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Supruniuk, Elżbieta, Jan Górski i Adrian Chabowski. "Endogenous and Exogenous Antioxidants in Skeletal Muscle Fatigue Development during Exercise". Antioxidants 12, nr 2 (16.02.2023): 501. http://dx.doi.org/10.3390/antiox12020501.
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Muscle fatigue is defined as a decrease in maximal force or power generated in response to contractile activity, and it is a risk factor for the development of musculoskeletal injuries. One of the many stressors imposed on skeletal muscle through exercise is the increased production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), which intensifies as a function of exercise intensity and duration. Exposure to ROS/RNS can affect Na+/K+-ATPase activity, intramyofibrillar calcium turnover and sensitivity, and actin–myosin kinetics to reduce muscle force production. On the other hand, low ROS/RNS concentrations can likely upregulate an array of cellular adaptative responses related to mitochondrial biogenesis, glucose transport and muscle hypertrophy. Consequently, growing evidence suggests that exogenous antioxidant supplementation might hamper exercise-engendering upregulation in the signaling pathways of mitogen-activated protein kinases (MAPKs), peroxisome-proliferator activated co-activator 1α (PGC-1α), or mammalian target of rapamycin (mTOR). Ultimately, both high (exercise-induced) and low (antioxidant intervention) ROS concentrations can trigger beneficial responses as long as they do not override the threshold range for redox balance. The mechanisms underlying the two faces of ROS/RNS in exercise, as well as the role of antioxidants in muscle fatigue, are presented in detail in this review.
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Lu, Qing-Bin. "Reaction Cycles of Halogen Species in the Immune Defense: Implications for Human Health and Diseases and the Pathology and Treatment of COVID-19". Cells 9, nr 6 (13.06.2020): 1461. http://dx.doi.org/10.3390/cells9061461.
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There is no vaccine or specific antiviral treatment for COVID-19, which is causing a global pandemic. One current focus is drug repurposing research, but those drugs have limited therapeutic efficacies and known adverse effects. The pathology of COVID-19 is essentially unknown. Without this understanding, it is challenging to discover a successful treatment to be approved for clinical use. This paper addresses several key biological processes of reactive oxygen, halogen and nitrogen species (ROS, RHS and RNS) that play crucial physiological roles in organisms from plants to humans. These include why superoxide dismutases, the enzymes to catalyze the formation of H2O2, are required for protecting ROS-induced injury in cell metabolism, why the amount of ROS/RNS produced by ionizing radiation at clinically relevant doses is ~1000 fold lower than the endogenous ROS/RNS level routinely produced in the cell and why a low level of endogenous RHS plays a crucial role in phagocytosis for immune defense. Herein we propose a plausible amplification mechanism in immune defense: ozone-depleting-like halogen cyclic reactions enhancing RHS effects are responsible for all the mentioned physiological functions, which are activated by H2O2 and deactivated by NO signaling molecule. Our results show that the reaction cycles can be repeated thousands of times and amplify the RHS pathogen-killing (defense) effects by 100,000 fold in phagocytosis, resembling the cyclic ozone-depleting reactions in the stratosphere. It is unraveled that H2O2 is a required protective signaling molecule (angel) in the defense system for human health and its dysfunction can cause many diseases or conditions such as autoimmune disorders, aging and cancer. We also identify a class of potent drugs for effective treatment of invading pathogens such as HIV and SARS-CoV-2 (COVID-19), cancer and other diseases, and provide a molecular mechanism of action of the drugs or candidates.
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Sharma, Ajay Kumar, Harshit Singh i Harinath Chakrapani. "Photocontrolled endogenous reactive oxygen species (ROS) generation". Chemical Communications 55, nr 36 (2019): 5259–62. http://dx.doi.org/10.1039/c9cc01747j.
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Pan, Zhixiang, Jun Zhang, Kaili Ji, Vayou Chittavong, Xingyue Ji i Binghe Wang. "Organic CO Prodrugs Activated by Endogenous ROS". Organic Letters 20, nr 1 (7.11.2017): 8–11. http://dx.doi.org/10.1021/acs.orglett.7b02775.
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Hole, Paul S., Lorna Pearn, Amanda J. Tonks, Philip E. James, Alan K. Burnett, Richard L. Darley i Alex Tonks. "Ras-induced reactive oxygen species promote growth factor–independent proliferation in human CD34+ hematopoietic progenitor cells". Blood 115, nr 6 (11.02.2010): 1238–46. http://dx.doi.org/10.1182/blood-2009-06-222869.
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Abstract Excessive production of reactive oxygen species (ROS) is a feature of human malignancy and is often triggered by activation of oncogenes such as activated Ras. ROS act as second messengers and can influence a variety of cellular process including growth factor responses and cell survival. We have examined the contribution of ROS production to the effects of N-RasG12D and H-RasG12V on normal human CD34+ progenitor cells. Activated Ras strongly up-regulated the production of both superoxide and hydrogen peroxide through the stimulation of NADPH oxidase (NOX) activity, without affecting the expression of endogenous antioxidants or the production of mitochondrially derived ROS. Activated Ras also promoted both the survival and the growth factor–independent proliferation of CD34+ cells. Using oxidase inhibitors and antioxidants, we found that excessive ROS production by these cells did not contribute to their enhanced survival; rather, ROS promoted their growth factor–independent proliferation. Although Ras-induced ROS production specifically activated the p38MAPK oxidative stress response, this failed to induce expression of the cell-cycle inhibitor, p16INK4A; instead, ROS promoted the expression of D cyclins. These data are the first to show that excessive ROS production in the context of oncogene activation can promote proliferative responses in normal human hematopoietic progenitor cells.
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Koval, M., S. T. Geist, E. M. Westphale, A. E. Kemendy, R. Civitelli, E. C. Beyer i T. H. Steinberg. "Transfected connexin45 alters gap junction permeability in cells expressing endogenous connexin43." Journal of Cell Biology 130, nr 4 (15.08.1995): 987–95. http://dx.doi.org/10.1083/jcb.130.4.987.
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Many cells express multiple connexins, the gap junction proteins that interconnect the cytosol of adjacent cells. Connexin43 (Cx43) channels allow intercellular transfer of Lucifer Yellow (LY, MW = 443 D), while connexin45 (Cx45) channels do not. We transfected full-length or truncated chicken Cx45 into a rat osteosarcoma cell line ROS-17/2.8, which expresses endogenous Cx43. Both forms of Cx45 were expressed at high levels and colocalized with Cx43 at plasma membrane junctions. Cells transfected with full-length Cx45 (ROS/Cx45) and cells transfected with Cx45 missing the 37 carboxyl-terminal amino acids (ROS/Cx45tr) showed 30-60% of the gap junctional conductance exhibited by ROS cells. Intercellular transfer of three negatively charged fluorescent reporter molecules was examined. In ROS cells, microinjected LY was transferred to an average of 11.2 cells/injected cell, while dye transfer between ROS/Cx45 cells was reduced to 3.9 transfer between ROS/Cx45 cells was reduced to 3.9 cells. In contrast, ROS/Cx45tr cells transferred LY to > 20 cells. Transfer of calcein (MW = 623 D) was also reduced by approximately 50% in ROS/Cx45 cells, but passage of hydroxycoumarin carboxylic acid (HCCA; MW = 206 D) was only reduced by 35% as compared to ROS cells. Thus, introduction of Cx45 altered intercellular coupling between cells expressing Cx43, most likely the result of direct interaction between Cx43 and Cx45. Transfection of Cx45tr and Cx45 had different effects in ROS cells, consistent with a role of the carboxyl-terminal domain of Cx45 in determining gap junction permeability or interactions between connexins. These data suggest that coexpression of multiple connexins may enable cells to achieve forms of intercellular communication that cannot be attained by expression of a single connexin.
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Sarniak, Agata, Joanna Lipińska, Karol Tytman i Stanisława Lipińska. "Endogenous mechanisms of reactive oxygen species (ROS) generation". Postępy Higieny i Medycyny Doświadczalnej 70 (14.11.2016): 1150–65. http://dx.doi.org/10.5604/17322693.1224259.
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HALVEY, Patrick J., Walter H. WATSON, Jason M. HANSEN, Young-Mi GO, Afshin SAMALI i Dean P. JONES. "Compartmental oxidation of thiol–disulphide redox couples during epidermal growth factor signalling". Biochemical Journal 386, nr 2 (22.02.2005): 215–19. http://dx.doi.org/10.1042/bj20041829.
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Exogenously added ROS (reactive oxygen species) cause generalized oxidation of cellular components, whereas endogenously generated ROS induced by physiological stimuli activate discrete signal transduction pathways. Compartmentation is an important aspect of such pathways, but little is known about its role in redox signalling. We measured the redox states of cytosolic and nuclear Trx1 (thioredoxin-1) and mitochondrial Trx2 (thioredoxin-2) using redox Western blot methodologies during endogenous ROS production induced by EGF (epidermal growth factor) signalling. The glutathione redox state was measured by HPLC. Results showed that only cytosolic Trx1 undergoes significant oxidation. Thus EGF signalling involves subcellular compartmental oxidation of Trx1 in the absence of a generalized cellular oxidation.
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Leuti, Alessandro, Mauro Maccarrone i Valerio Chiurchiù. "Proresolving Lipid Mediators: Endogenous Modulators of Oxidative Stress". Oxidative Medicine and Cellular Longevity 2019 (18.06.2019): 1–12. http://dx.doi.org/10.1155/2019/8107265.
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Specialized proresolving mediators (SPMs) are a novel class of endogenous lipids, derived byω-6 andω-3 essential polyunsaturated fatty acids such as arachidonic acid (AA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) that trigger and orchestrate the resolution of inflammation, which is the series of cellular and molecular events that leads to spontaneous regression of inflammatory processes and restoring of tissue homeostasis. These lipids are emerging as highly effective therapeutic agents that exert their immunoregulatory activity by activating the proresolving pathway, as reported by a consistent bulk of evidences gathered in the last two decades since their discovery. The production of reactive oxygen (ROS) and nitrogen (RNS) species by immune cells plays indeed an important role in the inflammatory mechanisms of host defence, and it is now clear that oxidative stress, viewed as an imbalance between such species and their elimination, can lead to many chronic inflammatory diseases. This review, the first of its kind, is aimed at exploring the manifold effects of SPMs on modulation of reactive species production, along with the mechanisms through which they either inhibit molecular signalling pathways that are activated by oxidative stress or induce the expression of endogenous antioxidant systems. Furthermore, the possible role of SPMs in oxidative stress-mediated chronic disorders is also summarized, suggesting not only that their anti-inflammatory and proresolving properties are strictly associated with their antioxidant role but also that these endogenous lipids might be exploited in the treatment of several pathologies in which uncontrolled production of ROS and RNS or impairment of the antioxidant machinery represents a main pathogenetic mechanism.
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Kobayashi, Daisuke, Kei Kondo, Nobuyuki Uehara, Seiko Otokozawa, Naoki Tsuji, Atsuhito Yagihashi i Naoki Watanabe. "Endogenous Reactive Oxygen Species Is an Important Mediator of Miconazole Antifungal Effect". Antimicrobial Agents and Chemotherapy 46, nr 10 (październik 2002): 3113–17. http://dx.doi.org/10.1128/aac.46.10.3113-3117.2002.
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ABSTRACT We investigated the significance of endogenous reactive oxygen species (ROS) produced by fungi treated with miconazole. ROS production in Candida albicans was measured by a real-time fluorogenic assay. The level of ROS production was increased by miconazole at the MIC (0.125 μg/ml) and was enhanced further in a dose-dependent manner, with a fourfold increase detected when miconazole was used at 12.5 μg/ml. This increase in the level of ROS production was completely inhibited by pyrrolidinedithiocarbamate (PDTC), an antioxidant, at 10 μM. In a colony formation assay, the decrease in cell viability associated with miconazole treatment was significantly prevented by addition of PDTC. Moreover, the level of ROS production by 10 clinical isolates of Candida species was inversely correlated with the miconazole MIC (r = −0.8818; P < 0.01). These results indicate that ROS production is important to the antifungal activity of miconazole.
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Wu, Jiaye, Yue Zhang, Ruizhi Hao, Yuan Cao, Xiaoyi Shan i Yanping Jing. "Nitric Oxide Enhances Cytotoxicity of Lead by Modulating the Generation of Reactive Oxygen Species and Is Involved in the Regulation of Pb2+ and Ca2+ Fluxes in Tobacco BY-2 Cells". Plants 8, nr 10 (9.10.2019): 403. http://dx.doi.org/10.3390/plants8100403.
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Lead is a heavy metal known to be toxic to both animals and plants. Nitric oxide (NO) was reported to participate in plant responses to different heavy metal stresses. In this study, we analyzed the function of exogenous and endogenous NO in Pb-induced toxicity in tobacco BY-2 cells, focusing on the role of NO in the generation of reactive oxygen species (ROS) as well as Pb2+ and Ca2+ fluxes using non-invasive micro-test technology (NMT). Pb treatment induced BY-2 cell death and rapid NO and ROS generation, while NO burst occurred earlier than ROS accumulation. The elimination of NO by 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) resulted in a decrease of ROS, and the supplementation of NO by sodium nitroprusside (SNP) caused an increased accumulation of ROS. Furthermore, the addition of exogenous NO stimulated Pb2+ influx, thus promoting Pb uptake in cells and aggravating Pb-induced toxicity in cells, whereas the removal of endogenous NO produced the opposite effect. Moreover, we also found that both exogenous and endogenous NO enhanced Pb-induced Ca2+ effluxes and calcium homeostasis disorder. These results suggest that exogenous and endogenous NO played a critical regulatory role in BY-2 cell death induced by Pb stress by promoting Pb2+ influx and accumulation and disturbing calcium homeostasis.
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Berdiaki, Aikaterini, Monica Neagu, Ioanna Spyridaki, Andrey Kuskov, Serge Perez i Dragana Nikitovic. "Hyaluronan and Reactive Oxygen Species Signaling—Novel Cues from the Matrix?" Antioxidants 12, nr 4 (28.03.2023): 824. http://dx.doi.org/10.3390/antiox12040824.
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Hyaluronan (HA) is a naturally occurring non-sulfated glycosaminoglycan (GAG) localized to the cell surface and the tissue extracellular matrix (ECM). It is composed of disaccharides containing glucuronic acid and N-acetylglucosamine, is synthesized by the HA synthase (HAS) enzymes and is degraded by hyaluronidase (HYAL) or reactive oxygen and nitrogen species (ROS/RNS) actions. HA is deposited as a high molecular weight (HMW) polymer and degraded to low molecular weight (LMW) fragments and oligosaccharides. HA affects biological functions by interacting with HA-binding proteins (hyaladherins). HMW HA is anti-inflammatory, immunosuppressive, and antiangiogenic, whereas LMW HA has pro-inflammatory, pro-angiogenetic, and oncogenic effects. ROS/RNS naturally degrade HMW HA, albeit at enhanced levels during tissue injury and inflammatory processes. Thus, the degradation of endothelial glycocalyx HA by increased ROS challenges vascular integrity and can initiate several disease progressions. Conversely, HA exerts a vital role in wound healing through ROS-mediated HA modifications, which affect the innate immune system. The normal turnover of HA protects against matrix rigidification. Insufficient turnover leads to increased tissue rigidity, leading to tissue dysfunction. Both endogenous and exogenous HMW HA have a scavenging capacity against ROS. The interactions of ROS/RNS with HA are more complex than presently perceived and present an important research topic.
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Chen, Billy T., Marat V. Avshalumov i Margaret E. Rice. "H2O2 Is a Novel, Endogenous Modulator of Synaptic Dopamine Release". Journal of Neurophysiology 85, nr 6 (1.06.2001): 2468–76. http://dx.doi.org/10.1152/jn.2001.85.6.2468.
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Recent evidence suggests that reactive oxygen species (ROS) might act as modulators of neuronal processes, including synaptic transmission. Here we report that synaptic dopamine (DA) release can be modulated by an endogenous ROS, H2O2. Electrically stimulated DA release was monitored in guinea pig striatal slices using carbon-fiber microelectrodes with fast-scan cyclic voltammetry. Exogenously applied H2O2reversibly inhibited evoked release in the presence of 1.5 mM Ca2+. The effectiveness of exogenous H2O2, however, was abolished or decreased by conditions that enhance Ca2+ entry, including increased extracellular Ca2+ concentration ([Ca2+]o; to 2.4 mM), brief, high-frequency stimulation, and blockade of inhibitory D2 autoreceptors. To test whether DA release could be modulated by endogenous H2O2, release was evoked in the presence of the H2O2-scavenging enzyme, catalase. In the presence of catalase, evoked [DA]o was 60% higher than after catalase washout, demonstrating that endogenously generated H2O2 can also inhibit DA release. Importantly, the Ca2+ dependence of the catalase-mediated effect was opposite to that of H2O2: catalase had a greater enhancing effect in 2.4 mM Ca2+ than in 1.5 mM, consistent with enhanced H2O2 generation in higher [Ca2+]o. Together these data suggest that H2O2production is Ca2+ dependent and that the inhibitory mechanism can be saturated, thus preventing further effects from exogenous H2O2. These findings show for the first time that endogenous H2O2 can modulate vesicular neurotransmitter release, thus revealing an important new signaling role for ROS in synaptic transmission.
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Fitzgerald, Phillip, Daniel Beury i Suzanne Ostrand-Rosenberg. "Glutathione S-transferases as regulators of tumor-induced myeloid-derived suppressor cell survival (66.38)". Journal of Immunology 186, nr 1_Supplement (1.04.2011): 66.38. http://dx.doi.org/10.4049/jimmunol.186.supp.66.38.
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Abstract Tumor-induced myeloid-derived suppressor cells (MDSC) are a major barrier to tumor immunotherapy because they inhibit T-cell anti-tumor immunity through various mechanisms, including cystine sequestration and production of reactive oxygen species (ROS). MDSC accumulation, suppressive potency, and survival are driven by inflammation, which also increases MDSC production of ROS. Surprisingly, ROS do not adversely affect MDSC, suggesting that MDSC neutralize endogenous ROS. Because MDSC survival is likely to be controlled by the mechanisms that protect them against endogenous ROS, we are identifying molecules that regulate ROS levels with the goal of identifying potential targets for inducing MDSC apoptosis. Glutathione (GSH) is the major antioxidant that detoxifies ROS in conjunction with various isoforms of GSH S-transferase (GST) that catalyze the detoxification process. Because of their role in detoxifying intracellular ROS, we are analyzing intracellular levels of GSH and multiple GST isoenzymes in conventional and inflammatory MDSC to understand how inflammation protects MDSC and thus promotes tumorigenesis. GST isoforms that facilitate MDSC survival will be novel drug targets for reducing tumor-induced immune suppression and facilitating tumor immunotherapy.
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Reid, Michael B. "Invited Review: Redox modulation of skeletal muscle contraction: what we know and what we don't". Journal of Applied Physiology 90, nr 2 (1.02.2001): 724–31. http://dx.doi.org/10.1152/jappl.2001.90.2.724.
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Over the past decade, reactive oxygen species (ROS) and nitric oxide (NO) derivatives have been established as physiological modulators of skeletal muscle function. This mini-review addresses the roles of these molecules as endogenous regulators of muscle contraction. The article is organized in two parts. First, established concepts are briefly outlined. This section provides an overview of ROS production by muscle, antioxidant buffers that oppose ROS effects, enzymatic synthesis of NO in muscle, the effects of endogenous ROS on contractile function, and NO as a contractile modulator. Second, a selected group of unresolved topics are highlighted. These more controversial issues include putative source(s) of regulatory ROS, the relative importance of the two NO synthase isoforms constitutively coexpressed by muscle fibers, molecular mechanisms of ROS and NO action, and the physiological relevance of redox regulation. By discussing current questions, as well as the established paradigm, this article is intended to further debate and stimulate research in this area.
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Yan, Ying, Fei Tong i Jianer Chen. "Endogenous BMP-4/ROS/COX-2 Mediated IPC and Resveratrol Alleviated Brain Damage". Current Pharmaceutical Design 25, nr 9 (9.07.2019): 1030–39. http://dx.doi.org/10.2174/1381612825666190506120611.
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The objective of the study was to examine the therapeutic role of combined ischemic preconditioning (IPC) and resveratrol (RES) on brain ischemia/reperfusion injury (BI/RI) by modulating endogenous bone morphogenetic protein-4 (BMP-4)/reactive oxygen species (ROS)/cyclooxygenase-2 (COX-2) in rats. Sprague Dawley (SD) rats were pretreated with 20 mg/kg RES (20 mg/kg RES was administered once a day via intraperitoneal injection 7 days prior to the I/R procedure) and IPC (equal volumes of saline were administered once a day by intraperitoneal injection over 7 days, and the bilateral common carotid arteries were separated for clamp 5 minutes followed by 5 minutes of reperfusion prior to the I/R procedure), and then subjected to 2 hours of ischemia and 22 hours of reperfusion. Blood and cerebral tissues were collected, cerebral pathological injuries and infarct sizes were investigated, serum interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels were measured, the activities of superoxide dismutase (SOD) and ROS were calculated, the contents of methane dicarboxylic aldehyde (MDA), IL-6, TNF-α and hemodynamic change were estimated, and expression levels of b-cell lymphoma-2 (Bcl-2), bcl-2-associated x (Bax), BMP-4 and COX-2 were assessed in cerebral tissues. IPC, RES and a combination of IPC and RES preconditioning ameliorated the pathological damage and infarct sizes, reduced cerebral oxidative stress damage, alleviated inflammatory damage, restrained apoptosis, and downregulated the expression levels of BMP-4 and COX-2 compared with those of the ischemia/reperfusion (I/R) group. This study suggested a combined strategy that could enhance protection against BI/RI in clinical brain disease.
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Xu, Jin-Wei, Chen-Chung Liao, Ke-Chang Hung, Zhong-Yao Wang, Yu-Tang Tung i Jyh-Horng Wu. "Proteomics Reveals Octyl Gallate as an Environmentally Friendly Wood Preservative Leading to Reactive Oxygen Species-Driven Metabolic Inflexibility and Growth Inhibition in White-Rot Fungi (Lenzites betulina and Trametes versicolor)". Journal of Fungi 7, nr 2 (17.02.2021): 145. http://dx.doi.org/10.3390/jof7020145.
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The most commonly applied wood preservatives are based on creosote, pentachlorophenol, and waterborne chromate copper arsenate, which negatively affect the environment. Thus, environmentally friendly wood preservatives are required. This study investigated the antifungal activity and mechanism of several long-chain alkyl gallates (3,4,5-trihydroxybenzoates) against white-rot fungi, Lenzites betulina and Trametes versicolor. The results revealed that octyl gallate (OG) had the best antifungal activity. Additionally, OG may have a mechanism of action similar to surfactants and inhibit ATPase activity, causing mitochondrial dysfunction and endogenous reactive oxygen species (ROS) production. Upon exposure to endogenous ROS, cells rapidly inhibit the synthesis of 60S ribosomal subunits, thus reducing the mycelial growth rate. L. betulina and T. versicolor also remodeled their energy metabolism in response to low ATP levels and endogenous ROS. After OG treatment, ATP citrate synthase activity was downregulated and glycolytic activity was upregulated in L. betulina. However, the activity of aerobic pathways was decreased and the oxidative branch of the pentose phosphate pathway was redirected form nicotinamide adenine dinucleotide phosphate (NADPH) to minimize endogenous ROS-mediated damage in T. versicolor. Taken together, these observations reveal that OG is a potent inhibitor of white-rot fungus. Further structural optimization research and pharmacological investigations are warranted.
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Katiyar, Sanjay, Mathew C. Casimiro, Luis Dettin, Xiaoming Ju, Erwin F. Wagner, Hirokazu Tanaka i Richard G. Pestell. "C-junInhibits Mammary Apoptosis In Vivo". Molecular Biology of the Cell 21, nr 23 (grudzień 2010): 4264–74. http://dx.doi.org/10.1091/mbc.e10-08-0705.
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c-jun, which is overexpressed in a number of human cancers encodes a critical component of the AP-1 complex. c-jun has been shown to either induce or inhibit cellular apoptosis. Germ line deletion of both c-jun alleles is embryonically lethal. To determine the role of the endogenous c-jun gene in apoptosis, we performed mammary epithelial cell–targeted somatic deletion using floxed c-jun (c-junf/f) conditional knockout mice. Laser capture microdissection demonstrated endogenous c-jun inhibits expression of apoptosis inducing genes and reactive oxygen species (ROS)-reducing genes (MnSOD, catalase). ROS have been implicated in apoptosis and undergo enzymatic elimination via MnSOD and CuZnSOD with further detoxification via catalase. c-jun–mediated survival was in part dependent on ROS production. c-jun–mediated repression of MnSOD and catalase occurred via mitochondrial complex I and NOX I. Collectively, these studies define a pivotal role of endogenous c-jun in promoting cell survival via maintaining mitochondrial integrity and expression of the key regulators of ROS production.
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Uchikura, Keiichiro, Tatehiko Wada, Sumito Hoshino, Yuichi Nagakawa, Takashi Aiko, Gregory B. Bulkley, Andrew S. Klein i Zhaoli Sun. "Lipopolysaccharides induced increases in Fas ligand expression by Kupffer cells via mechanisms dependent on reactive oxygen species". American Journal of Physiology-Gastrointestinal and Liver Physiology 287, nr 3 (wrzesień 2004): G620—G626. http://dx.doi.org/10.1152/ajpgi.00314.2003.
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Fas-Fas ligand (FasL)-dependent pathways exert a suppressive effect on inflammatory responses in immune-privileged organs. FasL expression in hepatic Kupffer cells (KC) has been implicated in hepatic immunoregulation. In this study, modulation of FasL expression of KC by endogenous gut-derived bacterial LPS and the role of reactive oxygen species (ROS) as potential mediators of FasL expression in KC were investigated. LPS stimulation of KC resulted in upstream ROS generation and, subsequently, increased FasL expression and consequent Jurkat cell (Fas-positive) apoptosis. The NADPH oxidase and xanthine oxidase enzymatic pathways appear to be major sources of this upstream ROS generation. Increased FasL expression was blocked by antioxidants and by enzymatic blocking of ROS generation. Exogenous administration of H2O2stimulated KC FasL expression and subsequent Jurkat cell apoptosis. Intracellular endogenous ROS generation may therefore represent an important signal transduction pathway for FasL expression in KC.
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Syed, Ismail, Chandrashekara N. Kyathanahalli i Anjaneyulu Kowluru. "Phagocyte-like NADPH oxidase generates ROS in INS 832/13 cells and rat islets: role of protein prenylation". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 300, nr 3 (marzec 2011): R756—R762. http://dx.doi.org/10.1152/ajpregu.00786.2010.
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Recent evidence suggests that an acute increase in the generation of phagocyte-like NADPH-oxidase (Nox)-mediated reactive oxygen species (ROS) may be necessary for glucose-stimulated insulin secretion. Using rat islets and INS 832/13 cells, we tested the hypothesis that activation of specific G proteins is necessary for nutrient-mediated intracellular generation of ROS. Stimulation of β-cells with glucose or a mixture of mitochondrial fuels (mono-methylsuccinate plus α-ketoisocaproic acid) markedly elevated intracellular accumulation of ROS, which was attenuated by selective inhibitors of Nox (e.g., apocynin or diphenyleneiodonium chloride) or short interfering RNA-mediated knockdown of p47phox, one of the subunits of Nox. Selective inhibitors of protein prenylation (FTI-277 or GGTI-2147) markedly inhibited nutrient-induced ROS generation, suggesting that activation of one (or more) prenylated small G proteins and/or γ-subunits of trimeric G proteins is involved in this signaling axis. Depletion of endogenous GTP levels with mycophenolic acid significantly reduced glucose-induced activation of Rac1 and ROS generation in these cells. Other immunosuppressants, like cyclosporine A or rapamycin, which do not deplete endogenous GTP levels, failed to affect glucose-induced ROS generation, suggesting that endogenous GTP is necessary for glucose-induced Nox activation and ROS generation. Treatment of INS 832/13 cells or rat islets with pertussis toxin (Ptx), which ADP ribosylates and inhibits inhibitory class of trimeric G proteins (i.e., Gi or Go), significantly attenuated glucose-induced ROS generation in these cells, implicating activation of a Ptx-sensitive G protein in these signaling cascade. Together, our findings suggest a prenylated Ptx-sensitive signaling step couples Rac1 activation in the signaling steps necessary for glucose-mediated generation of ROS in the pancreatic β-cells.
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Hamitouche, Fella, Jean Armengaud, Luc Dedieu i Catherine Duport. "Cysteine Proteome Reveals Response to Endogenous Oxidative Stress in Bacillus cereus". International Journal of Molecular Sciences 22, nr 14 (14.07.2021): 7550. http://dx.doi.org/10.3390/ijms22147550.
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At the end of exponential growth, aerobic bacteria have to cope with the accumulation of endogenous reactive oxygen species (ROS). One of the main targets of these ROS is cysteine residues in proteins. This study uses liquid chromatography coupled to high-resolution tandem mass spectrometry to detect significant changes in protein abundance and thiol status for cysteine-containing proteins from Bacillus cereus during aerobic exponential growth. The proteomic profiles of cultures at early-, middle-, and late-exponential growth phases reveals that (i) enrichment in proteins dedicated to fighting ROS as growth progressed, (ii) a decrease in both overall proteome cysteine content and thiol proteome redox status, and (iii) changes to the reduced thiol status of some key proteins, such as the transition state transcriptional regulator AbrB. Taken together, our data indicate that growth under oxic conditions requires increased allocation of protein resources to attenuate the negative effects of ROS. Our data also provide a strong basis to understand the response mechanisms used by B. cereus to deal with endogenous oxidative stress.
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Paladino, Simona, Andrea Conte, Rocco Caggiano, Giovanna Maria Pierantoni i Raffaella Faraonio. "Nrf2 Pathway in Age-Related Neurological Disorders: Insights into MicroRNAs". Cellular Physiology and Biochemistry 47, nr 5 (2018): 1951–76. http://dx.doi.org/10.1159/000491465.
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A general hallmark of neurological diseases is the loss of redox homeostasis that triggers oxidative damages to biomolecules compromising neuronal function. Under physiological conditions the steady-state concentrations of reactive oxygen species (ROS) and reactive nitrogen species (RNS) are finely regulated for proper cellular functions. Reduced surveillance of endogenous antioxidant defenses and/or increased ROS/RNS production leads to oxidative stress with consequent alteration of physiological processes. Neuronal cells are particularly susceptible to ROS/RNS due to their biochemical composition. Overwhelming evidences indicate that nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-linked pathways are involved in protective mechanisms against oxidative stress by regulating antioxidant and phase II detoxifying genes. As such, Nrf2 deregulation has been linked to both aging and pathogenesis of many human chronic diseases, including neurodegenerative ones such as Parkinson’s disease, Alzheimer’s disease and amyotrophic lateral sclerosis. Nrf2 activity is tightly regulated by a fine balance between positive and negative modulators. A better understanding of the regulatory mechanisms underlying Nrf2 activity could help to develop novel therapeutic interventions to prevent, slow down or possibly reverse various pathological states. To this end, microRNAs (miRs) are attractive candidates because they are linked to intracellular redox status being regulated and, post-transcriptionally, regulating key components of ROS/RNS pathways, including Nrf2.
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Shohami, Esther, Elie Beit-Yannai, Michal Horowitz i Ron Kohen. "Oxidative Stress in Closed-Head Injury: Brain Antioxidant Capacity as an Indicator of Functional Outcome". Journal of Cerebral Blood Flow & Metabolism 17, nr 10 (październik 1997): 1007–19. http://dx.doi.org/10.1097/00004647-199710000-00002.
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It has been suggested that reactive oxygen species (ROS) play a role in the pathophysiology of brain damage. A number of therapeutic approaches, based on scavenging these radicals, have been attempted both in experimental models and in the clinical setting. In an experimental rat and mouse model of closed-head injury (CHI), we have studied the total tissue nonenzymatic antioxidant capacity to combat ROS. A major mechanism for neutralizing ROS uses endogenous low-molecular weight antioxidants (LMWA). This review deals with the source and nature of ROS in the brain, along with the endogenous defense mechanisms that fight ROS. Special emphasis is placed on LMWA such as ascorbate, urate, tocopherol, lipoic acid, and histidine-related compounds. A novel electrochemical method, using cyclic voltammetry for the determination of total tissue LMWA, is described. The temporal changes in brain LMWA after CHI, as part of the response of the tissue to high ROS levels, and the correlation between the ability of the brain to elevate LMWA and clinical outcome are addressed. We relate to the beneficial effects observed in heat-acclimated rats and the detrimental effects of injury found in apolipoprotein E-deficient mice. Finally, we summarize the effects of cerebroprotective pharmacological agents including the iron chelator desferal, superoxide dismutase, a stable radical from the nitroxide family, and HU-211, a nonpsychotoropic cannabinoid with antioxidant properties. We conclude that ROS play a key role in the pathophysiology of brain injury, and that their neutralization by endogenous or exogenous antioxidants has a protective effect. It is suggested, therefore, that the brain responds to ROS by increasing LMWA, and that the degree of this response is correlated with clinical recovery. The greater the response, the more favorable the outcome.
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Laurent, Alexis, Carole Nicco, Christiane Chéreau, Claire Goulvestre, Jérôme Alexandre, Arnaud Alves, Eva Lévy i in. "Controlling Tumor Growth by Modulating Endogenous Production of Reactive Oxygen Species". Cancer Research 65, nr 3 (1.02.2005): 948–56. http://dx.doi.org/10.1158/0008-5472.948.65.3.
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Abstract Paradoxically, reactive oxygen species (ROS) can promote normal cellular proliferation and carcinogenesis, and can also induce apoptosis of tumor cells. In this report, we study the contribution of ROS to various cellular signals depending on the nature and the level of ROS produced. In nontransformed NIH 3T3 cells, ROS are at low levels and originate from NADPH oxidase. Hydrogen peroxide (H2O2), controlled by the glutathione system, is pivotal for the modulation of normal cell proliferation. In CT26 (colon) and Hepa 1-6 (liver) tumor cells, high levels of ROS, close to the threshold of cytotoxicity, are produced by mitochondria and H2O2 is controlled by catalase. N-acetylcysteine, which decreases H2O2 levels, inhibits mitogen-activated protein kinase and normal cell proliferation but increases tumor cell proliferation as H2O2 concentration drops from the toxicity threshold. In contrast, antioxidant molecules, such as mimics of superoxide dismutase (SOD), increase H2O2 levels through superoxide anion dismutation, as well as in vitro proliferation of normal cells, but kill tumor cells. CT26 tumors were implanted in mice and treated by oxaliplatin in association with one of the three SOD mimics manganese(III)tetrakis(4-benzoic acid) porphyrin, copper(II)(3,5-diisopropylsalicylate)2, or manganese dipyridoxyl diphosphate. After 1 month, the volumes of tumors were respectively 35%, 31%, and 63% smaller than with oxaliplatin alone (P < 0.001). Similar data were gained with Hepa 1-6 tumors. In conclusion, antioxidant molecules may have opposite effects on tumor growth. SOD mimics can act in synergy with cytotoxic drugs to treat colon and liver cancers.
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Berndt, Carsten, Christopher Horst Lillig i Arne Holmgren. "Thiol-based mechanisms of the thioredoxin and glutaredoxin systems: implications for diseases in the cardiovascular system". American Journal of Physiology-Heart and Circulatory Physiology 292, nr 3 (marzec 2007): H1227—H1236. http://dx.doi.org/10.1152/ajpheart.01162.2006.
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Reactive oxygen species (ROS) and the cellular thiol redox state are crucial mediators of multiple cell processes like growth, differentiation, and apoptosis. Excessive ROS production or oxidative stress is associated with several diseases, including cardiovascular disorders like ischemia-reperfusion. To prevent ROS-induced disorders, the heart is equipped with effective antioxidant systems. Key players in defense against oxidative stress are members of the thioredoxin-fold family of proteins. Of these, thioredoxins and glutaredoxins maintain a reduced intracellular redox state in mammalian cells by the reduction of protein thiols. The reversible oxidation of Cys-Gly-Pro-Cys or Cys-Pro(Ser)-Tyr-Cys active site cysteine residues is used in reversible electron transport. Thioredoxins and glutaredoxins belong to corresponding systems consisting of NADPH, thioredoxin reductase, and thioredoxin or NADPH, glutathione reductase, glutathione, and glutaredoxin, respectively. Thioredoxin as well as glutaredoxin activities appear to be very important for the progression and severity of several cardiovascular disorders. These proteins function not only as antioxidants, they inhibit or activate apoptotic signaling molecules like apoptosis signal-regulating kinase 1 and Ras or transcription factors like NF-κB. Thioredoxin activity is regulated by the endogenous inhibitor thioredoxin-binding protein 2 (TBP-2), indicating an important role of the balance between thioredoxin and TBP-2 levels in cardiovascular diseases. In this review, we will summarize cardioprotective effects of endogenous thioredoxin and glutaredoxin systems as well as the high potential in clinical applications of exogenously applied thioredoxin or glutaredoxin or the induction of endogenous thioredoxin and glutaredoxin systems.
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Tang, Chunchao, Yuqi Gao, Tingting Liu, Yuxing Lin, Xiaomeng Zhang, Chaochao Zhang, Xiang Li, Tianchao Zhang, Lupei Du i Minyong Li. "Bioluminescent probe for detecting endogenous hypochlorite in living mice". Organic & Biomolecular Chemistry 16, nr 4 (2018): 645–51. http://dx.doi.org/10.1039/c7ob02842c.
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Sharma, Anmol, Pawan Gupta i Pranav Kumar Prabhakar. "Endogenous Repair System of Oxidative Damage of DNA". Current Chemical Biology 13, nr 2 (12.07.2019): 110–19. http://dx.doi.org/10.2174/2212796813666190221152908.
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DNA is one of the most important biomolecules of living cells which carries genetic information from generation to generation. Many endogenous and exogenous agents may disrupt the structure of DNA. Change in the cellular genome can lead to errors in replication, transcription and in protein synthesis. DNA damage occurs naturally or result from a metabolic and hydrolytic process which release some very active chemical entities like free radicals, Reactive Oxygen Species (ROS), Reactive Nitrogen Intermediate (RNI), Reactive Carbonyl Species (RCS), lipid peroxidation products and alkylating agents. Superoxide radical, hydroxyl radical and hydrogen peroxide cause a significant threat to cellular integrity by damaging the DNA, lipids, proteins and other biomolecules. Oxidative stress may be explained as a disturbance in the number of free radicals and our system’s ability to neutralize these free radicals. Imbalances in the normal redox potential can also lead to toxic effects via the generation of peroxides. Oxidation of DNA bases leads to the base damage, nick in the strand and break in the strand either single or double strand. Oxidative stress can also cause modifications in normal mechanisms of cell signaling. DNA mutation can result in a number of genetic abnormalities such as cancer, heart failure, Alzheimer’s disease, and depression. Human body has special protection in the form of antioxidant molecules and enzymes against these free radicals. Generation of ROS and its neutralization must be regulated to protect cells and signalling biomolecules from the deleterious effect of oxidative stress with the involvement of antioxidant systems, enzymes, and specific proteins. DNA repair system is a complex system which helps in the identification, removal of the wrong nucleotide and repairs them and as a result, the cell will produce correct and functional protein and active enzyme.
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Stieg, David C., Yifang Wang, Ling-Zhi Liu i Bing-Hua Jiang. "ROS and miRNA Dysregulation in Ovarian Cancer Development, Angiogenesis and Therapeutic Resistance". International Journal of Molecular Sciences 23, nr 12 (16.06.2022): 6702. http://dx.doi.org/10.3390/ijms23126702.
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The diverse repertoires of cellular mechanisms that progress certain cancer types are being uncovered by recent research and leading to more effective treatment options. Ovarian cancer (OC) is among the most difficult cancers to treat. OC has limited treatment options, especially for patients diagnosed with late-stage OC. The dysregulation of miRNAs in OC plays a significant role in tumorigenesis through the alteration of a multitude of molecular processes. The development of OC can also be due to the utilization of endogenously derived reactive oxygen species (ROS) by activating signaling pathways such as PI3K/AKT and MAPK. Both miRNAs and ROS are involved in regulating OC angiogenesis through mediating multiple angiogenic factors such as hypoxia-induced factor (HIF-1) and vascular endothelial growth factor (VEGF). The NAPDH oxidase subunit NOX4 plays an important role in inducing endogenous ROS production in OC. This review will discuss several important miRNAs, NOX4, and ROS, which contribute to therapeutic resistance in OC, highlighting the effective therapeutic potential of OC through these mechanisms.
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Brynildsen, Mark P., Jonathan A. Winkler, Catherine S. Spina, I. Cody MacDonald i James J. Collins. "Potentiating antibacterial activity by predictably enhancing endogenous microbial ROS production". Nature Biotechnology 31, nr 2 (6.01.2013): 160–65. http://dx.doi.org/10.1038/nbt.2458.
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Hörandl, Elvira, i Dave Speijer. "How oxygen gave rise to eukaryotic sex". Proceedings of the Royal Society B: Biological Sciences 285, nr 1872 (7.02.2018): 20172706. http://dx.doi.org/10.1098/rspb.2017.2706.
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How did full meiotic eukaryotic sex evolve and what was the immediate advantage allowing it to develop? We propose that the crucial determinant can be found in internal reactive oxygen species (ROS) formation at the start of eukaryotic evolution approximately 2 × 10 9 years ago. The large amount of ROS coming from a bacterial endosymbiont gave rise to DNA damage and vast increases in host genome mutation rates. Eukaryogenesis and chromosome evolution represent adaptations to oxidative stress. The host, an archaeon, most probably already had repair mechanisms based on DNA pairing and recombination, and possibly some kind of primitive cell fusion mechanism. The detrimental effects of internal ROS formation on host genome integrity set the stage allowing evolution of meiotic sex from these humble beginnings. Basic meiotic mechanisms thus probably evolved in response to endogenous ROS production by the ‘pre-mitochondrion’. This alternative to mitosis is crucial under novel, ROS-producing stress situations, like extensive motility or phagotrophy in heterotrophs and endosymbiontic photosynthesis in autotrophs. In multicellular eukaryotes with a germline–soma differentiation, meiotic sex with diploid–haploid cycles improved efficient purging of deleterious mutations. Constant pressure of endogenous ROS explains the ubiquitous maintenance of meiotic sex in practically all eukaryotic kingdoms. Here, we discuss the relevant observations underpinning this model.
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Feinendegen, L. E. "Reactive oxygen species in cell responses to toxic agents". Human & Experimental Toxicology 21, nr 2 (luty 2002): 85–90. http://dx.doi.org/10.1191/0960327102ht216oa.
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This review first summarizes experimental data on biological effects of different concentrations of ROS in mammalian cells and on their potential role in modifying cell responses to toxic agents. It then attempts to link the role of steadily produced metabolic ROS at various concentrations in mammalian cells to that of environmentally derived ROS bursts from exposure to ionizing radiation. The ROS from both sources are known to both cause biological damage and change cellular signaling, depending on their concentration at a given time. At low concentrations signaling effects of ROS appear to protect cellular survival and dominate over damage, and the reverse occurs at high ROS concentrations. Background radiation generates suprabasal ROS bursts along charged particle tracks several times a year in each nanogram of tissue, i.e., average mass of a mammalian cell. For instance, a burst of about 200 ROS occurs within less than a microsecond from low-LET irradiation such as X-rays along the track of a Compton electron (about 6 keV, ranging about 1 μm). One such track per nanogram tissue gives about 1 mGy to this mass. The number of instantaneous ROS per burst along the track of a 4-meV ¬-particle in 1 ng tissue reaches some 70000. The sizes, types and sites of these bursts, and the time intervals between them directly in and around cells appear essential for understanding low-dose and low dose-rate effects on top of effects from endogenous ROS. At background and low-dose radiation exposure, a major role of ROS bursts along particle tracks focuses on ROS-induced apoptosis of damage-carrying cells, and also on prevention and removal of DNA damage from endogenous sources by way of temporarily protective, i.e., adaptive, cellular responses. A conclusion is to consider low-dose radiation exposure as a provider of physiological mechanisms for tissue homoeostasis.
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Garlid, Anders O., Martin Jaburek, Jeremy P. Jacobs i Keith D. Garlid. "Mitochondrial reactive oxygen species: which ROS signals cardioprotection?" American Journal of Physiology-Heart and Circulatory Physiology 305, nr 7 (1.10.2013): H960—H968. http://dx.doi.org/10.1152/ajpheart.00858.2012.
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Mitochondria are the major effectors of cardioprotection by procedures that open the mitochondrial ATP-sensitive potassium channel (mitoKATP), including ischemic and pharmacological preconditioning. MitoKATP opening leads to increased reactive oxygen species (ROS), which then activate a mitoKATP-associated PKCε, which phosphorylates mitoKATP and leaves it in a persistent open state (Costa AD, Garlid KD. Am J Physiol Heart Circ Physiol 295, H874–H882, 2008). The ROS responsible for this effect is not known. The present study focuses on superoxide (O2·−), hydrogen peroxide (H2O2), and hydroxyl radical (HO˙), each of which has been proposed as the signaling ROS. Feedback activation of mitoKATP provides an ideal setting for studying endogenous ROS signaling. Respiring rat heart mitochondria were preincubated with ATP and diazoxide, together with an agent being tested for interference with this process, either by scavenging ROS or by blocking ROS transformations. The mitochondria were then assayed to determine whether or not the persistent phosphorylated open state was achieved. Dimethylsulfoxide (DMSO), dimethylformamide (DMF), deferoxamine, Trolox, and bromoenol lactone each interfered with formation of the ROS-dependent open state. Catalase did not interfere with this step. We also found that DMF blocked cardioprotection by both ischemic preconditioning and diazoxide. The lack of a catalase effect and the inhibitory effects of agents acting downstream of HO˙ excludes H2O2 as the endogenous signaling ROS. Taken together, the results support the conclusion that the ROS message is carried by a downstream product of HO˙ and that it is probably a product of phospholipid oxidation.
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Tam, Beatrice M., Orson L. Moritz, Lawrence B. Hurd i David S. Papermaster. "Identification of an Outer Segment Targeting Signal in the Cooh Terminus of Rhodopsin Using Transgenic Xenopus laevis". Journal of Cell Biology 151, nr 7 (25.12.2000): 1369–80. http://dx.doi.org/10.1083/jcb.151.7.1369.
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Mislocalization of the photopigment rhodopsin may be involved in the pathology of certain inherited retinal degenerative diseases. Here, we have elucidated rhodopsin's targeting signal which is responsible for its polarized distribution to the rod outer segment (ROS). Various green fluorescent protein (GFP)/rhodopsin COOH-terminal fusion proteins were expressed specifically in the major red rod photoreceptors of transgenic Xenopus laevis under the control of the Xenopus opsin promoter. The fusion proteins were targeted to membranes via lipid modifications (palmitoylation and myristoylation) as opposed to membrane spanning domains. Membrane association was found to be necessary but not sufficient for efficient ROS localization. A GFP fusion protein containing only the cytoplasmic COOH-terminal 44 amino acids of Xenopus rhodopsin localized exclusively to ROS membranes. Chimeras between rhodopsin and α adrenergic receptor COOH-terminal sequences further refined rhodopsin's ROS localization signal to its distal eight amino acids. Mutations/deletions of this region resulted in partial delocalization of the fusion proteins to rod inner segment (RIS) membranes. The targeting and transport of endogenous wild-type rhodopsin was unaffected by the presence of mislocalized GFP fusion proteins.
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Jimenez-Moreno, Natalia, i Jon D. Lane. "Autophagy and Redox Homeostasis in Parkinson’s: A Crucial Balancing Act". Oxidative Medicine and Cellular Longevity 2020 (10.11.2020): 1–38. http://dx.doi.org/10.1155/2020/8865611.
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Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated primarily from endogenous biochemical reactions in mitochondria, endoplasmic reticulum (ER), and peroxisomes. Typically, ROS/RNS correlate with oxidative damage and cell death; however, free radicals are also crucial for normal cellular functions, including supporting neuronal homeostasis. ROS/RNS levels influence and are influenced by antioxidant systems, including the catabolic autophagy pathways. Autophagy is an intracellular lysosomal degradation process by which invasive, damaged, or redundant cytoplasmic components, including microorganisms and defunct organelles, are removed to maintain cellular homeostasis. This process is particularly important in neurons that are required to cope with prolonged and sustained operational stress. Consequently, autophagy is a primary line of protection against neurodegenerative diseases. Parkinson’s is caused by the loss of midbrain dopaminergic neurons (mDANs), resulting in progressive disruption of the nigrostriatal pathway, leading to motor, behavioural, and cognitive impairments. Mitochondrial dysfunction, with associated increases in oxidative stress, and declining proteostasis control, are key contributors during mDAN demise in Parkinson’s. In this review, we analyse the crosstalk between autophagy and redoxtasis, including the molecular mechanisms involved and the detrimental effect of an imbalance in the pathogenesis of Parkinson’s.
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Sallmyr, Annahita, Jinshui Fan, Kamal Datta, Kyu-Tae Kim, Dan Grosu, Paul Shapiro, Donald Small i Feyruz Rassool. "Internal tandem duplication of FLT3 (FLT3/ITD) induces increased ROS production, DNA damage, and misrepair: implications for poor prognosis in AML". Blood 111, nr 6 (15.03.2008): 3173–82. http://dx.doi.org/10.1182/blood-2007-05-092510.
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Abstract Activating mutations of the FMS-like tyrosine kinase-3 (FLT3) receptor occur in approximately 30% of acute myeloid leukemia (AML) patients and, at least for internal tandem duplication (ITD) mutations, are associated with poor prognosis. FLT3 mutations trigger downstream signaling pathways including RAS-MAP/AKT kinases and signal transducer and activator of transcription-5 (STAT5). We find that FLT3/ITD mutations start a cycle of genomic instability whereby increased reactive oxygen species (ROS) production leads to increased DNA double-strand breaks (DSBs) and repair errors that may explain aggressive AML in FLT3/ITD patients. Cell lines transfected with FLT3/ITD and FLT3/ITD-positive AML cell lines and primary cells demonstrate increased ROS. Increased ROS levels appear to be produced via STAT5 signaling and activation of RAC1, an essential component of ROS-producing NADPH oxidases. A direct association of RAC1-GTP binding to phosphorylated STAT5 (pSTAT5) provides a possible mechanism for ROS generation. A FLT3 inhibitor blocked increased ROS in FLT3/ITD cells resulting in decreased DSB and increased repair efficiency and fidelity. Our study suggests that the aggressiveness of the disease and poor prognosis of AML patients with FLT3/ITD mutations could be the result of increased genomic instability that is driven by higher endogenous ROS, increased DNA damage, and decreased end-joining fidelity.
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Korge, Paavo, i James N. Weiss. "Redox regulation of endogenous substrate oxidation by cardiac mitochondria". American Journal of Physiology-Heart and Circulatory Physiology 291, nr 3 (wrzesień 2006): H1436—H1445. http://dx.doi.org/10.1152/ajpheart.01292.2005.
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Reactive oxygen species (ROS) play important roles in regulating mitochondrial function, as well as in ischemia-reperfusion injury and cardioprotection. Here we show that, in the absence of exogenous substrates, cardiac mitochondria have a surprisingly large capacity to phosphorylate ADP by oxidizing endogenous substrates, provided that H2O2 is removed from the extramitochondrial environment and a reduced environment is maintained in the matrix. In isolated mitochondria without exogenous substrates, addition of catalase and the membrane-permeant reducing agent N-acetylcysteine (Nac) or the ROS scavenger mercaptopropionyl glycine significantly increased the ability to phosphorylate added ADP, as demonstrated by 1) full recovery of membrane potential (Δψ) and matrix volume from ADP-induced dissipation and shrinkage, 2) ADP-dependent increase in O2 consumption, and 3) enhanced rate of ATP synthesis. Removal of extramitochondrial H2O2 by catalase was required to stimulate endogenous substrate oxidation, as shown by the increase in O2 consumption and Δψ. This effect was greatly enhanced by addition of Nac or mercaptopropionyl glycine to suppress oxidation-induced ROS increases in the matrix. Theoretical considerations, as well as reversible inhibition of O2 consumption with 3-mercaptopropionic acid and pyruvate in state 3, indicate that these substrates are fatty acids. Under in vivo conditions in which powerful antioxidant conditions are maintained, this mechanism may be important in stimulation of β-oxidation and ATP production at low levels of extramitochondrial fatty acids. Incapacitation of this mechanism may potentially contribute to mitochondrial dysfunction during oxidative stress.
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Das, Laxmidhar, i Manjula Vinayak. "Anti-carcinogenic action of curcumin by activation of antioxidant defence system and inhibition of NF-κB signalling in lymphoma-bearing mice". Bioscience Reports 32, nr 2 (21.11.2011): 161–70. http://dx.doi.org/10.1042/bsr20110043.
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NF-κB (nuclear factor κB) plays a significant role in inflammation, immunity, cell proliferation, apoptosis and malignancy. ROS (reactive oxygen species) are among the most important regulating factors of NF-κB. Intracellular ROS are mainly regulated by an endogenous antioxidant defence system. Any disruption of redox balance leads to oxidative stress, which causes a number of pathological conditions including inflammation and malignancy. Increased metabolic activity in cancerous cells leads to oxidative stress, which is further enhanced due to depletion of the endogenous antioxidant defence system. However, the activation and signalling of NF-κB are reported to be inhibited by overexpression and induced activity of antioxidant enzymes. Therefore the present study focuses on the correlation between the endogenous antioxidant defence system, ROS and NF-κB activation during lymphoma growth in mice. The study highlights the anti-carcinogenic role of curcumin by modulation of NF-κB activation and oxidative stress via the endogenous antioxidant defence system. Oxidative stress was monitored by lipid peroxidation, protein carbonylation and antioxidant enzyme activity. NF-κB-mediated signalling was tested by DNA-binding activity. The results reflect that intracellular production of H2O2 in oxidative tumour micro-environment regulates NF-κB activation. Curcumin inhibits oxidative state in the liver of lymphoma-bearing mice by enhancing the transcription and activities of antioxidant enzymes, which in turn modulate activation of NF-κB, leading to a decrease in lymphoma growth. Morphological changes as well as cell proliferation and cell survival assays confirmed reduced lymphoma growth. Thus curcumin contributes to cancer prevention by disrupting the vicious cycle of constant ROS production, responsible for a high oxidative micro-environment for tumour growth.
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Aranda-Rivera, Ana Karina, Alfredo Cruz-Gregorio, Yalith Lyzet Arancibia-Hernández, Estefani Yaquelin Hernández-Cruz i José Pedraza-Chaverri. "RONS and Oxidative Stress: An Overview of Basic Concepts". Oxygen 2, nr 4 (10.10.2022): 437–78. http://dx.doi.org/10.3390/oxygen2040030.
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Oxidative stress (OS) has greatly interested the research community in understanding damaging processes occurring in cells. OS is triggered by an imbalance between reactive oxygen species (ROS) production and their elimination by the antioxidant system; however, ROS function as second messengers under physiological conditions. ROS are produced from endogenous and exogenous sources. Endogenous sources involve mitochondria, nicotinamide adenine dinucleotide phosphate hydrogen (NADPH), oxidases (NOXs), endoplasmic reticulum (ER), xanthine oxidases (XO), endothelial nitric oxide synthase (eNOs), and others. In contrast, exogenous ROS might be generated through ultraviolet (UV) light, ionizing radiation (IR), contaminants, and heavy metals, among others. It can damage DNA, lipids, and proteins if OS is not controlled. To avoid oxidative damage, antioxidant systems are activated. In the present review, we focus on the basic concepts of OS, highlighting the production of reactive oxygen and nitrogen species (RONS) derived from internal and external sources and the last elimination. Moreover, we include the cellular antioxidant system regulation and their ability to decrease OS. External antioxidants are also proposed as alternatives to ameliorate OS. Finally, we review diseases involving OS and their mechanisms.
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Airik, Merlin, Haley Arbore, Elizabeth Childs, Amy B. Huynh, Yu Leng Phua, Chi Wei Chen, Katherine Aird i in. "Mitochondrial ROS Triggers KIN Pathogenesis in FAN1-Deficient Kidneys". Antioxidants 12, nr 4 (8.04.2023): 900. http://dx.doi.org/10.3390/antiox12040900.
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Karyomegalic interstitial nephritis (KIN) is a genetic adult-onset chronic kidney disease (CKD) characterized by genomic instability and mitotic abnormalities in the tubular epithelial cells. KIN is caused by recessive mutations in the FAN1 DNA repair enzyme. However, the endogenous source of DNA damage in FAN1/KIN kidneys has not been identified. Here we show, using FAN1-deficient human renal tubular epithelial cells (hRTECs) and FAN1-null mice as a model of KIN, that FAN1 kidney pathophysiology is triggered by hypersensitivity to endogenous reactive oxygen species (ROS), which cause chronic oxidative and double-strand DNA damage in the kidney tubular epithelial cells, accompanied by an intrinsic failure to repair DNA damage. Furthermore, persistent oxidative stress in FAN1-deficient RTECs and FAN1 kidneys caused mitochondrial deficiencies in oxidative phosphorylation and fatty acid oxidation. The administration of subclinical, low-dose cisplatin increased oxidative stress and aggravated mitochondrial dysfunction in FAN1-deficient kidneys, thereby exacerbating KIN pathophysiology. In contrast, treatment of FAN1 mice with a mitochondria-targeted ROS scavenger, JP4-039, attenuated oxidative stress and accumulation of DNA damage, mitigated tubular injury, and preserved kidney function in cisplatin-treated FAN1-null mice, demonstrating that endogenous oxygen stress is an important source of DNA damage in FAN1-deficient kidneys and a driver of KIN pathogenesis. Our findings indicate that therapeutic modulation of kidney oxidative stress may be a promising avenue to mitigate FAN1/KIN kidney pathophysiology and disease progression in patients.
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Parfenova, Helena, Charles W. Leffler, Shyamali Basuroy, Jianxiong Liu i Alexander L. Fedinec. "Antioxidant Roles of Heme Oxygenase, Carbon Monoxide, and Bilirubin in Cerebral Circulation during Seizures". Journal of Cerebral Blood Flow & Metabolism 32, nr 6 (22.02.2012): 1024–34. http://dx.doi.org/10.1038/jcbfm.2012.13.
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Postictal cerebrovascular dysfunction is an adverse effect of seizures in newborn piglets. The brain heme oxygenase (HO) provides protection against cerebrovascular dysfunction. We investigated the contribution of reactive oxygen species (ROS) to seizure-induced vascular damage and the mechanism of HO vasoprotection. In a bicuculline model of seizures, we addressed the hypotheses: (1) seizures increase brain ROS; (2) ROS contribute to cerebral vascular dysfunction; (3) ROS initiate a vasoprotective mechanisms by activating endogenous HO; and (4) HO products have antioxidant properties. As assessed by dihydroethidium oxidation (ox-DHE), seizures increased ROS in cerebral vessels and cortical astrocytes; ox-DHE elevation was prevented by tiron and apocynin. An HO inhibitor, tin protoporphyrin, potentiated, whereas an HO-1 inducer, cobalt protoporphyrin, blocked seizure-induced increase in DHE oxidation. Heme oxygenase products carbon monoxide (CO) (CORM-A1) and bilirubin attenuated ox-DHE elevation during seizures. Antioxidants tiron and bilirubin prevented the loss of postictal cerebrovascular dilations to bradykinin, glutamate, and sodium nitroprusside. Tiron and apocynin abrogated activation of the brain HO during seizures. Overall, these data suggest that long-term adverse cerebrovascular effects of seizures are attributed to oxidative stress. On the other hand, seizure-induced ROS are required for activation of the endogenous antioxidant HO/CO/bilirubin system that alleviates oxidative stress-induced loss of postictal cerebrovascular function in piglets.
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ZOELLER, Raphael A., Andrew C. LAKE, Narasimhan NAGAN, Daniel P. GAPOSCHKIN, Margaret A. LEGNER i Wilfred LIEBERTHAL. "Plasmalogens as endogenous antioxidants: somatic cell mutants reveal the importance of the vinyl ether". Biochemical Journal 338, nr 3 (8.03.1999): 769–76. http://dx.doi.org/10.1042/bj3380769.
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Exposure of plasmalogen-deficient variants of the murine cell line RAW 264.7 to short-term (0–100 min) treatment with electron transport inhibitors antimycin A or cyanide (chemical hypoxia) resulted in a more rapid loss of viability than in the parent strain. Results suggested that plasmalogen-deficient cells were more sensitive to reactive oxygen species (ROS) generated during chemical hypoxia; the mutants could be rescued from chemical hypoxia by using the antioxidant Trolox, an α-tocopherol analogue, and they were more sensitive to ROS generation by plumbagin or by rose bengal treatment coupled with irradiation. In addition, the use of buffers containing 2H2O greatly enhanced the cytotoxic effect of chemical hypoxia, suggesting the involvement of singlet oxygen. We used the unique enzymic deficiencies displayed by the mutants to differentially restore either plasmenylethanolamine (the major plasmalogen species normally found in this cell line) or its biosynthetic precursor, plasmanylethanolamine. Restoration of plasmenylethanolamine, which contains the vinyl ether, resulted in wild-type-like resistance to chemical hypoxia and ROS generators, whereas increasing levels of its precursor, which bears the saturated ether, had no effect on cell survival. These findings identify the vinyl ether double bond as a crucial element in cellular protection under these conditions and support the hypothesis that plasmalogens, through the vinyl ether, act as antioxidants to protect cells against ROS. These phospholipids might protect cells from ROS-mediated damage during events such as chemical hypoxia.
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Arazi, Hamid, Ehsan Eghbali i Katsuhiko Suzuki. "Creatine Supplementation, Physical Exercise and Oxidative Stress Markers: A Review of the Mechanisms and Effectiveness". Nutrients 13, nr 3 (6.03.2021): 869. http://dx.doi.org/10.3390/nu13030869.
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Oxidative stress is the result of an imbalance between the generation of reactive oxygen species (ROS) and their elimination by antioxidant mechanisms. ROS degrade biogenic substances such as deoxyribonucleic acid, lipids, and proteins, which in turn may lead to oxidative tissue damage. One of the physiological conditions currently associated with enhanced oxidative stress is exercise. Although a period of intense training may cause oxidative damage to muscle fibers, regular exercise helps increase the cells’ ability to reduce the ROS over-accumulation. Regular moderate-intensity exercise has been shown to increase antioxidant defense. Endogenous antioxidants cannot completely prevent oxidative damage under the physiological and pathological conditions (intense exercise and exercise at altitude). These conditions may disturb the endogenous antioxidant balance and increase oxidative stress. In this case, the use of antioxidant supplements such as creatine can have positive effects on the antioxidant system. Creatine is made up of two essential amino acids, arginine and methionine, and one non-essential amino acid, glycine. The exact action mechanism of creatine as an antioxidant is not known. However, it has been shown to increase the activity of antioxidant enzymes and the capability to eliminate ROS and reactive nitrogen species (RNS). It seems that the antioxidant effects of creatine may be due to various mechanisms such as its indirect (i.e., increased or normalized cell energy status) and direct (i.e., maintaining mitochondrial integrity) mechanisms. Creatine supplement consumption may have a synergistic effect with training, but the intensity and duration of training can play an important role in the antioxidant activity. In this study, the researchers attempted to review the literature on the effects of creatine supplementation and physical exercise on oxidative stress.
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Castelli, Serena, Pamela De Falco, Fabio Ciccarone, Enrico Desideri i Maria Rosa Ciriolo. "Lipid Catabolism and ROS in Cancer: A Bidirectional Liaison". Cancers 13, nr 21 (31.10.2021): 5484. http://dx.doi.org/10.3390/cancers13215484.
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Although cancer cell metabolism was mainly considered to rely on glycolysis, with the concomitant impairment of mitochondrial metabolism, it has recently been demonstrated that several tumor types are sustained by oxidative phosphorylation (OXPHOS). In this context, endogenous fatty acids (FAs) deriving from lipolysis or lipophagy are oxidised into the mitochondrion, and are used as a source of energy through OXPHOS. Because the electron transport chain is the main source of ROS, cancer cells relying on fatty acid oxidation (FAO) need to be equipped with antioxidant systems that maintain the ROS levels under the death threshold. In those conditions, ROS can act as second messengers, favouring proliferation and survival. Herein, we highlight the different responses that tumor cells adopt when lipid catabolism is augmented, taking into account the different ROS fates. Many papers have demonstrated that the pro- or anti-tumoral roles of endogenous FA usage are hugely dependent on the tumor type, and on the capacity of cancer cells to maintain redox homeostasis. In light of this, clinical studies have taken advantage of the boosting of lipid catabolism to increase the efficacy of tumor therapy, whereas, in other contexts, antioxidant compounds are useful to reduce the pro-survival effects of ROS deriving from FAO.
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Sadanandan, Nadia, Blaise Cozene, You Jeong Park, Jeffrey Farooq, Chase Kingsbury, Zhen-Jie Wang, Alexa Moscatello i in. "Pituitary Adenylate Cyclase-Activating Polypeptide: A Potent Therapeutic Agent in Oxidative Stress". Antioxidants 10, nr 3 (26.02.2021): 354. http://dx.doi.org/10.3390/antiox10030354.
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Stroke is a life-threatening condition that is characterized by secondary cell death processes that occur after the initial disruption of blood flow to the brain. The inability of endogenous repair mechanisms to sufficiently support functional recovery in stroke patients and the inadequate treatment options available are cause for concern. The pathology behind oxidative stress in stroke is of particular interest due to its detrimental effects on the brain. The oxidative stress caused by ischemic stroke overwhelms the neutralization capacity of the body’s endogenous antioxidant system, which leads to an overproduction of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and eventually results in cell death. The overproduction of ROS compromises the functional and structural integrity of brain tissue. Therefore, it is essential to investigate the mechanisms involved in oxidative stress to help obtain adequate treatment options for stroke. Here, we focus on the latest preclinical research that details the mechanisms behind secondary cell death processes that cause many central nervous system (CNS) disorders, as well as research that relates to how the neuroprotective molecular mechanisms of pituitary adenylate cyclase-activating polypeptides (PACAPs) could make these molecules an ideal candidate for the treatment of stroke.
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Antognazza, Maria Rosa, Ilaria Abdel Aziz i Francesco Lodola. "Use of Exogenous and Endogenous Photomediators as Efficient ROS Modulation Tools: Results and Perspectives for Therapeutic Purposes". Oxidative Medicine and Cellular Longevity 2019 (31.03.2019): 1–14. http://dx.doi.org/10.1155/2019/2867516.
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Reactive Oxygen Species (ROS) play an essential dual role in living systems. Healthy levels of ROS modulate several signaling pathways, but at the same time, when they exceed normal physiological amounts, they work in the opposite direction, playing pivotal functions in the pathophysiology of multiple severe medical conditions (i.e., cancer, diabetes, neurodegenerative and cardiovascular diseases, and aging). Therefore, the research for methods to detect their levels via light-sensitive fluorescent probes has been extensively studied over the years. However, this is not the only link between light and ROS. In fact, the modulation of ROS mediated by light has been exploited already for a long time. In this review, we report the state of the art, as well as recent developments, in the field of photostimulation of oxidative stress, from photobiomodulation (PBM) mediated by naturally expressed light-sensitive proteins to the most recent optogenetic approaches, and finally, we describe the main methods of exogenous stimulation, in particular highlighting the new insights based on optically driven ROS modulation mediated by polymeric materials.
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Oliveira, Barbara F., José Augusto Nogueira-Machado i Míriam M. Chaves. "The Role of Oxidative Stress in the Aging Process". Scientific World JOURNAL 10 (2010): 1121–28. http://dx.doi.org/10.1100/tsw.2010.94.
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The aging of organisms is characterized by a gradual functional decline of all organ systems. An appropriate theory must explain four main characteristics of aging: it is progressive, endogenous, irreversible, and deleterious for the individual. The aging of the immune system, or immunosenescence, is manifested by an increased susceptibility to infections with increased morbidity and mortality. Phagocytic capacity, synthesis of reactive oxygen intermediaries, and the intracellular killing efficiency of neutrophils are impaired in the elderly. Among all aging theories, the most updated one describes the free radicals. It implies that progressive aging is associated with higher levels of oxidative biomolecules reacted with free radicals. Although reactive oxygen species (ROS) are predominantly implicated in causing cell damage, they also play a major physiological role in several aspects of intracellular signaling and regulation. ROS include a number of chemically reactive molecules derived from oxygen. Not only oxygen, but also nitrogen can be deleterious species. The overproduction of reactive nitrogen species (RNS) is called nitrosative stress. ROS/RNS are known to play a dual role in biological systems since they can be either harmful or beneficial to living systems.
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Zhao, Fan, Jiayu Yao, Yu Tong, Dan Su, Qing Xu, Yao Ying, Wangchang Li i in. "H2O2-replenishable and GSH-depletive ROS ‘bomb’ for self-enhanced chemodynamic therapy". Materials Advances 3, nr 2 (2022): 1191–99. http://dx.doi.org/10.1039/d1ma00646k.
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Raza, Muhammad Asim, Malka Samra Malik, Muhammad Azam i Muhammad Azam. "Impact of Natural Antioxidants on Biological Systems". Lahore Garrison University Journal of Life Sciences 4, nr 02 (15.07.2020): 139–62. http://dx.doi.org/10.54692/lgujls.2019.0402105.
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ABSTRACT:Free radicals are the unstable electron-deficient species that reacts with different molecules to gain stability and to eliminate their unpaired condition. Antioxidant molecules neutralizes the free radicals by donating their electrons and inhibits the unwanted oxidative reactions in biological system. The imbalance between antioxidants and free radicals generated oxidative stress which leads to severe impairment of the biological systems. The purpose of the present review is to highlight the beneficial role of naturally occurring antioxidant systems in minimizing the damage and maintaining the homeostasis in the biological system. Enzymatic and non-enzymatic antioxidants are the major classes of natural antioxidants which executes diverse functions in the biological system to provide defense against the destructive accumulating effects of ROS/RNS. Superoxide dismutase (SOD) are responsible for providing first line of defense to thebiological system, by converting the superoxide anion radical (O oˉ) into hydrogen 2 peroxide (H O ) which eventually converted into water and oxygen. Non-enzymatic 2 2 antioxidants either endogenous or exogenous provides numerous crucial mechanisms to quench the ROS/RNS in the biological system. Endogenous antioxidants inhibits lipid peroxidation in the cellular membranes while the exogenous antioxidants acts as chain breakers and terminates the oxidative chain reaction. It is significant to sustain the level of exogenous antioxidants in the body through diet so that the normal biological processes can be maintained at optimal levels.
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Chand, Preeti, Surinder Pal Singh i Tulika Prasad. "Effect of Antioxidant on ROS Mediated Antifungal Action of ZnO Quantum Dots in Candida albicans". ECS Transactions 107, nr 1 (24.04.2022): 6621–30. http://dx.doi.org/10.1149/10701.6621ecst.
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Nanomaterials are increasingly used as new paradigm for treating infectious diseases, wherein redox perturbation using quantum dots (QDs) show tremendous potential in eliminating various multi-drug resistant microbial pathogens. Herein, spherical, monodispersed ZnO QDs of ~5-6 nm size was synthesized. These ZnO QDs significantly inhibited growth of C. albicans cells. The antifungal action of ZnO QDs against C. albicans involved oxidative stress, mediated via augmentation of endogenous reactive oxygen species (ROS). Further, endogenous ROS production by ZnO QDs and their effect on fungal cell killing was investigated in the presence of antioxidant, ascorbic acid. Results showed that antioxidant failed to offer complete protection against ZnO QDs mediated oxidative stress. It is speculated that intracellular ROS alone is not the only mechanism responsible for ZnO QDs mediated microbial toxicity and other mechanisms probably act either in coordinated or parallel manner to induce cell killing, which merit further investigations for medical adoption of ZnO QDs in biomedicine.
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Zuluaga, M., A. Barzegari, D. Letourneur, V. Gueguen i G. Pavon-Djavid. "Oxidative Stress Regulation on Endothelial Cells by Hydrophilic Astaxanthin Complex: Chemical, Biological, and Molecular Antioxidant Activity Evaluation". Oxidative Medicine and Cellular Longevity 2017 (2017): 1–15. http://dx.doi.org/10.1155/2017/8073798.
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An imbalance in the reactive oxygen species (ROS) homeostasis is involved in the pathogenesis of oxidative stress-related diseases. Astaxanthin, a xanthophyll carotenoid with high antioxidant capacities, has been shown to prevent the first stages of oxidative stress. Here, we evaluate the antioxidant capacities of astaxanthin included within hydroxypropyl-beta-cyclodextrin (CD-A) to directly and indirectly reduce the induced ROS production. First, chemical methods were used to corroborate the preservation of astaxanthin antioxidant abilities after inclusion. Next, antioxidant scavenging properties of CD-A to inhibit the cellular and mitochondrial ROS by reducing the disturbance in the redox state of the cell and the infiltration of lipid peroxidation radicals were evaluated. Finally, the activation of endogenous antioxidant PTEN/AKT, Nrf2/HO-1, and NQOI gene and protein expression supported the protective effect of CD-A complex on human endothelial cells under stress conditions. Moreover, a nontoxic effect on HUVEC was registered after CD-A complex supplementation. The results reported here illustrate the need to continue exploring the interesting properties of this hydrophilic antioxidant complex to assist endogenous systems to counteract the ROS impact on the induction of cellular oxidative stress state.