Effect of RSN1 gene knockout on the adsorption of strontium ions by irradiated Saccharomyces cerevisiae.

The irradiated Saccharomyces cerevisiae (Y-7) has good biosorption ability for strontium ions. To investigate the mechanism of strontium ion bioaccumulation in Y-7, we employed CRISPR/Cas9 gene editing technology to engineer Saccharomyces cerevisiae Y-7 and knock out the RSN1 gene, successfully constructing a RSN1 gene knockout strain (Y-7-rsn1Δ). When tested for strontium ion adsorption, the Y-7-rsn1Δ strain exhibited decreased capacity for adsorbing strontium ions and increased resistance to strontium ions. The results showed that RSN1 is involved in the transport of Sr2+, and observed significant decreases in intracellular Ca2+ of Y-7-rsn1Δ, indicating a strong correlation between bioaccumulation of Sr2+ and Ca2+. This demonstrated that the adsorption of strontium ions by Y-7 is regulated by the RSN1 gene. The knockout of the RSN1 gene resulted in the shift of the peak positions of carboxyl, amino, amide, hydroxyl, and phosphate groups on the cell surface.

Ferroptosis, a new form of cell death defined after radiation exposure.

PURPOSE: Ferroptosis is an iron-dependent form of regulated cell death, driven by excessive lipid peroxidation and/or inactivation/depletion of protective molecules against lipid peroxidation. Ionizing radiation can induce ferroptosis in both normal tissues and tumor cells. Here, we reviewed the findings of ionizing radiation-induced ferroptosis. CONCLUSIONS: Ionizing radiation induces an increase in hydroxyl radicals, free iron, and lipid metabolic enzymes, which subsequently synergistically initiate a high level of lipid peroxidation, making ionizing radiation an exogenous inducer of ferroptosis. In addition, ferroptosis may be the primary form of cell death in the bone marrow under hematopoietic acute radiation syndrome. Ionizing radiation can also induce changes in iron metabolism, which may be a target for regulating ferroptosis. Finally, ionizing radiation-induced ferroptosis initiates from the cytoplasm and ends on the membrane, and is independent of DNA damage.

Effects of neutron radiation on Nrf2-regulated antioxidant defense systems in rat lens.

Accumulating evidence suggests that ionizing radiation (IR)-induced cataract may be associated with oxidative stress. Nuclear factor erythroid 2-related factor 2 (Nrf2) serves as a master regulator of the antioxidant defense system against oxidative stress. The present study aimed to investigate the effects of different doses of neutron radiation on the Nrf2-reegulated antioxidant defense system in rat lens and assess the status of oxidative stress. A total of 24 SD rats were randomly divided into the following four groups: i) Control group; iis) 0.4 Sv group; iii) 1.2 Sv group; and iv) 3.6 Sv group. The rats were sacrificed 7 days after radiation and lenses were dissected for histological, biochemical (malondialdehyde, glutathione and superoxide dismutase) and western blot (Nrf2, glutamate-cysteine ligase catalytic subunit and heme oxygenase 1) analyses. The morphological features of the lenses remained intact in the 0.4 Sv, 1.2 Sv and control groups, whilst the lenses in the 3.6 Sv group exhibited injuries. Results from the TUNEL assay demonstrated apparent apoptosis in lens epithelial cells following 3.6 Sv neutron radiation whereas sparse apoptosis was observed following 0.4 Sv and 1.2 Sv radiation. Malondialdehyde levels were reduced in the 0.4 Sv and 1.2 Sv groups but increased in the 3.6 Sv group, compared with those in the control group. Conversely, glutathione expression and the activity of superoxide dismutase were higher in the 0.4 Sv and 1.2 Sv groups, but lower in the 3.6 Sv group, compared with those in the control group. In addition, the total and nuclear protein levels of Nrf2 were increased following neutron radiation compared with those in the control group, though the Nrf2 protein levels decreased in the 3.6 Sv group compared with those in the 1.2 Sv group. The levels of glutamate-cysteine ligase catalytic subunit and heme oxygenase 1, downstream antioxidant enzymes of Nrf2, demonstrated the same profile as that in Nrf2. Taken together, the results of the present study suggest that neutron radiation affects Nrf2-regulated antioxidant systems in a two-stage process. Namely, the induction phase for low-dose radiation and regression phase for high-dose radiation. Therefore, it was hypothesized that activation and enhancement of the Nrf2-regulated antioxidant system may be useful in preventing or delaying IR-induced cataract, which may be extended even for other diseases associated with oxidative stress.

Hematopoietic protection and mechanisms of ferrostatin-1 on hematopoietic acute radiation syndrome of mice.

PURPOSE: Baicalein (an anti-ferroptosis drug) was recently reported to synergistically improve the survival rate of mice following a high dose of total body irradiation with anti-apoptosis and anti-necroptosis drugs. At the same time, our group has demonstrated that ferrostatin-1, a ferroptosis inhibitor, improves the survival rate of a mouse model of hematopoietic acute radiation syndrome to 60% for 150 days (p < .001). These phenomena suggest that ferroptosis inhibition can mitigate radiation damage. In this study, we continued to study the mechanisms by which ferrostatin-1 alleviated radiation-induced ferroptosis and subsequent hematopoietic acute radiation syndrome. MATERIALS AND METHODS: Male ICR mice (8-10 weeks old) were exposed to doses of 0, 8, or 10 Gy irradiated from a 137Cs source. Ferrostatin-1 was intraperitoneally injected into mice 72 h post-irradiation. Bone marrow mononuclear cells (BMMCs) and peripheral blood cells were counted. The changes in iron-related parameters, lipid metabolic enzymes, lipid peroxidation repair molecules (glutathione peroxidase 4, glutathione, and coenzyme Q10), and inflammatory factors (TNF-α, IL-6, and IL-1ß) were evaluated using biochemical or antibody techniques. RESULTS: Ferrostatin-1 increased the number of red and white blood cells, lymphocytes, and monocytes in the peripheral blood after total body irradiation in mice by mitigating the ferroptosis of BMMCs. Total body irradiation induced ferroptosis in BMMCs by increasing the iron and lipid peroxidation levels and depleting the acyl-CoA synthetase long-chain family member 4 (ASCL4), lipoxygenase 15, glutathione peroxidase 4, and glutathione levels. Ferroptotic BMMCs did not release TNF-α, IL-6, or IL-1ß at the early stage of radiation exposure. Ferrostatin-1 mitigated the lipid peroxidation of radiation-induced ferroptosis by attenuating increases in levels of hemosiderin and liable iron pool and decreases in levels of ASCL4 and glutathione peroxidase 4. CONCLUSIONS: The onset of total body irradiation-induced ferroptosis in BMMCs involved changes in iron, lipid metabolic enzymes, and anti-lipid peroxidation molecules. Ferrostatin-1 could be a potential radiation mitigation agent by acting on these targets.

Core-Shell Molecularly Imprinted Polymers on Magnetic Yeast for the Removal of Sulfamethoxazole from Water.

In this work, magnetic yeast (MY) was produced through an in situ one-step method. Then, MY was used as the core and the antibiotic sulfamethoxazole (SMX) as the template to produce highly selective magnetic yeast-molecularly imprinted polymers (MY@MIPs). The physicochemical properties of MY@MIPs were assessed by Fourier-transform infrared spectroscopy (FT-IR), a vibrating sample magnetometer (VSM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), specific surface area (SBET) determination, and scanning electron microscopy (SEM). Batch adsorption experiments were carried out to compare MY@MIPs with MY and MY@NIPs (magnetic yeast-molecularly imprinted polymers without template), with MY@MIPs showing a better performance in the removal of SMX from water. Adsorption of SMX onto MY@MIPs was described by the pseudo-second-order kinetic model and the Langmuir isotherm, with maximum adsorption capacities of 77 and 24 mg g-1 from ultrapure and wastewater, respectively. Furthermore, MY@MIPs displayed a highly selective adsorption toward SMX in the presence of other pharmaceuticals, namely diclofenac (DCF) and carbamazepine (CBZ). Finally, regeneration experiments showed that SMX adsorption decreased 21 and 34% after the first and second regeneration cycles, respectively. This work demonstrates that MY@MIPs are promising sorbent materials for the selective removal of SMX from wastewater.

Ionizing radiation induces ferroptosis in granulocyte-macrophage hematopoietic progenitor cells of murine bone marrow.

Purpose: To study whether radiation-induced bleeding in the bone marrow induced iron accumulation, and subsequently caused ferroptosis in granulocyte-macrophage hematopoietic progenitor cells.Materials and methods: Male mice were subjected to different doses (0, 4, 8, or 10 Gy) of gamma radiation from a 137Cs source. The changes in iron metabolism or ferroptosis-related parameters of irradiated bone marrow were accessed with biochemical, histopathological, and antibody methods. Hematocytes were detected with a hematology analyzer. The counts of granulocyte-macrophage hematopoietic progenitor cells were measured with the granulocyte-macrophage colony-forming unit.Results: Iron accumulation occurred in the bone marrow, which caused by radiation-induced hemorrhage. The iron accumulation triggered an iron regulatory protein-ferroportin 1 axis to increase serum iron levels. Using LDN193189, radiation-induced iron accumulation was demonstrated to decrease white blood cell counts at least partly through a decrease in the counts of granulocyte-macrophage hematopoietic progenitor cells. The reduction in the counts of granulocyte-macrophage hematopoietic progenitor cells was subsequently demonstrated to attribute to ferroptosis with the use of ferroptosis inhibitors and through the detection of ferroptosis related-parameters. The survival rate of irradiated mice was improved using Ferrostatin-1 or LDN193189.Conclusions: These findings suggest that radiation-induced hemorrhage in the bone marrow causes ferroptosis in granulocyte-macrophage hematopoietic progenitor cells, and anti-ferroptosis has the potential to be a radioprotective strategy to ameliorate radiation-induced hematopoietic injury.

Mechanisms of strontium's adsorption by Saccharomyces cerevisiae: Contribution of surface and intracellular uptakes.

The objective of this work was to explore the mechanisms participating in strontium sorption by living Saccharomyces cerevisiae (S. cerevisiae). The location of strontium adsorbed by S. cerevisiae was studied by our plasmolysis treatment. The contribution of physical and chemical mechanisms was determined quantitatively by desorption and blockage of functional groups. Moreover, our results indicated that bioaccumulation also played a major role in biosorption by living cells. Thus, supplementary methods including 2-DE (two-dimensional electrophoresis) and Matrix-Assisted Laser Desorption/Ionization Tandem Time of Flight Mass Spectrometry (MALDI-TOF-TOF) were employed to analyze the different proteins. The subsequent desorption % of Sr2+ by Distilled Water (DW), NH4NO3 and EDTA-Na2 from Sr2+ loaded sorbents indicated a minor role for physical adsorption, while ion exchange and complexation were responsible for approximately 20% and 40%. Specific blockage of functional groups revealed that carboxyl and amine groups played an important role in Sr2+ binding to the living S. cerevisiae. From our MALDI-TOF-TOF results, we concluded that 38 proteins showed up-regulated expression profiles and 11 proteins showed down-regulated after biosorption. Moreover, proteins belong to: phagocytic function (Act1p); ion channel (S-adenosylmethionine synthase); glycolysis (Tubulin) may directly involve in strontium bioaccumulation. In conclusion, the present work indicates that the strontium sorption mechanism by living S. cerevisiae is complicated including ion-exchange along with complexation as the main mechanism, whereas the other mechanisms such as physical adsorption play a minor contribution. Metabolically-dependent proteins may play an important role in bioaccumulation.

Biosorption of strontium ions from simulated high-level liquid waste by living Saccharomyces cerevisiae.

In this study, the Saccharomyces cerevisiae (S. cerevisiae) was modified by γ-ray. The RNA-seq results reflect that the high γ-ray energies could change some gene fragments, such as deletion, recombination, and mutation. The biosorption of strontium ions (Sr2+) to different types of S. cerevisiae (S. cerevisiae (K-0), modified S. cerevisiae (Y-7), and non-living S. cerevisiae (H-K)) from the simulated high-level liquid waste (S-HLLW) was assessed at different experimental conditions. The sorption experimental results show that, under an appropriate condition, γ-ray radiation can enhance its biosorption capacity slightly of Sr2+ to S. cerevisiae. The maximum metal uptake and efficiency of Y-7 under S-HLLW were 11.656 mg g-1 and 37.91% at 32 h (wet weight), respectively. They decreased to 9.46 mg g-1 and 30.76% under radiation conditions. SEM-EDX and TEM analysis indicates that Sr2+ was adsorbed both on the cellular surface and the inner parts of the cells. Our experimental results fit well to the Langmuir and Freundlich model isotherms (r2 > 0.94), and the maximum biosorption capacity values reached qmax > 24.74 mg g-1 at 32 °C. Negative values of ΔG0 and positive values of ΔH0 were observed, indicating the spontaneous and endothermic nature of Sr2+ biosorption on modified S. cerevisiae. The biosorption kinetics follow a pseudo-second-order equation at 32 °C (r2 > 0.94). The desorption efficiency of Sr2+ adsorbed onto Y-7 was 7.65 ± 0.52%, 76.51 ± 2.13%, and 65.62 ± 2.42% by deionized water, 1 M HCl, and 0.1 M EDTA-Na, respectively. However, they were lower than H-K (18.82, 83.32, and 73.32%). Our findings demonstrate that living S. cerevisiae (Y-7) is a promising sorbent material for the treatment of radioactive process streams.

Radiosensitivity enhancement of Fe3O4@Ag nanoparticles on human glioblastoma cells.

Radiotherapy is one of the main therapeutic methods for cancers, but radiation resistance of cancer cells still remains a serious concern. Searching for radiosensitizers to overcome such resistance is therefore urgently required. The goal of this study is to evaluate and compare the radiosensitizing efficacy of Fe3O4-OA, Ag and Fe3O4@Ag nanoparticles on U251 cells. The results show that Fe3O4@Ag nanoparticles have the highest ability of radiosensitization among the three nanoparticles. The underlying mechanism of Fe3O4@Ag nanoparticles' radiosensitivity enhancement is through decrease of the cytoprotective autophagy at the early stage, and increase of the calcium-dependent apoptosis at the later stage. These findings suggest the potential application of Fe3O4@Ag nanoparticles as a highly effective nano-radiosensitizer for the treatment of glioblastoma cells.

Biosorption of the strontium ion by irradiated Saccharomyces cerevisiae under culture conditions.

As a new-emerging method for strontium disposal, biosorption has shown advantages such as high sorption capacity; low cost. In this study, we investigated the potential of Saccharomyces cerevisiae (S. cerevisiae) in strontium disposal under culture conditions and the effects of irradiation on their biosorption capabilities. We found that S. cerevisiae can survive irradiation and grow. Pre-exposure to irradiation rendered S. cerevisiae resistant to further irradiation. Surprisingly, the pre-exposure to irradiation can increase the biosorption capability of S. cerevisiae. We further investigated the factors that influenced the biosorption efficiency, which were (strongest to weakest): pH > strontium concentration > time > temperature. In our orthogonal experiment, the optimal conditions for strontium biosorption by irradiated S. cerevisiae were: pH 7, 150 mg L-1 strontium at the temperature of 32 °C with 30 h. The equilibrium of strontium biosorption was analyzed by Langmuir and Freundlich models, from which the formal model is found to provide a better fit for the experimental results. The kinetics of strontium biosorption by living irradiated S. cerevisiae was found to be comprised of three phases: dramatically increased during 0-9 h, decreased during 12-24 h, and increased during 30-50 h. These results provide a systematic understanding of the biosorption capabilities of irradiated S. cerevisiae, which can contribute to the development of remediating nuclear waste water.

Inhibitory effect of endostar on specific angiogenesis induced by human hepatocellular carcinoma.

To investigate the effect of endostar on specific angiogenesis induced by human hepatocellular carcinoma, this research systematically elucidated the inhibitory effect on HepG2-induced angiogenesis by endostar from 50 ng/mL to 50000 ng/mL. We employed fluorescence quantitative Boyden chamber analysis, wound-healing assay, flow cytometry examination using a coculture system, quantitative analysis of tube formation, and in vivo Matrigel plug assay induced by HCC conditioned media (HCM) and HepG2 compared with normal hepatocyte conditioned media (NCM) and L02. Then, we found that endostar as a tumor angiogenesis inhibitor could potently inhibit human umbilical vein endothelial cell (HUVEC) migration in response to HCM after four- to six-hour action, inhibit HCM-induced HUVEC migration to the lesion part in a dose-dependent manner between 50 ng/mL and 5000 ng/mL at 24 hours, and reduce HUVEC proliferation in a dose-dependent fashion. Endostar inhibited HepG2-induced tube formation of HUVECs which peaked at 50 ng/mL. In vivo Matrigel plug formation was also significantly reduced by endostar in HepG2 inducing system rather than in L02 inducing system. It could be concluded that, at cell level, endostar inhibited the angiogenesis-related biological behaviors of HUVEC in response to HCC, including migration, adhesion proliferation, and tube formation. At animal level, endostar inhibited the angiogenesis in response to HCC in Matrigel matrix.

[Effects of tetramethylpyrazine on expression of vascular endothelial growth factor and hypoxia-induced factor-1alpha by rat peritoneal macrophages].

OBJECTIVE: To investigate the effects of tetramethylpyrazine on lipopolysaccharides (LPS)-induced expression of vascular endothelial growth factor (VEGF) and hypoxia-induced factor-1alpha (HIF-1alpha) in macrophages. METHOD: Rat peritoneal macrophages were treated with LPS, and at the same time given different doses of tetramethylpyrazine. The secreation of VEGF was determined by ELISA test, and MTT assay was used to examine cells proliferation. Western blot assay was used to examine the expression of HIF-1alpha. RESULT: 100 microg x mL(-1) and 10 microg x mL(-1) tetramethylpyrazine decreased the secretion of VEGF and also inhibited the expression of HIF-1alpha by LPS-induced macrophages. But these doses of tetramethylpyrazine had no effect on the cells proliferation. CONCLUSION: Tetramethylpyrazine could inhibit the secretion of VEGF by LPS-induced macrophages, and the mechanism must be associated with inhibiting the expression of HIF-1alpha. The inhibition effect was not due to inhibition of the proliferation of macrophages.

[Tumor multidrug-resistance and reversing actions of traditional Chinese medicine].

Tumor multidrug-resistance (MDR) is a major factor in chemotherapeutic failure. In recent years, the development of anti-MDR has become an important focus in research. The mechanisms of MDR relate to P-glycoprotein, MRP1, apoptosis, the unusual DNA repair, the organic micro-environment, and so on. This review summarized the advances in MDR mechanism research. At the same time, it summarized the recent research of traditional Chinese medicine in reversing MDR. Furthermore, their mechanisms and major features of actions were also discussed.