H2O2-induced Injury Research Articles

Baicalin Attenuates H2O2-Induced Oxidative Stress by Regulating the AMPK/Nrf2 Signaling Pathway in IPEC-J2 Cells.

Oxidative stress can adversely affect the health status of the body, more specifically by causing intestinal damage by disrupting the permeability of the intestinal barrier. This is closely related to intestinal epithelial cell apoptosis caused by the mass production of reactive oxygen species (ROS). Baicalin (Bai) is a major active ingredient in Chinese traditional herbal medicine that has antioxidant, anti-inflammatory, and anti-cancer properties. The purpose of this study was to explore the underlying mechanisms by which Bai protects against hydrogen peroxide (H2O2)-induced intestinal injury in vitro. Our results indicated that H2O2 treatment caused injury to IPEC-J2 cells, resulting in their apoptosis. However, Bai treatment attenuated H2O2-induced IPEC-J2 cell damage by up-regulating the mRNA and protein expression of ZO-1, Occludin, and Claudin1. Besides, Bai treatment prevented H2O2-induced ROS and MDA production and increased the activities of antioxidant enzymes (SOD, CAT, and GSH-PX). Moreover, Bai treatment also attenuated H2O2-induced apoptosis in IPEC-J2 cells by down-regulating the mRNA expression of Caspase-3 and Caspase-9 and up-regulating the mRNA expression of FAS and Bax, which are involved in the inhibition of mitochondrial pathways. The expression of Nrf2 increased after treatment with H2O2, and Bai can alleviate this phenomenon. Meanwhile, Bai down-regulated the ratio of phosphorylated AMPK to unphosphorylated AMPK, which is indicative of the mRNA abundance of antioxidant-related genes. In addition, knockdown of AMPK by short-hairpin RNA (shRNA) significantly reduced the protein levels of AMPK and Nrf2, increased the percentage of apoptotic cells, and abrogated Bai-mediated protection against oxidative stress. Collectively, our results indicated that Bai attenuated H2O2-induced cell injury and apoptosis in IPEC-J2 cells through improving the antioxidant capacity through the inhibition of the oxidative stress-mediated AMPK/Nrf2 signaling pathway.

Discovery of myrsinane-type Euphorbia diterpene derivatives through a skeleton conversion strategy from lathyrane diterpene for the treatment of Alzheimer's disease

A series of novel myrsinane-type Euphorbia diterpene derivatives (1–37) were synthesized from the abundant natural lathyrane-type Euphorbia factor L3, using a multi-step chemical process guided by a bioinspired skeleton conversion strategy, with the aim of discovering potential anti-Alzheimer's disease (AD) bioactive lead compounds. The synthesis process involved a concise reductive olefin coupling reaction through an intramolecular Michael addition with a free radical, followed by a visible-light-triggered regioselective cyclopropane ring-opening. The cholinesterase inhibitory and neuroprotective activities of the synthesized myrsinane derivatives were evaluated. Most of the compounds showed moderate to strong potency, highlighting the importance of ester groups in Euphorbia diterpene. In particular, derivative 37 displayed the most potent acetylcholinesterase (AChE) inhibition, with an IC50 value of 8.3 μM, surpassing that of the positive control, tacrine. Additionally, 37 also showed excellent neuroprotective effect against H2O2-induced injury in SH-SY5Y cells, with a cell viability rate of 124.2% at 50 μM, which was significantly higher than that of the model group (viability rate 52.1%). Molecular docking, reactive oxygen species (ROS) analysis, immunofluorescence, and immunoblotting were performed to investigate the mechanism of action of myrsinane derivative 37. The results indicated that derivative 37 may be a promising myrsinane-type multi-functional lead compound for the treatment of Alzheimer's disease. Furthermore, a preliminary SAR analysis was performed to study the acetylcholinesterase inhibitory and neuroprotective activities of these diterpenes.

Protective Effect of Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Pomace Wine on Oxidative Stress of Hydrogen Peroxide by Regulating Keap1/Nrf2 Pathway in HepG2 Cells.

Chinese bayberry (Myrica rubra Sieb. et Zucc.) pomace wine (CPW) is fruity and rich in bioactive compounds, with high nutritional value and antioxidant activities. This study aims to investigate the protective effect of CPW on the oxidative damage induced by hydrogen peroxide in human hepatocellular carcinoma (HepG2) cells and CPW's possible underlying mechanism. The fluorescence assay results revealed that CPW pre-treatment inhibited intracellular reactive oxygen species (ROS) accumulation in H2O2-induced HepG2 cells and cell membrane injury. Meanwhile, CPW remarkably enhanced the activity of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and the content of glutathione (GSH). Moreover, CPW pretreatment significantly regulated the expression of Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway-associated genes (Keap1, Nrf2, NADPH quinone oxidoreductase I (NQO1), and heme oxygenase-1 (HO-1)) and its downstream antioxidant genes (SOD, CAT, GSH, and the glutamate-cysteine ligase catalytic (GCLC) subunit) in HepG2 cells. These data demonstrated that CPW prevented H2O2-induced oxidative stress by regulating the Keap1/Nrf2 signaling pathway.

Lycopene alleviates oxidative stress-induced cell injury in human vascular endothelial cells by encouraging the SIRT1/Nrf2/HO-1 pathway

ABSTRACT Background and objective: Epidemiological research have displayed that dietary intake rich in lycopene, an antioxidant, is negatively correlated with the risk of cardiovascular disease (CVD). This study aimed to investigate whether the intervention with different concentrations of lycopene could attenuate H2O2-induced oxidative stress injury in human vascular endothelial cells (VECs). Methods: The human VECs HMEC-1 and ECV-304 were incubated with a final concentration of 300 µmol/L H2O2, followed by they were incubated with lycopene at doses of 0.5, 1, or 2 µm. Subsequently, cell proliferation, cytotoxicity, cell adhesion, reactive oxygen species (ROS) contents, adhesion molecule expression, oxidative stress levels, pro-inflammatory factor production, the apoptosis protein levels, and the silent information regulator-1 (SIRT1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway protein levels were tested by CCK-8 kit, lactate dehydrogenase (LDH) kit, immunofluorescence labeling, cell surface enzyme immunoassays (EIA), enzyme-linked immunosorbent assay (ELISA), as well as Western blot assays, respectively. Results: Under H2O2 stimulation, HMEC-1 and ECV-304 cell proliferation and the SIRT1/Nrf2/HO-1 pathway protein expression were significantly reduced, whereas cytotoxicity, apoptosis, cell adhesion molecule expression, pro-inflammatory and oxidative stress factors production were apparently encouraged, which were partially countered by lycopene intervention in a dose-dependent manner. Conclusion: Lycopene alleviates H2O2-induced oxidative damage in human VECs by reducing intracellular ROS levels, inflammatory factor production, cell adhesiveness, and apoptosis rate under oxidative stress conditions through activation of the SIRT1/Nrf2/HO-1 pathway.

Polysaccharides extracted from mulberry fruits (Morus nigra L.): antioxidant effect of ameliorating H2O2-induced liver injury in HepG2 cells

BackgroundMori Fructus is an economical and readily available traditional Chinese medicine and food. Polysaccharides in Mori Fructus have clear antioxidant activity and have been found to alleviate oxidative stress (OS)-induced liver damage in experimental studies. The mechanism of regulation of cellular antioxidant activity by mulberry polysaccharides has been suggested to be Nrf2, but it is not clear whether the Nrf2 pathway is mediated by activation of other targets, and the exact process of effects in hepatocytes has yet to be elucidated.MethodsIn this study, the basic characterization of total polysaccharides extracted from mulberry fruits (Morus nigra Linn.) was analyzed. A model of oxidative damage induced by H2O2 in HepG2 cells was established. The levels of cellular oxidation-related markers, including ROS, SOD and Gpx, were then examined. Furthermore, Q-PCR and Western-blot were used to detect the expression of genes and proteins related to the PI3K/Akt-mediated Nrf2 signaling pathway.ResultsThe results showed that a total mulberry polysaccharides (TMP) has a molecular weight of 57.5 kDa with a pyranose ring mainly composed of glucose (48.81%), galactose (22.79%) and mannose (18.2%). TMP reduced the accumulation of ROS in HepG2 cells after H2O2 treatment and modulated the activity of SOD and Gpx. Q-PCR and Western-blot showed that TMP could up-regulate the expression of p-PI3K, p-AKT, Nrf2, NQO1 and HO-1.ConclusionsThis study demonstrates that TMP can reduce ROS accumulation in H2O2-treated HepG2 cells and restore cell viability by activating the PI3K/AKT-mediated Nrf2 pathway. TMP may be a potent antioxidant agent that could slow down oxidative damage to the liver.

Resveratrol Attenuates Hydrogen Peroxide-induced Injury of Rat Ovarian Granulosa-lutein Cells by Resisting Oxidative Stress via the SIRT1/Nrf2/ARE Signaling Pathway.

This paper aims to reveal the molecular mechanism of resveratrol against oxidative stress and cell injury. The ovarian granulosa-lutein cell injury and apoptosis induced by oxidative stress may be responsible for female luteal phase deficiency. The antioxidant function of resveratrol has been confirmed; however, its effect on the expression of antioxidant enzymes and regulatory mechanisms in ovarian granulosa-lutein cells remains unclear. This study aimed to investigate the role of the SIRT1/Nrf2/ARE signaling pathway in the effect of resveratrol on the hydrogen peroxide-induced injury of rat ovarian granulosa-lutein cells. In this study, ovarian granulosa-lutein cells extracted from 3-week female SD rats were treated with 200 μM H2O2 in the presence or absence of 20 μM resveratrol. siRNA-SIRT1 and siRNA-Nrf2 were used to inhibit the expression of SIRT1 and Nrf2, respectively. Cell counting kit 8 (CCK-8), cellular morphology, progesterone secretion, and estradiol were used to evaluate cell injury. Hoechst 33258 staining was used to measure cell apoptosis. DHE staining, DCFH-DA staining, malondialdehyde content, protein carbonyl content, total antioxidant capacity and SOD viability were used to estimate the levels of oxidative stress. Western blot analysis was used to detect the levels of apoptosis-related proteins, and SIRT1/Nrf2/ARE signaling pathway-related proteins. The H2O2 treatment-induced rat ovarian granulosa-lutein cells injury was shown as decreased cell viability, impaired cellular morphology, and decreased levels of progesterone and estradiol. The H2O2 treatment also exacerbated cell apoptosis demonstrated as more apoptotic cells stained by Hoechst staining, decreased level of anti-apoptosis protein Bcl-2 and increased level of pro-apoptosis protein Bax. These effects of cell injury and apoptosis induced by H2O2 can be ameliorated by resveratrol. Resveratrol also alleviated oxidative stress induced by H2O2, supported by decreased superoxide anion and cellular total ROS, decreased malondialdehyde and protein carbonyl levels, and increased total antioxidant capacity and SOD viability. Western blot results demonstrated resveratrol reversed the H2O2-induced decrease in levels of antioxidant enzymes containing ARE sequences and activated SIRT1/Nrf2 pathway. Further treatment by siRNA-Nrf2 suggested resveratrol could not activate the expression of antioxidant enzymes under a condition of inhibition of Nrf2. This study demonstrates that resveratrol attenuated oxidative stress to protect H2O2-induced rat ovarian granulosa-lutein cell injury and apoptosis via SIRT1/Nrf2/ARE signaling pathway.

Hypoglycemic and H2O2-induced oxidative injury protective effects and the phytochemical profiles of the ethyl acetate fraction from Radix Paeoniae Alba.

Radix Paeonia Alba (RPA) is often used as food and medicine. This study aimed to enrich and identify the antioxidant and hypoglycemic bioactive compounds from RPA. The results indicated that the ethyl acetate fraction (EAF) showed the highest total phenolic content, DPPH, ABTS+ scavenging ability, and α-glucosidase inhibition ability (IC50 = 7.27 μg/ml). The EAF could alleviate H2O2-induced oxidative stress in HepG2 cells by decreasing the MDA and ROS levels, improving cell apoptosis, increasing the enzyme activity of GPX-Px, CAT, SOD, Na+/K+-ATP, and Ca2+/Mg2+-ATP, and stimulating T-AOC expression, which also enhanced the glucose uptake of insulin-resistant HepG2 cells. In addition, the EAF significantly reduced the fasting blood glucose level and improved glucose tolerance in diabetic mice. An HPLC-QTOF-MS/MS analysis displayed that procyanidin, digallic acid isomer, methyl gallate, tetragalloylglucose isomer, dimethyl gallic acid, and paeoniflorin were the major compounds in the EAF. These findings are meaningful for the application of the EAF in the medicinal or food industry to prevent and treat oxidative stress and diabetes mellitus.

Palladium-Catalyzed Synthesis, Acetylcholinesterase Inhibition, and Neuroprotective Activities of N-Aryl Galantamine Analogues.

A series of new N-aryl galantamine analogues (5a-5x) were designed and synthesized by modification of galantamine, using Pd-catalyzed Buchwald-Hartwig cross-coupling reaction in good to excellent yields. The cholinesterase inhibitory and neuroprotective activities of N-aryl derivatives of galantamine were evaluated. Among the synthesized compounds, the 4-methoxylpyridine-galantamine derivative (5q) (IC50 = 0.19 μM) exhibited excellent acetylcholinesterase inhibition activity, as well as significant neuroprotective effect against H2O2-induced injury in SH-SY5Y cells. Molecular docking, staining, and Western blotting analyses were performed to demonstrate the mechanism of action of 5q. Derivative 5q would be a promising multifunctional lead compound for the treatment of Alzheimer's disease.

LncRNA Fendrr: involvement in the protective role of nucleolin against H2O2-induced injury in cardiomyocytes

ABSTRACTBackground: Nucleolin is a multifunctional nucleolar protein with RNA-binding properties. Increased nucleolin expression protects cells from H2O2-induced damage, but the mechanism remains unknown. Long noncoding RNAs (lncRNAs) play crucial roles in cardiovascular diseases. However, the biological functions and underlying mechanisms of lncRNAs in myocardial injury remain unclear.Methods: In a nucleolin-overexpressing cardiac cell line, high-throughput technology was used to identify lncRNAs controlled by nucleolin. Cell counting kit-8 assay was used to determine cell viability, lactate dehydrogenase (LDH) assay to detect cell death, caspase activity assay and propidium iodide staining to confirm cell apoptosis, and RNA immunoprecipitation to examine the interaction between Fendrr and nucleolin.Results: We found that Fendrr expression was significantly downregulated in mouse hearts subjected to myocardial ischemia-reperfusion (MI/R) injury. High Fendrr expression abrogated H2O2-mediated injury in cardiomyocytes as evidenced by increased cell viability and decreased cell apoptosis. Conversely, Fendrr knockdown exacerbated the cardiomyocytes injury. Also, nucleolin overexpression inhibits Fendrr downregulation in H2O2-induced cardiomyocyte injury. Fendrr overexpression significantly reversed the role of the suppression of nucleolin expression in H2O2-induced cardiomyocytes.Conclusion: LncRNA Fendrr is involved in the cardioprotective effect of nucleolin against H2O2-induced injury and may be a potential therapeutic target for oxidative stress-induced myocardial injury.

Moschus exerted protective activity against H2O2-induced cell injury in PC12 cells through regulating Nrf-2/ARE signaling pathways

The pivotal characteristics of Alzheimer's disease (AD) are irreversible memory loss and progressive cognitive decline, eventually causing death from brain failure. In the various proposed hypotheses of AD, oxidative stress is also regarded as a symbolic pathophysiologic cascade contributing to brain diseases. Using Chinese herbal medicine may be beneficial for treating and preventing AD. As a rare and valuable animal medicine, Moschus possesses antioxidant and antiapoptotic efficacy and is extensively applied for treating unconsciousness, stroke, coma, and cerebrovascular diseases. We aim to evaluate whether Moschus protects PC12 cells from hydrogen peroxide (H2O2)-induced cellular injury. The chemical constituents of Moschus are analyzed by GC-MS assay. The cell viability, reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP) levels, oxidative stress-related indicators, and apoptotic proteins are determined. Through GC-MS analysis, nineteen active contents were identified. The cell viability loss, lactate dehydrogenase releases, MMP levels, ROS productions, and Malondialdehyde (MDA) activities decreased, and BAX, Caspase-3, and Kelch-like ECH-associated protein 1 expression also significantly down-regulated and heme oxygenase 1, nuclear factor erythroid-2-related factor 2 (Nrf-2), and quinine oxidoreductase 1 expression upregulated after pretreatment of Moschus. The result indicated Moschus has neuroprotective activity in relieving H2O2-induced cellular damage, and the potential mechanism might be associated with regulating the Nrf-2/ARE signaling pathway. A more in-depth and comprehensive understanding of Moschus in the pathogenesis of AD will provide a fundamental basis for in vivo AD animal model research, which may be able to provide further insights and new targets for AD therapy.

METTL3-Mediated N6-Methyladenosine Modification of lncRNA D26496 Suppresses the Proliferation and Migration of Schwann Cells after Sciatic Nerve Injury.

Previous reports showed that LncRNA D26496 was downregulated and N6-methyladenosine (m6A) methyltransferase METTL3 was upregulated in sciatic nerve injury (SNI). YTH-Domain Family Member 2 (YTHDF2) regulated RNA degradation through recognizing m6A sites. However, whether METTL3-mediated m6A of D26496 plays a role in development of SNI is unknown. Therefore, in this study, we established a rat SNI model and a H2O2-induced Schwann cell injury model to investigate the role of D26496 in modulating SNI and how the expression of D26496 was regulated during this process. D26496 expression was downregulated in both models. Rats with SNI displayed severe oxidative stress, manifested as increased MDA production and decreased SOD and GSH activity. Moreover, overexpression of D26496 alleviated H2O2-induced Schwann cell injury likely by promoting cell proliferation and migration and suppressing cell apoptosis and oxidative stress. Mechanism studies found that METTL3 expression was upregulated after SNI, and silencing METTL3 reduced the D26496 m6A level, but upregulated D26496 expression. Subsequent studies found that YTHDF2 was upregulated after SNI, and abundant m6A modified D26496 in the precipitated protein-RNA complexes by anti-YTHDF2 antibody, whereas silencing YTHDF2 promoted D26496 expression but had no effect on m6A levels of D29496. Silencing D26496 reversed the protective effect of knocking down METTL3 or knocking down YTHDF2 on H2O2-induced cell damage. In vivo, D26496 overexpression alleviated SNI-induced neuropathic pain and oxidative stress. In conclusion, our results suggested that D26496 m6A modification mediated by METTL3 and recognition of D26496 m6A sites by YTHDF2 induced D26496 degradation, thereby participating in the progression of SNI.

Protective effect of Sargassum fusiforme polysaccharides on H2O2-induced injury in LO2 cells

IntroductionSargassum fusiform is considered a traditional Chinese medicinal herb to treat many diseases, Sargassum fusiform polysaccharides (SFPS) were found to display many important biological activities. The purpose of this study was to investigate the in vitro antioxidant activity of crude polysaccharide from Sargassum fusiforme and its protective effect against H2O2-induced injury in LO2 cells.MethodsSFPS was extracted from Sargassum fusiforme using water extraction and alcohol precipitation. High-performance liquid chromatography (HPLC) was used to measure its monosaccharide composition. The in vitro antioxidant activity of SFPS was evaluated using scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical assays. Moreover, its hepatoprotective activity was examined by establishing H2O2-induced LO2 cells injury model.Results and discussionThe results showed that the SFPS was composed of Glc, Ara, Fuc, Gal, Man, Rha and Xyl. Meanwhile, SFPS exhibited strong antioxidant activity and potential hepatoprotective effect. Further studies found that SFPS could alleviate LO2 cells injury induced by H2O2 via decreasing malondialdehyde (MDA) and lactate dehydrogenase (LDH) levels, increasing superoxide dismutase (SOD) and catalase (CAT) activities and inhibiting intracellular reactive oxygen species (ROS) production. These results revealed that SFPS had the ability to protect the liver cells from H2O2-induced liver injury through its antioxidant activity.

ADAMTS13 inhibits H2O2-induced human venous endothelial cell injury to attenuate deep-vein thrombosis by blocking the p38/ERK signaling pathway.

Deep vein thrombosis (DVT) is a common complication in hematologic malignancies and immunologic disorders. Endothelial cell injury and dysfunction comprise the critical contributor for the development of DVT. A disintegrin and metalloproteinase with thrombospondin motifs 13 (ADAMTS13), a plasma metalloprotease that cleaves von Willebrand factor, acts as a critical regulator in normal hemostasis. This study was aimed to explore the role of ADAMTS13 in endothelial cell injury during DVT and the possible mechanism. First, human umbilical vein endothelial cells (HUVECs) were exposed to hydrogen peroxide (H2O2). Then, the mRNA and protein expressions of ADAMTS13 were evaluated with the reverse transcription-quantitative polymerase chain reaction and western blot. After treatment with recombinant ADAMTS13 (rADAMTS13; rA13), the viability and apoptosis of H2O2-induced HUVECs were assessed by cell counting kit-8 assay and terminal-deoxynucleoitidyl transferase-mediated nick end labeling staining. In addition, the levels of prostaglandin F1-alpha, endothelin-1, and reactive oxygen species were detected using the enzyme-linked immunosorbent assay and dichloro-dihydro-fluorescein diacetate assay. The expressions of proteins related to p38/extracellular signal-regulated kinase (ERK) signaling pathway were estimated with the western blot. Then, p79350 (p38 agonist) was used to pretreat cells to analyze the regulatory effects of rA13 on p38/ERK signaling in H2O2-induced HUVEC injury. The results revealed that ADAMTS13 expression was significantly downregulated in H2O2-induced HUVECs. The reduced viability and increased apoptosis of HUVECs induced by H2O2 were revived by ADAMTS13. ADAMTS13 also suppressed the oxidative stress in HUVECs after H2O2 treatment. Besides, ADAMTS13 was found to block p38/ERK signaling pathway, and p79350 reversed the impacts of ADAMTS13 on the damage of HUVECs induced by H2O2. To sum up, ADAMTS13 could alleviate H2O2-induced HUVEC injury through the inhibition of p38/ERK signaling pathway.

Inhibition of H2O2-induced apoptosis of GC2-spg cells by functionalized selenium nanoparticles with lentinan through ROS-mediated ERK/p53 signaling pathways

A H2O2-induced oxidative stress injury cell model was established to investigate the antioxidant effect of nano-selenium on mouse spermatocyte lines and the regulation mechanism of the expression level and activity of selenium-containing antioxidant enzymes induced by oxidative stress. A safe and effective nano-drug system of functionalized selenium-containing nanoparticles (SeNPs) was developed with lentinan (LNT) (SeNPs@LNT). Mice spermatocyte line GC2-spg cells were treated with SeNPs@LNT (1, 2, 4, 8, 16, 32 μM) for 24–72 h to evaluate the cytotoxicity of selenium. GC2-spg cells were randomly divided into the following groups: control, hydrogen peroxide (H2O2), SeNPs@LNT, and H2O2+SeNPs@LNT groups. H2O2+SeNPs@LNT group was pretreated with SeNPs@LNT 4 μM for 12 h, followed by H2O2 600 μM for 8 h. The cell viability decreased in the H2O2 group and increased significantly in the SeNPs@LNT group. Compared with the H2O2 group, the SeNPs@LNT+H2O2 group exhibited obvious red fluorescence, indicating a higher level of mitochondrial membrane potential. The content of intracellular reactive oxygen species (ROS) in the SeNPs@LNT group reduced significantly, and the intensity of green fluorescence in the SeNPs@LNT+H2O2 group decreased significantly compared with the H2O2 group, indicating the inhibitory effect of SeNPs@LNT on the generation of ROS-induced oxidative stress. The activity of GPx and SOD increased significantly in the SeNPs@LNT group. The expression of p53 decreased significantly under the intervention of nano-selenium, and GPx1 expression increased. In the oxidative stress group, the expressions of DNA damage-related proteins and apoptosis-related proteins were higher than those in other groups. Thus, SeNPs@LNT can promote GC2-spg cell proliferation, improve GPx and SOD activities, remove intracellular ROS, and reduce mitochondrial damage and functional abnormalities caused by oxidative stress by regulating the ERK and p53 protein levels. SeNPs@LNT has good biological activity and antioxidant effect, which can be used to protect the male reproductive system from oxidative stress.

Protective Effect of Phloretin against Hydrogen Peroxide-Induced Oxidative Damage by Enhancing Autophagic Flux in DF-1 Cells.

Phloretin (PHL) is a dihydrochalcone flavonoid isolated from the peel and root bark of apples, strawberries, and other plants with antioxidative characteristic. In this study, we aimed to investigate the protective effect and the potential mechanism of PHL on hydrogen peroxide (H2O2)-induced oxidative damage in DF-1 cells. The results showed that PHL exhibited no cytotoxic effect on DF-1 cells at concentration below 20 μM. PHL markedly increased H2O2-reduced cell viability, decreased H2O2-induced apoptosis, as evidenced by reduced apoptosis rate, the upregulation of gene and protein level of Bcl-2, and the downregulation of gene and protein level of Bax and Cleaved caspase3. In addition, PHL reduced H2O2-induced reactive oxygen species (ROS) production and restored antioxidant enzymes activities as well as mitochondrial membrane potential in a dose-dependent manner. Moreover, PHL prior to H2O2 further increased LC3-II level, promoted p62 turnover and improved lysosomal function. Importantly, autophagy inhibitor chloroquine (CQ) reversed the protective effect of PHL, and increased H2O2-induced apoptosis. Furthermore, PHL inhibited the phosphorylation levels of ERK, p38, and JNK. Collectively, these results indicate that PHL could attenuate H2O2-induced oxidative injury and apoptosis by maintaining lysosomal function and promoting autophagic flux, and MAPKs pathway may be involved in this process. Our study provides evidence that PHL could as a new strategy to against oxidative damage in poultry industry.

Three novel antioxidant peptides isolated from C-phycocyanin against H2O2-induced oxidative stress in zebrafish via Nrf2 signaling pathway

BackgroundC-phycocyanin (C-PC), a phycobiliprotein from Spirulina platensis, has been confirmed to be an effective antioxidant. Duing to the large molecular weight protein, C-PC is hardly absorbed in the human gut and easy coagulates into lumps. In light of this, highly pure, easy absorption, and small molecular weight polypeptides has won the attention in the recent past. However, there are few studies on the C-PC bioactive peptides. Thus, the objective of this study was find natural multifunctional antioxidant peptides from C-PC and demonstrate their mechanisms.MethodIn this study, novel antioxidant peptides from pancreatin hydrolysate of C-PC were isolated and purified by using a multi-bioassay-guided method. The DPPH and ABTS radical scavenging in vitro and antioxidant zebrafish model in vivo were used to evaluate the antioxidant activities. Furthermore, the underlying molecular mechanisms of these peptides were investigated by measuring the level of ROS, MDA, SOD, CAT and gene expression in Nrf2 signaling pathway.ResultsTotal three novel active peptides, MHLWAAK (Met-His-Leu-Trp-Ala-Ala-Lys), MAQAAEYYR (Met-Ala-Gln-Ala-Ala-Glu-Tyr-Tyr-Arg), and MDYYFEER (Met-ASP-Tyr-Tyr-Phe-Glu-Glu-Arg) were isolated and purified from pancreatin hydrolysate of C-PC. These synthesized peptides displayed high DPPH and ABTS radical scavenging ability. In addition, in a zebrafish model, the three peptides significantly protected zebrafish embryos from H2O2-induced oxidative injury without toxicity by inhibiting ROS generation, preventing MDA formation, and upregulating the activities of SOD and CAT. Further experiments showed that these peptides could significantly regulated oxidative stress via activating the Nrf2 signaling pathway.ConclusionThis study indicates that the antioxidant peptides from C-PC could serve as powerful antioxidants for preventing and treating various diseases associated with oxidative stress.

Quassinoids from Picrasma chinensis with Insecticidal Activity against Adults and Larvae of Diaphorina citri Kuwayama and Neuroprotective Effect.

Eleven new tetracyclic quassinoids, picrachinensin A-K (1-11), along with six known congeners, were isolated from the stems and leaves of Picrasma chinensis. Their structures were elucidated by integrated multiple spectroscopic techniques, single-crystal X-ray diffraction analysis, and electronic circular dichroism. Notably, compounds 3 and 4 are a pair of undescribed epimers, and 8 and 9 are unusual quassinoids with a hydroxymethyl group at C-13. Biologically, compound 7 exhibited insecticidal activity on both adults and larvae of Diaphorina citri Kuwayama even more effectively than the positive control (abamectin), with an LD50 of 55.69 mg/L for adults and a corrected mortality rate of 30.42 ± 2.78% for larvae (100 mg/L). According to preliminary structure-activity relationship investigations, the hydroxymethyl at the C-13 position of quassinoids was beneficial for their insecticidal activity. In addition, compounds 1, 4, and 12 exhibited excellent neuroprotective effect against H2O2-induced oxidative injury on SH-SY5Y cells, with more potent activity than the positive control (Trolox), and all the compounds exhibited no cytotoxicity to SH-SY5Y and BV-2 cells at the indicated concentrations.

Extraction and Purification of Flavonoids from Buddleja officinalis Maxim and Their Attenuation of H2O2-Induced Cell Injury by Modulating Oxidative Stress and Autophagy.

Cataracts are an ailment representing the leading cause of blindness in the world. The pathogenesis of cataracts is not clear, and there is no effective treatment. An increasing amount of evidence shows that oxidative stress and autophagy in lens epithelial cells play a key role in the occurrence and development of cataracts. Buddleja officinalis Maxim flavonoids (BMF) are natural antioxidants and regulators that present anti-inflammatory and anti-tumor effects, among others. In this study, we optimized the extraction method of BMFs and detected three of their main active monomers (luteolin, apigenin, and acacetin). In addition, a model of oxidative damage model using rabbit lens epithelial cells induced by hydrogen peroxide (H2O2). By detecting the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), and OH (OH), the expression of autophagosomes and autolysosomes were observed after MRFP-GFP-LC3 adenovirus was introduced into the cells. Western blotting was used to detect the expression of Beclin-1 and P62. Our research results showed that the optimal extraction parameters to obtain the highest yield of total flavonoids were a liquid−solid ratio of 1:31 g/mL, an ethanol volume fraction of 67%, an extraction time of 2.6 h, and an extraction temperature of 58 °C. Moreover, the content of luteolin was 690.85 ppb, that of apigenin was 114.91 ppb, and the content of acacetin was 5.617 ppb. After oxidative damage was induced by H2O2, the cell survival rate decreased significantly. BMFs could increase the levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decrease the levels of malondialdehyde (MDA) and OH (OH). After the MRFP-GFP-LC3 virus was introduced into rabbit lens epithelial cells and detecting the expression of P62 and Beclin-1, we found that the intervention of BMF could promote the binding of autophagosomes to lysosomes. Compared with the model group, the level of P62 in the low-, middle-, and high-dose groups of BMF was significantly down-regulated, the level of Beclin-1 was significantly increased, and the difference was statistically significant (p < 0.05). In other words, the optimized extraction method was better than others, and the purified BMF contained three main active monomers (luteolin, apigenin, and acacetin). In addition, BMFs could ameliorate the H2O2-induced oxidative damage to rabbit lens cells by promoting autophagy and regulating the level of antioxidation.

PI3K/AKT/mTOR, NF-κB and ERS pathway participated in the attenuation of H2O2-induced IPEC-J2 cell injury by koumine

Ethnopharmacological relevanceKoumine, an indole alkaloid extracted from Gelsemium elegans Benth, exerts anti-inflammation and antioxidant activities. However, the effects of koumine on intestinal injury induced by H2O2 and its potential molecular mechanisms need larger studies.Aim of the study: We established an IPEC-J2 cell damage model induced by H2O2 to explore the protective mechanism of koumine on intestinal injury. Materials and methodsIn the experiment, cell damage models were made with hydrogen peroxide. To assess the protective effect of koumine on H2O2-induced IPEC-J2 cell injury, CCK-8, the release of LDH and ROS, transmission electron microscopy and Annexin V-FITC/PI were employed. Western Blot and Quantitative Real-time PCR were used to determine the potential alleviated mechanism of koumine on H2O2-trigged IPEC-J2 cell damage. ResultsThe results of CCK-8 and LDH implied that koumine has a mitigative effect on H2O2-induced cell damage via upregulating cell viability and suppressing cell membrane fragmentation. Simultaneously, koumine notably inhibited the level of pro-inflammatory factors (IL-1β, IL-6, IL-8, TNF-α and TGF-β), the over-production of ROS along with decreasing the injury of mitochondrion, endoplasmic reticulum and lysosome induced by H2O2. Moreover, koumine dramatically attenuated H2O2-triggered IPEC-J2 cell apoptosis and autophagy. Subsequently, Western blot analysis identified NF-ΚB, PI3K and ERS as possible pathway responsible for the protective effect of koumine on H2O2-stimulated IPEC-J2 cell inflammation. ConclusionsThis in vitro experimental study suggests that koumine suppresses the H2O2-induced activation of inflammatory pathways, oxidative injury, ER stress, apoptosis and autophagy, which provide a rationale for therapeutically use in major intestinal diseases.

GATA3 ameliorates melanocyte injuries in vitiligo through SIRT3-mediated HMGB1 deacetylation.

Vitiligo is a skin depigmentation disorder. GATA3 expression is downregulated in vitiligo patients, and its role and regulatory mechanism in vitiligo are unclear. GATA3 and HMGB1 levels were detected by qRT-PCR in peripheral blood cells of vitiligo patients and healthy controls, as well as H2 O2 -treated PIG1 cells. Their expression correlation was assessed by Pearson analysis. qRT-PCR, MTT assay, Ki67 immunostaining, flow cytometry, ELISA and Western blot were applied to determine GATA3 expression, cell survival, cell proliferation, cell apoptosis, melanin contents, and melanin-related protein expressions. The cellular distributions of HMGB1 and its deacetylation levels were detected by Western blot. The binding of GATA3 to SIRT3 promoter and effects on SIRT3 expression and HMGB1 deacetylation was determined by dual-luciferase assay, ChIP assay, and Western blot. GATA3 was decreased, and HMGB1 was increased in vitiligo. Pearson correlation assay showed that they were negatively correlated. H2 O2 significantly inhibited cell survival, proliferation, melanin secretion, and melanin-related protein expressions but remarkably increased cell apoptosis. GATA3 overexpression could distinctly reverse the effects of H2 O2 through decreasing HMGB1 expression and retained HMGB1 in nuclear due to the decreased HMGB1 acetylation. GATA3 bound to the SIRT3 and subsequently decreased H2 O2 -induced HMGB1 acetylation. Overexpressing HMGB1 or knockdown of SIRT3 could reverse the effects of GATA3 overexpression. GATA3 inhibited H2 O2 -induced injury in PIG1 cells and enhanced melanin secretion by SIRT3-regulated HMGB1 deacetylation, which might provide new evidence to treat vitiligo.