Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.
Department of Cancer Biology, University of Toledo College of Medicine, Toledo, OH, USA.
FASEB J. 2021 May;35(5):e21373. doi: 10.1096/fj.202001636RRR.
Hyperactivation of PARP1 is known to be a major cause of necrotic cell death by depleting NAD /ATP pools during Ca overload which is associated with many ischemic diseases. However, little is known about how PARP1 hyperactivity is regulated during calcium overload. In this study we show that ATR kinase, well known for its role in DNA damage responses, suppresses ionomycin, glutamate, or quinolinic acid-induced necrotic death of cells including SH-SY5Y neuronal cells. We found that the inhibition of necrosis requires the kinase activity of ATR. Specifically, ATR binds to and phosphorylates PARP1 at Ser179 after the ionophore treatments. This site-specific phosphorylation inactivates PARP1, inhibiting ionophore-induced necrosis. Strikingly, all of this occurs in the absence of detectable DNA damage and signaling up to 8 hours after ionophore treatment. Furthermore, little AIF was released from mitochondria/cytoplasm for nuclear import, supporting the necrotic type of cell death in the early period of the treatments. Our results reveal a novel ATR-mediated anti-necrotic mechanism in the cellular stress response to calcium influx without DNA damage signaling.
PARP1 的过度激活已知是导致 Ca 超载时 NAD/ATP 池耗竭引起的坏死性细胞死亡的主要原因，而 Ca 超载与许多缺血性疾病有关。然而，关于 PARP1 过度激活在 Ca 超载期间如何被调节知之甚少。在这项研究中，我们表明，ATR 激酶，以其在 DNA 损伤反应中的作用而闻名，可抑制离子霉素、谷氨酸或喹啉酸诱导的包括 SH-SY5Y 神经元细胞在内的细胞的坏死性死亡。我们发现，抑制坏死需要 ATR 的激酶活性。具体而言，离子载体处理后，ATR 结合并在 PARP1 的 Ser179 位点磷酸化 PARP1。该位点特异性磷酸化使 PARP1失活，抑制离子载体诱导的坏死。引人注目的是，所有这些都发生在离子载体处理后长达 8 小时内没有检测到 DNA 损伤和信号的情况下。此外，线粒体/细胞质中很少有 AIF 释放到核内，支持治疗早期的坏死性细胞死亡类型。我们的结果揭示了一种新的 ATR 介导的抗坏死性机制，用于细胞对 Ca 内流的应激反应，而无需 DNA 损伤信号。
