnel; Role; Signal Pathway; Signal Transduction; Site; Soluble Guanylate Cyclase; Stroke; Testing; Thrombosis; human NOS2A protein; human NOS3 protein; novel; programs

Platelet activation play critical roles in the development of thrombotic diseases such as heart attack and stroke. The roles of platelets in thrombosis involves two major aspects: Firstly, platelet adhesion, aggregation and secretion of granule contents are important in the development of atherosclerosis, which causes chronic vascular injury. Secondly, platelet activation at the site of vascular injury is critical in initiating arterial thrombosis. An intracellular secondary messenger molecule, cGMP, is synthesized during platelet activation. The role of cGMP in platelet activation has been controversial since the discovery of cGMP. It has been a prevailing concept in the past 30 years that cGMP, by activating the cGMP-dependent protein kinase (PKG), inhibits platelet activation. This concept, however, has been challenged by our recent finding that cGMPand PKG play a biphasic role in platelet activation, We show that cGMP plays a stimulatory role when low concentrations of cGMP is produced upon platelet agonist stimulation, but becomes inhibitory at high cGMP concentrations. During the last funding period, we have made significant progress in understanding the mechanisms of the biphasic roles of the cGMP pathway in platelet activation. We have found that the cGMP-PKG pathway plays a general role in stimulating platelet secretion and secretion-dependent platelet aggregation induced by most platelet agonists. We have obtained evidence supporting a new upstream signaling pathway of cGMP during platelet activation involving phosphoinositide 3-kinase, various forms of Akt and nitric oxide (NO) synthase. We have also obtained evidence supporting a novel downstreamsignaling mechanism of cGMP involving various isoforms of PKG and PKG-dependent sequentially activation of p38 and ERK mitogen-activated protein kinase pathways. These discoveries allow us to hypothesize a novel signaling pathwaythat stimulates platelet secretion. In this pathway, platelet agonists, by activating different isoforms of PI3K, Akt, NOS3,soluble guanylyl cyclase, and PKG, and via the p38 and ERK pathways, induce platelet secretion, which amplifies and stabilizes platelet aggregation. To test this hypothesis, we propose following specific aims: 1.To investigate the role of different Akt isoforms as upstream activators of the cGMP pathway during platelet activation. 2. To determine mechanisms of agonist-induced platelet NO production, its regulation, and its role in platelet secretion and aggregation. 3.To characterize the roles and the signaling mechanisms of different isoforms of PKGin platelet secretion and aggregation.

血小板激活在血栓形成疾病（如心脏病发作和中风）的发展中起关键作用。这 血小板在血栓形成中的作用涉及两个主要方面：首先，血小板粘附，聚集和分泌 颗粒含量在动脉粥样硬化的发展中很重要，该动脉粥样硬化会导致慢性血管损伤。第二， 血管损伤部位的血小板激活对于引发动脉血栓形成至关重要。细胞内次要 Messenger分子CGMP在血小板激活期间合成。 CGMP在血小板激活中的作用已经 自发现CGMP以来有争议。在过去30年中，CGMP是一个普遍的概念 激活CGMP依赖性蛋白激酶（PKG），抑制血小板激活。但是，这个概念一直是 由于我们最近的发现，CGMPAND PKG在血小板激活中起双相作用，我们表明CGMP 当血小板激动剂刺激产生低浓度的CGMP时，发挥刺激作用，但变成 在高CGMP浓度下抑制性。在最后的资金期间，我们在 了解CGMP途径在血小板激活中的双相作用的机制。我们发现 CGMP-PKG途径在刺激血小板分泌和分泌依赖性血小板聚集中起一般作用 由大多数血小板激动剂诱导。我们获得了支持CGMP新上游信号通路的证据 在涉及磷酸肌醇3-激酶的血小板活化期间，各种形式的Akt和一氧化氮（NO）合酶。我们 还获得了支持涉及各种同工型的CGMP的新型下游标志机制的证据 PKG和PKG依赖性p38和ERK促丝分裂原激活蛋白激酶途径的依次激活。这些 发现使我们能够假设一种新的信号通路刺激血小板分泌。在这条路中，血小板 激动剂，通过激活PI3K，AKT，NOS3，可溶性Guanylyl Cyclase和PKG的不同同工型，并通过p38和 ERK途径，诱导血小板分泌，它扩大并稳定血小板聚集。为了检验这一假设，我们 提出以下特定目的：1。研究不同Akt同工型作为CGMP上游激活剂的作用 血小板激活期间的途径。 2。确定激动剂诱导的血小板的机制，没有生产 调节及其在血小板分泌和聚集中的作用。 3.表征角色和信号传导机制 Pkgin血小板分泌和聚集的不同同工型。