scholarly journals Oxidative Stress-Mediated YAP Dysregulation Contributes to the Pathogenesis of Pemphigus Vulgaris

2021 ◽  
Vol 12 ◽  
Author(s):  
Yunying Huang ◽  
Hana Jedličková ◽  
Yang Cai ◽  
Ambreen Rehman ◽  
Luke Gammon ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Pemphigus Vulgaris ◽  
Negative Regulator ◽  
Adhesion Protein ◽  
Protein Levels ◽  
Hydrogen Peroxide Treatment ◽  
Inverse Effect ◽  
Life Threatening ◽  
Mechanical Sensor

Pemphigus Vulgaris (PV) is a life-threatening autoimmune disease manifested with blisters in the skin and mucosa and caused by autoantibodies against adhesion protein desmoglein-3 (Dsg3) expressed in epithelial membrane linings of these tissues. Despite many studies, the pathogenesis of PV remains incompletely understood. Recently we have shown Dsg3 plays a role in regulating the yes-associated protein (YAP), a co-transcription factor and mechanical sensor, and constraining reactive oxygen species (ROS). This study investigated the effect of PV sera as well as the anti-Dsg3 antibody AK23 on these molecules. We detected elevated YAP steady-state protein levels in PV cells surrounding blisters and perilesional regions and in keratinocytes treated with PV sera and AK23 with concomitant transient ROS overproduction. Cells treated with hydrogen peroxide also exhibited augmented nuclear YAP accompanied by reduction of Dsg3 and α-catenin, a negative regulator of YAP. As expected, transfection of α-catenin-GFP plasmid rendered YAP export from the nucleus evoked by hydrogen peroxide. In addition, suppression of total YAP was observed in hydrogen peroxide treated cells exposed to antioxidants with enhanced cell-cell adhesion being confirmed by decreased fragmentation in the dispase assay compared to hydrogen peroxide treatment alone. On the other hand, the expression of exogenous YAP disrupted intercellular junction assembly. In contrast, YAP depletion resulted in an inverse effect with augmented expression of junction assembly proteins, including Dsg3 and α-catenin capable of abolishing the effect of AK23 on Dsg3 expression. Finally, inhibition of other kinase pathways, including p38MAPK, also demonstrated suppression of YAP induced by hydrogen peroxide. Furthermore, antioxidant treatment of keratinocytes suppressed PV sera-induced total YAP accumulation. In conclusion, this study suggests that oxidative stress coupled with YAP dysregulation attributes to PV blistering, implying antioxidants may be beneficial in the treatment of PV.

ARNT Mediates Chemotherapy Resistance by Modulating the Response to Oxidative Stress in AML Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2737-2737
Author(s):  
Richard A. Wells ◽  
Chunhong Gu ◽  
Joelle dela Paz
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Cell Lines ◽  
Akt Signaling ◽  
Mrna Levels ◽  
Antioxidant Genes ◽  
Protein Levels ◽  
Exogenous Expression ◽  
Induction Of Apoptosis ◽  
Induced Apoptosis

Abstract Abstract 2737 Poster Board II-713 Background Although patients with acute myelogenous leukaemia (AML) typically respond well to initial therapy, with over 75% of patients achieving complete remission, in the great majority the disease ultimately relapses. This is thought to be due to the inherent resistance of leukaemia stem cells to the effects of chemotherapy. While some mechanisms of chemoresistance, e.g. TP53 mutation and upregulation of P-glycoprotein expression, have been well characterized, this phenomenon remains incompletely understood and is a significant barrier to improving patient outcomes. Methods and results The thiazolidindione drug troglitazone (TG) induces apoptosis in AML cells via generation of intracellular reactive oxygen species (ROS), but the degree of sensitivity to TG is highly heterogeneous among AML cell lines. We studied expression of the transcription factor ARNT (aryl hydrocarbon nuclear translocator) in TG-sensitive and TG-resistant AML cell lines following TG treatment. In HL-60 cells, which are highly sensitive to induction of apoptosis by TG, ARNT mRNA levels remained constant following TG treatment and ARNT protein levels markedly decreased, while in U937 cells, which are TG resistant, ARNT mRNA levels increased and ARNT protein levels remained constant. We then tested the effect of exogenous expression of ARNT on the sensitivity of HL-60 cells to TG-induced apoptosis. HL-60 cells transduced with a retrovirus expressing ARNT became TG-resistant. Exogenous expression of ARNT also conferred resistance to induction of apoptosis by hydrogen peroxide, daunorubicin and etoposide. The cellular response to oxidative stress is governed by intracellular signaling pathways and through a transcriptional response through which expression of antioxidant genes is coordinated. HL-60 cells expressing ARNT had striking constitutive activation of AKT signaling, and treatment of these cells with a specific inhibitor of AKT signaling reversed their resistance to TG-induced apoptosis. The activation of AKT signaling by ARNT appears to be mediated by downregulation of expression of PP2A and alpha4, two key negative regulators of AKT phosphorylation. In addition, ARNT-transduced HL-60 cells showed increased expression of Nrf2, a key transcriptional regulator of the antioxidant response, and its target genes SOD2 and CAT. Conclusions The response to oxidative stress is heterogeneous in AML cells lines, and varies with expression of ARNT. ARNT activates expression of Nrf2, which stimulates expression of antioxidant genes resulting in an augmented adaptive response to ROS. Unexpectedly, ARNT also activates AKT signaling by repressing expression of the regulatory phosphatases PP2A and alpha4. These activities of ARNT result in increased resistance to the induction of apoptosis by TG, hydrogen peroxide, and chemotherapy. ARNT may play an important role in chemoresistance in and may be useful as a predictive or prognostic biomarker. Disclosures: No relevant conflicts of interest to declare.

Further investigation of the mechanism of Vitreoscilla hemoglobin (VHb) protection from oxidative stress in Escherichia coli

Biologia ◽  
2011 ◽  
Vol 66 (5) ◽  
Author(s):  
Meltem Akbas ◽  
Tugrul Doruk ◽  
Serhat Ozdemir ◽  
Benjamin Stark
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Stationary Phase ◽  
Exponential Phase ◽  
Vitreoscilla Hemoglobin ◽  
Sod Activity ◽  
E Coli ◽  
Hydrogen Peroxide Treatment

AbstractIn Escherichia coli, Vitreoscilla hemoglobin (VHb) protects against oxidative stress, perhaps, in part, by oxidizing OxyR. Here this protection, specifically VHb-associated effects on superoxide dismutase (SOD) and catalase levels, was examined. Exponential or stationary phase cultures of SOD+ or SOD− E. coli strains with or without VHb and oxyR antisense were treated with 2 mM hydrogen peroxide without sublethal peroxide induction, and compared to untreated control cultures. The hydrogen peroxide treatment was toxic to both SOD+ and SOD− cells, but much more to SOD− cells; expression of VHb in SOD+ strains enhanced this toxicity. In contrast, the presence of VHb was generally associated in the SOD+ background with a modest increase in SOD activity that was not greatly affected by oxyR antisense or peroxide treatment. In both SOD+ and SOD− backgrounds, VHb was associated with higher catalase activity both in the presence and absence of peroxide. Contrary to its stimulatory effects in stationary phase, in exponential phase oxyR antisense generally decreased VHb levels.

scholarly journals Effect of Trigonella foenum graecum L on the Activities of Antioxidant Enzyme and Their Expression in Tissues of Alloxan-Induced Diabetic Rats

2015 ◽  
Vol 20 (3) ◽  
pp. 203-211 ◽  
Author(s):  
Sapneh Sharma ◽  
Vibhuti Mishra ◽  
Shiv Kumar Jayant ◽  
Nalini Srivastava
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Diabetic Rats ◽  
Control Treatment ◽  
Trigonella Foenum Graecum ◽  
Production Of Hydrogen ◽  
Life Threatening ◽  
Trigonella Foenum Graecum L ◽  
The Brain

Diabetes is a life-threatening metabolic disorder. This study was undertaken to evaluate the antihyperglycemic and antioxidative potential of seed powder of Trigonella foenum-graecum L in alloxan (55 mg/kg) induced diabetic rats. The results obtained showed that extensive oxidative stress is generated in tissues of diabetic rats as evidenced by increased production of hydrogen peroxide, increased accumulation of malondialdehyde (MDA) and 4-hydroxynonanal (4HNE) and decreased activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) in tissues of diabetic rats. It was observed that the transcription of genes of SOD, GPx, and CAT was also significantly decreased when compared with control. Treatment of Trigonella for 15 days to diabetic rats showed hypoglycemic effect and improved the altered levels of H2O2, MDA, and 4HNE, the activities of SOD, GPx, and CAT as well as transcription of these genes in the liver and the brain of diabetic rats.

scholarly journals Hydrogen Peroxide Causes Cell Death via Increased Transcription of HOXB13 in Human Lung Epithelial A549 Cells

Toxics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 78
Author(s):  
Naoki Endo ◽  
Takashi Toyama ◽  
Akira Naganuma ◽  
Yoshiro Saito ◽  
Gi-Wook Hwang
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Cell Death ◽  
Human Lung ◽  
A549 Cells ◽  
Protein Levels ◽  
Intracellular Ros ◽  
Lung Epithelial ◽  
Homeobox Protein

Although homeobox protein B13 (HOXB13) is an oncogenic transcription factor, its role in stress response has rarely been examined. We previously reported that knockdown of HOXB13 reduces the cytotoxicity caused by various oxidative stress inducers. Here, we studied the role of HOXB13 in cytotoxicity caused by hydrogen peroxide in human lung epithelial A549 cells. The knockdown of HOXB13 reduced hydrogen peroxide-induced cytotoxicity; however, this phenomenon was largely absent in the presence of antioxidants (Trolox or N-acetyl cysteine (NAC)). This suggests that HOXB13 may be involved in the cytotoxicity caused by hydrogen peroxide via the production of reactive oxygen species (ROS). Hydrogen peroxide also increased both the mRNA and protein levels of HOXB13. However, these increases were rarely observed in the presence of a transcriptional inhibitor, which suggests that hydrogen peroxide increases protein levels via increased transcription of HOXB13. Furthermore, cell death occurred in A549 cells that highly expressed HOXB13. However, this cell death was mostly inhibited by treatment with antioxidants. Taken together, our findings indicate that HOXB13 may be a novel factor involved in the induction of oxidative stress, which causes cell death via intracellular ROS production.

P–111 Development of a flow cytometric assay for membrane lipid oxidation in human sperm

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
L Bosman ◽  
P Ellis ◽  
S Homa ◽  
D Griffin
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Lipid Peroxidation ◽  
Oxidative Damage ◽  
Male Fertility ◽  
Lipid Membrane ◽  
Membrane Damage ◽  
Flow Cytometric ◽  
Hydrogen Peroxide Treatment ◽  
Lipid Peroxidation Assay

Abstract Study question Is a commercially available lipid peroxidation assay sensitive enough to detect sperm lipid membrane damage and thus provide a novel indicator of male fertility status? Summary answer Provisional results demonstrate the novelty of creating a protocol to identify and quantify sperm lipid membrane damage and indicate possible insight into individual male fertility. What is known already Cytotoxic lipid aldehydes such as 4-hydroxynonenal (4HNE) created by the damaging effects of reactive oxygen species (ROS) have been studied extensively in sperm, as an indicator of male fertility. This is due to their connection with detrimental effects on sperm function such as morphology, acrosome reactions, motility and fertilization of the oocyte. Although literature states the mechanisms of damage caused to the lipid membrane of the sperm cell, there is no evidence of its quantification or usage as a commercial fertility indicator for human males. Study design, size, duration Since the assay is still being developed, there is no formal study size or duration. The goal of this pilot study is to determine whether a commercial lipid peroxidation assay can detect the difference between sperm with high levels of oxidative damage and control sperm cells. We used the remains of sperm samples initially collected for standard semen analysis, which were flash-frozen and then assayed with / without hydrogen peroxide treatment to induce oxidative damage. Participants/materials, setting, methods Frozen sperm from consenting donors (n = 21) were washed, optionally treated with hydrogen peroxide to induce oxidative damage, stained with a commercially available lipid peroxidation sensor (LPS, Abcam ab243377), and the resulting fluorescence quantitated by flow cytometry. Assay optimization varied the numbers of sperm input to the protocol, the concentration of the peroxidation sensor, the amount and duration of hydrogen peroxide treatment and the effect of paraformaldehyde (PFA) fixation of samples before or after staining. Main results and the role of chance Successful detection of lipid damage in control samples We observed a significant difference at a p-value < 0.05 between untreated samples and all positive controls with hydrogen peroxide concentrations stronger than 500uM (p < 0.038) . This indicates that we can detect sperm bearing oxidative damage, and establishes the conditions required to make a positive control sample. Establishment of assay parameters Results indicate the concentration of sperm input to the protocol is not a significant factor for concentrations below 5 million/ml. Low concentration samples thus do not require further dilution before testing. Correlation with DNA damage A significant direct strong positive Pearson correlation coefficient (R = 0.93, p < 0.023) was found between samples with low DNA fragmentation index (DFI (%), measured by flow cytometric staining with acridine orange) and the LPS flow cytometric data (%). Limitations, reasons for caution As yet our data only addresses high level lipid damage induced by peroxide treatment. It remains to be established whether it is possible to detect endogenous LPO damage due to oxidative stress in semen. Future work will correlate our data with motility information and oxidative stress data (measured by MiOXSYS). Wider implications of the findings: If we are able to develop a direct assay for sperm LPO, this will allow an additional avenue for testing patients with unexplained male infertility, which could in turn affect treatment choices and ART methodology. Improved diagnosis and treatment will potentially improve the lives of families with their fertility matters. Trial registration number Not applicable

scholarly journals Mechanisms of Trx2/ASK1-Mediated Mitochondrial Injury in Pemphigus Vulgaris

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Bin Wei ◽  
Fenghe Li
Keyword(s):  
Oxidative Stress ◽  
Signaling Pathway ◽  
Pemphigus Vulgaris ◽  
Stress Factors ◽  
Tissue Samples ◽  
Mitochondrial Injury ◽  
Protein Levels ◽  
Thioredoxin 2

Objective. Apoptotic events mediated by mitochondrial injury play an important role on the onset of Pemphigus vulgaris (PV). The thioredoxin-2 (Trx2)/apoptosis signal-regulating kinase 1 (ASK1) signaling pathway is considered a key cascade involved on the regulation of mitochondrial injury. Hence, we have investigated the regulatory mechanism of the Trx2/ASK1 signaling in PV-induced mitochondrial injury. Methods. Serum and tissue samples were collected from clinical PV patients to detect the oxidative stress factors, cell apoptosis, and expression of members from Trx2/ASK1 signaling. HaCaT cells were cultured with the serum of PV patients and transfected with Trx2 overexpression or silencing vector. Changes in the levels of reactive oxygen species (ROS), mitochondrial membrane potential (△ψm), and apoptosis were further evaluated. A PV mouse model was established and administered with Trx2-overexpressing plasmid. The effect of ectopic Trx2 expression towards acantholysis in PV mice was observed. Results. A series of cellular and molecular effects, including (i) increased levels of oxidative stress products, (ii) destruction of epithelial cells in the skin tissues, (iii) induction of apoptosis in keratinocytes, (iv) reduction of Trx2 protein levels, and (v) enhanced phosphorylation of ASK1, were detected in PV patients. In vitro experiments confirmed that Trx2 can inhibit ASK1 phosphorylation, alleviate ROS release, decrease △ψm, and lower the apoptotic rate. Injection of Trx2-overexpressing vectors in vivo could also relieve acantholysis and blister formation in PV mice. Conclusion. The Trx2/ASK1 signaling pathway regulates the incidence of PV mediated by mitochondrial injury.

scholarly journals Lycopene Protects Cortical Neurons via Oxidative Stress-mediated ΔN-Bcl-xL Formation (FS05-08-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Allison Stumpf ◽  
Katheryn Broman ◽  
Katelyn Senkus ◽  
Libo Tan ◽  
Kristi Crowe-White ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Cortical Neurons ◽  
Antioxidant Properties ◽  
B Cell Lymphoma ◽  
Nutritional Intervention ◽  
Redox Status ◽  
Neuroprotective Effects ◽  
Protein Levels ◽  
Funding Sources

Abstract Objectives B-cell lymphoma-extra large (Bcl-xL) is a protein found in the mitochondrial membrane with anti-apoptotic properties. Bcl-xL has demonstrated neuroprotective effects by enhancing mitochondrial function. However, during oxidative stress, Bcl-xL undergoes cleavage to form pro-cell death ∆N-Bcl-xL. Accumulation of ∆N-Bcl-xL causes abnormal mitochondrial channel activity associated with neuronal death. Therefore, strategies that prevent formation of ∆N-Bcl-xL protect the brain. In this study, we hypothesize that cleavage of Bcl-xL can be controlled by nutritional intervention. We test if treatment with lycopene, a potent antioxidant with neuroprotective effects, can protect primary neurons via improving intracellular redox status by reducing production of ∆N-Bcl-xL. Methods Primary cortical neurons were treated with lycopene, hydrogen peroxide (a ROS donor), or both. Levels of superoxide, cell viability and cytotoxicity, and protein levels of Bcl-xL and ∆N-Bcl-xL were quantified. Results Hydrogen peroxide increased cytotoxicity while treatment with lycopene protected oxidative stress-induced cortical death. Lycopene prevented N-terminal cleavage of Bcl-xL and thus inhibited formation of ∆N-Bcl-xL. Conclusions These data show that the formation of ∆N-Bcl-xL is induced in part by reactive oxygen species and high levels of oxidative stress. The antioxidant properties of lycopene help reduce oxidative stress and prevent cleavage of Bcl-xL to ∆N-Bcl-xL, thus maintaining an anti-apoptotic environment. Funding Sources RG14811.

scholarly journals OxyR and SoxR Modulate the Inducible Oxidative Stress Response and Are Implicated During Different Stages of Infection for the Bacterial Phytopathogen Pantoea stewartii subsp. stewartii

2014 ◽  
Vol 27 (5) ◽  
pp. 479-490 ◽  
Author(s):  
Lindsey Burbank ◽  
M. Caroline Roper
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Stress Response ◽  
Plant Pathogens ◽  
Sweet Corn ◽  
Bacterial Pathogen ◽  
Infection Process ◽  
Pantoea Stewartii ◽  
Hydrogen Peroxide Treatment ◽  
Stewart's Wilt

Reactive oxygen species (ROS) from a variety of sources are often encountered by invading plant pathogens during the infection process. Pantoea stewartii subsp. stewartii, the etiological agent of Stewart's wilt, is a serious bacterial pathogen of sweet corn that colonizes both the apoplast and xylem tissues in which ROS are produced. The P. stewartii genome predicts the presence of two redox-sensing transcriptional regulators, OxyR and SoxR, which both activate gene expression in response to oxidative stress. ROS exposure in the form of hydrogen peroxide and the superoxide-generating compound paraquat initiates an induced stress response through OxyR and SoxR that includes activation of the ROS-detoxifying enzymes alkyl hydroperoxide reductase and superoxide dismutase. P. stewartii ΔsoxR was more sensitive to paraquat and was compromised in the ability to form water-soaked lesions, while ΔoxyR was more sensitive to hydrogen peroxide treatment and was deficient in exopolysaccharide production and the elicitation of wilting symptoms. This demonstrates that both SoxR and OxyR play an important role in virulence in the different niches that P. stewartii colonize during the infection process.

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