Reactive Oxygen Species Pathway Research Articles

Transcript Dynamics in Wounded and Inoculated Scots Pine

Comparative transcriptome analysis provides a useful tool for the exploration of plant–pathogen interaction by allowing in-depth comparison of gene expression between unaffected, inoculated and wounded organisms. Here we present the results of comparative transcriptome analysis in genetically identical one-year-old Scots pine ramets after wounding and inoculation with Heterobasidion annosum. We identified 230 genes that were more than 2-fold upregulated in inoculated samples (compared to controls) and 116 downregulated genes. Comparison of inoculated samp les with wounded samples identified 32 differentially expressed genes (30 were upregulated after inoculation). Several of the genes upregulated after inoculation are involved in protection from oxidative stress, while genes involved in photosynthesis, water transport and drought stress tolerance were downregulated. An NRT3 family protein was the most upregulated transcript in response to both inoculation and wounding, while a U-box domain-containing protein gene was the most upregulated gene comparing inoculation to wounding. The observed transcriptome dynamics suggest involvement of auxin, ethylene, jasmonate, gibberellin and reactive oxygen species pathways and cell wall modification regulation in response to H. annosum infection. The results are compared to methyl jasmonate induced transcriptome dynamics.

Education on reactive oxygen species to lay the foundation for understanding therapeutic advances in anticancer therapy.

478 Background: The disruption of redox balance is increasingly thought to be one of the most important underlying factors contributing to the development, progression, and metastasis of cancers in human cells. This imbalance in redox homeostasis has been shown to be induced by the generation of free radicals, predominantly reactive oxygen species (ROS). Emerging data have established ROS as a new potential therapeutic target. Understanding the mechanisms associated with tumorigenesis is important to integrate novel potential therapeutic targets and understand which tumors or patient populations may benefit from ongoing research. Shortcomings in oncologists’ knowledge and confidence can hamper the integration of new treatments into the care of patients with cancer. Methods: An online continuing education (CME) activity consisted of a multi-media 30-minute video panel of two panelists discussing the mechanism, pathophysiology, and the premises for novel anti-cancer therapies. Educational effect was assessed using a repeated paired pre-/post-assessment study design. A McNemar’s test was used to identify differences between pre- and post-assessment responses. Effect size was calculated using Cohen’s d test by determining the strength of the association between the activity and the outcomes (d < .20 is modest and d ≥ .80 is large). P values were calculated and those < .05 were considered statistically significant. The activity launched 5/14/2020 and data are represented through 8/6/2020. Results: A total of 1,033 learners, of which there are 656 physicians, participated in the activity. Participating in education resulted in statistically significant improvements and noticeable educational effect and data for oncologists that answered all pre- and post-assessment questions are represented below (n = 45, p < .001, Cohen’s d = .454). Percentages represent relative rates of improvement The role of ROS on cancer cell proliferation, cancer cell toxicity, and the tumor microenvironment (67%, p < .05) The interplay of antioxidants to aid in the development of therapies to induce DNA-damaged cell death (100%; p < .001) The potential biomarkers to aid in the development of therapies to induce DNA-damaged cell death (34%; p < .05). Conclusions: This online, interactive, expert-led, CME-certified educational activity resulted in significant gains in oncologist knowledge and confidence regarding the ROS pathway and associated clinical pipeline developments Upon completion of the initiative, only 11% of oncologists were able to answer all 3 matched pre/post questions correctly, signifying the need for further education The novelty of the information to many learners demonstrate the need to continue highlighting clinical advances and molecular pathways that may have potential implications in cancer therapy progress.

Planthopper-Secreted Salivary Disulfide Isomerase Activates Immune Responses in Plants.

The small brown planthopper (Laodelphax striatellus; SBPH) is a piercing-sucking insect that secretes salivary proteins into its plant host during feeding. However, the mechanisms by which these salivary proteins regulate plant defense responses remain poorly understood. Here, we identified the disulfide isomerase (LsPDI1) in the SBPH salivary proteome. LsPDI1 was highly expressed in the SBPH salivary glands and secreted into rice plants during feeding. Transient in planta LsPDI1 expression in the absence of signal peptide induced reactive oxygen species (ROS) burst, cell death, callose deposition, and jasmonic acid (JA) signaling pathway. Deletion mutant analysis revealed that either the a-b-b’ or the b-b’-a’ domains in LsPDI1 are required to induce cell death in plants. LsPDI1 and its orthologs were highly conserved among various planthopper species and strongly induced ROS burst and cell death in plants. Transient in Nicotiana benthamiana LsPDI1 expression impaired the performance of Spodoptera frugiperda and Myzus persicae on host plants. Hence, LsPDI1 is an important salivary elicitor that enhances plant resistance to insects by inducing the calcium, ROS, and JA signaling pathways. The findings of this study provide novel insights into the molecular mechanisms underlying plant-insect interactions.

NLRP3 Inflammasome Blockade Reduces Cocaine-Induced Microglial Activation and Neuroinflammation.

Cocaine use disorder is a major health crisis that is associated with increased oxidative stress and neuroinflammation. While the role of NLRP3 inflammasome in mediating neuroinflammation is well-recognized, whether cocaine induces this response remains unexplored. Based on the premise that cocaine induces both reactive oxygen species (ROS) as well as microglial activation, we hypothesized that cocaine-mediated microglial activation involves both ROS and NLRP3 signaling pathways. We examined activation of the NLRP3 pathway in microglia exposed to cocaine, followed by validation in mice administered either cocaine or saline for 7 days, with or without pretreatment with the NLRP3 inhibitor, MCC950, and in postmortem cortical brain tissues of chronic cocaine-dependent humans. We found that microglia exposed to cocaine exhibited significant induction of NLRP3 and mature IL-1β expression. Intriguingly, blockade of ROS (Tempol) attenuated cocaine-mediated priming of NLRP3 and microglial activation (CD11b). Blockade of NLRP3 by both pharmacological (MCC950) as well as gene silencing (siNLRP3) approaches underpinned the critical role of NLRP3 in cocaine-mediated activation of inflammasome and microglial activation. Pretreatment of mice with MCC950 followed by cocaine administration for 7 days mitigated cocaine-mediated upregulation of mature IL-1β and CD11b, in both the striatum and the cortical regions. Furthermore, cortical brain tissues of chronic cocaine-dependent humans also exhibited upregulated expression of the NLRP3 pathway mediators compared with non-cocaine dependent controls. Collectively, these findings suggest that cocaine activates microglia involving the NLRP3 inflammasome pathway, thereby contributing to neuroinflammation. NLRP3 can thus be considered as a potential therapeutic target for alleviating cocaine-mediated neuroinflammation.

Construction of a nine DNA repair-related gene prognostic classifier to predict prognosis in patients with endometrial carcinoma

BackgroundEndometrial cancer (EC) is one of the most common gynecological malignancies worldwide. However, the molecular mechanisms and the prognostic prediction for EC patients remain unclear.MethodsIn the current study, we performed an in-depth analysis of over 500 patients which were obtained from the Cancer Genome Atlas (TCGA) database. The bioinformatics analysis included gene set enrichment analysis (GSEA) and Cox and lasso regression analyses to ensure overall survival (OS)-related genes, moreover, to construct a prognostic model and a nomogram for EC patients.ResultsGSEA identified 4 gene sets significantly associated with EC, which are DNA repair, unfolded protein response, reactive oxygen species pathway and UV response up. Twenty-five OS-related DNA repair genes were screened out, after that, a 9-mRNA signature was constructed to measure the risk scores of patients with different outcomes. In addition, a nomogram contained the 9-mRNA model and clinical parameters was also presented to assess the prognosis. Patients with low risk were more likely to have sensitivity to paclitaxel, vinblastine, rapamycin, metformin, imatinib, Akt inhibitor and lapatinib.ConclusionsThe identified highly enriched gene sets may offer a novel insight into the tumorigenesis and treatment of EC. Additionally, the constructed 9-mRNA model and the nomogram have prominent clinical implications for prognosis evaluation and specific therapy guidance for EC patients.

ROS Pleiotropy in Melanoma and Local Therapy with Physical Modalities.

Metabolic energy production naturally generates unwanted products such as reactive oxygen species (ROS), causing oxidative damage. Oxidative damage has been linked to several pathologies, including diabetes, premature aging, neurodegenerative diseases, and cancer. ROS were therefore originally anticipated as an imperative evil, a product of an imperfect system. More recently, however, the role of ROS in signaling and tumor treatment is increasingly acknowledged. This review addresses the main types, sources, and pathways of ROS in melanoma by linking their pleiotropic roles in antioxidant and oxidant regulation, hypoxia, metabolism, and cell death. In addition, the implications of ROS in various physical therapy modalities targeting melanoma, such as radiotherapy, electrochemotherapy, hyperthermia, photodynamic therapy, and medical gas plasma, are also discussed. By including ROS in the main picture of melanoma skin cancer and as an integral part of cancer therapies, a greater understanding of melanoma cell biology is presented, which ultimately may elucidate additional clues on targeting therapy resistance of this most deadly form of skin cancer.

A homologous-targeting "nanoconverter" with variable size for deep tumor penetration and immunotherapy.

Tumor-associated immunosuppression, as a key barrier, prevents immunotherapy-resistant tumors. In this study, an ingenious "nanoconverter" was designed to convert immunosuppression into immunoactivation, which was a C6-ceramide (C6)-modified tumor cytomembrane-coated polydopamine-paclitaxel system (PTX/PDA@M-C6). The co-administration of C6-ceramide and tumor cytomembrane changed an adaptive immune state to an activation state, which induced a robust antigen presentation ability of tumor-infiltrating dendritic cells to activate T1 helper cells and cytotoxic T lymphocytes. Meanwhile, C6-ceramide regulated the phenotype of macrophages via the reactive oxygen species pathway, which resulted in the conversion of M2-like macrophages by infiltration within tumors into M2-like macrophages, and therefore, M2-like macrophage-mediated immunosuppression was weakened distinctly. The "nanoconverter"-mediated conversion process upregulated the expression of related immune factors including interleukin-12, interleukin-6, tumor necrosis factor-α and interferon-γ and executed positive anti-tumor effects. In addition, under the protection of tumor-homologous cytomembrane, the "nanoconverter" exhibited excellent delivery efficiency (23.22%), and subsequently, accumulated special structural "nanoconverter" could break down into smaller nanoparticles for deep penetration into the tumor tissue under a NIR laser. Ultimately, chemo/thermal therapy-assisted immunotherapy completely eliminated the tumors of tumor-bearing mice, and a potent memory response relying on effector memory T cells still persisted to protect against tumor relapse after the end of treatment. The "nanoconverter" serves as a promising nanodrug delivery system for the conversion of immunosuppression and enhanced chemo/thermal therapy. Therefore, the highly cumulative "nanoconverter" has great potential for promoting the effect and clinical application of immunotherapy.

A Marine Terpenoid, Heteronemin, Induces Both the Apoptosis and Ferroptosis of Hepatocellular Carcinoma Cells and Involves the ROS and MAPK Pathways.

Hepatocellular carcinoma (HCC) is a leading cause of death, resulting in over 700 thousand deaths annually worldwide. Chemotherapy is the primary therapeutic strategy for patients with late-stage HCC. Heteronemin is a marine natural product isolated from Hippospongia sp. that has been found to protect against carcinogenesis in cholangiocarcinoma, prostate cancer, and acute myeloid leukemia. In this study, heteronemin was found to inhibit the proliferation of the HCC cell lines HA22T and HA59T and induce apoptosis via the caspase pathway. Heteronemin treatment also induced the formation of reactive oxygen species (ROS), which are associated with heteronemin-induced cell death, and to trigger ROS removal by mitochondrial SOD2 rather than cytosolic SOD1. The mitogen-activated protein kinase (MAPK) signaling pathway was associated with ROS-induced cell death, and heteronemin downregulated the expression of ERK, a MAPK that is associated with cell proliferation. Inhibitors of JNK and p38, which are MAPKs associated with apoptosis, restored heteronemin-induced cell death. In addition, heteronemin treatment reduced the expression of GPX4, a protein that inhibits ferroptosis, which is a novel form of nonapoptotic programmed cell death. Ferroptosis inhibitor treatment also restored heteronemin-induced cell death. Thus, with appropriate structural modification, heteronemin can act as a potent therapeutic against HCC.

Reactive Oxygen Species as a Link between Antioxidant Pathways and Autophagy.

Reactive oxygen species (ROS) are highly reactive molecules that can oxidize proteins, lipids, and DNA. Under physiological conditions, ROS are mainly generated in the mitochondria during aerobic metabolism. Under pathological conditions, excessive ROS disrupt cellular homeostasis. High levels of ROS result in severe oxidative damage to the cellular machinery. However, a low/mild level of ROS could serve as a signal to trigger cell survival mechanisms. To prevent and cope with oxidative damage to biomolecules, cells have developed various antioxidant and detoxifying mechanisms. Meanwhile, ROS can initiate autophagy, a process of self-clearance, which helps to reduce oxidative damage by engulfing and degrading oxidized substance. This review summarizes the interactions among ROS, autophagy, and antioxidant pathways. The effects of natural phytochemicals on autophagy induction, antioxidation, and dual-function are also discussed.

Mitophagy-mediated adipose inflammation contributes to type 2 diabetes with hepatic insulin resistance.

White adipose tissues (WAT) play crucial roles in maintaining whole-body energy homeostasis, and their dysfunction can contribute to hepatic insulin resistance and type 2 diabetes mellitus (T2DM). However, the mechanisms underlying these alterations remain unknown. By analyzing the transcriptome landscape in human adipocytes based on available RNA-seq datasets from lean, obese, and T2DM patients, we reveal elevated mitochondrial reactive oxygen species (ROS) pathway and NF-κB signaling with altered fatty acid metabolism in T2DM adipocytes. Mice with adipose-specific deletion of mitochondrial redox Trx2 develop hyperglycemia, hepatic insulin resistance, and hepatic steatosis. Trx2-deficient WAT exhibited excessive mitophagy, increased inflammation, and lipolysis. Mechanistically, mitophagy was induced through increasing ROS generation and NF-κB-dependent accumulation of autophagy receptor p62/SQSTM1, which recruits damaged mitochondria with polyubiquitin chains. Importantly, administration of ROS scavenger or NF-κB inhibitor ameliorates glucose and lipid metabolic disorders and T2DM progression in mice. Taken together, this study reveals a previously unrecognized mechanism linking mitophagy-mediated adipose inflammation to T2DM with hepatic insulin resistance.

Betel Nut Arecoline Induces Different Phases of Growth Arrest between Normal and Cancerous Prostate Cells through the Reactive Oxygen Species Pathway.

Prostate cancer (PCa) is a reproductive system cancer in elderly men. We investigated the effects of betel nut arecoline on the growth of normal and cancerous prostate cells. Normal RWPE-1 prostate epithelial cells, androgen-independent PC-3 PCa cells, and androgen-dependent LNCaP PCa cells were used. Arecoline inhibited their growth in dose- and time-dependent manners. Arecoline caused RWPE-1 and PC-3 cell cycle arrest in the G2/M phase and LNCaP cell arrest in the G0/G1 phase. In RWPE-1 cells, arecoline increased the expression of cyclin-dependent kinase (CDK)-1, p21, and cyclins B1 and D3, decreased the expression of CDK2, and had no effects on CDK4 and cyclin D1 expression. In PC-3 cells, arecoline decreased CDK1, CDK2, CDK4, p21, p27, and cyclin D1 and D3 protein expression and increased cyclin B1 protein expression. In LNCaP cells, arecoline decreased CDK2, CDK4, and cyclin D1 expression; increased p21, p27, and cyclin D3 expression; had no effects on CDK1 and cyclin B1 expression. The antioxidant N-acetylcysteine blocked the arecoline-induced increase in reactive oxygen species production, decreased cell viability, altered the cell cycle, and changed the cell cycle regulatory protein levels. Thus, arecoline oxidant exerts differential effects on the cell cycle through modulations of regulatory proteins.

NOx synthesis by atmospheric‐pressure N2/O2 filamentary DBD plasma over water: Physicochemical mechanisms of plasma–liquid interactions

AbstractIn this study, an atmospheric‐pressure filamentary dielectric barrier discharge plasma is produced over a deionized (DI) water surface to study the physicochemical mechanisms of plasma–liquid surface interactions for NOx synthesis. The gas‐phase plasma diagnostics are performed using optical emission spectroscopy, Fourier‐transform infrared spectroscopy, and by recording voltage–current curves, and liquid‐phase species are analyzed using ion chromatography and UV−visible spectrophotometer. The investigations indicate that the reaction pathways for reactive oxygen and nitrogen species (H2O2, , ) formation in DI water depend on different experimental conditions. It is observed that the conversion of nitrites into nitrates is significantly influenced by reactive oxygen species. The energy yield for the total amount of NOx synthesized ranges from 1.3 × 10−4 to 3.4 × 10−3 mol/MJ.

Cadmium and molybdenum co-exposure triggers autophagy via CYP450s/ROS pathway in duck renal tubular epithelial cells

Cadmium (Cd) and excessive molybdenum (Mo) are detrimental to animals, but the combined nephrotoxic impacts of Cd and Mo on duck are still unclear. To evaluate the combined impacts of Cd and Mo on autophagy via Cytochrome P450s (CYP450s)/reactive oxygen species (ROS) pathway, duck renal tubular epithelial cells were treated with 3CdSO4·8H2O (4.0 μM Cd), (NH4)6Mo7O24·4H2O (500.0 μM Mo), butylated hydroxy anisole (BHA) (100.0 μM) and combination of Cd and Mo or Cd, Mo and BHA for 12 h, and combined cytotoxicity was investigated. The results indicated that Mo or/and Cd induced CYP1A1, CYP1B1, CYP2C9, CYP3A8 and CYP4B1 mRNA levels, decreased superoxide dismutase (SOD), catalase (CAT) activities and glutathione peroxidase (GSH-Px) content, and increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents. Besides, Mo or/and Cd elevated the number of autophagosome and microtubule-associated protein light chain 3 (LC3) puncta, upregulated mRNA levels of Beclin-1, LC3A, LC3B, Atg5 and adenosine 5′-monophosphate (AMP)-activated protein kinase α1 (AMPKα-1), inhibited Dynein, p62 and mammalian target of rapamycin (mTOR) mRNA levels, increased Beclin-1 and LC3II/LC3I protein levels. Moreover, the changes of these factors in Mo and Cd co-treated groups were more apparent. Additionally, BHA could efficiently alleviate the changes of above these indicators co-induced by Mo and Cd. Overall, these results manifest Cd and Mo co-exposure may synergistically trigger autophagy via CYP450s/ROS pathway in duck renal tubular epithelial cells.

Genetic Silencing of KEAP1 Induces NRF2 Mediated Oxidative Stress Pathway in Human Erythroid Cells

Sickle cell disease (SCD) is a monogenic hereditary disorder resulting from a mutation in the β-globin gene which renders the red blood cells (RBCs) prone to sickling and hemolysis. SCD is characterized by several severe pathophysiologies including anemia, chest pain, stroke and vaso-occlusive crisis (VOC). Hemolysis has been attributed as one of the major contributing factors to these pathologies and has been linked to oxidative stress in RBCs that carry high levels of pro-oxidant heme. Additionally, sickle RBCs have an increased rate of auto-oxidation cycle that results in production of superoxide. Other factors including deformation and subsequent physical stress on the membrane during transit through narrow capillaries aggravate lipid peroxidation mediated damage. Therapies that can improve the antioxidant status and overall RBC health may offer a protective effect in this disease. NRF2 is a transcription factor that orchestrates activation of antioxidant genes in response to oxidative stress. We previously showed that genetic activation of NRF2 by KEAP1 knockout in HUDEP-2 and primary CD34+ cells induces fetal hemoglobin (HbF) levels and elicits a protective effect against oxidative stress in-vitro (Gupta et al. 2019). In this study, we employed the KEAP1 knockout HUDEP-2 and primary CD34+ cells to induce NRF2 pathway and subjected them to a systemic multi-omics analysis to identify key genes that are implicated in oxidative stress defense mechanisms. KEAP1 KO HUDEP-2 cells were subjected to RNA sequencing and proteomics profiling and the results were analyzed using gene set enrichment analysis (GSEA) and ingenuity pathway analysis (IPA). IPA analysis in RNA seq results showed association with NRF2 mediated oxidative stress and heme Biosynthesis II pathways. Global proteomic profiling was carried in HUDEP KEAP1 KO populations using TMT-label based peptide quantitation. Top hallmark gene sets by GSEA in proteomics analysis included reactive oxygen species pathway, xenobiotic metabolism and oxidative phosphorylation. Some of the top genes included NQO1, GSR, TXNRD1 and GCLM. In order to confirm the findings in primary CD34+ cells, a CRISPR Cas9 RNP mediated approach was used to knockout KEAP1. Two guide RNA targeting KEAP1, in two different healthy donors were employed for RNA seq and proteomics analysis. KEAP1 KO CD34+ cells were subjected to erythroid differentiation and samples were harvested for RNA seq on day 5 and proteomics on day 7 of differentiation. IPA analysis of RNA seq results showed positive enrichment of NRF2 mediated oxidative stress responses, aryl hydrocarbon receptor signaling and xenobiotic general signaling pathway. Some of the top genes regulated in CD34+ cells included NQO1, OSGIN1, GCLM, GSR, HMOX-1 and TXNRD1. Global proteomic profiling followed by IPA analysis showed association with pathways including NRF2 mediated oxidative stress pathway and xenobiotic metabolism. Furthermore, genes including NQO1, GCLM, GSR, HMOX-1 and TXNRD1 were confirmed to be upregulated by proteomics. Both, RNA seq and proteomics data confirmed the upregulation of HBG1/2 and downregulation of KEAP1, and moreover, IPA analysis of both the data sets confirmed NRF2 as the upstream regulator. In order to evaluate the functional effects of multi-omics data, KEAP1 KO CD34+ cells were subjected to hydrogen peroxide treatment and reactive oxygen species (ROS) levels were measured. Relative to control populations, KEAP1 KO cells showed attenuated response in ROS generation indicative of a protective effect against oxidative stress. Overall, these results provide a mechanistic insight towards the improvement of antioxidant status of erythroid populations with KEAP1 silencing that can be helpful in bolstering the red blood cell antioxidant responses. Improvement in antioxidant status can reduce the propensity to hemolyze and further, provides strong evidence towards NRF2 as a therapeutic target in SCD. Disclosures Gupta: Sanofi: Current Employment. Lessard:Sanofi: Current Employment. Dai:Sanofi: Current Employment. Hicks:Sanofi: Current Employment. Krishnamoorthy:Sanofi: Current Employment.

Astaxanthin protects oxidative stress mediated DNA damage and enhances longevity in Saccharomyces cerevisiae.

Reactive oxygen species (ROS) have long been found to play an important role in oxidative mediated DNA damage. Fortunately, cells possess an antioxidant system that can neutralize ROS. However, oxidative stress occurs when antioxidants are overwhelmed by ROS or impaired antioxidant pathways. This study was carried out to find the protective effect of astaxanthin on the yeast DNA repair-deficient mutant cells under hydrogen peroxide stress. The results showed that astaxanthin enhances the percent cell growth of rad1∆, rad51∆, apn1∆, apn2∆ and ogg1∆ cells. Further, the spot test and colony-forming unit count results confirmed that astaxanthin protects DNA repair mutant cells from oxidative stress. The DNA binding property of astaxanthin studied by in silico and in vitro methods indicated that astaxanthin binds to the DNA in the major and minor groove, and that might protect DNA against oxidative stress induced by Fenton's reagent. The intracellular ROS, 8-OHdG level and the DNA fragmentation as measured by comet tail was reduced by astaxanthin under oxidative stress. Similarly, reduced nuclear fragmentation and chromatin condensation results suggest that astaxanthin might reduce apoptosis. Finally, we show that astaxanthin decreases the accumulation of mutation rate and enhances the longevity of DNA repair-deficient mutants' cells during a chronological lifespan.

Thioredoxins: Emerging Players in the Regulation of Protein S-Nitrosation in Plants.

S-nitrosation has been recognized as an important mechanism of ubiquitous posttranslational modification of proteins on the basis of the attachment of the nitroso group to cysteine thiols. Reversible S-nitrosation, similarly to other redox-based modifications of protein thiols, has a profound effect on protein structure and activity and is considered as a convergence of signaling pathways of reactive nitrogen and oxygen species. This review summarizes the current knowledge on the emerging role of the thioredoxin-thioredoxin reductase (TRXR-TRX) system in protein denitrosation. Important advances have been recently achieved on plant thioredoxins (TRXs) and their properties, regulation, and functions in the control of protein S-nitrosation in plant root development, translation of photosynthetic light harvesting proteins, and immune responses. Future studies of plants with down- and upregulated TRXs together with the application of genomics and proteomics approaches will contribute to obtain new insights into plant S-nitrosothiol metabolism and its regulation.

Trimethylamine N-Oxide increases soluble fms-like tyrosine Kinase-1 in human placenta via NADPH oxidase dependent ROS accumulation

BackgroundsPreeclampsia (PE) is characterized as placental vascular disturbance and excessive secretion of soluble fms-like tyrosine kinase 1 (sFlt-1) into the maternal circulation. Trimethylamine N-oxide (TMAO, a gut microbe-derived metabolite) is strongly associated with various cardiovascular and cerebrovascular diseases. Recently, we observe that higher maternal circulating TMAO and sFlt-1 in patients with PE. The aims of the present study are to explore the effects of TMAO on placental sFlt-1 production and the underlying mechanism in human placenta. MethodsHuman placental explants, human placental primary trophoblasts and the extravillous trophoblasts (EVT) cell line (HRT-8/SVneo) were exposured to various concentrations of TMAO (100, 150, 300, and 600 μM). The mRNA expression and protein secretion of sFlt-1 in placental explants, primary trophoblasts and HRT-8/SVneo cells were determined with qPCR and ELISA, respectively. The levels of intracellular reactive oxygen species (ROS) production in primary trophoblasts and HRT-8/SVneo cells were measured by peroxide-sensitive fluorescent probe dichlorofluorescein diacetate. ResultsExposure of placental explants, primary trophoblasts and HRT-8/SVneo cells to TMAO significantly enhanced sFlt-1 at both mRNA and protein levels in a dose dependent manner. Moreover, inhibition of NADPH oxidase with apocynin significantly attenuated TMAO-induced ROS production in primary trophoblasts and HRT-8/SVneo, and suppressed sFlt-1 secretion in placental explants, primary trophoblasts and HRT-8/SVneo. ConclusionsOur findings indicated the NADPH oxidase dependent ROS pathway played a critical role in mediating TMAO-induced sFlt-1 generation in human placenta. TMAO may become a potential novel target for pharmacological or dietary interventions to reduce the risk of developing PE.

Modifying macrophages at the periphery has the capacity to change microglial reactivity and to extend ALS survival.

Microglia and peripheral macrophages have both been implicated in amyotrophic lateral sclerosis (ALS), although their respective roles have yet to be determined. We now show that macrophages along peripheral motor neuron axons in mouse models and patients with ALS react to neurodegeneration. In ALS mice, peripheral myeloid cell infiltration into the spinal cord was limited and depended on disease duration. Targeted gene modulation of the reactive oxygen species pathway in peripheral myeloid cells of ALS mice, using cell replacement, reduced both peripheral macrophage and microglial activation, delayed symptoms and increased survival. Transcriptomics revealed that sciatic nerve macrophages and microglia reacted differently to neurodegeneration, with abrupt temporal changes in macrophages and progressive, unidirectional activation in microglia. Modifying peripheral macrophages suppressed proinflammatory microglial responses, with a shift toward neuronal support. Thus, modifying macrophages at the periphery has the capacity to influence disease progression and may be of therapeutic value for ALS.

DCAF1 regulates Treg senescence via the ROS axis during immunological aging.

As a hallmark of immunological aging, low-grade, chronic inflammation with accumulation of effector memory T cells contributes to increased susceptibility to many aging-related diseases. While the proinflammatory state of aged T cells indicates a dysregulation of immune homeostasis, whether and how aging drives regulatory T cell (Treg) aging and alters Treg function are not fully understood owing to a lack of specific aging markers. Here, by a combination of cellular, molecular, and bioinformatic approaches, we discovered that Tregs senesce more severely than conventional T (Tconv) cells during aging. We found that Tregs from aged mice were less efficient than young Tregs in suppressing Tconv cell function in an inflammatory bowel disease model and in preventing Tconv cell aging in an irradiation-induced aging model. Furthermore, we revealed that DDB1- and CUL4-associated factor 1 (DCAF1) was downregulated in aged Tregs and was critical to restrain Treg aging via reactive oxygen species (ROS) regulated by glutathione-S-transferase P (GSTP1). Importantly, interfering with GSTP1 and ROS pathways reinvigorated the proliferation and function of aged Tregs. Therefore, our studies uncover an important role of the DCAF1/GSTP1/ROS axis in Treg senescence, which leads to uncontrolled inflammation and immunological aging.

All-trans retinoic acid increases ARPE-19 cell apoptosis via activation of reactive oxygen species and endoplasmic reticulum stress pathways

To explore the apoptosis of ARPE-19 cells after the treatment with different doses of all-trans-retinoic acid (ATRA). ARPE-19 cells were used in the in-vitro experiment. Flow cytometry assay was employed to evaluate the level of reactive oxygen species (ROS) and apoptosis. The effects of ATRA (concentrations from 2.5 to 20 µmol/L) on the expression of endoplasmic reticulum stress (ERS) markers in vitro were evaluated by Western blot and real-time quantitative polymerase chain reaction (qRT-PCR) assays. The contribution of ROS and ERS-induced apoptosis in vitro was determined by using N-acetyl-L-cysteine (NAC) and Salubrinal, an antagonist of NAC and ERS, respectively. Flow cytometry showed that ATRA significantly increased ARPE-19 cell apoptosis and ROS levels in each group (F=86.39, P<0.001; F=116.839, P<0.001). Western blot and qRT-PCR revealed that levels of CHOP and BIP were elevated in a concentration-dependent pattern after the cells were incubated with ATRA (2.5-20 µmol/L). The upregulation of VEGF-A and CHOP induced by ATRA could be inhibited by NAC (antioxidant) and Salubrinal (ERS inhibitor) in vitro. ATRA induces the apoptosis of ARPE-19 cells via activated ROS and ERS signaling pathways.