Decreased Reactive Oxygen Species Production Research Articles

Abstract PO3-25-12: Tigecycline-Induced Metabolic Reprogramming and Cytokine Modulation Suppress the Characteristics of Breast Cancer Cells

Abstract Objective: Patients with advanced breast cancer are prone to recurrence and metastasis. Hence, there is still a need to find new potential drugs or adjuvants to improve prognosis. The Warburg effect, which is highly dependent on glycolysis, has been found to be present in the energy metabolism of tumors, including breast cancer. The effect also promotes the production of cytokines, to adapt the inflammatory microenvironment of tumor. However, drugs targeting Warburg effect and inflammatory environment are rarely reported in the treatment of breast cancer. Tigecycline (Tige) is a commonly used glycylcycline antibiotic. Previous research has indicated it impede mitochondrial oxidative phosphorylation (OXPHOS) in various solid tumors. Based on the team's previous research, our study aimed to investigate whether Tige could inhibit breast cancer development by interfering with the Warburg effect and the inflammatory environment. Methods: MB231, MB468 and MCF7, T47D, which represent triple-negative and estrogen receptor positive breast cancers, were treated with Tige at different concentrations for different periods of time. CCK8, colony formation and sphere formation assays were used to evaluate the effects on proliferation and tumor stemness in vitro, respectively. The effects on migration and invasion were evaluated by wound healing assay and Transwell. RNA sequencing was used to explore the genes altered and analyze the pathways involved. After labeling with probes, the changes of reactive oxygen species (ROS) were detected by fluorescence microscope, microplate reader, and flow cytometry. Cell cycle and apoptosis were detected by flow cytometry. Liquid cytokine chip was used to analyze the secretion of cytokines. Electron microscopy was performed to observe the changes in mitochondrial morphology. RT-PCR was used to detect the expression of rate-limiting enzymes in glycolysis pathway. Glucose consumption, lactate and pyruvate production were measured using glucose, lactate and pyruvate detection kits, respectively. Western blot was used to detect the changes of respiratory chain protein complex and other related pathway proteins in OXPHOS. Results: Four breast cancer cells showed a significant decrease in cell proliferation, invasion and migratory ability after Tige treatment. Sphere-forming assays also showed that Tige had an effect on the stemness of breast cancer. RNA-sequencing showed that glycolysis, cell cycle, and immune-related pathways were inhibited after Tige treatment, and ROS production analysis revealed a decrease in ROS production. Flow cytometry also revealed that the cell cycle was arrested in S phase without significant apoptosis. Cytokine liquid chip analysis showed that the secretion of many cytokines, mainly interleukin (such as IL-1B), was inhibited after Tige intervention. RT-PCR results showed that the expression of several rate-limiting enzymes of the glycolytic pathway decreased. Glucose, lactate and pyruvate assay results showed that Tige reduced glucose uptake and lactate, pyruvate production. Electron microscopy results revealed that mitochondria in Tige treated cells showed significant contractures. WB results also showed a decrease in the expression of OXPHOS-related proteins. However, due to the heterogeneity of the four breast cancer cells, the degree of change in these capacities was not entirely consistent. Conclusions: Tige not only inhibits mitochondrial OXPHOS, but also inhibits the glycolysis pathway, which results in the inhibition of glucose uptake and the production of pyruvate and lactate. The secretion of early pro-inflammatory cytokines also affected. Therefore, this study suggests that Tige may change the glucose metabolism and energy metabolism, and also change the inflammatory environment of breast tumors, which provides new evidence for the anti-tumor effect of Tige in breast cancer. Citation Format: Haochen Yu, Lingfeng Tang, Shengchun Liu. Tigecycline-Induced Metabolic Reprogramming and Cytokine Modulation Suppress the Characteristics of Breast Cancer Cells [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-25-12.

Vincamine alleviates brain injury by attenuating neuroinflammation and oxidative damage in a mouse model of Parkinson's disease through the NF-κB and Nrf2/HO-1 signaling pathways.

Parkinson's disease (PD)is a neurodegenerative disease featured by progressive loss of nigrostriatal dopaminergic neurons, the etiology of which is associated with the existence of neuroinflammatory response and oxidative stress. Vincamine is an indole alkaloid that was reported to exhibit potent anti-inflammatory and antioxidant properties in many central and/or peripheral diseases. Nevertheless, the specific role of vincamine in PD development remains unknown. In our study, dopaminergic neuron loss was determined through immunohistochemistry staining and western blot analysis of tyrosine hydroxylase (TH)expression in the substantia nigra (SN)of PD mice. Reactive oxygen species (ROS)production and malondialdehyde (MDA),superoxide dismutase (SOD),and glutathione (GSH)levels were detected through DHE staining and commercially available kits to assess oxidative stress. Pro-inflammatorycytokine (TNF-α,IL-1β, and IL-6)levels in the SN were measured via RT-qPCRand western blot analysis. Microglial and astrocyte activation was examined through immunofluorescence staining of Iba-1 (microglia marker) and GFAP (astrocyte marker) in the SN. The regulation of vincamine on the NF-κBand Nrf2/HO-1pathway was estimated through western blot analysis. Our results showed that vincamine treatment decreased TNF-α,IL-1β,and IL-6 mRNA and protein levels, reduced GFAP and Iba-1 expression, decreased ROS production and MDA level, and increased SOD activity and GSH level in the SN of PD mice. Mechanically, vincamine repressed the phosphorylation levels of p65, IKKβ, and IκBα but enhanced the protein levels of Nrf2 and HO-1 in PD mice. Collectively, vincamine plays a neuroprotective role in PD mouse models by alleviating neuroinflammation and oxidative damage via suppressing the NF-κBpathway and activating the Nrf2/HO-1pathway.

Proteasome inhibitor bortezomib prevents proliferation and migration of pulmonary arterial smooth muscle cells.

Pulmonary vascular remodeling is a key pathological process of pulmonary arterial hypertension (PAH), characterized by uncontrolled proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs). Bortezomib (BTZ) is the first Food and Drug Administration (FDA)-approved proteasome inhibitor for multiple myeloma treatment. Recently, there is emerging evidence showing its effect on reversing PAH, although its mechanisms are not well understood. In this study, anti-proliferative and anti-migratory effects of BTZ on PASMCs were first examined by different inducers such as fetal bovine serum (FBS), angiotensin II (Ang II) and platelet-derived growth factor (PDGF)-BB, while potential mechanisms including cellular reactive oxygen species (ROS) and mitochondrial ROS were then investigated; finally, signal transduction of ERK and Akt was examined. Our results showed that BTZ attenuated FBS-, Ang II- and PDGF-BB-induced proliferation and migration, with associated decreased cellular ROS production and mitochondrial ROS production. In addition, the phosphorylation of ERK and Akt induced by Ang II and PDGF-BB was also inhibited by BTZ treatment. This study indicates that BTZ can prevent proliferation and migration of PASMCs, which are possibly mediated by decreased ROS production and down-regulation of ERK and Akt. Thus, proteasome inhibition can be a novel pharmacological target in the management of PAH.

TIGAR reduces neuronal ferroptosis by inhibiting succinate dehydrogenase activity in cerebral ischemia

Ischemia Stroke (IS) is an acute neurological condition with high morbidity, disability, and mortality due to a severe reduction in local cerebral blood flow to the brain and blockage of oxygen and glucose supply. Oxidative stress induced by IS predisposes neurons to ferroptosis. TP53-induced glycolysis and apoptosis regulator (TIGAR) inhibits the intracellular glycolytic pathway to increase pentose phosphate pathway (PPP) flux, promotes NADPH production and thus generates reduced glutathione (GSH) to scavenge reactive oxygen species (ROS), and thus shows strong antioxidant effects to ameliorate cerebral ischemia/reperfusion injury. However, in the current study, prolonged ischemia impaired the PPP, and TIGAR was unable to produce NADPH but was still able to reduce neuronal ferroptosis and attenuate ischemic brain injury. Ferroptosis is a form of cell death caused by free radical-driven lipid peroxidation, and the vast majority of ROS leading to oxidative stress are generated by mitochondrial succinate dehydrogenase (SDH) driving reverse electron transfer (RET) via the mitochondrial electron transport chain. Overexpression of TIGAR significantly inhibited hypoxia-induced enhancement of SDH activity, and TIGAR deficiency further enhanced SDH activity. We also found that the inhibitory effect of TIGAR on SDH activity was related to its mitochondrial translocation under hypoxic conditions. TIGAR may inhibit SDH activity by mediating post-translational modifications (acetylation and succinylation) of SDH A through interaction with SDH A. SDH activity inhibition reduces neuronal ferroptosis by decreasing ROS production, eliminating MitoROS levels and attenuating lipid peroxide accumulation. Notably, TIGAR-mediated inhibition of SDH activity and ferroptosis was not dependent on the PPP-NADPH-GPX4 pathways. In conclusion, mitochondrial translocation of TIGAR in prolonged ischemia is an important pathway to reduce neuronal ferroptosis and provide sustainable antioxidant defense for the brain under prolonged ischemia, further complementing the mechanism of TIGAR resistance to oxidative stress induced by IS.

Capsosiphon fulvescens suppresses LPS-stimulated inflammatory responses by suppressing TLR4/NF-κB activation in RAW264.7 murine macrophages

Objective: To evaluate the effects of Capsosiphon fulvescens (C. fulvescens) ethanolic extract on inflammation in lipopolysaccharide (LPS)-induced RAW296.7 macrophages. Methods: The protective effects of C. fulvescens ethanolic extract on LPS-induced inflammation in RAW264.7 macrophages were assessed using biochemical analysis, including enzyme-linked immunosorbent assay, quantitative reverse transcription-polymerase chain reaction, and Western blot analysis. To examine reactive oxygen species (ROS) production, flow cytometry analysis, and immunofluorescence staining were used. Furthermore, the modulatory effect of C. fulvescens ethanolic extract on NF-κB activation was investigated. Results: C. fulvescens ethanolic extract significantly attenuated LPS-induced levels of pro-inflammatory cytokines and notably reduced the secretion and mRNA levels of LPS-mediated matrix metalloproteinases. In addition, C. fulvescens ethanolic extract decreased ROS production and suppressed the TLR4/NF-κB signaling pathway. Conclusions: C. fulvescens ethanolic extract alleviates inflammation as well as oxidative stress by modulating the TLR4/NF-κB signaling in LPS-induced RAW264.7 macrophages. C. fulvescens can be used as a potential therapeutic agent to suppress inflammation and oxidative stress-associated diseases.

Orosomucoid 2 as a biomarker of carotid artery atherosclerosis plaque vulnerability through its generation of reactive oxygen species and lipid accumulation in vascular smooth muscle cells

BackgroundOrosomucoid (ORM) has been reported as a biomarker of carotid atherosclerosis, but the role of ORM 2, a subtype of ORM, in carotid atherosclerotic plaque formation and the underlying mechanism have not been established. MethodsPlasma was collected from patients with carotid artery stenosis (CAS) and healthy participants and assessed using mass spectrometry coupled with isobaric tags for relative and absolute quantification (iTRAQ) technology to identify differentially expressed proteins. The key proteins and related pathways were identified via western blotting, immunohistochemistry, and polymerase chain reaction of carotid artery plaque tissues and in vitro experiments involving vascular smooth muscle cells (VSMCs). ResultsWe screened 33 differentially expressed proteins out of 535 proteins in the plasma. Seventeen proteins showed increased expressions in the CAS groups relative to the healthy groups, while 16 proteins showed decreased expressions during iTRAQ and bioinformatic analysis. The reactive oxygen species metabolic process was the most common enrichment pathway identified by Gene Ontology analysis, while ORM2, PRDX2, GPX3, HP, HBB, ANXA5, PFN1, CFL1, and S100A11 were key proteins identified by STRING and MCODE analysis. ORM2 showed increased expression in patients with CAS plaques, and ORM2 was accumulated in smooth muscle cells. Oleic acid increased the lipid accumulation and ORM2 and PRDX6 expressions in the VSMCs. The recombinant-ORM2 also increased the lipid accumulation and reactive oxygen species (ROS) in the VSMCs. The expressions of ORM2 and PRDX-6 were correlated, and MJ33 (an inhibitor of PRDX6-PLA2) decreased ROS production and lipid accumulation in VSMCs. ConclusionORM2 may be a biomarker for CAS; it induced lipid accumulation and ROS production in VSMCs during atherosclerosis plaque formation. However, the relationships between ORM2 and PRDX-6 underlying lipid accumulation-induced plaque vulnerability require further research.

Reducing Oxidative Stress and Inflammation by Pyruvate Dehydrogenase Kinase 4 Inhibition Is Important in Prevention of Renal Ischemia-Reperfusion Injury in Diabetic Mice.

Reactive oxygen species (ROS) and inflammation are reported to have a fundamental role in the pathogenesis of ischemia-reperfusion (IR) injury, a leading cause of acute kidney injury. The present study investigated the role of pyruvate dehydrogenase kinase 4 (PDK4) in ROS production and inflammation following IR injury. We used a streptozotocin-induced diabetic C57BL6/J mouse model, which was subjected to IR by clamping both renal pedicles. Cellular apoptosis and inflammatory markers were evaluated in NRK-52E cells and mouse primary tubular cells after hypoxia and reoxygenation using a hypoxia work station. Following IR injury in diabetic mice, the expression of PDK4, rather than the other PDK isoforms, was induced with a marked increase in pyruvate dehydrogenase E1α (PDHE1α) phosphorylation. This was accompanied by a pronounced ROS activation, as well as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and monocyte chemoattractant protein-1 (MCP-1) production. Notably, sodium dichloroacetate (DCA) attenuated renal IR injury-induced apoptosis which can be attributed to reducing PDK4 expression and PDHE1α phosphorylation levels. DCA or shPdk4 treatment reduced oxidative stress and decreased TNF-α, IL-6, IL-1β, and MCP-1 production after IR or hypoxia-reoxygenation injury. PDK4 inhibition alleviated renal injury with decreased ROS production and inflammation, supporting a critical role for PDK4 in IR mediated damage. This result indicates another potential target for reno-protection during IR injury; accordingly, the role of PDK4 inhibition needs to be comprehensively elucidated in terms of mitochondrial function during renal IR injury.

P064 Investigating the genotoxic effect of reduced glutathione, n-acetylcysteine, human umbilical cord-derived mesenchymal stem cell exosomes and let-7 miRNA mimics in human lymphocytes and EpiIntestinal cells

Abstract Background The current treatments for IBD frequently do not provide sufficient control over the disease, warranting the investigation of alternative therapeutic options with minimal risk of side effects. In IBD, the overgeneration and insufficient removal of reactive oxygen species (ROS) leads to oxidative stress. Reduced glutathione (GSH) and n-acetylcysteine (NAC) are antioxidants which may possess therapeutic potential in IBD, by modulating endogenous mechanisms that decrease ROS production or increase antioxidant enzymes. Additonally, exosomes from human umbilical cord blood derived mesenchymal stem cells (hucMSCs-exo) may be used to treat IBD. These are a subset of extracellular nanosized membrane vesicles which participate in intercellular communication by delivering their contents, such as functional miRNAs to recipient cells, thereby influencing the physiological and pathological processes in various diseases. The therapeutic potential of exosomes can be enhanced through the overexpression of the let-7 family of miRNAs. Methods The EpiIntestinal tissue model is a physiologically relevant predictor of drug-induced GI toxicity. EpiIntestinal cells and lymphocytes from 3 IBD patients were transfected with 50 μL miRNA mimics and inhibitors, and treated with 50μL hucMSC-exo, and 50 μL 1mM GSH and NAC. Next, in comparison to negative controls, single-stranded DNA damage was assessed in peripheral blood mononuclear cells (PBMCs) from IBD patients using the fast microplate DNA damage assay, and double-stranded DNA damage was assessed in EpiIntestinal cells using the alkaline Comet assay. In addition, the viability of healthy and IBD lymphocytes was assessed following treatment with selected concentrations of hucMSC-exo, GSH and NAC. Results Double-stranded DNA damage was significantly reduced in EpiIntestinal cells compared to the negative control following treatment with hucMSC-exo, GSH, NAC, and miRNA mimics for let-7a-5p, -7b-5p, -7c-3p, -7d-3p and -7d-5p. In addition, single-stranded DNA damage was reduced in IBD PBMCs compared to the negative control following treatment with hucMSC-exo, and let-7b-5p and -7c-3p mimics, but was increased following treatment with inhibitors for let-7b-5p, -7c-5p and two novel miRNAs. Additionally, GSH, NAC and hucMSC-exo increased cell viability in treated versus untreated lymphocytes from healthy individuals and IBD patients. Conclusion Selected concentrations of HucMSC-exo, GSH, NAC and/or let-7 miRNA mimics reduced DNA damage and increased cell viability in treated versus untreated cells which may reduce the risk of colorectal cancer in IBD patients. Acknowledgements Our gratitude goes to the MatTek Team for generously granting us a SMI-100-FT EpiIntestinal kit in support of this research.

Pharmacological Activation of AMPK Prevents Drp1-mediated Mitochondrial Fission and Alleviates Hepatic Steatosis In vitro.

The incidence of non-alcoholic fatty liver disease (NAFLD) is increasing worldwide. Adenosine monophosphate-activated protein kinase (AMPK) activation is beneficial for NAFLD treatment. Recent studies show the excessive fission of mitochondria during NAFLD progression, so targeting mitochondria dynamics may be a possible target for NAFLD. Still, little is known about whether AMPK regulates mitochondrial dynamics in hepar. This study investigated whether AMPK activation alleviates hepatic steatosis by regulating mitochondrial dynamics mediated by GTPase dynamin-related protein 1 (Drp1). Human hepatocyte line L-02 cells were cultured and subjected to palmitic acid (PA) treatment for 24 h to establish a hepatic steatosis model in vitro, which was pre-treated with different tool drugs. Hepatocyte function, hepatocyte lipid content, mitochondrial reactive oxygen species (ROS) production, and mitochondrial membrane potential (MMP) were examined. The expression levels of genes and proteins associated with mitochondrial dynamics were assessed using reverse transcription-quantitative PCR and western blotting. The results indicated that 5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR), an AMPK activator, improved hepatocyte function, as demonstrated by decreased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity (P＜0.05 or P＜0.01). In addition, AICAR decreased total cholesterol (TC) and triglyceride (TG) content and lipid deposition in hepatocytes (P＜0.01); decreased ROS production; improved MMP (P＜0.01); reduced fission-1 (Fis1) and mitochondrial fission factor (Mff) mRNA expression; and downregulated p-Drp1 (Ser 616) protein expression. In contrast, AICAR increased mitochondrial fusion factor mitofusin-1 (Mfn1) and mitofusin-2 (Mfn2) mRNA expression and upregulated p-Drp1 (Ser 637) protein expression. Mdivi-1, a Drp-1 inhibitor, was used to confirm whether mitochondrial dynamics regulated by Drp1-mediated the role of AICAR. Similar to AICAR, Mdivi-1 improved hepatocyte function and MMP significantly, decreased ROS production and lipid deposition, downregulated Fis1 and Mff mRNA expression, downregulated p-Drp1 (Ser 616) protein expression, and enhanced Mfn1 and Mfn2 mRNA and p-Drp1 (Ser 637) protein expression. However, Compound C, an AMPKspecific inhibitor, had less impact on the protective effect of Mdivi-1. The results demonstrated that AMPK activation has a protective effect on hepatic steatosis in vitro, largely dependent on the inhibition of Drp1-mediated mitochondrial fission.

The alleviative effect of C-phycocyanin peptides against TNBS-induced inflammatory bowel disease in zebrafish via the MAPK/Nrf2 signaling pathways

IntroductionUlcerative colitis (UC) is an incurable and highly complex chronic inflammatory bowel disease (IBD) affecting millions of people worldwide. C-phycocyanin (C-PC) has been reported to possess outstanding anti-inflammatory activities and can effectively inhibit various inflammation-related diseases. Whether C-PC-derived bioactive peptides can inhibit intestinal inflammation is worth research and consideration. MethodsThe inhibition activities of three anti-neuroinflammatory peptides were evaluated using 2-4-6-trinitrobenzen sulfonic acid (TNBS)-induced zebrafish colitis model. Subsequently, the abilities of peptides to promote gastrointestinal motility were also examined. The changes in the intestinal pathological symptoms and ultrastructure of intestinal, reactive oxygen species (ROS) levels, and antioxidant enzymes were then determined after co-treatment with peptides and TNBS. Transcriptome analysis was used to investigate the underlying ameliorating TNBS-induced colitis effects molecular mechanisms of better activity peptide. Furthermore, quantitative reverse-transcription polymerase chain reaction and molecular docking techniques verified the mRNA sequencing results. ResultsThree peptides, MHLWAAK, MAQAAEYYR and MDYYFEER, which significantly inhibit macrophage migration, were synthesized. The results showed that these peptides could effectively alleviate the inflammatory responses in the TNBS-induced zebrafish model of colitis. In addition, co-treatment with TNBS and C-PC peptides could decrease ROS production and increase antioxidant enzyme activities in zebrafish larvae. Moreover, MHLWAAK had the most significantly therapeutic effects on colitis in zebrafish. The transcriptome analysis suggests that the effect of MHLWAAK on TNBS-induced colitis may be associated with the modulation of nuclear factor-erythroid 2-related factor 2 (Nrf2) and mitogen-activated protein kinase (MAPK) signaling pathway associated genes. In addition, molecular docking was conducted to study the prospective interaction between peptides and the key proteins that streamline the Nrf2 and MAPK signaling pathways. IL-6, JNK3, TNF-α, KEAP1-NRF2 complex and MAPK may be the core targets of MHLWAAK in treating colitis. ConclusionThe results suggested that the three C-PC-derived peptides could ameliorate TNBS-induced colitis in zebrafish, and these peptides might be a promising therapeutic candidate for UC treatment.

Exploring the Therapeutic Potential of Ampelopsis grossedentata Leaf Extract as an Anti-Inflammatory and Antioxidant Agent in Human Immune Cells.

Inflammation is a vital protective response to threats, but it can turn harmful if chronic and uncontrolled. Key elements involve pro-inflammatory cells and signaling pathways, including the secretion of pro-inflammatory cytokines, NF-κB, reactive oxygen species (ROS) production, and the activation of the NLRP3 inflammasome. Ampelopsis grossedentata, or vine tea, contains dihydromyricetin (DHM) and myricetin, which are known for their various health benefits, including anti-inflammatory properties. Therefore, the aim of this study is to assess the impact of an extract of A. grossedentata leaves (50 µg/mL) on inflammation factors such as inflammasome, pro-inflammatory pathways, and macrophage polarization, as well as its antioxidant properties, with a view to combating the development of low-grade inflammation. Ampelopsis grossedentata extract (APG) significantly decreased ROS production and the secretion of pro-inflammatory cytokines (IFNγ, IL-12, IL-2, and IL-17a) in human leukocytes. In addition, APG reduced LPS/IFNγ -induced M1-like macrophage polarization, resulting in a significant decrease in the expression of the pro-inflammatory cytokines TNF-α and IL-6, along with a decrease in the percentage of M1 macrophages and an increase in M0 macrophages. Simultaneously, a significant decrease in NF-κB p65 phosphorylation and in the expression of inflammasome genes (NLRP3, IL-1β and Caspase 1) was observed. The results suggest that Ampelopsis grossedentata could be a promising option for managing inflammation-related chronic diseases. Further research is needed to optimize dosage and administration methods.

Regulator of G protein signaling protein 6 alleviates acute lung injury by inhibiting inflammation and promoting cell self-renewal in mice

BackgroundAcute respiratory distress syndrome (ARDS) is a disease with high mortality and morbidity. Regulator of G protein signaling protein 6 (RGS6), identified as a tumor suppressor gene, has received increasing attention owing to its close relationship with oxidative stress and inflammation. However, the association between ARDS and RGS6 has not been reported.MethodsCongruously regulated G protein-coupled receptor (GPCR)-related genes and differentially expressed genes (DEGs) in an acute lung injury (ALI) model were identified, and functional enrichment analysis was conducted. In an in vivo study, the effects of RGS6 knockout were studied in a mouse model of ALI induced by lipopolysaccharide (LPS). HE staining, ELISA, and immunohistochemistry were used to evaluate pathological changes and the degree of inflammation. In vitro, qRT‒PCR, immunofluorescence staining, and western blotting were used to determine the dynamic changes in RGS6 expression in cells. The RGS6 overexpression plasmid was constructed for transfection. qRT‒PCR was used to assess proinflammatory factors transcription. Western blotting and flow cytometry were used to evaluate apoptosis and reactive oxygen species (ROS) production. Organoid culture was used to assess the stemness and self-renewal capacity of alveolar epithelial type II cells (AEC2s).ResultsA total of 110 congruously regulated genes (61 congruously upregulated and 49 congruously downregulated genes) were identified among GPCR-related genes and DEGs in the ALI model. RGS6 was downregulated in vivo and in vitro in the ALI model. RGS6 was expressed in the cytoplasm and accumulated in the nucleus after LPS stimulation. Compared with the control group, we found higher mortality, more pronounced body weight changes, more serious pulmonary edema and pathological damage, and more neutrophil infiltration in the RGS6 knockout group upon LPS stimulation in vivo. Moreover, AEC2s loss was significantly increased upon RGS6 knockout. Organoid culture assays showed slower alveolar organoid formation, fewer alveolar organoids, and impaired development of new structures after passaging upon RGS6 knockout. In addition, RGS6 overexpression decreased ROS production as well as proinflammatory factor transcription in macrophages and decreased apoptosis in epithelial cells.ConclusionsRGS6 plays a protective role in ALI not only in early inflammatory responses but also in endogenous lung stem cell regeneration.Graphical

Effects of Hyperthermia and Acidosis on Mitochondrial Production of Reactive Oxygen Species.

Exercise is associated with the development of oxidative stress, but the specific source and mechanism of production of pro-oxidant chemicals during exercise has not been confirmed. We used equine skeletal muscle mitochondria to test the hypothesis that hyperthermia and acidosis affect mitochondrial oxygen consumption and production of reactive oxygen species (ROS). Skeletal muscle biopsies were obtained at rest, after an acute episode of fatiguing exercise, and after a 9-week conditioning program to increase aerobic fitness. Mitochondrial oxygen consumption and ROS production were measured simultaneously using high-resolution respirometry. Both hyperthermia and acidosis increased non-phosphorylating (LEAK) respiration (5.8X and 3.0X, respectively, p<0.001) and decreased efficiency of oxidative phosphorylation. The combined effects of hyperthermia and acidosis resulted in large decreases in phosphorylating respiration, further decreasing oxidative phosphorylation efficiency from 97% to 86% (p<0.01). Increased aerobic fitness reduced the effects of acidosis on LEAK respiration. Hyperthermia increased, and acidosis decreased ROS production (2X and 0.23X, respectively, p<0.001). There was no effect of acute exercise, but an aerobic conditioning program was associated with increased ROS production during both non-phosphorylating and phosphorylating respiration. Hyperthermia increased the ratio of ROS production to O2 consumption during phosphorylating respiration, suggesting that high temperature impaired transfer of energy through the electron transfer system despite relatively low mitochondrial membrane potential. These data support the role of skeletal muscle mitochondria in the development of exercise-induced oxidative stress, particularly during forms of exercise that result in prolonged hyperthermia without acidosis.

Resveratrol Reduces ROS by Increasing GSH in Vitrified Sheep Embryos

The in vitro production and cryopreservation of mammalian embryos generates reactive oxygen species (ROS) due to conditions of the system that can overcome their antioxidant protection. Resveratrol is an antioxidant used in in vitro systems to improve blastocyst rates, but its effect on antioxidant enzymes such as glutathione (GSH) in embryos produced by in vitro fertilization (IVF) after vitrification has not been reported. The objective of this study was to evaluate the effects of resveratrol on the in vitro maturation medium (IVM) of sheep oocytes (Ovis aries) on the levels of ROS and GSH in embryos produced by IVF subjected to vitrification. Resveratrol was added at 0 µM, 0.25 µM, 0.5 µM, and 1 µM during oocyte in vitro maturation (IVM). Matured oocytes were fertilized with thawed ram sperm. Embryos were cultured in sequential media until blastocysts, were then vitrified for 24 h, and, after heating, they were stained with DCFH-DA (2′,7′-dichlorodihydrofluorescein diacetate) to determine the presence of ROS and with Cell Tracker Blue® for the presence of GSH. The quantitative values of ROS and GSH were obtained through the Image J image processor. The results showed that resveratrol increased GSH and decreased ROS production (p &lt; 0.05) in a dose-dependent manner. It is concluded that its use in sheep oocytes during IVM has a beneficial effect on embryos produced by IVF subjected to vitrification by decreasing reactive oxygen species levels and facilitating the generation of embryo antioxidant enzymes like glutathione.

A comparison of Jasmonic acid and salicylic acid-induced salinity stress tolerance in safflower plants, particularly on sodium (Na) and potassium (K) nutrient contents

Jasmonic acid (JA) and salicylic acid (SA) are phytohormones that have a significant role in the induction of plant defense against different stress factors. The role of these phytohormones was assessed on several physicochemical properties of safflower plants subjected to salinity. JA and, especially SA, caused plants had more Na+ and less K+ content compared with the control plants. The JA and SA increased the catalase (CAT) activity, whereas significantly decreased the reactive oxygen species (ROS) production and lipid peroxidation in safflower plants under salinity stress. No significant effects of phytohormones were observed on peroxidase (POD) and ascorbate peroxidase (APX) activities in safflower plants exposed to salinity stress. Data on plant fluorescence indicated that seed priming with JA and SA decreases ROS production in photosystems. The effect of JA and SA under salinity stress was observed to significantly influence the light-dependent phase (J-I and I-P phases of chlorophyll a fluorescence curve) in comparison to the rest of the electron transport chain in safflower plants. This finding was supported by the high improvement of quantum yield of reduction of the end electron acceptors at the photosystem I acceptor side (φRo) activity under severe salinity stress. The observation indicated that the SA treatment was more effective in safflower plants exposed to salinity stress in comparison to the JA treatment.

Uncoupling protein 2 modulates polarization and metabolism of human primary macrophages via glycolysis and the NF‑κB pathway.

Metabolic abnormalities, particularly the M1/M2 macrophage imbalance, play a critical role in the development of various diseases, leading to severe inflammatory responses. The present study aimed to investigate the role of uncoupling protein 2 (UCP2) in regulating macrophage polarization, glycolysis, metabolic reprogramming, reactive oxygen species (ROS) and inflammation. Primary human macrophages were first polarized into M1 and M2 subtypes, and these two subtypes were infected by lentivirus-mediated UCP2 overexpression or knockdown, followed by enzyme-linked immunosorbent assay, reverse transcription-quantitative PCR, western blotting and flow cytometry to analyze the effects of UCP2 on glycolysis, oxidative phosphorylation (OXPHOS), ROS production and cytokine secretion, respectively. The results demonstrated that UCP2 expression was suppressed in M1 macrophages and increased in M2 macrophages, suggesting its regulatory role in macrophage polarization. UCP2 overexpression decreased macrophage glycolysis, increased OXPHOS, decreased ROS production, and led to the conversion of M1 polarization to M2 polarization. This process involved NF-κB signaling to regulate the secretion profile of cytokines and chemokines and affected the expression of key enzymes of glycolysis and a key factor for maintaining mitochondrial homeostasis (nuclear respiratory factor 1). UCP2 knockdown in M2 macrophages exacerbated inflammation and oxidative stress by promoting glycolysis, which was attenuated by the glycolysis inhibitor 2-deoxyglucose. These findings highlight the critical role of UCP2 in regulating macrophage polarization, metabolism, inflammation and oxidative stress through its effects on glycolysis, providing valuable insights into potential therapeutic strategies for macrophage-driven inflammatory and metabolic diseases.

Dexmedetomidine Preconditioning Attenuates Myocardial Ischemia/Reperfusion Injury in Rats by Suppressing Mitophagy Via Activating Α2-Adrenergic Receptor.

Dexmedetomidine (DEX), a specific α2-adrenergic receptor agonist, is protective against myocardial ischemia/reperfusion injury (MIRI). However, the association between DEX preconditioning-induced cardioprotection and mitophagy suppression remains unclear. Hence, we aimed to investigate whether DEX preconditioning alleviates MIRI by suppressing mitophagy via α2-adrenergic receptor activation. Sixty isolated rat hearts were treated with or without DEX before inducing ischemia and reperfusion; an α2-adrenergic receptor antagonist, yohimbine (YOH), was also administered before ischemia, alone or with DEX. The heart rate (HR), left ventricular diastolic pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), maximal and minimal rate of left ventricular pressure development (±dp/dtmax), and myocardial infarction size were measured. The mitochondrial ultrastructure and autophagosomes were assessed using transmission electron microscopy. Mitochondrial membrane potential and reactive oxygen species (ROS) levels were measured using JC-1 and dichloride hydrofluorescein diacetate assays, respectively. The expression levels of the mitophagy-associated proteins Beclin1, LC3II/I ratio, p62, PINK1, and Parkin were detected by western blotting. Compared with the control group, in the ischemia/reperfusion group, the HR, LVDP, and ±dp/dtmax were remarkably decreased (p< 0.05), whereas LVEDP and infarct sizes were significantly increased (p< 0.05). DEX preconditioning significantly improved cardiac dysfunction reduced myocardial infarction size, maintained mitochondrial structural integrity, increased mitochondrial membrane potential, inhibited autophagosomes formation, and decreased ROS production and Beclin1, LC3II/I ratio, PINK1, Parkin, and p62 expression(p< 0.05). When DEX and YOH were combined, YOH canceled the effect of DEX, whereas the use of YOH alone had no effect. Therefore, DEX preconditioning was cardioprotective against MIRI in rats by suppressing mitophagy via α2-adrenergic receptor activation.

Assessment of the Antioxidant Properties of Horned Turban (Turbo cornutus) Viscera, Marine By-Products with Potential Application in Nutraceuticals

Horned turban (Turbo cornutus) is an edible gastropod that occurs along the intertidal zone and basalt coastline, and is an important marine resource in Jeju, Korea. However, T. cornutus viscera are mostly discarded following processing. In this study, the antioxidant activity of viscera and muscle extracts was compared. In addition, the protective effect of T. cornutus viscera ethanol extract (TVEE) against H2O2-induced oxidative stress in human dermal fibroblasts (HDFs) was investigated. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and hydrogen peroxide scavenging activity of the viscera (IC50 = 0.64 ± 0.64 and 0.76 ± 0.01 mg/mL, respectively) showed higher activity than that in muscle. TVEE increased the reactive oxygen species (ROS) scavenging effect and cell viability in H2O2-induced HDFs without cytotoxicity. Furthermore, the fluorescence intensity of HDFs was high in those from H2O2-induced intracellular ROS production, but TVEE treatment decreased ROS production. H2O2 activated the mitogen-activated protein kinase (MAPK) signaling and matrix metalloproteinase 2 (MMP-2) in HDFs. However, MMP2 expression was confirmed to be reduced via MAPK (ERK, JNK, and p38) signaling phosphorylation. In conclusion, various antioxidant effects were confirmed in T. cornutus viscera, which instead of being discarded as marine by-products, can be applied as nutraceuticals in various industries.

Retinoic acid loaded with chitosan nanoparticles improves spermatogenesis in scrotal hyperthermia in mice.

High temperatures can trigger cellular oxidative stress and disrupt spermatogenesis, potentially leading to male infertility. We investigated the effects of retinoic acid (RA), chitosan nanoparticles (CHNPs), and retinoic acid loaded with chitosan nanoparticles (RACHNPs) on spermatogenesis in mice induced by scrotal hyperthermia (Hyp). Thirty mice (weighing 25 to 30 g) were divided into five experimental groups of six mice each. The groups were as follows: control, Hyp induced by a water bath (43 °C for 30 minutes/day for 5 weeks), Hyp+RA (2 mg/kg/day), Hyp+CHNPs (2 mg/kg/72 hours), and Hyp+RACHNPs (4 mg/kg/72 hours). The mice were treated for 35 days. After the experimental treatments, the animals were euthanized. Sperm samples were collected for analysis of sperm parameters, and blood serum was isolated for testosterone measurement. Testis samples were also collected for histopathology assessment, reactive oxygen species (ROS) evaluation, and RNA extraction, which was done to compare the expression levels of the bax, bcl2, p53, Fas, and FasL genes among groups. Additionally, immunohistochemical staining was performed. Treatment with RACHNPs significantly increased stereological parameters such as testicular volume, seminiferous tubule length, and testicular cell count. Additionally, it increased testosterone concentration and improved sperm parameters. We observed significant decreases in ROS production and caspase-3 immunostaining in the RACHNP group. Moreover, the expression levels of bax, p53, Fas, and FasL significantly decreased in the groups treated with RACHNPs and RA. RACHNPs can be considered a potent antioxidative and antiapoptotic agent for therapeutic strategies in reproductive and regenerative medicine.

PD98059 protects SH-SY5Y cells against oxidative stress in oxygen-glucose deprivation/reperfusion.

Mitochondria play a key role in the cerebral ischemia-reperfusion injury. Although the extracellular signal-regulated kinase 1/2 inhibitor PD98059 (PD) is a selective and reversible flavonoid that can protect the mitochondria in a rat model of cardiac arrest/cardiopulmonary resuscitation, its role requires further confirmation. In this study, we investigated whether PD could maintain mitochondrial homeostasis and decrease reactive oxygen species (ROS) production in neuroblastoma (SH-SY5Y) cells exposed to oxygen-glucose deprivation/reperfusion (OGD/R). PD improved the mitochondrial morphology and function, reversed the increase in ROS production and cell apoptosis, and reduced total-superoxide dismutase and Mn-superoxide dismutase activities induced by OGD/R. PD decreases ROS production and improves mitochondrial morphology and function, protecting SH-SY5Y cells against OGD/R-induced injury.