G6PDH Activity Research Articles

Carbohydrate Metabolic Compensation Coupled to High Tolerance to Oxidative Stress in Ticks

Reactive oxygen species (ROS) are natural byproducts of metabolism that have toxic effects well documented in mammals. In hematophagous arthropods, however, these processes are not largely understood. Here, we describe that Rhipicephalus microplus ticks and embryonic cell line (BME26) employ an adaptive metabolic compensation mechanism that confers tolerance to hydrogen peroxide (H2O2) at concentrations too high for others organisms. Tick survival and reproduction are not affected by H2O2 exposure, while BME26 cells morphology was only mildly altered by the treatment. Furthermore, H2O2-tolerant BME26 cells maintained their proliferative capacity unchanged. We evaluated several genes involved in gluconeogenesis, glycolysis, and pentose phosphate pathway, major pathways for carbohydrate catabolism and anabolism, describing a metabolic mechanism that explains such tolerance. Genetic and catalytic control of the genes and enzymes associated with these pathways are modulated by glucose uptake and energy resource availability. Transient increase in ROS levels, oxygen consumption, and ROS-scavenger enzymes, as well as decreased mitochondrial superoxide levels, were indicative of cell adaptation to high H2O2 exposure, and suggested a tolerance strategy developed by BME26 cells to cope with oxidative stress. Moreover, NADPH levels increased upon H2O2 challenge, and this phenomenon was sustained mainly by G6PDH activity. Interestingly, G6PDH knockdown in BME26 cells did not impair H2O2 tolerance, but generated an increase in NADP-ICDH transcription. In agreement with the hypothesis of a compensatory NADPH production in these cells, NADP-ICDH knockdown increased G6PDH relative transcript level. The present study unveils the first metabolic evidence of an adaptive mechanism to cope with high H2O2 exposure and maintain redox balance in ticks.

Nanocomposite packaging regulate respiration and energy metabolism in Flammulina velutipes

Energy metabolism is accompanied with postharvest senescence, deterioration and physiological disorder in Flammulina velutipes. In this study, nanocomposite packaging material (Nano-PM) inhibited rapid respiration thus preventing accumulation of reactive oxygen species (ROS). In comparison to the normal packaging material (Normal-PM) and no packaging (No-PM), Nano-PM elevated NADP and NADPH contents by increasing the key enzymes in pentose phosphate pathway (PPP), NADK and G6PDH activities, which was due to ROS removal. Moreover, the package enhanced mitochondrial ATPase activity. Regulation of PPP pathway and elevation of ATPase activity was the main reason for the maintenance of mitochondria membrane and structure integrity. Therefore, Nano-PM maintained sufficient ATP content and energy charge by protecting mitochondria structure and regulating electron transfer of mitochondrial respiratory. Overall, Nano-PM maintained energy metabolism by delaying apoptosis and swelling of mitochondria, thus, it alleviated postharvest senescence of F. velutipes.

Heteroexpression and functional characterization of glucose 6-phosphate dehydrogenase from industrial Aspergillus oryzae.

The engineered Aspergillus oryzae has a high NADPH demand for the xylose utilization and overproduction of target metabolites. Glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) is one of two key enzymes in the oxidative part of the pentose phosphate pathway, which is the main enzyme responding for the NADPH regeneration. The open reading frame and cDNA of putative A. oryzae G6PDH (AoG6PDH) were obtained, which was followed by heterogeneous expression in Escherichia coli and was purified as a his6-tagged protein presently. The purified protein was characterized to be in possession of G6PDH activity with a molecular mass of 118.0 kDa. The enzyme displayed the maximal activity at pH 7.5 and the optimal temperature was 50 °C. This enzyme had half-life time of 33.3 min at 40 °C. Kinetics assay showed that AoG6PDH was strictly dependent on NADP+ (Km = 6.3 μM, kcat = 1000.0 s-1, kcat/Km =158.7 s-1·μM-1) as cofactor. The Km and kcat/Km value of glucose-6-phosphate were 109.7 s-1·μM-1 and 9.1 -1·μM-1 respectively. Initial velocity and product inhibition analyses indicated the catalytic reaction followed a two-substrate steady-state ordered BiBi mechanism, where NADP+ was the first substrate bound to the enzyme and NADPH was the second product released from the catalytic complex. The established kinetic model could be applied in further regulation of the pentose phosphate pathway and NADPH regeneration of A. oryzae for improving the xylose utilization and yields of valued metabolites.

The relationship between carbon and nitrogen metabolism in cucumber leaves acclimated to salt stress.

The study examines the effect of acclimation on carbon and nitrogen metabolism in cucumber leaves subjected to moderate and severe NaCl stress. The levels of glucose, sucrose, NADH/NAD+-GDH, AspAT, AlaAT, NADP+-ICDH, G6PDH and 6GPDH activity were determined after 24 and 72 hour periods of salt stress in acclimated and non-acclimated plants. Although both groups of plants showed high Glc and Suc accumulation, they differed with regard to the range and time of accumulation. Acclimation to salinity decreased the activities of NADP+-ICDH and deaminating NAD+-GDH compared to controls; however, these enzymes, together with the other examined parameters, showed elevated values in the stressed plants. The acclimated plants showed higher G6PDH activity than the non-acclimated plants, whereas both groups demonstrated similar 6PGDH activity. The high activities of NADH-GDH, AlaAT and AspAT observed in the examined plants could be attributed to a high demand for glutamate. The observed changes may be required for the maintenance of correct TCA cycle activity, and acclimation appeared to positively influence these adaptive processes.

Soybean meal replacement by corn distillers dried grains with solubles (DDGS) and exogenous non-starch polysaccharidases supplementation in diets for gilthead seabream (Sparus aurata) juveniles

A growth trial was conducted to evaluate the effect of dietary plant-protein replacement by corn distillers dried grains with solubles (DDGS), and of exogenous carbohydrases supplement (Natugrain®TS, BASF) in gilthead seabream (Sparus aurata) juveniles. For that purpose, a basal diet was formulated with 35% of fish meal and 20% soybean meal (SBM) as main protein sources. Two other diets were formulated incorporating 15 or 35% of DDGS, replacing 37.5% or 100% of SBM (diets DDGS15 and DDGS35, respectively). Another diet was formulated similar to diet DDGS35 and supplemented with 0.1% of a commercial non-starch polysaccharidases complex, Natugrain®TS, BASF (CHOase; diet DDGS35ENZ). Triplicate groups of fish (IBW = 15 ± 1 g) were fed the experimental diets for 67 days at 22 °C. At the end of the trial, growth performance, voluntary feed intake, feed efficiency, protein and energy retention were not affected by dietary DDGS incorporation. Dietary CHOase supplementation also did not affect growth performance, but increased feed efficiency, nitrogen and energy retention. Dietary inclusion of DDGS tended to decrease production cost (€ per kg of fish), and dietary CHOase supplementation further reduced production cost, which was significantly lower with diet DDGS35ENZ than with the basal diet. Whole-body composition, hepatosomatic and visceral indexes were not affected by the dietary inclusion of DDGS, though a trend was noticed for a decrease of whole-body lipid, energy, and visceral index with the increase dietary DDGS. Plasma glucose, protein, albumin, and globulins levels were similar among diets, whereas plasma triglycerides increased, and cholesterol decreased with the increase of dietary DDGS. Hepatic glycolytic enzymes activities (hexokinase and glucokinase) were similar among groups, while gluconeogenic (fructose biphosphatase) activity, GDH and ASAT activities decreased with the increase of dietary DDGS. The hepatic activity of oxidative stress-related enzymes catalase and superoxide dismutase were not affected by dietary treatments, but G6PDH and GR activities decreased, and liver lipid peroxidation increased with dietary DDGS level. Dietary CHOase supplementation decreased overall lipid peroxidation.Overall, results of this study indicate that total replacement of SBM by DDGS in diets for gilthead seabream did not compromise growth performance or feed utilization efficiency, while supplementation of DDGS-based diet with exogenous carbohydrases improved feed utilization efficiency and economic efficiency ratio.

Mechanism(s) of action of heavy metals to investigate the regulation of plastidic glucose-6-phosphate dehydrogenase

The regulation of recombinant plastidic glucose-6P dehydrogenase from Populus trichocarpa (PtP2-G6PDH - EC 1.1.1.49) was investigated by exposing wild type and mutagenized isoforms to heavy metals. Nickel and Cadmium caused a marked decrease in PtP2-G6PDH WT activity, suggesting their poisoning effect on plant enzymes; Lead (Pb++) was substantially ineffective. Copper (Cu++) and Zinc (Zn++) exposition resulted in strongest decrease in enzyme activity, thus suggesting a physiological competition with Magnesium, a well-known activator of G6PDH activity. Kinetic analyses confirmed a competitive inhibition by Copper, and a mixed inhibition by (Cd++). Mutagenized enzymes were differently affected by HMs: the reduction of disulfide (C175–C183) exposed the NADP+ binding sites to metals; C145 participates to NADP+ cofactor binding; C194 and C242 are proposed to play a role in the regulation of NADP+/NADPH binding. Copper (and possibly Zinc) is able to occupy competitively Magnesium (Mg++) sites and/or bind to NADP+, resulting in a reduced access of NADP+ sites on the enzyme. Hence, heavy metals could be used to describe specific roles of cysteine residues present in the primary protein sequence; these results are discussed to define the biochemical mechanism(s) of inhibition of plant plastidic G6PDH.

Colocynth (Citrullus colocynthis) Flesh Extract Suppresses Adipogenesis by Down-Regulating Adipogenic Transcription Factors and Their Target Genes in 3T3-L1 Preadipocytes

Citrullus colocynthis, a member of the Cucurbitaceae family, is widely distributed in North Africa. The fruits are recognized for their wide range of medicinal uses and promising pharmaceutical potential. The present study aimed to investigate the anti-obesity effect of the ethanol extract of colocynth flesh (FCEE) in 3T3-L1 cells following treatment at different doses. The viability of 3T3-L1 preadipocytes was analyzed via MTT assay and triglycerides were stained with Oil red O to assess lipid accumulation. Additionally, adipogenesis-related gene expression was quantified via qRT-PCR. FCEE (0 - 150 μg/mL) dose-dependently suppressed intracellular triglyceride accumulation during the adipogenesis by 23% and 66% at 100 and 150 μg/mL, respectively, but did not affect cell viability. Analysis of the time-dependence of the effect of FCEE demonstrated that the greatest anti-adipogenic activity was observed during the early stages of differentiation. FCEE also decreased GPDH activity in a dose-dependent manner, with 98% decrease observed at 150 μg/mL. In addition, at same range of FCEE concentrations, the main transcription factors, including CCAAT/enhancer binding protein α (C/EBPα), peroxisome proliferator activated receptor γ (PPARγ), and sterol regulatory element-binding protein 1c (SREBP-1c), were downregulated by 90%, 89%, and 89%, respectively at 150 μg/mL. As these are the master regulators of adipogenesis. The inhibition of their downstream target genes was also observed. Colocynth may be useful in the treatment of obesity owing to its powerful effects on fat, which result in changes to adipocyte differentiation and fat mobilization.

Biochemical and molecular responses in oysters Crassostrea brasiliana collected from estuarine aquaculture areas in Southern Brazil

Biochemical and molecular responses were evaluated in oysters Crassostrea brasiliana collected from three oyster farms, at Guaratuba Bay, southern Brazil, forming a pollutant gradient: Farm 1 (reference site - farther from the urban area), Farm 2 (intermediate site) and Farm 3 (nearest to the urban area). Oxidative stress markers, DNA damage and transcript levels of CYP2AU1, CYP2-like1, CYP2-like2, SULT-like, GPx-like, SOD-like, CAT-like, GSTmicrosomal-like, GSTomega-like, FABP-like and ALAd-like genes were analyzed in the gills. The levels of polycyclic aromatic hydrocarbons, linear alkylbenzenes and polychlorinated biphenyls were also evaluated in the soft tissues of the oysters and in the sediment of the Farms. Higher GSTomega-like, CYP2AU1 and FABP-like transcript levels, GR and G6PDH activities and lipid peroxidation levels were observed in oysters from Farms 2 and 3, suggesting pollutant effects on oysters. Alterations in oxidative stress markers also suggest a response against a prooxidant condition in C. brasiliana due to pollutant effects.

Activated-farnesoid X receptor (FXR) expressed in human sperm alters its fertilising ability.

The farnesoid X receptor alpha (FXR) is a bile acid sensor activated by binding to endogenous bile acids including chenodeoxycholic acid (CDCA). Although, FXR is expressed in male reproductive tissue, the relevance of the receptor on reproduction is scarcely known. Here, we demonstrated the FXR presence and its action on several human sperm features. Western blot and immunofluorescence assays evidenced the FXR expression in human spermatozoa and the localisation in the middle piece. CDCA increasing concentrations and GW4064, synthetic ligand of FXR, were used to study the FXR influence on sperm motility, survival, capacitation, acrosome reaction and on glucose as well as lipid metabolism. Interestingly, our data showed that increasing concentrations of CDCA negatively affected sperm parameters, while the receptor blockage by (Z)-Guggulsterone and by the anti-FXR Ab reversed the effects. Intriguingly, elevated CDCA levels increased triglyceride content, while lipase and G6PDH activities were reduced with respect to untreated samples, thus impeding the metabolic reprogramming typical of the capacitated sperm. In conclusion, in this study, we demonstrated for the first time a novel target for FXR and that the activated receptor alters the acquisition of sperm fertilising ability. We showed that sperm itself express the FXR and it is responsive to specific ligands of the receptor; therefore, bile acids influence this cell both in male and in female genital tracts. It might be hypothesized that bile acid levels could be involved in infertility with idiopathic origin as these compounds are not systematically measured in men undergoing medically assisted procreation.

Molecular and cellular effects of temperature in oysters Crassostrea brasiliana exposed to phenanthrene

Exposure of aquatic organisms to polycyclic aromatic hydrocarbons (PAH), such as phenanthrene (PHE), may increase the production of reactive oxygen species (ROS) and cause changes in the biotransformation systems. In addition, changes in water temperature can cause adverse effects in the organisms. Estuarine species, like the oyster Crassostrea brasiliana, can adapt and tolerate temperature variation. To evaluate the influence of temperature on biological responses of C. brasiliana exposed to PHE, oysters were maintained at three temperatures (18, 24 and 32 °C) for 15 days and co-exposed afterwards to 100 μg.L−1 of PHE for 24 and 96 h. Levels of PHE in the water and oyster tissues were determined, respectively after 24 and 96 h. In addition, thermal stress, biotransformation and oxidative stress-related genes were analyzed in oyster gills, together with the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferases (GST) and levels of lipid peroxidation. Oyster accumulated significant levels of PHE. HSP70-like transcripts were affected by PHE exposure only at 32 °C. Transcript levels of cytochrome P450 isoforms (CYP2-like2 and CYP2AU1) were down-regulated in oysters exposed to PHE for 24 h at 32 °C. GSTΩ-like transcript levels were also down-regulated in the PHE-exposed group at 32 °C. After 96 h, CYP2-like2 transcripts were higher in the PHE exposed groups at 32 °C. Oysters kept at 18 °C showed higher levels of SOD-like transcripts, together with higher GST, GPx and G6PDH activities, associated to lower levels of lipoperoxidation. In general the biological responses evaluated were more affected by temperature, than by co-exposure to PHE.

TOXICITY OF ATRAZINE AND RELATED TO TESTICULAR, TISSUE DAMAGING ENZYME LEVELS IN POECILIA SPHENOPS

Objective: This study was designed to evaluate the toxic effects of Atrazine (ATZ) on the enzyme levels in Poecilia sphenops.Methods: The cytosolic testicular enzyme and tissue-damaging enzyme activity were measured in Poecilia sphenops was exposed to 3 sub-lethal concentrations (1.25, 2.5 and 5 mg/l) of atrazine for 100days and control was also maintained. The toxic effects of ATZ to Poecilia sphenops were assessed through testicular marker enzyme, tissue-damaging enzyme level.Results: The activities of testicular functional enzyme ALP, ACP, SDH, LDH, G6PDH and tissue-damaging the activities of glutamate oxaloacetic transaminase (GOT) and glutamate pyruvic transaminase (GPT) activity levels were altered in treated groups compared with that of the control.Conclusion: This study demonstrates that atrazine induces tissue damage in terms of enhanced enzyme activity and testicular enzyme activity in Poecilia sphenops. Atrazine has toxicity to the reproductive system in Poecilia sphenops.

Effects of acclimation to high environmental temperatures on intermediary metabolism and osmoregulation in the sub-Antarctic notothenioid Eleginops maclovinus

Eleginops maclovinus is a sub-Antarctic fish endemic to the South American coast and is a monotypic species of the Eleginopidae family. A scarce amount of scientific information exists regarding the effects of temperature on E. maclovinus physiology. In this study, E. maclovinus specimens were acclimated for 2 weeks at 10 °C (control), 14, and 18 °C. Posterior assessments were performed for the intermediary metabolism of carbohydrates, lipids, and amino acids (in the plasma, liver, gills, and kidney) and on the osmoregulatory capacity [plasma osmolality and gill, kidney, and foregut Na+, K+-ATPase (NKA) activities]. In the plasma, only lactate and total amino acid levels were affected by the temperature. NKA activity presented a linear relationship with the increased temperatures. The liver exhibited no change in the carbohydrates metabolism, but the glycogen/glucose metabolite levels did differ. Amino acid metabolism showed a direct relationship between temperature and GDH and Asp-AT activities, and an inverse relationship between temperature and Ala-AT activity. Lipid metabolism was similar to Ala-AT. In the gills, carbohydrate metabolism (G6PDH and HK activities) presented a direct relationship with the increased temperatures. In the kidney, carbohydrate metabolism (only G6PDH activity) was greater at higher temperatures, and amino acid metabolism (GDH activity) showed a direct relationship with temperature. Lipid metabolism (G3PDH activity) was greatest at 14 °C, presenting significant differences compared to 10 °C. The obtained results suggest that E. maclovinus can acclimate to the projected thermal increase of climate change, with a reorganization of the intermediary metabolism components being tissue-dependent and osmoregulatory effects being affected by NKA activity and greater rates of nitrogenous waste extrusion.

Effects of starvation and refeeding on expression of ghrelin and leptin gene with variations in metabolic parameters in Labeo rohita fingerlings

A study was conducted to evaluate the effect of starvation and refeeding on ghrelin and leptin gene expression in Labeo rohita fingerlings. Further, the variations in digestive, metabolic enzymes and metabolites such as glucose, glycogen and lipids were also revealed. An experimental trial of 15days was carried out, with 7days of starvation and then refeeding up to 15days. Sampling was done at different time intervals of 0, 0.5, 1, 2, 3, 5, 7, 10 and 15th day of the experiment. The ghrelin gene expression levels increased significantly (p<0.05) up to 7th day and decreased after refeeding. Leptin levels showed the opposite trend with decline in expression levels during starvation and declined to the levels of control after refeeding. The activities of digestive enzymes protease, amylase and lipase enzymes were significantly lowest (p<0.05) on 7th day of starvation and they increased after refeeding the fishes. Hexokinase and G6PDH activities were decreased with days of starvation while LDH and G6Pase significantly increased with starvation. Glycogen showed significant (p<0.05) reduction during starvation and relapsed to the level of control after refeeding, revealing the role of glycogen stores during starvation. The present study revealed the orexigenic role of ghrelin and anorexigenic role of leptin during starvation and refeeding in L. rohita which aids in maintaining the energy homeostasis through regulating nutrient metabolism. The study also concludes that L. rohita can sustain 7 days of starvation with the aid of metabolic and endocrine regulation of energy homeostasis.

Contrasting patterns of energy metabolism in northern vs southern peripheral European flounder populations exposed to temperature rising and hypoxia

A two months common garden experiment was carried out to explore the potential differences of energy metabolism in northern core (France, 50°N and 47°N) vs southern peripheral (Portugal, 41°N) populations of European flounder Platichthys flesus, submitted to cold condition (CC: water temperature = 10 °C) and to warm and hypoxic condition (WHC: water temperature = 22 °C, and moderate hypoxia with O2 saturation = 40% during the last 6 days). Convergent growth rates (in length) were observed in the different populations and conditions, when the southern peripheral population of Portugal did not grow under cold conditions. A general reduction in liver lipid storage was observed in all populations subjected to WHC when compared to CC, whereas muscle lipid storage was unaffected. The thermal and hypoxia treatment induced changes in muscle phospholipids (PL) ratios: phosphatidylserine/PL, phosphatidylinositol/PL, between northern and southern populations. Fish from northern estuaries displayed marked anaerobiosis in WHC (increased liver LDH activity) vs marked aerobiosis under CC (higher muscle CS and CCO activities). Contrariwise, fish from the southern estuary displayed equilibrium between anaerobiosis and aerobiosis activities in WHC. Flounders from the southern population exhibited generally lower G6PDH activity (proxy for anabolism and for defense against oxidative damage), tissue-specific anaerobiosis response (muscle LDH activity) and lower CS and CCO muscle activities (aerobiosis markers) when compared to northern populations. Globally, these inter-population differences in bioenergetics suggest that southern peripheral vs northern core populations have developed differential capacity to cope with interacting stressors and that much of this variation is more likely due to local adaptation.

Fluctuations in water temperature affected waterborne cadmium toxicity: Hematology, anaerobic glucose pathway, and oxidative stress status of Nile tilapia, Oreochromis niloticus (L.)

The increase of water temperature has already been observed because of global climatic changes. Beside fluctuations in temperature, aquatic ecosystems may be stressed by the discharge of heated wastewater and toxic chemicals such as heavy metals. Therefore, this study was conducted to investigate effects of water temperature and/or waterborne cadmium (Cd) on hematology (red blood cells, RBCs; hematocrit, Ht; and hemoglobin, Hb), anaerobic glucolytic metabolism (lactate dehydrogenase, LDH; phosphofructokinase, PFK; and pyruvate kinase, PK) as well as of the pentose pathway (glycose-6-phosphate dehydrogenase, G6PDH), and oxidative defense (sodium dismutase, SOD; catalase, CAT; glutathione peroxidase, GPx and Glutathion transferase, GST) of Nile tilapia. Fish (26.0±0.38g) were acclimated to 20, 24, 28, or 32°C and co-exposed to 0.0 or 0.5mgCd/L for 8weeks in triplicates. Two-way ANOVA revealed that all variables were significantly affected by water temperature, Cd exposure, and their interaction. Hematological variables increased significantly by increasing water temperature up to 28°C, after which they decreased significantly at 32°C. Additionally, these variables were lower in Cd-exposed fish group than those of Cd-free ones. Irrespective to Cd exposure, there are no significant differences in hematological variables in fish reared at 24 and 28°C. Hepatic glycolytic and oxidative system enzymes activities increased with increasing water temperature up to 32°C. In Cd-free fish groups, there are no significant differences in activities of these enzymes in fish reared at 24 and 28°C. The Cd exposure caused significant increases in the activities of LDH and PK and significant decreases in PFK and G6PDH activities with increasing water temperature compared to Cd-free fish groups. Meanwhile, Cd-exposed fish showed highest activities of oxidative stress enzymes as compared to Cd-free fish groups. The changes in hepatic enzymes suggest that their activities were optimized when fish were reared at 24–28°C. Furthermore, at 32°C, the overall increment in the hepatic enzyme activities of Cd-exposed fish seems to be contributed to enhance Cd toxic effects.

Perilla frutescens var acuta inhibits differentiation of 3T3‐L1 preadipocytes by downregulation of lipogenic pathway

Condiments are substances which are used to add flavors in foods and they have also been used in traditional medicines in various parts of the world. Perilla is one of the widely used condiments in Asian countries including China, Japan and South Korea. Previous studies reported that Perilla frutescens var britton (Green perilla) have antioxidant, antiallergic, antiobesity and neuroprotective effects. This study aimed to investigate the effect of Perilla frutescens var acuta (purple perilla) leaves on differentiation of 3T3‐L1 preadipocytes. The sample did not show any cytotoxicity. After inducing differentiation, with or without different concentrations of the sample for a period of eight days, the cells were extracted for quantification of triglycerides and mRNA expression of adipogenic transcription factors and enzymes. Treatment with perilla extract reduced the triglyceride accumulation dose dependently which was evident from the TG quantification as well as Oil Red O staining of lipid droplets. The mRNA expressions of transcription factors like PPARγ, C/EBPα and lipogenic enzymes like ACC, FAS, aP2 were significantly reduced in treated cells. GPDH activity assay also showed similar results. In conclusion, the results of this study elucidated that perilla leaf extract prevents accumulation of lipid and differentiation of 3T3‐L1 preadipocytes by downregulation of lipogenic pathway. Further studies are to be conducted to find the potential antiobesity effect of purple perilla on rodents.Support or Funding Information[This research was financially supported by the Ministry of Trade, Industry, and Energy (MOTIE), Korea, under the “Regional Specialized Industry Development Program” supervised by the Korea Institute for Advancement of Technology (KIAT)]

Particulate metal bioaccessibility in physiological fluids and cell culture media: Toxicological perspectives

According to the literature, tiny amounts of transition metals in airborne fine particles (PM2.5) may induce proinflammatory cell response through reactive oxygen species production. The solubility of particle-bound metals in physiological fluids, i.e. the metal bioaccessibility is driven by factors such as the solution chemical composition, the contact time with the particles, and the solid-to-liquid phase ratio (S/L). In this work, PM2.5-bound metal bioaccessibility was assessed in various physiological-like solutions including cell culture media in order to evidence the potential impact on normal human bronchial epithelial cells (NHBE) when studying the cytotoxicity and inflammatory responses of PM2.5 towards the target bronchial compartment. Different fluids (H2O, PBS, LHC-9 culture medium, Gamble and human respiratory mucus collected from COPD patients), various S/L conditions (from 1/6000 to 1/100,000) and exposure times (6, 24 and 72h) were tested on urban PM2.5 samples. In addition, metals’ total, soluble and insoluble fractions from PM2.5 in LHC-9 were deposited on NHBE cells (BEAS-2B) to measure their cytotoxicity and inflammatory potential (i.e., G6PDH activity, secretion of IL-6 and IL-8). The bioaccessibility is solution-dependent. A higher salinity or organic content may increase or inhibit the bioaccessibiliy according to the element, as observed in the complex mucus matrix. Decreasing the S/L ratio also affect the bioaccessibility depending on the solution tested while the exposure time appears less critical. The LHC-9 culture medium appears to be a good physiological proxy as it induces metal bioaccessibilities close to the mucus values and is little affected by S/L ratios or exposure time. Only the insoluble fraction can be linked to the PM2.5-induced cytotoxicity. By contrast, both soluble and insoluble fractions can be related to the secretion of cytokines. The metal bioaccessibility in LHC-9 of the total, soluble, and insoluble fractions of the PM2.5 under study did not explain alone, the cytotoxicity nor the inflammatory response observed in BEAS-2B cells. These findings confirm the urgent need to perform further toxicological studies to better evaluate the synergistic effect of both bioaccessible particle-bound metals and organic species.

Ethanol-induced male infertility: Effects of aqueous leaf extract of Tetracarpidium conophorum.

This study investigated the effects of Tetracarpidium conophorum leaf extract on infertility induced by ethanol in male rats. Thirty rats were randomly divided into six groups of five animals each: Group 1 (positive control) received 0.9% saline only; Group 2 (ethanol alone) were given only 30% ethanol orally at 7ml/kg body weight per day, thrice in a week; groups 3, 4 and 5 were given ethanol and co-treated with 50, 500 and 1,000mg/kg body weight of leaf extract, respectively, while Group 6 was given ethanol and co-treated with a fertility drug, clomiphene citrate. Ethanol treatment resulted in significant (p<.05) decrease in LDH activity, G-6PDH activity, glycogen content, 3β and 17β HSD activities and testicular and epididymal Zn and Se contents and furthermore decrease in testicular sperm count, viability and marked increment in total sperm abnormalities, rate of sperm analysis parameters and consequently decreased reproductive hormone levels. Interestingly, co-administration of ethanol with either T.conophorum extract or drug almost ameliorated the toxic assault imposed by ethanol on reproductive organs and improved seminal qualities of the rats.

Taurine Recovers Testicular Steroidogenesis and Spermatogenesis in Streptozotocin-Induced Diabetic Rats.

A great deal of investigations have verified that diabetic male reproductive impairment is associated with the dysfunction of testicular steroidogenesis and spermatogenesis resulted from insulin deficiency and hyperglycaemia-induced oxidative stress. It has been identified taurine is profitable for diabetes mellitus and diabetic implications through its insulin-like and islet cells protective activity. Furthermore, our previous studies found that taurine could increase testicular antioxidative ability, stimulate the endocrine activity of hypothalamic-pituitary-testicular axis, elevate testosterone level, raise sperm quality, suppress the deterioration of testicular function. Accordingly, we hypothesized that taurine may have beneficial effects on testicular dysfunction under diabetic mellitus status. Here, we investigated the effects of taurine on testicular steroidogenesis and spermatogenesis in streptozotocin (STZ)-induced type I diabetic rats. We observed that taurine treatment can markedly increase the body and testis weights, testicular SDH and G6PDH activities, decrease the serum fasting glucose concentration of diabetic rats. Serum contents of GnRH, LH, FSH, T, and testicular StAR, 3β-HSD, 17β-HSD mRNA expression levels were also obviously raised by taurine administration, indicating that taurine can improve testicular steroidogenesis in diabetic animals. Finally, we found taurine supplementation effectively elevated the sperm count and motility, reduced sperm abnormality, suggesting that taurine can increase the testicular spermatogenesis function of diabetic rat. In summary, the present data indicated that taurine can rescue the function of testicular steroidogenesis and spermatogenesis in STZ-induced type I diabetic rats possibly by increasing the endocrine activity of hypothalamic-pituitary-testicular axis.

Highly active antiretroviral therapy dysregulates proliferation and differentiation of human pre-adipocytes.

AIMTo investigate the mechanism(s) by which potential effects of multi-drug highly-active antiretroviral therapy contributes to lipodystrophy syndrome.METHODSPreadipocytes from healthy donors were assessed for proliferation and differentiation in the presence of nucleoside reverse transcriptase inhibitors (NRTIs), nonnucleoside reverse transcriptase inhibitors (NNRTIs), and protease inhibitors (PIs) individually and in combination. Effects on proliferation were assessed with a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay and effects on differentiation were assessed from glycerol-3-phosphate dehydrogenase (GP DH) activity and quantitation of Oil Red O staining for intracellular lipid. Data were analyzed with a randomized block ANOVA with post-hoc Fisher’s Least Significant Difference test.RESULTSPreadipocyte proliferation was inhibited by a combination of NNRTI + NRTI (14% at 48 h, P < 0.001) and PI + NRTI (19% at 48 h, P < 0.001) with additional suppression when ritonavir (RTV) was added (26% at 48 h). The drug combination of atazanavir (ATV) + RTV + emtricitabine (FTC) + tenofovir (TDF) had the greatest inhibitory effect on proliferation at 48 h. Preadipocyte differentiation was most significantly reduced by the efavirenz + FTC + TDF assessed either by GPDH activity (64%) or lipid accumulation (39%), P < 0.001. Combining NRTIs with a PI (ATV + FTC + TDF) significantly suppressed differentiation (GPDH activity reduced 29%, lipid accumulation reduced by 19%, P < 0.01). This effect was slightly greater when a boosting amount of RTV was added (ATV + FTC + TDF + RTV, P < 0.001).CONCLUSIONAlthough combination antiretroviral therapy is clinically more efficacious than single drug regimens, it also has a much greater inhibitory effect on preadipocyte proliferation and differentiation.