scholarly journals Induction of Mitochondrial Reactive Oxygen Species Production by Itraconazole, Terbinafine, and Amphotericin B as a Mode of Action against Aspergillus fumigatus

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Elena Shekhova ◽  
Olaf Kniemeyer ◽  
Axel A. Brakhage
Keyword(s):  
Reactive Oxygen Species ◽  
Lipid Peroxidation ◽  
Aspergillus Fumigatus ◽  
Amphotericin B ◽  
Complex I ◽  
Reactive Oxygen ◽  
Antifungal Compounds ◽  
Ros Production ◽  
Oxygen Species ◽  
Content Type

ABSTRACT Drug resistance in fungal pathogens is of incredible importance to global health, yet the mechanisms of drug action remain only loosely defined. Antifungal compounds have been shown to trigger the intracellular accumulation of reactive oxygen species (ROS) in human-pathogenic yeasts, but the source of those ROS remained unknown. In the present study, we examined the role of endogenous ROS for the antifungal activity of the three different antifungal substances itraconazole, terbinafine, and amphotericin B, which all target the fungal cell membrane. All three antifungals had an impact on fungal redox homeostasis by causing increased intracellular ROS production. Interestingly, the elevated ROS levels induced by antifungals were abolished by inhibition of the mitochondrial respiratory complex I with rotenone. Further, evaluation of lipid peroxidation using the thiobarbituric acid assay revealed that rotenone pretreatment decreased ROS-induced lipid peroxidation during incubation of Aspergillus fumigatus with itraconazole and terbinafine. By applying the mitochondrion-specific lipid peroxidation probe MitoPerOx, we also confirmed that ROS are induced in mitochondria and subsequently cause significant oxidation of mitochondrial membrane in the presence of terbinafine and amphotericin B. To summarize, our study suggests that the induction of ROS production contributes to the ability of antifungal compounds to inhibit fungal growth. Moreover, mitochondrial complex I is the main source of deleterious ROS production in A. fumigatus challenged with antifungal compounds.

scholarly journals The Small GTPase RacA Mediates Intracellular Reactive Oxygen Species Production, Polarized Growth, and Virulence in the Human Fungal Pathogen Aspergillus fumigatus

2010 ◽  
Vol 10 (2) ◽  
pp. 174-186 ◽  
Author(s):  
Haiyan Li ◽  
Bridget M. Barker ◽  
Nora Grahl ◽  
Srisombat Puttikamonkul ◽  
Jeremey D. Bell ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Aspergillus Fumigatus ◽  
Invasive Pulmonary Aspergillosis ◽  
Reactive Oxygen ◽  
Small Gtpase ◽  
Oxygen Species ◽  
Wild Type ◽  
Content Type ◽  
Diphenylene Iodonium

ABSTRACTAspergillus fumigatusis the predominant mold pathogen in immunocompromised patients. In this study, we present the first characterization of the small GTPase RacA inA. fumigatus. To gain insight into the function ofracAin the growth and pathogenesis ofA. fumigatus, we constructed a strain that lacks a functionalracAgene. The ΔracAstrain showed significant morphological defects, including a reduced growth rate and abnormal conidiogenesis on glucose minimal medium. In the ΔracAstrain, apical dominance in the leading hyphae is lost and, instead, multiple axes of polarity emerge. Intriguingly, superoxide production at the hyphal tips was reduced by 25% in the ΔracAstrain. Treatment of wild-type hyphae with diphenylene iodonium, an inhibitor of NADPH oxidase, resulted in phenotypes similar to that of the ΔracAstrain. These data suggest that ΔracAstrain phenotypes may be due to a reduction or alteration in the production of reactive oxygen species. Most surprisingly, despite these developmental and growth abnormalities, the ΔracAstrain retained at least wild-type virulence in both an insect model and two immunologically distinct murine models of invasive pulmonary aspergillosis. These results demonstrate thatin vitrogrowth phenotypes do not always correlate within vivovirulence and raise intriguing questions about the role of RacA inAspergillusvirulence.

scholarly journals Physiologic Implications of Reactive Oxygen Species Production by Mitochondrial Complex I Reverse Electron Transport

Antioxidants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 285 ◽  
Author(s):  
John O. Onukwufor ◽  
Brandon J. Berry ◽  
Andrew P. Wojtovich
Keyword(s):  
Reactive Oxygen Species ◽  
Electron Transport ◽  
Complex I ◽  
Reactive Oxygen ◽  
Reverse Direction ◽  
Mitochondrial Complex I ◽  
Ros Production ◽  
Oxygen Species ◽  
Mitochondrial Complex ◽  
Reverse Electron Transport

Mitochondrial reactive oxygen species (ROS) can be either detrimental or beneficial depending on the amount, duration, and location of their production. Mitochondrial complex I is a component of the electron transport chain and transfers electrons from NADH to ubiquinone. Complex I is also a source of ROS production. Under certain thermodynamic conditions, electron transfer can reverse direction and reduce oxygen at complex I to generate ROS. Conditions that favor this reverse electron transport (RET) include highly reduced ubiquinone pools, high mitochondrial membrane potential, and accumulated metabolic substrates. Historically, complex I RET was associated with pathological conditions, causing oxidative stress. However, recent evidence suggests that ROS generation by complex I RET contributes to signaling events in cells and organisms. Collectively, these studies demonstrate that the impact of complex I RET, either beneficial or detrimental, can be determined by the timing and quantity of ROS production. In this article we review the role of site-specific ROS production at complex I in the contexts of pathology and physiologic signaling.

scholarly journals The Production of Reactive Oxygen Species Is a Universal Action Mechanism of Amphotericin B against Pathogenic Yeasts and Contributes to the Fungicidal Effect of This Drug

2014 ◽  
Vol 58 (11) ◽  
pp. 6627-6638 ◽  
Author(s):  
Ana Cecilia Mesa-Arango ◽  
Nuria Trevijano-Contador ◽  
Elvira Román ◽  
Ruth Sánchez-Fresneda ◽  
Celia Casas ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Amphotericin B ◽  
Reactive Oxygen ◽  
Mitochondrial Respiratory Chain ◽  
Oxygen Species ◽  
Action Mechanism ◽  
Pathogenic Yeast ◽  
Content Type ◽  
Fungicidal Effect ◽  
Killing Action

ABSTRACTAmphotericin B (AMB) is an antifungal drug that binds to ergosterol and forms pores at the cell membrane, causing the loss of ions. In addition, AMB induces the accumulation of reactive oxygen species (ROS), and although these molecules have multiple deleterious effects on fungal cells, their specific role in the action mechanism of AMB remains unknown. In this work, we studied the role of ROS in the action mechanism of AMB. We determined the intracellular induction of ROS in 44 isolates of different pathogenic yeast species (Candida albicans,Candida parapsilosis,Candida glabrata,Candida tropicalis,Candida krusei,Cryptococcus neoformans, andCryptococcus gattii). We also characterized the production of ROS in AMB-resistant isolates. We found that AMB induces the formation of ROS in all the species tested. The inhibition of the mitochondrial respiratory chain by rotenone blocked the induction of ROS by AMB and provided protection from the killing action of the antifungal. Moreover, this phenomenon was absent in strains that displayed resistance to AMB. These strains showed an alteration in the respiration rate and mitochondrial membrane potential and also had higher catalase activity than that of the AMB-susceptible strains. Consistently, AMB failed to induce protein carbonylation in the resistant strains. Our data demonstrate that the production of ROS by AMB is a universal and important action mechanism that is correlated with the fungicidal effect and might explain the low rate of resistance to the molecule. Finally, these data provide an opportunity to design new strategies to improve the efficacy of this antifungal.

scholarly journals Complex I-mediated reactive oxygen species generation: modulation by cytochrome c and NAD(P)+ oxidation–reduction state

2002 ◽  
Vol 368 (2) ◽  
pp. 545-553 ◽  
Author(s):  
Yulia KUSHNAREVA ◽  
Anne N. MURPHY ◽  
Alexander ANDREYEV
Keyword(s):  
Reactive Oxygen Species ◽  
Cytochrome C ◽  
Complex I ◽  
Electron Flow ◽  
Reactive Oxygen ◽  
Complex Iii ◽  
Ros Generation ◽  
Ros Production ◽  
Oxygen Species ◽  
Reduced State

Several lines of evidence indicate that mitochondrial reactive oxygen species (ROS) generation is the major source of oxidative stress in the cell. It has been shown that ROS production accompanies cytochrome c release in different apoptotic paradigms, but the site(s) of ROS production remain obscure. In the current study, we demonstrate that loss of cytochrome c by mitochondria oxidizing NAD+-linked substrates results in a dramatic increase of ROS production and respiratory inhibition. This increased ROS production can be mimicked by rotenone, a complex I inhibitor, as well as other chemical inhibitors of electron flow that act further downstream in the electron transport chain. The effects of cytochrome c depletion from mitoplasts on ROS production and respiration are reversible upon addition of exogenous cytochrome c. Thus in these models of mitochondrial injury, a primary site of ROS generation in both brain and heart mitochondria is proximal to the rotenone inhibitory site, rather than in complex III. ROS production at complex I is critically dependent upon a highly reduced state of the mitochondrial NAD(P)+ pool and is achieved upon nearly complete inhibition of the respiratory chain. Redox clamp experiments using the acetoacetate/d-β-hydroxybutyrate couple in the presence of a maximally inhibitory rotenone concentration suggest that the site is approx. 50mV more electronegative than the NADH/NAD+ couple. In the absence of inhibitors, this highly reduced state of mitochondria can be induced by reverse electron flow from succinate to NAD+, accounting for profound ROS production in the presence of succinate. These results lead us to propose a model of thermodynamic control of mitochondrial ROS production which suggests that the ROS-generating site of complex I is the Fe—S centre N-1a.

Benzene metabolites enhance reactive oxygen species generation in HL60 human leukemia cells

1996 ◽  
Vol 15 (5) ◽  
pp. 422-427 ◽  
Author(s):  
Y. Shen ◽  
H-M. Shen ◽  
C-Y. Shi ◽  
C-N. Ong
Keyword(s):  
Reactive Oxygen Species ◽  
Lipid Peroxidation ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Leukemia Cells ◽  
Ros Generation ◽  
Human Leukemia ◽  
Ros Production ◽  
Oxygen Species ◽  
Ros Formation

Benzene is myelotoxic and leukemogenic in humans. The mechanisms leading to these effects, however have not been fully elucidated. One of the underlying mechanisms is believed to be the oxidative damage caused by its metabolites. A comparative study was undertaken to examine the relationships between reactive oxygen species (ROS) production, lipid peroxidation and subse quent cytotoxicity induced by five major benzene meta bolites. The generation of ROS by benzene metabolites was demonstrated by the significant and dose-dependent increase of intracellular ROS formation in HL60 human promyelocytic leukemia cells in vitro. 1,4-Benzoquinone (BQ) was found to be the most potent metabolite in induction of ROS formation, followed by 1,2,4-benzene triol (BT) and to a lesser extent, phenol (PH) and trans, trans-muconaldehyde (MD). No significant effect was observed when the cells were treated with trans, trans-muconic acid (MA). The enhancement of ROS production by BQ was effectively inhibited by the addition of catalase, deferoxamine (DFO) and dimethyl sulfoxide (DMSO), but unchanged by superoxide dismutase (SOD), suggest that hydrogen peroxide (H2O2) and hydroxyl radicals (OH.) are the two major forms of ROS involved. The results also demonstrate that the ability of benzene metabolites in enhancing ROS generation is closely correlated to their capacity in causing lipid peroxidation and subsequent cytotoxicity. These findings together with earlier parallel observations on DNA damage suggest that ROS play an important role in the mechanism of carcinogenesis induced by benzene metabolites.

scholarly journals Functional Analysis of theTrichoderma harzianum nox1Gene, Encoding an NADPH Oxidase, Relates Production of Reactive Oxygen Species to Specific Biocontrol Activity against Pythium ultimum

2011 ◽  
Vol 77 (9) ◽  
pp. 3009-3016 ◽  
Author(s):  
M. Montero-Barrientos ◽  
R. Hermosa ◽  
R. E. Cardoza ◽  
S. Gutiérrez ◽  
E. Monte
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Pythium Ultimum ◽  
Eukaryotic Cells ◽  
Ros Production ◽  
Oxygen Species ◽  
Wild Type ◽  
Nadph Oxidases ◽  
Content Type ◽  
Biocontrol Activity

ABSTRACTThe synthesis of reactive oxygen species (ROS) is one of the first events following pathogenic interactions in eukaryotic cells, and NADPH oxidases are involved in the formation of such ROS. Thenox1gene ofTrichoderma harzianumwas cloned, and its role in antagonism against phytopathogens was analyzed innox1-overexpressed transformants. The increased levels ofnox1expression in these transformants were accompanied by an increase in ROS production during their direct confrontation withPythium ultimum. The transformants displayed an increased hydrolytic pattern, as determined by comparing protease, cellulase, and chitinase activities with those for the wild type. In confrontation assays againstP. ultimumthenox1-overexpressed transformants were more effective than the wild type, but not in assays againstBotrytis cinereaorRhizoctonia solani. A transcriptomic analysis using aTrichodermahigh-density oligonucleotide (HDO) microarray also showed that, compared to gene expression for the interaction of wild-typeT. harzianumandP. ultimum, genes related to protease, cellulase, and chitinase activities were differentially upregulated in the interaction of anox1-overexpressed transformant with this pathogen. Our results show thatnox1is involved inT. harzianumROS production and antagonism againstP. ultimum.

scholarly journals The Aryl Hydrocarbon Receptor Modulates Production of Cytokines and Reactive Oxygen Species and Development of Myocarditis during Trypanosoma cruzi Infection

2016 ◽  
Vol 84 (10) ◽  
pp. 3071-3082 ◽  
Author(s):  
Andréia Barroso ◽  
Melisa Gualdrón-López ◽  
Lísia Esper ◽  
Fátima Brant ◽  
Ronan R. S. Araújo ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Trypanosoma Cruzi ◽  
Aryl Hydrocarbon Receptor ◽  
Reactive Oxygen ◽  
T Cell Subsets ◽  
Cytokine Signaling ◽  
Ros Production ◽  
Oxygen Species ◽  
Content Type ◽  
Aryl Hydrocarbon

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor involved in controlling several aspects of immune responses, including the activation and differentiation of specific T cell subsets and antigen-presenting cells, thought to be relevant in the context of experimentalTrypanosoma cruziinfection. The relevance of AhR for the outcome ofT. cruziinfection is not known and was investigated here. We infected wild-type (WT) mice and AhR knockout (AhR KO) mice withT. cruzi(Y strain) and determined levels of parasitemia, myocardial inflammation and fibrosis, expression of AhR/cytokines/suppressor of cytokine signaling (SOCS) (spleen/heart), and production of nitric oxide (NO), reactive oxygen species (ROS), and peroxynitrite (ONOO−) (spleen). AhR expression was increased in the heart of infected WT mice. Infected AhR KO mice displayed significantly reduced parasitemia, inflammation, and fibrosis of the myocardium. This was associated with an anticipated increased immune response characterized by increased levels of inflammatory cytokines and reduced expression of SOCS2 and SOCS3 in the heart.In vitro, AhR deficiency caused impairment in parasite replication and decreased levels of ROS production. In conclusion, AhR influences the development of murine Chagas disease by modulating ROS production and regulating the expression of key physiological regulators of inflammation, SOCS1 to -3, associated with the production of cytokines during experimentalT. cruziinfection.

scholarly journals Peroxiredoxin Asp f3 Is Essential for Aspergillus fumigatus To Overcome Iron Limitation during Infection

mBio ◽  
2021 ◽  
Author(s):  
Victor Brantl ◽  
Jana M. Boysen ◽  
Annie Yap ◽  
Evgeny Golubtsov ◽  
Dominik Ruf ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Aspergillus Fumigatus ◽  
Virulence Factor ◽  
Vaccine Candidate ◽  
Reactive Oxygen ◽  
Iron Limitation ◽  
Oxygen Species ◽  
Content Type ◽  
Ros Scavenger ◽  
Fungal Allergen

Asp f3 is one of the most abundant proteins in the pathogenic mold Aspergillus fumigatus . It has an enigmatic multifaceted role as a fungal allergen, virulence factor, reactive oxygen species (ROS) scavenger, and vaccine candidate.

scholarly journals Melanin Protects Paracoccidioides brasiliensis from the Effects of Antimicrobial Photodynamic Inhibition and Antifungal Drugs

2015 ◽  
Vol 59 (7) ◽  
pp. 4003-4011 ◽  
Author(s):  
Ludmila Matos Baltazar ◽  
Silvia Maria Cordeiro Werneck ◽  
Betânia Maria Soares ◽  
Marcus Vinicius L. Ferreira ◽  
Danielle G. Souza ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Reactive Oxygen Species ◽  
Amphotericin B ◽  
Reactive Oxygen ◽  
Antifungal Drugs ◽  
Yeast Cells ◽  
Health Concern ◽  
Oxygen Species ◽  
Protective Function ◽  
Content Type

ABSTRACTParacoccidioidomycosis (PCM) is a public health concern in Latin America and South America that when not correctly treated can lead to patient death. In this study, the influence of melanin produced byParacoccidioidesspp. on the effects of treatment with antimicrobial photodynamic inhibition (aPI) and antifungal drugs was evaluated. aPI was performed using toluidine blue (TBO) as a photosensitizer and a 630-nm light-emitting diode (LED) light. The antifungals tested were itraconazole and amphotericin B. We evaluated the effects of each approach, aPI or antifungals, against nonmelanized and melanized yeast cells by performing susceptibility tests and by quantifying oxidative and nitrosative bursts during the experiments. aPI reduced nonmelanized cells by 3.0 log units and melanized cells by 1.3 log units. The results showed that melanization protects the fungal cell, probably by acting as a scavenger of nitric oxide and reactive oxygen species, but not of peroxynitrite. Melanin also increased the MICs of itraconazole and amphotericin B, and the drugs were fungicidal for nonmelanized and fungistatic for melanized yeast cells. Our study shows that melanin production byParacoccidioidesyeast cells serves a protective function during aPI and treatment with itraconazole and amphotericin B. The results suggest that melanin binds to the drugs, changing their antifungal activities, and also acts as a scavenger of reactive oxygen species and nitric oxide, but not of peroxynitrite, indicating that peroxynitrite is the main radical that is responsible for fungal death after aPI.

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