The role of Trypanosoma brucei MRPA in melarsoprol susceptibility.
We previously showed that over-expression of Trypanosoma brucei MRPA, a member of the multidrug resistance protein family in T. brucei, reproducibly resulted in resistance to the anti-trypanosomal drug melarsoprol in vitro. MRPA is predicted to mediate efflux of melarsoprol as a conjugate with trypanothione, a glutathione-spermidine conjugate which is the major small thiol in trypanosomes. Here, we show that depletion of MRPA by RNA interference resulted in moderate hypersensitivity to both melarsoprol and melarsen oxide. Over-expression of MRPA alone is not sufficient to cause melarsoprol resistance in vivo, although it is sufficient in vitro. This discrepancy is not an effect of drug metabolism since over-expression of MRPA alone conferred resistance to melarsoprol and its principle metabolite, melarsen oxide, in vitro. Over-expression of MRPA was not detected in four melarsoprol-resistant trypanosome isolates from sleeping sickness patients.
Alibu
Vincent P
VP
Universitat Heidelberg, Zentrum fur Molekulare Biologie (ZMBH), Im Neuenheimer Feld 282, D69120 Heidelberg, Germany.
Richter
Christina
C
Voncken
Frank
F
Marti
Gabriela
G
Shahi
Sanjay
S
Renggli
Christina Kunz
CK
Seebeck
Thomas
T
Brun
Reto
R
Clayton
Christine
C
D000818:Animals; D001152:Arsenicals / Q000494:pharmacology; D015153:Blotting, Western / Q000379:methods; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D015870:Gene Expression; D006801:Humans; D008549:Melarsoprol / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D026901:Membrane Transport Proteins / Q000032:analysis / Q000096:biosynthesis / Q000502:physiology*; D051379:Mice; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000032:analysis / Q000096:biosynthesis / Q000502:physiology*; D021261:Parasitic Sensitivity Tests / Q000379:methods; D015800:Protozoan Proteins / Q000032:analysis / Q000096:biosynthesis / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017211:Treatment Failure; D014344:Trypanocidal Agents / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D014346:Trypanosoma brucei brucei / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D014353:Trypanosomiasis, African / Q000188:drug therapy / Q000469:parasitology*
D001152:Arsenicals; D008549:Melarsoprol; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D015800:Protozoan Proteins; D014344:Trypanocidal Agents; C461386:MRPA protein, Trypanosoma brucei; C044719:melarsen oxide