Astrocytic Poly(ADP-ribose) Polymerase-1 Activation Leads to Bioenergetic Depletion and Inhibition of Glutamate Uptake Capacity
Astrocytic Poly(ADP-ribose) Polymerase-1 Activation Leads to Bioenergetic Depletion and Inhibition of Glutamate Uptake Capacity
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DOI：
10.1002/glia.20936
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发表时间：
2010-03-01
期刊：
影响因子：
6.2
通讯作者：
Anderson, Christopher M.
中科院分区：
文献类型：
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作者：
Tang, Kim San;Suh, Sang Won;Anderson, Christopher M.
聚ADP-核糖聚合酶-1（PARP-1）是一种普遍存在的与基因组稳定性有关的核酶。过量的氧化性DNA链断裂导致PARP-1诱导的细胞NAD（+）、糖酵解速率、ATP水平的消耗，并最终导致细胞死亡。谷氨酸的神经传递受到ATP依赖性星形胶质细胞谷氨酸转运蛋白的严格控制，因此我们假设DNA损伤导致的星形胶质细胞PARP-1激活导致生物能量消耗和受损的谷氨酸摄取。DNA烷化剂N-甲基-N '-硝基-N-亚硝基胍（MNNG）激活PARP-1，导致培养的皮质星形胶质细胞存活率显著降低（EC 50 = 78.2 +/- 2.7 μ M）。HPLC显示MNNG诱导的NAD（+）（98%，4 h）、ATP（71%，4 h）、ADP（63%，4 h）和AMP（66%，4 h）的时间依赖性降低。最大[H-3]谷氨酸摄取速率（Vmax）也以与ATP消耗时间对应的方式下降，从对照细胞的19.3 +/- 2.8降至MNNG后4 h的2.1 +/- 0.8 nmol/min/mg蛋白。通过PARP-1基因缺失（直接表明PARP-1参与）和添加外源性NAD+（10 mM），生物能量消耗和谷氨酸摄取能力丧失均减弱。在混合神经元/星形胶质细胞培养物中，MNNG神经毒性部分由细胞外谷氨酸介导，并通过与PARP-1（-/-）星形胶质细胞共培养而降低，表明PARP-1对星形胶质细胞谷氨酸摄取的损害可充分提高谷氨酸水平，从而对邻近神经元产生受体介导的效应。总之，这些实验表明，PARP-1激活导致星形胶质细胞中总腺嘌呤核苷酸库的耗尽和神经保护性谷氨酸摄取能力的严重降低。(C)2009 Wiley-Liss，Inc.
Poly(ADP-ribose) polymerase-1 (PARP-1) is a ubiquitous nuclear enzyme involved in genomic stability. Excessive oxidative DNA strand breaks lead to PARP-1-induced depletion of cellular NAD(+), glycolytic rate, ATP levels, and eventual cell death. Glutamate neurotransmission is tightly controlled by ATP-dependent astrocytic glutamate transporters, and thus we hypothesized that astrocytic PARP-1 activation by DNA damage leads to bioenergetic depletion and compromised glutamate uptake. PARP-1 activation by the DNA alkylating agent, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), caused a significant reduction of cultured cortical astrocyte survival (EC50 = 78.2 +/- 2.7 mu M). HPLC revealed MNNG-induced time-dependent reductions in NAD(+) (98%, 4 h), ATP (71%, 4 h), ADP (63%, 4 h), and AMP (66%, 4 h). The maximal [H-3]glutamate uptake rate (V-max) also declined in a manner that corresponded temporally with ATP depletion, falling from 19.3 +/- 2.8 in control cells to 2.1 +/- 0.8 nmol/min/mg protein 4 h post-MNNG. Both bioenergetic depletion and loss of glutamate uptake capacity were attenuated by genetic deletion of PARP-1, directly indicating PARP-1 involvement, and by adding exogenous NAD+ (10 mM). In mixed neurons/astrocyte cultures, MNNG neurotoxicity was partially mediated by extracellular glutamate and was reduced by co-culture with PARP-1(-/-) astrocytes, suggesting that impairment of astrocytic glutamate uptake by PARP-1 can raise glutamate levels sufficiently to have receptor-mediated effects at neighboring neurons. Taken together, these experiments showed that PARP-1 activation leads to depletion of the total adenine nucleotide pool in astrocytes and severe reduction in neuroprotective glutamate uptake capacity. (C) 2009 Wiley-Liss, Inc.