Spatially regulated oxidative stress responses during chlorotic symptom development in Pontederia crassipes exposed to clomazone.

IntroductionHemorrhage (i.e., massive blood loss) induces an oxidative stress and inflammatory response that can persist even following hemostasis and resuscitation. These responses can result in tissue and organ damage if therapeutic inventions are delayed. Pre‐menopausal females exhibit a survival advantage following hemorrhage compared to males of a similar age. The role of oxidative stress and inflammation on increased survival from blood loss in young females is under investigation. Examining the potential mechanisms underpinning this survival advantage following hemorrhage may facilitate the development of sex‐specific therapies. In our laboratory, we utilize lower body negative pressure (LBNP) to simulate blood loss in conscious human subjects. In this study, we hypothesized that young males would elicit a greater oxidative stress and inflammatory response compared to young females, both during and after a simulated hemorrhage via LBNP.MethodsYoung, healthy human subjects (10F; 10M) participated in a stepwise‐LBNP protocol to presyncope. Stroke volume was estimated via finger photoplethysmography as a marker of central hypovolemia (indexed to body surface area). Venous blood samples were collected at baseline, at the onset of presyncope, and 60‐min into recovery (i.e., following “resuscitation”). The oxidative stress response was assessed via measurement of circulating F2‐Isoprostanes (F2‐IsoP) using gas chromatography‐negative ion chemical ionization‐mass spectrometry. The inflammatory response was assessed via measurement of circulating interleukin (IL)‐6 and IL‐10 using a MSD® Multiplex assay. Unpaired t‐tests were used to compare LBNP tolerance and stroke volume responses between male and female subjects. Two factor (time and sex) linear mixed model analyses with repeated measures were performed for all other comparisons, followed by Holm‐corrected post‐hoc tests. All data are represented as mean ± SE.ResultsLBNP tolerance time was similar between male and female subjects (Males, 1592 ± 124 s vs. Females, 1437 ± 113 s; P=0.37), and stroke volume index decreased by a similar magnitude at presyncope (Males, −50.2 ± 6.3% vs. Females, −49.4 ± 3.2%; P = 0.87). There was no effect of time or sex on [F2‐IsoP] or on the %Δ [F2‐IsoP] during or after LBNP (P ≥ 0.12). However, male subjects exhibited a greater increase in both the %Δ [IL‐6] and %Δ [IL‐10] compared to female subjects at the 60‐min recovery time point (IL‐6: Males, 101.4 ± 138.9% vs. Females, 12.3 ± 34.0%; P = 0.06. IL‐10: Males, 71.1 ± 133.3% vs. Females, −2.2 ± 11.8%; P = 0.06).ConclusionThese data suggest that there may be a sex difference in the inflammatory response to blood loss and subsequent fluid resuscitation. Future clinical studies should continue to explore sex differences in inflammatory responses to actual blood loss, and tailor therapeutic interventions accordingly.Support or Funding InformationWilliam and Ella Owens Medical Research Foundation

BackgroundIsothiocyanates (ITCs) are degradation products of the plant secondary metabolites glucosinolates (GSLs) and are known to affect human health as well as plant herbivores and pathogens. To investigate the processes engaged in plants upon exposure to isothiocyanate we performed a genome scale transcriptional profiling of Arabidopsis thaliana at different time points in response to an exogenous treatment with allyl-isothiocyanate.ResultsThe treatment triggered a substantial response with the expression of 431 genes affected (P < 0.05 and log2 ≥ 1 or ≤ -1) already after 30 min and that of 3915 genes affected after 9 h of exposure, most of the affected genes being upregulated. These are involved in a considerable number of different biological processes, some of which are described in detail: glucosinolate metabolism, sulphate uptake and assimilation, heat stress response, oxidative stress response, elicitor perception, plant defence and cell death mechanisms.ConclusionExposure of Arabidopsis thaliana to vapours of allyl-isothiocyanate triggered a rapid and substantial transcriptional response affecting numerous biological processes. These include multiple stress stimuli such as heat stress response and oxidative stress response, cell death and sulphur secondary defence metabolism. Hence, effects of isothiocyanates on plants previously reported in the literature were found to be regulated at the gene expression level. This opens some avenues for further investigations to decipher the molecular mechanisms underlying the effects of isothiocyanates on plants.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-3039-x) contains supplementary material, which is available to authorized users.

Hypoxia-Associated Effects on Reactive Oxygen Species Generation by Human Acute Myeloid Leukemia Cells

Prophylactic creatine treatment may reduce hypoxic brain injury due to its ability to sustain intracellular ATP levels thereby reducing oxidative and metabolic stress responses during oxygen deprivation. Using microdialysis, we investigated the real‐time in vivo effects of fetal creatine supplementation on cerebral metabolism following acute in utero hypoxia caused by umbilical cord occlusion (UCO). Fetal sheep (118 days’ gestational age (dGA)) were implanted with an inflatable Silastic cuff around the umbilical cord and a microdialysis probe inserted into the right cerebral hemisphere for interstitial fluid sampling. Creatine (6 mg kg−1 h−1) or saline was continuously infused intravenously from 122 dGA. At 131 dGA, a 10 min UCO was induced. Hourly microdialysis samples were obtained from −24 to 72 h post‐UCO and analysed for percentage change of hydroxyl radicals (•OH) and interstitial metabolites (lactate, pyruvate, glutamate, glycerol, glycine). Histochemical markers of protein and lipid oxidation were assessed at post‐mortem 72 h post‐UCO. Prior to UCO, creatine treatment reduced pyruvate and glycerol concentrations in the microdialysate outflow. Creatine treatment reduced interstitial cerebral •OH outflow 0 to 24 h post‐UCO. Fetuses with higher arterial creatine concentrations before UCO presented with reduced levels of hypoxaemia (PO2 and SO2) during UCO which associated with reduced interstitial cerebral pyruvate, lactate and •OH accumulation. No effects of creatine treatment on immunohistochemical markers of oxidative stress were found. In conclusion, fetal creatine treatment decreased cerebral outflow of •OH and was associated with an improvement in cerebral bioenergetics following acute hypoxia. Key points Fetal hypoxia can cause persistent metabolic and oxidative stress responses that disturb energy homeostasis in the brain. Creatine in its phosphorylated form is an endogenous phosphagen; therefore, supplementation is a proposed prophylactic treatment for fetal hypoxia.Fetal sheep instrumented with a cerebral microdialysis probe were continuously infused with or without creatine‐monohydrate for 10 days before induction of 10 min umbilical cord occlusion (UCO; 131 days’ gestation). Cerebral interstitial fluid was collected up to 72 h following UCO.Prior to UCO, fetal creatine supplementation reduced interstitial cerebral pyruvate and glycerol concentrations.Fetal creatine supplementation reduced cerebral hydroxyl radical efflux up to 24 h post‐UCO. Fetuses with higher arterial creatine concentrations before UCO and reduced levels of systemic hypoxaemia during UCO were associated with reduced cerebral interstitial pyruvate, lactate and •OH following UCO.Creatine supplementation leads to some improvements in cerebral bioenergetics following in utero acute hypoxia.

The differential impact of iron on ferroptosis, oxidative stress, and inflammatory reaction in head-kidney macrophages of yellow catfish (Pelteobagrus fulvidraco) with and without ammonia stress

The methylerythritol phosphate (MEP) pathway is responsible for biosynthesis of the precursors of isoprenoid compounds in eubacteria and plastids. It is a metabolic alternative to the well-known mevalonate pathway for isoprenoid production found in archaea and eukaryotes. Recently, a role for the MEP pathway in oxidative stress detection, signalling, and response has been identified. This role is executed in part through the unusual cyclic intermediate, methylerythritol cyclodiphosphate (MEcDP). We postulate that this response is triggered through the oxygen sensitivity of the MEP pathway’s terminal iron-sulfur (Fe-S) cluster enzymes. MEcDP is the substrate of IspG, the first Fe-S cluster enzyme in the pathway; it accumulates under oxidative stress conditions and acts as a signalling molecule. It may also act as an antioxidant. Furthermore, evidence is emerging for a broader and highly nuanced role of the MEP pathway in oxidative stress responses, implemented through a complex system of differential regulation and sensitivity at numerous nodes in the pathway. Here, we explore the evidence for such a role (including the contribution of the Fe-S cluster enzymes and different pathway metabolites, especially MEcDP), the evolutionary implications, and the many questions remaining about the behaviour of the MEP pathway in the presence of oxidative stress.

Background: Traffic-related air pollution is associated with cardiovascular morbidity and mortality. Although the biological mechanisms are not well understood, oxidative stress may be a primary pathway. Subpopulations, such as individuals with metabolic syndrome (MeS), may be at increased risk of adverse effects associated with air pollution. Our aim was to assess the relationship between exposure to diesel exhaust (DE) and indicators of systemic antioxidant and oxidative responses in adults with MeS. We hypothesized that DE exposure would result in greater oxidative stress and antioxidant responses compared with filtered air (FA).Methods: Ten adult subjects with MeS were exposed on separate days for two hours to FA or DE (at 200μg/m3), in a double blind, crossover experiment. Urinary 8-isoPGF2α (F2-isoprostanes), and 8-hydroxy-2’-deoxyguanosine (8-OHdG) were assessed as markers of oxidative stress at 3 hrs and 22 hrs, respectively, after exposure initiation. To assess the short-term antioxidant response we analyzed plasma ascorbic acid (AA) 90 minutes after exposure initiation. All outcomes were compared to pre-exposure levels, and mean changes were compared between FA and DE exposures.Results: Mean changes in urinary F2-isoprostanes (ng/mg creatinine), (−0.05 [95% CI = −0.29, 0.15]), and 8-OHdG (μg/g creatinine) (−0.09 [−0.13, 0.31]), were not statistically significant. Mean changes in plasma AA (mg/dl) were also not significant (−0.02 [−0.78, 0.04]).Conclusions: In this carefully controlled experiment, we did not detect significant changes in oxidative stress or systemic antioxidant responses in subjects with MeS exposed to 200μg/m3 DE.

Fission yeast Spc1 (Sty1), a stress-activated mitogen-activated protein kinase (MAPK) homologous to human p38, orchestrates global changes in gene expression in response to diverse forms of cytotoxic stress. This control is partly mediated through Atf1, a transcription factor homologous to human ATF2. How Spc1 controls Atf1, and how the cells tailor gene expression patterns to different forms of stress, are unknown. Here we describe Csx1, a novel protein crucial for survival of oxidative but not osmotic stress. Csx1 associates with and stabilizes atf1+ mRNA in response to oxidative stress. Csx1 controls expression of the majority of the genes induced by oxidative stress, including most of the genes regulated by Spc1 and Atf1. These studies reveal a novel mechanism controlling MAPK-regulated transcription factors and suggest how gene expression patterns can be customized to specific forms of stress. Csx1-like proteins in humans may perform similar tasks.

Campylobacter jejuni is the leading bacterial cause of foodborne human gastroenteritis worldwide. The first C. jejuni genome (strain NCTC11168) was sequenced in 2000. This original annotation was a milestone in Campylobacter research, but soon became outdated. A re-annotation and re-analysis of this genome sequence was performed resulting in updates to over 90% of coding sequences (CDSs) and modification of 18.2% of CDS product functions (Gundogdu et al., 2007). Following this re-annotation, 15 uncharacterised CDSs with revised functions relating to virulence, signal transduction or regulation of gene expression were selected for further investigation. Defined isogenic C. jejuni 11168H mutants were constructed and after preliminary analysis, the Cj1556 and Cj0248 mutants were selected for further characterisation. Cj1556 was originally annotated as a hypothetical protein and was updated to a MarR family transcriptional regulator. Further bioinformatic analysis indicated a putative role in regulating the oxidative stress response. A C. jejuni 11168H Cj1556 mutant exhibited increased sensitivity to oxidative and aerobic (O2) stress, decreased ability for intracellular survival in both Caco-2 intestinal epithelial cells (IECs) and J774A.1 mouse macrophages and a reduction in virulence in the Galleria mellonella infection model. Microarray analysis of gene expression changes in the Cj1556 mutant compared to the wild-type strain indicated negative autoregulation of Cj1556 expression and down-regulation of genes associated with oxidative and aerobic (O2) stress responses. Cj0248 was originally annotated as a hypothetical protein however the re-annotation identified a HD domain linked to a superfamily of metal-dependent phosphohydrolases with roles in signal transduction in bacteria. Previously a C. jejuni 81-176 Cj0248 mutant was shown to be deficient for motility and chick colonisation, however the exact function of Cj0248 was not investigated. The C. jejuni 11168H Cj0248 mutant also possessed a reduced motility phenotype and exhibited reduced interaction and invasion when co-cultured with Caco-2 IECs compared to the wild-type strain. However the Cj0248 mutant showed no difference in autoagglutination compared to the wild-type strain and TEM analysis indicated the mutant possessed intact flagella. Higher magnification TEM indicated the possibility of an altered flagella basal body region in the Cj0248 mutant. Secretion profile analysis identified no differences in the protein profile of the Cj0248 mutant compared to the wild-type strain. The exact function of Cj0248 remains unclear.

The pathogenic dimorphic fungus Talaromyces marneffei is known to cause a fatal systemic mycosis in immunocompromised patients, especially in HIV patients in Southeast Asia. The basic leucine-zipper (bZip) transcription factor gene, yapA, has been identified in T. marneffei. A prior study described that yapA was involved in the oxidative and nitrosative stress response in T. marneffei. Interestingly, an essential role of Saccharomyces cerevisiae Yap1p in the oxidative stress response is the activation of the transcription of its target genes. To identify the target genes of yapA in T. marneffei, the qRT-PCR method were used in this study. Investigation into the expression of genes which are probably regulated by yapA revealed that yapA controlled the expression of cat1 (catalase), cpeA (catalase-peroxidase), sodA (copper, zinc superoxide dismutase), gcs1 (glutamate-cysteine ligase), glr1 (glutathione oxidoreductase), trr1/trr2 (thioredoxin reductase), and trxA (thioredoxin) during stress conditions in all forms of conidium, mycelium, and yeast phase. An exception to this was the expression of cat1 under conditions of oxidative stress in the mould phase with a similar relative expression level in all of the wild-type, mutant and complemented strains. These genes are involved in response against oxidative stress and nitrosative stress in this fungus. The data showed that they could be regulated by the yapA gene during stress conditions. Moreover, the yapA gene is also known to control red pigment production by inhibiting the regulation of the five polyketide synthase (pks) genes, pks3 (polyketide synthase), rp1 (transcription activator), rp2 (β-subunit fatty acid synthase), rp3 (α-subunit fatty acid synthase), and rp4 (oxidoreductase) in the mould phase. In addition, it also regulates transcription in the laccase gene cluster including lac (extracellular dihydrogeodin oxidase/laccase), and multicopper oxidase encoding genes (PMAA_050860, PMAA_072680, PMAA_085520, PMAA_082010, and PMAA_082060) in all stages of the T. marneffei lifecycle (conidia, mould, and yeast phase). This study suggests the importance of the role of the yapA gene in the stress response and virulence of T. marneffei.

This study presents a comprehensive transcriptome analysis of canine intestinal epithelial cells following treatment with sulforaphane (SFN), a naturally occurring compound found in cruciferous vegetables with established anti-inflammatory and antioxidant properties. Through high-throughput sequencing, we identified 29,993 genes, among which 1,612 were differentially expressed, with 792 up-regulated and 820 down-regulated in response to SFN treatment. Our analysis revealed significant enrichment of genes in pathways associated with the inflammatory response, lipid metabolism, oxidative stress response, and T-cell mediated immunity, suggesting SFN's potential in modulating these biological processes. Notably, the PPARγ gene, which plays a crucial role in the body's oxidative stress and inflammatory response, was highly up-regulated, indicating its possible centrality in SFN's effects. Gene-gene interaction analysis further supported SFN's role in alleviating inflammation through PPARγ, with key genes in oxidative stress and inflammatory response pathways showing significant correlations with PPARγ. Overall, our findings provide molecular evidence for SFN's protective effects on canine intestinal health, potentially through the modulation of inflammatory and oxidative stress pathways, with PPARγ emerging as a critical mediator.

Acute antioxidant supplementation may modulate oxidative stress and some immune perturbations that typically occur following prolonged exercise. The aims of the present study were to examine the effects of acutely consuming dark chocolate (high polyphenol content) on plasma antioxidant capacity, markers of oxidative stress and immunoendocrine responses to prolonged exercise. Fourteen healthy men cycled for 2.5 h at ~60% maximal oxygen uptake 2 h after consuming 100 g dark chocolate (DC), an isomacronutrient control bar (CC) or neither (BL) in a randomised-counterbalanced design. DC enhanced pre-exercise antioxidant status (P = 0.003) and reduced by trend (P = 0.088) 1 h post-exercise plasma free [F₂-isoprostane] compared with CC (also, [F₂-isoprostane] increased post-exercise in CC and BL but not DC trials). Plasma insulin concentration was significantly higher pre-exercise (P = 0.012) and 1 h post-exercise (P = 0.026) in the DC compared with the CC trial. There was a better maintenance of plasma glucose concentration on the DC trial (2-way ANOVA trial × time interaction P = 0.001), which decreased post-exercise in all trials but was significantly higher 1 h post-exercise (P = 0.039) in the DC trial. There were no between trial differences in the temporal responses (trial × time interactions all P > 0.05) of hypothalamic-pituitary-adrenal axis stress hormones, plasma interleukin-6, the magnitude of leukocytosis and neutrophilia and changes in neutrophil function. Acute DC consumption may affect insulin, glucose, antioxidant status and oxidative stress responses, but has minimal effects on immunoendocrine responses, to prolonged exercise.

ABSTRACTStreptococcus mutans promotes a tooth-damaging dysbiosis in the oral microbiota because it can form biofilms and survive acid stress better than most of its ecological competitors, which are typically health associated. Many of these commensals produce hydrogen peroxide; therefore, S. mutans must manage both oxidative stress and acid stress with coordinated and complex physiological responses. In this study, the proteome of S. mutans was examined during regulated growth in acid and oxidative stresses as well as in deletion mutants with impaired oxidative stress phenotypes, Δnox and ΔtreR. A total of 607 proteins exhibited significantly different abundances across the conditions tested, and correlation network analysis identified modules of coexpressed proteins that were responsive to the deletion of nox and/or treR as well as acid and oxidative stress. The data explained the reactive oxygen species (ROS)-sensitive and mutacin-deficient phenotypes exhibited by the ΔtreR strain. SMU.1069-1070, a poorly understood LytTR system, had an elevated abundance in the ΔtreR strain. S. mutans LytTR systems regulate mutacin production and competence, which may explain how TreR affects mutacin production. Furthermore, the protein cluster that produces mutanobactin, a lipopeptide important in ROS tolerance, displayed a reduced abundance in the ΔtreR strain. The role of Nox as a keystone in the oxidative stress response was also emphasized. Crucially, this data set provides oral health researchers with a proteome atlas that will enable a more complete understanding of the S. mutans stress responses that are required for pathogenesis, and will facilitate the development of new and improved therapeutic approaches for dental caries.IMPORTANCE Dental caries is the most common chronic infectious disease worldwide and disproportionately affects marginalized socioeconomic groups. Streptococcus mutans is considered a primary etiological agent of caries, with its pathogenicity being dependent on coordinated physiological stress responses that mitigate the damage caused by the oxidative and acid stress common within dental plaque. In this study, the proteome of S. mutans was examined during growth in acidic and oxidative stresses as well in nox and treR deletion mutants. A total of 607 proteins were differentially expressed across the strains/growth conditions, and modules of coexpressed proteins were identified, which enabled mapping the acid and oxidative stress responses across S. mutans metabolism. The presence of TreR was linked to mutacin production via LytTR system signaling and to oxidative stress via mutanobactin production. The data provided by this study will guide future research elucidating S. mutans pathogenesis and developing improved preventative and treatment modalities for dental caries.

13 - Role of Thioredoxin and Redox Regulation in Oxidative Stress Response and Signaling

The aim of this study was to investigate the effects of butylphthalide on oxidative stress and inflammatory response in rats with myocardial infarction through the protein kinase B/nuclear factor E2-related factor 2 (Akt/Nrf2) signaling pathway. A total of 36 Sprague-Dawley rats were randomly divided into three groups, including sham group (n=12), model group (n=12) and butylphthalide group (n=12). In the sham group, the heart was exposed, and normal saline was intraperitoneally injected after the operation. In the model group, acute myocardial infarction (AMI) model was established, and normal saline was intraperitoneally injected after the operation. In the butylphthalide group, AMI model was established, and butylphthalide was intraperitoneally injected after the operation. After intervention for 4 weeks, the rats were killed, and the samples were collected. The morphology of heart tissues was observed via hematoxylin-eosin (HE) staining. The expression of nicotinamide adenine dinucleotide phosphate oxidase-1 (NOX-1) was detected via immunohistochemistry. The protein expressions of phosphorylated Akt (p-Akt) and p-Nrf2 were detected via Western blotting. Moreover, the content of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) was detected via enzyme-linked immunosorbent assay (ELISA). The messenger ribonucleic acid (mRNA) expression levels of IL-1β, TNF-α and NOX-1 were detected via quantitative Polymerase Chain reaction (qPCR). Furthermore, the apoptosis rate of the cells was detected via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. The morphology of heart tissues was significantly damaged in the model group and butylphthalide group compared with the sham group. However, it was significantly improved in the butylphthalide group when compared with the model group. The expression level of NOX-1 increased markedly in the model group and butylphthalide group compared with the sham group (p<0.05). However, it was remarkably reduced in the butylphthalide group compared with the model group (p<0.05). Meanwhile, the protein expression levels of p-Akt and p-Nrf2 were significantly higher in the model group and butylphthalide group than those of the sham group (p<0.05). However, the protein expression levels of p-Akt and p-Nrf2 in the butylphthalide group were remarkably lower than the model group (p<0.05). The mRNA expression levels of IL-1β, TNF-α and NOX-1 were markedly higher in the model group and butylphthalide group than those of the sham group (p<0.05). However, they remarkably declined in the butylphthalide group compared with the model group (p<0.05). In addition, the content of IL-1β and TNF-α increased in the model group and butylphthalide group when compared with the sham group (p<0.05). The content of IL-1β and TNF-α in the butylphthalide group was significantly lower than the model group (p<0.05). Furthermore, the apoptosis rate was significantly higher in the model group and butylphthalide group than the sham group (p<0.05), which was significantly lower in the butylphthalide group than the model group (p<0.05). Butylphthalide inhibits inflammatory and oxidative stress responses after AMI by regulating the Akt/Nrf2 signaling pathway, thereby inhibiting myocardial apoptosis and benefiting the morphological repair of myocardial tissues.