CARDIAC HYPERTROPHY INDUCED METABOLIC GENE REGULATION

心脏肥大和充血性心力衰竭是重要的原因 美国的发病率和死亡率。 人心 在病理生理刺激下发生肥大性生长 例如慢性高血压和瓣膜疾病。 的过渡 正常到肥厚的心室以特征性分子标记 表型变化，包括能量代谢基因的转换 主要是脂肪酸β-氧化的监管计划（粮农组织） 到更有效的氧酵解，一个重新激活的胎儿 新陈代谢. 对肥大信号通路知之甚少 将细胞外刺激与转录调控联系起来。 广大 该建议的目标是描述分子调节信号 这最终导致粮农组织在 肥厚 该提案的目的是：i） 脂肪酸β-氧化基因转录的改变 大鼠新生心肌细胞肥大，并描绘 特异性顺式作用元件介导利用北方 蛋白质印迹分析、RNA酶保护和瞬时基因转移 粮农组织酶基因启动子的研究; ii）确定特定的 转录调节因子，其结合到细胞中的应答元件。 心肌细胞肥大过程中β-氧化基因的启动子 利用电泳迁移率变动分析，共转染，北方 和Western印迹分析、RNA酶保护和免疫荧光; iii）确定调节剂的活性是否增加 在通过磷酸化事件的肥大过程中，利用体外和体内 体内磷酸化研究，已知信号转导的抑制剂 级联反应和磷酸化位点突变，重点是 丝裂原活化蛋白激酶途径。 长期目标将是 以确定胎儿代谢基因程序的重新激活 和/或脂肪酸β-氧化的下调导致 适应不良的肥大表型，从而促进过渡到 心衰 如果是这样，上述研究将确定 治疗干预的潜在目标，旨在延缓或 甚至可以防止发展为终末期心肌病

Cardiac hypertrophy and congestive heart failure are significant causes of morbidity and mortality in the United States. The human heart undergoes hypertrophic growth in response to pathophysiologic stimuli such as chronic hypertension and valvular disease. The transition from normal to hypertrophied ventricle is marked by characteristic molecular phenotypic changes, including a switch in the energy metabolic gene regulatory program from predominantly fatty acid beta-oxidation (FAO) to the more oxygen-efficient glycolysis, a reactivation of fetal metabolism. Little is known about the hypertrophy signaling pathway linked extracellular stimulus to transcriptional regulation. The broad goals of this proposal are to delineate the molecular regulatory signals which ultimately contribute to down-regulation of FAO during hypertrophy. This proposal is specifically designed to i) characterize alterations in fatty acid beta-oxidation gene transcription in cultured rat neonatal cardiocytes undergoing hypertrophy and to delineate the specific cis-acting elements mediating that response utilizing Northern and Western blot analysis, RNase protection, and transient gene transfer studies with FAO enzyme gene promoters; ii) identify the specific transcriptional regulators that bind to the responsive elements in the promoters of beta-oxidation genes during cardiocyte hypertrophy utilizing electrophoretic mobility shift assay, cotransfection, Northern and Western blot analysis, RNase protection, and immunofluorescence; iii) determine whether the activity of the regulators are increased during hypertrophy by phosphorylation events utilizing in vitro and in vivo phosphorylation studies, inhibitors of known signal transduction cascades, and phosphorylation site mutations with emphasis on the mitogen-activated protein kinase pathway. The longterm goals will be to determine whether reactivation of this fetal metabolic gene program and/or downregulation of fatty acid beta-oxidation leads to a maladaptive hypertrophied phenotype and thus promotes the transition to heart failure. If so, the studies outlined above will have identified potential targets for therapeutic interventions aimed at delaying or even preventing progression to end-stage cardiomyopathy.