Ying Weihai, Garnier Philippe, Swanson Raymond A
Department of Neurology, University of California at San Francisco and Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA.
Biochem Biophys Res Commun. 2003 Sep 5;308(4):809-13. doi: 10.1016/s0006-291x(03)01483-9.
Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear enzyme that is involved in DNA repair and activated by DNA damage. When activated, PARP-1 consumes NAD(+) to form ADP-ribose polymers on acceptor proteins. Extensive activation of PARP-1 leads to glycolytic blockade, energy failure, and cell death. These events have been postulated to result from NAD(+) depletion. Here, we used primary astrocyte cultures to directly test this proposal, utilizing the endogenous expression of connexin-43 hemichannels by astrocytes to manipulate intracellular NAD(+) concentrations. Activation of PARP-1 with the DNA alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) produced NAD(+) depletion, glycolytic blockade, and cell death. Cultures incubated in high (10mM) extracellular concentrations of NAD(+) after MNNG exposure showed normalization of intracellular NAD(+) concentrations. Repletion of intracellular NAD(+) in this manner completely restored glycolytic capacity and prevented cell death. These results suggest that NAD(+) depletion is the cause of glycolytic failure after PARP-1 activation.
聚（ADP - 核糖）聚合酶 -1（PARP -1）是一种核酶，参与DNA修复并由DNA损伤激活。激活后，PARP -1消耗NAD⁺以在受体蛋白上形成ADP - 核糖聚合物。PARP -1的广泛激活导致糖酵解阻滞、能量衰竭和细胞死亡。这些事件被认为是由NAD⁺耗竭引起的。在此，我们使用原代星形胶质细胞培养物直接测试这一假设，利用星形胶质细胞中连接蛋白43半通道的内源性表达来操纵细胞内NAD⁺浓度。用DNA烷化剂N - 甲基 - N'- 硝基 - N - 亚硝基胍（MNNG）激活PARP -1会导致NAD⁺耗竭、糖酵解阻滞和细胞死亡。MNNG暴露后在高（10mM）细胞外NAD⁺浓度中孵育的培养物显示细胞内NAD⁺浓度恢复正常。以这种方式补充细胞内NAD⁺可完全恢复糖酵解能力并防止细胞死亡。这些结果表明，NAD⁺耗竭是PARP -1激活后糖酵解衰竭的原因。
