Hydrogen peroxide signaling modulates neuronal differentiation via microglial polarization and Wnt/ß-catenin pathway.

OBJECTIVE: Reactive oxygen species (ROS) are generated within the cell and serve as second messengers in fundamental cellular processes under physiologic conditions. Although the deleterious effects of high-level ROS associated with oxidative stress are well established, it is unclear how the developing brain reacts to redox changes. Our aim is to investigate how redox alteration affects neurogenesis and the mechanism that underlies it. MATERIALS AND METHODS: We investigated in vivo microglial polarization and neurogenesis in zebrafish after hydrogen peroxide (H2O2) incubation. To quantify intracellular H2O2 levels in vivo, a transgenic zebrafish line that expresses Hyper and termed Tg(actb2:hyper3)ka8 was used. Then, in vitro studies with N9 microglial cells, 3-dimensional neural stem cell (NSC)-microglia coculture, and conditioned medium experiments are carried out to comprehend the mechanism underlying the changes in neurogenesis upon redox modulation. RESULTS: In zebrafish, exposure to H2O2 altered embryonic neurogenesis, induced M1 polarization in microglia, and triggered the Wnt/ß-catenin pathway. N9 microglial cell culture experiments revealed that exposure to H2O2 resulted in M1 polarization in microglial cells, and this polarization was mediated by the Wnt/ß-catenin pathway. Redox modulation of microglia interfered with NSC differentiation in coculture experiments. Neuronal differentiation was significantly higher in NSCs cocultured with H2O2-treated microglia when compared to control microglia. Wnt inhibition prevented the effects of H2O2-treated microglia on NSCs. No significant alterations were observed in conditioned medium experiments. CONCLUSIONS: Our findings point to a robust interplay between microglia and neural progenitors influenced by the redox state. Intracellular H2O2 levels can interfere with neurogenesis by altering the phenotypic state of the microglia via the Wnt/ß-catenin system.

Does pendimethalin develop in pancreatic cancer induced inflammation?

Pendimethalin, one of the dinitroaniline group herbicides, is applied for controlling weeds in cereals, legumes and vegetable crops, and has been classified as possible human carcinogen. It is indicated that pendimethalin should arise risks of developing some cancer types; however, there is no data on the effects of pendimethalin on pancreatic cancer-induced inflammation. Injuries resulting from by acute pancreatitis attacks and inflammation are significant factors in the development of pancreatic cancer. Therefore, we investigated whether pendimethalin triggers inflammation as a mechanism of pancreatic cancer development. Parameters related to pancreatic activation, oxidative stress, and inflammation were measured in the human pancreatic (PANC-1) cell line. In the range of 0-100 µM, the levels of chymotrypsin decreased. It should be indicated that the reason for the decrease in chymotrypsin may be the high rates of cell death (20%) observed in the high concentration levels. We observed that pendimethalin significantly induced oxidative damage, while levels of interleukin-6 (IL-6) and interleukin-8 (IL-8) did not change. The obtained results may draw attention to the usage and possible toxic effect of pendimethalin due to oxidative damage induction; however, detailed inflammation mechanisms and other cancer pathways should be investigated.

Polyurethane/hydroxypropyl cellulose electrospun nanofiber mats as potential transdermal drug delivery system: characterization studies and in vitro assays.

Donepezil hydrochloride containing polyurethane/hydroxypropyl cellulose (PU/HPC) nanofibers were prepared by the electrospinning for transdermal drug delivery. PU/HPC nanofibers were characterized with SEM, DSC, and Pascal mercury porosimetry. Drug-excipient interaction was studied by ATR-FTIR. In vitro release of PU/HPC nanofiber mat (10:2:1) exhibited Korsmeyer-Peppas release kinetics controlled by the diffusion of drug. In vitro permeation studies across skin resembling synthetic membrane demonstrated the flux of model drug. The in vitro cytotoxicity data obtained via MTT assay indicated that PU/HPC nanofiber mat could be well tolerated by the skin and the components was not irritant for the skin.

Investigation on the toxic potential of Tribulus terrestris in vitro.

CONTEXT: Tribulus terrestris L. (Zygophyllaceae) has been commonly used to energize, vitalize, and improve sexual function and physical performance in men. OBJECTIVE: This study investigates the potential cytotoxic and genotoxic, and endocrine disrupting activities of T. terrestris in vitro. MATERIALS AND METHODS: The whole T. terrestris plant was extracted with water, methanol, and chloroform. The genotoxic potential of T. terrestris extracts at 3-2400 µg/mL was assessed by Comet assay in a rat kidney cell line (NRK-52E) and by Ames assay in Salmonella typhimurium TA98 and TA100 strains. Endocrine disrupting effects of the extracts at concentrations of 0.22-25 000 µg/mL were assessed by YES/YAS assay in Saccharomyces cerevisiae. Cytotoxic activity of the extracts was determined by the MTT test in NRK-52E cells. The different exposure times were used for four tests (3-48 h). RESULTS: The methanol extract of T. terrestris IC50 value was 160 µg/mL. The other extracts did not show cytotoxic effects. In the Comet and Ames genotoxicity assays, none of the extracts possessed genotoxic activities at concentrations of 0-2400 µg/mL. Only the water extract of T. terrestris induced frame shift mutations after metabolic activation. The water extract also showed estrogenic activity by YES/YAS assay in S. cerevisiae at concentrations ≥27 µg/mL (≥2.6-fold), while the other T. terrestris extracts had anti-estrogenic properties. CONCLUSION: Tribulus terrestris had estrogenic and genotoxic activities. The study was useful in determining its toxicological effects and the precautions regarding consumption.

Effects of bentazone on lipid peroxidation and antioxidant systems in human erythrocytes in vitro.

Bentazone, a benzothiadiazole herbicide, is widely used for a variety of crops including cereals, maize, peas, rice and soy beans. The concern for human health is stil very high because bentazone is continuously monitored in environment and several studies to evaluate its potential carcinogenic effects when chronic and high doses were administered to animals. We aimed to investigate the possible effects of bentazone on lipid peroxidation, levels of glutathione and activities of antioxidant enzymes in human erythrocytes in vitro. For that, erythrocyte were incubated with bentazone in different concentrations (0-50 nM) at 37 °C for 1 hr. Bentazone showed significant increase in the levels of malondialdehyde (MDA) at the highest concentration in erythrocytes as an index of lipid peroxidation. Besides, alterations in the levels of reduced glutathione (GSH) and activities of glutathione peroxidase (GSH-Px) were observed while the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GSH-Rd) were unchanged. In conclusion, findings from this study indicate that in vitro toxicity of bentazone may be associated with oxidative stress and this work warrants further in vivo investigations.

Acute pancreatitis is associated with Ser608Leu iNOS polymorphism.

Acute pancreatitis is an initially localized inflammation of the pancreatic gland. The precise mechanisms by which aetiological factors induce acute pancreatitis are not yet known, but when initiated, common inflammatory pathways seem to be involved, with cytokines being their components of major importance. The inducible nitric oxide synthase gene (iNOS) encodes an enzyme involved in the pathway of reactive oxygen species and induced in response to infection, cytokines. iNOS is capable of generating large quantities of nitric oxide produced during inflammation. The objective of this study was to investigate the association between acute pancreatitis risk and iNOS polymorphisms. The studied single-nucleotide polymorphisms (SNPs) were Ser608Leu, resulting in an amino acid substitution, and 1173C/T and 954G/C, both in the gene promoter region that is linked to increased enzyme expression, leading to higher NO production. The genotypes for the three SNPs were determined in 93 patients with acute pancreatitis and 60 controls without pancreatitis or cancer that were matched for age and gender. Data analysis was done by conditional logistic regression. It was found that the Ser608Leu polymorphism was more frequent among cases with acute pancreatitis compared to controls (OR = 2.88; 95% CI: 1.49-5.57; P = 0.002), although no individually statistically significant associations for the other SNPs studied were detected. We suggest that iNOS Ser608Leu can be used as a marker to define the risk of acute pancreatitis.