Free Radical Research最新文献

During the synthesis of a known drug, we synthesized a novel compound impromptu, which we have named resorcimoline. This compound exhibited significant antioxidative activity. In this report, we present the concentration-dependent free radical scavenging activity of resorcimoline against various free radical species. The scavenging activity of resorcimoline was evaluated against nine free radicals using electron spin resonance spectroscopy with a spin-trapping method. These free radicals were hydroxyl radical, superoxide anion, tert-butyl peroxyl radical, tert-butoxyl radical, ascorbyl free radical, singlet oxygen, nitric oxide, 2,2-diphenyl-1-picrylhydrazyl, and tyrosyl radical. Sigmoid concentration-response curves were fitted to estimate the reaction rate constants of resorcimoline for the free radicals, and these were compared with those of edaravone, the only current clinically approved free radical scavenger. The antioxidative activity of resorcimoline against lipid peroxidation within tissue was assessed using the thiobarbituric acid reactive substance (TBARS) assay. The cytotoxicity and stability of resorcimoline were also evaluated. Resorcimoline demonstrated significant concentration-dependent scavenging activity against all tested free radicals. Notably, the reaction rate constants for superoxide anion and nitric oxide were significantly higher than those of edaravone, while the rate constant for hydroxyl radical was significantly lower. The TBARS assay revealed that resorcimoline inhibited tissue lipid peroxidation in a concentration-dependent manner. Moreover, resorcimoline exhibited no cytotoxicity at concentrations up to 100 μM and remained stable at room temperature under ambient light for 7 d. These findings indicate that resorcimoline's direct free radical scavenging activity could contribute to its potential clinical antioxidative effects.

Background: Acute myocardial infarction (AMI) is a deadly cardiovascular disease with no effective solution except for percutaneous coronary intervention and coronary artery bypass grafting. Inflammation and apoptosis of the injured myocardium after revascularization seriously affect the prognosis. Hydrogen possesses anti-inflammatory, anti-oxidative, and anti-apoptotic effects and may become a new treatment for AMI. This study explored the specific mechanism by which hydrogen operates during AMI treatment.

Methods: Thirty Sprague-Dawley rats were randomly divided into three groups: control, myocardial infarction (MI), and myocardial infarction + hydrogen (MI+H₂), each containing 10 rats. The MI rat model was established by ligation of the left anterior descending branch. The MI+H₂ group received 2% hydrogen inhalation treatment for 3 h/Bid.

Results: Myocardial infarct size was evaluated using triphenyl tetrazolium chloride staining. Transmission electron microscopy showed reduced mitochondrial damage compared with the MI group. JC-1 staining, which indicates mitochondrial membrane potential, showed a low red/green fluorescence intensity ratio in the MI group compared to that in the control group, indicating mitochondrial membrane potential loss. After hydrogen inhalation, this ratio increased, suggesting partial recovery of membrane potential. In addition, mitochondrial ATP content, mitochondrial complex I, and mitochondrial complex III activity were significantly decreased in the MI group, which was improved after hydrogen administration. Western blotting analysis showed decreased Cyt-c protein levels in the myocardial mitochondria and increased levels in the cytoplasm of MI rats. Following hydrogen inhalation, the levels of ROS, 8-OHdG, and MDA that could represent oxidative stress injury significantly decreased. Besides, the expression of Cyt-C, Bax, cleaved-caspase-9, and cleaved-caspase-3 in MI group significantly increased, while the Bcl-2, TRX2, SOD2 expression decreased. The expression of these proteins in MI+H2 group was improved compared with the MI group.

Conclusion: Overall, hydrogen inhalation reduces myocardial infarct size, improves mitochondrial dysfunction, and modulates the levels of apoptosis-related substances. Importantly, Hydrogen reduces acute myocardial infarction damage by downregulating ROS and upregulating antioxidant proteins.

Methotrexate (MTX) is a well-known anti-metabolite agent recognized for its oxidative effects, particularly in the liver where the enzyme catalase is abundant. This research aimed to clarify the impact of MTX on the behavior of liver catalase. The cytotoxicity of HepG2 cells was assessed across various concentrations of MTX. Following that, the examination focused on the generation of reactive oxygen species (ROS) and the activity of catalase. Furthermore, the kinetic activity of bovine liver catalase (BLC) was examined in the presence of MTX. Finally, the interaction between MTX and the enzyme's protein structure was investigated using docking and dynamic light scattering (DLS) methods. The results indicated a significant decrease in catalase activity and a significant increase in ROS production in HepG2 cells treated with MTX. Although the activity of BLC remained unaffected by MTX directly, molecular docking and DLS techniques revealed MTX binding to BLC, inhibiting its tetramerization. The oxidative effects of MTX were associated with elevated ROS levels in cellular processes, leading to excessive catalase activity and subsequent suicide inactivation. Furthermore, MTX influenced the protein structure of catalase.

Inflammatory bowel diseases (IBD), which include Crohn's disease and ulcerative colitis, represent a global health issue as a prevalence of 1% is expected in the western world by the end of this decade. These diseases are associated with a high oxidative stress that induces inflammatory pathways and severely damages gut tissues. IBD patients suffer from antioxidant defenses weakening, through, for instance, an impaired activity of superoxide dismutases (SOD)-that catalyze the dismutation of superoxide-or other endogenous antioxidant enzymes including catalase and glutathione peroxidase. Manganese complexes mimicking SOD activity have shown beneficial effects on cells and murine models of IBD. However, efficient SOD mimics are often manganese complexes that can suffer from decoordination and thus inactivation in acidic stomachal pH. To improve their delivery in the gut after oral administration, two SOD mimics Mn1 and Mn1C were loaded into lactic acid bacteria that serve as delivery vectors. When orally administrated to mice suffering from a colitis, these chemically modified bacteria (CMB) showed protective effects on the global health status of mice. In addition, they have shown beneficial effects on lipocalin-2 content and intestinal permeability. Interestingly, mRNA SOD2 content in colon homogenates was significantly decreased upon mice feeding with CMB loaded with Mn1C, suggesting that the beneficial effects observed may be due to the release of the SOD mimic in the gut that complement for this enzyme. These CMB represent new efficient chemically modified antioxidant probiotics for IBD treatment.

Hepatocellular carcinoma (HCC) is a common and deadly form of liver cancer with limited treatment options for advanced stages. Mesoionic compounds MI-D and MI-J have shown potential for treating HCC due to their significant toxicity to these cells. This study investigated whether this toxicity is linked to their effects on oxidative balance in HepG2 cells cultured in high glucose (HG-glycolysis-dependent) and galactose plus glutamine supplemented (GAL-oxidative phosphorylation-dependent) DMEM medium. ROS levels were increased in cells cultured in both media when exposed to MI-D and MI-J (50 μM). However, MI-D at an intermediate concentration (25 μM) decreased ROS levels in the GAL medium. Superoxide dismutase (SOD) activity increased under all tested conditions by compounds (25 μM). Conversely, MI-D and MI-J decreased total peroxidase activity in both media at 25 and 50 μM, respectively. MI-D in the HG medium decreased glutathione peroxidase (GPX) activity, whereas MI-J reduced the enzyme activity at a concentration of 25 μM and increased it at 50 μM. In the GAL medium, MI-J (50 μM) increased GPx activity, while glutathione reductase (GR) activity was decreased by the compounds (50 μM) in both media. Furthermore, the P-AMPK/tAMPk ratio was increased by MI-J at 25 μM in the GAL medium. Our results show that MI-D and MI-J caused oxidative imbalance, particularly affecting cells cultured in the GAL medium. The data also support that the mesoionic effects depended on their concentration and substituent in the mesoionic ring.

Skeletal muscle satellite cells (SMSCs) are pivotal for skeletal muscle regeneration post-injury, and their development is intricately influenced by regulatory factors. Selenoprotein K (SELENOK), an endoplasmic reticulum resident selenoprotein, is known for its crucial role in maintaining skeletal muscle redox sensing. However, the specific molecular mechanism of SELENOK in SMSCs remains unclear. In this study, a SELENOK knockdown model was established to delve into its role in SMSCs. The results revealed that SELENOK knockdown hindered SMSCs proliferation and differentiation, as evidenced by the regulation of key proteins such as Pax7, Myf5, CyclinD1, MyoD, and Myf6, and the inhibitory effects were mitigated by N-Acetyl-l-cysteine (NAC). SELENOK knockdown induced oxidative stress, further analyses uncovered that SELENOK knockdown downregulated nuclear transcription factor nuclear erythroid factor 2-like 2 (Nrf2) protein expression while upregulating cytoplasmic kelch-like ECH-associated protein 1 (Keap1) protein expression. SELENOK knockdown impeded Nestin and sequestosome 1/p62 (p62) interaction with Keap1, leading to increased Nrf2 ubiquitination. This prevented Nrf2 transportation from cytoplasm to nucleus mediated by Keap1, ultimately resulting in the downregulation of catalase (CAT), heme oxygenase-1 (HO-1), and glutathione peroxidase 4 (GPX4) protein expression. Notably, SELENOK knockdown-induced inhibition of SMSCs proliferation and differentiation was alleviated by Oltipraz, an activator of the Nrf2 pathway. This study provided novel insights, demonstrating that SELENOK is a key player in SMSCs proliferation and differentiation by influencing the Nrf2 antioxidant signaling pathway.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra. Recently, disorders in metabolism of metals, including copper (Cu) and iron (Fe), have been reported to be linked to the pathogenesis of PD. We previously demonstrated that 6-hydoroxydopamine (6-OHDA), a neurotoxin used for the production of PD model animals, decreases Atox1, a Cu chaperone, and ATP7A, a Cu transporter, and disrupts intracellular Cu metabolism in human neuroblastoma SH-SY5Y cells. However, the exact mechanisms remain unclear. Meanwhile, intracellular Fe modulates 6-OHDA-induced cellular responses. In this study, we investigated whether Fe participates in 6-OHDA-induced abnormality in Cu metabolism. 6-OHDA-induced reactive oxygen species (ROS) production and cellular injury were suppressed by Fe chelators, deferoxamine and 2,2'-bipyridyl (BIP). These chelators also restored 6-OHDA-induced degradation of Atox1 and ATP7A proteins and subsequent Cu accumulation, indicating that intracellular Fe is involved in the disruption of Cu homeostasis associated with 6-OHDA. Atox1 has redox-sensitive cysteine (Cys) residues in its Cu-binding site. The Cys residues of Atox1 were oxidized by 6-OHDA, and BIP suppressed their oxidation. Moreover, the replacement of Cys with histidine in the Cu-binding site conferred resistance to 6-OHDA-induced Atox1 degradation. These results suggest that oxidized modification of Atox1 by 6-OHDA is likely to accelerate its degradation. Thus, we conclude that Fe and Cu metabolisms are closely related to each other in the pathogenesis of PD.

Iron oxide (Fe-O) has anti-tumor properties, due to its ability of catalyzing hydrogen peroxide (H₂O₂) of tumor cells to generate reactive oxygen species (ROS) and then cause ferroptosis. Its anti-tumor performance is restricted due to insufficient H₂O₂ in tumor cells. A nanomedicine, Au nanoparticles (NPs) grown on Fe-O, was integrated into poly-l-lactide (PLLA) scaffolds. Results indicated that Au NPs could consume glucose of tumor cells to produce H₂O₂, which supplemented reaction substrate. PLLA/Au@Fe-O scaffold showed enhanced anti-tumor activities against MG63, including increased mortality, decreased migration and colony formation. PLLA/Au@Fe-O scaffold promoted ferroptosis in MG63, including up-regulation of COX-2 protein, down-regulation of FTH1 protein and GPX4 protein. PLLA/Au@Fe-O scaffold also promoted autophagy in MG63, including down-regulation of P62 protein, and up-regulation of LC3BII/I. Mechanistically, PLLA/Au@Fe-O scaffold possessed enhanced anti-tumor activities through promoting ferroptosis and autophagy.

The concept of dual-state hyper-energy metabolism characterized by elevated glycolysis and OxPhos has gained considerable attention during tumor growth and metastasis in different malignancies. However, it is largely unknown how such metabolic phenotypes influence the radiation response in aggressive cancers. Therefore, the present study aimed to investigate the impact of hyper-energy metabolism (increased glycolysis and OxPhos) on the radiation response of a human glioma cell line. Modulation of the mitochondrial electron transport chain was carried out using a 2,4-dinitrophenol (DNP). Metabolic characterization was carried out by assessing glucose uptake, lactate production, mitochondrial mass, membrane potential, and ATP production. The radiation response was examined by cell growth, clonogenic survival, and cell death assays. Macromolecular oxidation was assessed by DNA damage, lipid peroxidation, and protein carbonylation assay. Hypermetabolic OPM-BMG cells exhibited a significant increase in glycolysis and OxPhos following irradiation as compared to the parental BMG-1 cells. Enhanced radioresistance of OPM-BMG cells was evidenced by the increase in α/β ratio (9.58) and D1 dose (4.18 Gy) as compared to 4.36 and 2.19 Gy in BMG-1 cells respectively. Moreover, OPM-BMG cells were found to exhibit increased resistance against radiation-induced cell death, and macromolecular oxidation as compared to BMG-1 cells. Inhibition of glycolysis and mitochondrial complex-II significantly enhanced the radiosensitivity of OPM-BMG cells compared to BMG-1 cells. Our results demonstrate that the hyper-energy metabolism of increased glycolysis and OxPhos confer radioresistance. Consequently targeting glycolysis and OxPhos in combination with radiation may overcome therapeutic resistance in aggressive cancers like glioma.

Both mothers and infants experience oxidative stress due to gestational diabetes mellitus (GDM), which is strongly associated with adverse pregnancy outcomes. Ferroptosis, a novel form of programmed cell death characterized by iron-dependent lipid peroxidation, is believed to play a critical role in the pathogenesis and progression of GDM. Metformin (MET) has shown potential in alleviating oxidative stress; however, research on its specific mechanisms of action in GDM remains limited. We collected placental tissues from GDM patients and healthy controls and established an in vitro GDM cell model. We measured markers of ferroptosis including malondialdehyde (MDA), glutathione (GSH), and glutathione peroxidase 4 (GPX4) activity. Additionally, we evaluated reactive oxygen species (ROS) levels, apoptosis, cell viability, and migration in the cell model. Our findings revealed significant changes in the GDM group compared to controls, including increased MDA and GSSG levels, decreased GSH levels, and reduced expression of GPX4 protein in the GDM placenta. High-glucose (HG) conditions were shown to reduce trophoblast cell viability and migration, accompanied by elevated ROS and MDA levels, as well as reduced expression of GSH, GPX4, Nrf2, and HO-1 proteins. Importantly, treatment with MET reversed these effects, similar to the action of deferoxamine mesylate (DFOM), a known ferroptosis inhibitor. These results confirm the occurrence of ferroptosis in the placentas of GDM patients and demonstrate that MET mitigates high-glucose-induced ferroptosis in trophoblasts through the Nrf2/HO-1 signaling pathway. This study provides novel insights into the protective mechanisms of MET, offering potential therapeutic strategies for GDM. management.