Psammaplin A and Its Analogs Attenuate Oxidative Stress in Neuronal Cells through Peroxisome Proliferator-Activated Receptor γ Activation.

Psammaplins are sulfur containing bromotyrosine alkaloids that have shown antitumor activity through the inhibition of class I histone deacetylases (HDACs). The cytotoxic properties of psammaplin A (1), the parent compound, are related to peroxisome proliferator-activated receptor γ (PPARγ) activation, but the mechanism of action of its analogs psammaplin K (2) and bisaprasin (3) has not been elucidated. In this study, the protective effects against oxidative stress of compounds 1-3, isolated from the sponge Aplysinella rhax, were evaluated in SH-SY5Y cells. The compounds improved cell survival, recovered glutathione (GSH) content, and reduced reactive oxygen species (ROS) release at nanomolar concentrations. Psammaplins restored mitochondrial membrane potential by blocking mitochondrial permeability transition pore opening and reducing cyclophilin D expression. This effect was mediated by the capacity of 1-3 to activate PPARγ, enhancing gene expression of the antioxidant enzymes catalase, nuclear factor E2-related factor 2 (Nrf2), and glutathione peroxidase. Finally, HDAC3 activity was reduced by 1-3 under oxidative stress conditions. This work is the first description of the neuroprotective activity of 1 at low concentrations and the mechanism of action of 2 and 3. Moreover, it links for the first time the previously described effects of 1 in HDAC3 and PPARγ signaling, opening a new research field for the therapeutic potential of this compound family.

Hypoxia exposure blunts angiogenic signaling and upregulates the antioxidant system in endothelial cells derived from elephant seals.

BACKGROUND: Elephant seals exhibit extreme hypoxemic tolerance derived from repetitive hypoxia/reoxygenation episodes they experience during diving bouts. Real-time assessment of the molecular changes underlying protection against hypoxic injury in seals remains restricted by their at-sea inaccessibility. Hence, we developed a proliferative arterial endothelial cell culture model from elephant seals and used RNA-seq, functional assays, and confocal microscopy to assess the molecular response to prolonged hypoxia. RESULTS: Seal and human endothelial cells exposed to 1% O2 for up to 6 h respond differently to acute and prolonged hypoxia. Seal cells decouple stabilization of the hypoxia-sensitive transcriptional regulator HIF-1α from angiogenic signaling. Rapid upregulation of genes involved in glutathione (GSH) metabolism supports the maintenance of GSH pools, and intracellular succinate increases in seal but not human cells. High maximal and spare respiratory capacity in seal cells after hypoxia exposure occurs in concert with increasing mitochondrial branch length and independent from major changes in extracellular acidification rate, suggesting that seal cells recover oxidative metabolism without significant glycolytic dependency after hypoxia exposure. CONCLUSIONS: We found that the glutathione antioxidant system is upregulated in seal endothelial cells during hypoxia, while this system remains static in comparable human cells. Furthermore, we found that in contrast to human cells, hypoxia exposure rapidly activates HIF-1 in seal cells, but this response is decoupled from the canonical angiogenesis pathway. These results highlight the unique mechanisms that confer extraordinary tolerance to limited oxygen availability in a champion diving mammal.

The effect of continuous long-term illumination with visible light in different spectral ranges on mammalian cells.

One of the biggest challenges in tissue engineering and regenerative medicine is to ensure oxygen supply of cells in the (temporary) absence of vasculature. With the vision to exploit photosynthetic oxygen production by microalgae, co-cultivated in close vicinity to oxygen-consuming mammalian cells, we are searching for culture conditions that are compatible for both sides. Herein, we investigated the impact of long-term illumination on mammalian cells which is essential to enable photosynthesis by microalgae: four different cell types-primary human fibroblasts, dental pulp stem cells, and osteoblasts as well as the murine beta-cell line INS-1-were continuously exposed to warm white light, red or blue light over seven days. We observed that illumination with red light has no adverse effects on viability, metabolic activity and growth of the cells whereas exposure to white light has deleterious effects that can be attributed to its blue light portion. Quantification of intracellular glutathione did not reveal a clear correlation of this effect with an enhanced production of reactive oxygen species. Finally, our data indicate that the cytotoxic effect of short-wavelength light is predominantly a direct effect of cell illumination; photo-induced changes in the cell culture media play only a minor role.

Exogenous Hemin enhances the antioxidant defense system of rice by regulating the AsA-GSH cycle under NaCl stress.

Abiotic stress caused by soil salinization remains a major global challenge that threatens and severely impacts crop growth, causing yield reduction worldwide. In this study, we aim to investigate the damage of salt stress on the leaf physiology of two varieties of rice (Huanghuazhan, HHZ, and Xiangliangyou900, XLY900) and the regulatory mechanism of Hemin to maintain seedling growth under the imposed stress. Rice leaves were sprayed with 5.0 µmol·L-1 Hemin or 25.0 µmol·L-1 ZnPP (Zinc protoporphyrin IX) at the three leaf and one heart stage, followed by an imposed salt stress treatment regime (50.0 mmol·L-1 sodium chloride (NaCl)). The findings revealed that NaCl stress increased antioxidant enzymes activities and decreased the content of nonenzymatic antioxidants such as ascorbate (AsA) and glutathione (GSH). Furthermore, the content of osmoregulatory substances like soluble proteins and proline was raised. Moreover, salt stress increased reactive oxygen species (ROS) content in the leaves of the two varieties. However, spraying with Hemin increased the activities of antioxidants such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) and accelerated AsA-GSH cycling to remove excess ROS. In summary, Hemin reduced the effect of salt stress on the physiological characteristics of rice leaves due to improved antioxidant defense mechanisms that impeded lipid peroxidation. Thus, Hemin was demonstrated to lessen the damage caused by salt stress.

Indole-3-carboxaldehyde alleviates acetaminophen-induced liver injury via inhibition of oxidative stress and apoptosis.

Drug-induced liver injury (DILI) occurs frequently and can be life-threatening. Increasing researches suggest that acetaminophen (APAP) overdose is a leading cause of drug-induced liver injury. Indole-3-carboxaldehyde (I3A) alleviates hepatic inflammation, fibrosis and atherosclerosis, suggesting a potential role in different disease development. However, the question of whether and how I3A protects against acetaminophen-induced liver injury remains unanswered. In this study, we demonstrated that I3A treatment effectively mitigates acetaminophen-induced liver injury. Serum alanine/aspartate aminotransferases (ALT/AST), liver malondialdehyde (MDA) activity, liver glutathione (GSH), and superoxide dismutase (SOD) levels confirmed the protective effect of I3A against APAP-induced liver injury. Liver histological examination provided further evidence of I3A-induced protection. Mechanistically, I3A reduced the expression of apoptosis-related factors and oxidative stress, alleviating disease symptoms. Finally, I3A treatment improved survival in mice receiving a lethal dose of APAP. In conclusion, our study demonstrates that I3A modulates hepatotoxicity and can be used as a potential therapeutic agent for DILI.

Neuroprotective Assessment of Betaine against Copper Oxide Nanoparticle-Induced Neurotoxicity in the Brains of Albino Rats: A Histopathological, Neurochemical, and Molecular Investigation.

Copper oxide nanoparticles (CuO-NPs) are commonly used metal oxides. Betaine possesses antioxidant and neuroprotective activities. The current study aimed to investigate the neurotoxic effect of CuO-NPs on rats and the capability of betaine to mitigate neurotoxicity. Forty rats; 4 groups: group I a control, group II intraperitoneally CuO-NPs (0.5 mg/kg/day), group III orally betaine (250 mg/kg/day) and CuO-NPs, group IV orally betaine for 28 days. Rats were subjected to neurobehavioral assessments. Brain samples were processed for biochemical, molecular, histopathological, and immunohistochemical analyses. Behavioral performance of betaine demonstrated increasing locomotion and cognitive abilities. Group II exhibited significantly elevated malondialdehyde (MDA), overexpression of interleukin-1 beta (IL-1ß), and tumor necrosis factor-alpha (TNF-α). Significant decrease in glutathione (GSH), and downregulation of acetylcholine esterase (AChE), nuclear factor erythroid 2-like protein 2 (Nrf-2), and superoxide dismutase (SOD). Histopathological alterations; neuronal degeneration, pericellular spaces, and neuropillar vacuolation. Immunohistochemically, an intense immunoreactivity is observed against IL-1ß and glial fibrillary acidic protein (GFAP). Betaine partially neuroprotected against CuO-NPs associated alterations. A significant decrease at MDA, downregulation of IL-1ß, and TNF-α, a significant increase at GSH, and upregulation of AChE, Nrf-2, and SOD. Histopathological alterations partially ameliorated. Immunohistochemical intensity of IL-1ß and GFAP reduced. It is concluded that betaine neuroprotected against most of CuO-NP neurotoxic effects through antioxidant and cell redox system stimulating efficacy.

Revealing the Ferroptotic Phenotype of Medulloblastoma.

The interaction of iron and oxygen is an integral part of the development of life on Earth. Nonetheless, this unique chemistry continues to fascinate and puzzle, leading to new biological ventures. In 2012, a Columbia University group recognized this interaction as a central event leading to a new type of regulated cell death named "ferroptosis." The major feature of ferroptosis is the accumulation of lipid hydroperoxides due to (1) dysfunctional antioxidant defense and/or (2) overwhelming oxidative stress, which most frequently coincides with increased content of free labile iron in the cell. This is normally prevented by the canonical anti-ferroptotic axis comprising the cystine transporter xCT, glutathione (GSH), and GSH peroxidase 4 (GPx4). Since ferroptosis is not a programmed type of cell death, it does not involve signaling pathways characteristic of apoptosis. The most common way to prove this type of cell death is by using lipophilic antioxidants (vitamin E, ferrostatin-1, etc.) to prevent it. These molecules can approach and detoxify oxidative damage in the plasma membrane. Another important aspect in revealing the ferroptotic phenotype is detecting the preceding accumulation of lipid hydroperoxides, for which the specific dye BODIPY C11 is used. The present manuscript will show how ferroptosis can be induced in wild-type medulloblastoma cells by using different inducers: erastin, RSL3, and iron-donor. Similarly, the xCT-KO cells that grow in the presence of NAC, and which undergo ferroptosis once NAC is removed, will be used. The characteristic "bubbling" phenotype is visible under the light microscope within 12-16 h from the moment of ferroptosis triggering. Furthermore, BODIPY C11 staining followed by FACS analysis to show the accumulation of lipid hydroperoxides and consequent cell death using the PI staining method will be used. To prove the ferroptotic nature of cell death, ferrostatin-1 will be used as a specific ferroptosis-preventing agent.

Protective effects of esculetin against doxorubicin-induced toxicity correlated with oxidative stress in rat liver: In vivo and in silico studies.

Doxorubicin (DOX) is widely used in cancer treatment but the dose-related toxicity of DOX on organs including the liver limit its use. Therefore, there is great interest in combining DOX with natural compounds with antioxidant properties to reduce toxicity and increase drug efficacy. Esculetin is a natural coumarin derivative with biological properties encompassing anti-inflammatory and antioxidant activities. In light of these properties, this study was meticulously crafted to investigate the potential of esculetin in preventing doxorubicin (DOX)-induced hepatotoxicity in Sprague-Dawley rats. The rats were divided into a total of six groups: control group, DOX group (administered DOX at a cumulative dose of 5 mg/kg intraperitoneally every other day for 2 weeks), E50 group (administered 50 mg/kg of esculetin intraperitoneally every day), E100 group (administered 100 mg/kg of esculetin intraperitoneally every day) and combined groups (DOX + E50 and DOX + E100) in which esculetin was administered together with DOX. The treatments, both with DOX alone and in combination with E50, manifested a reduction in catalase (CAT mRNA) levels in comparison to the control group. Notably, the enzymatic activities of superoxide dismutase (SOD), CAT, and glutathione peroxidase (GPx) witnessed significant decreases in the liver of rats treated with DOX. Moreover, DOX treatment induced a statistically significant elevation in malondialdehyde (MDA) levels, coupled with a concurrent decrease in glutathione (GSH) levels. Additionally, molecular docking studies were conducted. However, further studies are needed to confirm the hepatoprotective properties of esculetin and to precisely elucidate its mechanisms of action.

Total transcriptome response for tyrosol exposure in Aspergillus nidulans.

Although tyrosol is a quorum-sensing molecule of Candida species, it has antifungal activity at supraphysiological concentrations. Here, we studied the effect of tyrosol on the physiology and genome-wide transcription of Aspergillus nidulans to gain insight into the background of the antifungal activity of this compound. Tyrosol efficiently reduced germination of conidia and the growth on various carbon sources at a concentration of 35 mM. The growth inhibition was fungistatic rather than fungicide on glucose and was accompanied with downregulation of 2199 genes related to e.g. mitotic cell cycle, glycolysis, nitrate and sulphate assimilation, chitin biosynthesis, and upregulation of 2250 genes involved in e.g. lipid catabolism, amino acid degradation and lactose utilization. Tyrosol treatment also upregulated genes encoding glutathione-S-transferases (GSTs), increased specific GST activities and the glutathione (GSH) content of the cells, suggesting that A. nidulans can detoxify tyrosol in a GSH-dependent manner even though this process was weak. Tyrosol did not induce oxidative stress in this species, but upregulated "response to nutrient levels", "regulation of nitrogen utilization", "carbon catabolite activation of transcription" and "autophagy" genes. Tyrosol may have disturbed the regulation and orchestration of cellular metabolism, leading to impaired use of nutrients, which resulted in growth reduction.

In vitro study on the competitive reactions between arsenite and selenite with glutathione.

Exposure to arsenic can cause various biological effects by increasing the production of reactive oxygen species (ROS). Selenium acts as a beneficial element by regulating ROS and limiting heavy metal uptake and translocation. There are studies on the interactive effects of As and Se in plants, but the antagonistic and synergistic effects of these elements based on their binding to glutathione (GSH) molecules have not been studied yet. In this study, we aimed to investigate the antagonistic or synergistic effects of As and Se on the binding mechanism of Se and As with GSH at pH 3.0, 5.0, or 6.5. The interaction of As and Se in Se(SG)2 + As(III) or As(SG)3 + Se(IV) binary systems and As(III) + Se(IV) + GSH ternary system were examined depending on their ratios via liquid chromatography diode array detector/electrospray mass spectrometry (LC-DAD/MS) and liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). The results showed that the formation of As(GS)3 was not detected in the As(III) + Se(SG)2 binary system, indicating that As(III) did not affect the stability of Se(SG)2 complex antagonistically. However, in the Se(IV) + As(SG)3 binary system, the addition of Se(IV) to As(SG)3 affected the stability of As(SG)3 antagonistically. Se(IV) reacted with GSH, disrupting the As(SG)3 complex, and consequently, Se(SG)2 formation was measured using LC-MS/DAD. In the Se(IV) + GSH + As(III) ternary system, Se(SG)2 formation was detected upon mixing As(III), Se(IV), and GSH. The increase in the concentration of As(III) did not influence the stability of the Se(SG)2 complex. Additionally, Se(IV) has a higher affinity than As(III) to the GSH, regardless of the pH of the solution. In both binary and ternary systems, the formation of the by-product glutathione trisulfide (GSSSG) was detected using LC-ESI-MS/MS.

A gold speciation that adds a second layer to synergistic gold-copper toxicity in Cupriavidus metallidurans.

The metal-resistant bacterium Cupriavidus metallidurans occurs in metal-rich environments. In auriferous soils, the bacterium is challenged by a mixture of copper ions and gold complexes, which exert synergistic toxicity. The previously used, self-made Au(III) solution caused a synergistic toxicity of copper and gold that was based on the inhibition of the CupA-mediated efflux of cytoplasmic Cu(I) by Au(I) in this cellular compartment. In this publication, the response of the bacterium to gold and copper was investigated by using a commercially available Au(III) solution instead of the self-made solution. The new solution was five times more toxic than the previously used one. Increased toxicity was accompanied by greater accumulation of gold atoms by the cells. The contribution of copper resistance determinants to the commercially available Au(III) solution and synergistic gold-copper toxicity was studied using single- and multiple-deletion mutants. The commercially available Au(III) solution inhibited periplasmic Cu(I) homeostasis, which is required for the allocation of copper ions to copper-dependent proteins in this compartment. The presence of the gene for the periplasmic Cu(I) and Au(I) oxidase, CopA, decreased the cellular copper and gold content. Transcriptional reporter gene fusions showed that up-regulation of gig, encoding a minor contributor to copper resistance, was strictly glutathione dependent. Glutathione was also required to resist synergistic gold-copper toxicity. The new data indicated a second layer of synergistic copper-gold toxicity caused by the commercial Au(III) solution, inhibition of the periplasmic copper homeostasis in addition to the cytoplasmic one.IMPORTANCEWhen living in auriferous soils, Cupriavidus metallidurans is not only confronted with synergistic toxicity of copper ions and gold complexes but also by different gold species. A previously used gold solution made by using aqua regia resulted in the formation of periplasmic gold nanoparticles, and the cells were protected against gold toxicity by the periplasmic Cu(I) and Au(I) oxidase CopA. To understand the role of different gold species in the environment, another Au(III) solution was commercially acquired. This compound was more toxic due to a higher accumulation of gold atoms by the cells and inhibition of periplasmic Cu(I) homeostasis. Thus, the geo-biochemical conditions might influence Au(III) speciation. The resulting Au(III) species may subsequently interact in different ways with C. metallidurans and its copper homeostasis system in the cytoplasm and periplasm. This study reveals that the geochemical conditions may decide whether bacteria are able to form gold nanoparticles or not.

Edible wild plants, chicory and purslane, alleviated diabetic testicular dysfunction, and insulin resistance via suppression 8OHdg and oxidative stress in rats.

Testicular dysfunction is a prevalent health problem frequently reported in individuals with diabetes mellitus (DM). Oxidative-inflammatory reactions, hormonal and spermatic abnormalities often accompany this illness. Herbal remedies "particularly wild plants" including chicory (Chicorium Intybus) and purslane (Portulaca Oleracea) are emerging as popular agents for people dealing with these issues due to their ability to act as antioxidants, reduce inflammation, and exhibit antidiabetic effects. According to the collected data, the daily administration of chicory (Ch) seed-extract (250 mg/kg) or purslane (Pu) seed-extract (200 mg/kg) to streptozotocin (STZ)-induced diabetic rats (50 mg/kg) for 30 days resulted in the normalization of fasting blood glucose (FBG), serum fructosamine, insulin levels, and insulin resistance (HOMA-IR), as well as reducing lipid peroxidation end-product malondialdehyde (MDA) level, aldehyde oxidase (AO) and xanthene oxidase (XO) activities. While caused a considerable improvement in glutathione (GSH) content, superoxide dismutase (SOD), catalase (CAT) activity, and total antioxidant capacity (TAC) when compared to diabetic rats. Ch and Pu extracts had a substantial impact on testicular parameters including sperm characterization, testosterone level, vimentin expression along with improvements in body and testis weight. They also mitigated hyperlipidemia by reducing total lipids (TL), total cholesterol (TC) levels, and low-density lipoprotein cholesterol (LDL-C), while increasing high-density lipoprotein cholesterol (HDL-C). Furthermore, oral administration of either Ch or Pu notably attuned the elevated proinflammatory cytokines as tumor necrotic factor (TNF-α), C-reactive protein (CRP), and Interleukin-6 (IL-6) together with reducing apoptosis and DNA damage. This was achieved through the suppression of DNA-fragmentation marker 8OHdG, triggering of caspase-3 immuno-expression, and elevation of Bcl-2 protein. The histological studies provided evidence supporting the preventive effects of Ch and Pu against DM-induced testicular dysfunction. In conclusion, Ch and Pu seed-extracts mitigate testicular impairment during DM due to their antihyperglycemic, antilipidemic, antioxidant, anti-inflammatory, and antiapoptotic properties.

Effect of levetiracetam on DNA oxidation and glutathione content in a temporal lobe epilepsy model.

Levetiracetam (LEV) is a drug commonly used as an anticonvulsant. However, recent evidence points to a possible role as an antioxidant. We previously demonstrated the antioxidant properties of LEV by significantly increasing catalase and superoxide dismutase activities and decreasing the hydrogen peroxide (H2O2) levels in the hippocampus of rats with temporal lobe epilepsy (TLE) showing scavenging properties against the hydroxyl radical. The aim of the present work was to evaluate, the effect of LEV on DNA oxidation, by determining 8­hydroxy­2­deoxyguanosine (8­OHdG) levels, and glutathione content, through reduced (GSH) and oxidized (GSSG) glutathione levels, in the hippocampus of rats with TLE. Male Wistar rats were assigned to the control (CTRL), CTRL+LEV, epileptic (EPI) and EPI+LEV groups. TLE was induced using the lithium­pilocarpine model. Thirteen weeks after TLE induction, LEV was administered for one week through osmotic pumps implanted subcutaneously. The determination of 8­OHdG, GSH and GSSG levels were measured using spectrophotometric methods. We showed that LEV alone significantly increased 8­OHdG and GSSG levels in the hippocampus of control rats compared to those in epileptic condition. No significant differences in GSH levels were observed. LEV could induce changes in the hippocampus increasing DNA oxidation and GSSG levels under nonepileptic condition but not protecting against the mitochondrial dysfunction observed in TLE probably by mechanisms related to changes in chromatin structure, neuroinflammation and alterations in redox components.

The ameliorating effect of Rutin on hepatotoxicity and inflammation induced by the daily administration of vortioxetine in rats.

BACKGROUND: Vortioxetine (VORTX) is a potent and selective type of selective serotonin reuptake inhibitor (SSRI) that is mainly prescribed for treating major depression along with mood disorders as the first drug of choice. Limited previous findings have indicated evidence of liver injury and hepatotoxicity associated with daily VORTX treatment. Rutin (RUT), which is known for its antioxidant properties, has demonstrated several beneficial health actions, including hepatoprotection. Therefore the current study aimed to evaluate and assess the ameliorative effect of RUT against the hepatotoxic actions of daily low and high-dose VORTX administration. METHODS: The experimental design included six groups of rats, each divided equally. Control, rats exposed to RUT (25 mg/kg), rats exposed to VORTX (28 mg/kg), rats exposed to VORTX (28 mg/kg) + RUT (25 mg/kg), rats exposed to VORTX (80 mg/kg), and rats exposed to VORTX (80 mg/kg) + RUT (25 mg/kg). After 30 days from the daily exposure period, assessments were conducted for serum liver enzyme activities, hepatotoxicity biomarkers, liver antioxidant endogenous enzymes, DNA fragmentation, and histopathological studies of liver tissue. RESULTS: Interestingly, the risk of liver damage and hepatotoxicity related to VORTX was attenuated by the daily co-administration of RUT. Significant improvements were observed among all detected liver functions, oxidative stress, and inflammatory biomarkers including aspartate aminotransferase (AST), alanine transaminase (ALT), lactate dehydrogenase (LDH), albumin, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), glutathione S-transferase (GST), total protein, acid phosphatase, N-Acetyl-/ß-glucosaminidase (ß-NAG), ß-Galactosidase (ß-Gal), alpha-fetoprotein (AFP), caspase 3, and cytochrom-C along with histopathological studies, compared to the control and sole RUT group. CONCLUSION: Thus, RUT can be considered a potential and effective complementary therapy in preventing hepatotoxicity and liver injury induced by the daily or prolonged administration of VORTX.

Protective role of citronellol on antioxidant enzymes and oxidative damage induced by gentamicin in experimental nephrotoxic rats.

BACKGROUND: Gentamicin leads to nephrotoxicity with increasing oxidative stress. In the present research the role of citronellol on oxidative damage induced by gentamicin in nephrotoxic rats was evaluated. METHODS AND RESULTS: Forty-twomale Wistar rats were randomly divided into seven equal groups; healthy control, gentamicin, DMSO, citronellol 50, citronellol 100, citronellol 200 and vitamin E. The animals were anesthetized after 12 days of treatment. Kidney and serum samples were received for biochemical, histological changes, and gene expression assessments. The levels of serum glutathione (GSH), serum and kidney glutathione peroxidase (GPX) and the expression of GPX gene against gentamicin group were increased in citronellol treatment groups. The levels of serum and kidney malondialdehyde (MDA), urine protein, serum creatinine and the gene expression of inflammatory factors including tumor necrosis factor-alpha (TNF-α) and Interleukin 6 (IL-6) against gentamicin group were decreased in these groups. Moreover, recuperation in histological alterations was shown in three groups receiving citronellol compared to the gentamicin group. CONCLUSIONS: Citronellol with its antioxidant and anti-inflammatory properties can decrease kidney damage caused by nephrotoxicity induced by gentamicin.

Tempol alleviates acute lung injury by affecting glutathione synthesis through Nrf2 and inhibiting ferroptosis in lung epithelial cells.

As a life-threatening disease, acute lung injury (ALI) may progress to chronic pulmonary fibrosis. For the treatment of lung injury, Tempol is a superoxide dismutase mimetic and intracellular redox agent that can be a potential drug. This study investigated the regulatory mechanism of Tempol in the treatment of ALI. A mouse model of ALI was established, and HE staining was used to examine histomorphology. The CCK-8 assay was used to measure cell viability, and oxidative stress was assessed by corresponding kits. Flow cytometry and dichlorodihydrofluorescein diacetate staining assays were used to detect reactive oxygen species (ROS) levels. Protein expression levels were measured by Western blot analysis and ELISA. Pulmonary vascular permeability was used to measure the lung wet/dry weight ratio. The level of oxidative stress was increased in ALI mice, and the level of ferroptosis was upregulated. Tempol inhibited this effect and alleviated ALI. The administration of Tempol alleviated the pathological changes in ALI, inhibited pulmonary vascular permeability, and improved lung injury in ALI mice. The upregulation of genes essential for glutathione (GSH) metabolism induced by lipopolysaccharide (LPS) was inhibited by Tempol. In addition, nuclear factor-related factor 2 (Nrf2) is activated by Tempol therapy to regulate the de novo synthesis pathway of GSH, thereby alleviating LPS-induced lung epithelial cell damage. The results showed that Tempol alleviated ALI by activating the Nrf2 pathway to inhibit oxidative stress and ferroptosis in lung epithelial cells. In conclusion, this study demonstrates that Tempol alleviates ALI by inhibiting ferroptosis in lung epithelial cells through the effect of Nrf2 on GSH synthesis.

Comprehensive Transcriptome Profiling of Antioxidant Activities by Glutathione in Human HepG2 Cells.

Glutathione (GSH) has long been recognised for its antioxidant and detoxifying effects on the liver. The hepatoprotective effect of GSH involves the activation of antioxidative systems such as NRF2; however, details of the mechanisms remain limited. A comparative analysis of the biological events regulated by GSH under physiological and oxidative stress conditions has also not been reported. In this study, DNA microarray analysis was performed with four experiment arms including Control, GSH, hydrogen peroxide (HP), and GSH + HP treatment groups. The GSH-treated group exhibited a significant upregulation of genes clustered in cell proliferation, growth, and differentiation, particularly those related to MAPK, when compared with the Control group. Additionally, liver functions such as alcohol and cholesterol metabolic processes were significantly upregulated. On the other hand, in the HP-induced oxidative stress condition, GSH (GSH + HP group) demonstrated a significant activation of cell proliferation, cell cycle, and various signalling pathways (including TGFß, MAPK, PI3K/AKT, and HIF-1) in comparison to the HP group. Furthermore, several disease-related pathways, such as chemical carcinogenesis-reactive oxygen species and fibrosis, were significantly downregulated in the GSH + HP group compared to the HP group. Collectively, our study provides a comprehensive analysis of the effects of GSH under both physiological and oxidative stress conditions. Our study provides essential insights to direct the utilisation of GSH as a supplement in the management of conditions associated with oxidative stress.

Validation of Salamander Dermal Mucus Swabs as a Novel, Nonlethal Approach for Amphibian Metabolomics and Glutathione Analysis Following Pesticide Exposure.

Evaluating biomarkers of stress in amphibians is critical to conservation, yet current techniques are often destructive and/or time-consuming, which limits ease of use. In the present study, we validate the use of dermal swabs in spotted salamanders (Ambystoma maculatum) for biochemical profiling, as well as glutathione (GSH) stress response following pesticide exposure. Thirty-three purchased spotted salamanders were acclimated to laboratory conditions at Washington College (Chestertown, MD, USA) for 4 weeks. Following acclimation, salamanders were randomly sorted into three groups for an 8-h pesticide exposure on soil: control with no pesticide, 2,4-dichlorophenoxyacetic acid (2,4-D), or chlorpyrifos. Before and after exposure, mucus samples were obtained by gently rubbing a polyester-tipped swab 50 times across the ventral and dorsal surfaces. Salamanders were humanely euthanized and dissected to remove the brain for acetylcholinesterase and liver for GSH and hepatic metabolome analyses, and a whole-body tissue homogenate was used for pesticide quantification. Levels of GSH were present in lower quantities on dermal swabs relative to liver tissues for chlorpyrifos, 2,4-D, and control treatments. However, 2,4-D exposures demonstrated a large effect size increase for GSH levels in livers (Cohen's d = 0.925, p = 0.036). Other GSH increases were statistically insignificant, and effect sizes were characterized as small for 2,4-D mucosal swabs (d = 0.36), medium for chlorpyrifos mucosal swabs (d = 0.713), and negligible for chlorpyrifos liver levels (d = 0.012). The metabolomics analyses indicated that the urea cycle, alanine, and glutamate metabolism biological pathways were perturbed by both sets of pesticide exposures. Obtaining mucus samples through dermal swabbing in amphibians is a viable technique for evaluating health in these imperiled taxa. Environ Toxicol Chem 2024;43:1126-1137. © 2024 SETAC.

Systemic and strict regulation of the glutathione redox state in mitochondria and cytosol is needed for zebrafish ontogeny.

BACKGROUND: Redox control seems to be indispensable for proper embryonic development. The ratio between glutathione (GSH) and its oxidized disulfide (GSSG) is the most abundant cellular redox circuit. METHODS: We used zebrafish harboring the glutaredoxin 1-redox sensitive green fluorescent protein (Grx1-roGFP) probe either in mitochondria or cytosol to test the hypothesis that the GSH:GSSG ratio is strictly regulated through zebrafish embryogenesis to sustain the different developmental processes of the embryo. RESULTS: Following the GSSG:GSH ratio as a proxy for the GSH-dependent reduction potential (EhGSH) revealed increasing mitochondrial and cytosolic EhGSH during cleavage and gastrulation. During organogenesis, cytosolic EhGSH decreased, while that of mitochondria remained high. The similarity between EhGSH in brain and muscle suggests a central regulation. Modulation of GSH metabolism had only modest effects on the GSSG:GSH ratios of newly hatched larvae. However, inhibition of GSH reductase directly after fertilization led to dead embryos already 10 h later. Exposure to the emerging environmental pollutant Perfluorooctane Sulfonate (PFOS) disturbed the apparent regulated EhGSH as well. CONCLUSIONS: Mitochondrial and cytosolic GSSG:GSH ratios are almost identical in different organs during zebrafish development indicating that the EhGSH might follow H2O2 levels and rather indirectly affect specific enzymatic activities needed for proper embryogenesis. GENERAL SIGNIFICANCE: Our data confirm that vertebrate embryogenesis depends on strictly regulated redox homeostasis. Disturbance of the GSSG:GSH circuit, e.g. induced by environmental pollution, leads to malformation and death.

IL-1α facilitates GSH synthesis to counteract oxidative stress in oral squamous cell carcinoma under glucose-deprivation.

Understanding the intrinsic mechanisms underpinning cancer metabolism and therapeutic resistance is of central importance for effective nutrition-starvation therapies. Here, we report that Interleukin 1A (IL1A) mRNA and IL-1α protein facilitate glutathione (GSH) synthesis to counteract oxidative stress and resistance against nutrition-starvation therapy in oral squamous cell carcinoma (OSCC). The expression of IL1A mRNA was elevated in the case of OSCC associated with unfavorable clinical outcomes. Both IL1A mRNA and IL-1α protein expression were increased under glucose-deprivation in vitro and in vivo. The transcription of IL1A mRNA was regulated in an NRF2-dependent manner in OSCC cell lines under glucose-deprivation. Moreover, the IL-1α conferred resistance to oxidative stress via GSH synthesis in OSCC cell lines. The intratumoral administration of siRNAs against IL1A mRNA markedly reversed GSH production and sensitized OSCC cells to Anlotinib in HN6 xenograft models. Overall, the current study demonstrates novel evidence that the autocrine IL-1α favors endogenous anti-oxidative process and confers therapeutic resistance to nutrition-starvation in OSCCs.