Intracellular Reactive Oxygen Species Accumulation Research Articles

Differential inhibition of tire wear particles on sludge dewatering by aging modes

The study assessed the acute toxicities of tire wear particles (TWPs) on activated sludge, comparing cryogenically ground TWPs (C-TWPs) with photo-aged (PA-TWPs), ozone-aged (OA-TWPs), and Fenton-aged (FA-TWPs) variants over 96hours. At 0.1mg/L, TWPs showed no significant effects on sludge respiration or purification. However, at 50mg/L, significant impacts on respiration, decontamination capacity, and microbial community structure were observed, particularly in aged TWPs. Specifically, aged TWPs, especially FA-TWPs, are prone to inducing necrosis by generating non-cellular reactive oxygen species (ROS) catalyzed by persistent free radicals, leading to an increase in lactate dehydrogenase release ranging from 215% to 284%. Conversely, C-TWPs tend to trigger apoptosis via intracellular ROS accumulation, leading to a 358% increase in intracellular ROS. Aged TWPs exhibited higher affinities for proteins and polysaccharides, while C-TWPs preferred phospholipids. All TWPs adversely affected sludge dewatering, with strong correlations found between specific resistance to filtration (SRF) and total protein (r=0.981, p<0.001) and between bound water and early cell apoptosis (r=0.961, p<0.01). Additionally, a correlation between SRF and cellular necrosis (r=0.956, p<0.01) was noted, linked to increased protein and extracellular polymeric substance levels. These results emphasize substantial influence of aged TWPs on sludge dewatering efficiency via diverse bacterial cell death mechanisms.

Activity of the Caged Xanthone Morellic Acid against Vancomycin-Resistant Enterococcus Infection by Targeting the Bacterial Membrane.

Vancomycin-resistant Enterococcus (VRE) is an important nosocomial opportunistic pathogen that is associated with multidrug resistance. Here, we demonstrate that morellic acid inhibits VRE by restoring its sensitivity to vancomycin and ampicillin with low drug resistance and efficient biofilm clearance effects. Morellic acid binds to inner membrane phospholipids, such as phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and cardiolipin (CL) of VRE, such that the fluidity and proton-motive force (PMF) interfere with the damaged inner membrane, causing intracellular reactive oxygen species (ROS) accumulation and bacterial death. Transcriptional analyses supported this effect on inner membrane-related pathways such as fatty acid biosynthesis and glycerophospholipid metabolism. Moreover, morellic acid significantly eliminated residual bacteria in the spleen, liver, kidneys, and abdominal effusion in mice. Our findings indicate the potential applications of morellic acid as an antibacterial agent or adjuvant for treating VRE infections.

Combined blockade of GPX4 and activated EGFR/HER3 bypass pathways inhibits the development of ALK-inhibitor-induced tolerant persister cells in ALK-fusion-positive lung cancer.

Cancers can develop resistance to treatment with ALK tyrosine kinase inhibitors (ALK-TKIs) via emergence of a subpopulation of drug-tolerant persister (DTP) cells that can survive initial drug treatment long enough to acquire genetic aberrations. DTP cells are thus a potential therapeutic target. We generated alectinib-induced DTP cells from a patient-derived ALK+ non-small-cell lung cancer (NSCLC) cell line and screened 3114 agents in the anticancer compounds library (TargetMol). We identified phospholipid hydroperoxide glutathione peroxidase GPX4 as being involved in promoting the survival of DTP cells. GPX4 was found to be upregulated in DTP cells and to promote cell survival by suppressing reactive oxygen species (ROS) accumulation; GPX4 inhibitors blocked this upregulation and facilitated ROS-mediated cell death. Activated bypass signals involving epidermal growth factor receptor (EGFR)/receptor tyrosine-protein kinase erbB-3 (HER3) were also identified in DTP cells, and co-treatment with EGFR-TKI plus ALK-TKI enhanced ROS levels. Triple combination with an ALK-TKI plus a bypass pathway inhibitor plus a GPX4 inhibitor suppressed cell growth and induced intracellular ROS accumulation more greatly than did treatment with each agent alone. The combined inhibition of ALK plus inhibition of activated bypass signals plus inhibition of GPX4 may be a potent therapeutic strategy for patients with ALK+ NSCLC to prevent the development of resistance to ALK-TKIs and lead to tumor eradication.

N-Acetyl-L-Cysteine (NAC) Blunts Axitinib-Related Adverse Effects in Preclinical Models of Glioblastoma.

Axitinib is a tyrosine kinase inhibitor characterized by a strong affinity for Vascular Endothelial Growth Factor Receptors (VEGFRs). It was approved in 2012 by Food and Drug Administration and European Medicines Agency as a second line treatment for advanced renal cell carcinoma and is currently under evaluation in clinical trial for the treatment of other cancers. Glioblastoma IDH-wild type (GBM) is a highly malignant brain tumor characterized by diffusely infiltrative growth pattern and by a prominent neo-angiogenesis. In GBM, axitinib has demonstrated a limited effectiveness as a monotherapy, while it was recently shown to significantly improve its efficacy in combination treatments. In preclinical models, axitinib has been reported to trigger cellular senescence both in tumor as well as in normal cells, through a mechanism involving intracellular reactive oxygen species (ROS) accumulation and activation of Ataxia Telangiectasia Mutated kinase (ATM). Limiting axitinib-dependent ROS increase by antioxidants prevents senescence specifically in normal cells, without affecting tumor cells. We used brain tumor xenografts obtained by engrafting Glioma Stem Cells (GSCs) into the brain of immunocompromised mice, to investigate the hypothesis that the antioxidant molecule N-Acetyl-L-Cysteine (NAC) might be used to reduce senescence-associated adverse effects of axitinib treatment without altering its anti-tumor activity. We demonstrate that the use of the antioxidant molecule N-Acetyl-Cysteine (NAC) in combination with axitinib stabilizes tumor microvessels in GBM tumor orthotopic xenografts, eventually resulting in vessel normalization, and protects liver vasculature from axitinib-dependent toxicity. Overall, we found that NAC co-treatment allows vessel normalization in brain tumor vessels and exerts a protective effect on liver vasculature, therefore minimizing axitinib-dependent toxicity.

Regulation of yeast &lt;i&gt;RAD9&lt;/i&gt; gene in energy charge, intracellular ROS, and cell cycle arrest in response to DNA damage

In various environmental conditions, eukaryotic cells are exposed to many kinds of exogenous toxic agents as well as to endogenous agents like reactive oxygen species (ROS) generated from oxidative metabolism that can all result in damage to DNA. To cope with these types of damage, yeast cells have evolved a number of mechanisms and specific response systems regulated by key control genes. One of which is RAD9 gene that regulates DNA damage and repair checkpoints, and cell cycle arrest. Thus, a series of methods, e.g. oxygen consumption monitoring, physicochemical analysis, and flow cytometry, were used in the present study to investigate the role of the RAD9 gene by using the BY4742 (wild type) and specific knock-out yeast strains (∆rad9) and elucidate the function of this gene in cellular defense mechanism and metabolic response to DNA damage triggered by methyl methanesulfonate (MMS) treatment. The results indicated that fully functional DNA damage repair and cell cycle checkpoint (RAD9, wild type) significantly enhanced mitochondrial activity and oxygen consumption, reduced intracellular ROS accumulation. Fully functional mitochondria attenuated ROS accumulation, enabled efficient mitochondrial electron transport chain (mtETC) and ATP synthesis, and stabilized cellular energy status. Also, high mitochondrial activity acted as a protective mechanism against oxidative stress. In contrast, deletion of the RAD9 (∆rad9) resulted in high ROS accumulation and damaged to mitochondrial DNA, leading to strong inhibition of mitochondrial activity and oxygen consumption. Furthermore, low mitochondrial activity in cells lacking RAD9 (∆rad9) led to the development of oxidative stress. Subsequently, high ROS accumulation in ∆rad9 cells caused a block of the mtETC, repression of ATP synthesis, fluctuation of cellular energy status, and induction of cell cycle arrest at S and G2/M phases.

Lactobacillus delbrueckii subsp. bulgaricus 1.0207 Exopolysaccharides Attenuate Hydrogen Peroxide-Induced Oxidative Stress Damage in IPEC-J2 Cells through the Keap1/Nrf2 Pathway.

Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) is one of the most commonly employed Lactobacillus in the food industry. Exopolysaccharides (EPS) of Lactobacillus, which are known to exhibit probiotic properties, are secondary metabolites produced during the growth of Lactobacillus. This study identified the structure of the EPS produced by L. bulgaricus 1.0207 and investigated the mitigation of L. bulgaricus 1.0207 EPS on H2O2-induced oxidative stress in IPEC-J2 cells. L. bulgaricus 1.0207 EPS consisted of glucose and galactose and possessed a molecular weight of 4.06 × 104 Da. L. bulgaricus 1.0207 EPS exhibited notable scavenging capacity against DPPH, hydroxyl radicals, superoxide anions, and ABTS radicals. Additionally, L. bulgaricus 1.0207 EPS enhanced cell proliferation, reduced intracellular reactive oxygen species (ROS) accumulation, increased activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and total antioxidant capacity (T-AOC) elevated the relative expression of CAT, SOD, HO-1, NQO1, ZO-1, and Occludin genes. Moreover, L. bulgaricus 1.0207 EPS improved the expression of Nrf2, pNrf2, pNrf2/Nrf2, and Bcl-2 proteins, while decreasing the expression of Keap1, Caspase3, and Bax proteins, with the best effect at a concentration of 100 μg/mL. L. bulgaricus 1.0207 EPS mitigated H2O2-induced oxidative stress injury in IPEC-J2 cells by activating the Keap1/Nrf2 pathway. Meanwhile, L. bulgaricus 1.0207 EPS exhibited the potential to decrease apoptosis and restore the integrity of the gut barrier. The findings establish a theoretical foundation for the development and application of L.bulgaricus 1.0207 and its EPS.

Energy Metabolism Enhance Perylenequinone Biosynthesis in Shiraia sp. Slf14 through Promoting Mitochondrial ROS Accumulation.

Perylenequinones (PQs) are important natural compounds that have been extensively utilized in recent years as agents for antimicrobial, anticancer, and antiviral photodynamic therapies. In this study, we investigated the molecular mechanisms regulating PQ biosynthesis by comparing Shiraia sp. Slf14 with its low PQ titer mutant, Slf14(w). The results indicated that the strain Slf14 exhibited a higher PQ yield, a more vigorous energy metabolism, and a more pronounced oxidation state compared to Slf14(w). Transcriptome analysis consistently revealed that the differences in gene expression between Slf14 and Slf14(w) are primarily associated with genes involved in redox processes and energy metabolism. Additionally, reactive oxygen species (ROS) were shown to play a crucial role in promoting PQ synthesis, as evidenced by the application of ROS-related inhibitors and promoters. Further results demonstrated that mitochondria are significant sources of ROS, which effectively regulate PQ biosynthesis in Shiraia sp. Slf14. In summary, this research revealed a noteworthy finding: the higher energy metabolism of the strain Slf14 is associated with increased intracellular ROS accumulation, which in turn triggers the activation and expression of gene clusters responsible for PQ synthesis.

Glutathione peroxidase 3 is essential for countering senescence in adipose remodelling by maintaining mitochondrial homeostasis

Adipose tissue senescence is a precursor to organismal aging and understanding adipose remodelling contributes to discovering novel anti-aging targets. Glutathione peroxidase 3 (GPx3), a critical endogenous antioxidant enzyme, is diminished in the subcutaneous adipose tissue (sWAT) with white adipose expansion. Based on the active role of the antioxidant system in counteracting aging, we investigated the involvement of GPx3 in adipose senescence. We determined that knockdown of GPx3 in adipose tissue by adeno-associated viruses impaired mitochondrial function in mice, increased susceptibility to obesity, and exacerbated adipose tissue senescence. Impairment of GPx3 may cause mitochondrial dysfunction through inner mitochondrial membrane disruption. Adipose reshaping management (cold stimulation and intermittent diet) counteracted the aging of tissues, with an increase in GPx3 expression. Overall metabolic improvement induced by cold stimulation was partially attenuated when GPx3 was depleted. GPx3 may be involved in adipose browning by interacting with UCP1, and GPx3 may be a limiting factor for intracellular reactive oxygen species (ROS) accumulation during stem cell browning. Collectively, these findings emphasise the importance of restoring the imbalanced redox state in adipose tissue to counteract aging and that GPx3 may be a potential target for maintaining mitochondrial homeostasis and longevity.

Tricholoma matsutake heptapeptide prevents gastric mucosa injury by regulating oxidative stress‐related mitochondrial function and mucous layer integrity

AbstractShort‐term excessive alcohol consumption easily leads to ethanolic gastric injury. Recent research on bioactive functional factors in preventing and treating ethanol‐induced acute gastric injury has garnered attention. This study explored the direct protective effects of the Tricholoma matsutake‐derived peptide Ser–Ala–Pro–Trp–Gly–Leu–Ala (SAPWGLA) on ethanol‐induced acute gastric damage. The results showed that SAPWGLA showed dose‐dependent protection against gastric mucosal injury, including the regulation of oxidative stress and mitochondrial function, as well as the enhancement of mucosal barrier integrity. SAPWGLA maintained normal mitochondrial metabolism by alleviating intracellular reactive oxygen species (ROS) accumulation; 400 mg/mL SAPWGLA reduced ROS levels by 81.72 ± 1.55% and reversed the decrease of MMP by ethanol to 1.22 ± 0.01 (J‐aggregates/monomer) in GES‐1 cells. Also, SAPWGLA enhanced the tight junctions between GES‐1 cells. In addition, SAPWGLA improved the integrity of the mucosal barrier by maintaining the balance of the mucus layer and regulating the expression of TJ proteins. Daily oral administration of SAPWGLA (50 mg/kg) exhibited a restoration in hexosamine to 10.76 ± 0.73 mg/g prot, a regulation in claudin‐1, occludin, and ZO‐1 (1.21‐, 1.39‐, and 0.73‐fold of the control group). These findings suggest that SAPWGLA can be a potential novel therapeutic approach to dealing with acute gastric injury caused by ethanol.

Synthesis and Evaluation of Novel 1-Methyl-1H-pyrazol-5-amine Derivatives with Disulfide Moieties as Potential Antimicrobial Agents.

Sulfur-containing compounds have diverse biological functions and are crucial in crop protection chemistry. In this study, a series of novel 1-methyl-1H-pyrazol-5-amine derivatives incorporating disulfide moieties were synthesized and evaluated for their antimicrobial properties. In vitro bioassays demonstrated that compound 7f displayed potent antifungal activity against Valsa mali, with an EC50 value of 0.64 mg/L, outperforming allicin (EC50 = 26.0 mg/L) but lower than tebuconazole (EC50 = 0.33 mg/L). In vivo experiments confirmed that compound 7f could effectively inhibit V. mali infection on apples at a concentration of 100 mg/L, similar to the positive control tebuconazole. Mechanistic studies revealed that compound 7f could induce hyphal shrinkage and collapse, trigger intracellular reactive oxygen species accumulation, modulate antioxidant enzyme activities, initiate lipid peroxidation, and ultimately cause irreversible oxidative damage to the cells of V. mali. Additionally, compound 7b exhibited notable antibacterial activity, particularly against Pseudomonas syringae pv. actinidiae, with a MIC90 value of 1.56 mg/L, surpassing the positive controls allicin, bismerthiazol, and streptomycin sulfate. These findings suggest that 1-methyl-1H-pyrazol-5-amine derivatives containing disulfide moieties hold promise as potent candidates for the development of novel antimicrobial agents.

Optimizing therapeutic efficacy of antifungal peptides via strategic terminal amino acid modification

IntroductionAntifungal peptides (AFPs) have the potential to treat antifungal-resistant infections; however, their structure–function relationship remains unknown, hindering their rapid development. Therefore, it is imperative to investigate and clarify the structure–function relationships of AFPs. ObjectivesThis study aimed to investigate the impact of end-tagging single hydrophobic amino acids and capping the N-terminus with glycine (Gly) on the antifungal activity of peptide W4. MethodsThe antifungal efficacy of the engineered peptides was initially assessed by determining the minimum inhibitory concentration (MIC) /minimal fungicidal concentration (MFC), killing kinetics, and drug resistance induction, in addition to evaluating the biocompatibility and stability. Subsequently, the antifungal mechanism was investigated using fluorescence labeling, electron microscopy, reactive oxygen species (ROS) detection, and measurement of mitochondrial membrane potential and apoptosis. The impact of the engineered peptides on Candida albicans (C. albicans) biofilm and their potential application in the scratch keratomycosis model were investigated. ResultsThe antifungal activity of W4 was significantly enhanced by capping Gly at the N-terminus, resulting in a decrease in average activity from 11.86 μM to 6.25 μM (GW4) and an increase in TI values by 1.9-fold (TIGW4 = 40.99). Mechanistically, GW4 exerted its antifungal effect by disrupting the cellular membrane structure in C. albicans, forming pores and subsequent leakage of intracellular contents. Concurrently, it facilitated intracellular ROS accumulation while decreasing the mitochondrial membrane potential. Additionally, GW4 demonstrated an excellent ability to inhibit and eliminate biofilms of C. albicans. Notably, GW4 demonstrated significant therapeutic potential in a C. albicans-associated keratitis model. ConclusionCapping Gly at the N-terminus increased residue length while significantly enhancing the helical propensity of W4, thereby augmenting its antifungal activity. Our exploratory study demonstrated the potential strategies and avenues for optimizing the structure–function relationships of AFPs and developing highly effective antifungal drugs.

AlgU mediates hyperosmotic tolerance in Pseudomonas protegens SN15-2 by regulating membrane stability, ROS scavenging, and osmolyte synthesis.

Pseudomonas protegens can serve as an agricultural biocontrol agent. P. protegens often encounters hyperosmotic stress during industrial production and field application. The ability of P. protegens to withstand hyperosmotic stress is important for its application as a biocontrol agent. AlgU is a global regulator responsible for stress response and biocontrol ability. However, the specific regulatory role of AlgU in the hyperosmotic adaptation of P. protegens is poorly understood. In this study, we found that the AlgU mutation disrupted the hyperosmotic tolerance of P. protegens. Many genes and metabolites related to cell envelope formation were significantly downregulated in ΔalgU compared with that in the wild-type (WT) strain under hyperosmotic conditions, and we found that the algU mutation caused membrane integrity to be compromised and increased membrane permeability. Further experiments revealed that the cell envelope integrity protein TolA, which is regulated by AlgU, contributes to cell membrane stability and osmotic tolerance in P. protegens. In addition, several genes related to oxidative stress response were significantly downregulated in ΔalgU, and higher levels of intracellular reactive oxygen species were found in ΔalgU. Furthermore, we found that the synthesis of N-acetyl glutaminyl glutamine amide is directly regulated by AlgU and contributes to the hyperosmotic adaptation of P. protegens. This study revealed the mechanisms of AlgU's participation in osmotic tolerance in P. protegens, and it provides potential molecular targets for research on the hyperosmotic adaptation of P. protegens.IMPORTANCEIn this study, we found that the extracytoplasmic function sigma factor AlgU is essential for the survival of P. protegens under hyperosmotic conditions. We provided evidence supporting the roles of AlgU in influencing cell membrane stability, intracellular reactive oxygen species (ROS) accumulation, and dipeptide N-acetylglutaminylglutamine amide (NAGGN) synthesis in P. protegens under hyperosmotic conditions. Our findings revealed the mechanisms of AlgU's participation in hyperosmotic stress tolerance in P. protegens, and they provide potential molecular targets for research on the hyperosmotic adaptation of P. protegens, which is of value in improving the biocontrol ability of P. protegens.

Examining Hemin and its Derivatives: Induction of Heme-Oxygenase-1 Activity and Oxidative Stress in Breast Cancer Cells through Collaborative Experimental Analysis and Molecular Dynamics Simulations.

Hemin triggers intracellular reactive oxygen species (ROS) accumulation and enhances heme oxygenase-1 (HOX-1) activity, indicating its potential as an anticancer agent, though precise control of its intracellular levels is crucial. The study explores the impact of hemin and its derivatives, hemin-tyrosine, and hemin-styrene (H-Styr) conjugates on migration, HOX-1 expression, specific apoptosis markers, mitochondrial functions, and ROS generation in breast cancer cells. Molecular docking and dynamics simulations were used to understand the interactions among HOX-1, heme, and the compounds. Hemin outperforms its derivatives in inducing HOX-1 expression, exhibiting pro-oxidative effects and reducing cell migration. Molecular simulations show that heme binds favorably to HOX-1, followed by the other compounds, primarily through van der Waals and electrostatic forces. However, only van der Waals forces determine the H-Styr complexation. These interactions, influenced by metalloporphyrin characteristics, provide insights into HOX-1 regulation and ROS generation, potentially guiding the development of breast cancer therapies targeting oxidative stress.

ROS-responsive nanoparticle delivery of obeticholic acid mitigate primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a challenging cholestatic liver disease marked by progressive bile duct inflammation and fibrosis that has no FDA-approved therapy. Although obeticholic acid (OCA) has been sanctioned for PSC, its clinical utility in PSC is constrained by its potential hepatotoxicity. Here, we introduce a novel therapeutic construct consisting of OCA encapsulated within a reactive oxygen species (ROS)-responsive, biodegradable polymer, further cloaked with human placenta-derived mesenchymal stem cell (hP-MSC) membrane (MPPFTU@OCA). Using PSC patient-derived organoid models, we assessed its cellular uptake and cytotoxicity. Moreover, using a PSC mouse model induced by 3,5-diethoxycarbonyl-1,4-dihydro-collidine (DDC), we demonstrated that intravenous administration of MPPFTU@OCA not only improved cholestasis via the FXR-SHP pathway but also reduced macrophage infiltration and the accumulation of intracellular ROS, and alleviated mitochondria-induced apoptosis. Finally, we verified the ability of MPPFTU@OCA to inhibit mitochondrial ROS thereby alleviating apoptosis by measuring the mitochondrial adenosine triphosphate (ATP) concentration, ROS levels, and membrane potential (ΔΨm) using H2O2-stimulated PSC-derived organoids. These results illuminate the synergistic benefits of integrating an ROS-responsive biomimetic platform with OCA, offering a promising therapeutic avenue for PSC.

Injectable hydrogel encapsulating siMMP13 with anti-ROS and anti-apoptotic functions for osteoarthritis treatment

BackgroundOsteoarthritis (OA) is a degenerative joint disease characterized by the progressive degeneration of articular cartilage, leading to pain, stiffness, and loss of joint function. The pathogenesis of OA involves multiple factors, including increased intracellular reactive oxygen species (ROS), enhanced chondrocyte apoptosis, and disturbances in cartilage matrix metabolism. These processes contribute to the breakdown of the extracellular matrix (ECM) and the loss of cartilage integrity, ultimately resulting in joint damage and dysfunction. RNA interference (RNAi) therapy has emerged as a promising approach for the treatment of various diseases, including hATTR and acute hepatic porphyria. By harnessing the natural cellular machinery for gene silencing, RNAi allows for the specific inhibition of target genes involved in disease pathogenesis. In the context of OA, targeting key molecules such as matrix metalloproteinase-13 (MMP13), which plays a critical role in cartilage degradation, holds great therapeutic potential.ResultsIn this study, we developed an innovative therapeutic approach for OA using a combination of liposome-encapsulated siMMP13 and NG-Monomethyl-L-arginine Acetate (L-NMMA) to form an injectable hydrogel. The hydrogel served as a delivery vehicle for the siMMP13, allowing for sustained release and targeted delivery to the affected joint. Experiments conducted on destabilization of the medial meniscus (DMM) model mice demonstrated the therapeutic efficacy of this composite hydrogel. Treatment with the hydrogel significantly inhibited the degradation of cartilage matrix, as evidenced by histological analysis showing preserved cartilage structure and reduced loss of proteoglycans. Moreover, the hydrogel effectively suppressed intracellular ROS accumulation in chondrocytes, indicating its anti-oxidative properties. Furthermore, it attenuated chondrocyte apoptosis, as demonstrated by decreased levels of apoptotic markers.ConclusionIn summary, the injectable hydrogel containing siMMP13, endowed with anti-ROS and anti-apoptotic properties, may represent an effective therapeutic strategy for osteoarthritis in the future.

Inhibition of insulin degrading enzyme suppresses osteoclast hyperactivity via enhancing Nrf2-dependent antioxidant response in glucocorticoid-induced osteonecrosis of the femoral head

BackgroundOsteoclast hyperactivation due to the pathological overproduction of reactive oxygen species (ROS) stimulated by glucocorticoids (GCs) is one of the key drivers behind glucocorticoid-induced osteonecrosis of the femoral head (GIONFH). The insulin degrading enzyme (IDE), a conserved Zn2+ metallo-endopeptidase, facilitates the DNA binding of glucocorticoid receptor and plays a substantial role in steroid hormone-related signaling pathways. However, the potential role of IDE in the pathogenesis of GIONFH is yet undefined.MethodsIn this study, we employed network pharmacology and bioinformatics analysis to explore the impact of IDE inhibition on GIONFH with 6bK as an inhibitory agent. Further evidence was collected through in vitro osteoclastogenesis experiments and in vivo evaluations involving methylprednisolone (MPS)-induced GIONFH mouse model.ResultsEnrichment analysis indicated a potential role of 6bK in redox regulation amid GIONFH development. In vitro findings revealed that 6bK could attenuate GCs-stimulated overactivation of osteoclast differentiation by interfering with the transcription and expression of key osteoclastic genes (Traf6, Nfatc1, and Ctsk). The use of an H2DCFDA probe and subsequent WB assays introduced the inhibitory effects of 6bK on osteoclastogenesis, linked with the activation of the nuclear factor erythroid-derived 2-like 2 (Nrf2)-mediated antioxidant system. Furthermore, Micro-CT scans validated that 6bK could alleviate GIONFH in MPS-induced mouse models.ConclusionsOur findings suggest that 6bK suppresses osteoclast hyperactivity in GCs-rich environment. This is achieved by reducing the accumulation of intracellular ROS via promoting the Nrf2-mediated antioxidant system, thus implying that IDE could be a promising therapeutic target for GIONFH.

A nanoscale γ-cyclodextrin metal-organic framework loaded with eugenol (CMFE) for controlling F. graminearum on the wheat during harvest time

The loss of grains in the production chain caused huge waste worldwide, and the control of plant pathogenic fungi during harvest time is a critical solution to mitigate the damage. Eugenol, an important component of clove oil (Syzygium aromaticum L.), has antioxidant, antifungal, and other activities. In this study, the unstable eugenol was incorporated into the nanoscale γ-cyclodextrin metal-organic framework (γ-CD-MOF), a cubic porous structure synthesized by vapor diffusion method. The investigation of morphologies, functional groups, crystalline structures and weight losing behaviors demonstrated the inclusion complex prepared from γ-CD-MOF and eugenol (CMFE). Compared with the γ-CD loaded with eugenol (CE), CMFE exhibited an improved loading rate with 4.06 % (w/w). And CMFE enhanced the stability of its inner eugenol against degradation by light and air. Moreover, the CMFE demonstrated a significant anti-F. graminearum activity both in the medium and on the wheat grains. The inhibition rate reached 83.8 % at 8 mg/mL in vitro, while the growth of the hyphae was effectively restrained at 4 mg/g in vivo. CMFE could damage the mycelial cell wall and trigger intracellular reactive oxygen species (ROS) accumulation, thus exhibiting its anti-F. graminearum activity. Our results showed that the biocompatible CMFE would be an environment-friendly substitute to chemical fungicides for the prevention of fungal contamination caused by F. graminearum.

Sirt7 protects against vascular calcification via modulation of reactive oxygen species and senescence of vascular smooth muscle cells

Vascular calcification is frequently seen in patients with chronic kidney disease (CKD), and significantly increases cardiovascular mortality and morbidity. Sirt7, a NAD+-dependent histone deacetylases, plays a crucial role in cardiovascular disease. However, the role of Sirt7 in vascular calcification remains largely unknown. Using in vitro and in vivo models of vascular calcification, this study showed that Sirt7 expression was significantly reduced in calcified arteries from mice administered with high dose of vitamin D3 (vD3). We found that knockdown or inhibition of Sirt7 promoted vascular smooth muscle cell (VSMC), aortic ring and vascular calcification in mice, whereas overexpression of Sirt7 had opposite effects. Intriguingly, this protective effect of Sirt7 on vascular calcification is dependent on its deacetylase activity. Unexpectedly, Sirt7 did not alter the osteogenic transition of VSMCs. However, our RNA-seq and subsequent studies demonstrated that knockdown of Sirt7 in VSMCs resulted in increased intracellular reactive oxygen species (ROS) accumulation, and induced an Nrf-2 mediated oxidative stress response. Treatment with the ROS inhibitor N-acetylcysteine (NAC) significantly attenuated the inhibitory effect of Sirt7 on VSMC calcification. Furthermore, we found that knockdown of Sirt7 delayed cell cycle progression and accelerated cellular senescence of VSMCs. Taken together, our results indicate that Sirt7 regulates vascular calcification at least in part through modulation of ROS and cellular senescence of VSMCs. Sirt7 may be a potential therapeutic target for vascular calcification.

Disruption of Cell Membranes and Redox Homeostasis as an Antibacterial Mechanism of Dielectric Barrier Discharge Plasma against Fusarium oxysporum.

Direct barrier discharge (DBD) plasma is a potential antibacterial strategy for controlling Fusarium oxysporum (F. oxysporum) in the food industry. The aim of this study was to investigate the inhibitory effect and mechanism of action of DBD plasma on F. oxysporum. The result of the antibacterial effect curve shows that DBD plasma has a good inactivation effect on F. oxysporum. The DBD plasma treatment severely disrupted the cell membrane structure and resulted in the leakage of intracellular components. In addition, flow cytometry was used to observe intracellular reactive oxygen species (ROS) levels and mitochondrial membrane potential, and it was found that, after plasma treatment, intracellular ROS accumulation and mitochondrial damage were accompanied by a decrease in antioxidant enzyme activity. The results of free fatty acid metabolism indicate that the saturated fatty acid content increased and unsaturated fatty acid content decreased. Overall, the DBD plasma treatment led to the oxidation of unsaturated fatty acids, which altered the cell membrane fatty acid content, thereby inducing cell membrane damage. Meanwhile, DBD plasma-induced ROS penetrated the cell membrane and accumulated intracellularly, leading to the collapse of the antioxidant system and ultimately causing cell death. This study reveals the bactericidal effect and mechanism of the DBD treatment on F. oxysporum, which provides a possible strategy for the control of F. oxysporum.

Solar/ClO2 system inactivates fungal spores in drinking water: Synergy, efficiency and mechanisms

The risk of fungal pollution in drinking water has been paid attention. Solar/chlorine dioxide (ClO2) combined system is an environment-friendly, economical and efficient disinfection method, especially for countries and regions that are economically backward and still exposed to unsafe drinking water. In this paper, the kinetics, influencing factors, mechanism and regrowth potential of inactivated Aspergillus niger (A. niger) spores by solar/ClO2 were reported for the first time. The inactivation curve can be divided into three stages: instant inactivation within 1–2 min, slow linear inactivation and finally a tail. The synergistic factors produced by solar/ClO2 in terms of log reduction and maximum inactivation rate were 1.194 and 1.112, respectively. The inhibitory effect on the regrowth of A. niger spores inactivated by solar/ClO2 was also stronger than that by ClO2 alone. Strongly oxidizing reactive species produced by solar/ClO2 accelerated the accumulation of endogenic reactive oxygen species (ROS) caused by oxidation stress of A. niger spores, improving the inactivation ability of the system. The inactivation order of A. niger spores was: loss of culturability, accumulation of intracellular ROS, loss of membrane integrity, leakage of intracellular species and change of morphology. The inactivation performance of solar/ClO2 was better than solar/chlor(am)ine according to the comparison of inactivation efficiency and regrowth potential. Results also suggested that solar/ClO2 process was more suitable for the treatment of ground water sources.