scholarly journals Plasmonic Hot-Electron Reactive Oxygen Species Generation: Fundamentals for Redox Biology

2020 ◽  
Vol 8 ◽  
Author(s):  
Elisa Carrasco ◽  
Juan Carlos Stockert ◽  
Ángeles Juarranz ◽  
Alfonso Blázquez-Castro
Keyword(s):  
Reactive Oxygen Species ◽  
Near Infrared ◽  
Chemical Reactivity ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Ros Generation ◽  
Oxygen Species ◽  
Hot Electron ◽  
Redox Biology

For decades, the possibility to generate Reactive Oxygen Species (ROS) in biological systems through the use of light was mainly restricted to the photodynamic effect: the photoexcitation of molecules which then engage in charge- or energy-transfer to molecular oxygen (O2) to initiate ROS production. However, the classical photodynamic approach presents drawbacks, like per se chemical reactivity of the photosensitizing agent or fast molecular photobleaching due to in situ ROS generation, to name a few. Recently, a new approach, which promises many advantages, has entered the scene: plasmon-driven hot-electron chemistry. The effect takes advantage of the photoexcitation of plasmonic resonances in metal nanoparticles to induce a new cohort of photochemical and redox reactions. These metal photo-transducers are considered chemically inert and can undergo billions of photoexcitation rounds without bleaching or suffering significant oxidative alterations. Also, their optimal absorption band can be shape- and size-tailored in order to match any of the near infrared (NIR) biological windows, where undesired absorption/scattering are minimal. In this mini review, the basic mechanisms and principal benefits of this light-driven approach to generate ROS will be discussed. Additionally, some significant experiments in vitro and in vivo will be presented, and tentative new avenues for further research will be advanced.

scholarly journals A Novel Tetrapeptide Derivative Exhibits In Vitro Inhibition of Neutrophil-Derived Reactive Oxygen Species and Lysosomal Enzymes Release

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Sumitra Miriyala ◽  
Manikandan Panchatcharam ◽  
Meera Ramanujam ◽  
Rengarajulu Puvanakrishnan
Keyword(s):  
Reactive Oxygen Species ◽  
Superoxide Anion ◽  
Lysosomal Enzymes ◽  
Reactive Oxygen ◽  
Peptide Sequence ◽  
Ros Generation ◽  
Oxygen Species ◽  
Complement Factors

Neutrophil infiltration plays a major role in the pathogenesis of myocardial injury. Oxidative injury is suggested to be a central mechanism of the cellular damage after acute myocardial infarction. This study is pertained to the prognostic role of a tetrapeptide derivative PEP1261 (BOC-Lys(BOC)-Arg-Asp-Ser(tBu)-OtBU), a peptide sequence (39–42) of lactoferrin, studied in the modulation of neutrophil functions in vitro by measuring the reactive oxygen species (ROS) generation, lysosomal enzymes release, and enhanced expression of C proteins. The groundwork experimentation was concerned with the isolation of neutrophils from the normal and acute myocardial infarct rats to find out the efficacy of PEP1261 in the presence of a powerful neutrophil stimulant, phorbol 12-myristate 13 acetate (PMA). Stimulation of neutrophils with PMA resulted in an oxidative burst of superoxide anion and enhanced release of lysosomal enzymes and expression of complement proteins. The present study further demonstrated that the free radicals increase the complement factors in the neutrophils confirming the role of ROS. PEP1261 treatment significantly reduced the levels of superoxide anion and inhibited the release of lysosomal enzymes in the stimulated control and infarct rat neutrophils. This study demonstrated that PEP1261 significantly inhibited the effect on the ROS generation as well as the mRNA synthesis and expression of the complement factors in neutrophils isolated from infarct heart.

Novel Tetrazoles against Acanthamoeba castellanii Belonging to the T4 Genotype

Chemotherapy ◽  
2021 ◽  
Author(s):  
Yassmin Isse Wehelie ◽  
Naveed Ahmed Khan ◽  
Itrat Fatima ◽  
Areeba Anwar ◽  
Kanwal Kanwal ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Silver Nanoparticles ◽  
Reactive Oxygen Species Generation ◽  
Acanthamoeba Castellanii ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Species Determination ◽  
One Pot ◽  
Tetrazole Derivatives

Background: Acanthamoeba castellanii is a pathogenic free-living amoeba responsible for blinding keratitis and fatal granulomatous amoebic encephalitis. However, treatments are not standardized but can involve the use of amidines, biguanides, and azoles. Objectives: The aim of this study was to synthesize a variety of synthetic tetrazole derivatives and test their activities against A. castellanii. Methods: A series of novel tetrazole compounds were synthesized by one-pot method and characterized by NMR and mass spectroscopy. These compounds were subjected to amoebicidal, and cytotoxicity assays against A. castellanii belonging to the T4 genotype and human keratinocyte skin cells respectively. Additionally, reactive oxygen species determination and electron microscopy studies were carried out. Furthermore, two of the seven compounds were conjugated with silver nanoparticles to study their antiamoebic potential. Results: A series of seven tetrazole derivatives were synthesized successfully. The selected tetrazoles showed anti-amoebic activities at 10µM concentration against A. castellanii in vitro. The compounds tested caused increased reactive oxygen species generation in A castellanii, and significant morphological damage to amoebal membranes. Moreover, conjugation of silver nanoparticles enhanced antiamoebic effects of two tetrazoles. Conclusions: The results showed that azole compounds hold promise in the development of new formulations of anti-Acanthamoebic agents.

Aspirin-triggered lipoxin A4 blocks reactive oxygen species generation in endothelial cells: A novel antioxidative mechanism

2007 ◽  
Vol 97 (01) ◽  
pp. 88-98 ◽  
Author(s):  
Christina Barja-Fidalgo ◽  
Vany Nascimento-Silva ◽  
Maria Arruda ◽  
Iolanda Fierro
Keyword(s):  
Reactive Oxygen Species ◽  
Endothelial Cells ◽  
Cardiovascular Diseases ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Protective Role ◽  
Ros Generation ◽  
Oxygen Species ◽  
Lipoxin A4 ◽  
Pre Treatment

SummaryLipoxins and their aspirin-triggered carbon-15 epimers have emerged as mediators of key events in endogenous anti-inflammation and resolution. However, the implication of these novel lipid mediators on cardiovascular diseases such as hypertension, atherosclerosis, and heart failure has not been investigated. One of the major features shared by these pathological conditions is the increased production of reactive oxygen species (ROS) generated by vascular NAD(P)H oxidase activation. In this study, we have examined whether an aspirin-triggered lipoxin A4 analog (ATL-1) modulates ROS generation in endothelial cells (EC). Pre-treatment of EC with ATL-1 (1–100 nM) completely blocked ROS production triggered by different agents, as assessed by dihydrorhodamine 123 and hydroethidine. Furthermore, ATL-1 inhibited the phosphorylation and translocation of the cytosplamic NAD(P)H oxidase subunit p47phox to the cell membrane as well as NAD(P)H oxidase activity. Western blot and immunofluorescence microscopy analyses showed that ATL-1 (100 nM) impaired the redox-sensitive activation of the transcriptional factor NF-κB, a critical step in several events associated to vascular pathologies. These results demonstrate that ATL-1 suppresses NAD(P)H oxidase-mediated ROS generation in EC, strongly indicating that lipoxins may play a protective role against the development and progression of cardiovascular diseases.

scholarly journals The Involvement of the Tyrosine Kinase c-Src in the Regulation of Reactive Oxygen Species Generation Mediated by NADPH Oxidase-1

2008 ◽  
Vol 19 (7) ◽  
pp. 2984-2994 ◽  
Author(s):  
Davide Gianni ◽  
Ben Bohl ◽  
Sara A. Courtneidge ◽  
Gary M. Bokoch
Keyword(s):  
Reactive Oxygen Species ◽  
Nadph Oxidase ◽  
Tyrosine Kinase ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Tumor Formation ◽  
Ros Generation ◽  
Oxygen Species ◽  
Human Colon Carcinoma Cell ◽  
Kinase C

NADPH oxidase (Nox) family enzymes are one of the main sources of cellular reactive oxygen species (ROS), which have been shown to function as second messenger molecules. To date, seven members of this family have been reported, including Nox1-5 and Duox1 and -2. With the exception of Nox2, the regulation of the Nox enzymes is still poorly understood. Nox1 is highly expressed in the colon, and it requires two cytosolic regulators, NoxO1 and NoxA1, as well as the binding of Rac1 GTPase, for its activity. In this study, we investigate the role of the tyrosine kinase c-Src in the regulation of ROS formation by Nox1. We show that c-Src induces Nox1-mediated ROS generation in the HT29 human colon carcinoma cell line through a Rac-dependent mechanism. Treatment of HT29 cells with the Src inhibitor PP2, expression of a kinase-inactive form of c-Src, and c-Src depletion by small interfering RNA (siRNA) reduce both ROS generation and the levels of active Rac1. This is associated with decreased Src-mediated phosphorylation and activation of the Rac1-guanine nucleotide exchange factor Vav2. Consistent with this, Vav2 siRNA that specifically reduces endogenous Vav2 protein is able to dramatically decrease Nox1-dependent ROS generation and abolish c-Src-induced Nox1 activity. Together, these results establish c-Src as an important regulator of Nox1 activity, and they may provide insight into the mechanisms of tumor formation in colon cancers.

44 REACTIVE OXYGEN SPECIES IN VITRIFIED BOVINE IN VITRO-MATURED OOCYTES

2012 ◽  
Vol 24 (1) ◽  
pp. 134 ◽  
Author(s):  
M. De Blasi ◽  
M. Rubessa ◽  
G. Albero ◽  
S. Lavrentiadou ◽  
V. Sapanidou ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Sucrose Solution ◽  
Reactive Oxygen ◽  
High Variability ◽  
Atp Depletion ◽  
Calcium Oscillation ◽  
Ros Generation ◽  
Oxygen Species ◽  
Oocyte Vitrification

Vitrification of in vitro-matured oocytes has important applications in fertility preservation and management of genetic resources. However, despite the increasing interest, the efficiency of oocyte vitrification needs to be improved. It was demonstrated that under stressful conditions of cryopreserving pig oocytes accumulate reactive oxygen species (ROS; Gupta et al. 2010 Fertility and Sterility 93, 2602–2607). Reactive oxygen species are known to exert harmful effects such as mitochondrial damage, ATP (ATP) depletion, altered calcium oscillation during fertilization and consequently their developmental ability may be compromised (Takahashi et al. 2003 Mol. Reprod. Dev. 66, 143–152). The aim of the present study was to evaluate whether the exposure to cryoprotectants and vitrification procedure affect ROS production in bovine in vitro-matured oocytes. Abattoir-derived bovine (n = 360, over 6 replicates) cumulus oocyte complexes (COCs), were in vitro-matured. COCs were mechanically stripped of their cumulus cells by gentle pipetting, washed and divided into 3 groups: control (C; i.e. fresh non treated oocytes), toxicity (T) and vitrification (V) groups. In group V, oocytes were exposed to 10% ethylene glycol (EG) + 10% DMSO for 3 min, then to 20% EG + 20% DMSO and 0.5 M sucrose, loaded on cryotops and plunged into liquid nitrogen within 25 s. Oocytes were warmed into a 1.25 M sucrose solution for 1 min and then to decreasing concentrations of sucrose (0.625 M, 0.42 M and 0.31 M) for 30 s each. In group T, oocytes were simply exposed to the vitrification and warming solutions. ROS determination was carried out by a spectrofluorometer at 495 nm excitation and 525 nm emission. Frozen oocytes were thawed and incubated in 500 μL of TRIS-HCl 40 mM, pH 7.0 in the presence of 5 μmol L–1 of 2′,7′-dichlorfluorescein-diacetate, for 20 min at 37°C into a shaker. After incubation, the extraction was obtained by a syringe and the samples were centrifuged at 3000 rpm for 10 min at 4°C. Data were expressed as arbitrary ROS units per oocyte per min (U) and analysed by ANOVA. The results of this study showed that in bovine oocytes ROS levels tend to increase in the T and V groups compared to group C (76.0 ± 6.4, 249.9 ± 87.3 and 147.6 ± 42.6 in C, T and V groups, respectively). However, there were no statistical differences among groups and this was mainly due to the high variability recorded in both treated groups. In conclusion, these results suggest that both exposure to cryoprotectants and vitrification of in vitro-matured oocytes may influence ROS generation. However, the high variability recorded among replicates recommends further investigations.

Reactive Oxygen Species Measured from Suspensions of Polymorphonuclear Leukocytes after the Addition of Silicon Carbide Particles

1996 ◽  
Vol 24 (4) ◽  
pp. 553-556
Author(s):  
Mario Governa ◽  
Matteo Valentino ◽  
Monica Amati ◽  
Francesca Monaco ◽  
Isabella Visoná ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Silicon Carbide ◽  
Reactive Oxygen ◽  
Ros Generation ◽  
Oxygen Species ◽  
Human Polymorphonuclear Leukocyte ◽  
Quartz Dust ◽  
Silicon Carbide Particles ◽  
Carbide Particles

A sample of silicon carbide (SiC) dust was collected from a factory manufacturing SiC abrasives, then tested in vitro to find out whether it could produce reactive oxygen species (ROS) after its addition to human polymorphonuclear leukocyte suspensions. We compared the results of milled and unmilled SiC with those obtained from quartz dust and asbestos fibres, which are known causes of severe pulmonary lesions. ROS production was measured with the chemiluminescence (CD technique. CL values obtained with our two forms of SiC (milled and unmilled) were approximately twice those measured in the controls (where no mineral particles were added), approximately 80% of the values found with asbestos fibres, and only 12.5% of the values measured with quartz. Iron traces were found on the surface of a small number of the particles tested, which could be as a result of contamination. These iron traces could help to explain our findings, since, together with the iron traces present in the culture medium, they could have triggered ROS generation in a Fenton-type reaction.

The Requirement of Reactive Oxygen Species Generation in the Apoptosis of Leukemia Cells Induced by 2-Methoxyestradiol.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4370-4370
Author(s):  
Guo Kunyuan ◽  
Miaorong She ◽  
Haiyan Hu ◽  
Xinqing Niu ◽  
Sanfang Tu ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Leukemia Cell ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Leukemic Cells ◽  
Leukemia Cells ◽  
Ros Generation ◽  
Dependent Manner ◽  
Oxygen Species ◽  
Induced Apoptosis

Abstract 2-Methoxyestradiol (2-ME) is a new anticancer agent currently under investigation for treatment of leukemia. We evaluated the effects of 2-ME-induced apoptosis in two myeloid leukemia cell lines (U937 and HL-60) in association with reactive oxygen species (ROS) generation. We found that 2-ME resulted in viability decrease in a dose-dependent manner, generated ROS: nitric oxide and superoxide anions, and mitochondria damage. 2-ME-induced apoptosis correlated with increase in ROS. Quenching of ROS with N-acetyl-L-cysteine protected leukemia cells from the cytotoxicity of 2-ME and prevented apoptosis induction by 2-ME. Furthermore, addition of manumycin, a farnesyltransferase inhibitor, demonstrated by our previous studies that induced apoptosis of leukemic cells and induced ROS, significantly enhanced the apoptosis-induced by 2-ME. In conclusion, cellular ROS generation play an important role in the cytotoxic effect of 2-ME. It is possible to use ROS-generation agents such as manumycin to enhance the antileukemic effect. Such a combination strategy need the further in vivo justify and may have potential clinical application.

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