Excessive Reactive Oxygen Species Research Articles

Activatable theranostic nanoprobes for Fluorescence/MR imaging and microenvironment remodeling of early cartilage degeneration

Osteoarthritis (OA) is a degenerative joint disease of the knee joint, suffering from the limited therapeutic effect and serious side effects. Unfortunately, there are currently rarely available materials to fundamentally delay and monitor OA progression. The OA microenvironment, including excessive inflammation, matrix metalloproteinases (MMPs), oxidative stress, and reactive oxygen species (ROS), play a crucial role in the pathogenesis of OA. Utilizing and remodeling OA microenvironment may be an effective strategy for the diagnosis and treatment of OA. This work developed an intelligent responsive nanoprobe, Gd-HMPB@SMT@MMP (GHPSM) by encapsulating S-methylisothiourea (SMT) loaded mesoporous Prussian Blue (Gd-HMPB) with Tetramethyl Rhodamine (TAMRA) labeled MMP-13 peptide (MMP-13-TAMRA) for this aim. GHPSM displayed enhanced accumulation in OA cartilage site due to the decrease in the content of negatively charged aminoglycans (GAGs) in early degenerative articular cartilage and activated fluorescence signal as well as SMT controlled release due to the cleavage of MMP-13-TAMRA from GHPSM by overexpressed MMP-13 matrix protease in OA microenvironment. Furthermore, integrating the function of SMT and PB nanozyme, GHPSM reshaped the OA microenvironment by reducing the release of ROS and inflammatory factors (TNF-α, IL-6, iNOS), increasing the expression of intermediate structural proteins (COL2 and Aggrescan), thereby reducing cartilage degradation and chondrocyte apoptosis, ultimately delaying the development of OA. The progressions of early OA disease after different treatments were successfully tracked based on fluorescence/MR imaging with X-ray imaging of knee joint for comparation. These findings highlight the potentials of GHPSM in monitoring the status of cartilage in real-time and delay OA progression by reshaping the OA microenvironment, providing novel ideas for future research in OA diagnosis and treatment.

Elevated Serum Xanthine Oxidase and Its Correlation with Antioxidant Status in Patients with Parkinson's Disease.

Parkinson's disease (PD) is a neurodegenerative movement disorder associated with a loss of dopamine neurons in the substantia nigra. The diagnosis of PD is sensitive since it shows clinical features that are common with other neurodegenerative diseases. In addition, most symptoms arise at the late stage of the disease, where most dopaminergic neurons are already damaged. Several studies reported that oxidative stress is a key modulator in the development of PD. This condition occurs due to excess reactive oxygen species (ROS) production in the cellular system and the incapability of antioxidants to neutralize it. In this study, we focused on the pathology of PD by measuring serum xanthine oxidase (XO) activity, which is an enzyme that generates ROS. Interestingly, the serum XO activity of patients with PD was markedly upregulated compared to patients with other neurological diseases (ONDs) as a control. Moreover, serum XO activity in patients with PD showed a significant correlation with the disease severity based on the Hoehn and Yahr (HY) stages. The investigation of antioxidant status also revealed that serum uric acid levels were significantly lower in the severe group (HY ≥ 3) than in the ONDs group. Together, these results suggest that XO activity may contribute to the development of PD and might potentially be a biomarker for determining disease severity in patients with PD.

Potential New Therapies "ROS-Based" in CLL: An Innovative Paradigm in the Induction of Tumor Cell Apoptosis.

Chronic lymphocytic leukemia, in spite of recent advancements, is still an incurable disease; the majority of patients eventually acquire resistance to treatment through relapses. In all subtypes of chronic lymphocytic leukemia, the disruption of normal B-cell homeostasis is thought to be mostly caused by the absence of apoptosis. Consequently, apoptosis induction is crucial to the management of this illness. Damaged biological components can accumulate as a result of the oxidation of intracellular lipids, proteins, and DNA by reactive oxygen species. It is possible that cancer cells are more susceptible to apoptosis because of their increased production of reactive oxygen species. An excess of reactive oxygen species can lead to oxidative stress, which can harm biological elements like DNA and trigger apoptotic pathways that cause planned cell death. In order to upset the balance of oxidative stress in cells, recent therapeutic treatments in chronic lymphocytic leukemia have focused on either producing reactive oxygen species or inhibiting it. Examples include targets created in the field of nanomedicine, natural extracts and nutraceuticals, tailored therapy using biomarkers, and metabolic targets. Current developments in the complex connection between apoptosis, particularly ferroptosis and its involvement in epigenomics and alterations, have created a new paradigm.

3D Cryo‐Printed Hierarchical Porous Scaffolds Harmonized with Hybrid Nanozymes for Combinatorial Mitochondrial Therapy: Enhanced Diabetic Bone Regeneration via Micromilieu Remodeling

AbstractRegeneration of bone defects in diabetic patients has always been a significant challenge in clinical treatment. The pathologic diabetic micromilieu, characterized by mitochondrial dysfunction, excessive reactive oxygen species (ROS) accumulation, cellular senescence, and chronic inflammation, compromises innate bone healing capacity. 3D cryo‐printing technology is utilized in bone tissue engineering to fabricate hierarchical porous scaffolds that promote a conducive microenvironment for cellular adhesion, migration, proliferation, and nutrient exchange. Nanozymes are used as synthetic mimics of natural enzymes to scavenge ROS, addressing the limitations of natural antioxidative enzymes. To remodel the diabetic bone regeneration micromilieu, a 3D cryo‐printed polyaryletherketone with carboxyl groups (PAEK‐COOH) and 45S5 bioactive glass (BG) hierarchical porous scaffold (PBG scaffold), harmonized with hybrid nanozymes comprising SS31‐enhanced manganese dioxide (MnO2)‐ferritin biomimetic nanozyme (MF@S nanozyme), is developed for combinatorial mitochondrial therapy. The MF@S nanozyme specifically targets mitochondria to enhance mitochondrial function, scavenge ROS accumulated in mitochondria, and suppress mitochondrial ROS (mtROS) production, and thus rejuvenate aging cells, regulate macrophage polarization, and modulate differentiation of osteoblasts and osteoclasts. This 3D cryo‐printed PBG‐MF@S hierarchical porous scaffold combines with a combinatorial mitochondrial therapy system to remodel the diabetic micromilieu and presents a promising therapeutic approach for the regeneration of bone defects in diabetes.

Salt Tolerance Assessment in Triticum Aestivum and Triticum Durum.

Salt stress is a multicomponent phenomenon; it includes many processes that directly or indirectly affect the plant. Attempts have been made to comprehensively consider the processes of salt stress in plants Triticum aestivum (variety Orenburgskaya 22) and Triticum durum (variety Zolotaya). The study used methods of light and fluorescence microscopy, methods of immunofluorodetection, expression of DNA methyltransferase genes, genes of the ion transporter and superoxide dismutase families, as well as biochemical determination of total antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) reagent. According to morphometric indicators, the Orenburgskaya 22 variety showed greater tolerance to the action of 150 mM NaCl than the Zolotaya variety. The level of expression of genes of the HKT ion transporter family in the Orenburgskaya 22 variety is higher than in the Zolotaya variety. It was found that the expression of the DNA methyltransferase gene DRM2.1, which post-translationally methylates cytosine residues, is 22.3 times higher in Zolotaya compared to Orenburg 22 when exposed to salt. The accumulation of toxic ions is accompanied by an increase in reactive oxygen species (ROS) and increased damage to root tissue, especially in the Zolotaya variety. Using fluorescence microscopy using the Carboxy-H2DFF marker in the Orenburgskaya 22 variety at high NaCl concentrations, the highest fluorescence intensity was determined in the cap zone; in the Zolotaya variety-in the zones of the cap and root meristem. Excess ROS is more successfully removed in the Orenburgskaya 22 variety, which has a higher level of antioxidant activity (AOA), as well as the level of expression of the Cu/ZnSOD and MnSOD superoxide dismutase genes. Using programmed cell death (PCD) markers based on the release of cytochrome c from mitochondria into the cytoplasm, DNA breakage and the release of phosphatidylserine from mitochondria, the degree of damage to root cells was assessed in both wheat varieties. It has been proven that wheat cell death occurs through the mitochondrial pathway. It was noted that the salt-sensitive variety Zolotaya had a significant number of necrotic cells. Based on the data obtained, it was concluded that the Orenburgskaya 22 variety exhibits greater resistance to salinity than the Zolotaya variety. These data may be of practical importance for enhancing protective mechanisms under abiotic stress.

Self-responsive H2-releasing microneedle patch temporally adapts to the sequential microenvironment requirements for optimal diabetic wound healing

Oxidative stress regulation and synchronized promotion of angiogenesis are critical factors in the healing process of diabetic wounds. However, existing research often fails to fully consider the dynamic interplay between these two biological processes and their time-dependent roles in diabetic wound healing. This study innovatively introduces a novel hydrogen (H2)-releasing microneedle patch capable of precisely controlling the regulation of oxidative stress and the promotion of angiogenesis through a bidirectional responsive mechanism of microneedles and backing layers. Specifically, we employ ammonia borane (AB)-loaded mesoporous silica nanoparticles (MSN) as a source of H2, combined with polyvinyl pyrrolidone (PVP) to fabricate microneedles. This design effectively clears excessive reactive oxygen species (ROS) in deep tissues and promotes the M2 polarization of macrophages. Concurrently, we utilize cobalt-adsorbed graphene oxide (GO/Co2+) mixed with polyvinyl alcohol (PVA) to prepare backing layers, which not only release Co2+ upon the reduction of oxygen-containing functional groups in GO by H2 diffused from deep tissues to synergize with H2 for enhanced vascularization, but also endow the microneedle patch with near-infrared (NIR) light-responsive antimicrobial properties, crucial for managing diabetic infected wounds. Through this innovative dual-action mechanism, our research significantly accelerates the healing process of infected wounds in a diabetic mouse model. Moreover, single-cell sequencing results further confirm the pivotal role of H2 in regulating oxidative stress, promoting macrophage M2 polarization, and stimulating angiogenesis. These results not only showcase the unique features of our microneedle patch but also offer new perspectives and therapeutic strategies for the treatment of diabetic wounds.

Kaempferol as an Alternative Cryosupplement for Bovine Spermatozoa: Cytoprotective and Membrane-Stabilizing Effects.

Kaempferol (KAE) is a natural flavonoid with powerful reactive oxygen species (ROS) scavenging properties and beneficial effects on ex vivo sperm functionality. In this paper, we studied the ability of KAE to prevent or ameliorate structural, functional or oxidative damage to frozen-thawed bovine spermatozoa. The analysis focused on conventional sperm quality characteristics prior to or following thermoresistance tests, namely the oxidative profile of semen alongside sperm capacitation patterns, and the levels of key proteins involved in capacitation signaling. Semen samples obtained from 30 stud bulls were frozen in the presence of 12.5, 25 or 50 μM KAE and compared to native ejaculates (negative control-CtrlN) as well as semen samples cryopreserved in the absence of KAE (positive control-CtrlC). A significant post-thermoresistance test maintenance of the sperm motility (p < 0.001), membrane (p < 0.001) and acrosome integrity (p < 0.001), mitochondrial activity (p < 0.001) and DNA integrity (p < 0.001) was observed following supplementation with all KAE doses in comparison to CtrlC. Experimental groups supplemented with all KAE doses presented a significantly lower proportion of prematurely capacitated spermatozoa (p < 0.001) when compared with CtrlC. A significant decrease in the levels of the superoxide radical was recorded following administration of 12.5 (p < 0.05) and 25 μM KAE (p < 0.01). At the same time, supplementation with 25 μM KAE in the cryopreservation medium led to a significant stabilization of the activity of Mg2+-ATPase (p < 0.05) and Na+/K+-ATPase (p < 0.0001) in comparison to CtrlC. Western blot analysis revealed that supplementation with 25 μM KAE in the cryopreservation medium prevented the loss of the protein kinase A (PKA) and protein kinase C (PKC), which are intricately involved in the process of sperm activation. In conclusion, we may speculate that KAE is particularly efficient in the protection of sperm metabolism during the cryopreservation process through its ability to promote energy synthesis while quenching excessive ROS and to protect enzymes involved in the process of sperm capacitation and hyperactivation. These properties may provide supplementary protection to spermatozoa undergoing the freeze-thaw process.

Epigallocatechin-3-gallate derived polymer coated Prussian blue for synergistic ROS elimination and antibacterial therapy

Reactive oxygen species (ROS) play a vital role in wound healing process by fighting against invaded bacteria. However, excess ROS at the wound sites lead to oxidative stress that can trigger deleterious effects, causing cell death, tissue damage and chronic inflammation. Therefore, we fabricated a core–shell structured nanomedicine with antibacterial and antioxidant properties via a facile and green strategy. Specifically, Prussian blue (PB) nanozyme was fabricated and followed by coating a layer of epigallocatechin-3-gallate (EGCG)-derived polymer via polyphenolic condensation reaction and self-assembly process, resulting in PB@EGCG. The introduction of PB core endowed EGCG-based polyphenol nanoparticles with excellent NIR-triggered photothermal properties. Besides, owing to multiple enzyme-mimic activity of PB and potent antioxidant capacity of EGCG-derived polymer, PB@EGCG exhibited a remarkable ROS-scavenging ability, mitigated intracellular ROS level and protected cells from oxidative damage. Under NIR irradiation (808 nm, 1.5 W/cm2), PB@EGCG (50 µg/mL) exerted synergistic EGCG-derived polymer-photothermal antibacterial activity against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus).In vivo therapeutic effect was evaluated using a S. aureus-infected rat model indicated PB@EGCG with a prominent bactericidal ability could modulate the inflammatory microenvironment and accelerate wound healing. Overall, this dual-functional nanomedicine provides a promising strategy for efficient antibacterial therapy.

Selenium-mercury interactions and relationship to aquatic toxicity: A review.

A review of the literature pertaining to selenium-mercury (Se/Hg) interactions in aquatic species was performed to provide insight into the mechanisms allowing for the reported changes in bioaccumulation and toxicity that have been observed when the two elements occur at elevated concentrations. Selenium (Se) has been shown to protect against mercury (Hg) toxicity in all animal models evaluated (fish, birds, mammals, and plants). To explore the interaction between the two elements, data are presented on concentrations of both elements in wild-caught fish at numerous locations. The data show that most fish have Se/Hg ratios >1.0. The importance of this ratio has been reported, with suggestions that the protective interaction is due in large part to the formation of HgSe. Data show that when the Se/Hg molar ratio is <1.0 in the diet of fish and animals, Hg toxicity will be expressed, provided that the Hg concentration is sufficiently high. This toxicity is likely the result of Se deficiency leading to an excess of reactive oxygen species. Laboratory fish toxicity studies reviewed show that Se toxicity can be reduced or eliminated when Hg is added to the diet in moderate amounts. Field studies have shown reduced accumulation of Hg when Se concentrations are increased. When Hg in the diet is significantly elevated (usually >10 µg/g), toxicity is expressed regardless of the Se present. Likewise, amelioration of Se toxicity by Hg occurs over a limited range. Tissue thresholds for Se toxicity have been derived primarily from studies where fish eggs were extracted from wild fish and embryo deformities were observed; however, the amount of Hg in the fish or ovaries was not considered, which could lead to uncertainty in the toxicity threshold. It is recommended that both elements be measured and evaluated when performing risk assessments and setting water quality criteria. Integr Environ Assess Manag 2024;00:1-11. © 2024 SETAC.

Development of Cu(II) 4-hydroxybenzoylhydrazone complexes that induce mitochondrial DNA damage and mitochondria-mediated apoptosis in liver cancer

Cisplatin remains the most widely used chemotherapeutic agent in cancer treatment; however, its inherent drawbacks have fueled the development of novel metalloanticancer drugs. In this study, two novel Cu(II) complexes (Cu1 and Cu2) were designed and synthesized. Notably, these Cu(II) complexes showed higher cytotoxicity against HL-7402 cells than cisplatin. Moreover, Cu(II) complexes significantly inhibited liver cancer growth in a xenograft model. A mechanism study revealed that the Cu(II) complexes reduced the mitochondrial membrane potential of cancer cells, produced excessive reactive oxygen species (ROS), induced mitochondrial DNA (mtDNA) damage, and ultimately facilitated cancer cell apoptosis.

Exogenous ascorbic acid as a potent regulator of antioxidants, osmo-protectants, and lipid peroxidation in pea under salt stress

Pea (Pisum sativum L.), a globally cultivated leguminous crop valued for its nutritional and economic significance, faces a critical challenge of soil salinity, which significantly hampers crop growth and production worldwide. A pot experiment was carried out in the Botanical Garden, The Islamia University of Bahawalpur to alleviate the negative impacts of sodium chloride (NaCl) on pea through foliar application of ascorbic acid (AsA). Two pea varieties Meteor (V1) and Sarsabz (V2) were tested against salinity, i.e. 0 mM NaCl (Control) and 100 mM NaCl. Three levels of ascorbic acid 0 (Control), 5 and 10 mM were applied through foliar spray. The experimental design was completely randomized (CRD) with three replicates. Salt stress resulted in the suppression of growth, photosynthetic activity, and yield attributes in pea plants. However, the application of AsA treatments effectively alleviated these inhibitory effects. Under stress conditions, the application of AsA treatment led to a substantial increase in chlorophyll a (41.1%), chl. b (56.1%), total chl. contents (44.6%) and carotenoids (58.4%). Under salt stress, there was an increase in Na+ accumulation, lipid peroxidation, and the generation of reactive oxygen species (ROS). However, the application of AsA increased the contents of proline (26.9%), endogenous AsA (23.1%), total soluble sugars (17.1%), total phenolics (29.7%), and enzymatic antioxidants i.e. SOD (22.3%), POD (34.1%) and CAT (39%) in both varieties under stress. Salinity reduced the yield attributes while foliarly applied AsA increased the pod length (38.7%), number of pods per plant (40%) and 100 seed weight (45.2%). To sum up, the application of AsA alleviated salt-induced damage in pea plants by enhancing photosynthetic pigments, both enzymatic and non-enzymatic activities, maintaining ion homeostasis, and reducing excessive ROS accumulation through the limitation of lipid peroxidation. Overall, V2 (Sarsabz) performed better as compared to the V1 (Meteor).

Enhancing 7-dehydrocholesterol suppresses brain ferroptosis and tissue injury after neonatal hypoxia–ischemia

Neonatal hypoxic-ischemic brain injury (HIBI) results in part from excess reactive oxygen species and iron-dependent lipid peroxidation (i.e. ferroptosis). The vitamin D precursor 7-dehydrocholesterol (7-DHC) may inhibit iron-dependent lipid peroxidation. Primary neurons underwent oxygen and glucose deprivation (OGD) injury and treatment with 7-DHC-elevating medications such as cariprazine (CAR) or vehicle. Postnatal day 9 mice underwent sham surgery or carotid artery ligation and hypoxia and received intraperitoneal CAR. In neurons, CAR administration resulted in significantly increased cell survival compared to vehicle controls, whether administered 48 h prior to or 30 min after OGD, and was associated with increased 7-DHC. In the mouse model, malondialdehyde and infarct area significantly increased after HIBI in the vehicle group, which were attenuated by post-treatment with CAR and were negatively correlated with tissue 7-DHC concentrations. Elevating 7-DHC concentrations with CAR was associated with improved cellular and tissue viability after hypoxic-ischemic injury, suggesting a novel therapeutic avenue.

A Self-Amplifying ROS-Responsive Nanoplatform for Simultaneous Cuproptosis and Cancer Immunotherapy.

Cuproptosis is an emerging cell death pathway that depends on the intracellular Cu ions. Elesclomol (ES) as an efficient Cu ionophore can specifically transport Cu into mitochondria and trigger cuproptosis. However, ES can be rapidly removed and metabolized during intravenous administration, leading to a short half-life and limited tumor accumulation, which hampers its clinical application. Here, the study develops a reactive oxygen species (ROS)-responsive polymer (PCP) based on cinnamaldehyde (CA) and polyethylene glycol (PEG) to encapsulate ES-Cu compound (EC), forming ECPCP. ECPCP significantly prolongs the systemic circulation of EC and enhances its tumor accumulation. After cellular internalization, the PCP coating stimulatingly dissociates exposing to the high-level ROS, and releases ES and Cu, thereby triggering cell death via cuproptosis. Meanwhile, Cu2+-stimulated Fenton-like reaction together with CA-stimulated ROS production simultaneously breaks the redox homeostasis, which compensates for the insufficient oxidative stress treated with ES alone, in turn inducing immunogenic cell death of tumor cells, achieving simultaneous cuproptosis and immunotherapy. Furthermore, the excessive ROS accelerates the stimuli-dissociation of ECPCP, forming a positive feedback therapy loop against tumor self-alleviation. Therefore, ECPCP as a nanoplatform for cuproptosis and immunotherapy improves the dual antitumor mechanism of ES and provides a potential optimization for ES clinical application.

Bioactive Nanofiber-Hydrogel Composite Regulates Regenerative Microenvironment for Skeletal Muscle Regeneration after Volumetric Muscle Loss.

Volumetric muscle loss (VML) is a severe form of muscle trauma that exceeds the regenerative capacity of skeletal muscle tissue, leading to substantial functional impairment. The abnormal immune response and excessive reactive oxygen species (ROS) accumulation hinder muscle regeneration following VML. Here, an interfacial cross-linked hydrogel-poly(ε-caprolactone) nanofiber composite, that incorporates both biophysical and biochemical cues to modulate the immune and ROS microenvironment for enhanced VML repair, is engineered. The interfacial cross-linking is achieved through a Michael addition between catechol and thiol groups. The resultant composite exhibits enhanced mechanical strength without sacrificing porosity. Moreover, it mitigates oxidative stress and promotes macrophage polarization toward a pro-regenerative phenotype, both in vitro and in a mouse VML model. 4 weeks post-implantation, mice implanted with the composite show improved grip strength and walking performance, along with increased muscle fiber diameter, enhanced angiogenesis, and more nerve innervation compared to control mice. Collectively, these results suggest that the interfacial cross-linked nanofiber-hydrogel composite could serve as a cell-free and drug-free strategy for augmenting muscle regeneration by modulating the oxidative stress and immune microenvironment at the VML site.

Assessment of the changes in growth, photosynthetic traits and gene expression in Cynodon dactylon against drought stress

Drought stress considered a key restrictive factor for a warm-season bermudagrass growth during summers in China. Genotypic variation against drought stress exists among bermudagrass (Cynodon sp.), but the selection of highly drought-tolerant germplasm is important for its growth in limited water regions and for future breeding. Our study aimed to investigate the most tolerant bermudagrass germplasm among thirteen, along latitude and longitudinal gradient under a well-watered and drought stress condition. Current study included high drought-resistant germplasm, “Tianshui” and “Linxiang”, and drought-sensitive cultivars; “Zhengzhou” and “Cixian” under drought treatments along longitude and latitudinal gradients, respectively. Under water deficit conditions, the tolerant genotypes showed over-expression of a dehydrin gene cdDHN4, antioxidant genes Cu/ZnSOD and APX which leads to higher antioxidant activities to scavenge the excessive reactive oxygen species and minimizing the membrane damage. It helps in maintenance of cell membrane permeability and osmotic adjustment by producing organic osmolytes. Proline an osmolyte has the ability to keep osmotic water potential and water use efficiency high via stomatal conductance and maintain transpiration rate. It leads to optimum CO2 assimilation rate, high chlorophyll contents for photosynthesis and elongation of leaf mesophyll, palisade and thick spongy cells. Consequently, it results in elongation of leaf length, stolon and internode length; plant height and deep rooting system. The CdDHN4 gene highly expressed in “Tianshui” and “Youxian”, Cu/ZnSOD gene in “Tianshui” and “Linxiang” and APX gene in “Shanxian” and “Linxiang”. The genotypes “Zhongshan” and “Xiaochang” showed no gene expression under water deficit conditions. Our results indicate that turfgrass show morphological modifications firstly when subjected to drought stress; however the gene expression is directly associated and crucial for drought tolerance in bermudagrass. Hence, current research has provided excellent germplasm of drought tolerant bermudagrass for physiological and molecular study and future breeding.

Calcium channel inhibitor and extracellular calcium improve aminoglycoside-induced hair cell loss in zebrafish.

Aminoglycosides are commonly used antibiotics for treatment of gram-negative bacterial infections, however, they might act on inner ear, leading to hair-cell death and hearing loss. Currently, there is no targeted therapy for aminoglycoside ototoxicity, since the underlying mechanisms of aminoglycoside-induced hearing impairments are not fully defined. This study aimed to investigate whether the calcium channel blocker verapamil and changes in intracellular & extracellular calcium could ameliorateaminoglycoside-induced ototoxicity in zebrafish. The present findings showed that a significant decreased number of neuromasts in the lateral lines of zebrafish larvae at 5days' post fertilization after neomycin (20μM) and gentamicin (20mg/mL) exposure, which was prevented by verapamil. Moreover, verapamil (10-100μM) attenuated aminoglycoside-induced toxic response in different external calcium concentrations (33-3300μM). The increasing extracellular calcium reduced hair cell loss from aminoglycoside exposure, while lower calcium facilitated hair cell death. In contrast, calcium channel activator Bay K8644 (20μM) enhanced aminoglycoside-induced ototoxicity and reversed the protective action of higher external calcium on hair cell loss. However, neomycin-elicited hair cell death was not altered by caffeine, ryanodine receptor (RyR) agonist, and RyR antagonists, including thapsigargin, ryanodine, and ruthenium red. The uptake ofneomycininto hair cells was attenuated by verapamil and under high external calcium concentration. Consistently, the production of reactive oxygen species (ROS) in neuromasts exposed to neomycin was also reduced by verapamil and high external calcium. Significantly, zebrafish larvae when exposed to neomycin exhibited decreased swimming distances in reaction to droplet stimulus when compared to the control group. Verapamil and elevated external calcium effectively protected the impaired swimming ability of zebrafish larvae induced by neomycin. These data imply that prevention of hair cell damage correlated with swimming behavior against aminoglycoside ototoxicity by verapamil and higher external calcium might be associated with inhibition of excessive ROS production andaminoglycoside uptake through cation channels. These findings indicate that calcium channel blocker and higher external calcium could be applied to protect aminoglycoside-induced listening impairments.

DNA methylation-mediated ROS production contributes to seed abortion in litchi

Although there is increasing evidence suggesting that DNA methylation regulates seed development, the underlying mechanisms remain poorly understood. Therefore, we aimed to shed light on this by conducting whole-genome bisulfite sequencing using seeds from the large-seeded cultivar 'HZ' and the abortive-seeded cultivar 'NMC'. Our analysis revealed that the 'HZ' seeds exhibited a hypermethylation level compared to the 'NMC' seeds. Furthermore, we found that the genes associated with differentially methylated regions (DMRs) and differentially expressed genes (DEGs) were mainly enriched in the reactive oxygen species (ROS) metabolic pathway. To investigate this further, we conducted nitroblue tetrazolium (NBT) and 2,7-Dichlorodihydrofluorescein (DCF) staining, which demonstrated a significantly higher amount of ROS in the 'NMC' seeds compared to the 'HZ' seeds. Moreover, we identified that the gene LcGPX6, involved in ROS scavenging, exhibited hypermethylation levels and parallelly lower expression levels in 'NMC' seeds compared to 'HZ' seeds. Interestingly, the ectopic expression of LcGPX6 in Arabidopsis enhanced ROS scavenging and resulted in lower seed production. Together, we suggest that DNA methylation-mediated ROS production plays a significant role in seed development in litchi, during which hypermethylation levels of LcGPX6 might repress its expression, resulting in the accumulation of excessive ROS and ultimately leading to seed abortion.

Reactive Oxygen Species Induced Upregulation of TRPV1 in Dorsal Root Ganglia Results in Low Back Pain in Rats.

Dorsal root ganglia (DRGs) contain sensory neurons that innervate intervertebral discs (IVDs) and may play a critical role in mediating low-back pain (LBP), but the potential pathophysiological mechanism needs to be clarified. A discogenic LBP model in rats was established by penetration of a lumbar IVD. The severity of LBP was evaluated through behavioral analysis, and the gene and protein expression levels of pro-algesic peptide substance P (SP) and calcitonin gene-related peptide (CGRP) in DRGs were quantified. The level of reactive oxygen species (ROS) in bilateral lumbar DRGs was also quantified using dihydroethidium staining. Subsequently, hydrogen peroxide solution or N-acetyl-L-cysteine was injected into DRGs to evaluate the change in LBP, and gene and protein expression levels of transient receptor potential vanilloid-1 (TRPV1) in DRGs were analyzed. Finally, an inhibitor or activator of TRPV1 was injected into DRGs to observe the change in LBP. The rats had remarkable LBP after disc puncture, manifesting as mechanical and cold allodynia and increased expression of the pro-algesic peptides SP and CGRP in DRGs. Furthermore, there was significant overexpression of ROS in bilateral lumbar DRGs, while manipulation of the level of ROS in DRGs attenuated or aggravated LBP in rats. In addition, excessive ROS in DRGs stimulated upregulation of TRPV1 in DRGs. Finally, activation or inhibition of TRPV1 in DRGs resulted in a significant increase or decrease of discogenic LBP, respectively, suggesting that ROS-induced TRPV1 has a strong correlation with discogenic LBP. Increased ROS in DRGs play a primary pathological role in puncture-induced discogenic LBP, and excessive ROS-induced upregulation of TRPV1 in DRGs may be the underlying pathophysiological mechanism to cause nerve sensitization and discogenic LBP. Therapeutic targeting of ROS or TRPV1 in DRGs may provide a promising method for the treatment of discogenic LBP.

ER stress promotes mitochondrial calcium overload and activates the ROS/NLRP3 axis to mediate fatty liver ischemic injury.

Fatty livers are widely accepted as marginal donors for liver transplantation but are more susceptible to liver ischemia and reperfusion (IR) injury. Increased macrophage-related inflammation plays an important role in the aggravation of fatty liver IR injury. Here, we investigate the precise mechanism by which endoplasmic reticulum (ER) stress activates macrophage NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) signaling by regulating mitochondrial calcium overload in fatty liver IR. Control- and high-fat diet-fed mice were subjected to a partial liver IR model. The ER stress, mitochondrial calcium levels, and NLRP3 signaling pathway in macrophages were analyzed. Liver steatosis exacerbated liver inflammation and IR injury and enhanced NLRP3 activation in macrophages. Myeloid NLRP3 deficiency attenuated intrahepatic inflammation and fatty liver injury following IR. Mechanistically, increased ER stress and mitochondrial calcium overload were observed in macrophages obtained from mouse fatty livers after IR. Suppression of ER stress by tauroursodeoxycholic acid effectively downregulated mitochondrial calcium accumulation and suppressed NLRP3 activation in macrophages, leading to decreased inflammatory IR injury in fatty livers. Moreover, Xestospongin-C-mediated inhibition of mitochondrial calcium influx decreased reactive oxygen species (ROS) expression in macrophages after IR. Scavenging of mitochondrial ROS by mito-TEMPO suppressed macrophage NLRP3 activation and IR injury in fatty livers, indicating that excessive mitochondrial ROS production was responsible for macrophage NLRP3 activation induced by mitochondrial calcium overload. Patients with fatty liver also exhibited upregulated activation of NLRP3 and the ER stress signaling pathway after IR. Our findings suggest that ER stress promotes mitochondrial calcium overload to activate ROS/NLRP3 signaling pathways within macrophages during IR-stimulated inflammatory responses associated with fatty livers.

Nicotinamide mononucleotide maintains cytoskeletal stability and fortifies mitochondrial function to mitigate oocyte damage induced by Triocresyl phosphate

Triocresyl phosphate (TOCP) was commonly used as flame retardant, plasticizer, lubricant, and jet fuel additive. Studies have shown adverse effects of TOCP on the reproductive system. However, the potential harm brought by TOCP, especially to mammalian female reproductive cells, remains a mystery. In this study, we employed an in vitro model for the first time to investigate the effects of TOCP on the maturation process of mouse oocytes. TOCP exposure hampered the meiotic division process, as evidenced by a reduction in the extrusion of the first polar body from oocytes. Subsequent research revealed the disruption of the oocyte cell cytoskeleton induced by TOCP, resulting in abnormalities in spindle organization, chromosome alignment, and actin filament distribution. This disturbance further extended to the rearrangement of organelles within oocytes, particularly affecting the mitochondria. Importantly, after TOCP treatment, mitochondrial function in oocytes was impaired, leading to oxidative stress, DNA damage, cell apoptosis, and subsequent changes of epigenetic modifications. Supplementation with nicotinamide mononucleotide (NMN) alleviated the harmful effects of TOCP. NMN exerted its mitigating effects through two fundamental mechanisms. On one hand, NMN conferred stability to the cell cytoskeleton, thereby supporting nuclear maturation. On the other hand, NMN enhanced mitochondrial function within oocytes, reducing the excess reactive oxygen species (ROS), restoring meiotic division abnormalities caused by TOCP, preventing oocyte DNA damage, and suppressing epigenetic changes. These findings not only enhance our understanding of the molecular basis of TOCP induced oocyte damage but also offer a promising avenue for the potential application of NMN in optimizing reproductive treatment strategies.