Tauskela Joseph S, Brunette Eric, Monette Robert, Comas Tanya, Morley Paul
National Research Council, Institute for Biological Sciences, Montreal Road Campus, Bldg. M-54, Ottawa, ON, Canada K1A 0R6.
Am J Physiol Cell Physiol. 2003 Oct;285(4):C899-911. doi: 10.1152/ajpcell.00110.2003. Epub 2003 Jun 18.
Transient exposure of rat cortical cultures to nonlethal oxygen-glucose deprivation (OGD preconditioning) induces tolerance to otherwise lethal oxygen-glucose deprivation (OGD) or N-methyl-D-aspartate 24 h later. This study evaluates the role of cytosolic and mitochondrial Ca2+-dependent cellular signaling. Mechanistic findings are placed in context with other models of ischemic preconditioning or known neurotoxic pathways within cortical neurons. Tolerance to otherwise lethal OGD is suppressed by performing OGD preconditioning in the presence of the broad-scope catalytic antioxidants Mn(III)tetra(4-carboxyphenyl)porphyrin (MnTBAP) or Zn(II)tetra(4-carboxyphenyl)porphyrin [Zn(II)TBAP], but not by a less active analog, Mn(III)tetra(4-sulfonatophenyl)porphyrin, or a potent superoxide scavenger, Mn(III)tetra(N-ethyl-2-pyridyl)porphyrin chloride. Inhibitors of adenosine A1 receptors, nitric oxide synthase, mitogen-activated protein kinase, and poly(ADP-ribose) polymerase fail to suppress OGD preconditioning despite possible links with reactive oxygen species in other models of ischemic preconditioning. Preconditioning is suppressed by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), which has been ascribed elsewhere to inhibition of superoxide transport to the cytosol through mitochondrial anion channels. However, although it induces mitochondrial Ca2+ uptake, neuronal preconditioning is largely insensitive to mitochondrial uncoupling with carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone or 2,4-dinitrophenol. Un-couplers will prevent production of mitochondrial reactive oxygen species, implying nonmitochondrial targets by MnTBAP, Zn(II)TBAP, and DIDS. Emphasizing the importance of an increase in cytosolic Ca2+ during preconditioning, a Ca2+/calmodulin-dependent protein kinase II inhibitor, KN-62, suppresses development of subsequent tolerance. Summarizing, only those cellular transduction pathways that have the potential to be neurotoxic may be activated by preconditioning in cortical neurons. Finally, a marked decrease in extracellular glutamate is observed during otherwise lethal OGD in preconditioned cultures, suggesting that this end effector may represent a point of convergence across different preconditioning models.
将大鼠皮质培养物短暂暴露于非致死性氧糖剥夺（OGD预处理）可诱导其在24小时后对原本致死性的氧糖剥夺（OGD）或N-甲基-D-天冬氨酸产生耐受性。本研究评估了胞质和线粒体中钙依赖性细胞信号传导的作用。将机制研究结果与缺血预处理的其他模型或皮质神经元内已知的神经毒性途径相结合进行探讨。在存在广谱催化抗氧化剂锰（III）四（4-羧基苯基）卟啉（MnTBAP）或锌（II）四（4-羧基苯基）卟啉[锌（II）TBAP]的情况下进行OGD预处理，可抑制对原本致死性OGD的耐受性，但活性较低的类似物锰（III）四（4-磺基苯基）卟啉或强效超氧化物清除剂锰（III）四（N-乙基-2-吡啶基）卟啉氯化物则无此作用。尽管腺苷A1受体、一氧化氮合酶、丝裂原活化蛋白激酶和聚（ADP-核糖）聚合酶的抑制剂在其他缺血预处理模型中可能与活性氧有关，但它们并不能抑制OGD预处理。4,4'-二异硫氰基芪-2,2'-二磺酸（DIDS）可抑制预处理，在其他地方已将其归因于通过线粒体阴离子通道抑制超氧化物向胞质的转运。然而，尽管它可诱导线粒体对钙的摄取，但神经元预处理对羰基氰对-（三氟甲氧基）苯腙或2,4-二硝基苯酚引起的线粒体解偶联基本不敏感。解偶联剂可阻止线粒体活性氧的产生，这意味着MnTBAP、锌（II）TBAP和DIDS作用于非线粒体靶点。预处理过程中胞质钙的增加至关重要，钙/钙调蛋白依赖性蛋白激酶II抑制剂KN-62可抑制后续耐受性的形成。总之，在皮质神经元中，只有那些可能具有神经毒性的细胞转导途径可能被预处理激活。最后，在预处理培养物中进行原本致死性OGD期间，观察到细胞外谷氨酸显著减少，这表明这种终效应器可能代表了不同预处理模型的一个汇聚点。
