Functional Validation of ABCA3 as a Miltefosine Transporter in Human Macrophages: Impact on Intracellular Survival of Leishmania (Viannia) panamensis
2016 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 291, no 18, 9638-9647 p.Article in journal (Refereed) Published
Within its mammalian host, Leishmania resides and replicates as an intracellular parasite. The direct activity of antileishmanials must therefore depend on host intracellular drug transport, metabolism and accumulation. In this study, we explored the role of human macrophage transporters in the intracellular accumulation and antileishmanial activity of miltefosine (MLF), the only oral drug available for the treatment of visceral and cutaneous leishmaniasis (CL). Membrane transporter gene expression in primary human macrophages infected in vitro with L.V. panamensis and exposed to MLF showed modulation of ABC and SLC transporters gene transcripts. Among these, ABCA3, a lipid transporter, was significantly induced after exposure to MLF and this induction was confirmed in primary macrophages from CL patients. Functional validation of MLF as a substrate for ABCA3 was performed by shRNA gene knockdown (KD) in THP-1 monocytes. Intracellular accumulation of radiolabelled-MLF was significantly higher in ABCA3KD macrophages. ABCA3KD resulted in increased cytotoxicity induced by MLF exposure. ABCA3 gene expression inversely correlated with intracellular MLF content in primary macrophages from CL patients. ABCA3KD reduced parasite survival during macrophage infection with an L.V. panamensis strain exhibiting low in vitro susceptibility to MLF. Confocal microscopy showed ABCA3 to be located in the cell membrane of resting macrophages, and in intracellular compartments in L.V. panamensis infected cells. These results provide evidence of ABCA3 as an MLF efflux transporter in human macrophages, and support its role in the direct antileishmanial effect of this alkylphosphocholine drug.
Place, publisher, year, edition, pages
2016. Vol. 291, no 18, 9638-9647 p.
IdentifiersURN: urn:nbn:se:uu:diva-279087DOI: 10.1074/jbc.M115.688168ISI: 000375602300022PubMedID: 26903515OAI: oai:DiVA.org:uu-279087DiVA: diva2:907517