Ischemic preconditioning and heat shock activate Akt via a focal adhesion kinase-mediated pathway in Langendorff-perfused adult rat hearts.
Ischemic preconditioning and heat shock activate Akt via a focal adhesion kinase-mediated pathway in Langendorff-perfused adult rat hearts.
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DOI：
10.1152/ajpheart.00613.2009
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Hongguang Wei;R. V. Vander Heide
中科院分区：
文献类型：
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作者：
Hongguang Wei;R. V. Vander Heide
热应激（HS）诱导的心脏保护与新生大鼠心室肌细胞（nrvm）的局灶黏附激酶（FAK）和蛋白激酶B （Akt）的激活有关，这表明应激诱导的存活途径激活可能在保护完整心脏免受不可逆损伤中起重要作用。本研究的目的是：1)研究HS和缺血预处理（ischemic preconditioning， IP）在完整心脏中激活的亚细胞信号通路；2)确定HS和IP在培养的nrvm中是否激活了类似HS激活的综合生存通路；3)确定HS和IP是否减少了灌注完整心脏的致死细胞损伤。在Langendorff模式下灌注的成年大鼠心脏在全动物HS后24小时或按照标准IP协议进行25分钟的全脑缺血和30分钟的再灌注（I/R）。心肌信号转导采用Western blot分析，细胞死亡采用乳酸脱氢酶释放到灌注液，光镜证实。与nrvm类似，在I/R前24小时对全动物进行HS，使FAK酪氨酸-397和蛋白激酶B （Akt）的磷酸化增加，从而保护细胞免于死亡。使用IP作为心肌应激也导致FAK和Akt的磷酸化/活化增加，并导致I/R的成年灌注大鼠心脏细胞死亡减少。综上所述，1)全动物HS引起的心肌应激激活了整个心脏组织中基于细胞骨骼的存活信号通路，减轻了致死性I/R损伤；2)IP激活了相同的应激诱导存活信号通路，并且激活与IP对致死性I/R损伤的心脏保护作用相关。
Heat stress (HS)-induced cardioprotection is associated with the activation of focal adhesion kinase (FAK) and protein kinase B (Akt) in neonatal rat ventricular myocytes (NRVMs), suggesting that stress-induced activation of survival pathways may be important in protecting intact hearts from irreversible injury. The purposes of this study were 1) to examine the subcellular signaling pathways activated by HS and ischemic preconditioning (IP) in intact hearts, 2) to determine whether HS and IP activate an integrated survival pathway similar to that activated by HS in cultured NRVMs, and 3) to determine whether HS and IP reduce lethal cell injury in perfused intact hearts. Adult rat hearts perfused in the Langendorff mode were subjected to 25 min of global ischemia and 30 min of reperfusion (I/R) either 24 h after whole animal HS or following a standard IP protocol. Myocardial signaling was analyzed using Western blot analysis, whereas cell death was assayed by measuring lactate dehydrogenase release into the perfusate and confirmed by light microscopy. Similar to NRVMs, HS performed in the whole animal 24 h before I/R increased phosphorylation of FAK at tyrosine-397 and protein kinase B (Akt) and resulted in protection from cell death. Using IP as a myocardial stress also resulted in an increased phosphorylation/activation of both FAK and Akt and resulted in reduced cell death in adult perfused rat hearts subjected to I/R. In conclusion, 1) myocardial stress caused by whole animal HS activates cytoskeletal-based survival signaling pathways in whole heart tissue and reduces lethal I/R injury and 2) IP activates the same stress-induced survival pathway and the activation correlates with the well-known cardioprotective effect of IP on lethal I/R injury.