Staphylococcal enterotoxin B exposed to pregnant rats inhibits the hedgehog signaling pathway in thymic T lymphocytes of the offspring.

The Hedgehog (Hh) signaling pathway is involved in T cell differentiation and development and plays a major regulatory part in different stages of T cell development. A previous study by us suggested that prenatal exposure to staphylococcal enterotoxin B (SEB) changed the percentages of T cell subpopulation in the offspring thymus. However, it is unclear whether prenatal SEB exposure impacts the Hh signaling pathway in thymic T cells. In the present study, pregnant rats at gestational day 16 were intravenously injected once with 15 µg SEB, and the thymi of both neonatal and adult offspring rats were aseptically acquired to scrutinize the effects of SEB on the Hh signaling pathway. It firstly found that prenatal SEB exposure clearly caused the increased expression of Shh and Dhh ligands of the Hh signaling pathway in thymus tissue of both neonatal and adult offspring rats, but significantly decreased the expression levels of membrane receptors of Ptch1 and Smo, transcription factor Gli1, as well as target genes of CyclinD1, C-myc, and N-myc in Hh signaling pathway of thymic T cells. These data suggest that prenatal SEB exposure inhibits the Hh signaling pathway in thymic T lymphocytes of the neonatal offspring, and this effect can be maintained in adult offspring via the imprinting effect.

Prenatal Exposure of Rats to Staphylococcal Enterotoxin B Alters the Expression of Th1 and Th2 Cytokines via Decreased Methylation in the Spleen of Adult but not Neonatal Offspring.

BACKGROUND: The methylation of IFN-γ and IL-4 genes is regarded as an epigenetic regulation that maintains the Th1 or Th2 phenotype. OBJECTIVE: To explore the influence of prenatal administration of the staphylococcal enterotoxin B (SEB) in pregnant rats, on the IFN-γ or IL-4 expression in the offspring spleen. METHODS: The SEB or PBS was administered intravenously to pregnant rats on the embryo-day 16. After normal delivery, the spleens from the fifth-day neonates and adult offspring were isolated under anesthesia. Quantitative PCR, western blot, ELISA and MeDIP-qPCR were applied to determine the levels of the splenic IFN-γ or IL-4 mRNAs, their protein levels, and methylation status, respectively. RESULTS: Prenatal administration of the SEB in pregnant rats decreased the levels of the splenic IFN-γ and IL-4 proteins in neonates, but increased their mRNA levels. However, prenatal administration of the SEB significantly augmented both mRNA and protein levels of the IFN-γ and IL-4 in the adult spleen. In addition, the prenatal SEB administration decreased the methylation of the splenic IFN-γ and IL-4 in adult but not neonatal offspring. CONCLUSION: The prenatal administration of SEB in pregnant rats can cause a mixed Th1 and Th2 cytokines response in the offspring spleen, and alter the cytokine expression of the Th1 and Th2 via decreasing the methylation in adult but, not neonatal offspring spleen.

Molecular insight into the variation of dissolved organic phosphorus in a wastewater treatment plant.

To date, eutrophication becomes a great concern of vulnerable aquatic systems. Dissolved organic phosphorus (DOP) discharged from wastewater treatment plant (WWTP) holds a large source of phosphorus in receiving water. However, due to the complexity of DOP, their variation and fate in WWTP remain unknown at the molecular level, and are always overlooked. Here, the variation of DOP in a WWTP was uncovered via Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). Results show that 95% of DOP in the influent could be removed by the secondary biological treatment processes. The removed DOP species were mainly lipids with the molecular characteristics of low oxygen content, low unsaturation and low aromaticity. Meanwhile, during biological treatments, some new DOP species, especially lignin/carboxylic rich alicyclic molecules (CRAM) that possessed high oxygen content, high unsaturation and high aromaticity, were produced and released into the secondary effluent. In the subsequent tertiary treatment, coagulation by aluminum salt tended to remove high molecular weight and high oxygen content DOP species in the secondary effluent, which was complementary to the biological treatment. However, the sand filter usually retained microorganisms, which would result in the generation of new DOP species in this process. During the final ultraviolet disinfection process, DOP was effectively mineralized to phosphate, especially the species with high molecular weight and highly unsaturated aromatic DOP species (e.g., lignin/CRAM and tannin), which had higher UV absorbance. The revealed variation of DOP in WWTP is beneficial to optimize the treatment processes to enhance the removal of DOP.

Exposure of pregnant rats to staphylococcal enterotoxin B increases offspring splenic Treg number and function via decreasing FoxP3 methylation.

Staphylococcus aureus is an infectious pathogen that is relatively common, but that can cause severe disease in pregnant women and their fetus. We previously demonstrated that exposing pregnant rats to staphylococcal enterotoxin B (SEB) altered splenic CD4/CD8 T cell frequencies in their offspring. Whether prenatal SEB exposure impacts Tregs in these offspring, however, remains to be determined. As such, in this study, we intravenously injected pregnant rats with 15 µg of SEB on gestational day 16. Splenic tissue was then harvested from 1-, 3-, and 5-day-old neonatal rats and analyzed via flow cytometry to assess Treg numbers. In addition, FoxP3 expression levels were assessed via qPCR and western blotting, while FoxP3 methylation status was evaluated via methyl-DNA immunoprecipitation qPCR. Immunosuppression assays were additionally used to gauge Treg suppressive functionality. We found that exposing pregnant rats to SEB resulted in a significant increase in Treg numbers, FoxP3 expression, and Treg suppressive capacity in the spleens of both neonatal and adult offspring. In addition, total T cell, CD4+T cell, and non-Treg CD4+ T cell numbers were elevated in the spleens of offspring following prenatal SEB exposure. We additionally determined that SEB exposure resulted in a significant reduction in FoxP3 DNA methylation. Together, our results indicate that prenatal SEB exposure can markedly enhance offspring splenic Treg numbers and functionality at least in part by decreasing FoxP3 methylation.

Exposure of pregnant rats to staphylococcal enterotoxin B attenuates the response of increased Tregs to re-exposure to SEB in the thymus of adult offspring.

Regulatory T cells (Tregs) play an essential role during homeostasis and tolerance of the immune system. Based on our previous study that exposure of pregnant rats to staphylococcal enterotoxin B (SEB) can alter the percentage of CD4/CD8 subsets in the thymus of the offspring, in this study, we focus on the influence of exposure of pregnant rats to SEB on number, function and response of Tregs in the thymus of the offspring. Pregnant rats at gestational day of 16 were intravenously injected with 15 µg SEB and the thymuses of the neonatal and adult offspring were harvested for this study. We found that exposure of pregnant rats to SEB could significantly increase the absolute number of Tregs and the FoxP3 expression level in the thymus of not only neonatal but also adult offspring. Re-exposure of adult offspring to SEB remarkably reduced the suppressive capacity of Tregs to CD4+ T cells and the expression levels of TGF-ß and IL-10 in the thymus, but had no effect on production of IL-4 and IFN-γ. Furthermore, it also notedly decreased the absolute number of Tregs and the FoxP3 expression level. These data suggest that prenatal exposure of pregnant rats to SEB attenuates the response of increased Tregs to re-exposure to SEB in the thymus of adult offspring.

Prenatal exposure of staphylococcal enterotoxin B attenuates the development and function of blood regulatory T cells to repeated staphylococcal enterotoxin B exposure in adult offspring rats.

Introduction. Staphylococcal enterotoxin B (SEB) is an extensively studied super-antigen. A previous study by us suggested that SEB exposure during pregnancy could alter the percentage of CD4+ and CD8+ T cells in the peripheral blood of neonatal offspring rats.Aim. It is unknown whether SEB exposure during pregnancy can influence the development of regulatory T cells (Tregs) in the peripheral blood of neonatal offspring rats.Methodology. Pregnant rats at gestational day 16 were intravenously injected with 15 µg SEB. Peripheral blood was acquired from neonatal offspring rats on days 1, 3 and 5 after delivery and from adult offspring rats for determination of Treg number by cytometry, cytokines by ELISA, and FoxP3 expression by real-time PCR and western blot.Results. SEB given to pregnant rats significantly increased the absolute number of Tregs and the expression levels of FoxP3, IL-10 and TGF-ß (P<0.05, P<0.01) in the peripheral blood of not only neonatal but also adult offspring rats. Furthermore, repeated SEB exposure in adult offspring rats significantly decreased the absolute number of Tregs (P<0.01), and the expression levels of FoxP3, IL-10 and TGF-ß (P<0.05, P<0.01) in their peripheral blood.Conclusion. Prenatal SEB exposure attenuates the development and function of Tregs to repeated SEB exposure in the peripheral blood of adult offspring rats.

Mitigated membrane fouling and enhanced removal of extracellular antibiotic resistance genes from wastewater effluent via an integrated pre-coagulation and microfiltration process.

Antibiotic resistance genes (ARGs) have been regarded as an emerging pollutant in municipal wastewater treatment plant (WWTP) effluents due to their potential risk to human health and ecological safety when reused for landscape and irrigation. Conventional wastewater treatment processes generally fail to effectively reduce ARGs, especially extracellular ARGs (eARGs), which are persistent in the environment and play an important role in horizontal gene transfer via transformation. Herein, an integrated process of pre-coagulation and microfiltration was developed for removal of ARGs, especially eARGs, from wastewater effluent. Results show that the integrated process could effectively reduce the absolute abundances of total ARGs (tARGs) (>2.9 logs) and eARGs (>5.2 logs) from the effluent. The excellent performance could be mainly attributed to the capture of antibiotic resistant bacteria (ARB) and eARGs by pre-coagulation and co-rejection during subsequent microfiltration. Moreover, the integrated process exhibited a good performance on removing common pollutants (e.g., dissolved organic carbon and phosphate) from the effluent to improve water quality. Besides, the integrated process also greatly reduced membrane fouling compared with microfiltration. These findings suggest that the integrated process of pre-coagulation and microfiltration is a promising advanced wastewater treatment technology for ARGs (especially eARGs) removal from WWTP effluents to ensure water reuse security.

[Effect of cordycepin on apoptosis and autophagy of tongue cancer cells in vitro and the molecular mechanism].

OBJECTIVE: To study the effect of cordycepin on cell cycle, apoptosis and autophagy of human tongue cancer TCA-8113 cells and explore the mechanism of cordycepin for inhibiting the occurrence of tongue cancer. METHODS: CCK-8 method was used to assess the inhibitory effect of cordycepin on TCA-8113 cell proliferation in vitro. The cell cycle and cell apoptosis of TCA-8113 cells treated with different concentrations of cordycepin were analyzed using flow cytometry. The expressions of apoptosis-related genes caspase-3, caspase-9, Bcl-2, and Bax were examined using quantitative real-time PCR and Western blotting, and immunohistochemistry was used to detect the expressions of autophagy-related proteins LC-3ß, P62, p-mTOR, and AMPK. RESULTS: CCK-8 assay showed that cordycepin significantly inhibited the proliferation of TCA-8113 cells in a concentration-dependent manner with an IC50 of 3.548 mg/mL at 24 h and an IC50 of 1.185 mg/mL at 48 h. Flow cytometric analysis showed that cordycepin caused cell cycle arrest at S phase and dose-dependently increased the apoptotic rate of TCA-8113 cells. Treatment of the cells with cordycepin enhanced the expressions of Bax, caspase-3 and caspase-9 at both the mRNA and protein levels and inhibited the expression of the antiapoptotic gene Bcl-2. Immunohistochemistry demonstrated that cordycepin promoted the expression of LC-3ß and AMPK and inhibited the expression of P62 and p-mTOR. CONCLUSION: Cordycepin inhibits the proliferation and induces apoptosis of HCT-116 cells through the mitochondrial pathway and induces autophagy via the AMPK/mTOR pathway.

Staphylococcal enterotoxin B administration in pregnant rats alters the splenic lymphocyte response in adult offspring rats.

BACKGROUND: Our previous study suggested that SEB exposure in pregnant rats could lead to the change of T cells subpopulation in both peripheral blood and thymus of the offspring rats. However, rarely is known about the influence of SEB exposure in pregnant rats on T cell subpopulation in the spleens of offspring rats. RESULTS: SEB was intravenously administered to the pregnant rats at gestational day 16 in this study. The percentages, in vivo and in vitro responses of CD4 and CD8 T cells were investigated with flow cytometry. The prenatal SEB exposure obviously increased splenic CD4 T cell percentages of both neonates and adult offspring rats, and obviously reduced splenic CD8 T cell percentages of both the fifth day neonates and adult offspring rats. After spleens in the adult offspring rats were re-stimulated with SEB in vivo or in vitro, in vivo SEB stimulation could lead to the marked decrease of splenic CD4 T cell percentage and the marked increase of splenic CD8 T cell percentage. While in vitro SEB stimulation to the cultured splenocytes markedly decreased the proliferation of the splenic lymphocytes and the CD4 T cell percentage, and had no influence on CD8 T cell percentage. CONCLUSION: The prenatal SEB exposure could alter the percentages of CD4/CD8 T cell subpopulation and the response of CD4 and CD8 T cells to the in vivo and in vitro secondary SEB stimulation in the splenocytes of adult offspring rats.