Ventricular Remodeling in the Adapted Heart

适应心脏的心室重塑

• 批准号: 6776943
• 负责人: NILANJANA MAULIK
• 金额: $ 36.25万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6776943
• 关键词: SDS polyacrylamide gel electrophoresis; angiogenesis; apoptosis; cardiovascular stress test; gel mobility shift assay; genetic transcription; heart ventricle; immunocytochemistry; laboratory mouse; laboratory rat; mitogen activated protein kinase; myocardial infarction; myocardial ischemia /hypoxia; myocardium; nuclear factor kappa beta; polymerase chain reaction; protein biosynthesis; protein kinase C; regeneration; terminal nick end labeling; transcription factor; vascular endothelial growth factors; western blottings

DESCRIPTION (provided by applicant): Following myocardial infarction (MI), there is a progressive myocardial remodeling characterized by left ventricular (LV) dilation, contractile dysfunction, myocyte hypertrophy and increased matrix protein formation. The proposed project will examine the molecular mechanism(s) of hypoxic preconditioning (HP)- mediated myocardial remodeling in the infarcted heart by studying cardioprotective parameters at the transcriptional and protein level. We have established the optimal hypoxic preconditioning stimulus in rat MI model (10%O2/90%NS) to initiate capillary/arteriolar formation, increased blood flow and ventricular function in the myocardium. To establish the role of such HP in potentiating the signal transduction process for ventricular remodeling we will examine (i) the expression of VEGF and its tyrosine kinase receptors VEGFR1 (Flt-1) and VEGFR2 (FIk-1), expression and activity of protein kinase C, MAP Kinases-Aim I (ii) the expression and activity of iNOS/eNOS will be determined along with the transcriptional regulation of these factors by NFkB, Stat1-Aim 2 (iii) the extent of endothelial cell (EC) survival and the extent of necrosis/apoptosis, anti-apoptotic proteins Bcl-2, survivin expression, PI-3-Kinase activity, and the extent of AKT/BAD phosphorylation -Aim 3. Our rat MI model subjected to HP before LAD occlusion has significant advantage to study the molecular mechanism of myocardial remodeling over several months. An obligatory role of FIk-1, iNOS and eNOS in VEGF mediated signaling in myocardial angiogenesis/remodeling will be established by the use of Flk1, iNOS-/- and eNOS-/- knockout mice. The endothelial cell proliferation will be studied by BrdU incorporation assay, cardiomyocyte and endothelial cell apoptosis will be studied by double antibody staining, capillary and arteriolar density will be determined by labeling endothelial and smoothe muscle cells using anti-rat CD31 and anti-smooth muscle actin respectively. The results of this study will establish whether protein kinase-C, MAP kinases, eNOS/iNOS/NO are involved in VEGF and/or receptors (FIk-1/FIt-1) mediated myocardial regulation of HP induced remodeling in rat MI model. The results will provide new information required for new therapeutic strategies to protect the heart in patients with cardiac stress or coronary heart disease.

描述（由申请人提供）：心肌梗塞（MI）后，存在进行性心肌重塑，其特征在于左心室（LV）扩张、收缩功能障碍、肌细胞肥大和基质蛋白形成增加。 拟议的项目将通过研究转录和蛋白质水平的心脏保护参数来研究梗死心脏中缺氧预处理（HP）介导的心肌重塑的分子机制。 我们在大鼠心肌梗死模型中建立了最佳的低氧预处理刺激（10%O2/90%NS），以启动毛细血管/小动脉的形成，增加心肌中的血流量和心室功能。 为了确定此类 HP 在增强心室重塑信号转导过程中的作用，我们将检查 (i) VEGF 及其酪氨酸激酶受体 VEGFR1 (Flt-1) 和 VEGFR2 (FIk-1) 的表达、蛋白质的表达和活性激酶 C、MAP 激酶-Aim I (ii) iNOS/eNOS 的表达和活性将取决于 NFkB 对这些因子的转录调节， Stat1-Aim 2 (iii) 内皮细胞 (EC) 存活程度和坏死/凋亡程度、抗凋亡蛋白 Bcl-2、生存素表达、PI-3 激酶活性和 AKT/BAD 磷酸化程度-目标 3. 我们的大鼠 MI 模型在 LAD 闭塞之前进行 HP，对于研究几个月内心肌重塑的分子机制具有显着的优势。 FIk-1、iNOS 和 eNOS 在 VEGF 介导的心肌血管生成/重塑信号传导中的必然作用将通过使用 Flk1、iNOS-/- 和 eNOS-/- 敲除小鼠来确定。 通过BrdU掺入法研究内皮细胞增殖，通过双抗体染色研究心肌细胞和内皮细胞凋亡，通过使用抗大鼠CD31和抗平滑肌肌动蛋白标记内皮和平滑肌细胞来测定毛细血管和小动脉密度分别。 本研究的结果将确定蛋白激酶-C、MAP 激酶、eNOS/iNOS/NO 是否参与 VEGF 和/或受体 (FIk-1/FIt-1) 介导的 HP 诱导的大鼠 MI 模型重塑的心肌调节。 研究结果将为保护心脏应激或冠心病患者心脏的新治疗策略提供所需的新信息。