Decreased Reactive Oxygen Species Generation Research Articles

Mitigating phthalate toxicity: The protective role of humic acid and clay in zebrafish larvae

This research study aimed to explore the mitigating effects of humic acid and clay on the toxicity induced by three different phthalates (DBP, DEP, DEHP) on zebrafish larvae growth. Prolonged exposure to DBP resulted in a concerning 87.33% mortality rate, significantly reduced to 7.3% when co-administered with humic acid. A similar reduction in mortality was observed for the other two phthalates (DEP and DEHP). Additionally, the introduction of phthalates with humic acid, clay, or their combination led to a significant decrease in the malformation rate in larvae.High-Performance Liquid Chromatography (HPLC) analysis of phthalates in treatments revealed a noteworthy decline in their concentration when combined with humic acid and clay. This suggests a reduced bioavailability of phthalates to larvae, aligning with diminished toxicity, lower mortality, fewer malformations, and improved organ development, as well as less oxidative stress. Furthermore, measurements of larval length and morphological scoring affirmed the protective role of humic acid and clay in promoting the normal growth of zebrafish. This study underscores the potential of environment modulators, such as humic acid and clay, as effective bioremediation agents against phthalate toxicity. The generation of reactive oxygen species (ROS), indicative of oxidative stress, was markedly higher in larvae treated solely with phthalates compared to the control. Conversely, larvae treated with a combination of phthalates and humic acid or clay exhibited a significant decrease in ROS generation, signaling a decline in oxidative stress. Histopathological analysis of adult fish subjected to various treatments revealed significant damage to vital organs like the liver and intestine when treated with phthalates alone. However, when phthalates were introduced with humic acid, clay, or both, the morphology closely resembled that of the control, reinforcing the protective role of humic acid and clay in zebrafish development against administered phthalates.

High-throughput synchronous erythrocyte cellular antioxidant activity and protection screening of phenolic-rich extracts: Protocol validation and applications

Oxidative/nitrosative damage takes part in chronic disease development, which generates an urgent need for intervention and better therapies to manage them. The scientific community has demanded easy-to-run, cheap, and reliable methods for cellular antioxidant activity assays. This work standardised and validated an erythrocyte cellular antioxidant activity and membrane protection/injury (HERYCA-P) protocol to study food-derive extracts. The method measures intracellular reactive oxygen species (ROS) generation, lipoperoxidation, and haemolysis induced by 2,2′-azobis(2-amidinopropane) dihydrochloride. Quercetin decreased ROS generation by 50.4% and haemolysis by 2.2%, while ascorbic acid inhibited lipid peroxidation by 40.1%. Total phenolic contents of teas were correlated with decreased ROS generation (r = −0.924), lipoperoxidation (r = −0.951), and haemolysis (r = −0.869). The erythrocyte ROS generation and lipoperoxidation were also associated with CUPRAC (r = −0.925; r = −0.951) and hydroxyl radical scavenging activity (r = −0.936; r = −0.949). The precision rates of antioxidant standards and tea samples were below 15%. HERYCA-P is feasible as a complementary antioxidant assay for food matrices.

Ammidin ameliorates myocardial hypoxia/reoxygenation injury by inhibiting the ACSL4/AMPK/mTOR-mediated ferroptosis pathway

ObjectiveThe aim of the present study was to investigate the therapeutic effect of ammidin on hypoxia/reoxygenation (H/R) injury in primary neonatal rat cardiomyocytes by observing the role of ferroptosis in the process of H/R injury, and to verify its target and regulatory signaling pathways.MethodsThe network pharmacology analysis was used to predict the biological processes, core targets and related signaling pathways of Angelica dahurica in the treatment of ferroptosis. Cell viability was assessed using live cell imaging and cell counting kit-8. Lactate dehydrogenase (LDH), reactive oxygen species (ROS) production, and malondialdehyde (MDA), superoxide dismutase (SOD) and mitochondrial membrane potential (MMP) content were determined to assess the level of ferroptosis. Western blotting was performed to measure protein expression.ResultsNetwork pharmacology predicted that Acyl-CoA synthetase long chain family member 4 (ACSL4) was highly associated with myocardial H/R injury in the intersection of Angelica dahurica and ferroptosis. The top three active components of Angelica dahurica were found to be mandenol, alloisoimperatorin and ammidin, among which ammidin was found to have the strongest binding to the target proteins of the ACSL4/AMPK/mTOR pathway. H/R reduced the viability of cardiomyocytes, while the inhibition of ferroptosis by ferrostatin-1 alleviated the H/R-induced inhibition of cardiomyocyte viability. This was evidenced by the increased cell viability, SOD release, MMP level and glutathione peroxidase 4 (GPX4) protein expression, as well as the decreased LDH and MDA release and ROS production and ACSL4 protein expression (P < 0.05). To verify the existence of ferroptosis in myocardial hypoxia/reoxygenation injury. In addition, ammidin increased cell viability and GPX4 protein expression (P < 0.05), decreased ROS generation, and MDA and MTT expression (P < 0.05), then inhibited ferroptosis, and finally alleviated myocardial H/R injury by regulating the ACSL4/AMPK signaling pathway.ConclusionsNetwork pharmacology was used to predict the correlation between ammidin and ferroptosis following myocardial H/R injury. It was demonstrated that ammidin may regulate ferroptosis by inhibiting the ACSL4/AMPK/mTOR signaling pathway and reduce H/R injury in cardiomyocytes.

A mitochondrial pentatricopeptide repeat protein enhances cold tolerance by modulating mitochondrial superoxide in rice

Cold stress affects rice growth and productivity. Defects in the plastid-localized pseudouridine synthase OsPUS1 affect chloroplast ribosome biogenesis, leading to low-temperature albino seedlings and accumulation of reactive oxygen species (ROS). Here, we report an ospus1-1 suppressor, sop10. SOP10 encodes a mitochondria-localized pentatricopeptide repeat protein. Mutations in SOP10 impair intron splicing of the nad4 and nad5 transcripts and decrease RNA editing efficiency of the nad2, nad6, and rps4 transcripts, resulting in deficiencies in mitochondrial complex I, thus decrease ROS generation and rescuing the albino phenotype. Overexpression of different compartment-localized superoxide dismutases (SOD) genes in ospus1-1 reverses the ROS over-accumulation and albino phenotypes to various degrees, with Mn-SOD reversing the best. Mutation of SOP10 in indica rice varieties enhances cold tolerance with lower ROS levels. We find that the mitochondrial superoxide plays a key role in rice cold responses, and identify a mitochondrial superoxide modulating factor, informing efforts to improve rice cold tolerance.

Thioredoxin-1 promotes the restoration of alveolar bone in periodontitis with diabetes

Treatment of periodontitis in people with diabetes remains challenging. The present study aimed to investigate the therapeutic potential of thioredoxin-1 (TRX1) in periodontitis with diabetes, as well as its role in modulating osteogenic differentiation. Our findings indicated that the production of reactive oxygen species (ROS) was elevated, while the expression of TRX1 was significantly reduced in the periodontal tissues of periodontitis mice with diabetes. Furthermore, knockdown of TRX1 in periodontal ligament stem cells (PDLSCs) resulted in the inhibition of osteogenic differentiation through disrupting Wnt/β-catenin signaling. However, this inhibition was restored upon administration of recombinant human TRX1 (rhTRX1). Importantly, rhTRX1 treatment decreased ROS generation, activated Wnt/β-catenin signal pathway and considerably promoted the alveolar bone repair of periodontitis mice with diabetes. These findings highlighted the crucial protective role of TRX1 in periodontitis with diabetes and suggested that it may serve as a potential therapeutic target for refractory periodontitis associated with oxidative stress.

Multiple ingredients of a Chinese medicine formula Sheng-Mai-San coordinately attenuate doxorubicin-induced cardiotoxicity

BackgroundDoxorubicin (DOX) is one of the most widely used antitumor drugs. However, continuous DOX treatment would cause crucial cardiotoxicity side effect, accompanied with the accumulation of reactive oxygen species (ROS), impaired mitochondrial functions and increased cardiomyocyte death. Sheng-Mai-San (SMS), a traditional Chinese medicine widely used for cardiovascular diseases, has been clinically used to counteract cardiotoxicity of DOX, yet the underlying mechanism is largely unknown. MethodsWe utilized JC-1 assay to examine the effects of SMS and its components under DOX treatment in rat cardiomyocytes (H9c2 cells), and further investigated the functional mechanisms of active components in SMS formula via transcriptome sequencing, bioinformatics analysis and molecular experiments. ResultsWe identified three functional components of SMS in protecting cardiomyocytes from DOX-induced damages and revealed the coordinated regulatory mechanisms of these components, namely ginsenoside Rh2 (Rh2), Ophiopogonin D (OpD) and Schisandrin B (SchB). We found that Rh2 mainly acts to restore mitochondrial functions and to decrease ROS generation by enhancing fatty acid metabolism and antioxidant activity, OpD has assistive roles in mitochondrial function repair, and SchB mainly functions by inhibiting cell death, as well as activating cytoskeleton and ECM organization. ConclusionThis study provides supporting evidence for the clinical application of SMS to reduce the cardiotoxicity effects of DOX treatment, and also sheds light for the mechanistic studies of traditional Chinese medicine.

Boosting Mitochondrial Potential: An Imperative Therapeutic Intervention in Amyotrophic Lateral Sclerosis.

Amyotrophic Lateral Sclerosis (ALS) is a progressive and terminal neurodegenerative disorder. Mitochondrial dysfunction, imbalance of cellular bioenergetics, electron chain transportation and calcium homeostasis are deeply associated with the progression of this disease. Impaired mitochondrial functions are crucial in rapid neurodegeneration. The mitochondria of ALS patients are associated with deregulated Ca2+ homeostasis and elevated levels of reactive oxygen species (ROS), leading to oxidative stress. Overload of mitochondrial calcium and ROS production leads to glutamatereceptor mediated neurotoxicity. This implies mitochondria are an attractive therapeutic target. The aim of this review is to brief the latest developments in the understanding of mitochondrial pathogenesis in ALS and emphasize the restorative capacity of therapeutic candidates. In ALS, mitochondrial dysfunction is a well-known phenomenon. Various therapies targeted towards mitochondrial dysfunction aim at decreasing ROS generation, increasing mitochondrial biogenesis, and inhibiting apoptotic pathways. Some of the therapies briefed in this review may be categorized as synthetic, natural compounds, genetic materials, and cellular therapies. The overarching goals of mitochondrial therapies in ALS are to benefit ALS patients by slowing down the disease progression and prolonging overall survival. Despite various therapeutic approaches, there are many hurdles in the development of a successful therapy due to the multifaceted nature of mitochondrial dysfunction and ALS progression. Intensive research is required to precisely elucidate the molecular pathways involved in the progression of mitochondrial dysfunctions that ultimately lead to ALS. Because of the multifactorial nature of ALS, a combination therapy approach may hold the key to cure and treat ALS in the future.

H2O2 transit through the mitochondrial intermembrane space promotes tumor cell growth in vitro and in vivo

Cancer cells experience increased levels of oxidant stress as a consequence of oncogene activation, nucleotide biosynthesis, and growth factor receptor signaling. Mitochondria contribute to this redox stress by generating reactive oxygen species (ROS) along the electron transport chain, which are released to the matrix and the intermembrane space (IMS). Assessing the contribution of mitochondrial ROS in cancer cells is technically difficult, as electron transport chain inhibitors can increase or decrease ROS generation, while they also block oxidative phosphorylation and ATP synthesis. Mitochondria-targeted antioxidant compounds can scavenge ROS in the matrix compartment but do not act on ROS released to the IMS. We assessed the importance of mitochondrial ROS for tumor cell proliferation, survival, and for tumor xenograft growth by stably expressing a hydrogen peroxide (H2O2) scavenger, peroxiredoxin-5, in the mitochondrial IMS (IMS-Prdx5) in 143B osteosarcoma and HCT116 colorectal cancer cell lines. IMS-Prdx5 attenuates hypoxia-induced ROS signaling as assessed independently in cytosol and IMS, HIF-1α stabilization and activity, and cellular proliferation under normoxic and hypoxic culture conditions. It also suppressed tumor growth invivo. Stable expression of nondegradable HIF-1α only partially rescued proliferation in IMS-Prdx5-expressing cells, indicating that mitochondrial H2O2 signaling contributes to tumor cell proliferation and survival through HIF-dependent and HIF-independent mechanisms.

In Vitro Anti-Inflammatory and Antioxidant Activities of pH-Responsive Resveratrol-Urocanic Acid Nano-Assemblies.

Inflammatory environments provide vital biochemical stimuli (i.e., oxidative stress, pH, and enzymes) for triggered drug delivery in a controlled manner. Inflammation alters the local pH within the affected tissues. As a result, pH-sensitive nanomaterials can be used to effectively target drugs to the site of inflammation. Herein, we designed pH-sensitive nanoparticles in which resveratrol (an anti-inflammatory and antioxidant compound (RES)) and urocanic acid (UA) were complexed with a pH-sensitive moiety using an emulsion method. These RES-UA NPs were characterized by transmission electron microscopy, dynamic light scattering, zeta potential, and FT-IR spectroscopy. The anti-inflammatory and antioxidant activities of the RES-UA NPs were assessed in RAW 264.7 macrophages. The NPs were circular in shape and ranged in size from 106 to 180 nm. The RES-UA NPs suppressed the mRNA expression of the pro-inflammatory molecules inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages in a concentration-dependent manner. Incubation of LPS-stimulated macrophages with RES-UA NPs reduced the generation of reactive oxygen species (ROS) in a concentration-dependent manner. These results suggest that pH-responsive RES-UA NPs can be used to decrease ROS generation and inflammation.

Metformin Acutely Mitigates Oxidative Stress in Human Atrial Tissue: A Pilot Study in Overweight Non-Diabetic Cardiac Patients.

Metformin, the first-line drug in type 2 diabetes mellitus, elicits cardiovascular protection also in obese patients via pleiotropic effects, among which the anti-oxidant is one of the most investigated. The aim of the present study was to assess whether metformin can acutely mitigate oxidative stress in atrial tissue harvested from overweight non-diabetic patients. Right atrial appendage samples were harvested during open-heart surgery and used for the evaluation of reactive oxygen species (ROS) production by means of confocal microscopy (superoxide anion) and spectrophotometry (hydrogen peroxide). Experiments were performed after acute incubation with metformin (10 µM) in the presence vs. absence of angiotensin II (AII, 100 nM), lipopolysaccharide (LPS, 1 μg/mL), and high glucose (Gluc, 400 mg/dL). Stimulation with AII, LPS, and high Gluc increased ROS production. The magnitude of oxidative stress correlated with several echocardiographic parameters. Metformin applied in the lowest therapeutic concentration (10 µM) was able to decrease ROS generation in stimulated but also non-stimulated atrial samples. In conclusion, in a pilot group of overweight non-diabetic cardiac patients, acute incubation with metformin at a clinically relevant dose alleviated oxidative stress both in basal conditions and conditions that mimicked the activation of the renin-angiotensin-aldosterone system, acute inflammation, and uncontrolled hyperglycemia.

Abstract 12689: Electron Transport Chain Inhibition to Decrease Reperfusion Injury in Transplanted Donation After Circulatory Death Rat Hearts

Introduction: Intrinsic to the donation after circulatory death (DCD) donation is ischemia and reperfusion injury, primarily mediated through release of reactive oxygen species (ROS) from the damaged mitochondria. Amobarbital (AMO) is a transient, reversible inhibitor of complex I known to decrease ROS generation. We studied whether AMO treatment during reperfusion can improve function in transplanted DCD hearts. Methods: Sprague Dawley rats, were assigned to four heart donor groups- DCD or DCD+AMO and control beating-heart donor (CBD) or CBD+AMO (n=6-8 each). Donor rats were anesthetized using ketamine/xylazine, intubated and connected to a ventilator. The carotid access was used to deliver heparin (1000 U/kg) and vecuronium bromide (4 mg/kg) to paralyze diaphragmatic muscles. The DCD process was initiated by disconnecting the ventilator. Donor hearts were procured following 25 minutes of in-vivo ischemia in the DCD groups, while CBD hearts were procured without terminating the ventilation. At procurement, after clamping the aortic arch, all donor hearts received 10 ml of University of Wisconsin cardioplegia solution delivered through the carotid cannula. The CBD+AMO and DCD+AMO groups received AMO (2 mM), dissolved in the cardioplegia. Heterotopic heart transplantation was performed in recipient rat’s abdomen. After 14 days the transplanted heart function was measured with a balloon tip catheter. Results: Compared to CBD hearts, DCD hearts had significantly lower developed pressure, the rate pressure product (developed pressure times heart rate), and negative dP/dt indicating decreased contractile and impaired diastolic function (Figure). AMO treatment of the DCD hearts resulted in significantly improved cardiac function compared to the untreated DCD hearts. Conclusions: A single treatment with AMO during the heart procurement improves the transplanted DCD heart function which was comparable to the control CBD hearts.

G6PD promotes cell proliferation and dexamethasone resistance in multiple myeloma via increasing anti-oxidant production and activating Wnt/β-catenin pathway

BackgroundGlucose-6-phosphate dehydrogenase (G6PD) as the rate-limiting enzyme in the pentose phosphate pathway (PPP) is well-established as an aberrantly expressed protein in numerous clinical diseases; however, its role in cancer, specifically in multiple myeloma (MM) remains elusive.MethodsIn this study, serum metabolites in 70 normal people and 70 newly diagnosed MM patients were analyzed using untargeted metabolomics and the results were verified using ELISA. The survival analysis of multiple clinical datasets was performed to identify a potential target gene in MM. The oncogenic role of G6PD was investigated using lentivirus-based overexpression or knockdown of G6PD using RNAi or an inhibitor in vitro, and in a xenograft mouse model in vivo. The mechanisms of induced Dexamethasone (Dexa)-resistance of G6PD were further explored using the above established MM cell lines in vitro.ResultsBased on the screening of potential genes, PPP was shown to be involved in the occurrence of MM, which was evidenced by the differential expression of serum metabolites of G6P and Dehydroepiandrosterone sulfate (DHEAS, the more stable sulfate ester form of an endogenously uncompetitive G6PD inhibitor known as DHEA). Elevated G6PD promoted MM cell proliferation. Mechanistically, high G6PD expression enhanced enzymatic generation of the antioxidant NADPH via the PPP and decreased the production of reactive oxygen species (ROS), thus inducing the proliferation and Dexa resistance in MM cells. Furthermore, canonical Wnt/β-catenin signaling also participated in regulating G6PD-induced drug resistance and cellular redox levels of ROS. Intriguingly, DHEA treatment could enhance the sensitivity of MM cells to Dexa primarily through augmenting cellular oxidative stress.ConclusionsOur data demonstrate that G6PD enhances the generation of the enzymatic anti-oxidant NADPH and decreases ROS generation, thereby promoting resistance to Dexa-induced apoptosis via the enzymatic PPP and non-enzymatic Wnt/β-catenin signaling pathway in MM. Targeting G6PD to harness cellular redox may serve as a promising novel strategy for the management of MM.

Arbuscular mycorrhizal fungi contribute to reactive oxygen species homeostasis of Bombax ceiba L. under drought stress.

Drought stress is one of the major abiotic factors limiting plant growth and causing ecological degradation. The regulation of reactive oxygen species (ROS) generation and ROS scavenging is essential to plant growth under drought stress. To investigate the role of arbuscular mycorrhizal fungi (AMF) on ROS generation and ROS scavenging ability under drought stress in Bombax ceiba, the ROS content, the expression levels of respiratory burst oxidase homologue (Rbohs), and the antioxidant response were evaluated in AMF and NMF (non-inoculated AMF) plants under drought stress. 14 BcRboh genes were identified in the B. ceiba genome and divided into five subgroups based on phylogenetic analysis. The effect of AMF on the expression profiles of BcRbohs were different under our conditions. AMF mainly downregulated the expression of Rbohs (BcRbohA, BcRbohD, BcRbohDX2, BcRbohE, BcRbohFX1, and BcRbohI) in drought-stressed seedlings. For well-water (WW) treatment, AMF slightly upregulated Rbohs in seedlings. AMF inoculation decreased the malondialdehyde (MDA) content by 19.11 and 20.85%, decreased the O2⋅– production rate by 39.69 and 65.20% and decreased H2O2 content by 20.06 and 43.21% compared with non-mycorrhizal (NMF) plants under drought stress in root and shoot, respectively. In addition, AMF inoculation increased the non-enzymatic antioxidants glutathione (GSH) and ascorbic acid (AsA) content in roots by 153.52 and 28.18% under drought stress, respectively. The activities of antioxidant enzymes (SOD, PX, CAT, APX, GPX, GR, MDAR, and DHAR) all increased ranging from 19.47 - 131.54% due to AMF inoculation under drought stress. In conclusion, these results reveal that AMF inoculation can maintain ROS homeostasis by mitigating drought-induced ROS burst, via decreasing ROS generation and enhancing ROS scavenging ability of B. ceiba seedlings.

PSMB5 Alleviates Ulcerative Colitis by Inhibiting ROS-Dependent NLRP3 Inflammasome-Mediated Pyroptosis.

Ulcerative colitis (UC) is a chronic inflammatory disease. Intestinal mucosal injury is a significant factor in UC. Pyroptosis is a kind of programmed cell death induced by inflammatory caspases. Proteasome 20S subunit beta 5 (PSMB5) promotes cell viability. The purpose of this study was to determine the impact of PSMB5 on intestinal mucosal injury and to elucidate the underlying processes in dextran sulfate sodium- (DSS-) induced UC mice. Kunming (KM) mice received 3% DSS for 5 days to induce UC. We collected clinical symptoms, body weight, colon length, and histological changes. MDA (malondialdehyde) and SOD (superoxide dismutase) levels were determined using an ELISA assay. RT-PCR was used to assess the expression of IL-1β and IL-18. PSMB5 demonstrated a significant effect against UC by increasing body weight and colon length and decreasing DAI (disease activity index), colon macroscopic damage index (CMDI), histological injury scores, and reactive oxygen species (ROS), MDA, and SOD levels, thereby alleviating histopathological changes and inhibiting oxidative stress. HIEC-6 cells were exposed to lipopolysaccharide (LPS) condition with or without PSMB5, along with caspase-1 inhibitor (Z-VAD-FMK), NLRP3 inhibitor (MCC950), and ROS scavenger N-acetylcysteine (NAC). The viability of the cells, the release of lactate dehydrogenase (LDH), and intracellular ROS generation were determined using assay kits. Western blot analysis was used to determine the levels of NLRP3, ASC, cleaved caspase-1 (p20), pro-IL-1β, IL-1β, pro-IL-18, and IL-18. PSMB5 overexpression enhanced the inflammatory damage in LPS-treated HIEC-6 cells by activating the NLRP3 inflammasome and mediating pyroptosis, as demonstrated by increased LDH release and lower cell viability, as well as increased expression of NLRP3, ASC, cleaved caspase-1 (p20), IL-1, and IL-18. Meanwhile, NAC protected HIEC-6 cells from LPS-induced damage by reversing the activation of the NLRP3 inflammasome-mediated pyroptosis. In conclusion, PSMB5 may lower HIEC-6 cell susceptibility to LPS and ameliorate UC-induced HIEC-6 cell damage by decreasing ROS generation and hence inhibiting NLRP3-mediated pyroptosis.

Protective and anti-oxidative effects of curcumin and resveratrol on Aβ-oligomer-induced damage in the SH-SY5Y cell line

Alzheimer's disease (AD) is a degenerative disorder characterized by the loss of synapses and neurons in the brain, and results in the accumulation of amyloid-based neurotic plaques. Amyloid-β oligomers (AβO) are widely accepted as the main neurotoxin that induces oxidative stress and neuronal loss in AD. In this study, an oxidative stress model of the neuroblastoma SH-SY5Y cell line exposed to AβO was established to simulate an AD cell model. Exposure to AβO significantly reduced the viability of cultured SH-SY5Y cells (p < 0.05) and significantly increased intracellular reactive oxygen species (ROS) (p < 0.01). AβO exposure also induced oxidative stress in SH-SY5Y cells. Furthermore, AβO significantly increased the level of hyperphosphorylation of tau at sites T181 and T205 in SH-SY5Y cells (p < 0.01). Using edaravone, a free radical scavenger with neuroprotective properties, as the control, the possible protective and anti-oxidative effects of curcumin (40 μM) and resveratrol (20 μM) were evaluated. The results suggest that curcumin and resveratrol decreased ROS generation, attenuated oxidative stress, inhibited tau hyperphosphorylation, and protected SH-SY5Y cells from AβO damage. Both curcumin and resveratrol are promising supplements or medicine as therapeutic agents for the treatment of AD.

Inhibition of Hypoxia-Inducible Factor Prolyl-Hydroxylase Modulates Platelet Function.

Hypoxia-inducible factor-1α (HIF-1α) involves in redox reactions. Considering the role of reactive oxygen species (ROS) in platelet function, whether it regulates platelet function remains unclear. Using an inhibitor of HIF prolyl-hydroxylase, IOX-2, we intend to investigate its effect on platelet function. Human platelets were treated with IOX-2 (0, 10, 25, and 50 μM) followed by analysis of platelet aggregation, granule secretion, receptor expression, platelet spreading, or clot retraction. Additionally, IOX-2 (10 mg/kg) was injected intraperitoneally into mice to measure tail bleeding time and arterial thrombosis. IOX-2 significantly inhibited collagen-related peptide (CRP; 0.25 μg/mL) or thrombin (0.03 U/mL)-induced platelet aggregation and ATP release dose dependently without affecting P-selectin expression and the surface levels of glycoprotein (GP)Ibα, GPVI, or αIIbβ3. In addition, IOX-2-treated platelets presented significantly decreased spreading on fibrinogen or collagen and clot retraction. Moreover, IOX-2 administration into mice significantly impaired the in vivo hemostatic function of platelets and arterial thrombus formation without affecting the number of circulating platelets and coagulation factors (FVIII and FIX). Further, IOX-2 significantly upregulated HIF-1α in platelets, decreased ROS generation, and downregulated NOX1 expression. Finally, IOX-2 increased the phosphorylation level of VASP (Ser157/239), and inhibited the phosphorylation of p38 (Thr180/Tyr182), ERK1/2 (Thr202/Tyr204), AKT (Thr308/Ser473), and PKCδ (Thr505) in CRP- or thrombin-stimulated platelets. In conclusion, inhibition of HIF prolyl-hydroxylase modulates platelet function and arterial thrombus formation, possibly through upregulation of HIF-1α expression and subsequent inhibition of ROS generation, indicating that HIF-1α might be a novel target for the treatment of thrombotic disorders.

The Combination of Salidroside and Hedysari Radix Polysaccharide Inhibits Mitochondrial Damage and Apoptosis via the PKC/ERK Pathway

Background Beta-amyloid (Aβ) peptide is a widely recognized pathological marker of Alzheimer's disease (AD). Salidroside and Hedysari Radix polysaccharide (HRP) were extracted from Chinese herb medicine Rhodiola rosea L and Hedysarum polybotrys Hand-Mazz, respectively. The neuroprotective effects and mechanisms of the combination of salidroside and Hedysari Radix polysaccharide (CSH) against Aβ25–35 induced neurotoxicity remain unclear. Objective This study aims to investigate the neuroprotective effects and pharmacological mechanisms of CSH on Aβ25–35-induced HT22 cells. Materials and Methods HT22 cells were pretreated with various concentrations of salidroside or HRP for 24 h, followed by exposed to 20 μm Aβ25–35 in the presence of salidroside or RHP for another 24 h. In a CSH protective assay, HT22 cells were pretreated with 40 μm salidroside and 20 μg/mL HRP for 24 h. The cell viability assay, cell morphology observation, determination of mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and cell apoptosis rate were performed. The mRNA expression of protein kinase C-beta (PKCβ), Bax, and Bcl-2 were measured by qRT-PCR. The protein expression levels of cleaved caspase-3, Cyt-C, PKCβ, phospho-ERK1/2, Bax, and Bcl-2 were measured by Western blot. Results CSH treatment increased cell viability, MMP, and decreased ROS generation in Aβ25–35-induced HT22 cells. PKCβ and Bcl-2 mRNA expression were elevated by CSH while Bax was decreased. CSH increased the protein expression levels of PKCβ, Bcl-2, and phospho-ERK1/2, and decreased those of Bax, Cyt-C, and cleaved caspase-3. Conclusions CSH treatment have protective effects against Aβ25–35-induced cytotoxicity through decreasing ROS levels, increasing MMP, inhibiting early apoptosis, and regulating PKC/ERK pathway in HT22 cells. CSH may be a potential therapeutic agent for treating or preventing neurodegenerative diseases.

TMEM189 promotes breast cancer through inhibition of autophagy-regulated ferroptosis

Breast cancer is a leading cause of tumor-related death among women around the world, but its pathogenesis is still unclear. Transmembrane protein 189 (TMEM189) is widely expressed in many types of tissues and plays a critical role in tumorigenesis partly through mediating cell death. However, its regulatory function on breast cancer progression and particularly the underlying mechanisms have not been fully understood. In the present study, we found that TMEM189 knockdown significantly reduced the proliferation of breast cancer cells, while its over-expression facilitated the proliferative capacity of tumor cells. The effects of TMEM189 to promote breast cancer were validated in the constructed xenograft mouse models. RNA-sequencing studies subsequently showed that TMEM189 deletion was closely associated with ferroptosis signaling pathway, accompanied with elevated lipid reactive oxygen species (ROS) accumulation, cellular ROS production, malondialdehyde (MDA) and the intracellular iron releases. However, GSH levels in breast cancer cells were highly impeded upon TMEM189 inhibition. Intriguingly, we found that TMEM189 knockdown-induced ferroptotic cell death was considerably abolished after autophagy inhibitor 3-MA co-treatment, as evidenced by the markedly decreased ROS generation and intracellular iron accumulation. Moreover, TMEM189 ablation strongly up-regulated LC3BII and transferrin receptor 1 (TfR1) expression levels in breast cancer cells, whereas down-regulated p62 and GPX4. Importantly, the expression changes of these molecules related to autophagy and ferroptosis were almost diminished in response to 3-MA exposure, along with restored cell proliferation. These findings suggested that TMEM189 could inhibit autophagy to mediate ferroptosis in breast cancer cells. Collectively, all our findings revealed the therapeutic potential of TMEM189 in the treatment of breast cancer.

Role of Mitochondrial Dysfunction in the Pathogenesis of Cisplatin-Induced Myotube Atrophy.

Muscle atrophy is commonly observed during cisplatin chemotherapy, leading to a reduced QOL in cancer patients. Reduced skeletal muscle mass caused by cisplatin treatment results from the activation of ubiquitin ligases-Atrogin-1 and MuRF1, but the precise mechanisms are poorly understood. In this study, we investigated the possible involvement of mitochondrial dysfunction, including reactive oxygen species (ROS) generation and ATP production, in cisplatin-induced muscle atrophy. Skeletal C2C12 myotubes were treated with cisplatin, and gene and protein expression were evaluated. Mitochondrial mass, membrane potential, and ROS levels were measured using fluorescent dyes. Mitochondrial respiratory function, ATP production rates, and glycolytic capacity were also analyzed using an extracellular flux analyzer. Metabolomic analyses were performed using gas chromatography-tandem mass spectrometry. Cisplatin treatment reduced myosin heavy chain expression by activating the ubiquitin-proteasome system. Increased ROS production was observed after cisplatin treatment, followed by significant changes in apoptosis-related gene expression and decrease in mitochondrial mass, membrane potential, respiration, and ATP production. Glycolytic capacity and tricarboxylic acid (TCA) cycle metabolite levels were reduced with cisplatin treatment. Mitochondria-targeted antioxidant mitoquinone mesylate prevented up-regulation of Atrogin-1 gene expression and restored myosin heavy chain levels, accompanied by a decrease in ROS generation, but not mitochondrial ATP production. We concluded that cisplatin-induced myotube atrophy was associated with mitochondrial dysfunction. Reducing ROS generation, rather than promoting ATP production, could be a useful therapeutic strategy for preventing cisplatin-induced muscle atrophy.

Effects of Sodium Pyruvate on Vanadyl Sulphate-Induced Reactive Species Generation and Mitochondrial Destabilisation in CHO-K1 Cells.

Vanadium is ranked as one of the world’s critical metals considered important for economic growth with wide use in the steel industry. However, its production, applications, and emissions related to the combustion of vanadium-containing fuels are known to cause harm to the environment and human health. Pyruvate, i.e., a glucose metabolite, has been postulated as a compound with multiple cytoprotective properties, including antioxidant and anti-inflammatory effects. The aim of the present study was to examine the antioxidant potential of sodium pyruvate (4.5 mM) in vanadyl sulphate (VOSO4)-exposed CHO-K1 cells. Dichloro-dihydro-fluorescein diacetate and dihydrorhodamine 123 staining were performed to measure total and mitochondrial generation of reactive oxygen species (ROS), respectively. Furthermore, mitochondrial damage was investigated using MitoTell orange and JC-10 staining assays. We demonstrated that VOSO4 alone induced a significant rise in ROS starting from 1 h to 3 h after the treatment. Additionally, after 24 and 48 h of exposure, VOSO4 elicited both extensive hyperpolarisation and depolarisation of the mitochondrial membrane potential (MMP). The two-way ANOVA analysis of the results showed that, through antagonistic interaction, pyruvate prevented VOSO4-induced total ROS generation, which could be observed at the 3 h time point. In addition, through the independent action and antagonistic interaction with VOSO4, pyruvate provided a pronounced protective effect against VOSO4-mediated mitochondrial toxicity at 24-h exposure, i.e., prevention of VOSO4-induced hyperpolarisation and depolarisation of MMP. In conclusion, we found that pyruvate exerted cytoprotective effects against vanadium-induced toxicity at least in part by decreasing ROS generation and preserving mitochondrial functions