Linked Life Data

19415801

Source:http://linkedlifedata.com/resource/pubmed/id/19415801

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2009-5-4
pubmed:abstractText
Infections with the microaerophilic parasite Trichomonas vaginalis are treated with the 5-nitroimidazole drug metronidazole, which is also in use against Entamoeba histolytica, Giardia intestinalis and microaerophilic/anaerobic bacteria. Here we report that in T. vaginalis the flavin enzyme thioredoxin reductase displays nitroreductase activity with nitroimidazoles, including metronidazole, and with the nitrofuran drug furazolidone. Reactive metabolites of metronidazole and other nitroimidazoles form covalent adducts with several proteins that are known or assumed to be associated with thioredoxin-mediated redox regulation, including thioredoxin reductase itself, ribonucleotide reductase, thioredoxin peroxidase and cytosolic malate dehydrogenase. Disulphide reducing activity of thioredoxin reductase was greatly diminished in extracts of metronidazole-treated cells and intracellular non-protein thiol levels were sharply decreased. We generated a highly metronidazole-resistant cell line that displayed only minimal thioredoxin reductase activity, not due to diminished expression of the enzyme but due to the lack of its FAD cofactor. Reduction of free flavins, readily observed in metronidazole-susceptible cells, was also absent in the resistant cells. On the other hand, iron-depleted T. vaginalis cells, expressing only minimal amounts of PFOR and hydrogenosomal malate dehydrogenase, remained fully susceptible to metronidazole. Thus, taken together, our data suggest a flavin-based mechanism of metronidazole activation and thereby challenge the current model of hydrogenosomal activation of nitroimidazole drugs.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1365-2958
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
72
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
518-36
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Trichomonas vaginalis: metronidazole and other nitroimidazole drugs are reduced by the flavin enzyme thioredoxin reductase and disrupt the cellular redox system. Implications for nitroimidazole toxicity and resistance.
pubmed:affiliation
Department of Specific Prophylaxis and Tropical Medicine at the Center for Physiology, Pathophysiology and Immunology, Medical University of Vienna, Vienna, Austria. david.leitsch@meduniwien.ac.at
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't