Punicalagin increases follicular activation, development and activity of superoxide dismutase 1, catalase, and glutathione peroxidase 1 in cultured bovine ovarian tissues.

Context The overproduction of reactive oxygen species (ROS) during in vitro culture of ovarian tissues impairs follicular development and survival. Aims To evaluate the effects of punicalagin on the development and survival of primordial follicles, stromal cell and collagen fibres, as well as on the levels of mRNA for nuclear factor erythroid 2-related factor 2 (NRF2 ), superoxide dismutase 1 (SOD1 ), catalase (CAT ), glutathione peroxidase 1 (GPX1 ) and perirredoxin 6 (PRDX6 ), and activity of antioxidant enzymes in cultured bovine ovarian tissues. Methods Bovine ovarian cortical tissues were cultured for 6days in α-MEM+ alone or with 1.0, 10.0, or 100.0µM punicalagin at 38.5°C with 5% CO2 . Follicle morphology and growth, stromal cell density, and collagen fibres were evaluated by classical histology, while the expression of mRNA was evaluated by real-time PCR. The activity of enzymes was analysed by the Bradford method. Key results Punicalagin improved follicle survival and development, reduced mRNA expression for SOD1 and CAT , but did not influence stromal cells or collagen fibres. Punicalagin (10.0µM) increased the levels of thiol and activity of SOD1, CAT , and GPX1 enzymes. Conclusions Punicalagin (10.0µM) promotes follicle survival and development and activates SOD1, CAT , and GPX1 enzymes in bovine ovarian tissues. Implications Punicalagin improves follicle development and survival in cultured ovarian tissues.

The discovery of acatalasemia (lack of catalase in the blood) and its significance in human genetics.

Catalase, a heme-containing antioxidant enzyme, was once considered essential for human survival. It is widely distributed in the human body and is particularly abundant in red blood cells. The term "acatalasemia" first appeared in the Proceedings of the Japan Academy in 1951, drawing global attention to families genetically deficient in catalase. This deficiency not only altered the significance of catalase but also played a pioneering role in human genetics during an era of limited genetic methodology. In this article, we examine the discovery of acatalasemia by an otolaryngologist during surgery on an 11-year-old girl. This remarkable journey led to epoch-making research spanning biochemistry, hematology, and human genetics.

Mitochondrial antioxidants abate SARS-COV-2 pathology in mice.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection inhibits mitochondrial oxidative phosphorylation (OXPHOS) and elevates mitochondrial reactive oxygen species (ROS, mROS) which activates hypoxia-inducible factor-1alpha (HIF-1α), shifting metabolism toward glycolysis to drive viral biogenesis but also causing the release of mitochondrial DNA (mtDNA) and activation of innate immunity. To determine whether mitochondrially targeted antioxidants could mitigate these viral effects, we challenged mice expressing human angiotensin-converting enzyme 2 (ACE2) with SARS-CoV-2 and intervened using transgenic and pharmacological mitochondrially targeted catalytic antioxidants. Transgenic expression of mitochondrially targeted catalase (mCAT) or systemic treatment with EUK8 decreased weight loss, clinical severity, and circulating levels of mtDNA; as well as reduced lung levels of HIF-1α, viral proteins, and inflammatory cytokines. RNA-sequencing of infected lungs revealed that mCAT and Eukarion 8 (EUK8) up-regulated OXPHOS gene expression and down-regulated HIF-1α and its target genes as well as innate immune gene expression. These data demonstrate that SARS-CoV-2 pathology can be mitigated by catalytically reducing mROS, potentially providing a unique host-directed pharmacological therapy for COVID-19 which is not subject to viral mutational resistance.

Natural variation in yeast reveals multiple paths for acquiring higher stress resistance.

BACKGROUND: Organisms frequently experience environmental stresses that occur in predictable patterns and combinations. For wild Saccharomyces cerevisiae yeast growing in natural environments, cells may experience high osmotic stress when they first enter broken fruit, followed by high ethanol levels during fermentation, and then finally high levels of oxidative stress resulting from respiration of ethanol. Yeast have adapted to these patterns by evolving sophisticated "cross protection" mechanisms, where mild 'primary' doses of one stress can enhance tolerance to severe doses of a different 'secondary' stress. For example, in many yeast strains, mild osmotic or mild ethanol stresses cross protect against severe oxidative stress, which likely reflects an anticipatory response important for high fitness in nature. RESULTS: During the course of genetic mapping studies aimed at understanding the mechanisms underlying natural variation in ethanol-induced cross protection against H2O2, we found that a key H2O2 scavenging enzyme, cytosolic catalase T (Ctt1p), was absolutely essential for cross protection in a wild oak strain. This suggested the absence of other compensatory mechanisms for acquiring H2O2 resistance in that strain background under those conditions. In this study, we found surprising heterogeneity across diverse yeast strains in whether CTT1 function was fully necessary for acquired H2O2 resistance. Some strains exhibited partial dispensability of CTT1 when ethanol and/or salt were used as mild stressors, suggesting that compensatory peroxidases may play a role in acquired stress resistance in certain genetic backgrounds. We leveraged global transcriptional responses to ethanol and salt stresses in strains with different levels of CTT1 dispensability, allowing us to identify possible regulators of these alternative peroxidases and acquired stress resistance in general. CONCLUSIONS: Ultimately, this study highlights how superficially similar traits can have different underlying molecular foundations and provides a framework for understanding the diversity and regulation of stress defense mechanisms.

Alleviation of H2O2 toxicity by extracellular catalases in the phycosphere of Microcystis aeruginosa.

High levels of environmental H2O2 represent a threat to many freshwater bacterial species, including toxic-bloom-forming Microcystis aeruginosa, particularly under high-intensity light conditions. The highest extracellular catalase activity-possessing Pseudoduganella aquatica HC52 was chosen among 36 culturable symbiotic isolates from the phycosphere in freshly collected M. aeruginosa cells. A zymogram for catalase activity revealed the presence of only one extracellular catalase despite the four putative catalase genes (katA1, katA2, katE, and srpA) identified in the newly sequenced genome (∼6.8 Mb) of P. aquatica HC52. Analysis of secreted catalase using liquid chromatography-tandem mass spectrometry was identified as KatA1, which lacks a typical signal peptide, although the underlying mechanism for its secretion is unknown. The expression of secreted KatA1 appeared to be induced in the presence of H2O2. Proteomic analysis also confirmed the presence of KatA1 inside the outer membrane vesicles secreted by P. aquatica HC52 following exposure to H2O2. High light intensities (> 100 µmol m-2 s-1) are known to kill catalase-less axenic M. aeruginosa cells, but the present study found that the presence of P. aquatica cells supported the growth of M. aeruginosa, while the extracellular catalases in supernatant or purified form also sustained the growth of M. aeruginosa under the same conditions. Our results suggest that the extracellular catalase secreted by P. aquatica HC52 enhances the tolerance of M. aeruginosa to H2O2, thus promoting the formation of M. aeruginosa blooms under high light intensities.

The hard life of an octopus embryo is seen through gene expression, energy metabolism, and its ability to neutralize radical oxygen species.

The reproductive process in Octopus maya was analyzed to establish the amount of reactive oxygen species that the embryos inherit from females, during yolk synthesis. At the same time, respiratory metabolism, ROS production, and the expression of some genes of the antioxidant system were monitored to understand the ability of embryos to neutralize maternal ROS and those produced during development. The results indicate that carbonylated proteins and peroxidized lipids (LPO) were transferred from females to the embryos, presumably derived from the metabolic processes carried out during yolk synthesis in the ovary. Along with ROS, females also transferred to embryos glutathione (GSH), a key element of the antioxidant defense system, thus facilitating the neutralization of inherited ROS and those produced during development. Embryos are capable of neutralizing ROS thanks to the early expression of genes such as catalase (CAT) and superoxide dismutase (SOD), which give rise to the synthesis of enzymes when the circulatory system is activated. Also, it was observed that the levels of the routine metabolic rate of embryos are almost as high as those of the maximum activity metabolism, which leads, on the one hand, to the elevated production of ROS and suggests that, at this stage of the life cycle in octopuses, energy production is maximum and is physically limited by the biological properties inherent to the structure of embryonic life (oxygen transfer through the chorion, gill surface, pumping capacity, etc.). Due to its role in regulating vascularization, a high expression of HIf-1A during organogenesis suggests that circulatory system development has begun in this phase of embryo development. The results indicate that the routine metabolic rate and the ability of O. maya embryos to neutralize the ROS are probably the maximum possible. Under such circumstances, embryos cannot generate more energy to combat the free radicals produced by their metabolism, even when environmental factors such as high temperatures or contaminants could demand excess energy.

Volatiles emitted by Pseudomonas aurantiaca ST-TJ4 trigger systemic plant resistance to Verticillium dahliae.

Verticillium dahliae is among the most devastating fungal pathogens, causing significant economic harm to agriculture and forestry. To address this problem, researchers have focused on eliciting systemic resistance in host plants through utilizing volatile organic compounds (VOCs) produced by biological control agents. Herein, we meticulously measured the quantity of V. dahliae pathogens in plants via RTqPCR, as well as the levels of defensive enzymes and pathogenesis-related (PR) proteins within plants. Finally, the efficacy of VOCs in controlling Verticillium wilt in cotton was evaluated. Following treatment with Pseudomonas aurantiaca ST-TJ4, the expression of specific VdEF1-α genes in cotton decreased significantly. The incidence and disease indices also decreased following VOC treatment. In cotton, the salicylic acid (SA) signal was strongly activated 24 h posttreatment; then, hydrogen peroxide (H2O2) levels increased at 48 h, and peroxidase (POD) and catalase (CAT) activities increased to varying degrees at different time points. The malondialdehyde (MDA) content and electrolyte leakage in cotton treated with VOCs were lower than those in the control group, and the expression levels of chitinase (CHI) and PR genes (PR10 and PR17), increased at various time points under the ST-TJ4 treatment. The activity of phenylalanine ammonia lyase (PAL) enzymes in cotton treated with VOCs was approximately 1.26 times greater than that in control plants at 24 h，while the contents of phenols and flavonoids increased significantly in the later stage. Additionally, 2-undecanone and 1-nonanol can induce a response in plants that enhances disease resistance. Collectively, these findings strongly suggest that VOCs from ST-TJ4 act as elicitors of plant defence and are valuable natural products for controlling Verticillium wilt.

The association between dietary, physical activity and the DNA methylation of PPARGC1A, HLA-DQA1 and ADCY3 in pregnant women with gestational diabetes mellitus: a nest case-control study.

BACKGROUND: Gestational diabetes mellitus (GDM) is associated with DNA methylation and lifestyle. The effects of DNA methylation on GDM, and the interaction between DNA methylation and lifestyle factors are not well elucidated. The objective of this study was to explore the association between GDM, DNA methylation and lifestyle factors. METHODS: A nest case-control design was performed. Sociodemographic data, dietary intake and daily physical activity information of pregnant women were collected. Bisulfate pyrosequencing was used to detect the DNA methylation level of PPARGC1A, HLA-DQA1, and ADCY3 genes. The differences of DNA methylation levels between the GDM group and the control group were compared. The correlation between clinical characteristics, dietary, physical activity and DNA methylation level was analyzed. RESULTS: A total of 253 pregnant women were enrolled, of which, 60 participants (GDM: 30; control: 30) were included in the final analysis. There were no significant differences in DNA methylation levels of six methylated sites between the two groups in this study (P > 0.05). Daily intake of potato and poultry were associated with DNA methylation level of the CpG 1 site of the ADCY3 gene in all participants and the control group (P < 0.05). Duration of folic acid intake before pregnancy was correlated with the methylation level of the CpG 1 site of the ADCY3 gene in all participants (r = 0.341, P = 0.04) and the control group (r = 0.431, P = 0.025). Daily oil intake was correlated with the methylation level of CpG 2 (r = 0.627, P = 0.016) and CpG 3 (r = 0.563, P = 0.036) of PPARGC1A in the GDM group. CONCLUSION: The association between the DNA methylation levels and GDM wasn't validated. There were associations between dietary and DNA methylation in pregnant women. A large-sample-sized and longitudinal study is warranted to further investigate the impacts of lifestyle on DNA methylation.

The Structural Biology of Catalase Evolution.

Catalases are essential enzymes for removal of hydrogen peroxide, enabling aerobic and anaerobic metabolism in an oxygenated atmosphere. Monofunctional heme catalases, catalase-peroxidases, and manganese catalases, evolved independently more than two billion years ago, constituting a classic example of convergent evolution. Herein, the diversity of catalase sequences is analyzed through sequence similarity networks, providing the context for sequence distribution of major catalase families, and showing that many divergent catalase families remain to be experimentally studied.

Isoniazid monoresistant tuberculosis treatment outcomes in Puducherry, South India - A mixed methods study.

SETTING: On a programmatic basis, a new regimen was introduced in the National Tuberculosis Elimination Programme for isoniazid monoresistant tuberculosis in a few states in India. OBJECTIVE: To describe the clinical attributes and treatment outcomes of isoniazid mono-resistant tuberculosis patients on the new 6-month levofloxacin-containing regimen in Puducherry, India. DESIGN: The study is designed as a convergent parallel mixed-methods study: a retrospective cohort study and a descriptive qualitative study. A total of 180 Hr-TB patient health records were reviewed, and in-depth interviews with 35 participants were conducted. (20 Hr-TB patients and 15 HCWs). RESULTS: Of the total 180 Hr-TB patients included, we documented unfavourable outcomes in 26.1% of cases, and the KatG gene mutation was the most common mutation observed (63.9%). A significant risk of unfavourable outcomes was associated with low adherence and positive sputum at the third-month culture report. In interviewing the stakeholders, major challenges observed were the increased pill burden, delay in diagnosis, shortage of drugs, and lack of staff. CONCLUSION: Hr-TB patients have difficulty in adhering to the 6-month levofloxacin regimen, with the need for rigorous early 3-month follow-up and assessment.

The transcription factor MhZAT10 enhances antioxidant capacity by directly activating the antioxidant genes MhMSD1, MhAPX3a and MhCAT1 in apple rootstock SH6 (Malus honanensis × M. domestica).

Stress tolerance in apple (Malus domestica) can be improved by grafting to a stress-tolerant rootstock, such as 'SH6' (Malus honanensis × M. domestica 'Ralls Genet'). However, the mechanisms of stress tolerance in this rootstock are unclear. In Arabidopsis (Arabidopsis thaliana), the transcription factor ZINC FINGER OF ARABIDOPSIS THALIANA 10 is a key component of plant tolerance to multiple abiotic stresses and positively regulates antioxidant enzymes. However, how reactive oxygen species are eliminated upon activation of ZINC FINGER OF ARABIDOPSIS THALIANA 10 in response to abiotic stress remains elusive. Here, we report that MhZAT10 in the rootstock SH6 directly activates the transcription of three genes encoding the antioxidant enzymes MANGANESE SUPEROXIDE DISMUTASE 1 (MhMSD1), ASCORBATE PEROXIDASE 3A (MhAPX3a) and CATALASE 1 (MhCAT1) by binding to their promoters. Heterologous expression in Arabidopsis protoplasts showed that MhMSD1, MhAPX3a and MhCAT1 localize in multiple subcellular compartments. Overexpressing MhMSD1, MhAPX3a or MhCAT1 in SH6 fruit calli resulted in higher superoxide dismutase, ascorbate peroxidase and catalase enzyme activities in their respective overexpressing calli than in those overexpressing MhZAT10. Notably, the calli overexpressing MhZAT10 exhibited better growth and lower reactive oxygen species levels under simulated osmotic stress. Apple SH6 plants overexpressing MhZAT10 in their roots via Agrobacterium rhizogenes-mediated transformation also showed enhanced tolerance to osmotic stress, with higher leaf photosynthetic capacity, relative water content in roots and antioxidant enzyme activity, as well as less reactive oxygen species accumulation. Overall, our study demonstrates that the transcription factor MhZAT10 synergistically regulates the transcription of multiple antioxidant-related genes and elevates reactive oxygen species detoxification.

Pepper catalase: a broad analysis of its modulation during fruit ripening and by nitric oxide.

Catalase is a major antioxidant enzyme located in plant peroxisomes that catalyzes the decomposition of H2O2. Based on our previous transcriptomic (RNA-Seq) and proteomic (iTRAQ) data at different stages of pepper (Capsicum annuum L.) fruit ripening and after exposure to nitric oxide (NO) enriched atmosphere, a broad analysis has allowed us to characterize the functioning of this enzyme. Three genes were identified, and their expression was differentially modulated during ripening and by NO gas treatment. A dissimilar behavior was observed in the protein expression of the encoded protein catalases (CaCat1-CaCat3). Total catalase activity was down-regulated by 50% in ripe (red) fruits concerning immature green fruits. This was corroborated by non-denaturing polyacrylamide gel electrophoresis, where only a single catalase isozyme was identified. In vitro analyses of the recombinant CaCat3 protein exposed to peroxynitrite (ONOO-) confirmed, by immunoblot assay, that catalase underwent a nitration process. Mass spectrometric analysis identified that Tyr348 and Tyr360 were nitrated by ONOO-, occurring near the active center of catalase. The data indicate the complex regulation at gene and protein levels of catalase during the ripening of pepper fruits, with activity significantly down-regulated in ripe fruits. Nitration seems to play a key role in this down-regulation, favoring an increase in H2O2 content during ripening. This pattern can be reversed by the exogenous NO application. While plant catalases are generally reported to be tetrameric, the analysis of the protein structure supports that pepper catalase has a favored quaternary homodimer nature. Taken together, data show that pepper catalase is down-regulated during fruit ripening, becoming a target of tyrosine nitration, which provokes its inhibition.

Mitochondria-targeted catalase induced cell malignant transformation by the downregulation of p53 protein stability via USP28/miR-200b/PP2A-Cα axis.

Antioxidants exert a paradoxical influence on cancer prevention. The latest explanation for this paradox is the different target sites of antioxidants. However, it remains unclear how mitochondria-targeted antioxidants trigger specific p53-dependent pathways in malignant transformation models. Our study revealed that overexpression of mitochondria-targeted catalase (mCAT) instigated such malignant transformation via mouse double minute 2 homolog (MDM2) -mediated p53 degradation. In mouse epithelial JB6 Cl41 cells, the stable expression of mCAT resulted in MDM2-mediated p53 degradation, unlike in catalase-overexpressed Cl41 cells. Further, we demonstrated that mCAT overexpression upregulated ubiquitin-specific protease 28 (USP28) expression, which in turn stabilized c-Jun protein levels. This alteration initiated the activation of the miR-200b promoter transcription activity and a subsequent increase in miR-200b expression. Furthermore, elevated miR-200b levels then promoted its binding to the 3'-untranslated region of protein phosphatase 2A catalytic subunit (PP2A-C) α-isoform mRNA, consequently resulting in PP2A-C protein downregulation. This cascade of events ultimately contributed to increased MDM2 phosphorylation and p53 protein degradation. Thus, the mCAT overexpression triggers MDM2/p53-dependent malignant transformation through USP28/miR-200b/PP2A-Cα pathway, which may provide a new information for understanding mitochondria-targeted antioxidants facilitate the progression to the tumorigenic state.

A chimeric membrane enzyme and an engineered whole-cell biocatalyst for efficient 1-alkene production.

Bioproduction of 1-alkenes from naturally abundant free fatty acids offers a promising avenue toward the next generation of hydrocarbon-based biofuels and green commodity chemicals. UndB is the only known membrane-bound 1-alkene-producing enzyme, with great potential for 1-alkene bioproduction, but the enzyme exhibits limited turnovers, thus restricting its widespread usage. Here, we explore the molecular basis of the limitation of UndB activity and substantially improve its catalytic power. We establish that the enzyme undergoes peroxide-mediated rapid inactivation during catalysis. To counteract this inactivation, we engineered a chimeric membrane enzyme by conjugating UndB with catalase that protected UndB against peroxide and enhanced its number of turnovers tremendously. Notably, our chimeric enzyme is the only example of a membrane enzyme successfully engineered with catalase. We subsequently constructed a whole-cell biocatalytic system and achieved remarkable efficiencies (up to 95%) in the biotransformation of a wide range of fatty acids (both aliphatic and aromatic) into corresponding 1-alkenes with numerous biotechnological applications.

Thymol increases primordial follicle activation, protects stromal cells, collagen fibers and down-regulates expression of mRNA for superoxide dismutase 1, catalase and periredoxin 6 in cultured bovine ovarian tissues.

This study aims to investigate the influence of thymol on primordial follicle growth and survival, as well as on collagen fibers and stromal cells density in bovine ovarian tissues cultured in vitro. The activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), the thiol levels and the expression of mRNAs for SOD1, CAT, periredoxin 6 (PRDX6) and GPX1 were also investigated. Ovarian cortical tissues were cultured in α-MEM+ alone or with thymol (400, 800, 1600 or 3200 µg/mL) for six days. Before and after culture, the tissues were processed for histological analysis to evaluate follicular activation, growth, morphology, ovarian stromal cell density and collagen fibers. The levels of mRNA for SOD1, CAT, GPX1 and PRDX6 were evaluated by real-time PCR. The results show that tissues cultured with thymol (400 and 800 µg/mL) had increased percentages of normal follicles, when compared to tissues cultured in other treatments. At concentrations of 400 and 800 µg/mL, thymol maintained the rate of normal follicles similar to the uncultured control. In addition, 400 µg/mL thymol increased follicle activation, collagen fibers and stromal cell density of when compared to tissues cultured in control medium. The presence of 800 µg/mL thymol in culture medium increased CAT activity, while 400 or 800 µg/mL thymol reduced mRNA levels for SOD1, CAT and PRDX6, but did not alter GPX1 expression. In conclusion, 400 µg/mL thymol increases primordial follicle activation, preserves stromal cells, collagen fibers, and down-regulates expression of mRNA for SOD1, CAT and PRDX6 in cultured bovine ovarian tissues.

Antioxidant and neurodevelopmental gene polymorphisms in prematurely born individuals influence hypoxia-related oxidative stress.

Preterm born (PTB) infants are at risk for injuries related to oxidative stress. We investigated the association between antioxidant and neurodevelopmental gene polymorphisms and oxidative stress parameters in PTB male young adults and their term-born counterparts at rest and during exercise. Healthy young PTB (N = 22) and full-term (N = 15) males underwent graded exercise tests in normobaric normoxic (FiO2 = 0.21) and hypoxic (FiO2 = 0.13) conditions. CAT rs1001179 was associated with decrease in nitrites in the whole group and in PTB individuals (P = 0.017 and P = 0.043, respectively). GPX1 rs1050450 was associated with decrease in ferric reducing antioxidant power in the whole group and in full-term individuals (P = 0.017 and P = 0.021, respectively). HIF1A rs11549465 was associated with decrease in nitrotyrosine and increase in malondialdehyde (P = 0.022 and P = 0.018, respectively). NOTCH4 rs367398 was associated with increase in advanced oxidation protein products and nitrites (P = 0.002 and P = 0.004, respectively) in hypoxia. In normoxia, NOTCH4 rs367398 was associated with increase in malondialdehyde in the whole group (P = 0.043). BDNF rs6265 was associated with decreased nitrites/nitrates in the whole group and in PTB individuals (P = 0.009 and P = 0.043, respectively). Polymorphisms in investigated genes and PTB might influence oxidative stress response after exercise in normoxic or hypoxic conditions far beyond the neonatal period in young male adults.

Protective effects of silymarin in glioblastoma cancer cells through redox system regulation.

BACKGROUND: Glioblastoma multiforme, a deadly form of brain tumor, is characterized by aggressive growth and poor prognosis. Oxidative stress, a disruption in the balance between antioxidants and oxidants, is a crucial factor in its pathogenesis. Silymarin, a flavonoid extracted from milk thistle, has shown therapeutic potential in inhibiting cancer cell growth, promoting apoptosis, and reducing inflammation. It also regulates oxidative stress. This study aims to investigate the regulatory effects of silymarin on oxidative stress parameters, especially the transcription factor Nrf2 and its related enzymes in GBM cancer cells, to develop a new anti-cancer compound with low toxicity. METHODS AND RESULTS: First, the cytotoxicity of silymarin on U-87 MG cells was investigated by MTT and the results showed an IC50 of 264.6 µM. Then, some parameters of the redox system were measured with commercial kits, and the obtained results showed that silymarin increased the activity of catalase and superoxide dismutase enzymes, as well as the total antioxidant capacity levels; while the malondialdehyde level that is an indicator of lipid peroxidation was decreased by this compound. The expression level of Nrf2 and HO-1 and glutaredoxin and thioredoxin enzymes were checked by real-time PCR method, and the expression level increased significantly after treatment. CONCLUSIONS: Our findings suggest that silymarin may exert its cytotoxic and anticancer effects by enhancing the Nrf2/HO-1 pathway through antioxidant mechanisms in U-87 MG cells.

N-acetylcysteine alleviates arsenic trioxide-induced reductions in hepatic catalase gene expression both in vitro and in vivo.

Arsenic trioxide (ATO), one of the oldest and most frequently used poisons, is well-known in forensic science for inducing hepatotoxicity. The regulation of peroxisomal antioxidative enzyme catalase (CAT) involves intricate mechanisms at both transcriptional and post-transcriptional levels. However, the molecular mechanisms underlying the regulation of CAT gene expression in hepatic cells remain elusive. Furthermore, the regulation of CAT gene expression evident in animals administered with ATO in vivo is not well-explored, although several studies have revealed ATO-induced reductions in CAT enzymatic activity in rat livers. In this study, we revealed ATO-dependent reductions in CAT gene expression in both rat liver and Huh-7 human hepatoma cells. Our results indicate that the decline in CAT enzymatic activity can be attributed, at least in part, to the downregulation of its gene expression. The ATO-induced reduction in CAT expression was concurrent with the reduction in peroxisome proliferator-activated receptor-gamma (PPARγ) coactivator (PGC)-1α and inactivation of PPARγ, both considered as positive regulators of CAT gene expression. Moreover, antioxidant N-acetylcysteine (NAC) demonstrated the capability to alleviate the downregulation of CAT gene expression both in vivo and in vitro. Additionally, NAC played a role in alleviating ATO-induced hepatotoxicity, potentially by mitigating the transcriptional downregulation of the CAT gene. Altogether, these results indicate that ATO exerts toxicity by inhibiting the antioxidant defense mechanism, which may be useful for forensic diagnosis of arsenic poisoning and clinical treatment of mitigating ATO-induced hepatotoxicity.

Biochemical and molecular evaluation of oxidative stress and mitochondrial damage in fruit fly exposed to carmoisine.

BACKGROUND: In today's world, appearance is an important factor in almost all areas of our lives. Therefore, it has become common to use dyes to color foods to make them look appetizing and visually appealing. However, food additives have negative effects on biochemical processes in cells at both high and low doses. METHODS AND RESULTS: This study investigated the effect of carmoisine, a commonly used food coloring, on oxidative stress and damage parameters in Drosophila melanogaster in terms of both enzymatic and gene expression. The change in mitochondrial DNA copy number (mtDNA-CN), a marker of oxidative stress, was also examined. When the data obtained were analyzed, it was observed that carmoisine caused a significant decrease in GSH levels depending on the increase in dose. SOD, CAT, GPx, and AChE enzyme activities and gene expression levels were also found to be significantly decreased. All groups also showed a significant decrease in mtDNA-CN. The effect of carmoisine on Drosophila melanogaster morphology was also investigated in our study. However, no significant change was observed in terms of morphological development in any group. CONCLUSIONS: When all the findings were evaluated together, it was observed that carmoisin triggered oxidative stress and these effects became more risky at high doses. Therefore, we believe that the consumer should be made more aware of the side effects of azo dyes in food and that the type and concentration of each substance added to food should be specified.

TNF-α promoter hypomethylation is frequent in oncopediatric patients who recovered from mucositis.

The aim of this study was to investigate the DNA methylation profile in genes encoding catalase (CAT) and superoxide dismutase (SOD3) enzymes, which are involved in oxidative stress mechanisms, and in genes encoding pro-inflammatory cytokines interleukin-6 (IL6) and tumor necrosis factor-alpha (TNF-α) in the oral mucosa of oncopediatric patients treated with methotrexate (MTX®). This was a cross-sectional observational study and the population comprised healthy dental patients (n = 21) and those with hematological malignancies (n = 64) aged between 5 and 19 years. Oral conditions were evaluated using the Oral Assessment Guide and participants were divided into 4 groups: 1- healthy individuals; 2- oncopediatric patients without mucositis; 3- oncopediatric patients with mucositis; 4- oncopediatric patients who had recovered from mucositis. Methylation of DNA from oral mucosal cells was evaluated using the Methylation-Specific PCR technique (MSP). For CAT, the partially methylated profile was the most frequent and for SOD3 and IL6, the hypermethylated profile was the most frequent, with no differences between groups. For TNF-α, the hypomethylated profile was more frequent in the group of patients who had recovered from mucositis. It was concluded that the methylation profiles of CAT, SOD3, and IL6 are common profiles for oral cells of children and adolescents and have no association with oral mucositis or exposure to chemotherapy with MTX®. Hypomethylation of TNF-α is associated with oral mucosal recovery in oncopediatric patients who developed oral mucositis during chemotherapy.