Aquaporin 2 mutations in Trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol.
The predominant mechanism of drug resistance in African trypanosomes is decreased drug uptake due to loss-of-function mutations in the genes for the transporters that mediate drug import. The role of transporters as determinants of drug susceptibility is well documented from laboratory-selected Tryp...
Saved in:
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2013-01-01
|
| Series: | PLoS Neglected Tropical Diseases |
| Online Access: | https://doi.org/10.1371/journal.pntd.0002475 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850212688748085248 |
|---|---|
| author | Fabrice E Graf Philipp Ludin Tanja Wenzler Marcel Kaiser Reto Brun Patient Pati Pyana Philippe Büscher Harry P de Koning David Horn Pascal Mäser |
| author_facet | Fabrice E Graf Philipp Ludin Tanja Wenzler Marcel Kaiser Reto Brun Patient Pati Pyana Philippe Büscher Harry P de Koning David Horn Pascal Mäser |
| author_sort | Fabrice E Graf |
| collection | DOAJ |
| description | The predominant mechanism of drug resistance in African trypanosomes is decreased drug uptake due to loss-of-function mutations in the genes for the transporters that mediate drug import. The role of transporters as determinants of drug susceptibility is well documented from laboratory-selected Trypanosoma brucei mutants. But clinical isolates, especially of T. b. gambiense, are less amenable to experimental investigation since they do not readily grow in culture without prior adaptation. Here we analyze a selected panel of 16 T. brucei ssp. field isolates that (i) have been adapted to axenic in vitro cultivation and (ii) mostly stem from treatment-refractory cases. For each isolate, we quantify the sensitivity to melarsoprol, pentamidine, and diminazene, and sequence the genomic loci of the transporter genes TbAT1 and TbAQP2. The former encodes the well-characterized aminopurine permease P2 which transports several trypanocides including melarsoprol, pentamidine, and diminazene. We find that diminazene-resistant field isolates of T. b. brucei and T. b. rhodesiense carry the same set of point mutations in TbAT1 that was previously described from lab mutants. Aquaglyceroporin 2 has only recently been identified as a second transporter involved in melarsoprol/pentamidine cross-resistance. Here we describe two different kinds of TbAQP2 mutations found in T. b. gambiense field isolates: simple loss of TbAQP2, or loss of wild-type TbAQP2 allele combined with the formation of a novel type of TbAQP2/3 chimera. The identified mutant T. b. gambiense are 40- to 50-fold less sensitive to pentamidine and 3- to 5-times less sensitive to melarsoprol than the reference isolates. We thus demonstrate for the first time that rearrangements of the TbAQP2/TbAQP3 locus accompanied by TbAQP2 gene loss also occur in the field, and that the T. b. gambiense carrying such mutations correlate with a significantly reduced susceptibility to pentamidine and melarsoprol. |
| format | Article |
| id | doaj-art-4c9e2f15f0ea417984d4ef3c091acb31 |
| institution | OA Journals |
| issn | 1935-2727 1935-2735 |
| language | English |
| publishDate | 2013-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Neglected Tropical Diseases |
| spelling | doaj-art-4c9e2f15f0ea417984d4ef3c091acb312025-08-20T02:09:17ZengPublic Library of Science (PLoS)PLoS Neglected Tropical Diseases1935-27271935-27352013-01-01710e247510.1371/journal.pntd.0002475Aquaporin 2 mutations in Trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol.Fabrice E GrafPhilipp LudinTanja WenzlerMarcel KaiserReto BrunPatient Pati PyanaPhilippe BüscherHarry P de KoningDavid HornPascal MäserThe predominant mechanism of drug resistance in African trypanosomes is decreased drug uptake due to loss-of-function mutations in the genes for the transporters that mediate drug import. The role of transporters as determinants of drug susceptibility is well documented from laboratory-selected Trypanosoma brucei mutants. But clinical isolates, especially of T. b. gambiense, are less amenable to experimental investigation since they do not readily grow in culture without prior adaptation. Here we analyze a selected panel of 16 T. brucei ssp. field isolates that (i) have been adapted to axenic in vitro cultivation and (ii) mostly stem from treatment-refractory cases. For each isolate, we quantify the sensitivity to melarsoprol, pentamidine, and diminazene, and sequence the genomic loci of the transporter genes TbAT1 and TbAQP2. The former encodes the well-characterized aminopurine permease P2 which transports several trypanocides including melarsoprol, pentamidine, and diminazene. We find that diminazene-resistant field isolates of T. b. brucei and T. b. rhodesiense carry the same set of point mutations in TbAT1 that was previously described from lab mutants. Aquaglyceroporin 2 has only recently been identified as a second transporter involved in melarsoprol/pentamidine cross-resistance. Here we describe two different kinds of TbAQP2 mutations found in T. b. gambiense field isolates: simple loss of TbAQP2, or loss of wild-type TbAQP2 allele combined with the formation of a novel type of TbAQP2/3 chimera. The identified mutant T. b. gambiense are 40- to 50-fold less sensitive to pentamidine and 3- to 5-times less sensitive to melarsoprol than the reference isolates. We thus demonstrate for the first time that rearrangements of the TbAQP2/TbAQP3 locus accompanied by TbAQP2 gene loss also occur in the field, and that the T. b. gambiense carrying such mutations correlate with a significantly reduced susceptibility to pentamidine and melarsoprol.https://doi.org/10.1371/journal.pntd.0002475 |
| spellingShingle | Fabrice E Graf Philipp Ludin Tanja Wenzler Marcel Kaiser Reto Brun Patient Pati Pyana Philippe Büscher Harry P de Koning David Horn Pascal Mäser Aquaporin 2 mutations in Trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol. PLoS Neglected Tropical Diseases |
| title | Aquaporin 2 mutations in Trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol. |
| title_full | Aquaporin 2 mutations in Trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol. |
| title_fullStr | Aquaporin 2 mutations in Trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol. |
| title_full_unstemmed | Aquaporin 2 mutations in Trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol. |
| title_short | Aquaporin 2 mutations in Trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol. |
| title_sort | aquaporin 2 mutations in trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol |
| url | https://doi.org/10.1371/journal.pntd.0002475 |
| work_keys_str_mv | AT fabriceegraf aquaporin2mutationsintrypanosomabruceigambiensefieldisolatescorrelatewithdecreasedsusceptibilitytopentamidineandmelarsoprol AT philippludin aquaporin2mutationsintrypanosomabruceigambiensefieldisolatescorrelatewithdecreasedsusceptibilitytopentamidineandmelarsoprol AT tanjawenzler aquaporin2mutationsintrypanosomabruceigambiensefieldisolatescorrelatewithdecreasedsusceptibilitytopentamidineandmelarsoprol AT marcelkaiser aquaporin2mutationsintrypanosomabruceigambiensefieldisolatescorrelatewithdecreasedsusceptibilitytopentamidineandmelarsoprol AT retobrun aquaporin2mutationsintrypanosomabruceigambiensefieldisolatescorrelatewithdecreasedsusceptibilitytopentamidineandmelarsoprol AT patientpatipyana aquaporin2mutationsintrypanosomabruceigambiensefieldisolatescorrelatewithdecreasedsusceptibilitytopentamidineandmelarsoprol AT philippebuscher aquaporin2mutationsintrypanosomabruceigambiensefieldisolatescorrelatewithdecreasedsusceptibilitytopentamidineandmelarsoprol AT harrypdekoning aquaporin2mutationsintrypanosomabruceigambiensefieldisolatescorrelatewithdecreasedsusceptibilitytopentamidineandmelarsoprol AT davidhorn aquaporin2mutationsintrypanosomabruceigambiensefieldisolatescorrelatewithdecreasedsusceptibilitytopentamidineandmelarsoprol AT pascalmaser aquaporin2mutationsintrypanosomabruceigambiensefieldisolatescorrelatewithdecreasedsusceptibilitytopentamidineandmelarsoprol |