Martín-Guerrero Sandra M, Muñoz-Gámez José A, Carrasco María-Carmen, Salmerón Javier, Martín-Estebané María, Cuadros Miguel A, Navascués Julio, Martín-Oliva David
Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Granada, Spain.
Instituto de Investigación Biomédica (ibsGranada), Hospital Universitario San Cecilio, Granada, Spain.
PLoS One. 2017 Oct 26;12(10):e0187130. doi: 10.1371/journal.pone.0187130. eCollection 2017.
Poly(ADP-ribose)polymerases (PARPs) are a family of NAD+ consuming enzymes that play a crucial role in many cellular processes, most clearly in maintaining genome integrity. Here, we present an extensive analysis of the alteration of mitochondrial morphology and the relationship to PARPs activity after oxidative stress using an in vitro model of human hepatic cells. The following outcomes were observed: reactive oxygen species (ROS) induced by oxidative treatment quickly stimulated PARPs activation, promoted changes in mitochondrial morphology associated with early mitochondrial fragmentation and energy dysfunction and finally triggered apoptotic cell death. Pharmacological treatment with specific PARP-1 (the major NAD+ consuming poly(ADP-ribose)polymerases) and PARP-1/PARP-2 inhibitors after the oxidant insult recovered normal mitochondrial morphology and, hence, increased the viability of human hepatic cells. As the PARP-1 and PARP-1/PARP-2 inhibitors achieved similar outcomes, we conclude that most of the PARPs effects were due to PARP-1 activation. NAD+ supplementation had similar effects to those of the PARPs inhibitors. Therefore, PARPs activation and the subsequent NAD+ depletion are crucial events in decreased cell survival (and increased apoptosis) in hepatic cells subjected to oxidative stress. These results suggest that the alterations in mitochondrial morphology and function seem to be related to NAD+ depletion, and show for the first time that PARPs inhibition abrogates mitochondrial fragmentation. In conclusion, the inhibition of PARPs may be a valuable therapeutic approach for treating liver diseases, by reducing the cell death associated with oxidative stress.
聚（ADP - 核糖）聚合酶（PARP）是一类消耗NAD⁺的酶家族，在许多细胞过程中发挥关键作用，在维持基因组完整性方面最为明显。在此，我们使用人肝细胞的体外模型，对氧化应激后线粒体形态的改变及其与PARP活性的关系进行了广泛分析。观察到以下结果：氧化处理诱导的活性氧（ROS）迅速刺激PARP激活，促进与早期线粒体碎片化和能量功能障碍相关的线粒体形态变化，最终引发凋亡性细胞死亡。在氧化损伤后用特异性PARP - 1（主要的消耗NAD⁺的聚（ADP - 核糖）聚合酶）和PARP - 1/PARP - 2抑制剂进行药物处理可恢复正常的线粒体形态，从而提高人肝细胞的活力。由于PARP - 1和PARP - 1/PARP - 2抑制剂取得了相似的结果，我们得出结论，大多数PARP的作用是由于PARP - 1激活所致。补充NAD⁺与PARP抑制剂具有相似的效果。因此，PARP激活及随后的NAD⁺消耗是氧化应激下人肝细胞中细胞存活降低（及凋亡增加）的关键事件。这些结果表明，线粒体形态和功能的改变似乎与NAD⁺消耗有关，并首次表明PARP抑制可消除线粒体碎片化。总之，抑制PARP可能是一种通过减少与氧化应激相关的细胞死亡来治疗肝病的有价值的治疗方法。
