title: Silica Nanoparticles Induce Oxidative Stress and Autophagy but Not Apoptosis in the MRC-5 Cell Line.
abstract: This study evaluated the in vitro effects of 62.5 µg/mL silica nanoparticles (SiO NPs) on MRC-5 human lung fibroblast cells for 24, 48 and 72 h. The nanoparticles' morphology, composition, and structure were investigated using high resolution transmission electron microscopy, selected area electron diffraction and X-ray diffraction. Our study showed a decreased cell viability and the induction of cellular oxidative stress as evidenced by an increased level of reactive oxygen species (ROS), carbonyl groups, and advanced oxidation protein products after 24, 48, and 72 h, as well as a decreased concentration of glutathione (GSH) and protein sulfhydryl groups. The protein expression of Hsp27, Hsp60, and Hsp90 decreased at all time intervals, while the level of protein Hsp70 remained unchanged during the exposure. Similarly, the expression of p53, MDM2 and Bcl-2 was significantly decreased for all time intervals, while the expression of Bax, a marker for apoptosis, was insignificantly downregulated. These results correlated with the increase of pro-caspase 3 expression. The role of autophagy in cellular response to SiO₂NPs was demonstrated by a fluorescence-labeled method and by an increased level of LC3-II/LC3-I ratio. Taken together, our data suggested that SiO₂ NPs induced ROS-mediated autophagy in MRC-5 cells as a possible mechanism of cell survival.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest 050095, Romania. sori.petrache@yahoo.com.|Department of Experimental and Applied Biology, Institute of Life Sciences, Vasile Goldis Western University of Arad, 86 Rebreanu, Arad 310414, Romania. sori.petrache@yahoo.com.
authors.forename: Sorina Nicoleta
authors.initials: SN
authors.lastname: Petrache Voicu
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest 050095, Romania. diana_dinu2006@yahoo.com.
authors.forename: Diana
authors.initials: D
authors.lastname: Dinu
authors.affiliation: Laser Department, National Institute of Laser, Plasma and Radiation Physics, 409 Atomistilor, Bucharest-Magurele 077125, Romania. cornelia.sima@inflpr.ro.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Sima
authors.affiliation: Department of Experimental and Applied Biology, Institute of Life Sciences, Vasile Goldis Western University of Arad, 86 Rebreanu, Arad 310414, Romania. anca.hermenean@gmail.com.|Department of Histology, Faculty of Medicine, Pharmacy and Dentistry, Vasile Goldis Western University of Arad, 1 Feleacului, Arad 310396, Romania. anca.hermenean@gmail.com.
authors.forename: Anca
authors.initials: A
authors.lastname: Hermenean
authors.affiliation: Department of Experimental and Applied Biology, Institute of Life Sciences, Vasile Goldis Western University of Arad, 86 Rebreanu, Arad 310414, Romania. biologie@uvvg.ro.
authors.forename: Aurel
authors.initials: A
authors.lastname: Ardelean
authors.affiliation: Biochemistry Proteomics Department, Victor Babes National Institute of Pathology, 99-101 Splaiul Independentei, Bucharest 050096, Romania. raducan.elena@gmail.com.
authors.forename: Elena
authors.initials: E
authors.lastname: Codrici
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest 050095, Romania. miruna_stan@yahoo.com.
authors.forename: Miruna Silvia
authors.initials: MS
authors.lastname: Stan
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest 050095, Romania. otilia_zarnescu@yahoo.com.
authors.forename: Otilia
authors.initials: O
authors.lastname: Zărnescu
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest 050095, Romania. adin@bio.unibuc.ro.
authors.forename: Anca
authors.initials: A
authors.lastname: Dinischiotu
mesh_terms: D017209:Apoptosis; D001343:Autophagy; D002460:Cell Line; D002470:Cell Survival; D005978:Glutathione / Q000378:metabolism; D055551:HSP27 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D053758:Nanoparticles / Q000633:toxicity*; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D012822:Silicon Dioxide / Q000633:toxicity*
chemical_list: D055551:HSP27 Heat-Shock Proteins; D017382:Reactive Oxygen Species; D012822:Silicon Dioxide; D005978:Glutathione
keywords: MRC-5 cell line; SiO2 nanoparticles; apoptosis; autophagy; heat shock proteins; oxidative stress