Reactive Oxygen Species Levels Research Articles

Experimental Lung Transplantation Related With HIF-1, VEGF, ROS. Assessment of HIF-1α, VEGF, and Reactive Oxygen Species After Competitive Blockade of Chetomin for Lung Transplantation in Rats

Primary graft failure occurs 15 to 30 % of the time after transplantation. Although there have been improvements in preserving the lungs in good condition, there have not been studies on the regulation of transcription factors. Methods: We carried out an experimental study involving lung transplantation to indirectly evaluate reactive oxygen species (ROS) production and VEGF expression by competitive blockade of HIF-1α with chetomin. There were 5 groups: Group-1: Lung blocks were perfused with 0.9 % SSF, immediately harvested, and preserved. Group-2 (I-T): Immediate transplantation and then reperfusion for 1 h. Group-3 (I-R): Lung blocks were harvested and preserved in LPD solution for 6 h and reperfused for 1 h. Group-4 (DMSO): Lung blocks were treated for 4 h with DMSO, preserved for 6 h and transplanted to a receptor treated with DMSO. Group-5 (chetomin): Lung blocks were treated for 4 h with chetomin, preserved for 6 h and transplanted to a receptor treated with chetomin. ROS, mRNA, and protein levels of HIF-1α and EG-VEGF were determined. Results: The DMSO and chetomin groups had significantly lower ROS levels. Compared with those in the I-R group, the chetomin group exhibited the lowest level of HIF-1α. Conclusions: Addition of chetomin to the donor and the receptor results in a significant reduction in HIF-1A, VEGF and ROS.

The regulatory network and critical factors promoting programmed cell death during embryogenesis.

Programmed cell death (PCD) is essential for animal and plant development. However, the knowledge of the mechanism regulating PCD in plants remains limited, largely due to technical limitations. Previously, we determined that the protease NtCP14 could trigger PCD in the embryonic suspensor of tobacco (Nicotiana tabacum), providing a unique opportunity to overcome the limitations by creating synchronous two-celled proembryos with ongoing PCD for transcriptome analysis and regulatory factor screening. Here, we performed comparative transcriptome analysis using isolated two-celled proembryos and explored the potential regulatory network underlying NtCP14-triggered PCD. Multiple phytohormones, calcium, microtubule organization, the immunity system, soluble N-ethylmaleimide-sensitive factor attachment protein receptor proteins, long non-coding RNAs and alternative splicing are addressed as critical factors involved in the early stage of suspensor PCD. Genes thought to play crucial roles in suspensor PCD are highlighted. Notably, decreased antioxidant gene expression and increased reactive oxygen species (ROS) levels during suspensor PCD suggest a critical role for ROS signaling in the initiation of NtCP14-triggered PCD. Furthermore, five genes in the regulatory network are recommended as immediate downstream elements of NtCP14. Together, our analysis outlines an overall molecular network underlying protease-triggered PCD and provides a reliable database and valuable clues for targeting elements immediately downstream of NtCP14 to overcome technical bottlenecks and gain deep insight into the molecular mechanism regulating plant PCD.

The role of COX2 deficiency attenuates cardiac damage in acute myocardial infarction

Cardiac cell damage frequently occurs as a consequence of acute myocardial infarction (AMI), a critical complication of coronary atherosclerotic heart disease. There is an escalating recognition of the association between COX2 and myocardial damage induced by ischemia. The objective of this study is to investigate the inhibitory effect of the COX2 on cardiomyocyte damage in the context of AMI. To create an AMI model, mice with the genetic background of wild-type C57BL6/J (WT) and COX2-/- mice were utilized. The left anterior descending (LAD) coronary artery in their hearts was obstructed, and subsequent assessment of hemodynamic parameters and heart function was conducted. Notably, increased levels of COX2 were observed in AMI mice. Through correlational analysis between COX2 expression and cardiac function following AMI, it was revealed that COX2 knockout mice had smaller infarct sizes, better cardiac performance, and suppressed levels of reactive oxygen species (ROS) compared to WT mice. Additionally, we discovered that COX2 knockout mice exhibited significantly higher mRNA levels of smooth muscle actin, collagen I, and collagen III than normal mice with AMI. Conversely, the levels of superoxide dismutase (SOD), malondialdehyde (MDA) were higher but iron content was decreased in COX2 knockout mice compared to normal mice with AMI.In summary, our research demonstrates that the downregulation of COX2 enhances cardiac tissue recovery in the context of AMI.

Mir-509-3p targets SLC25A13 to regulate ferroptosis and protect retinal endothelial cells in diabetic retinopathy.

Diabetic retinopathy (DR) is a major complication of diabetes that leads to vision impairment. The aim of this study was to investigate the regulatory role of miR-509-3p in DR, focusing on its interaction with SLC25A13 and its impact on retinal endothelial cell function, oxidative stress, apoptosis, and ferroptosis. HRVECs were cultured in high-glucose (HG) conditions to establish an in vitro DR model. miR-509-3p mimics and inhibitors were transfected into HRVECs to assess their effects on SLC25A13 expression, cell viability, apoptosis, reactive oxygen species (ROS) levels, and ferroptosis markers. A luciferase reporter assay and RNA immunoprecipitation were used to confirm the binding of miR-509-3p to SLC25A13 mRNA. For in vivo validation, agomiR-509-3p was injected into the vitreous of DR mice, and retinal thickness, pathological damage, and apoptosis were evaluated. Ferroptosis-related markers (GPX4, TlR4, ASCL4) were analyzed in HRVECs to explore the mechanism of miR-509-3p in regulating ferroptosis. In vitro, miR-509-3p significantly decreased SLC25A13 expression, resulting in enhanced HRVEC viability, reduced apoptosis, and lower ROS levels under HG conditions. Overexpression of SLC25A13 reversed these protective effects, while miR-509-3p knockdown exacerbated oxidative stress and apoptosis. In vivo, agomiR-509-3p increased retinal thickness, reduced pathological damage, and decreased apoptosis in DR mice. Ferroptosis marker analysis revealed that miR-509-3p upregulated GPX4 expression and downregulated TlR4 and ASCL4, whereas SLC25A13 overexpression reversed these effects, further linking miR-509-3p to the regulation of ferroptosis. miR-509-3p exerts a protective effect in DR by targeting SLC25A13, reducing oxidative stress, apoptosis, and ferroptosis in retinal endothelial cells. These findings highlight the potential of miR-509-3p as a therapeutic target for DR management.

Elucidating the role of CYFIP2 in conferring cisplatin resistance in esophageal squamous cell carcinoma

Cisplatin (CDDP) serves as a vital component in the chemotherapeutic approach to treat esophageal squamous cell carcinoma (ESCC). However, prolonged CDDP application frequently culminates in resistance, compromising therapeutic outcomes. Through genome-wide CRISPR library screening, our study elucidates the mechanisms underlying this resistance, pinpointing CYFIP2 as a pivotal mediator. Notably, the involvement CYFIP2 is characterized by pronounced autophagic activity and the modulation of multiple cellular pathways. Empirical validation was achieved by treating ESCC cell lines with CDDP, which resulted in an upsurge of CYFIP2 expression. The functional impact of CYFIP2 was further delineated through knockdown experiments, where a marked suppression in cell proliferation was observed, alongside a discernible decline in reactive oxygen species levels. This was complemented by a suite of assays and microscopic techniques, including GFP-LC3, mRFP-GFP-LC3, electron microscopy and western blot, which collectively affirmed the inhibitory effect of CYFIP2 knockdown on autophagic processes, particularly impeding autophagosome formation and their subsequent fusion with lysosomes. In vivo studies have also confirmed that CYFIP2 knockdown limits tumor progression and increases CDDP efficacy. Conclusively, our findings introduce CYFIP2 as a novel contributor to CDDP resistance in ESCC, underscoring its potential as a therapeutic target. This revelation not only deepens our understanding of resistance mechanisms but also paves the way for novel oncotherapeutic strategies, promising enhanced treatment efficacy against ESCC.

β-Ketoenamine covalent organic framework nanoplatform combined with immune checkpoint blockade via photodynamic immunotherapy inhibit glioblastoma progression

The synergistic approach of combining photodynamic immunotherapy with endogenous clearance of PD-L1 immune checkpoint blockade therapy holds promise for enhancing survival outcomes in glioblastoma (GBM) patients. The observed upregulation of O-GlcNAc glycolysis in tumors may contribute to the stabilization of endogenous PD-L1 protein, facilitating tumor immune evasion. This study presents a pH-adapted excited state intramolecular proton transfer (ESIPT)-isomerized β-ketoamide-based covalent organic framework (COF) nanoplatform (denoted as OT@COF-RVG). Temozolomide (TMZ) and OSMI-4 (O-GlcNAc transferase inhibitor) were integrated into COF cavities, then modified on the surface with polyethylene glycol and the rabies virus peptide RVG-29, showing potential for sensitizing TMZ chemotherapy and initiating photodynamic therapy (PDT). By inhibiting O-GlcNAc and promoting lysosomal degradation of PD-L1, OT@COF-RVG enhanced the effectiveness of immune checkpoint blockade (ICB) therapy. Additionally, treatment with OT@COF-RVG led to a notable elevation in reactive oxygen species (ROS) levels, thereby re-establishing an immunostimulatory state, inducing immunogenic cell death (ICD). In summary, our research unveiled a correlation between O-GlcNAc in GBM and the evasion of immune responses by tumors, while showcasing the potential of OT@COF-RVG in reshaping the immunosuppressive microenvironment of GBM and offering a more effective approach to immunotherapy in clinical settings.

Electron-donable heterojunctions with synergetic Ru-Cu pair sites for biocatalytic microenvironment modulations in inflammatory mandible defects

The clinical treatments of maxillofacial bone defects pose significant challenges due to complex microenvironments, including severe inflammation, high levels of reactive oxygen species (ROS), and potential bacterial infection. Herein, we propose the de novo design of an efficient, versatile, and precise electron-donable heterojunction with synergetic Ru-Cu pair sites (Ru-Cu/EDHJ) for superior biocatalytic regeneration of inflammatory mandible defects and pH-controlled antibacterial therapies. Our studies demonstrate that the unique structure of Ru-Cu/EDHJ enhances the electron density of Ru atoms and optimizes the binding strength of oxygen species, thus improving enzyme-like catalytic performance. Strikingly, this biocompatible Ru-Cu/EDHJ can efficiently switch between ROS scavenging in neutral media and ROS generation in acidic media, thus simultaneously exhibiting superior repair functions and bioadaptive antibacterial properties in treating mandible defects in male mice. We believe synthesizing such biocatalytic heterojunctions with exceptional enzyme-like capabilities will offer a promising pathway for engineering ROS biocatalytic materials to treat trauma, tumors, or infection-caused maxillofacial bone defects.

Antibacterial Activity of Phloretin Against Vibrio parahaemolyticus and Its Application in Seafood

Although phloretin is widely utilized in the food industry as an additive, its effects on foodborne pathogens remain insufficiently investigated. This study aimed to evaluate the antimicrobial properties of phloretin (PHL) against Vibrio parahaemolyticus (V. parahaemolyticus) and to elucidate the potential mechanisms of action. After PHL treatment, alterations in the cell morphology, cell microstructure, and intracellular contents of V. parahaemolyticus were assessed. Scanning electron microscopy revealed substantial damage to cell integrity, subsequent to PHL treatment. A notable reduction in intracellular components, including proteins, ATP, and DNA, was observed in samples treated with PHL. PHL was shown to inhibit the activities of ATPase, β-galactosidase, and respiratory chain dehydrogenase in V. parahaemolyticus. Furthermore, it was demonstrated to elevate the intracellular levels of reactive oxygen species and promote cell death. After being applied to sea bass, shrimp, and oysters, PHL effectively inactivated V. parahaemolyticus in these seafoods. These findings demonstrate that PHL has potential for application in seafood to control V. parahaemolyticus.

Imbalance of redox homeostasis and altered cellular signaling induced by the metal complexes of terpyridine

Compounds that can induce oxidative stress in cancer cells while remaining nontoxic to healthy cells are extremely promising for potential anticancer drugs. 2,2′:6′,2′′-terpyridine-metal complexes possess these properties. The high level of activity (IC50 = 0.605 µM) of 2,2′:6′,2′′-terpyridine-metal complexes on lung, breast, pancreatic, and glioblastoma multiforme cancer lines and their selectivity (SI > 41.32) on human normal fibroblasts were confirmed and presented in this paper. The mechanism of action of these compounds is associated with the generation of reactive oxygen species, which affects several cellular pathways and signals. The results demonstrate that 2,2′:6′,2′′-terpyridine-metal complexes affect cell cycle inhibition in the G0/G1 phase as well as the activation of apoptosis and autophagy cell death. These results were confirmed in several independent studies, including experiments measuring the fluorescence levels of reactive oxygen species, flow cytometry, and gene and protein analysis.

Enhancing of Rabbit Sperm Cryopreservation with Antioxidants Mito-Tempo and Berberine

Cryopreservation plays a critical role in animal breeding and the conservation of endangered species, but it often compromises sperm characteristics such as morphology, motility, and viability due to oxidative stress. This study explores the antioxidative effect of Mito-Tempo (MT) and Berberine (BER) to enhance post-thaw sperm quality in rabbits. Pooled rabbit sperm samples were supplemented with different concentrations (0.0, 0.5, 5, 10, 50 µmol/L) of MT and BER. Sperm motility was evaluated using computer-assisted semen analysis, while viability, apoptosis, reactive oxygen species (ROS) levels, acrosome integrity, and mitochondrial function were assessed through flow cytometry. The results revealed that MT at 5 and 10 µmol/L and BER at 10 µmol/L significantly improved total and progressive motility, mitochondrial activity, and sperm viability compared to the control group. Furthermore, 10 µmol/L BER enhanced acrosome integrity, while both 5 µmol/L MT and 10 µmol/L BER effectively reduced ROS levels and apoptosis. This study is the first to demonstrate the protective effects of MT and BER on rabbit sperm during cryopreservation. By mitigating oxidative stress and reducing apoptosis, these antioxidants markedly improved post-thaw sperm quality, positioning MT and BER as promising agents for improving sperm cryosurvival.

Mediterranean Mussels (Mytilus galloprovincialis) Under Salinity Stress: Effects on Antioxidant Capacity and Gill Structure.

Bivalve mollusks frequently experience salinity fluctuations that may drive oxidative stress (OS) in the organism. Here we investigated OS markers and histopathological changes in gills and hemolymph of Mediterranean mussels Mytilus galloprovincialis Lamarck, 1819 exposed to a wide range of salinities (6, 10, 14, 24, and 30 ppt). Mussels were captured at the shellfish farm with the salinity 18 ppt and then exposed to hypo- and hypersaline conditions in the laboratory. Indicators of redox balance in hemocytes (intracellular reactive oxygen species (ROS) levels, DNA damage) and gills (thiobarbituric acid reactive substances (TBARS), protein carbonyls (PC), activity of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) were measured. The effect of salinity stress on microstructure of gills has been evaluated as well. The results revealed induction of OS in tissues and cells of mussels for both experimental increase and decrease salinity modelings. Hemocytes showed higher sensitivity to osmotic stress compared to gills. In gills TBARS were stable in all experimental groups and PC increased only at salinity 6 ppt. The activity of SOD, CAT and GPx in gills decreased only in mussels acclimated to salinity 24 ppt and further salinisation up to 30 ppt was associated with the recovery of the activity of all enzymes. Major histopathological changes in gills upon salinity fluctuations included inflammatory reactions, circulatory alterations, regressive and progressive changes. Our findings clearly indicate that salinity fluctuations promote OS at cellular and tissue level and also affect microstructure of gills in mussels. The results provide new insights into the mechanisms of osmotic stress in bivalves.

New Emerging Therapeutic Strategies Based on Manipulation of the Redox Regulation Against Therapy Resistance in Cancer.

Background: Resistance to standard therapeutic methods, including chemotherapy, immunotherapy, and targeted therapy, remains a critical challenge in effective cancer treatment. Redox homeostasis modification has emerged as a promising approach to address medication resistance. Objective: This review aims to explore the mechanisms of redox alterations and signaling pathways contributing to treatment resistance in cancer. Methods: In this study, a comprehensive review of the molecular mechanisms underlying drug resistance governed by redox signaling was conducted. Emphasis was placed on understanding how tumor cells manage increased reactive oxygen species (ROS) levels through upregulated antioxidant systems, enabling resistance across multiple therapeutic pathways. Results: Key mechanisms identified include alterations in drug efflux, target modifications, metabolic changes, enhanced DNA damage repair, stemness preservation, and tumor microenvironment remodeling. These pathways collectively facilitate tumor cells' adaptive response and resistance to various cancer treatments. Conclusion: Developing a detailed understanding of the interrelationships between these redox-regulated mechanisms and therapeutic resistance holds potential to improve treatment effectiveness, offering valuable insights for both fundamental and clinical cancer research. Antioxid. Redox Signal. 00, 000-000.

A comprehensive analysis of the defense responses of Odontotermes formosanus (Shiraki) provides insights into the changes during Serratia marcescens infection

BackgroundOdontotermes formosanus (Shiraki) is a highly damaging agroforestry pest. Serratia marcescens is a broad-spectrum insecticidal pathogen and is highly lethal to O. formosanus. However, little is known about the mechanism between them. To improve the biological control of pests, a more in-depth analysis of the interactions between the pests and the pathogens is essential.ResultsWe used RNA-seq, enzyme activity assays and real-time fluorescent quantitative PCR (qPCR) to explore the defense responses of O. formosanus against SM1. RNA-seq results showed that 1,160, 2,531 and 4,536 genes were differentially expressed at 3, 6 and 12 h after SM1 infection, and Kyoto Encyclopedia of Genes and Genomes (KEGG) results indicated that immune response and energy metabolism were involved in the defense of O. formosanus against SM1. Reactive oxygen species (ROS) levels and ROS synthesis genes were significantly elevated, and the antioxidant system were induced in O. formosanus after SM1 infection. In addition, the cellular immune genes were affected, and the Toll, immune deficiency (Imd), Janus kinase/signal transducer and activator of transcription (JAK/STAT), c-Jun N-terminal Kinase (JNK) and melanization pathways were activated. In vitro, Oftermicin, an antimicrobial peptide, had a significantly inhibitory effect on SM1. Furthermore, the expression levels and enzyme activities of phosphofructokinase (PFK), lactate dehydrogenase (LDH), succinate dehydrogenase (SDH) and isocitrate dehydrogenase (IDH) in glycolysis and tricarboxylic acid (TCA) cycles were increased.ConclusionsOur results clearly demonstrated that O. formosanus defended against SM1 by activating the antioxidant system, innate immunity and energy metabolism. This study would provide useful information for the development of biological controls of O. formosanus.

Androgen Receptor Mediates Dopamine Agonist Resistance by Regulating Intracellular Reactive Oxygen Species in Prolactin-Secreting Pituitary Adenoma.

Aims: Dopamine agonists (DAs) are the first-line treatment for patients with prolactin-secreting pituitary adenoma (PRL adenoma). However, a subset of individuals exhibits poor responses, known as DA resistance. Previous studies have reported that DA resistance is more prevalent in male patients. This study aims to investigate the relationship between androgen receptor (AR) expression and DA resistance, as well as to explore underlying mechanisms of AR-mediated DA resistance. Results: Our results demonstrated that patients with higher AR expression exhibit greater resistance to DA in our cohort of DA-resistant PRL adenoma. Furthermore, AR was found to be involved in cell proliferation, PRL secretion, and resistance to bromocriptine (BRC) both in vitro and invivo. Mechanistically, we demonstrated that intracellular reactive oxygen species (ROS) function as upstream mediators of apoptosis and ferroptosis following BRC treatment. As a ligand-dependent transcription factor, AR could translocate to the nucleus and transcriptionally promote NFE2-like bZIP transcription factor 2 (NRF2) expression, which regulates intracellular ROS levels, thereby enhancing cell viability and conferring DA resistance to pituitary adenoma (PA) cells. Finally, AR targeting agents were used to inhibit AR signaling, downregulate NRF2 transcription, and sensitize PA cells to BRC treatment. Conclusion and Innovation: We demonstrated that AR plays a crucial role in mediating DA resistance in PRL adenoma. Mechanistically, AR promotes cell proliferation and PRL secretion and confers drug resistance by transcriptionally regulating NRF2 expression to maintain redox homeostasis in PA cells. Finally, combining AR targeting agents with BRC shows promise as a therapeutic strategy for treating PRL adenomas. Antioxid. Redox Signal. 00, 000-000.

Protective Mechanism of Sea buckthorn Proanthocyanidins Against Hydrogen Peroxide-Introduced Oxidative Damage in Adult Retinal Pigment Epithelial-19

Retinal pigment epithelial (RPE) is an oxidation-resistant cell. But if it is subjected to various harmful stimuli for a prolonged period, an excessive amount of oxyradical will be generated to cause retinal dysfunction. We investigated and elucidated the protective mechanism of Sea buckthorn proanthocyanidins (SBP) against oxidative damage in RPE. In this study, we established an oxidative damage model of adult retinal pigment epithelial cell line-19 (ARPE-19) using hydrogen peroxide (H2O2), followed by different concentrations of SBP for 24 h. The finding demonstrated that SBP effectively inhibited the generation of malondialdehyde (MDA), restored the activity of superoxide dismutase (SOD) and content of glutathione (GSH), and significantly eliminated the level of reactive oxygen species (ROS) and oxidative stress. It was revealed that 100 µg/mL of SBP was more suitable for restoring oxidative damage in ARPE-19, which enhanced cell activity and migration ability and maintained normal cell morphology. In addition, SBP increased the expression of Bcl-2, decreased the expression of Bax and caspase-3, and activated the Nrf2/HO-1 signaling pathway to protect ARPE-19 from oxidative stress. Moreover, SBP could restore the morphology and quantity of mitochondria and inhibit mitochondrial permeability and swelling. The present results provide a theoretical basis for the protective and restorative effect of SBP in retinopathy caused by oxidative stress.

Transcriptome-Based Spatiotemporal Analysis of Drought Response Mechanisms in Two Distinct Peanut Cultivars

Drought tolerance varies among different peanut (Arachis hypogaea L.) cultivars. Here, drought responses of two cultivars, Huayu 22 (HY22) with drought tolerance and Fuhua 18 (FH18) with drought sensitivity, were compared at the morphological, physiological, biochemical, photosynthetic, and transcriptional levels. Drought stress caused wilting and curling of leaves, bending of stems, and water loss in both cultivars. There was an increase in malondialdehyde (MDA) content under prolonged drought stress, more so in FH18. But the levels of reactive oxygen species (H2O2) and lipid peroxidation were low in HY22. The activities of superoxide dismutase (SOD), peroxidase (POD), and glutathione reductase (GR) were considerably elevated, corresponding with rapid increases in the accumulation of soluble proteins, soluble sugars, and proline. Transcriptional sequencing showed gene expression varied seriously in HY22, which was upregulated in both stems of two cultivars, though downregulation was less pronounced in HY22. KEGG pathway analysis revealed significant enrichment in four leaf and six stem pathways. Additionally, core genes relating to photosynthesis, carbon fixation, proline synthesis, and sucrose and starch synthesis pathways were identified by correlation analysis. Those gene expressions were variously upregulated in stems of two cultivars, especially in HY22, giving a novel view of the shoot as a whole participating in stress response.

Synergistic effect of curcumin and Piperine loaded Niosomal nanoparticles on acute pulmonary toxicity induced by Paraquat in mice.

Paraquat (PQ), a widely used non-selective herbicide, induces severe lung toxicity by promoting cell death and tissue necrosis through the generation of reactive oxygen species (ROS) and free radicals. This study aimed to develop and evaluate novel niosomal nanoparticles (NPs) encapsulating curcumin and piperine to mitigate PQ-induced acute pulmonary toxicity in Balb/c mice. The NPs were prepared using non-ionic surfactants and cholesterol via the thin film hydration method. Characterization revealed high encapsulation efficiency (>85%), proper particle sizes (264-286nm), narrow polydispersity index (PDI) (0.19±0.04 to 0.23±0.02), and good stability over 90days. Thermal analysis confirmed successful encapsulation of curcumin and piperine within the niosomal NPs. In vivo studies showed that PQ exposure significantly elevated ROS, lipid peroxidation (LPO), and protein carbonylation (PC) levels, while reducing glutathione (GSH) levels and impairing mitochondrial function (P<0.001). However, co-treatment with curcumin- and piperine-loaded niosomal NPs effectively reversed these effects (P<0.001), improving mitochondrial function. The combined formulation of curcumin and piperine in niosomal NPs offers a promising therapeutic strategy for treating PQ-induced pulmonary toxicity, likely due to enhanced bioavailability and potent antioxidant activity.

SntB triggers the antioxidant pathways to regulate development and aflatoxin biosynthesis in Aspergillus flavus.

The epigenetic reader SntB was identified as an important transcriptional regulator of growth, development, and secondary metabolite synthesis in Aspergillus flavus. However, the underlying molecular mechanism is still unclear. In this study, by gene deletion and complementation, we found SntB is essential for mycelia growth, conidial production, sclerotia formation, aflatoxin synthesis, and host colonization. Chromatin immunoprecipitation sequencing (ChIP-seq) and RNA sequencing (RNA-seq) analysis revealed that SntB played key roles in oxidative stress response of A. flavus, influencing related gene activity, especially catC encoding catalase. SntB regulated the expression activity of catC with or without oxidative stress, and was related to the expression level of the secretory lipase (G4B84_008359). The deletion of catC showed that CatC participated in the regulation of fungal morphogenesis, reactive oxygen species (ROS) level, and aflatoxin production, and that CatC significantly regulated fungal sensitive reaction and AFB1 yield under oxidative stress. Our study revealed the potential machinery that SntB regulated fungal morphogenesis, mycotoxin anabolism, and fungal virulence through the axle of from H3K36me3 modification to fungal virulence and mycotoxin biosynthesis. The results of this study shed light into the SntB-mediated transcript regulation pathways of fungal mycotoxin anabolism and virulence, which provided potential strategy to control the contamination of A. flavus and its aflatoxins.

The in vitro effect riboflavin combined with or without UVA in Acanthamoeba castellanii.

The anti-Acanthamoeba properties of riboflavin and its enhanced amoebicidal effects when combined with ultraviolet A (UVA) radiation were investigated in vitro. The viability of cultured Acanthamoeba castellanii was assessed by adding varying concentrations (0 ~ 0.2% w/v) of riboflavin to the culture medium or after combined riboflavin and UVA treatment (30min, 3 mW/cm2) over 1, 3, 5, and 7 days. Intracellular reactive oxygen species (ROS) levels were measured following a 30-minute exposure to riboflavin. Additionally, the cysticidal effects of riboflavin, UVA, and their combination were evaluated. Gene transcription in Acanthamoeba was analyzed using RNA-seq.Riboflavin demonstrated dose-dependent toxicity on Acanthamoeba, accompanied by an increase in intracellular ROS. Exposure to 0.2% riboflavin reduced Acanthamoeba viability by over 50% within one day. UVA treatment alone also reduced viability by over 50%. Combined treatment with 0.2% riboflavin decreased trophozoite survival by more than 80%, and approximately 60% of cysts were killed when 0.1% riboflavin was combined with UVA. RNA-seq analysis indicated significant changes in gene expression after exposure to riboflavin, UVA, and their combination, particularly affecting oxidoreductase activity, cystathionine β synthase, and serine-threonine kinase activity. These findings indicate that riboflavin exhibits dose-dependent toxicity in Acanthamoeba, primarily through increased ROS generation. Combining riboflavin and UVA did not fully eradicate trophozoites and cysts of Acanthamoeba, but was able to partially inactivate them.

Activation of lysosomal Ca2+ channels mitigates mitochondrial damage and oxidative stress.

Elevated levels of plasma-free fatty acids and oxidative stress have been identified as putative primary pathogenic factors in endothelial dysfunction etiology, though their roles are unclear. In human endothelial cells, we found that saturated fatty acids (SFAs)-including the plasma-predominant palmitic acid (PA)-cause mitochondrial fragmentation and elevation of intracellular reactive oxygen species (ROS) levels. TRPML1 is a lysosomal ROS-sensitive Ca2+ channel that regulates lysosomal trafficking and biogenesis. Small-molecule agonists of TRPML1 prevented PA-induced mitochondrial damage and ROS elevation through activation of transcriptional factor EB (TFEB), which boosts lysosome biogenesis and mitophagy. Whereas genetically silencing TRPML1 abolished the protective effects of TRPML1 agonism, TRPML1 overexpression conferred a full resistance to PA-induced oxidative damage. Pharmacologically activating the TRPML1-TFEB pathway was sufficient to restore mitochondrial and redox homeostasis in SFA-damaged endothelial cells. The present results suggest that lysosome activation represents a viable strategy for alleviating oxidative damage, a common pathogenic mechanism of metabolic and age-related diseases.