Free Radical Research最新文献

Cancer genome sequencing studies have identified somatic mutations in the KEAP1/NRF2 pathway. In an effort to identify novel NRF2 small molecule inhibitor(s), we have screened a natural compound library comprising 1330 chemicals in A549-ARE-GFP-luciferase cells and identified that narciclasine significantly inhibits NRF2-dependent luciferase activity. Narciclasine suppressed the expression of NRF2 and NRF2 target genes, caused significant oxidative stress, and sensitized cisplatin-mediated apoptosis in A549 cells. In addition, we have observed that WD Repeat Domain 43 (WDR43) serves as a direct target of narciclasine for the inhibition of NRF2 as narciclasine binds to recombinant WDR43 in vitro and silencing WDR43 attenuated the inhibition of NRF2 by narciclasine in A549 cells. Finally, we observed that administration of narciclasine significantly decreased the growth of A549 xenografts. Together, our results demonstrate that the inhibition of NRF2 by narciclasine is mediated by WDR43 and future studies are necessary to elucidate the exact mechanism of how WDR43 mediates the inhibition of NRF2 by narciclasine.

Free radicals have been implicated in the pathogenesis of cancer along with cardiovascular, neurodegenerative, pulmonary and inflammatory disorders. Further, the relationship between oxidative stress and disease is distinctively established. Clinical trials using anti-oxidants for the prevention of disease progression have indicated some beneficial effects. However, these trials failed to establish anti-oxidants as therapeutic agents due to lack of efficacy. This is attributed to the fact that living systems are under dynamic redox control wherein their redox behavior is compartmentalized and simple aggregation of redox couples, distributed throughout the system, is of miniscule importance while determining their overall redox state. Further, free radical metabolism is intriguingly complex as they play plural roles segregated in a spatio-temporal manner. Depending on quality, quantity and site of generation, free radicals exhibit beneficial or harmful effects. Use of nonspecific, non-targeted, general ROS scavengers lead to systemic elimination of all types of ROS and interferes in cellular signaling. Failure of anti-oxidants to act as therapeutic agents lies in this oversimplification of extremely dynamic cellular redox environment as a static and non-compartmentalized redox state. Rather than generalizing the term "oxidative stress" if we can identify the "type of oxidative stress" in different types of diseases, a targeted and more specific anti-oxidant therapy may be developed. In this review, we discuss the concept of redox dynamics, role and type of oxidative stress in disease conditions, and current status of anti-oxidants as therapeutic agents. Further, we probe the possibility of developing novel, targeted and efficacious anti-oxidants with drug-like properties.

Patients with hypoxemia require high-concentration oxygen therapy. However, prolonged exposure to oxygen concentrations 21% higher than physiological concentrations (hyperoxia) may cause oxidative cellular damage. Pulmonary alveolar epithelial cells are major targets for hyperoxia-induced oxidative stress. In this study, we evaluated the therapeutic potential of the antioxidant N-acetyl-L-cysteine (NAC) for preventing hyperoxia-induced cell death. In vitro experiments were performed using the human lung cancer cell line A549. In brief, NAC-treated and untreated cells were exposed to various concentrations of oxygen (hyperoxia) for different durations. The results indicated that hyperoxia inhibited proliferation and caused cell cycle arrest in A549 cells. It also induced necrosis and autophagy. Furthermore, hyperoxia increased intracellular reactive oxygen species levels and altered mitochondrial membrane potential. Co-treatment with NAC improved the survival of cells exposed to 95% oxygen for 24 h. Experiments performed using a neonatal rat model of acute lung injury confirmed that hyperoxia induced an autophagic response. This study provides evidence for hyperoxia-induced autophagy both in vitro and in vivo. NAC can protect A549 cells from death induced by short-term hyperoxia. Our findings may inform protective strategies against hyperoxia-induced injury in developing lungs-for example, bronchopulmonary dysplasia in premature infants.

This research investigates the interplay between Reactive Oxygen Species (ROS) and Apelin (APLN) in regulating autophagy, with implications for placental cell senescence and apoptosis in pre-eclampsia (PE). We manipulated APLN expression using sgRNA to study its effects on ROS levels and subsequent cellular responses. Our findings reveal that APLN overexpression elevates ROS production, accelerating cellular senescence and apoptosis. In contrast, silencing APLN enhances autophagy, thereby diminishing cellular aging and apoptosis. These outcomes were confirmed in vitro and in vivo experiments, establishing a causative relationship between ROS-mediated APLN modulation and altered placental cell dynamics in PE. The results suggest potential therapeutic targets within the ROS and APLN pathways to alleviate detrimental changes in the placenta, offering new strategies for the clinical management of PE. This study emphasizes the crucial role of autophagy in placental health and sets the stage for future investigations into therapeutic interventions for pregnancy-related complications.

Apelin is an endogenous ligand for the Apelin receptor and is a critical protective effector in myocardial infarction (MI). Nevertheless, these protective mechanisms are not fully understood. Ferroptosis is the major driving factor of MI. This study aimed to investigate the effects and underlying regulatory mechanisms of Apelin on cardiomyocyte ferroptosis in MI. A model of MI was induced in adult C57BL/6J wild type (WT) and Apelin knockout (Apelin^-/-) mice. Cardiac function was examined by echocardiography 4 weeks post-MI. RNA-seq, histochemical analyses, and Western blotting were applied to examine the effects of Apelin knockout on the transcriptome and pathological remodeling following infarction and the molecular mechanisms. Mice neonatal cardiomyocytes (NCMs) were used to establish the serum deprivation/hypoxia (SD/H) model in vitro. Compared with WT mice, Apelin^-/- mice exhibited more severe impairment of cardiac function and increased fibrosis following infarction. Transcriptome and biochemical analyses revealed the involvement of ferroptosis in mediating Apelin function in MI. Ferroptosis-related proteins were significantly increased post-MI in Apelin^-/- mice whereas p-AMPK was greatly decreased. Apelin treatment activated the AMPK pathway and thereby inhibited ferroptosis of NCMs induced by SD/H in vitro. These protective effects were partially reversed by AMPK inhibitor. Apelin deficiency aggravated cardiac dysfunction following infarction by activating cardiomyocyte ferroptosis via inhibition of the AMPK pathway. This offers a novel potential therapeutic target for MI treatment.

In this study, a quantum chemical exploration was conducted to assess the antioxidant activity of xanthones isolated from marine sources, focusing on thermodynamics and kinetics within simulated physiological environments. DFT analysis revealed that xanthones such as 1,4,7-trihydroxy-6-methylxanthone (1), 1,4,5-trihydroxy-2-methylxanthone (2), arthone C (3), 2,3,4,6,8-pentahydroxy-1-methylxanthone (4), sterigmatocystin (5), oxisterigmatocystin C (6), and oxisterigmatocystin D (7) favor the SPLET pathway in water and the FHT pathway in lipid environments. The kinetic study of these xanthones reacting with the hydroperoxyl radical (HOO•) was conducted using the formal hydrogen atom transfer (FHT) mechanism and the single electron transfer (SET) mechanism. The results showed that compounds 1-4 exhibited antioxidant activities in aqueous environments surpassing that of the reference compound Trolox, with rate constants ranging from 2.02 x 10⁵ to 9.44 x 10⁷ M^-1·s^-1. In lipid environments, compounds 1 and 2 also demonstrated higher rate constants than Trolox. Additionally, molecular docking and molecular dynamics analysis suggested that xanthones 1-7 potentially inhibit the pro-oxidant effect of the Keap1 enzyme, highlighting their promise as both antiradicals and enzyme inhibitors.

Plasma, which was coined by Irving Langmuir in 1928, is the fourth physical state after the solid/liquid/gas phases. Low-temperature plasma (LTP) is a contradictory condition that involves high energy with free radicals at near-body temperatures and was developed through engineering in the 1990's. Research on LTP in engineering and medical fields has rapidly developed since the 2000's. LTP can be applied through direct or indirect exposure, and there are advantages to both methods. In the medical field, LTP has been found to exert several effects, such as wound healing, hemostasis and anticancer effects, mainly based on different levels of oxidative stress. In the dental field, studies have been performed on LTP applications for general dental procedures, such as restorative, periodontal and prosthodontic procedures, and for oral cancer treatment. Many studies have demonstrated the effectiveness of LTP. Compared with other organs, the anatomical characteristic of the oral cavity is easy direct observation, which is highly advantageous for clinical applications. Due to its good accessibility and efficiency, plasma dentistry is expected to be applied to various dental applications in clinics in the near future.

Urban aerosol particulate matter (UPM) is widespread in the environment, and its concentration continues to increase. Several recent studies have reported that UPM results in premature cellular senescence, but few studies have investigated the molecular basis of UPM-induced senescence in retinal pigment epithelial (RPE) cells. In this study, we primarily evaluated UPM-induced premature senescence and the protective function of nuclear factor erythroid 2-related factor 2 (Nrf2) in human RPE ARPE-19 cells. The findings indicated that UPM exposure substantially induced premature cellular senescence in ARPE-19 cells, as observed by increased β-galactosidase activity, expression levels of senescence-associated marker proteins, and senescence-associated phenotypes. Such UPM-induced senescence is associated with mitochondrial oxidative stress-mediated phosphatidylinositol 3'-kinase/Akt/Nrf2 downregulation. Sulforaphane-mediated Nrf2 activation Sulforaphane-mediated upregulation of phosphorylated Nrf2 suppressed the decrease in its target antioxidant gene, NAD(P)H quinone oxidoreductase 1, under UPM, which notably prevented ARPE-19 cells from UPM-induced cellular senescence. By contrast, Nrf2 knockdown exacerbated cellular senescence and promoted oxidative stress. Collectively, our results demonstrate the regulatory role of Nrf2 in UPM-induced senescence of RPE cells and suggest that Nrf2 is a potential molecular target.

Oxidative stress can be alleviated by antioxidants intakes. Taraxerol acetate (TA), a natural triterpenoid extracted from dandelions, may reduce the risk of metabolic disorders by regulating oxidative stress. In the study, we investigated the effects of TA in relieving oxidative stress in murine intestinal epithelial cells using multiomics techniques. Here, we found that TA activated the antioxidant defense system. Total antioxidant capacity (T-AOC) and Catalase (CAT) activity notably increased after TA treatment. Additionally, TA treatment effectively reduced the levels of lactate dehydrogenase (LDH) and malonaldehyde (MDA) and alleviated H₂O₂-induced oxidative stress. Furthermore, TA induced significant changes in the levels of 30 important metabolites. Specifically, it activated the complement and coagulation cascades, NF-κB and MAPK and glycerophospholipid pathways, resulting in altered transcript levels of related genes, such as Serpinb9e, SCD2, Hspa1b, and Hspa1a. Thus, the results demonstrated that TA potentially could promote health by alleviating H₂O₂-induced oxidative damage and provide valuable insights for its further development.

Diabetic foot wounds associated with oxidative stress are treated with hyperbaric oxygen (HBO), but that may also induce the stress itself; therefore, we studied the effect of HBO treatments on the oxidant-antioxidant balance in the venous blood of patients with diabetic foot syndrome. In addition, blood counts were also examined. 14 male patients (24-74 years), at risk of lower limb amputation were treated with 30 HBO procedures (60 min of the inhalation of pure oxygen at a pressure of 2.5 atm per day, 5 days a week). The control group consisted of 29 healthy male volunteers aged 25-69 years. No members of the group had been subjected to HBO therapy previously (ClinicalTrials.gov, no. NCT06401941). The analyzed redox parameters did not change during the experiment in the patients (p > 0.05). The concentration of thiobarbituric acid reactive substances (TBARS) in the plasma was higher in the patients before the first and after the thirtieth HBO treatments when compared to the control group. In contrast, the TBARS concentration in erythrocytes was lower in the patients after the first treatment vs. the controls. Moreover, the higher activity of catalase in the patients' erythrocytes was noted before the therapy and after the first and last treatments compared to the controls. HBO therapy increased the percentage of monocytes and platelet volume, but it decreased the volume of platelets in the patients' blood. HBO therapy does not affect the oxidant-antioxidant balance disturbed in diabetic foot patients.