Signaling mechanisms of FGF2-induced cardioprotection

描述（由申请人提供）：本提案的总体目标是研究成纤维细胞生长因子-2 （FGF2）心脏保护作用的信号机制。FGF2在缺血时触发心脏保护的途径尚不清楚。然而，有证据表明，在许多细胞类型中，FGF2可以通过蛋白激酶C （PKC）、丝裂原活化蛋白激酶（MAPK）或一氧化氮（NO）和atp敏感钾（KATP）通道发出信号，介导某些生物学功能，包括细胞生长、血管舒张和血管生成。所有这些信号通路也被证明在心脏保护中很重要。将建立一个广泛的多学科方法，将结合各种技术（综合生理学，分子遗传学，基因靶向/转基因小鼠模型和药理学），并将整合分子水平的遗传信息和整个器官/动物水平的生理信息。为了确定FGF2介导的心脏保护的分子机制，我们将评估已知介导FGF2信号传导或与心脏保护发展有关的蛋白激酶（PKC和MAPK）的活性模式。这将通过确定野生型和FGF2转基因小鼠心脏在缺血再灌注损伤之前和期间哪些途径显着改变，并将这些分子/生化变化与心肌功能缺血恢复和心肌梗死相关来完成。FGF2的慢性心脏表达对一氧化氮合酶（NOS） mRNA、蛋白质、酶活性和细胞分布的影响将被系统地定义为所有三种亚型（eNOS、iNOS和nNOS），首次提供小鼠心脏中这些变化的全面表征。此外，我们还将研究PKC、MAPK、NOS和KATP通道的药理抑制剂对缺血后心功能恢复和梗死面积的影响，并将其与FGF2的生物学作用联系起来。这些信号通路的整合将被评估，以确定激活是否以并行或串行方式发生，以调节fgf2诱导的心脏保护。本研究结果将为fgf2诱导心脏保护的分子和信号机制提供重要的新见解，并有助于开发新的药物和/或基因治疗策略，以改善和增强心脏易感患者对缺血的心脏抵抗。

DESCRIPTION (provided by applicant): The overall objective of this proposal is to investigate the signaling mechanisms underlying the cardioprotective effect of fibroblast growth factor-2 (FGF2). The pathway(s) triggered by FGF2 to elicit protection in the heart during ischemia is unknown. However, evidence indicates that in many cell types, FGF2 can signal through protein kinase C (PKC), mitogen-activated protein kinase (MAPK), or nitric oxide (NO) and ATP-sensitive potassium (KATP) channels to mediate certain biological functions including cellular growth, vasodilation, and angiogenesis. All of these signaling pathways have also been shown to be important in cardioprotection. A broad multidisciplinary approach will be established that will combine diverse techniques (integrative physiology, molecular genetics, gene-targeted/transgenic mouse models, and pharmacology) and will integrate genetic information at the molecular level with physiological information at the whole organ/animal level. To ascertain the molecular mechanism(s) for FGF2-mediated cardioprotection, we will assess the patterns in activity of protein kinases (PKC and MAPK) that are either known to mediate FGF2 signaling or have been implicated in the development of cardioprotection. This will be done by determining which of these pathways is markedly altered prior to and during ischemia-reperfusion injury in wildtype and FGF2 transgenic mouse hearts and correlating these molecular/biochemical changes with post ischemic recovery of cardiac function and myocardial infarction. The effects of chronic cardiac expression of FGF2 upon nitric oxide synthase (NOS) mRNA, protein, enzymatic activity, and cellular distribution will be systematically defined for all three isoforms (eNOS, iNOS, and nNOS), providing for the first time a thorough characterization of these changes in the mouse heart. Furthermore, the effect of pharmacological inhibitors of PKC, MAPK, NOS, and KATP channels, on post-ischemic recovery of cardiac function and infarct size will be investigated and correlated with the biological actions of FGF2. Integration of these signaling pathways will be evaluted to determine whether activation occurs in a parallel or serial fashion to modulate FGF2-induced cardioprotection. The results from this proposal will provide important new insights into molecular and signaling mechanisms of FGF2-induced cardioprotection and should facilitate the development of novel pharmacological and/or gene therapeutic strategies that improve and enhance cardiac resistance to ischemia in susceptible cardiac patients.