mTOR may interact with PARP-1 to regulate visible light-induced parthanatos in photoreceptors
mTOR may interact with PARP-1 to regulate visible light-induced parthanatos in photoreceptors
复制标题
mTOR 可能与 PARP-1 相互作用来调节光感受器中可见光诱导的 parthanatos
DOI：
10.1186/s12964-019-0498-0
复制
发表时间：
2020-02-17
影响因子：
8.4
通讯作者：
Li，Guang-Yu
中科院分区：
文献类型：
--
作者：
Pan，Yi-Ran;Song，Jing-Yao;Li，Guang-Yu
背景过度光照是一种有害的环境因素，在视网膜变性的发病机制中起着关键作用。然而，光诱导的视网膜/感光细胞死亡的机制仍不清楚。雷帕霉素（mTOR）和聚（ADP-核糖）聚合酶-1（PARP-1）的哺乳动物/机制靶标已成为治疗许多神经退行性疾病的主要靶标。本研究的目的是阐明光诱导的感光细胞死亡的潜在机制，以及mTOR和PARP-1抑制对死亡的神经保护作用是否通过凋亡诱导因子（AIF）介导。方法碘化丙啶（PI）/Hoechst染色，慢病毒介导的短发夹RNA（shRNA），Western印迹分析，细胞组分分离，质粒瞬时转染，激光共聚焦显微镜，小鼠模型，视网膜电图（ERG），结果在光损伤的661 W细胞中，一种类似于死亡的死亡机制被评估，该细胞是一种永生化的光感受器细胞。Like细胞系表现出视锥光感受器细胞细胞和生物化学特征。死亡过程以PARP-1过度激活和AIF核转位为特征。PARP-1或AIF基因敲除对光损伤的光感受器具有明显的保护作用。更重要的是，在mTOR和PARP-1信号传导之间观察到串扰，并且mTOR可以通过中间因子sirtuin 1（SIRT 1）调节parthanatos。在体内也验证了parthanatos样损伤，其中PARP-1或mTOR抑制提供了针对光诱导损伤的显著神经保护，这通过结构和功能视网膜分析证明。总体而言，这些结果阐明了mTOR调节parthanatos死亡机制在光损伤的光感受器/视网膜，并可能促进视网膜变性diseases.ConclusionsOur结果表明，抑制mTOR/PARP-1轴对可见光诱导的parthanatos的光感受器产生保护作用的新的神经保护疗法的发展。这些保护作用是通过调节AIF的下游因子来实现的，而mTOR可能通过SIRT 1与PARP-1相互作用来调节parthanatos.Video Abstract图形摘要mTOR与PARP-1相互作用调节可见光诱导的parthanatos的示意图。由光暴露引起的增加的ROS穿透核膜并引起核DNA链断裂。PARP-1检测DNA断裂并合成PAR聚合物以启动消耗大量细胞NAD+的DNA修复系统。PAR聚合物的过度产生促使AIF从线粒体释放并易位到细胞核，这导致死亡。激活的mTOR可能通过SIRT 1与PARP-1相互作用，调节可见光诱导的死亡。
BackgroundExcessive light exposure is a detrimental environmental factor that plays a critical role in the pathogenesis of retinal degeneration. However, the mechanism of light-induced death of retina/photoreceptor cells remains unclear. The mammalian/mechanistic target of rapamycin (mTOR) and Poly (ADP-ribose) polymerase-1 (PARP-1) have become the primary targets for treating many neurodegenerative disorders. The aim of this study was to elucidate the mechanisms underlying light-induced photoreceptor cell death and whether the neuroprotective effects of mTOR and PARP-1 inhibition against death are mediated through apoptosis-inducing factor (AIF).MethodsPropidium iodide (PI)/Hoechst staining, lentiviral-mediated short hairpin RNA (shRNA), Western blot analysis, cellular fraction separation, plasmid transient transfection, laser confocal microscopy, a mice model, electroretinography (ERG), and hematoxylin-eosin (H & E) staining were employed to explore the mechanisms by which rapamycin/3-Aminobenzamide (3AB) exert neuroprotective effects of mTOR/PARP-1 inhibition in light-injured retinas.ResultsA parthanatos-like death mechanism was evaluated in light-injured 661 W cells that are an immortalized photoreceptor-like cell line that exhibit cellular and biochemical feature characteristics of cone photoreceptor cells. The death process featured over-activation of PARP-1 and AIF nuclear translocation. Either PARP-1 or AIF knockdown played a significantly protective role for light-damaged photoreceptors. More importantly, crosstalk was observed between mTOR and PARP-1 signaling and mTOR could have regulated parthanatos via the intermediate factor sirtuin 1 (SIRT1). The parthanatos-like injury was also verified in vivo, wherein either PARP-1 or mTOR inhibition provided significant neuroprotection against light-induced injury, which is evinced by both structural and functional retinal analysis. Overall, these results elucidate the mTOR-regulated parthanatos death mechanism in light-injured photoreceptors/retinas and may facilitate the development of novel neuroprotective therapies for retinal degeneration diseases.ConclusionsOur results demonstrate that inhibition of the mTOR/PARP-1 axis exerts protective effects on photoreceptors against visible-light–induced parthanatos. These protective effects are conducted by regulating the downstream factors of AIF, while mTOR possibly interacts with PARP-1 via SIRT1 to regulate parthanatos.Video AbstractGraphical AbstractSchematic diagram of mTOR interacting with PARP-1 to regulate visible light-induced parthanatos. Increased ROS caused by light exposure penetrates the nuclear membrane and causes nuclear DNA strand breaks. PARP-1 detects DNA breaks and synthesizes PAR polymers to initiate the DNA repair system that consumes a large amount of cellular NAD+. Over-production of PAR polymers prompts the release of AIF from the mitochondria and translocation to the nucleus, which leads to parthanatos. Activated mTOR may interact with PARP-1 via SIRT1 to regulate visible light-induced parthanatos.