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。在缺血期间，成纤维细胞生长因子2触发的心脏保护通路(S)尚不清楚。然而，有证据表明，在许多类型的细胞中，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)和三磷酸腺苷敏感钾(KATP)通道来调节某些生物学功能，包括细胞生长、血管扩张和血管生成。所有这些信号通路在心脏保护中也被证明是重要的。将建立一种广泛的多学科方法，将结合不同的技术(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)，并将分子水平的遗传信息与整个器官/动物水平的生理信息相结合。为了确定成纤维细胞生长因子2介导的心脏保护的分子机制(S)，我们将评估已知的介导成纤维细胞生长因子2信号转导或参与心脏保护发展的蛋白激酶(PKC和MAPK)的活性模式。这将通过确定在野生型和FGF2转基因小鼠心脏缺血-再灌注损伤之前和期间这些途径中的哪些明显改变，并将这些分子/生化变化与缺血后心功能恢复和心肌梗死相关联来完成。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异构体(eNOS、iNOS和nNOS)，首次提供了小鼠心脏中这些变化的彻底特征。此外，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塞面积的影响，并与FGF2的生物学作用相关联。这些信号通路的整合将被评估，以确定激活是以并行方式还是以串联方式发生，以调节FGF2诱导的心脏保护。这项建议的结果将为FGF2诱导的心脏保护的分子和信号机制提供重要的新见解，并将促进新的药理和/或基因治疗策略的开发，以改善和增强易感心脏病患者的心脏抗缺血能力。

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.