Sun Meiling, Li Mei, Huang Qiao, Han Feng, Gu Jin-Hua, Xie Jiaming, Han Rong, Qin Zheng-Hong, Zhou Zhipeng
Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Soochow University School of Pharmaceutical Science, Suzhou 215123, China.
Institute of Pharmacology, Toxicology and Biochemical Pharmaceutics, Zhejiang University, Hangzhou 310058, China.
Neurochem Int. 2015 Jan;80:99-109. doi: 10.1016/j.neuint.2014.09.006. Epub 2014 Nov 4.
We previously found that TIGAR (TP53-induced glycolysis and apoptosis regulator) was upregulated in response to ischemia/reperfusion insult in a TP53-independent manner. The present study sought to investigate the regulatory mechanisms of TIGAR upregulation in animal and cellular models of stroke. The animal and cellular models of ischemia/reperfusion were produced by transient middle cerebral artery occlusion and reperfusion (tMCAO/R) and oxygen-glucose deprivation/reoxygenation (OGD/R), respectively. The expression of TIGAR protein in cortical tissues and hippocampal neuronal cell line HT22 cells or primary neurons was determined. Glucose, hormones and hydrogen peroxide (H2O2) were administered to mice via injection into the tail vein or lateral ventricle or directly added into cell culture medium. In mice subjected to tMCAO/R, the blood glucose level rapidly increased, peaking at 0.5 h and then declined. TIGAR protein was also significantly increased and then declined with a delayed time-course. The increase in TIGAR protein was blunted when blood glucose levels were controlled with insulin. However, administering glucose solution to mice or adding glucose to cell culture medium had no effect on TIGAR protein levels. In contrast adrenaline, hydrocortisone, glucagon and H2O2 significantly increased TIGAR protein expression, whereas insulin inhibited TIGAR expression. The transcription factor SP1 was induced by ischemia/reperfusion ahead of TIGAR upregulation. Inhibiting SP1 with mithramycin A or silencing SP1 with siRNA blocked the ischemia-induced TIGAR upregulation. These results suggest that ROS and hormones regulating blood glucose metabolism play a role in ischemia/reperfusion-induced TIGAR upregulation.
我们之前发现，TIGAR（TP53诱导的糖酵解和凋亡调节因子）以不依赖TP53的方式在缺血/再灌注损伤反应中上调。本研究旨在探讨在中风的动物和细胞模型中TIGAR上调的调控机制。缺血/再灌注的动物和细胞模型分别通过短暂大脑中动脉闭塞和再灌注（tMCAO/R）以及氧糖剥夺/复氧（OGD/R）产生。测定了皮质组织以及海马神经元细胞系HT22细胞或原代神经元中TIGAR蛋白的表达。通过尾静脉注射、侧脑室注射或直接添加到细胞培养基中，将葡萄糖、激素和过氧化氢（H2O2）给予小鼠。在接受tMCAO/R的小鼠中，血糖水平迅速升高，在0.5小时达到峰值，然后下降。TIGAR蛋白也显著增加，随后随时间延迟而下降。当用胰岛素控制血糖水平时，TIGAR蛋白的增加受到抑制。然而，给小鼠注射葡萄糖溶液或向细胞培养基中添加葡萄糖对TIGAR蛋白水平没有影响。相反，肾上腺素氢化可的松、胰高血糖素和H2O2显著增加TIGAR蛋白表达，而胰岛素抑制TIGAR表达。转录因子SP1在TIGAR上调之前被缺血/再灌注诱导。用丝裂霉素A抑制SP1或用siRNA沉默SP1可阻断缺血诱导的TIGAR上调。这些结果表明，调节血糖代谢的活性氧和激素在缺血/再灌注诱导的TIGAR上调中起作用。
