Perturbation of Akt Signaling, Mitochondrial Potential, and ADP/ATP Ratio in Acidosis-Challenged Rat Cortical Astrocytes

King Chuen Wu, Ka Shun Cheng, Yu Wen Wang, Yuh Fung Chen, Kar Lok Wong, Tzu Hui Su, Paul Chan, Yuk Man Leung

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11 引文 斯高帕斯(Scopus)


Cells switch to anaerobic glycolysis when there is a lack of oxygen during brain ischemia. Extracellular pH thus drops and such acidosis causes neuronal cell death. The fate of astrocytes, mechanical, and functional partners of neurons, in acidosis is less studied. In this report, we investigated the signaling in acidosis-challenged rat cortical astrocytes and whether these signals were related to mitochondrial dysfunction and cell death. Exposure to acidic pH (6.8, 6.0) caused Ca2+ release and influx, p38 MAPK activation, and Akt inhibition. Mitochondrial membrane potential was hyperpolarized after astrocytes were exposed to acidic pH as soon as 1 h and lasted for 24 h. Such mitochondrial hyperpolarization was prevented by SC79 (an Akt activator) but not by SB203580 (a p38 inhibitor) nor by cytosolic Ca2+ chelation by BAPTA, suggesting that only the perturbation in Akt signaling was causally related to mitochondrial hyperpolarization. SC79, SB203580, and BAPTA did not prevent acidic pH-induced cell death. Acidic pH suppressed ROS production, thus ruling out the role of ROS in cytotoxicity. Interestingly, pH 6.8 caused an increase in ADP/ATP ratio and apoptosis; pH 6.0 caused a further increase in ADP/ATP ratio and necrosis. Therefore, astrocyte cell death in acidosis did not result from mitochondrial potential collapse; in case of acidosis at pH 6.0, necrosis might partly result from mitochondrial hyperpolarization and subsequent suppressed ATP production. J. Cell. Biochem. 118: 1108–1117, 2017.

頁(從 - 到)1108-1117
期刊Journal of Cellular Biochemistry
出版狀態已發佈 - 5月 1 2017

ASJC Scopus subject areas

  • 生物化學
  • 分子生物學
  • 細胞生物學


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