Reduced Reactive Oxygen Species Accumulation Research Articles

A small heat shock protein GmHSP18.5a improves the male fertility restorability of cytoplasmic male sterility-based restorer line under high temperature stress in soybean

Small heat shock protein (sHSP) is involved in high temperature (HT) stress response. However, the function of sHSPs in regulating male fertility of soybean under HT stress remains largely unknown. Here, we identified a sHSP gene, GmHSP18.5a, which was responded to HT stress during flowering in cytoplasmic male sterility (CMS)-based restorer line of soybean. Moreover, GmHSFA6b turned out to directly activated the expression of GmHSP18.5a by binding to the heat shock cis-element in its promoter. Overexpression of GmHSP18.5a increased male fertility in transgenic Arabidopsis, soybean CMS-based restorer line and its hybrid F1 with CMS line under HT stress. Reactive oxygen species (ROS) content detection revealed that GmHSP18.5a promoted the ROS scavenging ability of Arabidopsis inflorescence and soybean flower bud under HT stress. Enzyme activity assay and gene expression analysis indicated that GmHS18.5a mainly increased the activity of antioxidant enzymes and the expression level of ROS metabolism-related genes under HT stress. Our results indicated that GmHSP18.5a improved the male fertility restorability of CMS-based restorer line in soybean by regulating ROS metabolic pathway and reducing ROS accumulation. Our findings not only revealed the molecular mechanism of sHSP regulating the male fertility of soybean under HT stress, but also provided a theoretical basis for creating strong restorer line with thermotolerance.

MG132, Attenuates the Retinal Vascular Injury Through the Upregulation of Nrf2 Expression.

Purpose: This study clarifies the beneficial effects of MG132, a proteasomal inhibitor, on retinal vascular injury mediated by diabetes-induced oxidative stress through nuclear factor erythroid 2-related factor 2 (Nrf2). Methods: Diabetic rats and control animals were randomly assigned to receive MG132 or vehicle for 24 weeks, and human retinal endothelial cells (HRECs) were incubated with normal or high glucose with or without MG132. 26S proteasome activity in the rat retinas or cultured HRECs was measured using Suc-LLVY-7-amido-4-methylcoumarin. NADPH-quinone oxidoreduc-tase (NQO1), heme oxygenase (HO)-1, kelch-like ECH-associated protein 1 (Keap1) and Nrf2 were examined by Western blotting and real-time reverse transcription polymerase chain reaction. Cell apoptosis is measured through flow cytometry assay, mitochondrial reactive oxygen species (ROS) production, and retinal vascular leakage were assayed using CM-H2DCFDA fluorescent probes and Evans blue, respectively. Results: MG132 significantly inhibited the activation of 26S proteasome induced by diabetes or elevated glucose, and subsequently increased the expression of Nrf2, NQO1, and HO-1, and further reduced ROS accumulation. These changes were associated with a decrease of diabetes-induced retinal vascular leakage and retinal capillary cell apoptosis. Conclusions: MG132 decreases diabetes-induced 26S proteasome activation and exerts protective effects against retinal microvascular dysfunction in diabetic rats in association with the alleviation of retinal oxidative stress mediated by Nrf2.

Salidroside inhibits renal ischemia/reperfusion injury‑induced ferroptosis by the PI3K/AKT signaling pathway.

Renal ischemia/reperfusion injury (RIRI) represents the principal factor underlying acute kidney injury (AKI), which primarily stems from cellular injuries and ferroptosis caused by reactive oxygen species (ROS). Salidroside (SA), an antioxidant natural ester, has been attributed with the potential to protect against RIRI. In the present study, rats received daily SA doses (1, 10, or 100 mg/kg) by gavage for 7 consecutive days before surgery. The results revealed aggravated renal injury in the RIRI group, which was effectively prevented by SA pretreatment (10 and 100 mg/kg), with the 1 mg/kg dosage demonstrating lesser efficacy. Additionally, the results indicated that SA pretreatment mitigated the RIRI-related upregulation of antioxidative superoxide dismutase. In vitro studies corroborated SA's ability to maintain hypoxia/reoxygenation-treated NRK cell viability, with the protective effect being observed at SA concentrations ≥1 µM and peaking at 100 µM. Furthermore, the results showed that SA safeguarded renal tubular epithelial cells from oxidative damage, reduced ROS accumulation, and inhibited ferroptosis via activation of the PI3K/AKT signaling pathway. Therefore, the results of the present study highlight the promising therapeutic potential of SA as an effective intervention for RIRI via targeting of PI3K/AKT signaling pathway-mediated anti-oxidative and anti-ferroptotic mechanisms.

CFTR potentiator ivacaftor protects against noise-induced hair cell loss by increasing Nrf2 and reducing oxidative stress

Over-production of reactive oxygen species (ROS) in the inner ear can be triggered by a variety of pathological events identified in animal models after traumatic noise exposure. Our previous research found that inhibition of the AMP-activated protein kinase alpha subunit (AMPKα) protects against noise-induced cochlear hair cell loss and hearing loss by reducing ROS accumulation. However, the molecular pathway through which AMPKα exerts its antioxidative effect is still unclear. In this study, we have investigated a potential target of AMPKα and ROS, cystic fibrosis transmembrane conductance regulator (CFTR), and the protective effect against noise-induced hair cell loss of an FDA-approved CFTR potentiator, ivacaftor, in FVB/NJ mice, mouse explant cultures, and HEI-OC1 cells. We found that noise exposure increases phosphorylation of CFTR at serine 737 (p-CFTR, S737), which reduces wildtype CFTR function, resulting in oxidative stress in cochlear sensory hair cells. Pretreatment with a single dose of ivacaftor maintains CFTR function by preventing noise-increased p-CFTR (S737). Furthermore, ivacaftor treatment increases nuclear factor E2-related factor 2 (Nrf2) expression, diminishes ROS formation, and attenuates noise-induced hair cell loss and hearing loss. Additionally, inhibition of noise-induced AMPKα activation by compound C also diminishes p-CFTR (S737) expression. In line with these in-vivo results, administration of hydrogen peroxide to cochlear explants or HEI-OC1 cells increases p-CFTR (S737) expression and induces sensory hair cell or HEI-OC1 cell damage, while application of ivacaftor halts these effects. Although ivacaftor increases Nrf2 expression and reduces ROS accumulation, cotreatment with ML385, an Nrf2 inhibitor, abolishes the protective effects of ivacaftor against hydrogen-peroxide-induced HEI-OC1 cell death. Our results indicate that noise-induced sensory hair cell damage is associated with p-CFTR. Ivacaftor has potential for treatment of noise-induced hearing loss by maintaining CFTR function and increasing Nrf2 expression for support of redox homeostasis in sensory hair cells.

The SbWRKY54–SbHKT2b transcriptional cascade confers cadmium stress tolerance in sorghum

In plants, high–affinity potassium transporters (HKTs) not only play a significant role in potassium transport but may also be important for the abiotic stress response. However, information regarding the response of HKTs to cadmium (Cd) stress is limited. Here, we focus on SbHKT2b, the expression of which is highly induced by Cd exposure. SbHKT2b overexpression reduced the accumulation of Cd and increased tolerance to Cd exposure, while SbHKT2b–RNA interference (RNAi) lines exhibited the opposite phenotype. In addition, the overexpression of SbHKT2b resulted in reduced reactive oxygen species (ROS) accumulation and enhanced ROS quenching capacity under Cd stress. Further analyses revealed that SbWRKY54 directly binds to the SbHKT2b promoter and upregulates its expression. Overall, the overexpression of SbWRKY54 decreased Cd and ROS accumulation in transgenic sorghum. Taken together, our results showed that SbWRKY54–SbHKT2b is an important Cd stress response pathway in sorghum.

Biomimetic Hyaluronic Acid-Based Brush Polymers Modulate Chondrocyte Homeostasis via ROS/Ca2+/TRPV4.

Bionic mimics using natural cartilage matrix molecules can modulate the corresponding metabolic activity by improving the microenvironment of chondrocytes. A bionic brush polymer, HA/PX, has been found to reverse the loss of cartilage extracellular matrix (ECM) and has promising applications in the clinical treatment of osteoarthritis (OA). However, the unknown bioremediation mechanism of HA/PX severely hinders its clinical translation. In OA, the massive loss of the ECM may be attributed to a decrease in transient receptor potential vanilloid 4 (TRPV4) activity, which affects reactive oxygen species (ROS) clearance and [Ca2+]i signaling, initiating downstream catabolic pathways. In this study, we investigated the bioremediation mechanism of HA/PX in a model of interleukin 1β (IL-1β)-induced inflammation. Through TRPV4, HA/PX reduced ROS accumulation in chondrocytes and enhanced [Ca2+]i signaling, reflecting a short-term protection capacity for chondrocytes. In addition, HA/PX balanced the metabolic homeostasis of chondrocytes via TRPV4, including promoting the secretion of type II collagen (Col-II) and aggrecan, the major components of the ECM, and reducing the expression of matrix metal-degrading enzyme (MMP-13), exerting long-term protective effects on chondrocytes. Molecular dynamics (MD) simulations showed that HA/PX could act as a TRPV4 activator. Our results suggest that HA/PX can regulate chondrocyte homeostasis via ROS/Ca2+/TRPV4, thereby improving cartilage regeneration. Because the ECM is a prevalent feature of various cell types, HA/PX holds promising potential for improving regeneration and disease modification for not only cartilage-related healthcare but many other tissues and diseases.

Antioxidant nanoemulsion loaded with latanoprost enables highly effective glaucoma treatment

Glaucoma is the third leading cause of blindness worldwide and is primarily characterized by elevated intraocular pressure (IOP). Common risk factors such as age, myopia, ocular trauma, and hypertension all increase the risk of elevated IOP. Prolonged high IOP not only causes physiological discomfort like headaches, but also directly damages retinal cells and leads to retinal ischemia, oxidative imbalance, and accumulation of reactive oxygen species (ROS) in the retina. This oxidative stress causes the oxidation of proteins and unsaturated lipids, leading to peroxide formation and exacerbating retinal damage. While current clinical treatments primarily target reducing IOP through medication or surgery, there are currently no effective methods to mitigate the retinal cell damage associated with glaucoma. To address this gap, we developed a novel nanoemulsion to co-delivery latanoprost and α-tocopherol (referred to as LA@VNE later) that prolongs ocular retention and enhances retinal permeability through localized administration. By encapsulating latanoprost, an IOP-lowering drug, and α-tocopherol, a potent antioxidant, we effectively reduced ROS accumulation (>1.5-fold in vitro and 2.5-fold in vivo), retinal ganglion cell (RGC) apoptosis (>9 fold), and inflammatory cell infiltration (>1.6 fold). Our approach showed strong biocompatibility and significant potential for clinical translation, providing a promising platform for the treatment of glaucoma.

ROS scavenging and immunoregulative EGCG@Cerium complex loaded in antibacterial polyethylene glycol-chitosan hydrogel dressing for skin wound healing.

The elevation of oxidative stress and inflammatory response after injury remains a substantial challenge that can deteriorate the wound microenvironment and compromise the success of wound healing. Herein, the assembly of naturally derived epigallocatechin-3-gallate (EGCG) and Cerium microscale complex (EGCG@Ce) was prepared as reactive oxygen species (ROS) scavenger, which was further loaded in antibacterial hydrogels as wound dressing. EGCG@Ce shows superior antioxidation capacity towards various ROS including free radical, O2- and H2O2 through superoxide dismutase-like or catalase-mimicking catalytic activity. Importantly, EGCG@Ce could provide mitochondrial protective effect against oxidative stress damages, reverse the polarization of M1 macrophages and reduce the secretion of pro-inflammatory cytokines. Furtherly, EGCG@Ce was loaded into the PEG-chitosan hydrogel with dynamic, porous, injectable and antibacterial properties as wound dressing, which accelerated the regeneration of both epidermal layer and dermis, resulting in improved healing process of full-thickness skin wounds in vivo. Mechanistically, EGCG@Ce re-shaped the detrimental tissue microenvironment and augmented the pro-reparative response through reducing ROS accumulation, alleviating inflammatory response, enhancing the M2 macrophage polarization and angiogenesis. Collectively, antioxidative and immunomodulatory metal-organic complex-loaded hydrogel is a promising multifunctional dressing for the repair and regeneration of cutaneous wounds without additional drugs, exogenous cytokines, or cells. STATEMENT OF SIGNIFICANCE: (1) We reported an effective antioxidant through self-assembly coordination of EGCG and Cerium for managing the inflammatory microenvironment at the wound site, which not only showed high catalytic capacity towards multiple ROS, but also could provide mitochondrial protective effect against oxidative stress damage, reverse the polarization of M1 macrophages and downregulate pro-inflammatory cytokines. EGCG@Ce was further loaded into porous and bactericidal PEG-chitosan (PEG-CS) hydrogel as a versatile wound dressing, which accelerated wound healing and angiogenesis. (2) The applicability of alleviating sustainable inflammation and regulating macrophage polarization through ROS scavenging is a promising strategy for tissue repair and regeneration without additional drugs, cytokines, or cells.

High CO2 facilitates fatty acid biosynthesis and mitigates cellular oxidative stress caused by CAC2 dysfunction in Arabidopsis.

Increasing concentration of CO2 has significant impacts on many biological processes in plants, and its impact is closely associated with changes in the ratio of photosynthesis to photorespiration. Studies have reported that high CO2 can promote carbon fixing and alleviate plant oxidative damage in response to environmental stresses. However, the effect of high CO2 on fatty acid (FA) metabolism and cellular redox balance in FA-deficient plants is rarely reported. In this study, we identified a high-CO2 -requiring mutant cac2 through forward genetic screening. CAC2 encodes biotin carboxylase, which is one of the subunits of plastid acetyl-CoA carboxylase and participates in de novo FA biosynthesis. Null mutation of CAC2 is embryonic lethal. A point mutation of CAC2 in cac2 mutants produces severe defects in chloroplast development, plant growth and photosynthetic performance. These morphological and physiological defects were largely absent under high CO2 conditions. Metabolite analyses showed that FA contents in cac2-1 leaves were decreased, while photorespiratory metabolites, such as glycine and glycolate, did not significantly change. Meanwhile, cac2 exhibited higher reactive oxygen species (ROS) levels and mRNA expression of stress-responsive genes than the wild-type, indicating that cac2 plants may suffer oxidative stress under ambient CO2 conditions. Elevated CO2 significantly increased FA contents, especially C18:3-FA, and reduced ROS accumulation in cac2-1 leaves. We propose that stress mitigation by high CO2 in cac2 could be due to increased FA levels by promoting carbon assimilation, and the prevention of over-reduction due to decreased photorespiration.

Glucagon-like peptide-1 receptor agonist, semaglutide attenuates chronic liver disease-induced skeletal muscle atrophy in diabetic mice

A glucagon-like peptide-1 receptor agonist (GLP-1RA) has recently been established as a pharmacological option for the treatment of type 2 diabetes. Recent studies have demonstrated the molecular role of GLP-1R in skeletal muscle homeostasis; however, the therapeutic efficacy of semaglutide, a GLP-1RA, on skeletal muscle atrophy in chronic liver disease (CLD) under diabetic conditions remains unclear. In the present study, semaglutide effectively inhibited psoas muscle atrophy and suppressed declines in grip strength in a diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet-fed diabetic KK-Ay mouse model. Moreover, semaglutide inhibited ubiquitin-proteosome-mediated skeletal muscle proteolysis and promoted myogenesis in palmitic acid (PA)-stimulated C2C12 murine myocytes. Mechanistically, this effect of semaglutide on skeletal muscle atrophy was mediated by multiple functional pathways. First, semaglutide protected against hepatic injury in mice accompanied by increased production of insulin-like growth factor 1 and reduced accumulation of reactive oxygen species (ROS). These effects were associated with decreased proinflammatory cytokines and ROS accumulation, leading to the suppression of ubiquitin-proteosome muscle degradation. Moreover, semaglutide inhibited the amino acid starvation-related stress signaling that was activated under chronic liver injury, resulting in the recovery of the mammalian target of rapamycin activity in the skeletal muscle of DDC-diet fed KK-Ay mice. Second, semaglutide improved skeletal muscle atrophy by directly stimulating GLP-1R in myocytes. Semaglutide induced cAMP-mediated activation of PKA and AKT, enhanced mitochondrial biogenesis, and reduced ROS accumulation, thereby resulting in inhibition of NF-κB/myostatin-mediated ubiquitin-proteosome degradation and the augmentation of heat-shock factor-1-mediated myogenesis. Collectively, semaglutide may have potential as a new therapeutic strategy for CLD-related skeletal muscle wasting.

Extracellular arginine availability modulates eIF2α O-GlcNAcylation and heme oxygenase 1 translation for cellular homeostasis

BackgroundNutrient limitations often lead to metabolic stress during cancer initiation and progression. To combat this stress, the enzyme heme oxygenase 1 (HMOX1, commonly known as HO-1) is thought to play a key role as an antioxidant. However, there is a discrepancy between the level of HO-1 mRNA and its protein, particularly in cells under stress. O-linked β-N-acetylglucosamine (O-GlcNAc) modification of proteins (O-GlcNAcylation) is a recently discovered cellular signaling mechanism that rivals phosphorylation in many proteins, including eukaryote translation initiation factors (eIFs). The mechanism by which eIF2α O-GlcNAcylation regulates translation of HO-1 during extracellular arginine shortage (ArgS) remains unclear.MethodsWe used mass spectrometry to study the relationship between O-GlcNAcylation and Arg availability in breast cancer BT-549 cells. We validated eIF2α O-GlcNAcylation through site-specific mutagenesis and azido sugar N-azidoacetylglucosamine-tetraacylated labeling. We then evaluated the effect of eIF2α O-GlcNAcylation on cell recovery, migration, accumulation of reactive oxygen species (ROS), and metabolic labeling during protein synthesis under different Arg conditions.ResultsOur research identified eIF2α, eIF2β, and eIF2γ, as key O-GlcNAcylation targets in the absence of Arg. We found that O-GlcNAcylation of eIF2α plays a crucial role in regulating antioxidant defense by suppressing the translation of the enzyme HO-1 during Arg limitation. Our study showed that O-GlcNAcylation of eIF2α at specific sites suppresses HO-1 translation despite high levels of HMOX1 transcription. We also found that eliminating eIF2α O-GlcNAcylation through site-specific mutagenesis improves cell recovery, migration, and reduces ROS accumulation by restoring HO-1 translation. However, the level of the metabolic stress effector ATF4 is not affected by eIF2α O-GlcNAcylation under these conditions.ConclusionsOverall, this study provides new insights into how ArgS fine-tunes the control of translation initiation and antioxidant defense through eIF2α O-GlcNAcylation, which has potential biological and clinical implications.

Salicylic acid treatment delayed the browning development in the pericarp of fresh longan by regulating the metabolisms of ROS and membrane lipid

Longans is popular among consumers because of its rich nutritional value, but it is prone to pericarp browning as it is harvested in the high-temperature season. This work was to investigate the effects of salicylic acid (SA) on the metabolisms of reactive oxygen species (ROS) and membrane lipid and their relationship with pericarp browning of postharvest longans. ‘Fuyan’ longans were soaked in the solution of 0.3 g L-1 SA for 5 min, then stockpiled at 28 °C. The results showed that, the pericarp browning index in SA-treated fruit was 42% lower than that in the control fruit at day 5 of storage. Meanwhile, SA treatment reduced the damage severity of cell membrane structure, and maintained a low level of cell membrane permeability, which was 25% lower than that in the control fruit at day 5 of storage. Additionally, compared to the control fruit, SA-treated longans displayed higher levels of pericarp L*, flavonoid, chlorophyll, carotenoid, total phenolics, and anthocyanin, higher activities of pericarp superoxide dismutase, catalase, and ascorbate peroxidase, higher values of pericarp reducing power and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability, and higher amounts of pericarp ascorbic acid and glutathione, but lower levels of pericarp ROS and malondialdehyde. Moreover, SA-treated samples exhibited lower activities of pericarp phospholipase, lipase, and lipoxygenase, lower levels of pericarp phosphatidic acid and saturated fatty acids (SFA), but higher values of pericarp phosphatidylcholine, phosphatidylinositol, and unsaturated fatty acids (USFA), higher index of USFA, and higher ratio of USFA to SFA. These findings corroborated that SA delayed-browning occurrence in the pericarp of fresh longans was because SA enhanced the capacity to remove ROS, and reduced ROS accumulation and the membrane lipid degradation, thus maintaining the cellular membrane structure, reducing the degradation of pigments, and allowing the fresh longans to maintain a better appearance. Consequently, SA could be an effective means for suppressing pericarp browning and improving the commercial value of fresh longans.

Alpha-ketoglutarate supplementation ameliorates ovarian reserve and oocyte quality decline with aging in mice

Assisted reproductive technology is widely accepted as an effective treatment to improve female fertility, but the decline of aging oocyte quality remains an important factor in the decrease of female fecundity. However, the effective strategies for improving oocyte aging are still not well understood. In the study, we demonstrated that ROS content and abnormal spindle proportion were increased and mitochondrial membrane potential was decreased in aging oocytes. However, supplementation of α-ketoglutarate (α-KG), an immediate metabolite in the tricarboxylic acid cycle (TCA), for 4 months to aging mice, significantly increased the ovarian reserve showed by more follicle numbers observed. In addition, the oocyte quality was significantly improved, as demonstrated by reduced fragmentation rate and decreased reactive oxygen species (ROS) levels, in addition to a lower rate of abnormal spindle assembly, thereby improving the mitochondrial membrane potential. Consistent with the in vivo data, α-KG administration also improved the post-ovulated aging oocyte quality and early embryonic development by improving mitochondrial functions and reducing ROS accumulation and abnormal spindle assembly. Our data revealed that α-KG supplementation might be an effective strategy to improve the quality of aging oocytes in vivo or in vitro.

TaBAS1 encoding a typical 2-Cys peroxiredoxin enhances salt tolerance in wheat.

Efficient antioxidant enzymatic system contributes to salt tolerance of plants via avoiding ROS over-accumulation. Peroxiredoxins are crucial components of the reactive oxygen species (ROS) scavenging machinery in plant cells, but whether they offer salt tolerance with potential for germplasm improvement has not been well addressed in wheat. In this work, we confirmed the role of a wheat 2-Cys peroxiredoxin gene TaBAS1 that was identified through the proteomic analysis. TaBAS1 overexpression enhanced the salt tolerance of wheat at both germination and seedling stages. TaBAS1 overexpression enhanced the tolerance to oxidative stress, promoted the activities of ROS scavenging enzymes, and reduced ROS accumulation under salt stress. TaBAS1 overexpression promoted the activity of ROS production associated NADPH oxidase, and the inhibition of NADPH oxidase activity abolished the role of TaBAS1 in salt and oxidative tolerance. Moreover, the inhibition of NADPH-thioredoxin reductase C activity erased the performance of TaBAS1 in the tolerance to salt and oxidative stress. The ectopic expression of TaBAS1 in Arabidopsis exhibited the same performance, showing the conserved role of 2-Cys peroxiredoxins in salt tolerance in plants. TaBAS1 overexpression enhanced the grain yield of wheat under salt stress but not the control condition, not imposing the trade-offs between yield and tolerance. Thus, TaBAS1 could be used for molecular breeding of wheat with superior salt tolerance.

Loureirin C inhibits ferroptosis after cerebral ischemia reperfusion through regulation of the Nrf2 pathway in mice

BackgroundIschemic stroke (IS) is considered as a serious cerebral vascular disease. Ferroptosis is a novel type of regulated cell death (RCD), that closely related to the occurrence and progress of IS. Loureirin C, a type of dihydrochalcone compound derived from the Chinese Dragon's blood (CDB). The effective components extracted from CDB have shown neuroprotective effects in ischemia reperfusion models. However, the role of Loureirin C in mice after IS is not well understood. Thus, it is worth to identify the effect and mechanism of Loureirin C on IS. PurposeThe present research aims to prove the existence of ferroptosis in IS and explore whether Loureirin C can inhibit ferroptosis by regulating nuclear factor E2 related factor 2 (Nrf2) pathway in mice and exert neuroprotective effects on IS models. MethodsMiddle cerebral artery occlusion and reperfusion (MCAO/R) model was established to evaluate the occurrence of ferroptosis and the potential Loureirin C brain-protective effect in vivo. The analysis of free iron, glutamate content, reactive oxygen species (ROS) and lipid peroxidation levels, along with transmission electron microscope (TEM) was applied to prove the existence of ferroptosis. The function of Loureirin C on Nrf2 nuclear translocation was verified by immunofluorescence staining. In vitro, primary neurons and SH-SY5Y cells were processed with Loureirin C after oxygen and glucose deprivation-reperfusion (OGD/R). ELISA kits, western blotting, co-immunoprecipitation (Co-IP) analysis, immunofluorescence, and quantitative real-time PCR were devoted to proving the neuroprotective effects of Loureirin C on IS via regulating ferroptosis and Nrf2 pathways. ResultsThe results showed that Loureirin C not only dramatically alleviated brain injury and inhibited neurons ferroptosis in mice after MCAO/R, but also dose-dependently reduce ROS accumulation in ferroptosis after OGD/R. Further, Loureirin C inhibits ferroptosis by activating Nrf2 pathway, and promoting nuclear translocation of Nrf2. Besides, Loureirin C increases heme oxygenase 1 (HO-1), quinone oxidoreductase 1 (NQO1) and glutathione peroxidase 4 (GPX4) content after IS. Intriguingly, the anti-ferroptosis effect of Loureirin C is weakened by Nrf2 knockdown. ConclusionOur discoveries first revealed that the inhibitory action of Loureirin C on ferroptosis may greatly depend on its adjusting effect on the Nrf2 pathway, suggesting that Loureirin C could act as a novel anti-ferroptosis candidate and play a therapeutic role in IS. These novel discoveries on the role of Loureirin C on IS models reveal an innovative method that may contribute to neuroprotection for the prevention of IS.

5,7-Dihydroxy-4-methylcoumarin modulates the JNK/FoxO1 signaling pathway to attenuate cisplatin-induced ototoxicity by suppressing oxidative stress and apoptosis in vitro

5,7-Dihydroxy-4-methylcoumarin (D4M) is attributed to free radical scavenging effects, with wide application for anti-oxidation. This work aimed to assess D4M's impact on cisplatin-induced ototoxicity. The cell viability was estimated with CCK-8 assay. Apoptosis was detected by the Annexin V-FITC and PI assay. The reactive oxygen species (ROS) level was determined by MitoSOX-Red and CellROX-Green probes. Mitochondrial membrane potential was analyzed with TMRM staining. Immunofluorescence was utilized for hair cells and spiral ganglion neuron detection. Apoptosis-associated proteins were assessed by cleaved caspase-3 and TUNEL staining. These results showed that D4M pretreatment protected hair cells from cisplatin-induced damage, increased cell viability, and decreased apoptosis in House Ear Institute-Organ of Corti1 (HEI-OC1) cells and neonatal mouse cochlear explants. D4M significantly inhibited cisplatin-induced mitochondrial apoptosis and reduced ROS accumulation. In addition, the protective effect of D4M on cisplatin-induced ototoxicity was also confirmed in cochlear hair cells and spiral ganglion neurons in neonatal mice. Mechanistic studies showed that D4M markedly downregulated p-JNK and elevated the expression ratio of p-FoxO1/FoxO1, thereby reducing cisplatin-induced caspase-dependent apoptosis. Meanwhile, D4M-related protection of HEI-OC1 cells was significantly blunted by JNK signaling induction with anisomycin. This study supports the possibility that D4M may be used as a new compound to prevent cisplatin-related hearing loss.

L-Ascorbic Acid 2-Phosphate Attenuates Methylmercury-Induced Apoptosis by Inhibiting Reactive Oxygen Species Accumulation and DNA Damage in Human SH-SY5Y Cells

Methylmercury (MeHg) is a toxin that causes severe neuronal oxidative damage. As vitamin C is an antioxidant well-known to protect neurons from oxidative damage, our goal was to elucidate its protective mechanism against MeHg-induced oxidative stress in human neuroblastomas (SHSY5Y). We treated cells with MeHg, L-ascorbic acid 2-phosphate (AA2P), or both, and used MTT, flow cytometry, and Western blot analyses to assess cell damage. We found that MeHg significantly decreased the survival rate of SH-SY5Y cells in a time- and dose-dependent manner, increased apoptosis, downregulated PAR and PARP1 expression, and upregulated AIF, Cyto C, and cleaved Caspase-3 expression. A time course study showed that MeHg increased reactive oxygen species (ROS) accumulation; enhanced apoptosis; increased DNA damage; upregulated expression ofγH2A.X, KU70, 67 and 57 kDa AIF, CytoC, and cleaved Caspase-3; and downregulated expression of 116 kDa PARP1, PAR, BRAC1, and Rad51. Supplementation with AA2P significantly increased cell viability and decreased intrinsic ROS accumulation. It also reduced ROS accumulation in cells treated with MeHg and decreased MeHg-induced apoptosis. Furthermore, AA2P conversely regulated gene expression compared to MeHg. Collectively, we demonstrate that AA2P attenuates MeHg-induced apoptosis by alleviating ROS-mediated DNA damage and is a potential treatment for MeHg neurotoxicity.

Assessment of the Cadmium and Copper Phytoremediation Potential of the Lobularia maritima Thioredoxin 2 Gene Using Genetically Engineered Tobacco

Rapid global modernization, urbanization, and industrialization have accelerated the release of heavy metals, causing soil pollution. These highly noxious environmental pollutants induce oxidative stress in plants via stimulation of the production of reactive oxygen species (ROS). Thioredoxin (Trxs) is a highly conserved disulfide reductase that plays a crucial role in intracellular redox homeostasis in both eukaryotes and prokaryotes. Herein, the presence of heavy metals highly upregulated LmTrxh2 transcription in Lobularia maritima seedlings and its overexpression-conferred tolerance to Cd, Cu, Mn, and Zn in Saccharomyces cerevisiae. In addition, LmTrxh2-overexpressing tobacco plants had higher seedling survival rates than non-transgenic plants (NT), with enhanced root length and biomass production and reduced ROS accumulation, following Cd and Cu stress. These plants also accumulated more Cd, Cu, and Mn than the NT plants. Moreover, LmTrxh2 overexpression stimulated the transcription of genes encoding metallothioneins (Met-1, Met-2, Met-3, and Met-4), a copper transport protein, a Snakin/GASA protein (Snakin-2), and ROS-scavenging enzymes (SOD, APX1, and CAT), which might contribute to heavy metal tolerance in tobacco plants. These results suggest that LmTrxh2 overexpression helps to improve heavy metal tolerance by stimulating antioxidant capacities and the expression of several stress-responsive genes in plants.

Nitric Oxide Made a Major Contribution to the Improvement of Quality in Button Mushrooms (Agaricus bisporus) by the Combined Treatment of Nitric Oxide with 1-MCP.

Browning is one of the major effects of shelf-life responsible for the reduction in the commercial value of the button mushrooms (Agaricus bisporus). In this study, the individual and the combined effects of exogenous sodium nitroprusside (SNP, a nitric oxide donor) and 1-methylcyclopropene (1-MCP) on the quality of button mushrooms were evaluated. The results demonstrated that mushrooms treated with SNP+1-MCP promoted reactive oxygen species (ROS) metabolism thereby protecting cell membrane integrity, hindering polyphenol oxidase (PPO) binding to phenolic compounds, and downregulating the PPO activity. In addition, the SNP+1-MCP treatment effectively maintained quality (firmness, color, total phenol, and flavonoid) and mitigated oxidative damage by reducing ROS accumulation and malondialdehyde production through the stimulation of the antioxidant enzymes activities and the enhancement of ascorbic acid (AsA) and glutathione (GSH) contents. Moreover, the correlation analysis validated the above results. The SNP+1-MCP treatment was observed to be more prominent on maintaining quality than the individual effects of SNP followed by 1-MCP, suggesting that the combination of NO and 1-MCP had synergistic effects in retarding button mushrooms senescence, and NO signaling molecules might be predominant in the synergy.

Glutathione peroxidase 2 overexpression promotes malignant progression and cisplatin resistance of KRAS‑mutated lung cancer cells.

Kirsten rat sarcoma viral oncogene homolog (KRAS) aberrations frequently occur in patients with lung cancer. Oncogenic KRAS is characterized by excessive reactive oxygen species (ROS) accumulation, thus, ROS detoxification may contribute to KRAS-driven lung tumorigenesis. In the present study, the influence of glutathione peroxidase 2 (GPX2) on malignant progression and cisplatin resistance of KRAS-driven lung cancer was explored. The RNA sequencing data from TCGA lung cancer samples and GEO database were downloaded and analyzed. The effects of GPX2 on KRAS-driven lung tumorigenesis were evaluated by western blotting, cell viability assay, soft agar assay, Transwell assay, tumor xenograft model, flow cytometry, BrdU incorporation assay, transcriptome RNA sequencing, luciferase reporter assay and RNA immunoprecipitation. In the present study, GPX2 was upregulated in patients with non-small cell lung carcinoma (NSCLC), and positively correlated with poor overall survival. Ectopic GPX2 expression facilitated malignant progression of KRASG12C-transformed BEAS-2B cells. Moreover, GPX2 overexpression promoted growth, migration, invasion, tumor xenograft growth and cisplatin resistance of KRAS-mutated NSCLC cells, while GPX2 knockdown exhibited the opposite effects. GPX2 overexpression reduced ROS accumulation and increased matrix metalloproteinase-1 (MMP1) expression in KRAS-mutated NSCLC cells. In addition, GPX2 was directly targeted by miR-325-3p, while MMP1 knockdown or miR-325-3p overexpression partially abrogated the effects of GPX2 in NSCLC cells. In conclusion, the results indicated that GPX2 facilitated malignant progression and cisplatin resistance of KRAS-driven lung cancer, and inhibition of GPX2 may be a feasible strategy for lung cancer treatment, particularly in patients with active KRAS mutations.