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Abstract: Given the growing interest in nanosized spinel-type ferrite nanoparticles for biomedical applications and the limited information on their safety, this study aimed to assess their cellular and genotoxic effects in an in vitro 3D human hepatic cell model (HepG2 spheroids). Ferrite nanoparticles – γFe2O3 (FeNPs; 14 ± 4 nm), Zn0.7Fe2.3O4 (ZnNPs; 14 ± 5 nm), and Mn0.4Fe2.6O4 (MnNPs; 7 ± 2 nm) – were synthesised through a microwave-assisted polyol route, functionalized with citric acid, and characterised using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). Nanoparticle uptake was analysed using TEM, cytotoxicity was measured with CellTiter-Glo®, and oxidative stress induction was assessed using the 2′,7′-Dichlorodihydrofluorescein diacetate (DCFH-DA) and malondialdehyde (MDA) assay. Genotoxic effects were evaluated using the comet, γH2AX and p-H3 assays. Cellular stress responses were assessed using toxicogenomic analysis. Significant cytotoxicity of the tested nanoparticles (0.1–250 µg/mL) was observed; however, TEM analysis revealed limited penetration to the outermost cell layers of spheroids. Notably, only FeNPs induced ROS generation, while MDA levels remained unchanged in all tested samples. Low DNA damage was detected at 24 h, but a significant increase was observed at 96 h (5–50 µg/mL). No increase in γH2AX or p-H3 was found. No substantial alterations in DNA damage or oxidative stress-response gene expression were detected. Altogether, our findings suggest that the effects of ferrite nanoparticles are time- and composition-dependent, underlining the importance of further mechanistic and chronic exposure evaluations in 3D cell models.
Keywords: DNA damage, genotoxicity, HepG2 spheroids, magnetic ferrite-based nanoparticles, ROS induction, safety assessment, toxicogenomics
Published in DiRROS: 27.01.2026; Views: 493; Downloads: 647
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Abstract: Background Ca2+ and H2O2 are second messengers that regulate a wide range of cellular events in response to different environmental and developmental cues. In plants, stress-induced H2O2 has been shown to initiate characteristic Ca2+ signatures; however, a clear picture of the molecular connection between H2O2-induced Ca2+ signals and H2O2-induced cellular responses is missing, particularly in cereal crops such as barley. Here, we employed RNA-seq analyses to identify transcriptome changes in roots and leaves of barley after H2O2 treatment under conditions that inhibited the formation of cytosolic Ca2+ transients. To that end, plasma membrane Ca2+ channels were blocked by LaCl3 application prior to stimulation of barley tissues with H2O2. Results We examined the expression patterns of 4246 genes that had previously been shown to be differentially expressed upon H2O2 application. Here, we further compared their expression between H2O2 and LaCl3 + H2O2 treatment. Genes showing expression patterns different to the previous study were considered to be Ca2+-dependent H2O2-responsive genes. These genes, numbering 331 in leaves and 1320 in roots, could be classified in five and four clusters, respectively. Expression patterns of several genes from each cluster were confirmed by RT-qPCR. We furthermore performed a network analysis to identify potential regulatory paths from known Ca2+-related genes to the newly identified Ca2+-dependent H2O2 responsive genes, using the recently described Stress Knowledge Map. This analysis indicated several transcription factors as key points of the responses mediated by the cross-talk between H2O2 and Ca2+. Conclusion Our study indicates that about 70% of the H2O2-responsive genes in barley roots require a transient increase in cytosolic Ca2+ concentrations for alteration in their transcript abundance, whereas in leaves, the Ca2+ dependency was much lower at about 33%. Targeted gene analysis and pathway modeling identified not only known components of the Ca2+ signaling cascade in plants but also genes that are not yet connected to stimuli-associated signaling. Potential key transcription factors identified in this study can be further analyzed in barley and other crops to ultimately disentangle the underlying mechanisms of H2O2-associated signal transduction mechanisms. This could aid breeding for improved stress resistance to optimize performance and productivity under increasing climate challenges.
Keywords: ROS, stress, RNA-Seq, Ca2+ signaling, crosstalk, Hordeum vulgare
Published in DiRROS: 03.04.2025; Views: 994; Downloads: 726
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Abstract: Many species of black yeasts can survive extremely harsh conditions and can quickly adapt to novel environments. These traits were proposed to have a role in the ability of some fungal species tocolonise indoor habitats inhospitable for majority of microorganisms, and to cause (opportunistic)infections in humans. In order to better understand the stress tolerance of black yeasts and thereby their opportunism, we focused our research on the three model black yeasts: the polyextremotolerant Au-reobasidium melanogenum and Exophiala dermatitidis, and the extremely halotolerant Hortaeawerneckii. These black yeasts are shown to thrive at temperatures, salinities, pH values and, H2O2 concentrations that inhibit growth of mesophilic species. Most importantly, unlike their close relatives they can not only grow, but also synthesize siderophores (E. dermatitidis) or degradeproteins (A. melanogenum) at 37 °C - traits that are crucial for pathogenesis in humans. These results support the hypothesis that the ability to cope with various environmental stresses is linked to the opportunistic behaviour of fungi. Therefore, better understanding of the connections between the stress-tolerant biology of black fungi and their ability to cause disease is needed, in particular due to their changing interactions with humans and their emerging pathogenicity.
Keywords: melanised fungi, temperature, NaCl, pH tolerance, ROS, oligotrophism, proteolytic activity, capsule
Published in DiRROS: 01.08.2024; Views: 1328; Downloads: 693
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