The role of nuclear factor erythroid 2-related factor 2 (NRF2) in arsenic toxicity

Impacts of Inorganic Arsenic Exposure on Genetic Stability of Human Mesenchymal Stromal Cells

Human mesenchymal stem/stromal cells (hMSCs) can differentiate into mesoderm-type cells, making them suitable candidates for tissue repair therapies. However, their relatively low frequency in adult tissue necessitates ex vivo expansion prior to regenerative medicine applications, and therefore, long-term hMSC genetic stability during expansion should be studied. hMSC applications in regenerative medicine ensure commercial availability of normal karyotype human primary cells for toxicity assessment and hMSCs could serve as alternatives to immortalized human cell models. In this work, we evaluated the potential of hMSCs in toxicity testing using inorganic arsenic (iAs) as a case study. hMSCs were exposed to iAs at different durations to track cellular aging and study long-term genetic stability. iAs exposures (48 h) resulted in micronuclei induction. hMSCs were also exposed to iAs for 6 days to determine if hMSCs would become more susceptible to chromosomal damage following exposure to the model genotoxicant, mitomycin C (MMC). The culture duration and iAs exposure did not alter MMC potency, indicating that the hMSC susceptibility to chromosomal damage remained unchanged. We also used gene expression analysis to investigate the molecular impacts of iAs on hMSCs over the course of short (3 days total) and long (30 days total) experiments. Both iAs exposures activated biomarkers associated with oxidative stress, but not biomarkers for direct DNA damage, providing support for an indirect mode of action for iAs genotoxicity. Overall, this study establishes the utility of hMSCs as a new model for toxicity screening and provides mechanistic information underlying iAs toxicity.

Influence of freeze-thaw cycles on change of arsenic speciation and toxic effects to bacteria in paddy soil

Global warming increases the freeze-thaw (FT) cycles, however, the impact of increased FT cycles on the environmental behavior of arsenic (As) in soils and the toxic effect of As to microorganisms are still unknown. Herein, the influence of FT cycles on As forms, available As, and microbial community structure in paddy soils was investigated. After 60 FT cycles, the content of exchangeable As and residual state As decreased by 1.77% and 14.18%, respectively, while the carbonate-bound As, iron-manganese oxide-bound As, and organic-bound As increased by 4.53%, 6.5%, and 5.35%, respectively. The available As in soil and As(III) in soil water increased by 6.53 mg/kg and 38.9 μg/L, respectively. High throughput sequencing data indicated that FT cycles reduced Alpha diversity and significantly changed Beta diversity of soil microorganisms. FT cycles considerably enhanced the relative abundance of Sphingomonas and Lysobacter. Kyoto Encyclopedia of Genes and Genomes function predictions revealed that FT cycles significantly activated cellular gene segments involved in soil bacterial immunological disorders, cell motility, parasite infectious diseases, and neurological diseases. This study would serve as a reference for future study on environmental behavior and toxic effects of heavy metals in farm soils of seasonal FT aeras.

Effects of Ammonia Stress on the Antioxidant, Ferroptosis, and Immune Response in the Liver of Golden Pompano Trachinotus ovatus

Ammonia is the main harmful environmental substance affecting fish culture. The liver is the immune and metabolic organ of fish, and its physiological homeostasis will affect the health of the organism. In this study, healthy golden pompano Trachinotus ovatus juveniles were exposed to 5 mg/L (A5) and 10 mg/L (A10) ammonia-N stress for 7 days and then the variation characteristics of the physiological homeostasis of the liver were analyzed at multiple biological levels. After ammonia stress, the liver showed obvious morphological changes and stress responses. Specifically, the oxidative stress indexes, such as the activities of the anti-superoxide anion generation capacity (ASC) and superoxide dismutase (SOD), were elevated in the A5 and A10 groups, while the glutathione peroxidase (GPx) activity and glutathione (GSH) content were disturbed; the relative expression levels of the Nrf2 and NQO1 genes were increased in the A10 group, while the expressions of the Keap1 and HO1 were decreased in the A5 and A10 groups. Ferroptosis related genes, such as the relative expressions of NOX1, NCOA4, and FPN1 were increased in the A5 and A10 groups, PTGS2 and FTH1 were decreased in the A5 group but elevated in the A10 group, and p53, GPx4, SLC7A11, and NFS1 were only increased in the A10 group. Inflammation related genes, such as TNFα, IL1β, and IL8 relative expression levels, were increased in the A10 group, IL10 was increased in the A5 and A10 groups, while TGFβ was decreased in the A5 group but increased in the A10 group. Immune related genes, such as the expression levels of IgM and IgT, were increased in the A5 group but decreased in the A10 group. The integrated biomarker responses revealed that the hepatotoxicity of ammonia was concentration-dependent, and there was a high correlation between oxidative stress, ferroptosis, inflammation, and immune function changes. These results reveal the hepatotoxicity of ammonia stress on T. ovatus.

Anti-inflammatory and antioxidant effects of baicalein: targeting Nrf2, and NFĸB in neurodegenerative disease

Neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease, are characterized by progressive loss of neurons in the brain regions, including the hippocampus, cortex, substantia nigra, and striatum. Multiple pathological mechanisms drive this neuronal loss, including oxidative stress, chronic inflammation, mitochondrial dysfunction, protein misfolding, and excitotoxicity. Recent evidence suggests that these processes are intricately linked to the dysregulation of key signalling pathways, such as the IĸB/NFĸB, and KEAP1/Nrf2 pathways, which play central roles in neuroinflammation, oxidative stress, and mitochondrial functions, respectively. At present, no cure exists for neurodegenerative disorders, and available medications focus solely on symptomatic management. While these treatments provide temporary relief, their long-term use is often associated with adverse health effects. In this context, natural Phytoactive constituents like Baicalein, a bioactive flavonoid derived from Scutellaria baicalensis, have gained attention for their promising therapeutic potential. Baicalein has been shown to modulate the IĸB/NFĸB, and KEAP1/Nrf2 pathways, thereby mitigating neuroinflammation and oxidative stress while supporting mitochondrial health. It exerts anti-inflammatory effects by inhibiting NFĸB activation, thereby reducing the production of proinflammatory cytokines, such as TNF-α, IL-1β, IL-6, and NLRP3 inflammasome, and enzymes like COX-2, LOX, and iNOS, which are essential for innate and adaptive immune responses. Simultaneously, baicalein enhances the Nrf2 activation, promoting the expression of antioxidant enzymes like HO-1, NQO1, GPx, and SOD, thus countering oxidative stress. These findings highlight the potential of baiclalein as a complementary approach for managing neurodegenerative diseases, offering a safer and more holistic alternative to conventional therapies.

Arsenic Trioxide (ATOIII) Induces NAD(P)H Quinone Oxidoreductase 1 (NQO1) Expression in Hepatic and Extrahepatic Tissues of C57BL/6 Mice

Arsenic trioxide (ATOIII) has emerged as a potent therapeutic agent for acute promyelocytic leukemia (APL), yet its clinical application is often limited by significant adverse effects. This study investigates the molecular mechanisms underlying ATOIII's impact on cellular detoxification pathways, focusing on the regulation of NAD(P)H/quinone oxidoreductase (NQO1), a crucial enzyme in maintaining cellular homeostasis and cancer prevention. We explored ATOIII's effects on NQO1 expression in C57BL/6 mice and Hepa-1c1c7 cells, both independently and in combination with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a known NQO1 inducer. Our findings revealed that ATOIII significantly increased NQO1 expression in hepatic and extrahepatic tissues, as well as in Hepa-1c1c7 cells, at mRNA, protein, and activity levels. This upregulation occurred both in the presence and absence of TCDD. Mechanistically, we demonstrated that ATOIII promotes the nuclear translocation of both nuclear factor erythroid 2-related factor-2 (NRF2) and aryl hydrocarbon receptor (AHR) transcription factors. Furthermore, ATOIII exposure increased antioxidant response element (ARE)-driven reporter gene activity, indicating a transcriptional mechanism of NQO1 induction. Notably, gene silencing experiments confirmed the critical roles of both NRF2 and AHR in mediating ATOIII-induced NQO1 expression. In conclusion, ATOIII exposure is found to upregulate the NQO1 enzyme through a transcriptional mechanism via AHR- and NRF2- dependent mechanisms, offering valuable insights into its therapeutic mechanisms.

Enhancing degradation of antibiotic-combined pollutants by a hybrid system containing advanced oxidation and microbial treatment, a review

Antibiotics often co-exist with other pollutants, posing a significant threat to ecosystems. This review first examines the applications and limitations of microbial treatments for various types of antibiotic-combined pollutants. Then, it explores the mechanisms and application of hybrid systems that integrate advanced oxidation with microbial treatment, categorized into two-stage and intimately hybrid systems. Finally, the review highlights key knowledge gaps in hybrid systems and provides new insight into the removal of combined pollutants.

Calycosin alleviates ferroptosis and attenuates doxorubicin-induced myocardial injury via the Nrf2/SLC7A11/GPX4 signaling pathway

Background

Heart failure is primarily characterized by damage to the structure and function of the heart. Ferroptosis represents a form of programmed cell death, and studies indicate that it constitutes one of the primary mechanisms underlying cardiomyocyte death in heart failure. Calycosin, a natural compound derived from astragalus, exhibits various pharmacological properties, including anti-ferroptosis, antioxidant effects, and cardiovascular protection. Nonetheless, the specific role of Calycosin in the treatment of ferroptosis in heart failure remains poorly understood.

Objective

This study aims to elucidate the regulatory effect of Calycosin on ferroptosis and its influence on the treatment mechanisms of heart failure through in vivo and in vitro experiments.

Methods

A rat model of heart failure was induced using doxorubicin, and the cardiac function was evaluated through cardiac ultrasound examination and NT-Pro BNP detection. Myocardial injury was assessed using H&E staining and Masson staining. The extent of mitochondrial damage was evaluated through transmission electron microscopy. Concurrently, the level of ferroptosis was analyzed by measuring ferroptosis markers, including MDA, ferrous ions, the GSH/GSSG ratio, and GPX4 activity. Subsequently, the molecular mechanism by which Calycosin exerts its therapeutic effects in heart failure was investigated through immunofluorescence and Western blotting. Finally, H9c2 cardiomyocytes were treated with doxorubicin to simulate myocardial injury, and the mechanism by which Calycosin mediates its effects in the treatment of heart failure was further verified through Nrf2 gene silencing.

Results

Calycosin significantly improves cardiac function in rats, reduces serum NT-Pro BNP levels, and alleviates myocardial cell damage. Additionally, it significantly decreases the levels of ferroptosis in myocardial tissue, as confirmed through transmission electron microscopy and the assessment of ferroptosis markers, including MDA, ferrous ions, GSH, and GPX4 activity. At the molecular level, Calycosin exerts its effects by activating the Nrf2/SLC7A11/GPX4 signaling pathway, evidenced by the upregulation of Nrf2, SLC7A11, GPX4, GSS, and GCL protein expression. This process substantially enhances the antioxidant capacity of rat myocardial tissue and effectively suppresses ferroptosis in myocardial cells. The results obtained from both in vivo and in vitro experiments are consistent. Notably, when Nrf2 is silenced, the protective effect of Calycosin on the myocardium is markedly diminished.

Conclusion

Calycosin effectively treats doxorubicin-induced cardiac injury, and its therapeutic effect is likely closely associated with the activation of the Nrf2/SLC7A11/GPX4 signaling pathway and the inhibition of ferroptosis in myocardial cells. Consequently, Calycosin, as a promising compound against doxorubicin-induced cardiotoxicity, warrants further investigation.

ATF3 as a response factor to regulate Cd-induced reproductive damage by activating the NRF2/HO-1 ferroptosis pathway

Cadmium (Cd) has garnered significant attention due to reproductive toxicity in inducing ferroptosis. However, the specific mechanisms underlying Cd-induced germ cell ferroptosis remain poorly understood. This study aimed to systematically explore the molecular mechanisms of germ cell ferroptosis by investigating differential changes in transcription factors and proteins in male mice treated orally with CdCl2 (0.5 g/L) reaching postnatal day 60, alongside Leydig cell (TM3) and Sertoli cell (TM4) lines. Results demonstrated that Cd exposure led to increased iron overload and oxidative stress in mouse testes, disrupted intracellular mitochondrial morphology characteristic of ferroptosis. RNA sequencing revealed significant upregulation of Atf3 and Hmox1 in Cd-exposed germ cells, along with increased expression of ATF3 and HO-1. Intervention in ferroptosis or HO-1 effectively rescued cells from Cd-induced mortality by breaking the detrimental cycle between lipid peroxidation and HO-1 activation. Further findings showed that NRF2 and HO-1 expression was notably elevated upon ATF3 overexpression in TM3 and TM4 cells, activating the Keap1-Nrf2 pathway and triggering ferroptosis in testes, whereas NRF2 and HO-1 expression levels were reversed when ATF3 was silenced. This study provides novel insights into ATF3-mediated NRF2/HO-1 signaling in Cd-induced mitochondrial ferroptosis in testes, shedding light on the mechanisms underlying Cd-induced ferroptosis and testicular injury.

The emerging role of oxidative stress in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic immune-mediated condition that affects the digestive system and includes Crohn's disease (CD) and ulcerative colitis (UC). Although the exact etiology of IBD remains uncertain, dysfunctional immunoregulation of the gut is believed to be the main culprit. Amongst the immunoregulatory factors, reactive oxygen species (ROS) and reactive nitrogen species (RNS), components of the oxidative stress event, are produced at abnormally high levels in IBD. Their destructive effects may contribute to the disease's initiation and propagation, as they damage the gut lining and activate inflammatory signaling pathways, further exacerbating the inflammation. Oxidative stress markers, such as malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OHdG), and serum-free thiols (R-SH), can be measured in the blood and stool of patients with IBD. These markers are elevated in patients with IBD, and their levels correlate with the severity of the disease. Thus, oxidative stress markers can be used not only in IBD diagnosis but also in monitoring the response to treatment. It can also be targeted in IBD treatment through the use of antioxidants, including vitamin C, vitamin E, glutathione, and N-acetylcysteine. In this review, we summarize the role of oxidative stress in the pathophysiology of IBD, its diagnostic targets, and the potential application of antioxidant therapies to manage and treat IBD.