Hemodynamic Regulation of Thromboresistance

血栓抵抗的血流动力学调节

• 批准号: 7034034
• 负责人: JEFFREY J RADE
• 金额: $ 40.82万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7034034
• 关键词: Adenoviridae; atrium; biological signal transduction; biotechnology; cardiovascular disorder prevention; cardiovascular disorder therapy; chromatin immunoprecipitation; coronary occlusion /thrombosis; gene expression; gene therapy; genetic promoter element; heart failure; heart pharmacology; hemodynamics; human tissue; intracardiac pressure; pathologic process; shear stress; stretch receptors; thromboembolism; thrombomodulin; tissue /cell culture; transcription factor; transfection /expression vector; vascular endothelium

DESCRIPTION (provided by applicant): Thromboembolic events, including stroke, are a major cause of morbidity and mortality in patients with heart failure. Even with sinus rhythm, severe heart failure confers an annual stroke risk of 4%. While historically ascribed to blood stasis, dysfunction of the endocardial endothelium is a poorly studied and potentially important contributor to intracardiac thrombus formation. Thrombomodulin (TM), a key component of the protein C anticoagulant pathway, is critical to maintaining vascular thromboresistance. We recently found that TM expression by the left atrial endocardium in rats is significantly inhibited by acute pressure overload-induced heart failure and associated with increased local thrombin generation. In addition, we found that mechanical stretch is able to potently inhibit TM gene expression in culture rat endocardial cells. Based on these data, we hypothesize that pressure-induced stretch is an important and novel regulator of endocardial TM expression. The aims of this proposal are: 1) To determine the effects of heart failure on endocardial thromboresistance. Changes in endocardial TM expression and the functional consequences on thromboresistance will be determined in the cardiac chambers of rats subjected to acute and chronic pressure overload-induced heart failure. The effects of restoring endocardial TM expression in heart failure will be evaluated using a gene transfer strategy as well as pharmacologically. 2) To define critical hemodynamic stimuli and signaling pathways regulating TM expression. We will use endocardial cells placed into a novel ex vivo perfusion system to differentiate the effects static versus pulsatile stretch, to determine if shear modulates the effects of stretch and to define critical stretch-activated signaling pathways that mediate TM inhibition. 3) To determine the transcriptional mechanisms by which stretch regulates TM gene expression. We will use promoter-reporter constructs to localize stretch-responsive TM promoter elements and use chromatin immunoprecipitation and other molecular techniques to determine the effects of stretch on the expression and activity of transcription factors that regulate constitutive TM expression. Realization of the above specific aims will provide valuable insights into the pathobiology underlying thromboembolic complications associated with heart failure and may lead to novel therapeutic options for their prevention.

描述（由申请人提供）：血栓栓塞事件，包括中风，是心力衰竭患者发病和死亡的主要原因。即使有窦性心律，严重的心力衰竭也会导致每年 4% 的中风风险。虽然历史上将心内膜内皮功能障碍归因于血瘀，但研究很少，但它是心内血栓形成的潜在重要因素。血栓调节蛋白 (TM) 是蛋白 C 抗凝途径的关键成分，对于维持血管抗血栓能力至关重要。我们最近发现，大鼠左心房心内膜的 TM 表达受到急性压力超负荷诱发的心力衰竭的显着抑制，并与局部凝血酶生成增加相关。此外，我们发现机械拉伸能够有效抑制培养的大鼠心内膜细胞中的TM基因表达。基于这些数据，我们假设压力诱导的拉伸是心内膜 TM 表达的重要且新颖的调节因子。该提案的目的是： 1) 确定心力衰竭对心内膜血栓抵抗的影响。将在遭受急性和慢性压力超负荷诱发的心力衰竭的大鼠的心室中确定心内膜TM表达的变化以及对抗血栓性的功能影响。将使用基因转移策略以及药理学来评估恢复心力衰竭中心内膜 TM 表达的效果。 2) 定义调节TM表达的关键血流动力学刺激和信号通路。我们将使用置于新型离体灌注系统中的心内膜细胞来区分静态拉伸与脉动拉伸的效果，以确定剪切力是否调节拉伸的效果，并定义介导 TM 抑制的关键拉伸激活信号通路。 3) 确定拉伸调节TM基因表达的转录机制。我们将使用启动子-报告基因构建体来定位拉伸响应的TM启动子元件，并使用染色质免疫沉淀和其他分子技术来确定拉伸对调节组成型TM表达的转录因子的表达和活性的影响。上述具体目标的实现将为了解与心力衰竭相关的血栓栓塞并发症的病理学提供有价值的见解，并可能为预防这些并发症带来新的治疗选择。