The role of ATF3 in ZnO nanoparticle-induced genotoxicity and cytotoxicity in bronchial epithelial cells

A novel "cells-on-particles" cytotoxicity testing platform in vitro: design, characterization, and validation against engineered nanoparticle aerosol

The presented research introduces the "Cells-on-Particles" integrated aerosol sampling and cytotoxicity testing in vitro platform, which allows for the direct assessment of the biological effects of captured aerosol particles on a selected cell type without the need for extraction or resuspension steps. By utilizing particles with unaltered chemical and physical properties, the method enables simple and fast screening of biological effects on specific cell types, making it a promising tool for assessing the cytotoxicity of particulate matter in ambient and occupational air. Platforms fabricated from cellulose acetate (CA) and poly[ε]caprolactone (PCL) were proven to be biocompatible and promoted the attachment and growth of the human bronchial epithelial cell line BEAS-2B. The PCL platforms were exposed to simulated occupational aerosols of silver, copper, and graphene oxide nanoparticles. Each nanoparticle type exhibited different and dose-dependent cytotoxic effects on cells, evidenced by reduced cell viability and distinct, particle type-dependent gene expression patterns. Notably, copper nanoparticles were identified as the most cytotoxic, and graphene oxide the least. Comparing the "Cells-on-Particles" and submerged exposure ("Particles-on-Cells") testing strategies, BEAS-2B cells responded to selected nanoparticles in a comparable manner, suggesting the developed testing system could be proposed for further evaluation with more complex environmental aerosols. Despite limitations, including particle agglomeration and the need for more replicates to address variability, the "Cells-on-Particles" platform enables effective detection of toxicity induced by relatively low levels of nanoparticles, demonstrating good sensitivity and a relatively simpler procedure compared to standard 2D cell exposure methods.

Gene expression profiles and protein-protein interaction networks in THP-1 cells exposed to metal-based nanomaterials

We analyzed gene expression in THP-1 cells exposed to metal-based nanomaterials (NMs) [TiO2 (NM-100), ZnO (NM-110), SiO2 (NM-200), Ag (NM-300 K)]. A functional enrichment analysis of the significant differentially expressed genes (DEGs) identified the key modulated biological processes and pathways. DEGs were used to construct protein-protein interaction networks. NM-110 and NM-300 K induced changes in the expression of genes involved in oxidative and genotoxic stress, immune response, alterations of cell cycle, detoxification of metal ions and regulation of redox-sensitive pathways. Both NMs shared a number of highly connected protein nodes (hubs) including CXCL8, ATF3, HMOX1, and IL1B. NM-200 induced limited transcriptional changes, mostly related to the immune response; however, several hubs (CXCL8, ATF3) were identical with NM-110 and NM-300 K. No effects of NM-100 were observed. Overall, soluble nanomaterials NM-110 and NM-300 K exerted a wide variety of toxic effects, while insoluble NM-200 induced immunotoxicity; NM-100 caused no detectable changes on the gene expression level.

Identification of ZIP8-induced ferroptosis as a major type of cell death in monocytes under sepsis conditions

Sepsis is a heterogenous syndrome with concurrent hyperinflammation and immune suppression. A prominent feature of immunosuppression during sepsis is the dysfunction and loss of monocytes; however, the major type of cell death contributing to this depletion, as well as its underlying molecular mechanisms, are yet to be identified. In this study, we confirmed the monocyte loss in septic patients based on a pooled gene expression data of periphery leukocytes. Using the collected reference gene sets from databases and published studies, we identified ferroptosis with a greater capacity to distinguish between sepsis and control samples than other cell death types. Further investigation on the molecular drivers, by a genetic algorithm-based feature selection and a weighted gene co-expression network analysis, revealed that zrt-/irt-like protein 8 (ZIP8), encoded by SLC39A8, was closely associated with ferroptosis of monocytes during sepsis. We validated the increase of ZIP8 of monocytes with in vivo and in vitro experiments. The in vitro studies also showed that downregulation of ZIP8 alleviated the lipopolysaccharide-induced lipid peroxidation, as well as restoring the reduction of GPX4, FTH1 and xCT. These findings suggest that ferroptosis might be a key factor in the loss of monocytes during sepsis, and that the heightened expression of ZIP8 may facilitate this progression.

Roles of NRF2 in DNA damage repair

PURPOSE

The transcription factor NF-E2-related factor 2 (NRF2) is a master regulator widely involved in essential cellular functions such as DNA repair. By clarifying the upstream and downstream links of NRF2 to DNA damage repair, we hope that attention will be drawn to the utilization of NRF2 as a target for cancer therapy.

METHODS

Query and summarize relevant literature on the role of NRF2 in direct repair, BER, NER, MMR, HR, and NHEJ in pubmed. Make pictures of Roles of NRF2 in DNA Damage Repair and tables of antioxidant response elements (AREs) of DNA repair genes. Analyze the mutation frequency of NFE2L2 in different types of cancer using cBioPortal online tools. By using TCGA, GTEx and GO databases, analyze the correlation between NFE2L2 mutations and DNA repair systems as well as the degree of changes in DNA repair systems as malignant tumors progress.

RESULTS

NRF2 plays roles in maintaining the integrity of the genome by repairing DNA damage, regulating the cell cycle, and acting as an antioxidant. And, it possibly plays roles in double stranded break (DSB) pathway selection following ionizing radiation (IR) damage. Whether pathways such as RNA modification, ncRNA, and protein post-translational modification affect the regulation of NRF2 on DNA repair is still to be determined. The overall mutation frequency of the NFE2L2 gene in esophageal carcinoma, lung cancer, and penile cancer is the highest. Genes (50 of 58) that are negatively correlated with clinical staging are positively correlated with NFE2L2 mutations or NFE2L2 expression levels.

CONCLUSION

NRF2 participates in a variety of DNA repair pathways and plays important roles in maintaining genome stability. NRF2 is a potential target for cancer treatment.

ATF3 promotes ferroptosis in sorafenib-induced cardiotoxicity by suppressing Slc7a11 expression

Sorafenib is the unique recommended molecular-targeted drug for advanced hepatocellular carcinoma, but its clinical use is limited due to cardiotoxicity. As sorafenib is an efficient ferroptosis inducer, the pathogenesis of this compound to ferroptosis-mediated cardiotoxicity is worth further study. Mice were administered 30 mg/kg sorafenib intraperitoneally for 2 weeks to induce cardiac dysfunction and Ferrostatin-1 (Fer-1) was used to reduce ferroptosis of mice with sorafenib-induced cardiotoxicity. Sorafenib reduced levels of anti-ferroptotic markers involving Slc7a11 and glutathione peroxidase 4 (GPX4), increased malonaldehyde malondialdehyde, apart from causing obvious mitochondria damage, which was alleviated by Fer-1. In vitro experiments showed that Fer-1 inhibited lipid peroxidation and injury of H9c2 cardiomyoblasts induced by sorafenib. Both in vitro and in vivo experiments confirmed that the expression of Slc7a11 was down regulated in sorafenib-induced cardiotoxicity, which can be partially prevented by treatment with Fer-1. Overexpression of Slc7a11 protected cells from ferroptosis, while knock-down of Slc7a11 made cardiomyoblasts sensitive to ferroptosis caused by sorafenib. Finally, by comparing data from the GEO database, we found that the expression of ATF3 was significantly increased in sorafenib treated human cardiomyocytes. In addition, we demonstrated that ATF3 suppressed Slc7a11 expression and promoted ferroptosis. Based on these findings, we concluded that ATF3/Slc7a11 mediated ferroptosis is one of the key mechanisms leading to sorafenib-induced cardiotoxicity. Targeting ferroptosis may be a novel therapeutic approach for preventing sorafenib-induced cardiotoxicity in the future.

Effect of nano zinc oxide on proliferation and toxicity of human gingival cells

BACKGROUND

Periodontal dressing is used to cover the gum surface and protect the wound after periodontal surgery. Nanomaterials have been widely applied in dentistry in recent years. Zinc oxide (ZnO) is one of the main components of periodontal dressing.

AIM

This study aims to explore the toxicity ZnO nanoparticles (ZnO NPs) causes to human gingival fibroblast cells (HGF-1) and its effect on cell proliferation.

METHODS

First, we identified and analyzed HGF-1, including cell morphology, growth curve, and immunohistochemistry staining. Then, we treated HGF-1 with ZnO NP. Cell viability, the integrity of the cell membrane, oxidative damage, and apoptosis were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) release assay, fluorescent probe, and flow cytometry. Furthermore, the expression of murine double minute 2 (MDM2) and p53 was determined by quantitative real-time polymerase chain reaction (qPCR) and Western blotting. We finally overexpressed MDM2 in HGF-1 to verify the relationship between MDM2 and cell proliferation.

RESULTS

Our research indicated ZnO NPs did not affect cell proliferation at low concentrations. However, high-concentration ZnO NP inhibited cell proliferation, destroyed the integrity of cell membranes, and induced oxidative stress and apoptosis. In addition, high concentration of ZnO NPs inhibited the proliferation of HGF-1 by regulating the expression of MDM2 and p53.

CONCLUSION

High concentration of ZnO NP caused toxicity to HGF-1 cells and inhibited cell proliferation by regulating MDM2 and p53 expression.

Effect of nano zinc oxide on proliferation and toxicity of human gingival cells

BACKGROUND

Periodontal dressing is used to cover the gum surface and protect the wound after periodontal surgery. Nanomaterials have been widely applied in dentistry in recent years. Zinc oxide (ZnO) is one of the main components of periodontal dressing.

AIM

This study aims to explore the toxicity ZnO nanoparticles (ZnO NPs) causes to human gingival fibroblast cells (HGF-1) and its effect on cell proliferation.

METHODS

First, we identified and analyzed HGF-1, including cell morphology, growth curve, and immunohistochemistry staining. Then, we treated HGF-1 with ZnO NP. Cell viability, the integrity of the cell membrane, oxidative damage, and apoptosis were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) release assay, fluorescent probe, and flow cytometry. Furthermore, the expression of murine double minute 2 (MDM2) and p53 was determined by quantitative real-time polymerase chain reaction (qPCR) and Western blotting. We finally overexpressed MDM2 in HGF-1 to verify the relationship between MDM2 and cell proliferation.

RESULTS

Our research indicated ZnO NPs did not affect cell proliferation at low concentrations. However, high-concentration ZnO NP inhibited cell proliferation, destroyed the integrity of cell membranes, and induced oxidative stress and apoptosis. In addition, high concentration of ZnO NPs inhibited the proliferation of HGF-1 by regulating the expression of MDM2 and p53.

CONCLUSION

High concentration of ZnO NP caused toxicity to HGF-1 cells and inhibited cell proliferation by regulating MDM2 and p53 expression.

ATF3 contributes to brucine-triggered glioma cell ferroptosis via promotion of hydrogen peroxide and iron

Ferroptotic cell death is characterized by iron-dependent lipid peroxidation that is initiated by ferrous iron and H2O2 via Fenton reaction, in which the role of activating transcription factor 3 (ATF3) remains elusive. Brucine is a weak alkaline indole alkaloid extracted from the seeds of Strychnos nux-vomica, which has shown potent antitumor activity against various tumors, including glioma. In this study, we showed that brucine inhibited glioma cell growth in vitro and in vivo, which was paralleled by nuclear translocation of ATF3, lipid peroxidation, and increases of iron and H2O2. Furthermore, brucine-induced lipid peroxidation was inhibited or exacerbated when intracellular iron was chelated by deferoxamine (500 μM) or improved by ferric ammonium citrate (500 μM). Suppression of lipid peroxidation with lipophilic antioxidants ferrostatin-1 (50 μM) or liproxstatin-1 (30 μM) rescued brucine-induced glioma cell death. Moreover, knockdown of ATF3 prevented brucine-induced accumulation of iron and H2O2 and glioma cell death. We revealed that brucine induced ATF3 upregulation and translocation into nuclei via activation of ER stress. ATF3 promoted brucine-induced H2O2 accumulation via upregulating NOX4 and SOD1 to generate H2O2 on one hand, and downregulating catalase and xCT to prevent H2O2 degradation on the other hand. H2O2 then contributed to brucine-triggered iron increase and transferrin receptor upregulation, as well as lipid peroxidation. This was further verified by treating glioma cells with exogenous H2O2 alone. Moreover, H2O2 reversely exacerbated brucine-induced ER stress. Taken together, ATF3 contributes to brucine-induced glioma cell ferroptosis via increasing H2O2 and iron.

NRF2 deficiency sensitizes human keratinocytes to zinc oxide nanoparticles-induced autophagy and cytotoxicity

Zinc oxide nanoparticles (ZnO NPs) are one of the most commonly used metal oxide particles in many industrial fields. Many studies have shown that ZnO NPs induce harmful effects to human skin, but the mechanisms remain poorly understood. Our results showed that ZnO NPs concentration-dependently induced cytotoxicity, ROS accumulation, and mitochondrial dysfunction in HaCaT cells. The expressions of adaptive antioxidant response transcriptional factor NRF2 and autophagy-related proteins P62 and LC3 II/I were increased by ZnO NPs. Knock-down of NRF2 (NRF2-KD) sensitized the cells to ZnO NPs-induced autophagy and cytotoxicity while an autophagy inhibitor, 3-methyladenine, protected the cells from ZnO NPs-induced cell death. These results demonstrated that NRF2 deficiency sensitizes human keratinocytes to ZnO NPs induced autophagy and cytotoxicity, and proposed a key role of NRF2 in protecting skin cells against ZnO NPs through regulation of antioxidants and autophagy.

ATF3 Promotes Arsenic-Induced Apoptosis and Oppositely Regulates DR5 and Bcl-xL Expression in Human Bronchial Epithelial Cells

Arsenic is one of the most common environmental pollutants eliciting serious public health issues; however, it is also a well-recognized chemotherapeutic agent for acute promyelocytic leukemia. The association between arsenic exposure and lung diseases has been established, but underlying molecular mechanisms are poorly defined. Here we investigated the toxicology of arsenic in airway epithelium. Arsenic rapidly induced the activating transcription factor ATF3 expression through the JNK and p38 pathways. The ATF3-deficient BEAS-2B cells were relatively resistant to apoptosis upon arsenic exposure, indicating a facilitatory role of ATF3 in arsenic-induced apoptosis. We further showed that ATF3 oppositely regulated the transcription of death receptor (DR5) and Bcl2-like 1 (Bcl-xL) by directly binding to the promoter DR5 and Bcl-xL. Altogether, our findings establish ATF3 as a pro-apoptotic protein in arsenic-induced airway epithelial apoptosis through transcriptionally regulating DR5 and Bcl-xL, highlighting the potential of ATF3 as an early and sensitive biomarker for arsenic-caused lung injury.

ATF3 Suppresses Growth and Metastasis of Clear Cell Renal Cell Carcinoma by Deactivating EGFR/AKT/GSK3β/β-Catenin Signaling Pathway

Background

Clear cell renal cell carcinoma (ccRCC) is one of the most common malignant cancers in East Asia, with high incidence and mortality. Accumulating evidence has shown that ATF3 is associated with tumor progression.

Methods

Using qPCR, the expression of ATF3 was detected in 93 patients with ccRCC, including 24 paired normal and tumor tissues, which were used to further compare ATF3 expression through western blotting and immunohistochemistry. Lentivirus was used for the overexpression or knockdown of ATF3, and the consequent alteration in function was analyzed through CCK8 assay, colony formation assay, wound healing assay, invasion assay, and flow cytometry. The potential mechanism affected by ATF3 was analyzed through gene set enrichment analysis (GSEA) and verified using western blotting, invasion assay, or immunofluorescence staining. Furthermore, a xenograft mouse model was used to assess the function of ATF3 in vivo.

Results

ATF3 expression was significantly decreased in ccRCC compared to that in adjacent normal tissues. Through gain- and loss-of-function experiments performed in an in vitro assay, we found that ATF3 could regulate ccRCC cell proliferation, cycle progression, migration, and invasion. In the in vivo study, the xenograft mouse model revealed that ATF3 overexpression can inhibit the growth of ccRCC. Moreover, the mechanism analysis showed that suppression of ATF3 could lead to an increase the expression of β-catenin and promote β-catenin transfer to the nucleus, and might be affected by EGFR/AKT/GSK3β signaling.

Conclusion

ATF3 could be utilized as an independent protective factor to inhibit the progression of ccRCC. Potential treatment strategies for ccRCC include targeting the ATF3/EGFR/AKT/GSK3β/β-catenin signaling pathway.

Formation, characterization and application of arginine-modified chitosan/γ-poly glutamic acid nanoparticles as carrier for curcumin

A novel nanoparticle (NP) delivery carrier for curcumin based on electrostatic 6-deoxy-6-arginine modified chitosan (DAC) assembled by γ-poly-glutamic acid (γ-PGA) was prepared. The NP structure was evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Interactions between DAC and γ-PGA were characterized using Fourier transform infrared spectroscopy (FT-IR). The sustained release kinetics of curcumin-loaded NPs was investigated in simulated gastrointestinal fluids. After exposed to heating, pH, and NaCl aqueous solution, the stabilities of both normal and curcumin-loaded NPs were determined. The results showed that NPs achieved a high encapsulation efficiency (79.5%) and loading capacity (11.31%) for curcumin. The curcumin-loaded NPs displayed a sustained release profile under simulated gastrointestinal conditions. Under certain pH (3-9), salt (0-100 mM), and temperature (30 - 60 °C) conditions, the vehicles of curcumin showed better stability. This demonstrates that NPs can be used as stable carriers for curcumin.