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.     

Staphylococcal Enterotoxin H Induced Apoptosis of Bovine Mammary Epithelial Cells in Vitro

Staphylococcal enterotoxins (SEs) are powerful superantigenic toxins produced by Staphylococcus aureus (S. aureus). They can cause food poisoning and toxic shock. However, their impact on bovine mammary epithelial cells (bMECs) is still unknown. In this study, the distribution of SE genes was evaluated in 116 S. aureus isolates from bovine mastitis, and the most prevalent genes were seh (36.2%), followed by sei (12.1%), seg (11.2%), ser (4.3%), sec (3.4%), sea (2.6%) and sed (1.7%). To better understand the effect of staphylococcal enterotoxin H (SEH) on bMECs, the seh gene was cloned and inserted into the prokaryotic expression vector, pET28a, and transformed into Escherichia coli BL21 (DE3). The recombinant staphylococcal enterotoxin H (rSEH) was expressed and purified as soluble protein. Bioactivity analysis showed that rSEH possessed the activity of stimulating lymphocytes proliferation. The XTT assay showed that 100 μg/mL of rSEH produced the cytotoxic effect on bMECs, and fluorescence microscopy and flow cytometry analysis revealed that a certain dose of rSEH is effective at inducing bMECs apoptosis in vitro. This indicates that SEs can directly lead to cellular apoptosis of bMECs in bovine mastitis associated with S. aureus.     

Citrinin-Induced Hepatotoxicity in Mice Is Regulated by the Ca2+/Endoplasmic Reticulum Stress Signaling Pathway

Citrinin (CTN) is a mycotoxin found in crops and agricultural products and poses a serious threat to human and animal health. The aim of this study is to investigate the hepatotoxicity of CTN in mice and analyze its mechanisms from Ca²⁺-dependent endoplasmic reticulum (ER) stress perspective. We showed that CTN induced histopathological damage, caused ultrastructural changes in liver cells, and induced abnormal values of biochemical laboratory tests of some liver functions in mice. Treatment with CTN could induce nitric oxide (NO), malondialdehyde (MDA), and reactive oxygen species (ROS) accumulation in mice, accompanied with losses of activities of superoxide dismutase (SOD) and catalase (CAT), levels of glutathione (GSH), and capacities of total antioxidant (T-AOC), resulting in oxidative stress in mice. Furthermore, CTN treatment significantly increased Ca²⁺ accumulation, upregulated protein expressions of ER stress-mediated apoptosis signal protein (glucose regulated protein 78 (GRP78/BIP), C/EBP-homologous protein (CHOP), Caspase-12, and Caspase-3), and induced hepatocyte apoptosis. These adverse effects were counteracted by 4-phenylbutyric acid (4-PBA), an ER stress inhibitor. In summary, our results showed a possible underlying molecular mechanism for CTN that induced hepatocyte apoptosis in mice by the regulation of the Ca²⁺/ER stress signaling pathway.     

R(+)-Methanandamide Elicits a Cyclooxygenase-2-Dependent Mitochondrial Apoptosis Signaling Pathway in Human Neuroglioma Cells

Purpose Cannabinoids have been associated with tumor regression and apoptosis of cancer cells. Recently, we have shown that R(+)-methanandamide (R(+)-MA) induces apoptosis of H4 human neuroglioma cells via a mechanism involving de novo expression of the cyclooxygenase-2 (COX-2) enzyme. The present study investigated a possible involvement of a mitochondrial-driven pathway in this process. Methods Cell death was determined by the WST-1 cell viability test, and changes in apoptotic parameters [i.e., release of mitochondrial cytochrome c, activation of caspases, cleavage of poly(ADP-ribose) polymerase (PARP)] were detected by Western blotting. Results H4 cells treated with R(+)-MA showed typical signs of mitochondrial apoptosis, i.e., release of mitochondrial cytochrome c into the cytosol and activation of initiator caspase-9. Moreover, activation of the executor caspase-3 was observed following cannabinoid treatment. Cells were fully protected from apoptotic cell death by the caspase-3 inhibitor Ac-DEVD-CHO, indicating a crucial role for caspase-3 activation in R(+)-MA-elicited apoptosis. Furthermore, cleavage of the caspase-3 target protein PARP was registered. All of the aforementioned effects were substantially reduced by the selective COX-2 inhibitor celecoxib (1 μM) at a pharmacologically relevant, nonapoptotic concentration. Conclusion R(+)-MA-induced apoptosis is mediated via a mitochondrial-dependent pathway that becomes activated, at least in part, through up-regulation of the COX-2 enzyme.     

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.     

Phytochemicals Targeting Oxidative Stress,Interconnected Neuroinflammatory,and Neuroapoptotic Pathways Following Radiation

The radiation for therapeutic purposes has shown positive effects in different contexts; however, it can increase the risk of many age-related and neurodegenerative diseases such as Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), Huntington’s disease (HD), and Parkinson’s disease (PD). These different outcomes highlight a dose-response phenomenon called hormesis. Prevailing studies indicate that high doses of radiation could play several destructive roles in triggering oxidative stress, neuroapoptosis, and neuroinflammation in neurodegeneration. However, there is a lack of effective treatments in combating radiation-induced neurodegeneration, and the present drugs suffer from some drawbacks, including side effects and drug resistance. Among natural entities, polyphenols are suggested as multi-target agents affecting the dysregulated pathogenic mechanisms in neurodegenerative disease. This review discusses the destructive effects of radiation on the induction of neurodegenerative diseases by dysregulating oxidative stress, apoptosis, and inflammation. We also describe the promising effects of polyphenols and other candidate phytochemicals in preventing and treating radiation-induced neurodegenerative disorders, aiming to find novel/potential therapeutic compounds against such disorders.     

Estrogen Receptor β Participates in Alternariol-Induced Oxidative Stress in Normal Prostate Epithelial Cells

Alternaria toxins are considered as emerging mycotoxins, however their toxicity has not been fully evaluated in humans. Alternariol (AOH), the most prevalent Alternaria mycotoxin, was previously reported to be genotoxic and to affect hormonal balance in cells; however, its direct molecular mechanism is not known. The imbalance in androgen/estrogen ratio as well as chronic inflammation are postulated as factors in prostate diseases. The environmental agents affecting the hormonal balance might participate in prostate carcinogenesis. Thus, this study evaluated the effect of two doses of AOH on prostate epithelial cells. We observed that AOH in a dose of 10 µM induces oxidative stress, DNA damage and cell cycle arrest and that this effect is partially mediated by estrogen receptor β (ERβ) whereas the lower tested dose of AOH (0.1 µM) induces only oxidative stress in cells. The modulation of nuclear erythroid-related factor 2 (Nrf2) was observed in response to the higher dose of AOH. The use of selective estrogen receptor β (ERβ) inhibitor PHTPP revealed that AOH-induced oxidative stress in both tested doses is partially dependent on activation of ERβ, but lack of its activation did not protect cells against AOH-induced ROS production or DNA-damaging effect in case of higher dose of AOH (10 µM). Taken together, this is the first study reporting that AOH might affect basic processes in normal prostate epithelial cells associated with benign and malignant changes in prostate tissue.     

Zearalenone Induces Apoptosis in Porcine Endometrial Stromal Cells through JNK Signaling Pathway Based on Endoplasmic Reticulum Stress

Zearalenone (ZEA) is an estrogen-like mycotoxin characterized mainly by reproductive toxicity, to which pigs are particularly sensitive. The aim of this study was to investigate the molecular mechanism of ZEA-induced apoptosis in porcine endometrial stromal cells (ESCs) by activating the JNK signaling pathway through endoplasmic reticulum stress (ERS). In this study, ESCs were exposed to ZEA, with the ERS inhibitor sodium 4-Phenylbutyrate (4-PBA) as a reference. The results showed that ZEA could damage cell structures, induce endoplasmic reticulum swelling and fragmentation, and decreased the ratio of live cells to dead cells significantly. In addition, ZEA could increase reactive oxygen species and Ca²⁺ levels; upregulate the expression of GRP78, CHOP, PERK, ASK1 and JNK; activate JNK phosphorylation and its high expression in the nucleus; upregulate the expression Caspase 3 and Caspase 9; and increase the Bax/Bcl-2 ratio, resulting in increased apoptosis. After 3 h of 4-PBA-pretreatment, ZEA was added for mixed culture, which showed that the inhibition of ERS could reduce the cytotoxicity of ZEA toward ESCs. Compared with the ZEA group, ERS inhibition increased cell viability; downregulated the expression of GRP78, CHOP, PERK, ASK1 and JNK; and decreased the nuclear level of p-JNK. The Bax/Bcl-2 ratio and the expression of Caspase 3 and Caspase 9 were downregulated, significantly alleviating apoptosis. These results demonstrate that ZEA can alter the morphology of ESCs, destroy their ultrastructure, and activate the JNK signaling via the ERS pathway, leading to apoptosis.     

五味子乙素调控小神经胶质BV-2细胞氧化应激损伤的机制研究

目的 研究五味子乙素对H₂O₂诱导小神经胶质BV-2细胞氧化应激损伤的保护作用,并探讨其可能的作用机制。方法 体外常规培养BV-2细胞,用H₂O₂诱导细胞氧化应激损伤模型,将细胞分为正常对照组、模型组、五味子乙素10,20,40 μmol·L^-1组。CCK8试剂盒检测五味子乙素对细胞存活率的影响,相关试剂盒检测细胞匀浆中MDA、NO含量及SOD活性,免疫印迹方法检测Jak2、p-Jak2、State3、p-State3、HO-1及SOD1蛋白表达水平。结果 与模型组相比,不同剂量的五味子乙素可明显增加细胞的存活率、降低氧化应激产物MDA及NO的释放、增强SOD酶活性,差异均有统计学意义（P<0.05）;免疫印迹结果显示五味子乙素可明显提高HO-1、SOD1蛋白水平,并抑制Jak2、State3的磷酸化水平,与模型组相比差异有统计学意义（P<0.05）。结论 五味子乙素可明显降低BV-2细胞的氧化应激损伤,其作用机制可能与抑制Jak2/State3信号通路的活化有关。     

萝卜硫素对肾小管上皮细胞氧化应激及Nrf2/HO 1信号通路的影响

摘 要 目的：探讨萝卜硫素（SFN）对肾小管上皮细胞（HK-2）的氧化应激及核转录因子E2相关因子2（Nrf2）/血红素加氧酶（HO）-1信号通路的影响。方法: 体外培养HK-2细胞,将细胞分为空白对照组、H2O2处理组、H2O2+10 μmol·K^-1 SFN组、H2O2+20 μmol·K^-1 SFN组和H2O2+40 μmol·K^-1 SFN组;测定HK-2细胞中丙二醛（MDA）、一氧化氮（NO）、谷胱甘肽（GSH）的含量及超氧化物歧化酶（SOD）的活性;RT-PCR和Western Blot法分别检测Nrf2和HO-1 mRNA及蛋白表达水平。结果: 与空白对照组相比,H2O2处理组中MDA、NO含量明显升高,GSH水平和SOD酶活性显著降低（P<0.05）;经高、中、低3种浓度的萝卜硫素处理后MDA、NO含量显著降低,GSH水平显著升高,SOD酶活性也显著升高,Nrf2和HO 1mRNA及蛋白表达明显上调（P<0.05）。结论:萝卜硫素有抗HK 2细胞氧化应激损伤的作用,其作用机制可能与激活Nrf2/HO-1信号通路有关。     

The Role of Oxidative Stress, Metabolic Compromise, and Inflammation in Neuronal Injury Produced by Amphetamine-Related Drugs of Abuse

Methamphetamine (METH) and 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) are amphetamine derivatives with high abuse liability. These amphetamine-related drugs of abuse mediate their effects through the acute activation of both dopaminergic and serotonergic neurons. Long-term abuse of these amphetamine derivatives, however, results in damage to both dopaminergic and serotonergic terminals throughout the brain. This toxicity is mediated in part by oxidative stress, metabolic compromise, and inflammation. The overall objective of this review is to highlight experimental evidence that METH and MDMA increase oxidative stress, produce mitochondrial dysfunction, and increase inflammation that converge and culminate in the long-term toxicity to dopaminergic and serotonergic neurons.     

Anti-Apoptotic Effect of Flavokawain A on Ochratoxin-A-Induced Endothelial Cell Injury by Attenuation of Oxidative Stress via PI3K/AKT-Mediated Nrf2 Signaling Cascade

This study investigates the endothelial protective activity of flavokawain A (FKA) against oxidative stress induced by ochratoxin A (OTA), which acts as a mycotoxin, and its primary mechanisms in in vitro models. Reactive oxygen species, in general, regulate oxidative stress that significantly contributes to the pathophysiology of endothelial dysfunctions. OTA exerts toxicity through inflammation and the accumulation of ROS. This research is aimed at exploring the defensive function of FKA against the endothelial injury triggered by OTA through the Nrf2 pathway regulated by PI3K/AKT. OTA exposure significantly increased the nuclear translocation of NFκB, whereas we found a reduction in inflammation via NFκB inhibition with FKA treatment. FKA increased the PI3K and AKT phosphorylation, which may lead to the stimulation of antioxidative and antiapoptotic signaling in HUVECs. It also upregulated the phosphorylation of Nrf2 and a concomitant expression of antioxidant genes, such as HO-1, NQO-1, and γGCLC, depending on the dose under the oxidative stress triggered by OTA. Knockdown of Nrf2 through small interfering RNA (siRNA) impedes the protective role of FKA against the endothelial toxicity induced by OTA. In addition, FKA enhanced Bcl2 activation while suppressing apoptosis marker proteins. Therefore, FKA is regarded as a potential agent against endothelial oxidative stress caused by the deterioration of the endothelium. The research findings showed that FKA plays a key role in activating the p-PI3K/p-AKT and Nrf2 signaling pathways, while suppressing caspase-dependent apoptosis.     

瞿麦汤调控Nrf2/ARE信号通路对肾草酸钙结石大鼠氧化应激损伤作用机制研究

目的 研究敦煌医方瞿麦汤对肾草酸钙结石模型鼠核因子E2相关因子2（nuclear factor erythroid-2 related factor 2,Nrf2）/抗氧化反应原件（antioxidant response element,ARE）信号通路的影响,探讨其机制。方法 60只SD大鼠随机分为空白对照组、模型组、肾石通颗粒（5 g·kg^-1）组和敦煌医方瞿麦汤高、中、低剂量（20,10,5 g·kg^-1）组。除空白对照组外,其余各组大鼠采用1%乙二醇+2%氯化铵的溶液联合灌胃法制备大鼠肾草酸钙结石模型,同时给予相应药物,连续28 d。末次给药结束后,检测各组大鼠的体质量、肾指数,检测大鼠血清中SOD活性、MDA含量、T-AOC含量,HE染色法观察各组大鼠肾组织的病理形态学变化,RT-PCR法检测肾组织Nrf2 mRNA和NQO1 mRNA的表达,免疫组化法检测肾组织Nrf2和ARE的蛋白表达。结果 与空白对照组比较,模型组大鼠肾指数和MDA的含量均增加（P<0.05）,其体质量、SOD活性、T-AOC含量、Nrf2的基因表达和蛋白表达均下降,NQO1的基因表达下降（P<0.05）,ARE的蛋白表达下降（P<0.05）;与模型组比较,敦煌医方瞿麦汤各剂量组肾指数下降（P<0.05）,其体质量升高（P<0.05）;敦煌医方瞿麦汤中、高剂量组MDA含量下降（P<0.05）,Nrf2 mRNA和NQO1 mRNA的表达均升高（P<0.05）,Nrf2和ARE的蛋白表达均升高（P<0.05）;高剂量组T-AOC含量升高（P<0.05）。结论 肾草酸钙结石模型鼠存在氧化应激损伤,敦煌医方瞿麦汤可通过上调Nrf2/ARE信号通路相关因子表达抑制肾结石的形成来发挥治疗作用。     

Influence of A Continuous Very Low Dose of Gamma-Rays on Cell Proliferation,Apoptosis and Oxidative Stress

We have previously shown a delay of death by lymphoma in SJL/J mice irradiated with continuous very low doses of ionizing radiation. In order to understand the mechanisms involved in this phenomenon, we have irradiated in vitro the Raw264.7 monocytic and the YAC-1 lymphoma cell lines at very low-dose rate of 4cGy.month^-1. We have observed a transient increase in production of both free radicals and nitric oxide with a transient adaptive response during at least two weeks after the beginning of the irradiation. The slight decrease of Ki67 proliferation index observed during the second and third weeks of YAC-1 cells culture under irradiation was not significant but consistent with the shift of the proliferation assay curves of YAC-1cells at these same durations of culture. These in vitro results were in good agreement with the slightly decrease under irradiation of Ki67 proliferative index evaluated on lymphomatous lymph nodes of SJL/J mice. A significant decrease of YAC-1 cells apoptotic rate under radiation appeared after 4 weeks of culture.Therefore very small doses of gamma-irradiation are able to modify the cellular response. The main observations did not last with increasing time under irradiation, suggesting a transient adaptation of cells or organisms to this level of irradiation.     

Association of Sarcopenia and Gut Microbiota Composition in Older Patients with Advanced Chronic Kidney Disease,Investigation of the Interactions with Uremic Toxins,Inflammation and Oxidative Stress

Sarcopenia is a prevalent condition in chronic kidney disease (CKD). We determined gut microbiota (gMB) composition in CKD patients with or without sarcopenia. Furthermore, we investigated whether in these patients, there was any association between gMB, uremic toxins, inflammation and oxidative stress. We analyzed gMB composition, uremic toxins (indoxyl sulphate and p-cresyl sulphate), inflammatory cytokines (interleukin 10, tumor necrosis factor α, interleukin 6, interleukin 17, interleukin 12 p70, monocyte chemoattractant protein-1 and fetuin-A) and oxidative stress (malondialdehyde) of 64 elderly CKD patients (10 < eGFR < 45 mL/min/1.73 m², not on dialysis) categorized as sarcopenic and not-sarcopenic. Sarcopenia was defined according to European Working Group on Sarcopenia in Older People 2 criteria. Sarcopenic patients had a greater abundance of the Micrococcaceae and Verrucomicrobiaceae families and of Megasphaera, Rothia, Veillonella, Akkermansia and Coprobacillus genera. They had a lower abundance of the Gemellaceae and Veillonellaceae families and of Acidaminococcus and Gemella genera. GMB was associated with uremic toxins, inflammatory cytokines and MDA. However, uremic toxins, inflammatory cytokines and MDA were not different in sarcopenic compared with not-sarcopenic individuals, except for interleukin 10, which was higher in not-sarcopenic patients. In older CKD patients, gMB was different in sarcopenic than in not-sarcopenic ones. Several bacterial families and genera were associated with uremic toxins and inflammatory cytokines, although none of these latter substantially different in sarcopenic versus not-sarcopenic patients.