Multiple RNA Profiling Reveal Epigenetic Toxicity Effects of Oxidative Stress by Graphene Oxide Silver Nanoparticles in-vitro.

Introduction: The increasing industrial and biomedical utilization of graphene oxide silver nanoparticles (GO-AgNPs) raises the concern of nanosafety: exposure to the AgNPs or GO-AgNPs increases the generation of reactive oxygen species (ROS), causes DNA damage and alters the expression of whole transcriptome including mRNA, miRNA, tRNA, lncRNA, circRNA and others. Although the roles of different RNAs in epigenetic toxicity are being studied during the last decade, but still we have little knowledge about the role of circle RNAs (circRNAs) in epigenetic toxicity. Methods: Rabbit fetal fibroblast cells (RFFCs) were treated with 0, 8, 16, 24, 32 and 48 μg/mL GO-AgNPs to test the cell viability and 24 μg/mL GO-AgNPs was selected as the experimental dose. After 24 h treatment with 24 μg/mL GO-AgNPs, the level of ROS, malondialdehyde (MDA), superoxide dismutase (SOD), intracellular ATP, glutathione peroxidase (GPx), and glutathione reductase (Gr) were measured in the RFFCs. High-throughput whole transcriptome sequencing was performed to compare the expression of circRNAs, long non-coding RNAs (lncRNA) and mRNA between 24 μg/mL GO-AgNPs-treated RFFCs and control cells. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was performed to validate the accuracy of circRNA sequencing data. Bioinformatics analyses were performed to reveal the potential functional roles and related pathways of differentially expressed circRNAs, lncRNA and mRNA and to construct a circRNA-miRNA-mRNA interaction network. Results: We found that 57 circRNAs, 75 lncRNAs, and 444 mRNAs were upregulated while 35 circRNAs, 21 lncRNAs, and 186 mRNAs were downregulated. These differentially expressed genes are mainly involved in the transcriptional mis-regulation of cancer through several pathways: MAPK signaling pathway (circRNAs), non-homologous end-joining (lncRNAs), as well as PPAR and TGF-beta signaling pathways (mRNAs). Conclusion: These data revealed the potential roles of circRNAs in the GO-AgNPs induced toxicity through oxidative damage, which would be the basis for further research to determine their roles in the regulation of different biological processes.