Kuo Eva YuHua, Chang Hsueh-Ling, Lin Shu-Tseng, Lee Tse-Min
Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan.
Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University, Kaohsiung, Taiwan.
Front Plant Sci. 2020 Jun 10;11:772. doi: 10.3389/fpls.2020.00772. eCollection 2020.
Autophagy plays a role in regulating important cellular functions in response to stress conditions. The role of nitric oxide (NO) in the regulation of autophagy in has been not studied. Illumination of cells under a high light (HL, 1,600 μmol m s) condition induced a NO burst through NO synthase- and nitrate reductase-independent routes, and cell death. The abundance of CrATG8 protein, an autophagy marker of , increased after HL illumination along with a linear increase in the transcript abundance of autophagy-associated genes (CrVPS34, CrATG1, CrATG3, CrATG4, CrATG6, CrATG7, CrATG8, and CrATG12), which were suppressed in the presence of an NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO). The cells were treated with NO donors, -nitroso--acetyl-penicillamine, and -nitrosoglutathione, under a normal light (50 μmol m s) condition to elucidate the role of NO in autophagy activation and cell death. Treatment with 0.05 mM or 0.1 mM NO donors increased the abundance of ATG8 protein and CrATG transcripts, which were suppressed in the presence of cPTIO. Moreover, treatment with 0.05 mM NO donors did not affect cell viability, while 0.1 mM NO donors elicited a transient decrease in cell growth and death that recovered after 12 h. The transient effect could be prevented by the presence of cPTIO. However, treatment with 1 mM HO and 0.1 mM NO donors enhanced autophagy induction and resulted in cell death after 24 h. The interaction of HO and NO can be prevented by cPTIO treatment. This implies that NO is critical for the interaction of HO and NO that induces cell death and autophagy. Furthermore, exposure to 0.1 mM NO donors under a non-lethal HL condition (750 μmol m s) evoked autophagy and cell death. In conclusion, the present findings demonstrated that the NO-mediated autophagy pathway is activated in under lethal high intensity illumination and may interact with HO for HL-induced cell death. The relationships between autophagy and cell death are discussed.
自噬在应激条件下调节重要细胞功能中发挥作用。一氧化氮（NO）在[具体生物名称未给出]自噬调节中的作用尚未得到研究。在高光（HL，1600 μmol m⁻² s⁻¹）条件下照射[具体生物名称未给出]细胞，通过不依赖于一氧化氮合酶和硝酸还原酶的途径诱导了NO爆发以及细胞死亡。[具体生物名称未给出]的自噬标志物CrATG8蛋白丰度在HL照射后增加，同时自噬相关基因（CrVPS34、CrATG1、CrATG3、CrATG4、CrATG6、CrATG7、CrATG8和CrATG12）的转录本丰度呈线性增加，而在存在NO清除剂2-(4-羧基苯基)-4,4,5,5-四甲基咪唑啉-1-氧基-3-氧化物（cPTIO）的情况下这些基因的表达受到抑制。在正常光照（50 μmol m⁻² s⁻¹）条件下，用NO供体亚硝基-L-乙酰青霉胺和亚硝基谷胱甘肽处理细胞，以阐明NO在自噬激活和细胞死亡中的作用。用0.05 mM或0.1 mM NO供体处理增加了ATG8蛋白和CrATG转录本的丰度，而在存在cPTIO的情况下这些丰度受到抑制。此外，用0.05 mM NO供体处理不影响细胞活力，而0.1 mM NO供体引起细胞生长的短暂下降和死亡，12小时后恢复。cPTIO的存在可阻止这种短暂效应。然而，用1 mM过氧化氢和0.1 mM NO供体处理增强了自噬诱导，并在24小时后导致细胞死亡。cPTIO处理可阻止过氧化氢和NO的相互作用。这意味着NO对于诱导细胞死亡和自噬的过氧化氢和NO的相互作用至关重要。此外，在非致死性高光（750 μmol m⁻² s⁻¹）条件下暴露于0.1 mM NO供体可诱发自噬和细胞死亡。总之，目前的研究结果表明，在致死性高强度光照下，[具体生物名称未给出]中NO介导的自噬途径被激活，并且可能与过氧化氢相互作用导致高光诱导的细胞死亡。文中还讨论了自噬与细胞死亡之间的关系。
