@article{
author = "Krunić, Matija and Ristić, Biljana and Bošnjak, Mihajlo and Paunović, Verica and Tovilović-Kovačević, Gordana and Zagović, Nevena and Mirčić, Aleksandar and Marković, Zoran and Todorović Marković, Biljana and Jovanović, Svetlana and Kleut, Duška and Mojović, Miloš and Nakarada, Đura and Marković, Olivera S. and Vuković, Irena and Harhaji-Trajković, Ljubica and Trajković, Vladimir",
year = "2021",
abstract = "We investigated the ability of graphene quantum dot (GQD) nanoparticles to protect SH-SY5Y human neuro blastoma cells from oxidative/nitrosative stress induced by iron-nitrosyl complex sodium nitroprusside (SNP).
GQD reduced SNP cytotoxicity by preventing mitochondrial depolarization, caspase-2 activation, and subsequent
apoptotic death. Although GQD diminished the levels of nitric oxide (NO) in SNP-exposed cells, NO scavengers
displayed only a slight protective effect, suggesting that NO quenching was not the main protective mechanism of
GQD. GQD also reduced SNP-triggered increase in the intracellular levels of hydroxyl radical (
•
OH), superoxide
anion (O2
•− ), and lipid peroxidation. Nonselective antioxidants, •
OH scavenging, and iron chelators, but not
superoxide dismutase, mimicked GQD cytoprotective activity, indicating that GQD protect cells by neutralizing •
OH generated in the presence of SNP-released iron. Cellular internalization of GQD was required for optimal
protection, since a removal of extracellular GQD by extensive washing only partly diminished their protective
effect. Moreover, GQD cooperated with SNP to induce autophagy, as confirmed by the inhibition of autophagy limiting Akt/PRAS40/mTOR signaling and increase in autophagy gene transcription, protein levels of proauto phagic beclin-1 and LC3-II, formation of autophagic vesicles, and degradation of autophagic target p62. The
antioxidant activity of GQD was not involved in autophagy induction, as antioxidants N-acetylcysteine and
dimethyl sulfoxide failed to stimulate autophagy in SNP-exposed cells. Pharmacological inhibitors of early
(wortmannin, 3-methyladenine) or late stages of autophagy (NH4Cl) efficiently reduced the protective effect of
GQD. Therefore, the ability of GQD to prevent the in vitro neurotoxicity of SNP depends on both •
OH/NO
scavenging and induction of cytoprotective autophagy.",
publisher = "Elsevier",
journal = "Free Radical Biology and Medicine",
title = "Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death",
volume = "177",
pages = "167-180",
doi = "10.1016/j.freeradbiomed.2021.10.025"
}
