Oxidative Stress-induced Cell Research Articles

Study on inhibitory effects of AsA, ZnCl2, and BAPTA-AM on Cd2+-induced cell oxidative stress and cytotoxicity by scanning electrochemical microscopy (SECM) technology

Cadmium (Cd) can cause cell oxidative stress and cytotoxicity.

Antioxidant Iron Oxide Nanoparticles: Their Biocompatibility and Bioactive Properties

A lot of nanomaterials have been applied to various nano-biotechnological fields, such as contrast agents, drug or gene delivery systems, cosmetics, and so on. Despite the expanding usage of nanomaterials, concerns persist regarding their potential toxicity. To address this issue, many scientists have tried to develop biocompatible nanomaterials containing phytochemicals as a promising solution. In this study, we synthesized biocompatible nanomaterials by using gallic acid (GA), which is a phytochemical, and coating it onto the surface of iron oxide nanoparticles (IONPs). Importantly, the GA-modified iron oxide nanoparticles (GA-IONPs) were successfully prepared through environmentally friendly methods, avoiding the use of harmful reagents and extreme conditions. The presence of GA on the surface of IONPs improved their stability and bioactive properties. In addition, cell viability assays proved that GA-IONPs possessed excellent biocompatibility in human dermal papilla cells (HDPCs). Additionally, GA-IONPs showed antioxidant activity, which reduced intracellular reactive oxygen species (ROS) levels in an oxidative stress model induced by hydrogen peroxide (H2O2). To investigate the impact of GA-IONPs on exosome secretions from oxidative stress-induced cells, we analyzed the number and characteristics of exosomes in the culture media of HDPCs after H2O2 stimulation or GA-IONP treatment. Our analysis revealed that both the number and proportions of tetraspanins (CD9, CD81, and CD63) in exosomes were similar in the control group and the GA-IONP-treated groups. In contrast, exosome secretion was increased, and the proportion of tetraspanin was changed in the H2O2-treated group compared to the control group. It demonstrated that treatment with GA-IONPs effectively attenuated exosome secretion induced by H2O2-induced oxidative stress. Therefore, this GA-IONP exhibited outstanding promise for applications in the field of nanobiotechnology.

Cordyceps militaris Carotenoids Protect Human Retinal Endothelial Cells against the Oxidative Injury and Apoptosis Resulting from H2O2.

Vision loss is primarily caused by age-related macular degeneration (AMD) due to oxidative retinal pigment epithelial (RPE) cell injury. Carotenoid utilization is deemed a possible strategy for treating AMD. Cordyceps militaris has advantages like immunomodulatory, anti-inflammatory, and antioxidative characteristics. This paper assessed the possible protective influence of carotenoids obtained by isolating and purifying the Cordyceps militaris (CMCT) into human RPE cells (ARPE-19) damaged by hydrogen peroxide (H2O2). The findings demonstrated that CMCT safeguarded the ARPE-19 cells against the damage and apoptosis caused by H2O2 and oxidative stress via Bcl-2 protein upregulation, as well as the expression of Bax and cleaved caspase-3 protein. In addition, CMCT treatment increased cell survival and restricted the generation of H2O2-induced reactive oxygen species (ROS) and the protein expression of NADPH oxidase-1 (NOX1). Additionally, the CMCT treatment of H2O2-induced ARPE-19 cells ameliorated high malondialdehyde (MDA) levels in oxidative stress-induced cells. The catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH) returned to standard levels, which were governed by the higher expression of nuclear Nrf2 protein in the ARPE-19 cells. Moreover, this study showed that CMCT safeguarded the ARPE-19 cells against the damage caused by oxidative stress via its antioxidant activity and antiapoptotic functionality, suggesting the potential therapeutic role of CMCT in AMD prevention and mitigation.

Preparation and Characterization of pH-Sensitive Capsosomes for Oral Delivery of Therapeutic Proteins.

Oral administration of therapeutic proteins is very challenging because of gastrointestinal instability and decomposition. In this study, we developed a system for oral delivery of superoxide dismutase (SOD) as one of the therapeutic proteins. SOD-loaded capsosomes (SOD-C) were formed by the assembly of chitosan-coated solid lipid nanoparticles and SOD-loaded liposomes (SOD-L). Unlike raw SOD activity decreases to 19.41% in SGF and 13.70% in SIF, the SOD-C in SGF (89.30%) condition retained its initial catalytic activity and decreased but exhibited a three-fold higher raw SOD activity even after incubation in SIF (41.63%). TEM analysis indicated that after intestinal digestion, the residual amount of intact liposomes affected the higher catalytic activity of SOD-C compared to raw SOD and SOD-L. Based on these results, significantly higher cellular uptake of SOD-C was observed compared to raw SOD. Also, SOD-C remarkably suppressed the cellular malondialdehyde (MDA) concentration by maintaining the antioxidative capacity of SOD to remove MDA produced in the oxidative stress-induced cells, thereby contributing to a significant five-fold difference with SOD-R (p < 0.05). This delivery system can facilitate the oral application of other therapeutic proteins, improving gastrointestinal stability.

Overexpression of V-ATPase B2 attenuates lung injury/fibrosis by stabilizing lysosomal membrane permeabilization and increasing collagen degradation

Excessive oxidative stress causes lysosomal membrane permeabilization (LMP), which leads to cell death. Vacuolar ATPase (V-ATPase) is the enzyme responsible for pumping H+ into the cytosol and thus maintaining intracellular pH. Previously, we reported that V-ATPase B2 subunit expression is upregulated in the TiO2-exposed lung epithelium. We investigated the role of the lysosomal V-ATPase B2 subunit in oxidative stress-induced alveolar epithelial cell death and in an experimental lung injury/fibrosis model. Overexpression of V-ATPase B2 increased lysosomal pH and lysosomal activities in the cells. In the presence of H2O2, overexpression of V-ATPase B2 increased survival, and silencing of V-ATPase B2 dramatically increased cell death. Overexpression of V-ATPase B2 diminished H2O2-triggered LMP, as evidenced by a reduction in acridine orange staining and leakage of cathepsin D from the lysosome to the cytoplasm. In addition, V-ATPase B2-overexpressing macrophages exhibited significantly enhanced uptake and degradation of collagen. V-ATPase B2-overexpressing transgenic mice showed significant inhibition of the bleomycin-induced increases in lung inflammation and fibrosis. We conclude that V-ATPase B2 is critical for maintaining lysosomal activities against excessive oxidative stress by stabilizing LMP. Our findings reveal a previously unknown role of this V-ATPase subunit in a lung injury and fibrosis model.

Dasatinib plus quercetin attenuates some frailty characteristics in SAMP10 mice

Senolytics are a class of drugs that selectively remove senescent cells. Dasatinib and quercetin have been discovered, and their combination has shown various anti-ageing effects. The SAMP10 mouse strain is a model of brain ageing. Here, we investigated the effect of combination on frailty characteristics in SAMP10. By comparing SAMP10 with SAMR1 mice as normal ageing controls, we investigated some frailty characteristics. Frailty was assessed at 18–38 weeks of age with a clinical frailty index. Motor and cognitive function of these mice were evaluated using behavioral experiments. SAMP10 mice were divided into vehicle and combination, and these functions and histological changes in the brain hippocampus were investigated. Finally, the in vitro effects of combination on oxidative stress-induced senescent muscle and neuronal cells were investigated. As a result, we found that frailty index was higher in SAMP10 than SAMR1. Motor and cognitive function were worse in SAMP10 than SAMR1. Furthermore, combination therapy improved frailty, motor and cognitive function, and the senescent phenotype of the hippocampus compared with vehicle in SAMP10. In summary, SAMP10 showed more marked frailty characteristics than SAMR1, and dasatinib and quercetin attenuated them in SAMP10. From our results, senolytic therapy might contribute protective effects against frailty.

Evaluation of the effect of nitrate and chloride on Cd(II)-induced cell oxidative stress by scanning electrochemical microscopy.

Cadmium (Cd) is one of the most prevalent toxic metal pollutants, which is widely distributed in various environmental media and organisms. Literature studies have documented that Cd could stimulate cellular oxidative stress, and the increased intracellular reactive oxygen species (ROS) might destroy certain proteins and DNA and subsequently lead to cell apoptosis. Although several studies have studied the co-exposure between cadmium and other metals, information on the potential effects of Cd and its counterions is still lacking. In the present study, we explored the effects of nitrate and chloride on oxidative stress induced by Cd(II) at environmental exposure levels in human breast cancer cells (MCF-7) using scanning electrochemical microscopy (SECM). After incubation in CdCl2 or Cd(NO3)2, ROS production is concentration-dependent and time-dependent, and the variation trend is consistent. When MCF-7 cells were incubated at a constant Cd2+ concentration, it was found that the higher the concentration ratio of Cd(NO3)2/CdCl2, the less ROS was generated. Combined with cell-viability, intracellular acidification as well as antioxidants system tests, we observed that nitrate could be reduced to nitrite and then inhibit Cd-induced oxidative stress. Benefitting from real-time in situ imaging of cells by SECM, H2O2 was detected and quantified in a noninvasive way, and the effect of Cd at environmental exposure levels on cellular oxidative stress was explored deeper and more comprehensively. Prospectively, cytotoxicological methods based on the SECM technique would be established to explore toxic pollutant co-exposure issues at environmental exposure levels.

Effect of hop mixture containing xanthohumol on sleep enhancement in a mouse model and ROS scavenging effect in oxidative stress-induced HT22 cells

Effect of hop mixture containing xanthohumol on sleep enhancement in a mouse model and ROS scavenging effect in oxidative stress-induced HT22 cells

Low Concentration Ethanol Prevents Oxidative Stress- Induced Cardiac Cells Injury Under HyperglycemicConditions by Inhibiting the SAPK/JNK Signaling Pathway and ROS Generation

The purpose of this study was to determine the effects and mechanisms of ethanol on oxidative stress-induced cardiac H9c2 cells mitochondrial injury under hyperglycemic conditions. Under hyperglycemic conditions, ethanol pretreatment (10-100 μM) prevented H2O2-induced mitochondria swelling, as well as decreased cell viability and Respiratory Control Ratio (RCR) in the H9c2 cells. It also prevented TMRE fluorescence intensity loss and DCF fluorescence intensity increase under hyperglycemic conditions. These effects of ethanol were reversed by the SAPK/JNK agonist, anisomycin. Finally, treatment of H9c2 cells with 33mM glucose significantly enhanced Akt and ERK phosphorylation, which was not affected by ethanol. However, ethanol decreased the phosphorylation of SAPK/JNK under hyperglycemic conditions. Collectively, these findings indicate that under hyperglycemic conditions, that ethanol prevents oxidative stress-induced mitochondrial injury in cardiac H9c2 cells by preventing ROS generation via inhibiting the SAPK/JNK signaling pathway.

205-OR: Docosahexaenoic Acid Suppresses Oxidative Stress-Induced Autophagy and Cell Death through the AMPK-Dependent Signaling Pathway in Immortalized Adult Rat Schwann (IFRS1) Cells

Autophagy is a catabolic process that removes damaged intracellular organelles components by lysosomal degradation, but it is also activated by oxidative stress. We previously reported that the docosahexaenoic acid (DHA) suppressed oxidative stress-induced autophagy and cell death in immortalized adult rat Schwann (IFRS1) cells. However, the detailed mechanism has not been clarified yet. Therefore, we aimed to elucidate the intracellular signal transduction pathway by which DHA suppresses oxidative stress-induced autophagy in IFRS1 cells. Treatment with tert-butyl hydroperoxide (tBHP) for 3 hours decreased cell viability measured by MTT assay in IFRS1 cells, while pretreatment with 10 μM DHA for 12 hours significantly protected tBHP-induced cytotoxicity. The signal transduction of autophagy was assessed by immunoblotting of LC3, p62, AMP-activated protein kinase (AMPK) phosphorylation and UNC51-like kinase (ULK1) phosphorylation in IFRS1 cells. 50 μM tBHP increased the LC3-II/LC3-I ratio, and AMPK phosphorylation, whereas tBHP decreased the p62 protein expression, indicating that autophagy was induced by tBHP. Pretreatment with 10 μM DHA for 12 hours significantly decreased the LC3-II/LC3-I ratio and AMPK phosphorylation that were increased by tBHP, whereas DHA increased the p62 protein expression that was decreased by tBHP. p70S6Kinase and 4E-BP phosphorylation was not changed either by tBHP or by DHA. Autophagosome and autolysosome were induced by 50 μM tBHP in IFRS1 cells, as demonstrated by DAPRed and DALGreen staining. DHA pretreatment significantly reduced the production of tBHP-induced autophagosome, but suppression of autolysosome was partial. These results suggest that DHA may prevent against diabetic neuropathy by attenuating oxidative stress-induced autophagy and cell death through the AMPK-dependent signaling pathway in Schwann cells. Disclosure Y. Tatsumi: Research Support; Self; Daiichi Sankyo, Johnson &amp; Johnson, Kyowa Kirin Co., Ltd., Lilly Diabetes, MSD K. K., Novo Nordisk Pharma Ltd., Ono Pharmaceutical Co., Ltd., Sanofi K. K., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co. J. Nakamura: Research Support; Self; Astellas Pharma Inc., Daiichi Sankyo Company, Limited, Eli Lilly Japan K. K., Japan Tobacco Inc., Novartis Pharma K. K., Novo Nordisk Pharma Ltd., Ono Pharmaceutical Co., Ltd., Sanofi K. K., Sumitomo Dainippon Pharma Co., Ltd., Taisho Pharmaceutical Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co., Speaker’s Bureau; Self; Astellas Pharma Inc., AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo Company, Limited, Eli Lilly Japan K. K., Kowa Company, Ltd., Mitsubishi Tanabe Pharma Corporation, MSD K. K., Novartis Pharma K. K., Novo Nordisk Pharma Ltd., Ono Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited. K. Sango: None. K. Kato: None. A. Kato: None. N. Niimi: None. H. Yako: None. T. Himeno: None. M. Kondo: None. S. Tsunekawa: None. Y. Kato: None. H. Kamiya: Speaker’s Bureau; Self; Eli Lilly Japan K. K., MDS Co., Ltd., Novartis Pharma K. K., Novo Nordisk Pharma Ltd., Ono Pharmaceutical Co., Ltd., Sanofi K. K., Sumitomo Dainippon Pharma Co., Ltd. Funding Grant-in-Aid for Scientific Research (18K06763)

Protein Hydrolysate of Silkworm Pupa Prevents Memory Impairment Induced by Oxidative Stress in Scopolamine-Induced Mice via Modulating the Cholinergic Nervous System and Antioxidant Defense System.

Silkworm pupae (Bombyx mori) is an edible insect that has been reported to contain high-quality proteins, lipids, minerals, and vitamins, and to possess high antioxidant activity. However, there have been no studies on the neuroprotective effects of silkworm pupae. Therefore, we investigated a water extract of silkworm pupae with protease (WSP) as a functional and therapeutic candidate for neurodegenerative disorders. First, we evaluated the effect of WSP on oxidative stress-induced mouse hippocampal neuronal cells (HT-22 cells). Cell viability diminished by addition of glutamate but was significantly recovered by WSP treatment. Furthermore, WSP significantly decreased the release of lactate dehydrogenase and generation of intracellular reactive oxygen species in oxidative stress-induced cells. In addition, in scopolamine-treated mice, WSP attenuated memory impairment, as demonstrated in the Morris water maze and passive avoidance tests, indicating protection of neuronal cells against oxidative damage. Moreover, WSP prevented scopolamine-induced increases in acetylcholinesterase activity and decreases in choline-acetyltransferase activity. Finally, treatment with WSP enhanced the antioxidant defense system by regulating the activities of antioxidant enzymes. Overall, this study showed that WSP exerted antioxidant and memory enhancing action against oxidative stress.

Overexpression of MicroRNA-122 Resists Oxidative Stress-Induced Human Umbilical Vascular Endothelial Cell Injury by Inhibition of p53.

Deep venous thrombosis (DVT) constitutes a great threat to health worldwide. Endothelial cell injury and dysfunction comprise the critical contributor for the development of DVT. However, the mechanism behind it remains poorly elucidated. The study is aimed at investigating the role of microRNA-122 (miR-122) and oxidative stress on DVT. The results showed that miR-122 overexpression dampened H2O2-evoked cytotoxic injury in human umbilical vein endothelial cells (HUVECs) by increasing cell viability, suppressing cell apoptosis and oxidative stress injury. Notably, miR-122 overexpression attenuated provasoconstriction factor endothelin-1 (ET-1) expression in HUVECs exposed to H2O2 but enhanced the productions of vasodilatation factor Prostaglandin F1α (PGF1α). Moreover, inhibition of miR-122 had the opposite results. miR-122 could inhibit the expression of p53. Low expression of p53 could enhance the protection of miR-122 on HUVEC injury. This study highlights that miR-122 overexpression may restore H2O2-induced HUVEC injury by regulating the expression of p53.

Cosmeceutical potentials of Curcuma mangga Val. extract in human BJ fibroblasts against MMP1, MMP3, and MMP13

Oxidative stress, the disrupted oxidation-reduction mechanism in our body, is caused by the excessive exposure of free radicals and the impaired antioxidant defenses that can accelerate skin aging. Antioxidants can be obtained from nature, which are available widely in therapeutic-rich plants, such as white saffron (Curcuma mangga Val., denoted as C. mangga). Although many pieces of evidence reveal that C. mangga contains an abundance of phenolic compounds and has antioxidative effects, its cosmeceutical potentials remain unclear. The present study aimed to disclose the unexplored antiaging potentials of C. mangga extract (CME) in oxidative stress-induced human BJ fibroblasts with a focus on collagen protection against pro-inflammatory mediators MMP1, MMP3, and MMP13. The oxidative stress-induced cells were treated with CME and curcumin at different doses. The results showed that treatment using CME (25 μg/mL) could maintain the collagen contents up to 18.45 ± 0.68 μg/mL in H2O2-treated fibroblasts (only ~26.63% reduction in collagen contents), while the figure for the negative control was the lowest (12.79 μg/mL), showing a significant reduction in collagen contents by 49.13%. In addition, the gene expression of pro-inflammatory MMPs arose significantly in BJ fibroblasts after oxidative stress induction using 200 μM H2O2, in which the expression for MMP1, MMP3, and MMP13 increased by 7.10, 38.96, and 2.69 times, respectively. Interestingly, CME treatment (100 μg/mL) could effectively inhibit MMP1, MMP3, and MMP13 gene expression by 3.65, 34.62, and 2.02 times, respectively. In conclusion, CME showed favorable antiaging activities in H2O2-treated human BJ fibroblasts as confirmed by the low levels of gene expression of MPP1, MMP3, and MMP13 after treatment with CME.

MSC-derived exosomes protect against oxidative stress-induced skin injury via adaptive regulation of the NRF2 defense system

Oxidative stress is a major cause of skin injury induced by damaging stimuli such as UV radiation. Currently, owing to their immunomodulatory properties, mesenchymal stem cell-derived exosomes (MSC-Exo), as a nanotherapeutic agent, have attracted considerable attention. Here, we investigated the therapeutic effects of MSC-Exo on oxidative injury in H2O2-stimulated epidermal keratinocytes and UV-irradiated wild type and nuclear factor-erythroid 2-related factor-2 (Nrf2) knocked down cell and animal models. Our findings showed that MSC-Exo treatment reduced reactive oxygen species generation, DNA damage, aberrant calcium signaling, and mitochondrial changes in H2O2-stimulated keratinocytes or UV-irradiated mice skin. Exosome therapy also improved antioxidant capacities shown by increased ferric ion reducing antioxidant power and glutathione peroxidase or superoxide dismutase activities in oxidative stress-induced cell and skin injury. In addition, it alleviated cellular and histological responses to inflammation and oxidation in cell or animal models. Furthermore, the NRF2 signaling pathway was involved in the antioxidation activity of MSC-Exo, while Nrf2 knockdown attenuated the antioxidant capacities of MSC-Exo in vitro and in vivo, suggesting that these effects are partially mediated by the NRF2 signaling pathway. These results indicate that MSC-Exo can repair oxidative stress-induced skin injury via adaptive regulation of the NRF2 defense system. Thus, MSC-Exo may be used as a potential dermatological nanotherapeutic agent for treating oxidative stress-induced skin diseases or disorders.

Effects of tannase-converted green tea extract on skeletal muscle development

BackgroundThe aim of this study was to investigate the effect of tannase-converted green tea extract with a high (−)-epicatechin (EC), (−)-epigallocatechin (EGC), and gallic acid (GA) content on myotube density and fusion in normal and oxidative stress-induced C2C12 skeletal muscle cells. Although the use of green tea extract is considered beneficial, cellular and molecular mechanisms of action of tannase-converted green tea extracts that are used as potential muscle growth materials have not been thoroughly studied.MethodsThis study used histological analysis and molecular biology techniques, and compared the results with those for AMPK activator 5-aminoimidazole-4-carboxamide-1-β-D-ribonucleoside (AICAR) and green tea extracts.ResultsThe myotube density of normal and oxidative stress-induced C2C12 cells was significantly higher in the tannase-converted green tea extract-treated group than that observed in the other groups (normal cells: P < 0.01; oxidative stress-induced cells: P < 0.05). In addition, tannase-converted green tea extract and green tea extract treatments significantly upregulated the genetic expression of myogenin, Myf5, and MyoD (P < 0.05). The levels of AMP-activated protein kinase-α (AMPKα) and muscle RING-finger protein-1 (MuRF-1) in the tannase-converted green tea extract group were higher than those in the AICAR and green tea extract groups (P < 0.05).ConclusionsTaken together, our findings describe that the high levels of EC, EGC, and GA in the tannase-converted green tea extract are attributable to the morphological changes in C2C12 cells and intercellular signaling pathways. Therefore, tannase-converted green tea extract can be used in the treatment of sarcopenia.

The modified G6PD deficiency screening test

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, which involves the mutation of the G6PD gene on the X chromosome, is the most common enzyme defect in humans. G6PD produces nicotinamide adenine dinucleotide phosphate (NADPH) for red blood cell protection from oxidative stress. Oxidative stress-induced red blood cell hemolysis in G6PD-deficient patients leads to anemia, jaundice, acute renal failure, and kernicterus in newborns. Currently, the fluorescent spot test (FST) is widely used for G6PD deficiency screening. This test detects NADPH production under UV light. This study purposed to modify the G6PD deficiency screening test based on NADPH production and the ability to detect the results of the color change in the color of the reaction. Blood samples of 60 subjects were collected and screened for G6PD deficiency using FST method. All samples were tested with the modified G6PD screening test and the quantitative assay kit. The results from the modified test showed the color red for normal cases, whereas the color brown indicated G6PD deficiency cases. The cutoff value of G6PD activity detected by the quantitative method was less than 2.9 U/gHb for G6PD deficiency. The precision of this study was 100 %. The results of sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of the modified test were 100 %, 96.7 %, 100 %, and 96.7 %, respectively. The modified G6PD screening test can be used for the screening of G6PD deficiency in newborns, for support through providing more information, and for self-protection from oxidative stress.

Albumin evokes Ca2+-induced cell oxidative stress and apoptosis through TRPM2 channel in renal collecting duct cells reduced by curcumin

In proteinuric nephropathies of chronic kidney disease, the epithelial cells of the nephron including the collecting duct are exposed to high concentrations of luminal albumin. Albumin is taken up from collecting duct cells by endocytosis causing excessive reactive oxygen species (ROS) production and a proinflammatory response. Curcumin used in the traditional medicine possesses anti-inflammatory and antioxidant effects. ROS and ADP-ribose (ADPR) activate the cation channel TRPM2. We hypothesize, that albumin-induced cell stress and proinflammatory response are mediated by Ca2+ and can be reduced by curcumin. The cortical collecting duct (CCD) cells mpkCCDc14 exhibit spontaneous and inducible Ca2+ oscillations, which can be blocked by pre-treatment with curcumin. Curcumin accumulates in plasma membrane and intracellular vesicles, where it interferes with TRPM2 and decreases the influx of Ca2+. Albumin reduces cell viability and increases apoptosis, NF-κB activation, and mitochondrial membrane depolarization via Ca2+-dependent signaling, which results in increased ROS production. Albumin-induced cell stress is diminished by the inhibition of TRPM2 after administration of curcumin and ADPR (PARP1) inhibitors. Curcumin did not reduce the Ca2+ elevation induced by thapsigargin in Ca2+-free medium, but it reduced the function of store-operated Ca2+ channels and ATP-evoked Ca2+ response. In conclusion, albumin-induced oxidative stress is mediated by Ca2+-dependent signaling via TRPM2 and leads to cell damage and a proinflammatory response, strengthening the role of CCD cells in the progression of chronic kidney disease.

GKN2 promotes oxidative stress-induced gastric cancer cell apoptosis via the Hsc70 pathway

BackgroundThe GKN2 is a secretory protein, whose levels decrease in gastric cancer. The present study aimed to investigate the expression, function and mechanism of action of GKN2 in gastric cancer.MethodsMolecular biology assays were performed to elucidate the function and underlying mechanisms of GKN2 in gastric cancer under stress-induced condition in vivo and in vitro. Clinical specimens were used to assess the correlation of GKN2 and prognosis.ResultsWe found that overexpression of GKN2 significantly enhanced apoptosis and growth arrest in vitro. GKN2 expression increased in gastric cancer cells exposed to hydrogen peroxide and promoted reactive oxygen species-induced mitochondrial dysfunction and resulted in increased cell apoptosis via inhibition of NF-κB signaling pathway and activation of JNK signaling pathway through the direct interaction of GKN2 with Hsc70. Trefoil factor 1 might contribute to the tumor suppressing effects of GKN2. MiR-216a downregulated GKN2 expression. GKN2 also inhibited xenograft tumor growth and was an independent and significant prognostic factor for patients with gastric cancer treated with oxaliplatin.ConclusionsTaken together, our data indicate that GKN2 may increase sensitivity of GC cells to the drugs which increase ROS levels in tumors. Inhibition of the interaction between GKN2 and Hsc70 could attenuate the effects induced by GKN2. GKN2 overexpression could be used to determine the subgroup of patients to obtain the more favorable outcome of oxaliplatin treatment and may be used as biomarker of the prognosis of this cancer.

Amnion epithelial cell–derived exosomes induce inflammatory changes in uterine cells

Fetal endocrine signals are generally considered to contribute to the timing of birth and the initiation of labor. Fetal tissues under oxidative stress release inflammatory mediators that lead to sterile inflammation within the maternal-fetal interface. Importantly, these inflammatory mediators are packaged into exosomes, bioactive cell-derived extra cellular vesicles that function as vectors and transport them from the fetal side to the uterine tissues where they deposit their cargo into target cells enhancing uterine inflammatory load. This exosome-mediated signaling is a novel mechanism for fetal-maternal communication. This report tested the hypothesis that oxidative stress can induce fetal amnion cells to produce exosomes, which function as a paracrine intermediary between the fetus and mother and biochemically signal readiness for parturition. Primary amnion epithelial cells were grown in normal cell culture (control) or exposed to oxidative stress conditions (induced by cigarette smoke extract). Exosomes were isolated from cell supernatant by sequential ultracentrifugation. Exosomes were quantified and characterized based on size, shape, and biochemical markers. Myometrial, decidual, and placental cells (BeWo) were treated with 2× 105, 2× 107, and 2× 109 control or oxidative stress-derived amnion epithelial cell exosomes for 24 hours. Entry of amnion epithelial cell exosomes into cells was confirmed by confocal microscopy of fluorescent-labeled exosomes. The effect of amnion epithelial cell exosomes on target cell inflammatory status was determined by measuring production of interleukin-6, interleukin-8, interleukin-1β, tumor necrosis factor-α, and prostaglandin E2 by enzyme-linked immunosorbent assay and inflammatory gene transcription factor (nuclear factor-κβ) activation status by immunoblotting for phosphorylated RelA/p65. Localization of NANOG in term human myometrium and decidua obtained from women before labor and during labor was performed using immunohistochemistry. Data were analyzed by Wilcoxon-Mann-Whitney test to compare effects of exosomes from control and oxidative stress-treated amnion epithelial cells on inflammatory status of target cells. Amnion epithelial cells released ∼125 nm, cup-shaped exosomes with ∼899 and 1211 exosomes released per cell from control and oxidative stress-induced cells, respectively. Amnion epithelial cell exosomes were detected in each target cell type after treatment using confocal microscopy. Treatment with amnion epithelial cell exosomes increased secretion of interleukin-6, interleukin-8, and PGE2 and activation of NF-κβ (each P < .05) in myometrial and decidual cells. Exosome treatments had no effect on interleukin-6 and PGE2 production in BeWo cells. NANOG staining was higher in term labor myometrium and decidua compared to tissues not in labor. Invitro, amnion epithelial cell exosomes lead to an increased inflammatory response in maternal uterine cells whereas placental cells showed refractoriness. Fetal cell exosomes may function to signal parturition by increasing maternal gestational cell inflammation.

HDAC2: a potential target for neurological diseases

Oxidative stress affects diverse biological processes, including neuron homeostasis, survival and death. Most neurological disorders, such as Alzheimer’s disease (AD), Parkinson’s disease (PD) and stroke, are associated with oxidative stress. It has been extensively investigated that FOXO3a participates in the oxidative stress-induced neuronal apoptosis. However, the function of FOXO3a complexes in oxidative stress processing remains unclear. Recently we identified FOXO3a forms complex with Histone deacetylase 1 (HDAC1) and HDAC2. Under oxidative stress stimuli, the physical interaction between FOXO3a and HDAC1 or HDAC2 was disrupted. Further neuronal apoptosis assay demonstrated that knockdown HDAC2, but not HDAC1, reduced oxidative stress-induced neuronal cell death. Mechanistically, HDAC2 is recruited onto p21 promoter by FOXO3a and deacetylates the surrounding histone at H4K16, hence regulates p21 expression, which inhibits neuronal apoptosis. In addition, we discovered that oxidative stress-mediated HDAC2 Serine 394 (S394) phosphorylation regulated FOXO3a-HDAC2 interaction. Our research suggests that HDAC2 might be therapeutic target for neuron apoptosis-related diseases, including cerebral ischemia and degenerative diseases.