Identification of the function and regulatory network of circ_009773 in DNA damage induced by nanoparticles of neodymium oxide

Toxic Effects of Rare Earth Elements on Human Health: A Review

Rare earth elements (REEs) are a new type of material resource which have attracted significant attention in recent years. REEs have emerged as essential metals in modern-day technology due to their unique functions. The long-term, large-scale mining and utilization of rare earths has caused serious environmental pollution and constitutes a global health issue, which has raised concerns regarding the safety of human health. However, the toxicity profile of suspended particulate matter in REEs in the environment, which interacts with the human body, remains largely unknown. Studies have shown that REEs can enter the human body through a variety of pathways, leading to a variety of organ and system dysfunctions through changes in genetics, epigenetics, and signaling pathways. Through an extensive literature search and critical analysis, we provide a comprehensive overview of the available evidence, identify knowledge gaps, and make recommendations for future research directions.

Circ_0008657 regulates lung DNA damage induced by hexavalent chromium through the miR-203a-3p/ATM axis

Hexavalent chromium [Cr (VI)] is an important environmental pollutant and may cause lung injury when inhaled into the human body. Cr (VI) is genotoxic and can cause DNA damage, although the underlying epigenetic mechanisms remain unclear. To simulate the real-life workplace exposure to Cr (VI), we used a novel exposure dose calculation method. We evaluated the effect of Cr (VI) on DNA damage in human bronchial epithelial cells (16HBE and BEAS-2B) by calculating the equivalent real-time exposure dose of Cr (VI) (0 to 10 μM) in an environmental population. Comet experiments and olive tail moment measurements revealed increased DNA damage in cells exposed to Cr (VI). Cr (VI) treatment increased nuclear γ-H2AX foci and γ-H2AX protein expression, and caused DNA damage in the lung tissues of mice. An effective Cr (VI) dose (6 μM) was determined and used for cell treatment. Cr (VI) exposure upregulated circ_0008657, and knockdown of circ_0008657 decreased Cr (VI)-induced DNA damage, whereas circ_0008657 overexpression had the opposite effect. Mechanistically, we found that circ_0008657 binds to microRNA (miR)-203a-3p and subsequently regulates ATM serine/threonine kinase (ATM), a key protein involved in homologous recombination repair downstream of miR-203a-3p, thereby regulating DNA damage induced by Cr (VI). The present findings suggest that circ_0008657 competitively binds to miR-203a-3p to activate the ATM pathway and regulate the DNA damage response after environmental chemical exposure in vivo and in vitro.

Role of circular RNAs in DNA repair

Circular RNAs (circRNAs) exhibit a wide range of activities that allow them to participate in numerous cellular processes and make them relevant in a variety of diseases. In this regard, a key process in which circRNAs are involved, and which is the focus of this article, is DNA damage repair (DDR). This study aims to illustrate how circRNAs influence different DNA repair pathways, with particular emphasis on the underlying mechanisms. In addition, the potential medical applications of this knowledge are discussed, particularly in the diagnosis, prognosis and treatment of diseases. In this sense, circRNAs were found to play a crucial role in DNA repair processes by regulating the expression and activity of proteins involved in various DNA repair pathways. They influence the expression of DNA repair proteins by interacting with their mRNAs, sponging miRNAs that target these mRNAs, regulating transcription factors that bind to their promoters, modulating upstream signalling pathways, and affecting mRNA translation. Furthermore, circRNAs regulate the activity of DNA repair proteins by interacting directly with them, sequestering them in specific cellular compartments and controlling activation signalling or upstream DDR signalling.

The lncRNA H19/miR-29a-3p/SNIP1/c-myc regulatory axis is involved in pulmonary fibrosis induced by Nd2O3

Some rare earth elements are occupational and environmental toxicants and can cause organ and systemic damage; therefore, they have attracted global attention. Neodymium oxide (Nd2O3) is a rare earth element that is refined and significantly utilized in China. The long noncoding RNA (lncRNA) H19 is encoded by the H19/IGF2 imprinted gene cluster located on human chromosome 11p15.5. H19 has become a research focus due to its ectopic expression leading to the promotion of fibrosis. However, the mechanisms by which it causes pulmonary fibrosis are elusive. This investigation indicates that biologically active Nd2O3 increases H19, SNIP1, and c-myc, decreases miR-29a-3p, accelerates macrophage M2 polarization, and causes pulmonary fibrosis in mice lung tissues. In macrophage-differentiated THP-1 cells, Nd2O3 (25 μg/ml) enhanced H19, SNIP1, and c-myc, reduced miR-29a-3p, accelerated macrophages M2 polarization, and stimulated fibrogenic cytokine (TGF-β1) secretion. Furthermore, the coculturing of Nd2O3-treated macrophage-differentiated THP-1 cells. And human embryonic lung fibroblast cells activated lung fibroblast, which increases the levels of collagen I, α-SMA, p-Smad2/3, and Smad4, whereas H19 knockdown or miR-29a-3p upregulation in macrophages had opposite effects. Moreover, it was revealed that H19/miR-29a-3p/SNIP1/c-myc regulatory axis is involved in pulmonary fibrosis induced by Nd2O3. Therefore, this study provides new molecular insights into the mechanism of pulmonary fibrosis by Nd2O3.

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.

Circ_002363 is regulated by the RNA binding protein BCAS2 and inhibits neodymium oxide nanoparticle-induced DNA damage by non-homologous end-joining repair

Neodymium oxide nanoparticles (NPs-Nd₂O₃) are increasingly being used in industry and biomedicine, causing adverse health effects such as lung disease. However, the underlying molecular mechanisms controlling these adverse consequences are unknown at present. In this study, a human bronchial epithelial cell line (16HBE) was exposed to increasing concentrations of NPs-Nd₂O₃, and Sprague-Dawley rats were treated with NPs-Nd₂O₃ by intratracheal instillation. We found that NPs-Nd₂O₃ exposure induced DNA damage and down-regulated levels of circular RNA (circRNA) circ_002363 in 16HBE cells as well as in rat lung tissue. We also observed that circ_002363 levels in the serum of workers employed in the production of NPs-Nd₂O₃ diminished as the work time progressed, suggesting that circ_002363 may be a potential biomarker of lung injury. Functional experiments showed that circ_002363 significantly inhibited DNA damage induced by NPs-Nd₂O_3. RNA pull-down and western blot assays found that circ_002363 interacted with proteins PARP1/Ku70/Ku80/Rad50, which are critical participants in non-homologous end-joining (NHEJ) DNA repair. Moreover, we found that formation of circ_002363 was regulated by the RNA binding protein Breast Carcinoma Amplified Sequence 2 (BCAS2). The BCAS2 protein affected circ_002363 expression through interaction with Pre-DNA2, the host gene of circ_002363, in NPs-Nd₂O_3-exposed 16HBE cells. In conclusion, our findings show first that circ_002363, which is regulated by BCAS2, acts as regulator of DNA damage via the NHEJ pathway. These results enhance our understanding of the regulatory mechanisms controlling the actions of circular RNAs and highlight the relationship between genetics and epigenetics in the development of diseases following exposure to environmental chemicals.

Nanosafety: An Evolving Concept to Bring the Safest Possible Nanomaterials to Society and Environment

The use of nanomaterials has been increasing in recent times, and they are widely used in industries such as cosmetics, drugs, food, water treatment, and agriculture. The rapid development of new nanomaterials demands a set of approaches to evaluate the potential toxicity and risks related to them. In this regard, nanosafety has been using and adapting already existing methods (toxicological approach), but the unique characteristics of nanomaterials demand new approaches (nanotoxicology) to fully understand the potential toxicity, immunotoxicity, and (epi)genotoxicity. In addition, new technologies, such as organs-on-chips and sophisticated sensors, are under development and/or adaptation. All the information generated is used to develop new in silico approaches trying to predict the potential effects of newly developed materials. The overall evaluation of nanomaterials from their production to their final disposal chain is completed using the life cycle assessment (LCA), which is becoming an important element of nanosafety considering sustainability and environmental impact. In this review, we give an overview of all these elements of nanosafety.