Enhanced glutathione levels and oxidoresistance mediated by increased glucose-6-phosphate dehydrogenase expression

The Impact of Lifestyle on the Secondary Sex Ratio: A Review

The secondary sex ratio (SSR), indicating the ratio of male to female live births, has garnered considerable attention within the realms of reproductive biology and public health. Numerous factors have been posited as potential trendsetters of the SSR. Given the extensive research on the impact of daily behaviors and habits on individuals' reproductive health, there is a plausible suggestion that lifestyle choices may also influence the SSR. By synthesizing the existing literature on the current research field, this comprehensive review indicates that an elevated SSR has been associated with an increased intake of fatty acids and monosaccharides, proper nutrition, higher educational levels, financial prosperity, and favorable housing conditions. On the other hand, a decreased SSR may be linked to undernutrition, socioeconomic disparities, and psychological distress, aligning with the Trivers-Willard hypothesis. Occupational factors, smoking habits, and cultural beliefs could also contribute to trends in the SSR. Our review underscores the significance of considering the aforementioned factors in studies examining the SSR and emphasizes the necessity for further research to unravel the mechanisms underpinning these connections. A more profound comprehension of SSR alterations due to lifestyle holds the potential to adequately develop public health interventions and healthcare strategies to enhance reproductive health and overall well-being.

Quercetin-loaded nanoemulsions prevent Scopolamine-induced neurotoxicity in male rats

Quercetin (QCT) is well-known as a neuroprotective agent due to its antioxidant capacities and reinstating mitochondrial functions. Scopolamine is commonly used as a model to induce Alzheimer's disease (AD-like) symptoms. The current study develops QCT-loaded nanoemulsion (QCT-NE) accompanied by evaluating its neuro-therapeutic effectiveness against SCO-induced neurotoxicity in male rats. The QCT-NE was prepared by the spontaneous emulsification technique and characterized by using particle size, zeta potential, drug loading, in vitro drug release behavior, and stability studies. In vivo studies were done on adult Wistar rats by applying the Morris water maze (MWM) test to study spatial memory and learning. The levels of lipid peroxidation and reduced glutathione were quantitatively determined to reveal the potential mechanism of SCO-induced oxidative stress. Finally, histological studies were performed using staining techniques. The QCT-NE particle size, zeta potential, polydispersity index (PDI), and DL were obtained at 172.4 ± 16.8 nm, -29 ± 0.26 mV, 0.3 ± 0.07, and 81.42 ± 9.14 %, respectively. The QCT and more effectively QCT-NE reduced the elevation of neurobehavioral abnormalities in the MWM test in SCO-exposed rats. The results of oxidative status showed that SCO significantly could increase the LPO and decrease the GSH levels in the rat's brain. However, QCT-NE treatment was more effective than free QCT to inhibit oxidative damage and was well correlated with histopathological findings. Taken together, QCT-NE, compared to QCT, was superior in ameliorating SCO-induced AD-like symptoms due to its better neuroprotective activity and can be considered a novel supplementary therapeutic agent in AD management.

Stable Isotope-Assisted Untargeted Metabolomics Identifies ALDH1A1-Driven Erythronate Accumulation in Lung Cancer Cells

Using an untargeted stable isotope-assisted metabolomics approach, we identify erythronate as a metabolite that accumulates in several human cancer cell lines. Erythronate has been reported to be a detoxification product derived from off-target glycolytic metabolism. We use chemical inhibitors and genetic silencing to define the pentose phosphate pathway intermediate erythrose 4-phosphate (E4P) as the starting substrate for erythronate production. However, following enzyme assay-coupled protein fractionation and subsequent proteomics analysis, we identify aldehyde dehydrogenase 1A1 (ALDH1A1) as the predominant contributor to erythrose oxidation to erythronate in cell extracts. Through modulating ALDH1A1 expression in cancer cell lines, we provide additional support. We hence describe a possible alternative route to erythronate production involving the dephosphorylation of E4P to form erythrose, followed by its oxidation by ALDH1A1. Finally, we measure increased erythronate concentrations in tumors relative to adjacent normal tissues from lung cancer patients. These findings suggest the accumulation of erythronate to be an example of metabolic reprogramming in cancer cells, raising the possibility that elevated levels of erythronate may serve as a biomarker of certain types of cancer.

Desipramine induces eryptosis in human erythrocytes, an effect blunted by nitric oxide donor sodium nitroprusside and N-acetyl-L-cysteine but enhanced by Calcium depletion

Background: Desipramine a representative of tricyclic antidepressants (TCAs) promotes recovery of depressed patients by inhibition of reuptake of neurotransmitters serotonin (SER) and norepinephrine (NE) in the presynaptic membrane by directly blocking their respective transporters SERT and NET.Aims: To study the effect of desipramine on programmed erythrocyte death (eryptosis) and explore the underlying mechanisms.Methods: Phosphatidylserine (PS) exposure on the cell surface as marker of cell death was estimated from annexin-V-binding, cell volume from forward scatter in flow cytometry. Hemolysis was determined photometrically, and intracellular glutathione [GSH]i from high performance liquid chromatography.Results: Desipramine dose-dependently significantly enhanced the percentage of annexin-V-binding cells and didn´t impact glutathione (GSH) synthesis. Desipramine-induced eryptosis was significantly reversed by pre-treatment of erythrocytes with either nitric oxide (NO) donor sodium nitroprusside (SNP) or N-acetyl-L-cysteine (NAC). The highest inhibitory effect was obtained by using both inhibitors together. Calcium (Ca2+) depletion aggravated desipramine-induced eryptosis. Changing the order of treatment, i.e. desipramine first followed by inhibitors, could not influence the inhibitory effect of SNP or NAC.Conclusion: Antidepressants-caused intoxication can be treated by SNP and NAC, respectively. B) Patients with chronic hypocalcemia should not be treated with tricyclic anti-depressants or their dose should be noticeably reduced.

Brilliant Cresyl Blue Negative Oocytes Show a Reduced Competence for Embryo Development after In Vitro Fertilisation with Sperm Exposed to Oxidative Stress

The extent of oxidative damage transferred by the damaged sperm to the progeny is likely to be limited by the oocyte's repair and antioxidative capacity. We aimed to assess the association between Brilliant Cresyl Blue (BCB) staining in oocytes and their competence for embryo development after in vitro fertilisation (IVF) with damaged sperm. For this purpose, bovine sperm were incubated without (non-oxidised sperm, NOX S) or with 100 µM H2O2 (oxidised sperm, OX S) and were used to fertilise in-vitro-matured bovine oocytes (BCB-pos./BCB-neg.). Unstained oocytes served as controls (US). Development was assessed at 30, 46, 60 h and on Days (D) 7 and 8 after IVF. Total cell number and apoptotic index were analysed in D7 blastocysts. BCB-neg. oocytes showed lower cleavage rates and blastocyst rates than unstained oocytes after IVF with NOX S (p < 0.05). They showed the highest reduction in D7 blastocyst rate upon fertilisation with OX S and showed a delayed embryo development at 46 and 60 h after IVF compared to embryos produced with NOX S (p < 0.05). Total cell number in blastocysts produced with BCB-neg. oocytes was lower (p < 0.05) in the embryos produced with OX S than in embryos after IVF with NOX S. In conclusion, BCB-neg. oocytes have a lower competence to support embryo development after in vitro fertilisation with oxidised sperm.

Natural product preferentially targets redox and metabolic adaptations and aberrantly active STAT3 to inhibit breast tumor growth in vivo

Dysregulated gene expression programs and redox and metabolic adaptations allow cancer cells to survive under high oxidative burden. These mechanisms also represent therapeutic vulnerabilities. Using triple-negative breast cancer (TNBC) as a model, we show that compared to normal human breast epithelial cells, the TNBC cells, MDA-MB-231 and MDA-MB-468 that harbor constitutively active STAT3 also express higher glucose-6-phosphate dehydrogenase (G6PD), thioredoxin reductase (TrxR)1, NADPH, and GSH levels for survival. Present studies discover that the natural product, R001, targets these adaptation mechanisms. Treatment of TNBC cells with R001 inhibited constitutively active STAT3, STAT3-regulated gene expression, and the functions of G6PD and TrxR1. Consequently, in the TNBC, but not normal cells, R001 suppressed GSH levels, but raised NADPH levels, reflective of a loss of mitochondrial respiration and which led to reactive oxygen species (ROS) induction, all of which led to loss of viable cells and inhibition of anchorage-dependent and independent growth. R001 treatment further led to early pyroptosis and late DNA damage, cell cycle arrest, and apoptosis only in the TNBC cells. Oral administration of 5 mg/kg R001 inhibited MDA-MB-468 xenografts growth in mice, with reduced pY705-STAT3, G6PD, TrxR1, and GSH levels. R001 serves as a therapeutic entity that targets the vulnerabilities of TNBC cells to inhibit tumor growth in vivo.

Kinetic and data-driven modeling of pancreatic β-cell central carbon metabolism and insulin secretion

Pancreatic β-cells respond to increased extracellular glucose levels by initiating a metabolic shift. That change in metabolism is part of the process of glucose-stimulated insulin secretion and is of particular interest in the context of diabetes. However, we do not fully understand how the coordinated changes in metabolic pathways and metabolite products influence insulin secretion. In this work, we apply systems biology approaches to develop a detailed kinetic model of the intracellular central carbon metabolic pathways in pancreatic β-cells upon stimulation with high levels of glucose. The model is calibrated to published metabolomics datasets for the INS1 823/13 cell line, accurately capturing the measured metabolite fold-changes. We first employed the calibrated mechanistic model to estimate the stimulated cell's fluxome. We then used the predicted network fluxes in a data-driven approach to build a partial least squares regression model. By developing the combined kinetic and data-driven modeling framework, we gain insights into the link between β-cell metabolism and glucose-stimulated insulin secretion. The combined modeling framework was used to predict the effects of common anti-diabetic pharmacological interventions on metabolite levels, flux through the metabolic network, and insulin secretion. Our simulations reveal targets that can be modulated to enhance insulin secretion. The model is a promising tool to contextualize and extend the usefulness of metabolomics data and to predict dynamics and metabolite levels that are difficult to measure in vitro. In addition, the modeling framework can be applied to identify, explain, and assess novel and clinically-relevant interventions that may be particularly valuable in diabetes treatment.

The Possible Role of Glucose-6-Phosphate Dehydrogenase in the SARS-CoV-2 Infection

Glucose-6-phosphate dehydrogenase (G6PD) is the second rate-limiting enzyme of the pentose phosphate pathway. This enzyme is present in the cytoplasm of all mammalian cells, and its activity is essential for an adequate functioning of the antioxidant system and for the response of innate immunity. It is responsible for the production of nicotinamide adenine dinucleotide phosphate (NADPH), the first redox equivalent, in the pentose phosphate pathway. Viral infections such as SARS-CoV-2 may induce the Warburg effect with an increase in anaerobic glycolysis and production of lactate. This condition ensures the success of viral replication and production of the virion. Therefore, the activity of G6PD may be increased in COVID-19 patients raising the level of the NADPH, which is needed for the enzymatic and non-enzymatic antioxidant systems that counteract the oxidative stress caused by the cytokine storm. G6PD deficiency affects approximately 350–400 million people worldwide; therefore, it is one of the most prevalent diseases related to enzymatic deficiency worldwide. In G6PD-deficient patients exposed to SARS-CoV-2, the amount of NADPH is reduced, increasing the susceptibility for viral infection. There is loss of the redox homeostasis in them, resulting in severe pneumonia and fatal outcomes.

Role of melatonin in promoting plant growth by regulating carbon assimilation and ATP accumulation

Melatonin (MT) is a phytohormone important in mediating diverse plant growth processes. In this study, we performed transcriptomic, qRT-PCR, physiological and biochemical analyses of Brassica rapa seedlings in order to understand how MT promotes plant growth. The results showed that exogenous MT increased the rate of cyclic electron flow around photosystem (PS) I, fluorescence quantum yield, and electron transport efficiency between PSII and PSI to promote the vegetative growth of B. rapa seedlings without affecting oxidative stress level, as compared to control. However, MT treatment significantly reduced photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) by 2.25-, 1.23- and 3.50-fold at 0.05 level, respectively. This occurred in parallel with the down-regulation of the genes for carbon fixation in photosynthetic organisms in a KEGG pathway enrichment. More accelerated plant growth despite the reduced photosynthesis rate and the enhanced electron transport rate suggested that NADPH and adenosine triphosphate (ATP) were preferentially diverted into other anabolic reactions than the Calvin cycle upon MT application. MT treatment increased ATP level and facilitated carbon assimilation into primary metabolism that led to a significant enhancement of soluble protein, sucrose, and fructose, but a significant decrease in glucose content. MT-induced carbon assimilation into primary metabolism was driven by up-regulation of the genes for glutathione metabolism, Krebs cycle, ribosome, and DNA replication in a KEGG pathway enrichment, as well as down-regulation of the genes for secondary metabolites. Our results provide an insight into MT-mediated metabolic adjustments triggered by coordinate changes in a wide range of gene expression profiles to help improve the plant functionality.

Influenza Virus Down-Modulates G6PD Expression and Activity to Induce Oxidative Stress and Promote Its Replication

Influenza virus infection induces oxidative stress in host cells by decreasing the intracellular content of glutathione (GSH) and increasing reactive oxygen species (ROS) level. Glucose-6-phosphate dehydrogenase (G6PD) is responsible for the production of reducing equivalents of nicotinamide adenine dinucleotide phosphate (NADPH) that is used to regenerate the reduced form of GSH, thus restoring redox homeostasis. Cells deficient in G6PD display elevated levels of ROS and an increased susceptibility to viral infection, although the consequences of G6PD modulation during viral infection remain to be elucidated. In this study, we demonstrated that influenza virus infection decreases G6PD expression and activity, resulting in an increase in oxidative stress and virus replication. Moreover, the down regulation of G6PD correlated with a decrease in the expression of nuclear factor erythroid 2-related factor 2 (NRF2), a key transcription factor that regulates the expression of the antioxidant response gene network. Also down-regulated in influenza virus infected cells was sirtuin 2 (SIRT2), a NADPH-dependent deacetylase involved in the regulation of G6PD activity. Acetylation of G6PD increased during influenza virus infection in a manner that was strictly dependent on SIRT2 expression. Furthermore, the use of a pharmacological activator of SIRT2 rescued GSH production and NRF2 expression, leading to decreased influenza virus replication. Overall, these data identify a novel strategy used by influenza virus to induce oxidative stress and to favor its replication in host cells. These observations furthermore suggest that manipulation of metabolic and oxidative stress pathways could define new therapeutic strategies to interfere with influenza virus infection.

Increasing NADPH impairs fungal H2O2 resistance by perturbing transcriptional regulation of peroxiredoxin

NADPH provides the reducing power for decomposition of reactive oxygen species (ROS), making it an indispensable part during ROS defense. It remains uncertain, however, if living cells respond to the ROS challenge with an elevated intracellular NADPH level or a more complex NADPH-mediated manner. Herein, we employed a model fungus Aspergillus nidulans to probe this issue. A conditional expression of glucose-6-phosphate dehydrogenase (G6PD)-strain was constructed to manipulate intracellular NADPH levels. As expected, turning down the cellular NADPH concentration drastically lowered the ROS response of the strain; it was interesting to note that increasing NADPH levels also impaired fungal H2O2 resistance. Further analysis showed that excess NADPH promoted the assembly of the CCAAT-binding factor AnCF, which in turn suppressed NapA, a transcriptional activator of PrxA (the key NADPH-dependent ROS scavenger), leading to low antioxidant ability. In natural cell response to oxidative stress, we noticed that the intracellular NADPH level fluctuated "down then up" in the presence of H2O2. This might be the result of a co-action of the PrxA-dependent NADPH consumption and NADPH-dependent feedback of G6PD. The fluctuation of NADPH is well correlated to the formation of AnCF assembly and expression of NapA, thus modulating the ROS defense. Our research elucidated how A. nidulans precisely controls NADPH levels for ROS defense.

A Novel Sesquiterpene Lactone Xanthatin-13-(pyrrolidine-2-carboxylic acid) Isolated from Burdock Leaf Up-Regulates Cells' Oxidative Stress Defense Pathway

The aim of our study was to identify novel molecules able to induce an adaptative response against oxidative stress during the first stages of metabolic syndrome. A cellular survival in vitro test against H₂O₂-based test was applied after pretreatment with various natural bitter Asteraceae extracts. This screening revealed potent protection from burdock leaf extract. Using chromatography and LC-MS—RMN, we then isolated and identified an original sesquiterpene lactone bioactive molecule: the Xanthatin-13-(pyrrolidine-2-carboxylic acid) (XPc). A real-time RT-qPCR experiment was carried out on three essential genes involved in oxidative stress protection: GPx, SOD, and G6PD. In presence of XPc, an over-expression of the G6PD gene was recorded, whereas no modification of the two others genes could be observed. A biochemical docking approach demonstrated that XPc had a high probability to directly interact with G6PD at different positions. One of the most probable docking sites corresponds precisely to the binding site of AG1, known to stabilize the G6PD dimeric form and enhance its activity. In conclusion, this novel sesquiterpene lactone XPc might be a promising prophylactic bioactive agent against oxidative stress and inflammation in chronic diseases such as metabolic syndrome or type 2 diabetes.

Seven novel glucose-6-phosphate dehydrogenase (G6PD) deficiency variants identified in the Qatari population

Background

Glucose-6-phosphate dehydrogenase deficiency (G6PDD) is the most common red cell enzymopathy in the world. In Qatar, the incidence of G6PDD is estimated at around 5%; however, no study has investigated the genetic basis of G6PDD in the Qatari population yet.

Methods

In this study, we analyzed whole-genome sequencing data generated by the Qatar Genome Programme for 6045 Qatar Biobank participants, to identify G6PDD variants in the Qatari population. In addition, we assessed the impact of the novel variants identified on protein function both in silico and by measuring G6PD enzymatic activity in the subjects carrying them.

Results

We identified 375 variants in/near G6PD gene, of which 20 were high-impact and 16 were moderate-impact variants. Of these, 14 were known G6PDD-causing variants. The most frequent G6PD-causing variants found in the Qatari population were p.Ser188Phe (G6PD Mediterranean), p.Asn126Asp (G6PD A +), p.Val68Met (G6PD Asahi), p.Ala335Thr (G6PD Chatham), and p.Ile48Thr (G6PD Aures) with allele frequencies of 0.0563, 0.0194, 0.00785, 0.0050, and 0.00380, respectively. Furthermore, we have identified seven novel G6PD variants, all of which were confirmed as G6PD-causing variants and classified as class III variants based on the World Health Organization’s classification scheme.

Conclusions

This is the first study investigating the molecular basis of G6PDD in Qatar, and it provides novel insights about G6PDD pathogenesis and highlights the importance of studying such understudied population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40246-021-00358-9.

Metallothioneins in Inflammatory Bowel Diseases: Importance in Pathogenesis and Potential Therapy Target

Immunological disorders, increased oxidative stress, and damage to the epithelial barrier play an important role in the pathogenesis of inflammatory bowel diseases (IBDs). In the treatment of patients with Crohn's disease (CD) and ulcerative colitis (UC), it is increasingly common to use biological drugs that selectively affect individual components of the inflammatory cascade. However, administering the medicines currently available does not always result in obtaining and maintaining remission, and it may also lead to the development of resistance to a given agent over time. Metallothioneins (MTs) belong to the group of low molecular weight proteins, which, among others, regulate the inflammation and homeostasis of heavy metals as well as participating in the regulation of the intensity of oxidative stress. The results of the studies conducted so far do not clearly indicate the role of MTs in the process of inflammation in patients with IBD. However, there are reports that suggest the possibility of using MTs as a potential target in the treatment of this group of patients.

8-Week Supplementation of 2S-Hesperidin Modulates Antioxidant and Inflammatory Status after Exercise until Exhaustion in Amateur Cyclists

Both acute and chronic ingestion of 2S-hesperidin have shown antioxidant and anti-inflammatory effects in animal studies, but so far, no one has studied this effect of chronic ingestion in humans. The main objective was to evaluate whether an 8-week intake of 2S-hesperidin had the ability to modulate antioxidant-oxidant and inflammatory status in amateur cyclists. A parallel, randomized, double-blind, placebo-controlled trial study was carried out with two groups (500 mg/d 2S-hesperidin; n = 20 and 500 mg/d placebo; n = 20). An incremental test was performed to determine the working zones in a rectangular test, which was used to analyze for changes in antioxidant and inflammatory biomarkers. After 2S-hesperidin ingestion, we found in the rectangular test: (1) an increase in superoxide dismutase (SOD) after the exercise phase until exhaustion (p = 0.045) and the acute recovery phase (p = 0.004), (2) a decrease in the area under the oxidized glutathione curve (GSSG) (p = 0.016), and (3) a decrease in monocyte chemoattractant protein 1 (MCP1) after the acute recovery phase (p = 0.004), post-intervention. Chronic 2S-hesperidin supplementation increased endogenous antioxidant capacity (↑SOD) after maximal effort and decreased oxidative stress (↓AUC-GSSG) during the rectangular test, decreasing inflammation (↓MCP1) after the acute recovery phase.

Fasting ameliorates oxidative stress: A review of physiological strategies across life history events in wild vertebrates

Fasting is a component of many species' life history due to environmental factors or behavioral patterns that limit access to food. Despite metabolic and physiological challenges associated with these life history stages, fasting-adapted wild vertebrates exhibit few if any signs of oxidative stress, suggesting that fasting promotes redox homeostasis. Here we review mammalian, avian, reptilian, amphibian, and piscine examples of animals undergoing fasting during prolonged metabolic suppression (e.g. hibernation and estivation) or energetically demanding processes (e.g. migration and breeding) to better understand the mechanisms underlying fasting tolerance in wild vertebrates. These studies largely show beneficial effects of fasting on redox balance via limited oxidative damage. Though some species exhibit signs of oxidative stress due to energetically or metabolically extreme processes, fasting wild vertebrates largely buffer themselves from the negative consequences of oxidative damage through specific strategies such as elevating antioxidants, selectively maintaining redox balance in critical tissues, or modifying behavioral patterns. We conclude with suggestions for future research to better elucidate the protective effects of fasting on oxidative stress as well as disentangle the impacts from other life history stages. Further research in these areas will facilitate our understanding of the mechanisms wild vertebrates use to mitigate the negative impacts associated with metabolically-extreme life history stages as well as potential translation into therapeutic interventions in non-fasting-adapted species including humans.

G6PD overexpression protects from oxidative stress and age-related hearing loss

Aging of the auditory system is associated with the incremental production of reactive oxygen species (ROS) and the accumulation of oxidative damage in macromolecules, which contributes to cellular malfunction, compromises cell viability, and, ultimately, leads to functional decline. Cellular detoxification relies in part on the production of NADPH, which is an important cofactor for major cellular antioxidant systems. NADPH is produced principally by the housekeeping enzyme glucose‐6‐phosphate dehydrogenase (G6PD), which catalyzes the rate‐limiting step in the pentose phosphate pathway. We show here that G6PD transgenic mice (G6PD‐Tg), which show enhanced constitutive G6PD activity and NADPH production along life, have lower auditory thresholds than wild‐type mice during aging, together with preserved inner hair cell (IHC) and outer hair cell (OHC), OHC innervation, and a conserved number of synapses per IHC. Gene expression of antioxidant enzymes was higher in 3‐month‐old G6PD‐Tg mice than in wild‐type counterparts, whereas the levels of pro‐apoptotic proteins were lower. Consequently, nitration of proteins, mitochondrial damage, and TUNEL⁺ apoptotic cells were all lower in 9‐month‐old G6PD‐Tg than in wild‐type counterparts. Unexpectedly, G6PD overexpression triggered low‐grade inflammation that was effectively resolved in young mice, as shown by the absence of cochlear cellular damage and macrophage infiltration. Our results lead us to propose that NADPH overproduction from an early stage is an efficient mechanism to maintain the balance between the production of ROS and cellular detoxification power along aging and thus prevents hearing loss progression.

Glutathione-redox status on hydro alcoholic root bark extract of Premna integrifolia Linn in high fat diet induced atherosclerosis model

BACKGROUND

Premna integrifolia Linn. is a medicinal plant of an Ayurvedic importance and proved to have an anti-inflammatory, anti-diabetic, anti-microbial and hypo-lipidemic activity. Glutathione (GSH) redox status is an important parameter to assess the antioxidant activity of any neutraceuticals.

OBJECTIVE

In order to assess the anti-oxidant potential of hydro alcoholic extract (HAE) of P. integrifolia, this study was aimed to evaluate the GSH redox status in high fat diet induced experimental atherosclerosis.

MATERIALS AND METHODS

The present study comprises sixty Wistar rats and they were divided into six groups: the first group served as control, the second group was fed with high fat diet and the third, fourth and fifth groups were fed with high fat diet along with various concentrations of HAE of 200, 400 and 500 g/kg.b.wt respectively and the sixth group was administered high fat diet along with 10 mg/kg b.wt of atorvastatin for 30 days. GSH-dependent enzymes like GSH-peroxidase (GPx), GSH-reductase (GR) and glucose 6-phosphate dehydrogenase (G6PD) were estimated in hemolysate, kidney, heart and liver of experimental rats.

RESULTS

Analysis of GSH levels showed a significant decrease in hemolysate, heart and kidney (p < 0.05) and liver (p < 0.01) in high fat-fed rats when compared to control. Activities of GPx, GR and G6PD in hemolysate and heart (p < 0.001), liver and kidney (p < 0.05) in high fat-fed rats when compared to control. Dose-dependent increase was observed in rats treated with various concentrations of HAE.

CONCLUSION

The HAE of root bark of P. integrifolia is proved to have a protective role on antioxidant defense in high fat diet induced atherosclerosis model. As a whole P. integrifolia increases the GSH content in a dose-dependent manner and in turn altered the redox cycle.

An association between mitochondria and microglia effector function. What do we think we know?

While resident innate immune cells of the central nervous system, the microglia, represent a cell population unique in origin, microenvironment, and longevity, they assume many properties displayed by peripheral macrophages. One prominent shared property is the ability to undergo a metabolic switch towards glycolysis and away from oxidative phosphorylation (OXPHOS) upon activation by the pro-inflammatory stimuli lipopolysaccharide. This shift serves to meet specific cellular demands and allows for cell survival, similar to the Warburg effect demonstrated in cancer cells. In contrast, normal survelliance phenotype or stimulation to a non-proinflammatory phenotype relies primarily on OXPHOS and fatty acid oxidation. Thus, mitochondria appear to function as a pivotal signaling platform linking energy metabolism and macrophage polarization upon activation. These unique shifts in cell bioenergetics in response to different stimuli are essential for proper effector responses at sites of infection, inflammation, or injury. Here we present a summary of recent developments as to how these dynamics characterized in peripheral macrophages are displayed in microglia. The new insights provided by an increased understanding of metabolic reprogramming in macrophages may allow for translation to the CNS and a better understanding of microglia heterogeneity, regulation, and function.

Glucose-6-Phosphate Dehydrogenase from the Oleaginous Microalga Nannochloropsis Uncovers Its Potential Role in Promoting Lipogenesis

Microalgae have long been considered as potential biological feedstock for the production of wide array of bioproducts, such as biofuel feedstock because of their lipid accumulating capability. However, lipid productivity of microalgae is still far below commercial viability. Here, a glucose-6-phosphate dehydrogenase from the oleaginous microalga Nannochloropsis oceanica is identified and heterologously expressed in the green microalga Chlorella pyrenoidosa to characterize its function in the pentose phosphate pathway. It is found that the G6PD enzyme activity toward NADPH production is increased by 2.19-fold in engineered microalgal strains. Lipidomic analysis reveals up to 3.09-fold increase of neutral lipid content in the engineered strains, and lipid yield is gradually increased throughout the cultivation phase and saturated at the stationary phase. Moreover, cellular physiological characteristics including photosynthesis and growth rate are not impaired. Collectively, these results reveal the pivotal role of glucose-6-phosphate dehydrogenase from N. oceanica in NADPH supply, demonstrating that provision of reducing power is crucial for microalgal lipogenesis and can be a potential target for metabolic engineering.

Proteomic analysis of Paracoccidioides brasiliensis complex isolates: Correlation of the levels of differentially expressed proteins with in vivo virulence

BACKGROUND

Paracoccidioidomycosis (PCM) is a systemic mycosis commonly found in Latin America that is caused by distinct species of Paracoccidioides genus: Paracoccidioides brasiliensis complex (S1, PS2, PS3 and PS4) and Paracoccidioides lutzii. Its pathobiology has been recently explored by different approaches to clarify the mechanisms of host-pathogen interactions underpinning PCM. The diversity of clinical forms of this disease has been attributed to both host- and fungus-related factors.

METHODOLOGY/PRINCIPAL FINDINGS

For better understanding of the molecular underpinnings of host-fungus interactions, we evaluated in vivo virulence of nine Paracoccidioides brasiliensis complex isolates and correlated it to protein expression profiles obtained by two-dimensional gel electrophoresis. Based on the recovery of viable fungi from mouse organs, the isolates were classified as those having low, moderate, or high virulence. Highly virulent isolates overexpressed proteins related to adhesion process and stress response, probably indicating important roles of those fungal proteins in regulating the colonization capacity, survival, and ability to escape host immune system reaction. Moreover, highly virulent isolates exhibited enhanced expression of glycolytic pathway enzymes concomitantly with repressed expression of succinyl-CoA ligase beta chain, a protein related to the tricarboxylic acid cycle.

CONCLUSIONS/SIGNIFICANCE

Our findings may point to the mechanisms used by highly virulent P. brasiliensis isolates to withstand host immune reactions and to adapt to transient iron availability as strategies to survive and overcome stress conditions inside the host.

Evidence of Hypoxic Glial Cells in a Model of Ocular Hypertension

Purpose

Reoxygenation after hypoxia can increase reactive oxygen species and upregulate autophagy. We determined, for the first time, the impact of elevated IOP on hypoxia induction, superoxide accumulation, and autophagy in a bead model of glaucoma.

Method

Ocular hypertension was achieved with magnetic bead injection into the anterior chamber. Before mice were killed, they were injected with pimonidazole for hypoxia detection and dihydroethidium (DHE) for superoxide detection. Total retinal ganglion cells (RGCs) and optic nerve (ON) axons were quantified, total glutathione (GSH) was measured, and retinal and ON protein and mRNA were analyzed for hypoxia (Hif-1α and Hif-2α), autophagy (LC3 and p62), and SOD2.

Results

With IOP elevation (P < 0.0001), the retina showed significantly (P < 0.001) decreased GSH compared with control, and a significant decrease (P < 0.01) in RGC density compared with control. Pimonidazole-positive Müller glia, microglia, astrocytes, and RGCs were present in the retinas after 4 weeks of ocular hypertension but absent in both the control and after only 2 weeks of ocular hypertension. The ON showed significant axon degeneration (P < 0.0001). The mean intensity of DHE in the ganglion cell layer and ON significantly increased (P < 0.0001). The ratio of LC3-II to LC3-I revealed a significant increase (P < 0.05) in autophagic activity in hypertensive retinas compared with control.

Conclusions

We report a novel observation of hypoxia and a significant decrease in GSH, likely contributing to superoxide accumulation, in the retinas of ocular hypertensive mice. The significant increase in the ratio of LC3-II to LC3-I suggests autophagy induction.

Glutathione "Redox Homeostasis" and Its Relation to Cardiovascular Disease

More people die from cardiovascular diseases (CVD) than from any other cause. Cardiovascular complications are thought to arise from enhanced levels of free radicals causing impaired "redox homeostasis," which represents the interplay between oxidative stress (OS) and reductive stress (RS). In this review, we compile several experimental research findings that show sustained shifts towards OS will alter the homeostatic redox mechanism to cause cardiovascular complications, as well as findings that show a prolonged antioxidant state or RS can similarly lead to such cardiovascular complications. This experimental evidence is specifically focused on the role of glutathione, the most abundant antioxidant in the heart, in a redox homeostatic mechanism that has been shifted towards OS or RS. This may lead to impairment of cellular signaling mechanisms and elevated pools of proteotoxicity associated with cardiac dysfunction.

Heat shock protein B1 is a key mediator of prolactin-induced beta-cell cytoprotection against oxidative stress

Maintaining islet cell viability in vitro, although challenging, appears to be a strategy for improving the outcome of pancreatic islet transplantation. We have shown that prolactin (PRL) leads to beta-cell cytoprotection against apoptosis, an effect mediated by heat shock protein B1 (HSPB1). Since the role of HSPB1 in beta-cells is still unclear and the hormone concentration used is not compatible with clinical applications because of all the side effects displayed by the hormone in other tissues, we explored the molecular mechanisms by which HSPB1 mediates beta-cell cytoprotection. Lysates from PRL- and/or cytokine-treated MIN6 beta-cells were subjected to HSPB1 immunoprecipitation followed by identification through mass spectrometry. PRL-treated cells presented an enrichment of several proteins co-precipitating with HSPB1. Of note were oxidative stress resistance-, protein degradation- and carbohydrate metabolism-related proteins. Wild type, HSPB1 silenced or overexpressing MIN6 cells were exposed to menadione and hydrogen peroxide and analysed for several oxidative stress parameters. HSPB1 knockdown rendered cells more sensitive to oxidative stress and led to a reduced antioxidant capacity, while prolactin induced an HSPB1-mediated cytoprotection against oxidative stress. HSPB1 overexpression, however, led to opposite effects. PRL treatment, HSPB1 silencing or overexpression did not change the expression nor activities of antioxidant enzymes, it also did not lead to a modulation of total glutathione levels nor G6PD expression. However, HSPB1 levels are related to a modulation of GSH/GSSG ratio, G6PD activity and NADPH/NADP ⁺ ratio. We have shown that HSPB1 is important for pro-survival effects against oxidative stress-induced beta-cell death. These results are in accordance with PRL-induced enrichment of HSPB1-interacting proteins related to protection against oxidative stress. Finally, our results outline the need of further studies investigating the importance of HSPB1 for beta-cell viability, since this could lead to the mitigation of beta-cell death through the up-regulation of an endogenous protective pathway.

Comparison of the effects of sulforaphane and pioglitazone on insulin resistance and associated dyslipidemia, hepatosteatosis, and endothelial dysfunction in fructose-fed rats

The purpose of this work was to compare the influences of sulforaphane (SFN) to those of the standard insulin sensitizer pioglitazone (PIO) on high fructose diet (HFrD)-induced insulin resistance, dyslipidemia, hepatosteatosis, and vascular dysfunction in rats. Male Sprague Dawley rats (150-200 g) were fed on a standard diet (control) or a high fructose diet (HFrD, 60% w/w fructose) for 60 days. From day 16, two subgroups of HFrD-fed rats received either SFN (0.5 mg/kg/day, orally) or PIO (5 mg/kg/day, orally) along with HFrD until the end of the experiment. Fructose-fed rats showed significant decreases in food intake, body weight and feeding efficiency; effects that were not altered by either treatment. Data from insulin tolerance test (ITT), oral glucose tolerance test (OGTT), and HOMA-IR and HOMA-β indices demonstrated impaired insulin sensitivity and glucose utilization in HFrD-fed rats. SFN and PIO treatments significantly reduced OGTT_AUC (Glass's Delta values = 1.12 and 0.84, respectively), decreased ITT_AUC (Glass's Delta values = 1.05 and 0.71, respectively), significantly diminished HOMA-IR index (by 55.6% and 77.6%, respectively), and increased HOMA-β value (by 1.8 and 1.3 fold, respectively) compared to the HFrD rats. Moreover, SFN and PIO ameliorated hepatic oxidative stress and reduced serum levels of C-reactive protein and lactate dehydrogenase in HFrD-fed rats. Furthermore, SFN and PIO administrations improved insulin resistance-associated heaptosteatosis and enhanced vascular responsiveness to acetylcholine-induced relaxations. However, only SFN was able to enhance serum HDL-C levels in HFrD group. These finding suggests that SFN elicited insulin-sensitizing, hepatoprotective, and vasculoprotective effects in HFrD insulin-resistant rats that were comparable to those exerted by PIO.

Metabolomics analysis of 'Housui' Japanese pear flower buds during endodormancy reveals metabolic suppression by thermal fluctuation

Dormancy is a complex phenomenon that allows plants to survive the winter season. Studies of dormancy have recently attracted more attention due to the expansion of temperate fruit production in areas under mild winters and due to climate changes. This study aimed to identify and characterize the metabolic changes induced by chilling temperatures, as well as during thermal fluctuation conditions that simulate mild winter and/or climate change scenarios. To do this, we compared the metabolic profile of Japanese pear flower buds exposed to constant chilling at 6 °C and thermal fluctuations of 6 °C/18 °C (150 h/150 h) during endodormancy. We detected 91 metabolites by gas chromatography paired with time-of-flight mass spectrometry (GC-TOF-MS) that could be classified into eight groups: amino acids, amino acid derivatives, organic acids, sugars and polyols, fatty acids and sterols, phenol lipids, phenylpropanoids, and other compounds. Metabolomics analysis revealed that the level of several amino acids decreased during endodormancy. Sugar and polyol levels increased during endodormancy during constant chilling and might be associated with chilling stress tolerance and providing an energy supply for resuming growth. In contrast, thermal fluctuations produced low levels of metabolites related to the pentose phosphate pathway, energy production, and tricarboxylic acid (TCA) cycle in flower buds, which may be associated with failed endodormancy release. This metabolic profile contributes to our understanding of the biological mechanism of dormancy during chilling accumulation and clarifies the metabolic changes during mild winters and future climate change scenarios.

Wild-type and mutated IDH1/2 enzymes and therapy responses

Isocitrate dehydrogenase 1 and 2 (IDH1/2) are key enzymes in cellular metabolism, epigenetic regulation, redox states, and DNA repair. IDH1/2 mutations are causal in the development and/or progression of various types of cancer due to supraphysiological production of d-2-hydroxyglutarate. In various tumor types, IDH1/2-mutated cancers predict for improved responses to treatment with irradiation or chemotherapy. The present review discusses the molecular basis of the sensitivity of IDH1/2-mutated cancers with respect to the function of mutated IDH1/2 in cellular processes and their interactions with novel IDH1/2-mutant inhibitors. Finally, lessons learned from IDH1/2 mutations for future clinical applications in IDH1/2 wild-type cancers are discussed.

Glucose-6-phosphate dehydrogenase inhibition attenuates acute lung injury through reduction in NADPH oxidase-derived reactive oxygen species

Acute lung injury (ALI) is a heterogeneous disease with the hallmarks of alveolar capillary membrane injury, increased pulmonary oedema and pulmonary inflammation. The most common direct aetiological factor for ALI is usually parenchymal lung infection or haemorrhage. Reactive oxygen species (ROS) generated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX2) are thought to play an important role in the pathophysiology of ALI. Glucose-6-phosphate dehydrogenase (G6PD) plays an important role both in production of ROS as well as their removal through the supply of NADPH. However, how G6PD modulation affects NOX2-mediated ROS in the airway epithelial cells (AECs) during acute lung injury has not been explored previously. Therefore, we investigated the effect of G6PD inhibitor, 6-aminonicotinamide on G6PD activity, NOX2 expression, ROS production and enzymatic anti-oxidants in AECs in a mouse model of ALI induced by lipopolysaccharide (LPS). ALI led to increased G6PD activity in the AECs with concomitant elevation of NOX2, ROS, SOD1 and nitrotyrosine. G6PD inhibitor led to reduction of LPS-induced airway inflammation, bronchoalveolar lavage fluid protein concentration as well as NOX2-derived ROS and subsequent oxidative stress. Conversely, ALI led to decreased glutathione reductase activity in AECs, which was normalized by G6PD inhibitor. These data show that activation of G6PD is associated with enhancement of oxidative inflammation in during ALI. Therefore, inhibition of G6PD might be a beneficial strategy during ALI to limit oxidative damage and ameliorate airway inflammation.

Control of the NADPH supply for oxidative stress handling in cancer cells

It has not been systematically analyzed whether the NADPH supply is a limiting factor for oxidative stress management in cancer cells. In the present work, it was determined in non-cancer and cancer cells the protein contents and kinetomics of (i) the cytosolic enzymes responsible for the NADPH production (i.e., Glc6PDH, 6PGDH, ME, IDH-1); and (ii) the two main enzymes responsible for NADPH/NADP⁺ and GSH/GSSG recycling (GR, GPx-1) associated to oxidative stress management. With these data, kinetic models were built and further validated. Rat liver and hepatoma AS-30D cytosolic fractions exhibited greater Vmax for IDH-1 than for Glc6PDH and 6PGDH whereas human cancer cells and platelets showed greater Vmax for Glc6PDH than for 6PGDH and IDH-1. The ME activity was comparatively low in all cell types tested. The Km values for the respective specific substrates were all similar among the different cell types. Most activities were lower in AS-30D cells than in liver. In contrast, IDH-1, Glc6PDH and GR activities in human cancer cells were similar or greater to those of platelets, but GPx-1 activity was severely suppressed, despite showing similar GPx-1 protein content vs. platelets. Kinetic analysis and pathway modeling revealed a previously unveiled feedback IDH-1 regulation by GSH. The oxidative stress management in cancer cells (i) was mainly controlled by GPx-1 and the main NADPH provider was Glc6PDH; and (ii) modeling indicated that NADPH supply was not a controlling step. These data suggested that Glc6PDH and GPx-1 are adequate and promising targets for anti-cancer therapeutic intervention.

Strain differences in arsenic-induced oxidative lesion via arsenic biomethylation between C57BL/6J and 129X1/SvJ mice

Arsenic is a common environmental and occupational toxicant with dramatic species differences in its susceptibility and metabolism. Mouse strain variability may provide a better understanding of the arsenic pathological profile but is largely unknown. Here we investigated oxidative lesion induced by acute arsenic exposure in the two frequently used mouse strains C57BL/6J and 129X1/SvJ in classical gene targeting technique. A dose of 5 mg/kg body weight arsenic led to a significant alteration of blood glutathione towards oxidized redox potential and increased hepatic malondialdehyde content in C57BL/6J mice, but not in 129X1/SvJ mice. Hepatic antioxidant enzymes were induced by arsenic in transcription in both strains and many were higher in C57BL/6J than 129X1/SvJ mice. Arsenic profiles in the liver, blood and urine and transcription of genes encoding enzymes involved in arsenic biomethylation all indicate a higher arsenic methylation capacity, which contributes to a faster hepatic arsenic excretion, in 129X1/SvJ mice than C57BL/6J mice. Taken together, C57BL/6J mice are more susceptible to oxidative hepatic injury compared with 129X1/SvJ mice after acute arsenic exposure, which is closely associated with arsenic methylation pattern of the two strains.

Aged garlic extract ameliorates immunotoxicity, hematotoxicity and impaired burn-healing in malathion- and carbaryl-treated male albino rats

Malathion and carbaryl are the most widely used organophosphate and carbamate insecticides, respectively, especially in developing countries; they pose a potential health hazard for both humans and animals. Here, we evaluated the protective effects of an odorless (free from allicin) Kyolic aged garlic extract (AGE, containing 0.1% S-allylcysteine; 200 mg/kg body weight) on the toxicity induced by 0.1 LD₅₀ of malathion (89.5 mg/kg body weight) and/or carbaryl (33.9 mg/kg body weight) in male Wistar rats. Doses were orally administered to animals for four consecutive weeks. The present study showed that AGE completely modulated most adverse effects induced by malathion and/or carbaryl in rats including the normocytic normochromic anemia, immunosuppression, and the delay in the skin-burning healing process through normalizing the count of blood cells (erythrocytes, leucocytes and platelets), hemoglobin content, hematocrit value, blood glucose-6-phosphodehydrogenase activity, weights and cellularity of lymphoid organs, serum γ-globulin concentration, and the delayed type of hypersensitivity response to the control values, and accelerating the inflammatory and proliferative phases of burn-healing. In addition, AGE completely modulated the decrease in serum reduced glutathione (GSH) concentration and the increase in clotting time in malathion alone and carbaryl alone treated rats. Moreover, AGE induced a significant increase (P < 0.001) in serum GSH concentration (above the normal value) and accelerating burn-healing process in healthy rats. In conclusion, AGE was effective in modulating most adverse effects induced in rats by malathion and carbaryl, and hence may be useful as a dietary adjunct for alleviating the toxicity in highly vulnerable people to insecticides intoxication. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 789-798, 2017.

Biochemical and histological biomarkers in the midgut of Apis mellifera from polluted environment at Beheira Governorate, Egypt

The aim of this study was to analyze the impact of organophosphorus (OP) pollutants on oxidative stress and ultrastructural biomarkers in the midgut of the honeybee Apis mellifera collected from three locations that differ in their extent of spraying load with OP insecticides: a weakly anthropised rural site, Bolin which is considered as a reference site; moderately spraying site, El Kaza; and a strongly anthropised urban site, Tiba with a long history of pesticide use. Results showed that high concentrations of chlorpyrifos, malathion, diazinon, chlorpyrifos-methyl, and pirimiphos-methyl were detected in midgut at locations with extensive pesticide spraying. Reduced glutathione content, superoxide dismutase, catalase, and glutathione peroxidase displayed lowest activities in the heavily sprayed location (Tiba). Lipid peroxidation level in the midgut of honeybees in the sprayed locations was found to be significantly higher compared to the reference values. Meanwhile, various ultrastructural abnormalities were observed in the epithelial cells of midgut of honeybees collected from El Kaza and Tiba, included confluent and disorganized microvilli and destruction of their brush border, the cytoplasm with large vacuoles and alteration of cytoplasmic organelles including the presence of swollen mitochondria with lysis of matrices, disruption of limiting membranes, and disintegration of cristae. The nuclei with indented nuclear envelope and disorganized chromatin were observed. These investigated biomarkers indicated that the surveyed honeybees are being under stressful environmental conditions. So, we suggest using those biomarkers in the assessment of environmental quality using honeybees in future monitoring of ecotoxicological studies.

Antimetabolite TTL-315 selectively kills glucose-deprived cancer cells and enhances responses to cytotoxic chemotherapy in preclinical models of cancer

Maintaining thiol homeostasis is an imperative for cancer cell survival in the nutrient-deprived microenvironment of solid tumors. Despite this metabolic vulnerability, a selective approach has yet to be developed to disrupt thiol homeostasis in solid tumors for therapeutic purposes. In this study, we report the identification of 2-mercaptopropionyl glycine disulfide (TTL-315) as a novel antimetabolite that blocks cell survival in a manner conditional on glucose deprivation. In the presence of glucose, TTL-315 lacks cytotoxic effects in normal cells where it is detoxified by reduction to 2-mercaptopropionyl glycine, a compound with known clinical pharmacologic and safety profiles. In several rodent models of aggressive breast, lung and skin cancers, TTL-315 blocked tumor growth and cooperated with the DNA damaging drug cisplatin to trigger tumor regression. Our results offer preclinical proof of concept for TTL-315 as a novel antimetabolite to help selectively eradicate solid tumors by exploiting the glucose-deprived conditions of the tumor microenvironment.

Oxidative Stress Plays an Important Role in the Pathogenesis of Drug-Induced Retinopathy

Several pharmaceutical agents have been associated with rare but serious retinopathies, some resulting in blindness. Little is known of the mechanism(s) that produce these injuries. Mechanisms proposed thus far have not been embraced by the medical and scientific communities. However, preclinical and clinical data indicate that oxidative stress may contribute substantially to iatrogenic retinal disease. Retinal oxidative stress may be precipitated by the interaction of putative retinal toxins with the ocular redox system. The retina, replete with cytochromes P450 and myeloperoxidase, may serve to activate xenobiotics to oxidants, resulting in ocular injury. These activated agents may directly form retinal adducts or may diminish ocular reduced glutathione concentrations. Data are reviewed that suggest that indomethacin, tamoxifen, thioridazine, and chloroquine all produce retinopathies via a common mechanism—they produce ocular oxidative stress.

Dietary carbohydrates improve oxidative status of common dentex (Dentex dentex) juveniles, a carnivorous fish species

Common dentex (Dentex dentex) is an appreciated carnivorous fish with high growth rate and life cycle adaptable to existing farming techniques. Since the use of carbohydrates is an economic and sustainable alternative for a protein-sparing effect, the study of how this macronutrient affects the welfare of carnivorous species must be studied. The aim of the present study was to evaluate the effects of different types and levels of carbohydrates on common dentex oxidative status. Nine isonitrogenous (43%) and isoenergetic (22MJkg^-1) diets were formulated combining three types (pregelatinized starch-PS, dextrin-Dx and maltodextrin-Mx) and three levels (12, 18 and 24%) of carbohydrates. The activities of catalase-CAT, superoxide dismutase-SOD, glutathione peroxidase-GPX, glutathione reductase-GR and glucose 6-phosphate dehydrogenase-G6PDH, SOD isoenzymatic profile, lipid peroxidation-LPO and protein oxidation-PO were determined in liver and white muscle. SOD and CAT were not affected. GPX in liver and white muscle and GR in liver increased at higher inclusion carbohydrates levels. The lowest levels of GR and G6PDH in both tissues and LPO in liver were observed in maltodextrin groups. No significant effects by carbohydrate source were observed in liver PO and white muscle LPO. Regarding carbohydrate level effect, 18% and 24% dietary inclusion level decreased LPO in white muscle and PO in liver. LPO in liver was also decreased at 24% inclusion level. Altogether, results indicate the use of carbohydrates as an alternative energy source does not produce negative effects on oxidative status of common dentex, on the contrary, even contribute to their oxidative protection.

Elevation of Glucose 6-Phosphate Dehydrogenase Activity Induced by Amplified Insulin Response in Low Glutathione Levels in Rat Liver

Weanling male Wistar rats were fed on a 10% soybean protein isolate (SPI) diet for 3 weeks with or without supplementing 0.3% sulfur-containing amino acids (SAA; methionine or cystine) to examine relationship between glutathione (GSH) levels and activities of NADPH-producing enzymes, glucose 6-phosphate dehydrogenase (G6PD) and malic enzyme (ME), in the liver. Of rats on the 10% SPI diet, GSH levels were lower and the enzyme activities were higher than of those fed on an SAA-supplemented diet. Despite the lower GSH level, γ-glutamylcysteine synthetase (γ-GCS) activity was higher in the 10% SPI group than other groups. Examination of mRNAs of G6PD and ME suggested that the GSH-suppressing effect on enzyme induction occurred prior to and/or at transcriptional levels. Gel electrophoresis of G6PD indicated that low GSH status caused a decrease in reduced form and an increase in oxidized form of the enzyme, suggesting an accelerated turnover rate of the enzyme. In primary cultured hepatocytes, insulin response to induce G6PD activity was augmented in low GSH levels manipulated in the presence of buthionine sulfoximine. These findings indicated that elevation of the G6PD activity in low GSH levels was caused by amplified insulin response for expression of the enzyme and accelerated turnover rate of the enzyme molecule.

Altered expression profile of glycolytic enzymes during testicular ischemia reperfusion injury is associated with the p53/TIGAR pathway: effect of fructose 1,6-diphosphate

Background. Testicular ischemia reperfusion injury (tIRI) is considered the mechanism underlying the pathology of testicular torsion and detorsion. Left untreated, tIRI can induce testis dysfunction, damage to spermatogenesis and possible infertility. In this study, we aimed to assess the activities and expression of glycolytic enzymes (GEs) in the testis and their possible modulation during tIRI. The effect of fructose 1,6-diphosphate (FDP), a glycolytic intermediate, on tIRI was also investigated. Methods. Male Sprague-Dawley rats were divided into three groups: sham, unilateral tIRI, and tIRI + FDP (2 mg/kg). tIRI was induced by occlusion of the testicular artery for 1 h followed by 4 h of reperfusion. FDP was injected peritoneally 30 min prior to reperfusion. Histological and biochemical analyses were used to assess damage to spermatogenesis, activities of major GEs, and energy and oxidative stress markers. The relative mRNA expression of GEs was evaluated by real-time PCR. ELISA and immunohistochemistry were used to evaluate the expression of p53 and TP53-induced glycolysis and apoptosis regulator (TIGAR). Results. Histological analysis revealed tIRI-induced spermatogenic damage as represented by a significant decrease in the Johnsen biopsy score. In addition, tIRI reduced the activities of hexokinase 1, phosphofructokinase-1, glyceraldehyde 3-phosphate dehydrogenase, and lactate dehydrogenase C. However, mRNA expression downregulation was detected only for hexokinase 1, phosphoglycerate kinase 2, and lactate dehydrogenase C. ATP and NADPH depletion was also induced by tIRI and was accompanied by an increased Malondialdehyde concentration, reduced glutathione level, and reduced superoxide dismutase and catalase enzyme activities. The immunoexpression of p53 and TIGAR was markedly increased after tIRI. The above tIRI-induced alterations were attenuated by FDP treatment. Discussion. Our findings indicate that tIRI-induced spermatogenic damage is associated with dysregulation of GE activity and gene expression, which were associated with activation of the TIGAR/p53 pathway. FDP treatment had a beneficial effect on alleviating the damaging effects of tIRI. This study further emphasizes the importance of metabolic regulation for proper spermatogenesis.

Protective Effects of Carvedilol and Vitamin C against Azithromycin-Induced Cardiotoxicity in Rats via Decreasing ROS, IL1-β, and TNF-α Production and Inhibiting NF-κB and Caspase-3 Expression

The Food and Drug Administration recently warned of the fatal cardiovascular risks of azithromycin in humans. In addition, a recently published study documented azithromycin-induced cardiotoxicity in rats. This study aimed to justify the exact cardiovascular events accompanying azithromycin administration in rats, focusing on electrocardiographic, biochemical, and histopathological changes. In addition, the underlying mechanisms were studied regarding reactive oxygen species production, cytokine release, and apoptotic cell-death. Finally, the supposed protective effects of both carvedilol and vitamin C were assessed. Four groups of rats were used: (1) control, (2) azithromycin, (3) azithromycin + carvedilol, and (4) azithromycin + vitamin C. Azithromycin resulted in marked atrophy of cardiac muscle fibers and electrocardiographic segment alteration. It increased the heart rate, lactate dehydrogenase, creatine phosphokinase, malondialdehyde, nitric oxide, interleukin-1 beta (IL1-β), tumor necrosis factor alpha (TNF-α), nuclear factor kappa beta (NF-κB), and caspase-3. It decreased reduced glutathione, glutathione peroxidase, and superoxide dismutase. Carvedilol and vitamin C prevented most of the azithromycin-induced electrocardiographic and histopathological changes. Carvedilol and vitamin C decreased lactate dehydrogenase, malondialdehyde, IL1-β, TNF-α, NF-κB, and caspase-3. Both agents increased glutathione peroxidase. This study shows that both carvedilol and vitamin C protect against azithromycin-induced cardiotoxicity through antioxidant, immunomodulatory, and antiapoptotic mechanisms.

Vanillic Acid Ameliorates Cationic Bovine Serum Albumin Induced Immune Complex Glomerulonephritis in BALB/c Mice

Preclinical Research Vanillic acid (VA) is a dihydroxybenzoic acid derivative widely used as a flavoring agent. It has chemopreventive effects on experimentally-induced carcinogenesis and in ulcerative colitis. The object of the present study was to investigate the effects of VA, alone and in combination with methylprednisolone (MP), on cationic bovine serum albumin (cBSA induced immune-complex glomerulonephritis in female BALB/c mice. Pre-immunization was carried out with cBSA in BALB/c mice and repeated (cBSA, 13 mg/kg, 3 times/week, i.v.) for 6 weeks to induce glomerulonephritis which was confirmed by the presence of severe proteinuria. The effect of VA (50, 100, and 200 mg/kg, p.o.) and its combination with MP (12.5 mg/kg, p.o.) was assessed in the nephrotic disease model. Treatment with VA decreased inflammatory nephrotic injury as evidenced by decreased proteinuria, serum creatinine, blood urea nitrogen, serum IgG1 and TNF-α levels. Co-administration of VA with MP showed an improvement in the immunohistochemistry of glomerular nephrin and podocin. The present results indicate that VA has a nephroprotective effect in the management of autoimmune nephritis. Drug Dev Res 77 : 171-179, 2016.   © 2016 Wiley Periodicals, Inc.

Muscle wasting and aging: Experimental models, fatty infiltrations, and prevention

Identification of cost-effective interventions to maintain muscle mass, muscle strength, and physical performance during muscle wasting and aging is an important public health challenge. It requires understanding of the cellular and molecular mechanisms involved. Muscle-deconditioning processes have been deciphered by means of several experimental models, bringing together the opportunities to devise comprehensive analysis of muscle wasting. Studies have increasingly recognized the importance of fatty infiltrations or intermuscular adipose tissue for the age-mediated loss of skeletal-muscle function and emphasized that this new important factor is closely linked to inactivity. The present review aims to address three main points. We first mainly focus on available experimental models involving cell, animal, or human experiments on muscle wasting. We next point out the role of intermuscular adipose tissue in muscle wasting and aging and try to highlight new findings concerning aging and muscle-resident mesenchymal stem cells called fibro/adipogenic progenitors by linking some cellular players implicated in both FAP fate modulation and advancing age. In the last part, we review the main data on the efficiency and molecular and cellular mechanisms by which exercise, replacement hormone therapies, and β-hydroxy-β-methylbutyrate prevent muscle wasting and sarcopenia. Finally, we will discuss a potential therapeutic target of sarcopenia: glucose 6-phosphate dehydrogenase.

Succinate dehydrogenase activity regulates PCB3-quinone-induced metabolic oxidative stress and toxicity in HaCaT human keratinocytes

Polychlorinated biphenyls (PCBs) and their metabolites are environmental pollutants that are known to have adverse health effects. 1-(4-Chlorophenyl)-benzo-2,5-quinone (4-ClBQ), a quinone metabolite of 4-monochlorobiphenyl (PCB3, present in the environment and human blood) is toxic to human skin keratinocytes, and breast and prostate epithelial cells. This study investigates the hypothesis that 4-ClBQ-induced metabolic oxidative stress regulates toxicity in human keratinocytes. Results from Seahorse XF96 Analyzer showed that the 4-ClBQ treatment increased extracellular acidification rate, proton production rate, oxygen consumption rate and ATP content, indicative of metabolic oxidative stress. Results from a q-RT-PCR assay showed significant increases in the mRNA levels of hexokinase 2 (hk2), pyruvate kinase M2 (pkm2) and glucose-6-phosphate dehydrogenase (g6pd), and decreases in the mRNA levels of succinate dehydrogenase (complex II) subunit C and D (sdhc and sdhd). Pharmacological inhibition of G6PD-activity enhanced the toxicity of 4-ClBQ, suggesting that the protective function of the pentose phosphate pathway is functional in 4-ClBQ-treated cells. The decrease in sdhc and sdhd expression was associated with a significant decrease in complex II activity and increase in mitochondrial levels of ROS. Overexpression of sdhc and sdhd suppressed 4-ClBQ-induced inhibition of complex II activity, increase in mitochondrial levels of ROS, and toxicity. These results suggest that the 4-ClBQ treatment induces metabolic oxidative stress in HaCaT cells, and while the protective function of the pentose phosphate pathway is active, inhibition of complex II activity sensitizes HaCaT cells to 4-ClBQ-induced toxicity.

Microglial M1/M2 polarization and metabolic states

Microglia are critical nervous system-specific immune cells serving as tissue-resident macrophages influencing brain development, maintenance of the neural environment, response to injury and repair. As influenced by their environment, microglia assume a diversity of phenotypes and retain the capability to shift functions to maintain tissue homeostasis. In comparison with peripheral macrophages, microglia demonstrate similar and unique features with regards to phenotype polarization, allowing for innate immunological functions. Microglia can be stimulated by LPS or IFN-γ to an M1 phenotype for expression of pro-inflammatory cytokines or by IL-4/IL-13 to an M2 phenotype for resolution of inflammation and tissue repair. Increasing evidence suggests a role of metabolic reprogramming in the regulation of the innate inflammatory response. Studies using peripheral immune cells demonstrate that polarization to an M1 phenotype is often accompanied by a shift in cells from oxidative phosphorylation to aerobic glycolysis for energy production. More recently, the link between polarization and mitochondrial energy metabolism has been considered in microglia. Under these conditions, energy demands would be associated with functional activities and cell survival and thus, may serve to influence the contribution of microglia activation to various neurodegenerative conditions. This review examines the polarization states of microglia and their relationship to mitochondrial metabolism. Additional supporting experimental data are provided to demonstrate mitochondrial metabolic shifts in primary microglia and the BV-2 microglia cell line induced under LPS (M1) and IL-4/IL-13 (M2) polarization.

Neuroprotective Effect of Lycopene Against PTZ-induced Kindling Seizures in Mice: Possible Behavioural, Biochemical and Mitochondrial Dysfunction

Oxidative stress and mitochondrial dysfunction are the major contributing factors in the pathophysiology of various neurological disorders. Recently, antioxidant therapies aimed at reducing oxidative stress gained a considerable attention in epilepsy treatment. Lycopene, a carotenoid antioxidant, has received scientific interest in recent years. So, the present study has been designed to evaluate the neuroprotective effect of lycopene against the pentylenetetrazol (PTZ)-induced kindling epilepsy. Laca mice received lycopene (2.5, 5 and 10 mg/kg) and sodium valproate for a period of 29 days and PTZ (40 mg/kg i.p (Intraperitoneal)) injection on alternative days. Various behavioural (kindling score), biochemical parameters (lipid peroxidation, superoxide dismutase, reduced glutathione, catalase and nitrite) and mitochondrial enzyme complex activities (I, II and IV) were assessed in the brain. Results depicted that repeated administration of a sub-convulsive dose of PTZ (40 mg/kg) significantly increased kindling score, oxidative damage and impaired mitochondrial enzyme complex activities (I, II and IV) as compared with naive animals. Lycopene (5 and 10 mg/kg) and sodium valproate (100 mg/kg) treatment for a duration of 29 days significantly attenuated kindling score, reversed oxidative damage and restored mitochondrial enzyme complex activities (I, II and IV) as compared with control. Thus, present study demonstrates the neuroprotective potential of lycopene in PTZ-induced kindling in mice.

Kinetic analysis of gluconate phosphorylation by human gluconokinase using isothermal titration calorimetry

Gluconate is a commonly encountered nutrient, which is degraded by the enzyme gluconokinase to generate 6-phosphogluconate. Here we used isothermal titration calorimetry to study the properties of this reaction. ΔH, KM and kcat are reported along with substrate binding data. We propose that the reaction follows a ternary complex mechanism, with ATP binding first. The reaction is inhibited by gluconate, as it binds to an Enzyme-ADP complex forming a dead-end complex. The study exemplifies that ITC can be used to determine mechanisms of enzyme catalyzed reactions, for which it is currently not commonly applied.

Cross-omics comparison of stress responses in mesothelial cells exposed to heat- versus filter-sterilized peritoneal dialysis fluids

Recent research suggests that cytoprotective responses, such as expression of heat-shock proteins, might be inadequately induced in mesothelial cells by heat-sterilized peritoneal dialysis (PD) fluids. This study compares transcriptome data and multiple protein expression profiles for providing new insight into regulatory mechanisms. Two-dimensional difference gel electrophoresis (2D-DIGE) based proteomics and topic defined gene expression microarray-based transcriptomics techniques were used to evaluate stress responses in human omental peritoneal mesothelial cells in response to heat- or filter-sterilized PD fluids. Data from selected heat-shock proteins were validated by 2D western-blot analysis. Comparison of proteomics and transcriptomics data discriminated differentially regulated protein abundance into groups depending on correlating or noncorrelating transcripts. Inadequate abundance of several heat-shock proteins following exposure to heat-sterilized PD fluids is not reflected on the mRNA level indicating interference beyond transcriptional regulation. For the first time, this study describes evidence for posttranscriptional inadequacy of heat-shock protein expression by heat-sterilized PD fluids as a novel cytotoxic property. Cross-omics technologies introduce a novel way of understanding PDF bioincompatibility and searching for new interventions to reestablish adequate cytoprotective responses.

LKB1 Inactivation Elicits a Redox Imbalance to Modulate Non-small Cell Lung Cancer Plasticity and Therapeutic Response

LKB1 regulates both cell growth and energy metabolism. It remains unclear how LKB1 inactivation coordinates tumor progression with metabolic adaptation in non-small cell lung cancer (NSCLC). Here in Kras(G12D);Lkb1(lox/lox) (KL) mouse model, we reveal differential reactive oxygen species (ROS) levels in lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC). ROS can modulate ADC-to-SCC transdifferentiation (AST). Further, pentose phosphate pathway deregulation and impaired fatty acid oxidation collectively contribute to the redox imbalance and functionally affect AST. Similar tumor and redox heterogeneity also exist in human NSCLC with LKB1 inactivation. In preclinical trials toward metabolic stress, certain KL ADC can develop drug resistance through squamous transdifferentiation. This study uncovers critical redox control of tumor plasticity that may affect therapeutic response in NSCLC.