Protective Effect of N-Acetylcysteine against Oxidative Stress Induced by Zearalenone via Mitochondrial Apoptosis Pathway in SIEC02 Cells

shRNA-interfered of Nrf2 reveals a critical role for Keap1-Nrf2 signaling pathway during effects of zearalenone induced oxidative stress in IPEC-J2 cells

OBJECTIVE

This study aims to verify the protective effect of the Kelch-like ECH-associated protein1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways by studying the effect of plasmids containing Nrf2-small hairpin RNA (shRNA) interference down-regulation of Nrf2 on zearalenone (ZEA)-induced intestinal porcine epithelial cells (IPEC-J2) oxidative stress.

METHODS

We constructed an IPEC-J2 model that interferes with Nrf2 expression, set blank (control), negative control group (Sh-control), positive control group (Sh-Nrf2), and added 10, 20, and 40 μmol/L ZEA experimental group (Sh-Nrf2+ZEA10, Sh-Nrf2+ZEA20, and Sh-Nrf2+ZEA40).

RESULTS

The study results showed that, compared with the Sh-Nrf2 group, ZEA significantly increased the apoptosis rate of IPEC-J2 in a time- and dose-dependent manner. Compared with the Sh-Nrf2 group, the activities of total superoxide dismutase and glutathione peroxidase and relative expressions of Keap1 at mRNA and protein level in the Sh-Nrf2+ZEA20 and Sh-Nrf2+ZEA40 groups were significantly reduced, the malondialdehyde level, and the fluorescence intensity around and within the nucleus of reactive oxygen species and Nrf2, and the relative expressions of Nrf2, quinone oxidoreductase 1, and hemeoxygenase 1 at mRNA and protein level significantly increased.

CONCLUSION

These results further prove that interfering with the expression of Nrf2 in IPEC-J2 cells affected the activation of the Keap1-Nrf2 signaling pathway and reduced the ability of cells to resist ZEA-induced oxidative stress. Therefore, the Keap1-Nrf2 signaling pathway had an important protective effect in ZEA-induced intestinal oxidative stress.

Tetra aniline-based polymers ameliorate BPA-induced cardiotoxicity in Sprague Dawley rats, in silico and in vivo analysis

AIMS

Bisphenol A (BPA), xenoestrogen, is an environmental toxicant, that generates oxidative stress leading to cardiotoxicity. The oxidative stress can be neutralized by natural and synthetic antioxidants. The present study elucidates the highly selective antioxidative potential of synthetic tetra aniline polymers Es-37 and L-37 against Bisphenol A-induced cardiac cellular impairments and the role of miRNA-15a-5p in the regulation of different apoptotic proteins.

MATERIALS AND METHODS

The molecular docking of L-37 and Es-37 with three proteins (p53, Cytochrome c, and Bcl-2) were performed. The dose of 1 mg/kg BW of BPA, 1 mg/kg BW Es-37 and L-37 and 50 mg/kg BW N-acetyl cysteine (NAC) was administered to Sprague Dawley rats. The miRNA and target gene expression were confirmed by qRt-PCR and Immunoblotting.

KEY FINDINGS

In our results, BPA administration significantly elevated the reactive oxygen species (ROS), p53, cytochrome c, and particularly miRNA-15a-5p expression; however: these changes were notably reversed by Es-37 and L-37 treatment. Additionally, molecular docking of synthetic polymers validated that L-37 has a greater binding affinity with the target proteins compared to Es-37, with the highest binding values reported for the enzymatic protein cytochrome c.

SIGNIFICANCE

These results suggest that both synthetic polymers Es-37 and L-37 have the potential to scavenge free radicals, boost-up antioxidant enzyme activities, and avert (BPA-induced) toxicity, thus, may serve as cardioprotective agents. Moreover, this study first time proposes that miRNA-15a-5p overexpression is associated with oxidative stress and coincides with BPA induced cardiotoxicity, thus may serve as potential therapeutic target in future.

Apoptosis mediated by crosstalk between mitochondria and endoplasmic reticulum: A possible cause of citrinin disruption of the intestinal barrier

Citrinin (CTN) is a mycotoxin commonly found in contaminated foods and feed, posing health risks to both humans and animals. However, the mechanism by which CTN damages the intestine remains unclear. In this study, a model of intestinal injury was induced by administering 1.25 mg/kg and 5 mg/kg of CTN via gavage for 28 consecutive days in 6-week-old Kunming mice, aiming to explore the potential mechanisms underlying intestinal injury. The results demonstrate that CTN can cause structural damage to the mouse jejunum. Additionally, CTN reduces the protein expression of Claudin-1, Occludin, ZO-1, and MUC2, thereby disrupting the physical and chemical barriers of the intestine. Furthermore, exposure to CTN alters the structure of the intestinal microbiota in mice, thus compromising the intestinal microbial barrier. Meanwhile, the results showed that CTN exposure could induce excessive apoptosis in intestinal cells by altering the expression of proteins such as CHOP and GRP78 in the endoplasmic reticulum and Bax and Cyt c in mitochondria. The mitochondria and endoplasmic reticulum are connected through the mitochondria-associated endoplasmic reticulum membrane (MAM), which regulates the membrane. We found that the expression of bridging proteins Fis1 and BAP31 on the membrane was increased after CTN treatment, which would exacerbate the endoplasmic reticulum dysfunction, and could activate proteins such as Caspase-8 and Bid, thus further inducing apoptosis via the mitochondrial pathway. Taken together, these results suggest that CTN exposure can cause intestinal damage by disrupting the intestinal barrier and inducing excessive apoptosis in intestinal cells.

Inhibiting the Keap1/Nrf2 Protein-Protein Interaction with Protein-Like Polymers

Successful and selective inhibition of the cytosolic protein-protein interaction (PPI) between nuclear factor erythroid 2-related factor 2 (Nrf2) and Kelch-like ECH-associating protein 1 (Keap1) can enhance the antioxidant response, with the potential for a therapeutic effect in a range of settings including in neurodegenerative disease (ND). Small molecule inhibitors have been developed, yet many have off-target effects, or are otherwise limited by poor cellular permeability. Peptide-based strategies have also been attempted to enhance specificity, yet face challenges due to susceptibility to degradation and lack of cellular penetration. Herein, these barriers are overcome utilizing a polymer-based proteomimetics. The protein-like polymer (PLP) consists of a synthetic, lipophilic polymer backbone displaying water soluble Keap1-binding peptides on each monomer unit forming a brush polymer architecture. The PLPs are capable of engaging Keap1 and displacing the cellular protective transcription factor Nrf2, which then translocates to the nucleus, activating the antioxidant response element (ARE). PLPs exhibit increased Keap1 binding affinity by several orders of magnitude compared to free peptides, maintain serum stability, are cell-penetrant, and selectively activate the ARE pathway in cells, including in primary cortical neuronal cultures. Keap1/Nrf2-inhibitory PLPs have the potential to impact the treatment of disease states associated with dysregulation of oxidative stress, such as NDs.

The protective effect of Thai rice bran on N-acetyl-ρ-aminophen-induced hepatotoxicity in mice

Background and purpose

N-acetyl-ρ-aminophen (APAP) is a widely used medication with analgesic and antipyretic characteristics. High paracetamol doses can damage the liver. Thai-pigmented rice may treat numerous liver disorders due to its antioxidant, anti-inflammatory, and glutathione-restoring capabilities. This study aimed to evaluate the phenolic components in three Thai rice bran extracts and their antioxidant and hepatoprotective activities in an animal model.

Experimental approach

Fifty male mice were randomly assigned to the control and APAP studies. Each study was divided into 5 groups (n = 5) treated with distilled water, Hom Mali, Hang-Ngok, and Hom Nil (HN) rice compared with N-acetylcysteine with/without 60 mg/kg/day of APAP orally once a day for two weeks. Blood and liver sampling were collected for analysis.

Findings/Results

HN rice bran exhibited higher contents of total phenolic, total flavonoid, total anthocyanin, ferric-reducing antioxidant, and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activities than Hom Mali and Hang-Ngok. Anthocyanin was merely detected in HN. Following APAP administration, mice exhibited significant increases in hepatic enzymes including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6)), and malondialdehyde (MDA), but lower levels of antioxidant enzymes and glutathione profiles. Amongst the three cultivars, HN rice was the only compound that decreased MDA, ALT, AST, TNF-α, and IL-6 while increasing antioxidant enzyme activity such as superoxide dismutase, catalase, and glutathione peroxidase that was very close to that of N-acetylcysteine groups.

Conclusion and implications

Given the hepatoprotective and antioxidant properties, HN has the potential to be used as a health supplement.

STING dependent BAX-IRF3 signaling results in apoptosis during late-stage Coxiella burnetii infection

STING (STimulator of Interferon Genes) is a cytosolic sensor for cyclic dinucleotides (CDNs) and initiates an innate immune response upon binding to CDNs. Coxiella burnetii is a Gram-negative obligate intracellular bacterium and the causative agent of the zoonotic disease Q fever. The ability of C. burnetii to inhibit host cell death is a critical factor in disease development. Previous studies have shown that C. burnetii inhibits host cell apoptosis at early stages of infection. However, during the late-stages of infection, there is host cell lysis resulting in the release of bacteria to infect bystander cells. Thus, we investigated the role of STING during late-stages of C. burnetii infection and examined STING's impact on host cell death. We show that the loss of STING results in higher bacterial loads and abrogates IFNβ and IL6 induction at 12 days post-infection. The absence of STING during C. burnetii infection significantly reduces apoptosis through decreased caspase-8 and -3 activation. During infection, STING activates IRF3 which interacts with BAX. BAX then translocates to the mitochondria, which is followed by mitochondrial membrane depolarization. This results in increased cytosolic mtDNA in a STING-dependent manner. The presence of increased cytosolic mtDNA results in greater cytosolic 2'-3' cGAMP, creating a positive feedback loop and leading to further increases in STING activation and its downstream signaling. Taken together, we show that STING signaling is critical for BAX-IRF3-mediated mitochondria-induced apoptosis during late-stage C. burnetii infection.

Insights into the intestinal toxicity of foodborne mycotoxins through gut microbiota: A comprehensive review

Mycotoxins, which are fungal metabolites, pose a significant global food safety concern by extensively contaminating food and feed, thereby seriously threatening public health and economic development. Many foodborne mycotoxins exhibit potent intestinal toxicity. However, the mechanisms underlying mycotoxin-induced intestinal toxicity are diverse and complex, and effective prevention or treatment methods for this condition have not yet been established in clinical and animal husbandry practices. In recent years, there has been increasing attention to the role of gut microbiota in the occurrence and development of intestinal diseases. Hence, this review aims to provide a comprehensive summary of the intestinal toxicity mechanisms of six common foodborne mycotoxins. It also explores novel toxicity mechanisms through the "key gut microbiota-key metabolites-key targets" axis, utilizing multiomics and precision toxicology studies with a specific focus on gut microbiota. Additionally, we examine the potential beneficial effects of probiotic supplementation on mycotoxin-induced toxicity based on initial gut microbiota-mediated mycotoxicity. This review offers a systematic description of how mycotoxins impact gut microbiota, metabolites, and genes or proteins, providing valuable insights for subsequent toxicity studies of mycotoxins. Furthermore, it lays a theoretical foundation for preventing and treating intestinal toxicity caused by mycotoxins and advancing food safety practices.

Effects of N-Acetylcysteine Supplementation on Oxidative Stress and Expression of Apoptosis-Related Genes in Testicular Tissue of Rats Exposed to Lead

BACKGROUND

Lead occupational exposure is now a main concern in the modern world. Lead is a non-biodegradable element with multi-devastating effects on different organs. Acute or chronic exposure to lead is reported to be one of the most important causes of infertility both in males and females basically by inducing oxidative stress and apoptosis.

OBJECTIVES

The current study scrutinized the mitigating effects of N-acetylcysteine (NAC) on lead toxicity, oxidative stress, and apoptotic/anti-apoptotic genes in the testis tissues of male rats.

METHODS

Rats were randomly divided into a control group (G1) and four study groups treated with single and continuous doses of lead with and without NAC administration. Malondialdehyde (MDA), total antioxidant capacity (TAC), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were analyzed as oxidative stress biomarkers and the expression of apoptosis-related genes was studied using RT-PCR.

RESULTS

Continuous exposure to lead caused a significant decrease in sperm count, motility, viability, and morphology (P < 0.001). Number of germinal cells, Leydig cells, spermatocytes, and the diameter of seminiferous tubule were significantly decreased (P < 0.001) in G3 group. Continuous exposure to lead significantly decreased TAC content, but increased the levels of MDA and 8-OHdG (P < 0.001). Administration of continuous dose of lead dramatically increased expression of Bax, Caspase-3, Caspase-8, Cytochrome-C, MMP2, and MMP9 genes in testicular tissue. NAC treatments not only improved morphological changes and sperm quality, but also enhanced antioxidant balance and modulated apoptosis process in testicular tissue of rats.

CONCLUSION

Lead exposure strongly motivated testicular cells towards apoptosis, caused an oxidant/antioxidant imbalance, and decreased sperm quality along with morphological changes in testis cells. NAC treatments was associated with protective effects on testicular tissue mainly by rebalancing of the antioxidants capacity, as well as downregulation of apoptosis-related genes.

Voltage dependent anion channel and its interaction with N-acetyl-L-Cysteine (NAC) under oxidative stress on planar lipid bilayer

Mitochondria are the major source of Hydrogen Peroxide (H₂O₂), a reactive oxygen species, in the cells. The reactive oxygen species generated by the mitochondria oxidize major proteins including Voltage Dependent Anion Channel (VDAC). We were interested to know how the effect of H₂O₂ is countered by antioxidants present around the mitochondria. N-Acetyl-l-Cysteine (NAC) is a naturally existing antioxidant in the cells. Keeping this in view, the modulatory effect of antioxidant NAC on H₂O₂ oxidized VDAC has been investigated through in vitro electrophysiological studies. First, the effect of H₂O₂ and NAC was studied on independently incorporated single-channel VDAC. It was observed that NAC suppresses VDAC conductance with a half-maximal inhibitory concentration (IC₅₀) of ∼1.04 μM. In contrast, H₂O₂ enhances VDAC conductance. Later, oxidative stress was induced by H₂O₂ on VDAC increased conductance with half-maximal effective concentration (EC₅₀) of ∼302 nM. An application of 1 μM NAC on H₂O₂ treated (300 nM) VDAC reversed the effect of oxidation. In the next step, NAC and H₂O₂ were added in reverse order. When oxidative stress was induced using H₂O₂, reduction in conductance by NAC was 4.5 ± 0.404 nS. The change in conductance is nearly 6.3%. However, if antioxidant NAC was incubated first followed by H₂O₂ treatment, the conductance of VDAC was 3.09 ± 0.27 nS. The change in conductance is near 33%. Both H₂O₂ and NAC also affected various conducting states of VDAC. In-silico studies indicated the binding of NAC at Lysine and Glutamic acid of VDAC. Hence, NAC was found to be effective in protection of VDAC against H₂O₂-induced oxidative stress due to its strong binding.

Anti-apoptotic properties of N-Acetyl cysteine and its effects on of Liver X receptor and Sirtuin 1 expression in the liver of rats exposed to Lead

BACKGROUND

This study aimed to evaluate the expression of Liver X receptor (Lxr), Sirtuin 1 (Sirt1), apoptotic-related genes, and the protective role of N-acetylcysteine (NAC) in the liver of rats treated with Lead (Pb).

METHODS

Rats were randomly divided into 5 groups, including G1 (control), G2 (single dose of Pb), G3 (continuous dose of Pb), G4 (single dose of Pb + NAC), and G5 (continuous dose of Pb + NAC). Lipid profiles and liver specific enzymes were assessed. Expression of Lxr, Sirt1, Bax and Caspase-3 genes was considered using RT-PCR.

RESULTS

Exposure to Pb caused a significant accumulation of Pb in the blood and liver tissue, increase in serum AST, ALT and ALP enzymes, as well as lipid profiles. Chronic exposure to Pb caused a significant decrease in Lxr (3.15-fold; p < 0.001) and Sirt1 (2.78-fold; p = 0.009), but significant increase in expression of Bax (4.49-fold; p < 0.001) and Caspase-3 (4.10-fold; p < 0.001) genes when compared to the control. Combined therapy with Pb + NAC in rats caused a significant decrease in AST, ALT and ALP values (28.93%, 20.80% and 28.86%, respectively) in the blood as compared to rats treated with Pb alone. Co-treated with Pb + NAC significantly increased the expression of Lxr (1.72-fold; p = 0.043) and Sirt1 (2.45-fold; p = 0.008), but decreased the expression of Bax (1.96-fold; p = 0.03) and Caspase 3 (2.22-fold; p = 0.029) genes when compared to rats treated with Pb alone.

CONCLUSION

Chronic exposure to Pb is strongly associated with accumulation of Pb in the blood and liver, hepatic cells apoptosis, down-expression of Lxr and Sirt1 genes and consequently liver injury and abnormal lipid profiles. NAC reversed the Pb-induced toxicity on the liver tissue.

Graphene Oxide Enhances Biogenesis and Release of Exosomes in Human Ovarian Cancer Cells

BACKGROUND

Exosomes, which are nanovesicles secreted by almost all the cells, mediate intercellular communication and are involved in various physiological and pathological processes. We aimed to investigate the effects of graphene oxide (GO) on the biogenesis and release of exosomes in human ovarian cancer (SKOV3) cells.

METHODS

Exosomes were isolated using ultracentrifugation and ExoQuick and characterized by various analytical techniques. The expression levels of exosome markers were analyzed via quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay.

RESULTS

Graphene oxide (10-50 μg/mL), cisplatin (2-10 μg/mL), and C6-ceramide (5-25 μM) inhibited the cell viability, proliferation, and cytotoxicity in a dose-dependent manner. We observed that graphene oxide (GO), cisplatin (CIS), and C6-Ceramide (C6-Cer) stimulated acetylcholine esterase and neutral sphingomyelinase activity, total exosome protein concentration, and exosome counts associated with increased level of apoptosis, oxidative stress and endoplasmic reticulum stress. In contrast, GW4869 treatment inhibits biogenesis and release of exosomes. We observed that the human ovarian cancer cells secreted exosomes with typical cup-shaped morphology and surface protein biomarkers. The expression levels of TSG101, CD9, CD63, and CD81 were significantly higher in GO-treated cells than in control cells. Further, cytokine and chemokine levels were significantly higher in exosomes isolated from GO-treated SKOV3 cells than in those isolated from control cells. SKOV3 cells pre-treated with N-acetylcysteine or GW4869 displayed a significant reduction in GO-induced exosome biogenesis and release. Furthermore, endocytic inhibitors decrease exosome biogenesis and release by impairing endocytic pathways.

CONCLUSION

This study identifies GO as a potential tool for targeting the exosome pathway and stimulating exosome biogenesis and release. We believe that the knowledge acquired in this study can be potentially extended to other exosome-dominated pathologies and model systems. Furthermore, these nanoparticles can provide a promising means to enhance exosome production in SKOV3 cells.

Isoliquiritigenin attenuates emodin-induced hepatotoxicity in vivo and in vitro through Nrf2 pathway

Emodin (EMO), the main bioactive component of Polygonum multiflorum, Rheum palmatum, Aloe vera and Cassia acutifolia, can cause severe hepatotoxicity. Isoliquiritigenin (ISL), a flavonoid compound from the Glycyrrhiza, has been reported to be the most potent antioxidant response element (ARE)-luciferase inducer among the main components of licorice. But the protective effect and underlying mechanism of ISL on liver injury induced by EMO has not been reported. This study aims to explore the role of nuclear transcription factor 2 (Nrf2) in EMO-induced hepatotoxicity and the protective effect of ISL. EMO treatment caused cytotoxicity in L-02 cells. Combined treatment of EMO with ISL effectively reversed changes in cell viability, reduced reactive oxygen species (ROS) generation and malondialdehyde (MDA) generation, enhanced the levels of glutathione (GSH) and super oxide dismutase (SOD) induced by EMO in L-02 cells. Furthermore, ISL could also phosphorylate mitogen-activated protein kinases (MAPKs) and up-regulate Kelth-like ECH-associated protein (Keap1). The pathways of MAPKs and Keap1 lead to the separation of Keap1 and Nrf2. Free Nrf2 transferred to the nucleus and enhanced the expression of phase II detoxification enzymes. In conclusion, our results are the first to highlight the beneficial role and relevant mechanisms of ISL in EMO-induced liver injury and provide novel insight into its application.

Resveratrol Protects against Zearalenone-Induced Mitochondrial Defects during Porcine Oocyte Maturation via PINK1/Parkin-Mediated Mitophagy

Mitochondria hold redox homeostasis and energy metabolism as a crucial factor during oocyte maturation, while the exposure of estrogenic mycotoxin zearalenone causes developmental incapacity in porcine oocyte. This study aimed to reveal a potential resistance of phytoalexin resveratrol against zearalenone during porcine oocyte maturation and whether its mechanism was related with PTEN-induced kinase 1 (PINK1)/Parkin-mediated mitophagy. Porcine oocytes were exposed to 20 μM zearalenone with or without 2 μM resveratrol during in vitro maturation. As for the results, zearalenone impaired ultrastructure of mitochondria, causing mitochondrial depolarization, oxidative stress, apoptosis and embryonic developmental incapacity, in which mitophagy was induced in response to mitochondrial dysfunction. Phytoalexin resveratrol enhanced mitophagy through PINK1/Parkin in zearalenone-exposed oocytes, manifesting as enhanced mitophagy flux, upregulated PINK1, Parkin, microtubule-associated protein light-chain 3 beta-II (LC3B-II) and downregulated substrates mitofusin 2 (MFN2), voltage-dependent anion channels 1 (VDAC1) and p62 expressions. Resveratrol redressed zearalenone-induced mitochondrial depolarization, oxidative stress and apoptosis, and accelerated mitochondrial DNA copy during maturation, which improved embryonic development. This study offered an antitoxin solution during porcine oocyte maturation and revealed the involvement of PINK1/Parkin-mediated mitophagy, in which resveratrol mitigated zearalenone-induced embryonic developmental incapacity.

The impact of Zearalenone on heat-stressed skeletal muscle in pigs

Heat stress (HS) and Zearalenone (ZEN) exposure affect growth, production efficiency, and animal welfare; and, under extreme situations, both can be lethal. Given that both HS and ZEN independently cause oxidative stress, we hypothesized that simultaneous exposure to HS and ZEN would cause greater oxidative stress in porcine skeletal muscle than either condition, alone. To address this hypothesis, crossbred, prepubertal gilts were treated with either vehicle control (cookie dough) or ZEN (40 μg/kg) and exposed to either thermoneutral (TN; 21.0 °C) or 12-h diurnal HS conditions (night: 32.2 °C; day: 35.0 °C) for 7 d. Pigs were euthanized immediately following the environmental challenge and the glycolytic (STW) and oxidative (STR) portions of the semitendinosus muscle were collected for analysis. In STR, malondialdehyde (MDA) concentration, a marker of oxidative stress, tended to increase following ZEN exposure (P = 0.08). HS increased CAT (P = 0.019) and SOD1 (P = 0.049) protein abundance, while ZEN decreased GPX1 protein abundance (P = 0.064) and activity (P = 0.036). In STR, HS did not alter protein expression of HSP27, HSP70, or HSP90. Conversely, in STW, MDA-modified proteins remained similar between all groups. Consistent with STR, ZEN decreased GPX1 (P = 0.046) protein abundance in STW. In STW, ZEN decreased protein abundance of HSP27 (P = 0.032) and pHSP27 (P = 0.0068), while HS increased protein expression of HSP70 (P = 0.04) and HSP90 (P = 0.041). These data suggest a muscle fiber type-specific response to HS or ZEN exposure, potentially rendering STR more susceptible to HS- and/or ZEN-induced oxidative stress, however, the combination of HS and ZEN did not augment oxidative stress.

Glyphosate-based herbicides induces autophagy in IPEC-J2 cells and the intervention of N-acetylcysteine

Glyphosate-based herbicides (GBHs) are the most widely used pesticide in the world, and its extensive use has increased pressures on environmental safety and potential human and livestock health risks. This study investigated the effects of GBHs on antioxidant capacity, inflammatory cytokines, and autophagy of porcine intestinal epithelial cells (IPEC-J2) and its molecular mechanism. Also, the protective effects of N-acetylcysteine (NAC) against the toxicity of GBHs were evaluated. Our results showed that the activities of antioxidant enzymes (SOD, GSH-Px) were decreased by GBHs. GBHs increased inflammatory factors (IL-1β, IL-6, TNF-α) and the mRNA expression of iNOS and COX-2. GBHs induced the up-regulation of Nrf2/HO-1 pathway and the phosphorylation of IκB-α and NFκB p65, up-regulation of LC3-II/LC3-I, and down-regulation of P62, and NFκB inhibitor decreased the mRNA expression of inflammatory cytokines (IL-1β, IL-6, IL-8). Moreover, NAC reduced the cytotoxicity by suppressing ROS levels, and changed the autophagy-related proteins such as the suppression of LC3-II conversion and up-regulation of P62. Our findings unveil a novel mechanism of GBHs effects on IPEC-J2 cells and NAC can reverse cytotoxicity to some extent.

Pyrroloquinoline quinone ameliorates liver injury in mice induced by cyclophosphamide

The current study aimed to investigate the potential ameliorative effects of pyrroloquinoline quinone (PQQ) on cyclophosphamide (CTX)-induced liver injury in mice. The liver injury model was established by injecting mice with CTX (80 mg/kg/day). Liver function indices, antioxidant enzyme activities, and inflammatory cytokines were evaluated. In addition, protein expression levels of the nuclear factor E2-related factor 2 (Nrf2) and nuclear factor kappa-B (NF-κB) pathways in the liver tissues were determined using western blot. The results indicated that PQQ decreased the serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and the malondialdehyde (MDA), interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α) levels in the liver tissues. Moreover, PQQ enhanced the activities of oxidative stress markers to alleviate CTX induced oxidative stress. Furthermore, the expression levels of heme oxygenase-1 (HO-1), glutamate-cysteine ligase modifier subunit (GCLM), and NAD(P)H quinone oxidoreductase 1 (NQO1) were significantly increased, and the expression levels of NF-κB p50, NF-κB p65, and inhibitor of NF-κB kinase alpha (IKKα) were significantly decreased after PQQ administration, suggesting that PQQ alleviated CTX-induced liver injury via activating the Nrf2-mediated antioxidant response pathway, and inhibiting the NF-κB-mediated inflammation pathway. Therefore, PQQ can be potentially used as a dietary supplement or functional foods for alleviating the CTX-induced liver injury.

Effects of N-Acetyl Cysteine on Genes Expression of c-myc, and Ask-1, Histopathological, Oxidative Stress, Inflammation, and Apoptosis in the Liver of Male Rats Exposed to Cadmium

This study aimed to consider the oxidative damage induced by cadmium (Cd) and apoptosis and the role of N-acetylcysteine (NAC) in preserving hepatic cells against Cd toxicity. Male rats were randomly divided into seven groups including G1 (control), G2 (single dose of Cd), G3 (continuous dose of Cd), G4 (single dose of Cd + continuous dose of NAC), and G5 (continuous dose of Cd + continuous dose of NAC). Hepatic cells apoptosis was measured using TUNEL assay method. Levels of malondialdehyde (MDA), TNF-α, IL-10, and total antioxidant capacity (TAC) were measured by specific kits. Expression of c-myc and Ask-1 genes was considered using RT-PCR. NAC treatments significantly improved TAC and IL-10, but decreased MDA and TNF-α values in rats that were exposed to a single and continuous dose of Cd (p < 0.05). Exposure to a single and continuous dose of Cd caused a significant increase in c-myc expression by 3.76-fold (p < 0.001) and 8.17-fold (p < 0.0001), respectively. Single and continuous dose treatment of Cd led to a significant increase in Ask1 expression by 4.38-fold (p < 0.001) and 13.52-fold (p < 0.001), respectively. NAC treatments significantly decreased the expression of c-myc, and Ask-1 in rats exposed to single or continuous Cd. Cd exposure is strongly associated with oxidative stress, inflammation, antioxidant depletion, and liver cells apoptosis. NAC can protect liver tissue against Cd by elevating antioxidants capacity, mitigating oxidative stress and inflammation, as well as down-regulating of apoptotic genes.

The Antagonistic Effect of Glutamine on Zearalenone-Induced Apoptosis via PI3K/Akt Signaling Pathway in IPEC-J2 Cells

Zearalenone (ZEN) is a non-steroidal estrogen mycotoxin produced by Fusarium fungi, which inevitably exists in human and animal food or feed. Previous studies indicated that apoptosis seems to be a key determinant of ZEN-induced toxicity. This experiment aimed to investigate the protective effects of Glutamine (Gln) on ZEN-induced cytotoxicity in IPEC-J2 cells. The experimental results showed that Gln was able to alleviate the decline of cell viability and reduce the production of reactive oxygen species and calcium (Ca²⁺) induced by ZEN. Meanwhile, the mRNA expression of antioxidant enzymes such as glutathione reductase, glutathione peroxidase, and catalase was up-regulated after Gln addition. Subsequently, Gln supplementation resulted in the nuclear fission and Bad-fluorescence distribution of apoptotic cells were weakened, and the mRNA expression and protein expression of pro-apoptotic genes and apoptotic rates were significantly reduced. Moreover, ZEN reduced the phosphorylation Akt, decreased the expression of Bcl-2, and increased the expression of Bax. Gln alleviated the above changes induced by ZEN and the antagonistic effects of Gln were disturbed by PI3K inhibitor (LY294002). To conclude, this study revealed that Gln exhibited significant protective effects on ZEN-induced apoptosis, and this effect may be attributed to the PI3K/Akt signaling pathway.

Selective oxidative stress induces dual damage to telomeres and mitochondria in human T cells

Oxidative stress caused by excess reactive oxygen species (ROS) accelerates telomere erosion and mitochondrial injury, leading to impaired cellular functions and cell death. Whether oxidative stress-mediated telomere erosion induces mitochondrial injury, or vice versa, in human T cells-the major effectors of host adaptive immunity against infection and malignancy-is poorly understood due to the pleiotropic effects of ROS. Here we employed a novel chemoptogenetic tool that selectively produces a single oxygen (1 O2 ) only at telomeres or mitochondria in Jurkat T cells. We found that targeted 1 O2 production at telomeres triggered not only telomeric DNA damage but also mitochondrial dysfunction, resulting in T cell apoptotic death. Conversely, targeted 1 O2 formation at mitochondria induced not only mitochondrial injury but also telomeric DNA damage, leading to cellular crisis and apoptosis. Targeted oxidative stress at either telomeres or mitochondria increased ROS production, whereas blocking ROS formation during oxidative stress reversed the telomeric injury, mitochondrial dysfunction, and cellular apoptosis. Notably, the X-ray repair cross-complementing protein 1 (XRCC1) in the base excision repair (BER) pathway and multiple mitochondrial proteins in other cellular pathways were dysregulated by the targeted oxidative stress. By confining singlet 1 O2 formation to a single organelle, this study suggests that oxidative stress induces dual injury in T cells via crosstalk between telomeres and mitochondria. Further identification of these oxidation pathways may offer a novel approach to preserve mitochondrial functions, protect telomere integrity, and maintain T cell survival, which can be exploited to combat various immune aging-associated diseases.

Downregulation of BORIS/CTCFL leads to ROS-dependent cellular senescence and drug sensitivity in MYCN-amplified neuroblastoma

Brother of Regulator of Imprinted Sites (BORIS) or CCCTC-binding factor like (CTCFL) is a nucleotide-binding protein, aberrantly expressed in various malignancies. Expression of BORIS has been found to be associated with the expression of oncogenes which regulate the reactive oxygen species (ROS) biogenesis, DNA double-strand break repair, regulation of stemness, and induction of cellular senescence. In the present study, we have analyzed the effects of knockdown of BORIS, a potential oncogene, on the induction of senescence and tumor suppression. Loss of BORIS downregulated the expression of critical oncogenes such as BMI1, Akt, MYCN, and STAT3, whereas overexpression increased their respective expression levels in MYCN-amplified neuroblastoma cells. BORIS knockdown exhibited high levels of ROS biogenesis, indicating an upregulated mitochondrial superoxide production and thereby induction of senescence. Our study also showed that the loss of BORIS facilitated cellular senescence through the disruption of telomere integrity via altering the expression of various proteins required for telomere capping (POT1, TRF2, and TIN1). In addition to affecting ROS production and DNA damage, BORIS knockdown sensitized the cells toward chemotherapeutic drugs and induced apoptosis. Tumor induction studies on in vivo xenograft mouse models showed that cells with loss of BORIS/CTCFL failed to induce tumors. From our study, we conclude that silencing BORIS/CTCFL influences tumor growth and proliferation by regulating key oncogenes. The results also indicated that the BORIS knockdown can cause cellular senescence and upon a combinatorial treatment with chemotherapeutic drugs can induce enhanced drug sensitivity in MYCN-amplified neuroblastoma cells.

N-Acetyl cysteine mitigates histopathological changes and inflammatory genes expressions in the liver of cadmium exposed rats

This study aimed to consider the expression of Nrf2, NLRP3 and caspase 1 genes, as well as oxidative stress, and the protective role of N-acetyl cysteine (NAC) in the liver of rats treated with cadmium (Cd). Male rats were randomly divided into five groups including G1 (control), G2 (single dose of Cd), G3 (continuous dose of Cd), G4 (single dose of Cd + NAC), and G5 (continuous dose of Cd + NAC). Levels of malondialdehyde (MDA) and total antioxidant capacity (TAC) were measured. Expression of Nrf2, NLRP3 and caspase 1 genes was considered using RT-PCR. NAC treatments significantly improved TAC, but decreased MDA values in rats that exposed to continuous dose of Cd (p<0.05). Exposure to continuous dose of Cd caused a significant decrease in Nrf2 expression by 2.46-fold (p<0.001), but enhanced expression of NLRP3 and Caspase 1 genes by 3.13-fold and 3.16-fold), respectively (p<0.001). Compared to rats that treated to continuous dose of Cd, NAC supplementation enhanced the expression of Nrf2 by 1.67-fold (p<0.001) and reduced the expression of NLRP3 and Caspase 1 genes by 1.39-fold (p<0.001) and 1.58-fold (p<0.001), respectively. Down-regulation of Nrf2 and overexpression of NLRP3 and caspase 1 seems to be one of the main mechanisms of Cd toxicity on liver tissue. NAC protects liver tissue against Cd-induced oxidative injuries via enhancement of Nrf2 expression and reduction of NLRP3 and caspase 1 genes.

Variation in resistance to oxidative stress in Oregon-(R)R-flare and Canton-S strains of Drosophila melanogaster

All aerobic organisms are susceptible to damage by reactive oxygen species (ROS). ROS-induced damage has been associated with aging and diseases such as metabolic syndrome and cancer. However, not all organisms develop these diseases, nor do they age at the same rate; this is partially due to resistance to oxidative stress, a quantitative trait attributable to the interaction of factors including genetics and environmental. Drosophila melanogaster represents an ideal system to study how genetic variation can affect resistance to oxidative stress. In this work, oxidative stress (total and mitochondrial ROS), antioxidant response, and Cap 'n' collar isoform C and Spineless gene expression, one pesticide resistant (Oregon R(R)-flare) and wild-type (Canton-S) strains of D. melanogaster, were analyzed to test resistance to basal oxidative stress. ROS, catalase, and superoxide dismutase were determined by flow cytometry, and Cap 'n' collar isoform C and Spineless expression by qRT-PCR. The intensity of oxidative stress due to the pro-oxidant zearalenone in both was evaluated by flow cytometry. Data confirm expected differences in oxidative stress between strains that differ in Cyp450s levels. The Oregon (R)R-flare showed greater ROS, total and mitochondrial, compared to Canton-S. Regarding oxidative stress genes expression Cap 'n' collar isoform C and Spineless (Ss), Oregon R(R)-flare strain showed higher expression. In terms of response to zearalenone mycotoxin, Canton-S showed higher ROS concentration. Our data show variation in the resistance to oxidative stress among these strains of D. melanogaster.

Mitochondrial stress response in drug-induced liver injury

Drug-induced liver injury (DILI) caused by the ingestion of medications, herbs, chemicals or dietary supplements, is a clinically widespread health problem. The underlying mechanism of DILI is the formation of reactive metabolites, which trigger mitochondrial oxidative stress and the opening of mitochondrial permeability transition (MPT) pores through direct toxicity or immune response, leading to cell inflammation, apoptosis, and necrosis. Traditionally, mitochondria play an indispensable role in maintaining the physiological and biochemical functions of cells by producing ATP and mediating intracellular signal transduction; drugs can typically stimulate the mitochondria and, in the case of sustained stress, can eventually cause impairment of mitochondrial function and metabolic activity. Meanwhile, the mitochondrial stress response, as an adaptive protective mechanism, occurs when mitochondrial homeostasis is threatened. In this review, we summarize the relevant frontier researches of the protective effects of mitochondrial stress response in DILI as well as the potential related mechanisms, thus providing some thoughts for the clinical treatment of DILI.

DL-Selenomethionine Alleviates Oxidative Stress Induced by Zearalenone via Nrf2/Keap1 Signaling Pathway in IPEC-J2 Cells

Zearalenone (ZEN) is a kind of nonsteroidal mycotoxin that is considered a risk affecting the safety of human food and livestock feed that causes oxidative damages in mammalian cells. Selenomethionine (SeMet) was indicated to have antioxidant activity and received great interest in investigating the role of SeMet as a therapeutic agent in oxidation. Therefore, the aim of this study was to investigate the hormetic role of DL-SeMet in porcine intestinal epithelial J2 (IPEC-J2) cells against ZEN-induced oxidative stress injury. As a result of this experiment, 30 μg/mL of ZEN was observed with significantly statistical effects in cell viability. Following the dose-dependent manner, 20 μg/mL was chosen for the subsequent experiments. Then, further results in the current study showed that the ZENinduced oxidative stress with subsequent suppression of the expression of antioxidant stress pathway-related genes species. Moreover, SeMet reversed the oxidative damage and cell death of ZEN toxins to some extent, by a Nrf2/Keap1-ARE pathway. The finding of this experiment provided a foundation for further research on the ZEN-caused cell oxidative damage and the cure technology.

Protective effect of glutamine and alanyl-glutamine against zearalenone-induced intestinal epithelial barrier dysfunction in IPEC-J2 cells

Zearalenone (ZEN), a nonsteroidal estrogenic mycotoxin, has a negative effect on porcine intestine. Glutamine (Gln) and alanyl-glutamine (Ala-Gln) are nutrients with potential preservation functions similar to those of the intestinal epithelial barrier. The protective role of Gln and Ala-Gln on ZEN-induced intestinal barrier dysfunction was evaluated in this study. Additionally, the ability of Gln and Ala-Gln to protect the intestinal barrier was investigated. Our results showed that lactate dehydrogenase (LDH) activity, paracellular permeability and reactive oxygen species (ROS) level were increased by ZEN, while the glutathione (GSH) level was decreased by ZEN. Gln and Ala-Gln promoted the proliferation of cells and attenuated the ZEN-induced increase in cytotoxicity, cell apoptosis and paracellular permeability. Gln and Ala-Gln alleviated barrier function damage, which was additionally induced by ZEN by increasing the antioxidant capacity of cells. In addition, Gln and Ala-Gln upregulated intestinal barrier associated gene expressions including pBD-1, pBD-2, MUC-2, ZO-1, occludin and claudin-3. This study revealed that Gln and Ala-Gln had similar effects in protecting intestinal epithelial barrier function against ZEN exposure in IPEC-J2 cells. A new treatment for alleviating ZEN-induced injury to the intestine through nutritional intervention is provided.

The effect of N-Acetyl cysteine on the expression of Fxr (Nr1h4), LXRα (Nr1h3) and Sirt1 genes, oxidative stress, and apoptosis in the liver of rats exposed to different doses of cadmium

The aim of this study was to consider the expression of farnesoid X receptor (Fxr), liver X receptor (LXRα) and sirtuin 1 (Sirt1), oxidative stress, inflammation, apoptosis, and the protective role of N-acetylcysteine (NAC) in the liver of rats treated with cadmium (Cd). 30 Wistar rats were divided into 5 groups: G1 (control), G2 (single dose of Cd), G3 (continuous dose of Cd), G4 (single dose of Cd + continuous dose of NAC), and G5 (continuous dose of Cd + continuous dose of NAC). The apoptosis of hepatic cells was measured using the TUNEL assay. Levels of malondialdehyde (MDA), IL-10, TNF-α, and total antioxidant capacity (TAC) were measured by specific kits. The expression of Fxr, LXRα, and Sirt1 genes and ratio of Bax/Bcl2 was considered using RT-PCR. While NAC treatment improved TAC and IL-10 values, it decreased MDA and TNF-α levels in the liver of rats exposed to Cd (P < 0.001). NAC decreased Bax/Bcl2 in the liver of G4 and G5 groups (P < 0.001). Exposure to a continuous dose of Cd decreased Fxr, LXRα, and Sirt1 expression by 36.65- (P < 0.001), 12.52- (P < 0.001) and 11.34-fold (P < 0.001) compared to control, respectively. NAC increased Fxr, LXRα, and Sirt1 expression (P < 0.01) and decreased Cd concentrations in both serum and tissue samples in G4 and G5 groups. Our results suggested that NAC protects liver tissue against Cd toxicity by elevating antioxidant capacity, mitigating oxidative stress, inflammation, apoptosis and up-regulation of FXR, LXR, and SIRT1 genes.

The effect of N-acetyl cysteine on oxidative stress and apoptosis in the liver tissue of rats exposed to cadmium

We considered the oxidative damage induced by cadmium (Cd) and apoptosis, and the role of N-acetylcysteine (NAC) in preserving cells against Cd toxicity in the liver of male rats. NAC significantly improved total antioxidant capacity (TAC) and decreased malondialdehyde (MDA) in rats exposed to single and continuous dose of Cd. Single and continuous exposure to Cd caused a significant increase in Bax expression (by 1.5-fold and 3.61-fold, respectively) and significant decrease in expression of Bcl2 compared to control (by 9.14-fold and 2.36-fold, respectively). The expression of Caspase 3 and 8 in rats exposed to Cd was significantly higher than control group (P < 0.05). NAC protects liver tissue against Cd by elevating antioxidants capacity, mitigating oxidative stress, as well as down-regulating of apoptotic factors.

Protective Role of Natural and Semi-Synthetic Tocopherols on TNFα-Induced ROS Production and ICAM-1 and Cl-2 Expression in HT29 Intestinal Epithelial Cells

Vitamin E, a fat-soluble compound, possesses both antioxidant and non-antioxidant properties. In this study we evaluated, in intestinal HT29 cells, the role of natural tocopherols, α-Toc and δ-Toc, and two semi-synthetic derivatives, namely bis-δ-Toc sulfide (δ-Toc)₂S and bis-δ-Toc disulfide (δ-Toc)₂S₂, on TNFα-induced oxidative stress, and intercellular adhesion molecule-1 (ICAM-1) and claudin-2 (Cl-2) expression. The role of tocopherols was compared to that of N-acetylcysteine (NAC), an antioxidant precursor of glutathione synthesis. The results show that all tocopherol containing derivatives used, prevented TNFα-induced oxidative stress and the increase of ICAM-1 and Cl-2 expression, and that (δ-Toc)₂S and (δ-Toc)₂S₂ are more effective than δ-Toc and α-Toc. The beneficial effects demonstrated were due to tocopherol antioxidant properties, but suppression of TNFα-induced Cl-2 expression seems not only to be related with antioxidant ability. Indeed, while ICAM-1 expression is strongly related to the intracellular redox state, Cl-2 expression is TNFα-up-regulated by both redox and non-redox dependent mechanisms. Since ICAM-1 and Cl-2 increase intestinal bowel diseases, and cause excessive recruitment of immune cells and alteration of the intestinal barrier, natural and, above all, semi-synthetic tocopherols may have a potential role as a therapeutic support against intestinal chronic inflammation, in which TNFα represents an important proinflammatory mediator.

Freeman P. Efficacy of Double-Dose Dapsone Combination Therapy in the Treatment of Chronic Lyme Disease/Post-Treatment Lyme Disease Syndrome (PTLDS) and Associated Co-infections: A Report of Three Cases and Retrospective Chart Review

Three patients with multi-year histories of relapsing and remitting Lyme disease and associated co-infections despite extended antibiotic therapy were each given double-dose dapsone combination therapy (DDD CT) for a total of 7-8 weeks. At the completion of therapy, all three patients' major Lyme symptoms remained in remission for a period of 25-30 months. A retrospective chart review of 37 additional patients undergoing DDD CT therapy (40 patients in total) was also performed, which demonstrated tick-borne symptom improvements in 98% of patients, with 45% remaining in remission for 1 year or longer. In conclusion, double-dose dapsone therapy could represent a novel and effective anti-infective strategy in chronic Lyme disease/ post-treatment Lyme disease syndrome (PTLDS), especially in those individuals who have failed regular dose dapsone combination therapy (DDS CT) or standard antibiotic protocols. A randomized, blinded, placebo-controlled trial is warranted to evaluate the efficacy of DDD CT in those individuals with chronic Lyme disease/PTLDS.

N-Acetyl Cysteine Modulates the Inflammatory and Oxidative Stress Responses of Rescued Growth-Arrested Dental Pulp Microtissues Exposed to TEGDMA in ECM

Dental pulp is exposed to resin monomers leaching from capping materials. Toxic doses of the monomer, triethyleneglycol dimethacrylate (TEGDMA), impact cell growth, enhance inflammatory and oxidative stress responses, and lead to tissue necrosis. A therapeutic agent is required to rescue growth-arrested tissues by continuing their development and modulating the exacerbated responses. The functionality of N-Acetyl Cysteine (NAC) as a treatment was assessed by employing a 3D dental pulp microtissue platform. Immortalized and primary microtissues developed and matured in the extracellular matrix (ECM). TEGDMA was introduced at various concentrations. NAC was administered simultaneously with TEGDMA, before or after monomer addition during the development and after the maturation stages of the microtissue. Spatial growth was validated by confocal microscopy and image processing. Levels of inflammatory (COX2, NLRP3, IL-8) and oxidative stress (GSH, Nrf2) markers were quantified by immunoassays. NAC treatments, in parallel with TEGDMA challenge or post-challenge, resumed the growth of the underdeveloped microtissues and protected mature microtissues from deterioration. Growth recovery correlated with the alleviation of both responses by decreasing significantly the intracellular and extracellular levels of the markers. Our 3D/ECM-based dental pulp platform is an efficient tool for drug rescue screening. NAC supports compromised microtissues development, and immunomodulates and maintains the oxidative balance.

Oxidative stress and apoptotic effects of copper and cadmium in the zebrafish liver cell line ZFL

•

Oxidative stress and apoptosis created by Cu²⁺ and Cd²⁺ insults were studied in ZFL.

•

Cu²⁺ and Cd²⁺ both created lipid peroxidation, causing oxidative stress in cytoplasm.

•

Mitochondrial superoxide was induced by Cd²⁺ but supressed by Cu²⁺.

•

Cu²⁺ suppressed Casp3 activity, resulting in suppressed the apoptosis.

•

Pre-treatments of low concentration of Cu²⁺ protected the cell from Cd²⁺ insults.

Copper (Cu) and cadmium (Cd) are widely used in industrial activities, resulting in Cu and Cd contamination in aquatic systems worldwide. Although Cu plays an essential role in many biological functions, an excessive amount of the metal causes cytotoxicity. In contrast, Cd is a non-essential metal that usually co-exists with Cu. Together, they cause oxidative stress in cells, leading to cell damage. These metal ions are also believed to cause cell apoptosis. In this study, we used a zebrafish liver cell line, ZFL, to study combined Cu and Cd cytotoxicity. Although Cd is more toxic than Cu, both were found to regulate the expression of oxidative stress related genes, and neither significantly altered the activity of oxidative stress related enzymes. Co-exposure tests with the antioxidant N-acetyl-l-cysteine and the Cu chelator bathocuproinedisulfonic acid disodium salt demonstrated that Cd toxicity was due to the oxidative stress caused by Cu, and that Cu at a low concentration could in fact exert an antioxidant effect against the oxidative stress in ZFL. Excessive Cu concentration triggered the expression of initiator caspases (caspase 8 and caspase 9) but suppressed that of an executioner caspase (caspase 3), halting apoptosis. Cd could only trigger the expression of initiator caspases; it could not halt apoptosis. However, a low concentration of Cu reduced the mitochondrial superoxide level, suppressing the Cd-induced apoptotic effects in ZFL.

Effects of zearalenone-induced oxidative stress and Keap1-Nrf2 signaling pathway-related gene expression in the ileum and mesenteric lymph nodes of post-weaning gilts

Zearalenone (ZEA) contamination of feed affects animal husbandry and the human health. Currently, the molecular mechanism underlying small intestine-related diseases caused by ZEA-induced oxidative stress is not well understood. In this study, we aimed to identify the mechanisms involved in ZEA (0.5-1.5 mg/kg)-induced oxidative stress in the ileum and mesenteric lymph nodes (MLNs) and the role of the Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in post-weaning gilts. Forty post-weaning gilts (Landrace × Yorkshire × Duroc) with an average body weight of 14.01 ± 0.86 kg were randomly allocated to four groups and fed a corn-soybean meal basal diet supplemented with < 0.1, 0.5, 1.0, or 1.5 mg/kg ZEA. The results showed that the activity of total superoxide dismutase and glutathione peroxidase decreased (p < 0.05) linearly and quadratically and that the content of malondialdehyde increased (p < 0.05) quadratically in the ileum and MLNs with increasing ZEA in the diet. Immunohistochemical analysis showed that the expression of Nrf2 and glutathione peroxidase 1 (Gpx1) immunoreactive proteins in the ileum and MLNs were significantly enhanced with increasing ZEA. The relative mRNA and protein expression of Nrf2, Gpx1, quinone oxidoreductase 1 (Nqo1), hemeoxygenase 1 (Ho1), modifier subunit of glutamate-cysteine ligase (Gclm), and catalytic subunit of glutamate-cysteine ligase (Gclc) increased (p < 0.05) linearly and quadratically, and the relative mRNA and protein expression of Keap1 decreased (p < 0.05) linearly and quadratically in the ileum with increasing ZEA concentrations in the diet. Further, the relative mRNA and protein expression of Nrf2 and Gpx1 increased (p < 0.05) linearly and quadratically, and the relative mRNA and protein expression of Nqo1, Ho1, and Gclm decreased (p < 0.05) quadratically in the MLNs as ZEA concentrations increased in the diet. Our results provide valuable genetic information on ZEA-induced oxidative stress in the ileum and MLNs of post-weaning gilts and have elucidated the key regulatory genes involved in the Keap1-Nrf2 signaling pathway. Results indicated that the Keap1-Nrf2 signaling pathway might be a key target to further prevent and treat ZEA-induced injury to the ileum in post-weaning gilts.

Activation of the p38/MAPK pathway regulates autophagy in response to the CYPOR-dependent oxidative stress induced by zearalenone in porcine intestinal epithelial cells

Zearalenone (ZEA) can widely contaminate crops and agricultural products. The ingestion of ZEA-contaminated food or feed affects the integrity and functions of the intestines. In this study, we aimed to find the potential protective mechanism against ZEA ingestion. We found that ZEA induced cell death in IPEC-J2 cells. Meanwhile, the cytoprotective autophagy was activated in ZEA-treated cells. Further studies demonstrated that a p38/MAPK inhibitor down-regulated autophagy and increased cell death compared to those of the controls. Furthermore, ZEA could induce the accumulation of ROS, and eliminating ROS with NAC resulted in a decline in cell death, p38/MAPK phosphorylation, and the expression of LC3-II compared to those of ZEA-group. In addition, cytochrome P450 reductase (CYPOR) was significantly increased in ZEA-treated cells compared to that in the controls, and an inhibitor of CYPOR decreased ROS levels and mitigated cell death compared to those of the ZEA-group. More importantly, we found that blocking both p38/MAPK signalling and autophagy could enhance CYPOR expression and elevate ROS levels. Overall, our study indicated that the p38/MAPK pathway could activate protective autophagy in response to the CYPOR-dependent oxidative stress that was induced by ZEA in IPEC-J2 cells.