The Antimalarial Activities of Methylene Blue and the 1,4-Naphthoquinone 3-[4-(Trifluoromethyl)Benzyl]-Menadione Are Not Due to Inhibition of the Mitochondrial Electron Transport Chain

ABSTRACTMethylene blue and a series of recently developed 1,4-naphthoquinones, including 3-[4-(substituted)benzyl]-menadiones, are potent antimalarial agentsin vitroandin vivo. The activity of these structurally diverse compounds against the human malaria parasitePlasmodium falciparummight involve their peculiar redox properties. According to the current theory, redox-active methylene blue and 3-[4-(trifluoromethyl)benzyl]-menadione are “subversive substrates.” These agents are thought to shuttle electrons from reduced flavoproteins to acceptors such as hemoglobin-associated or free Fe(III)-protoporphyrin IX. The reduction of Fe(III)-protoporphyrin IX could subsequently prevent essential hemoglobin digestion and heme detoxification in the parasite. Alternatively, owing to their structures and redox properties, methylene blue and 1,4-naphthoquinones might also affect the mitochondrial electron transport chain. Here, we tested the latter hypothesis using an established system of transgenicP. falciparumcell lines and the antimalarial agents atovaquone and chloroquine as controls. In contrast to atovaquone, methylene blue and 3-[4-(trifluoromethyl)benzyl]-menadione do not inhibit the mitochondrial electron transport chain. A systematic comparison of the morphologies of drug-treated parasites furthermore suggests that the three drugs do not share a mechanism of action. Our findings support the idea that methylene blue and 3-[4-(trifluoromethyl)benzyl]-menadione exert their antimalarial activity as redox-active subversive substrates.

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Genomic, Proteomic, and Biochemical Analysis of the Organohalide Respiratory Pathway in Desulfitobacterium dehalogenans

Journal of Bacteriology ◽

10.1128/jb.02370-14 ◽

2014 ◽

Vol 197 (5) ◽

pp. 893-904 ◽

Cited By ~ 25

Author(s):

Thomas Kruse ◽

Bram A. van de Pas ◽

Ariane Atteia ◽

Klaas Krab ◽

Wilfred R. Hagen ◽

...

Keyword(s):

Electron Transport ◽

Electron Acceptor ◽

Electron Transport Chain ◽

Biochemical Analysis ◽

Active Components ◽

Organohalide Respiration ◽

Content Type ◽

Membrane Complex ◽

Redox Active ◽

Transport Chain

Desulfitobacterium dehalogenansis able to grow by organohalide respiration using 3-chloro-4-hydroxyphenyl acetate (Cl-OHPA) as an electron acceptor. We used a combination of genome sequencing, biochemical analysis of redox active components, and shotgun proteomics to study elements of the organohalide respiratory electron transport chain. The genome ofDesulfitobacterium dehalogenansJW/IU-DC1Tconsists of a single circular chromosome of 4,321,753 bp with a GC content of 44.97%. The genome contains 4,252 genes, including six rRNA operons and six predicted reductive dehalogenases. One of the reductive dehalogenases, CprA, is encoded by a well-characterizedcprTKZEBACDgene cluster. Redox active components were identified in concentrated suspensions of cells grown on formate and Cl-OHPA or formate and fumarate, using electron paramagnetic resonance (EPR), visible spectroscopy, and high-performance liquid chromatography (HPLC) analysis of membrane extracts. In cell suspensions, these components were reduced upon addition of formate and oxidized after addition of Cl-OHPA, indicating involvement in organohalide respiration. Genome analysis revealed genes that likely encode the identified components of the electron transport chain from formate to fumarate or Cl-OHPA. Data presented here suggest that the first part of the electron transport chain from formate to fumarate or Cl-OHPA is shared. Electrons are channeled from an outward-facing formate dehydrogenase via menaquinones to a fumarate reductase located at the cytoplasmic face of the membrane. When Cl-OHPA is the terminal electron acceptor, electrons are transferred from menaquinones to outward-facing CprA, via an as-yet-unidentified membrane complex, and potentially an extracellular flavoprotein acting as an electron shuttle between the quinol dehydrogenase membrane complex and CprA.

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Variation among Plasmodium falciparum Strains in Their Reliance on Mitochondrial Electron Transport Chain Function

Eukaryotic Cell ◽

10.1128/ec.05049-11 ◽

2011 ◽

Vol 10 (8) ◽

pp. 1053-1061 ◽

Cited By ~ 36

Author(s):

Hangjun Ke ◽

Joanne M. Morrisey ◽

Suresh M. Ganesan ◽

Heather J. Painter ◽

Michael W. Mather ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Electron Transport ◽

Electron Transport Chain ◽

Single Copy ◽

Mitochondrial Electron Transport Chain ◽

Growth Responses ◽

Content Type ◽

Transport Chain ◽

Transgenic Lines ◽

Transgenic Parasites

ABSTRACT Previous studies demonstrated that Plasmodium falciparum strain D10 became highly resistant to the mitochondrial electron transport chain (mtETC) inhibitor atovaquone when the mtETC was decoupled from the pyrimidine biosynthesis pathway by expressing the fumarate-dependent (ubiquinone-independent) yeast dihydroorotate dehydrogenase (yDHODH) in parasites. To investigate the requirement for decoupled mtETC activity in P. falciparum with different genetic backgrounds, we integrated a single copy of the yDHODH gene into the genomes of D10attB, 3D7attB, Dd2attB, and HB3attB strains of the parasite. The yDHODH gene was equally expressed in all of the transgenic lines. All four yDHODH transgenic lines showed strong resistance to atovaquone in standard short-term growth inhibition assays. During longer term growth with atovaquone, D10attB-yDHODH and 3D7attB-yDHODH parasites remained fully resistant, but Dd2attB-yDHODH and HB3attB-yDHODH parasites lost their tolerance to the drug after 3 to 4 days of exposure. No differences were found, however, in growth responses among all of these strains to the Plasmodium -specific DHODH inhibitor DSM1 in either short- or long-term exposures. Thus, DSM1 works well as a selective agent in all parasite lines transfected with the yDHODH gene, whereas atovaquone works for some lines. We found that the ubiquinone analog decylubiquinone substantially reversed the atovaquone inhibition of Dd2attB-yDHODH and HB3attB-yDHODH transgenic parasites during extended growth. Thus, we conclude that there are strain-specific differences in the requirement for mtETC activity among P. falciparum strains, suggesting that, in erythrocytic stages of the parasite, ubiquinone-dependent dehydrogenase activities other than those of DHODH are dispensable in some strains but are essential in others.

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AB0031 T HELPER 17 CELLS WERE SIGNIFICANTLY DECREASED BY MITOCHONDRIAL ELECTRON TRANSPORT CHAIN COMPLEX INHIBITOR IN PATIENTS WITH RHEUMATOID ARTHRITIS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.3441 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 1318.2-1318

Author(s):

H. R. Lee ◽

S. J. Yoo ◽

J. Kim ◽

I. S. Yoo ◽

C. K. Park ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Electron Transport ◽

Disease Activity ◽

Th17 Cells ◽

Electron Transport Chain ◽

Chain Complex ◽

Complex Iii ◽

Mitochondrial Electron Transport Chain ◽

Transport Chain ◽

Healthy Control

Background:Reactive oxygen species (ROS) and T helper 17 (TH17) cells have been known to play an important role in the pathogenesis of rheumatoid arthritis (RA). However, the interrelationship between ROS and TH17 remains unclear in RAObjectives:To explore whether ROS affect TH17 cells in peripheral blood mononuclear cells (PBMC) of RA patients, we analyzed ROS expressions among T cell subsets following treatment with mitochondrial electron transport chain complex inhibitors.Methods:Blood samples were collected from 40 RA patients and 10 healthy adult volunteers. RA activity was divided according to clinical parameter DAS28. PBMC cells were obtained from the whole blood using lymphocyte separation medium density gradient centrifugation. Following PBMC was stained with Live/Dead stain dye, cells were incubated with antibodies for CD3, CD4, CD8, and CD25. After fixation and permeabilization, samples were stained with antibodies for FoxP3 and IL-17A. MitoSox were used for mitochondrial specific staining.Results:The frequency of TH17 cells was increased by 4.83 folds in moderate disease activity group (5.1>DAS28≥3.2) of RA patients compared to healthy control. Moderate RA activity patients also showed higher ratio of TH17/Treg than healthy control (3.57 folds). All RA patients had elevated expression of mitochondrial specific ROS than healthy control. When PBMC cells were treated with 2.5uM of antimycin A (mitochondrial electron transport chain complex III inhibitor) for 16 h, the frequency of TH17 cells was significantly decreased.Conclusion:The mitochondrial electron transport chain complex III inhibitor markedly downregulated the frequency of TH17 cells in moderate disease activity patients with RA. These findings provide a novel approach to regulate TH17 function in RA through mitochondrial metabolism related ROS production.References:[1]Szekanecz, Z., et al., New insights in synovial angiogenesis. Joint Bone Spine, 2010. 77(1): p. 13-9.[2]Prevoo, M.L., et al., Modified disease activity scores that include twenty-eight-joint counts. Development and validation in a prospective longitudinal study of patients with rheumatoid arthritis. Arthritis Rheum, 1995. 38(1): p. 44-8.Disclosure of Interests:None declared

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Dysfunction in Mitochondrial Electron Transport Chain Complex I, Pyruvate Dehydrogenase Activity, and Mutations in ND1 and ND4 Gene in Autism Spectrum Disorder Subjects from Tamil Nadu Population, India

Molecular Neurobiology ◽

10.1007/s12035-021-02492-w ◽

2021 ◽

Author(s):

Iyer Mahalaxmi ◽

Mohana Devi Subramaniam ◽

Abilash Valsala Gopalakrishnan ◽

Balachandar Vellingiri

Keyword(s):

Autism Spectrum Disorder ◽

Electron Transport ◽

Pyruvate Dehydrogenase ◽

Complex I ◽

Electron Transport Chain ◽

Tamil Nadu ◽

Chain Complex ◽

Autism Spectrum ◽

Mitochondrial Electron Transport Chain ◽

Transport Chain

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Anticancer gold(iii)-bisphosphine complex alters the mitochondrial electron transport chain to induce in vivo tumor inhibition

Chemical Science ◽

10.1039/d1sc01418h ◽

2021 ◽

Author(s):

Jong Hyun Kim ◽

Samuel Ofori ◽

Sean Parkin ◽

Hemendra Vekaria ◽

Patrick G. Sullivan ◽

...

Keyword(s):

Electron Transport ◽

Metal Complexes ◽

Electron Transport Chain ◽

Chemical Diversity ◽

Mitochondrial Electron Transport Chain ◽

Generate Functional ◽

Tumor Inhibition ◽

Transport Chain

Expanding the chemical diversity of metal complexes provides a robust platform to generate functional bioactive reagents.

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New inhibitors of Complex I of the mitochondrial electron transport chain with activity as pesticides

Biochemical Society Transactions ◽

10.1042/bst0220230 ◽

1994 ◽

Vol 22 (1) ◽

pp. 230-233 ◽

Cited By ~ 90

Author(s):

Robert M. Hollingworth ◽

Kabeer I. Ahammadsahib ◽

G. Gadelhak ◽

J. L. McLaughlin

Keyword(s):

Electron Transport ◽

Complex I ◽

Electron Transport Chain ◽

Mitochondrial Electron Transport Chain ◽

Transport Chain

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Mitochondrial electron transport chain dysfunction during development does not extend lifespan in Drosophila melanogaster

Mechanisms of Ageing and Development ◽

10.1016/j.mad.2010.01.004 ◽

2010 ◽

Vol 131 (2) ◽

pp. 156-164 ◽

Cited By ~ 10

Author(s):

Michael Rera ◽

Véronique Monnier ◽

Hervé Tricoire

Keyword(s):

Drosophila Melanogaster ◽

Electron Transport ◽

Electron Transport Chain ◽

Mitochondrial Electron Transport Chain ◽

Transport Chain

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Physiological Evidence for Isopotential Tunneling in the Electron Transport Chain of Methane-Producing Archaea

Applied and Environmental Microbiology ◽

10.1128/aem.00950-17 ◽

2017 ◽

Vol 83 (18) ◽

Cited By ~ 5

Author(s):

Nikolas Duszenko ◽

Nicole R. Buan

Keyword(s):

Escherichia Coli ◽

Electron Transport ◽

Stationary Phase ◽

Exponential Growth ◽

Electron Transport Chain ◽

Methanosarcina Barkeri ◽

Metabolic Efficiency ◽

Methanosarcina Acetivorans ◽

Content Type ◽

Transport Chain

ABSTRACT Many, but not all, organisms use quinones to conserve energy in their electron transport chains. Fermentative bacteria and methane-producing archaea (methanogens) do not produce quinones but have devised other ways to generate ATP. Methanophenazine (MPh) is a unique membrane electron carrier found in Methanosarcina species that plays the same role as quinones in the electron transport chain. To extend the analogy between quinones and MPh, we compared the MPh pool sizes between two well-studied Methanosarcina species, Methanosarcina acetivorans C2A and Methanosarcina barkeri Fusaro, to the quinone pool size in the bacterium Escherichia coli. We found the quantity of MPh per cell increases as cultures transition from exponential growth to stationary phase, and absolute quantities of MPh were 3-fold higher in M. acetivorans than in M. barkeri. The concentration of MPh suggests the cell membrane of M. acetivorans, but not of M. barkeri, is electrically quantized as if it were a single conductive metal sheet and near optimal for rate of electron transport. Similarly, stationary (but not exponentially growing) E. coli cells also have electrically quantized membranes on the basis of quinone content. Consistent with our hypothesis, we demonstrated that the exogenous addition of phenazine increases the growth rate of M. barkeri three times that of M. acetivorans. Our work suggests electron flux through MPh is naturally higher in M. acetivorans than in M. barkeri and that hydrogen cycling is less efficient at conserving energy than scalar proton translocation using MPh. IMPORTANCE Can we grow more from less? The ability to optimize and manipulate metabolic efficiency in cells is the difference between commercially viable and nonviable renewable technologies. Much can be learned from methane-producing archaea (methanogens) which evolved a successful metabolic lifestyle under extreme thermodynamic constraints. Methanogens use highly efficient electron transport systems and supramolecular complexes to optimize electron and carbon flow to control biomass synthesis and the production of methane. Worldwide, methanogens are used to generate renewable methane for heat, electricity, and transportation. Our observations suggest Methanosarcina acetivorans, but not Methanosarcina barkeri, has electrically quantized membranes. Escherichia coli, a model facultative anaerobe, has optimal electron transport at the stationary phase but not during exponential growth. This study also suggests the metabolic efficiency of bacteria and archaea can be improved using exogenously supplied lipophilic electron carriers. The enhancement of methanogen electron transport through methanophenazine has the potential to increase renewable methane production at an industrial scale.

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