title: Low plasma membrane expression of the miltefosine transport complex renders Leishmania braziliensis refractory to the drug.
abstract: Miltefosine (hexadecylphosphocholine, MLF) is the first oral drug with recognized efficacy against both visceral and cutaneous leishmaniasis. However, some clinical studies have suggested that MLF shows significantly less efficiency against the cutaneous leishmaniasis caused by Leishmania braziliensis. In this work, we have determined the cellular and molecular basis for the natural MLF resistance observed in L. braziliensis. Four independent L. braziliensis clinical isolates showed a marked decrease in MLF sensitivity that was due to their inability to internalize the drug. MLF internalization in the highly sensitive L. donovani species requires at least two proteins in the plasma membrane, LdMT, a P-type ATPase involved in phospholipid translocation, and its beta subunit, LdRos3. Strikingly, L. braziliensis parasites showed highly reduced levels of this MLF translocation machinery at the plasma membrane, mainly because of the low expression levels of the beta subunit, LbRos3. Overexpression of LbRos3 induces increased MLF sensitivity not only in L. braziliensis promastigotes but also in intracellular amastigotes. These results further highlight the importance of the MLF translocation machinery in determining MLF potency and point toward the development of protocols to routinely monitor MLF susceptibility in geographic areas where L. braziliensis might be prevalent.
authors.affiliation: Instituto de Parasitología y Biomedicina López-Neyra, CSIC, Parque Tecnológico de Ciencias de la Salud, Armilla, Granada, Spain. castanys@ipb.csic.es
authors.forename: María P
authors.initials: MP
authors.lastname: Sánchez-Cañete
authors.forename: Luís
authors.initials: L
authors.lastname: Carvalho
authors.forename: F Javier
authors.initials: FJ
authors.lastname: Pérez-Victoria
authors.forename: Francisco
authors.initials: F
authors.lastname: Gamarro
authors.forename: Santiago
authors.initials: S
authors.lastname: Castanys
mesh_terms: D000251:Adenosine Triphosphatases / Q000032:analysis* / Q000502:physiology; D000818:Animals; D000981:Antiprotozoal Agents / Q000493:pharmacokinetics*; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D004351:Drug Resistance; D007892:Leishmania braziliensis / Q000187:drug effects*; D026901:Membrane Transport Proteins / Q000032:analysis* / Q000502:physiology; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology; D015800:Protozoan Proteins / Q000032:analysis / Q000502:physiology
chemical_list: D000981:Antiprotozoal Agents; D026901:Membrane Transport Proteins; D015800:Protozoan Proteins; D010767:Phosphorylcholine; C039128:miltefosine; D000251:Adenosine Triphosphatases