title: LDL uptake by Leishmania amazonensis: involvement of membrane lipid microdomains.
abstract: Leishmania amazonensis lacks a de novo mechanism for cholesterol synthesis and therefore must scavenge this lipid from the host environment. In this study we show that the L. amazonensis takes up and metabolizes human LDL(1) particles in both a time and dose-dependent manner. This mechanism implies the presence of a true LDL receptor because the uptake is blocked by both low temperature and by the excess of non-labelled LDL. This receptor is probably associated with specific microdomains in the membrane of the parasite, such as rafts, because this process is blocked by methyl-β-cyclodextrin (MCBD). Cholesteryl ester fluorescently-labeled LDL (BODIPY-cholesteryl-LDL) was used to follow the intracellular distribution of this lipid. After uptake it was localized in large compartments along the parasite body. The accumulation of LDL was analyzed by flow cytometry using FITC-labeled LDL particles. Together these data show for the first time that L. amazonensis is able to compensate for its lack of lipid synthesis through the use of a lipid importing machinery largely based on the uptake of LDL particles from the host. Understanding the details of the molecular events involved in this mechanism may lead to the identification of novel targets to block Leishmania infection in human hosts.
authors.affiliation: Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21.941-902, Brazil.
authors.forename: Nuccia N T
authors.initials: NN
authors.lastname: De Cicco
authors.forename: Miria G
authors.initials: MG
authors.lastname: Pereira
authors.forename: José R
authors.initials: JR
authors.lastname: Corrêa
authors.forename: Valter V
authors.initials: VV
authors.lastname: Andrade-Neto
authors.forename: Felipe B
authors.initials: FB
authors.lastname: Saraiva
authors.forename: Alessandra C
authors.initials: AC
authors.lastname: Chagas-Lima
authors.forename: Katia C
authors.initials: KC
authors.lastname: Gondim
authors.forename: Eduardo C
authors.initials: EC
authors.lastname: Torres-Santos
authors.forename: Evelize
authors.initials: E
authors.lastname: Folly
authors.forename: Elvira M
authors.initials: EM
authors.lastname: Saraiva
authors.forename: Narcisa L
authors.initials: NL
authors.lastname: Cunha-E-Silva
authors.forename: Maurilio J
authors.initials: MJ
authors.lastname: Soares
authors.forename: Georgia C
authors.initials: GC
authors.lastname: Atella
mesh_terms: D000818:Animals; D002417:Cattle; D002788:Cholesterol Esters / Q000378:metabolism; D004705:Endocytosis / Q000502:physiology*; D004951:Esterification; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D006801:Humans; D007894:Leishmania mexicana / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D008075:Lipoproteins, HDL / Q000097:blood / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000097:blood / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D011973:Receptors, LDL / Q000378:metabolism*; D047392:beta-Cyclodextrins / Q000494:pharmacology
chemical_list: D002788:Cholesterol Esters; D005456:Fluorescent Dyes; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D008563:Membrane Lipids; D011973:Receptors, LDL; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D016650:Fluorescein-5-isothiocyanate