SD COBRE: MYOCYTE POLARITY AND SIGNAL TRANSDUCTION IN MYOCARDIAL INFARCTION

SD COBRE：心肌梗死中的心肌细胞极性和信号转导

• 批准号: 7720648
• 负责人: Faqian Li
• 金额: $ 27.32万
• 依托单位: UNIVERSITY OF SOUTH DAKOTA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7720648
• 关键词: Acute; Binding; Binding Sites; Breeding; CMV promoter; Cadherins; Cardiac Myocytes; Cell Nucleus; Cell membrane; Cells; Computer Retrieval of Information on Scientific Projects Database; Condition; Data; Doxycycline; FOS gene; Failure; Funding; Future; Gene Expression; Gene Expression Regulation; Glycogen Synthase Kinases; Grant; Growth; Heart Hypertrophy; Hypertrophy; Institution; LacZ Genes; Lead; Modeling; Mus; Muscle Cells; Myocardial Infarction; Myocardial Ischemia; Phenotype; Protein Overexpression; Protocols documentation; Pump; Rattus; Recruitment Activity; Regulation; Reporter; Research; Research Personnel; Resources; Sarcomeres; Series; Serine; Shapes; Signal Pathway; Signal Transduction; Signaling Molecule; Source; TCF Transcription Factor; Techniques; Threonine; Trans-Activators; Transgenic Mice; United States National Institutes of Health; beta catenin; gene therapy; genetic manipulation; promoter; size

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cardiac myocytes size increases through either longitudinal growth by series addition of sarcomeres or cross-sectional growth by parallel addition of sarcomeres. How cardiac myocytes incorporate sarcomeres is dependent on loading condition and resultant cytoskeletal changes. The activation of longitudinally-oriented cadherin-beta-catenin signaling pathways may recruit signal molecules to the polar plasma membrane and lead to series addition of sarcomeres, progressive cell lengthening and eventually pump failure. Glycogen synthase kinase-3beta (GSK-3beta)phosphorylates beta-catenin on serine and threonine, regulating cytoplasmic beta-catenin level and controlling gene expression. We hypothesize that activation of the beta-catenin signaling pathway by GSK-3beta inhibition triggers myocyte lengthening and eccentric hypertrophy. During the first year, we have focused on specific aims 1 and 3. These two aims are critical to the study of specific aim 2 and 4. In specific aim 1, we have conducted further studies on beta-catenin signaling during myocardial infarction. Our preliminary results have demonstrated that cytoplasmic free beta-catenin levels increase during acute myocardial ischemia. To further prove that beta-catenin signaling regulates gene regulation in cardiac myocytes, we have used a reporter mouse expressing lacZ under the control of a c-Fos minimal promoter and three Tcf binding sites. During beta-catenin signaling, free beta-catenin translocates to the nucleus and binds to TCF/LEF transcription factors resulting in increased LacZ expression. We continue to investigate myocyte polarity changes in a hypertensive rat model. Our data have showed that myocyte polarity changes during myocyte lengthening. The established protocols and techniques for myocyte polarity are ready to use in this proposal once mice with myocardial infarction are created. In specific aim 3, we have acquired transgenic mice conditionally overexpressing beta-catenin under the control of TA transactivator. These mice are currently bred with mice expressing TA transactivator under the control of either MHC or CMV promoter. We will induce gene expression with doxycycline and analyze phenotype once mice are available. These studies will further our understanding of myocyte shape and polarity regulation in cardiac hypertrophy and failure and identify key molecules involved in myocyte shape and polarity regulation for future genetic manipulation and gene therapy.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目和 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 心肌细胞大小通过任一纵向增加 通过连续添加肌节进行生长或通过平行添加肌节进行横截面生长。 心肌细胞如何整合肌节取决于负荷条件和由此产生的细胞骨架变化。纵向钙粘蛋白-β-连环蛋白信号通路的激活可能会将信号分子募集到极性质膜上，并导致肌节的连续添加、细胞逐渐延长并最终导致泵衰竭。糖原合酶激酶 3beta (GSK-3beta) 在丝氨酸和苏氨酸上磷酸化 β-连环蛋白，调节细胞质 β-连环蛋白水平并控制基因表达。我们假设 GSK-3β 抑制激活 β-连环蛋白信号通路会触发肌细胞延长和离心肥大。第一年，我们重点研究了具体目标1和3。这两个目标对于具体目标2和4的研究至关重要。在具体目标1中，我们对心肌梗死期间的β-catenin信号传导进行了进一步的研究。 我们的初步结果表明，急性心肌缺血期间细胞质游离β-连环蛋白水平增加。 为了进一步证明β-连环蛋白信号传导调节心肌细胞中的基因调控，我们使用了在c-Fos最小启动子和三个Tcf结合位点控制下表达lacZ的报告小鼠。 在 β-连环蛋白信号传导过程中，游离的 β-连环蛋白易位至细胞核并与 TCF/LEF 转录因子结合，导致 LacZ 表达增加。 我们继续研究高血压大鼠模型中肌细胞极性的变化。 我们的数据表明，肌细胞极性在肌细胞延长过程中发生变化。 一旦创建了患有心肌梗塞的小鼠，就可以在本提案中使用已建立的心肌细胞极性协议和技术。在具体目标3中，我们获得了在TA反式激活剂控制下条件性过度表达β-连环蛋白的转基因小鼠。 这些小鼠目前与在 MHC 或 CMV 启动子控制下表达 TA 反式激活蛋白的小鼠进行繁殖。 一旦小鼠可用，我们将用强力霉素诱导基因表达并分析表型。 这些研究将进一步加深我们对心脏肥大和衰竭中心肌细胞形状和极性调节的理解，并确定参与心肌细胞形状和极性调节的关键分子，以用于未来的基因操作和基因治疗。