title: Antisense phosphorothioate oligonucleotides: selective killing of the intracellular parasite Leishmania amazonensis.
abstract: We targeted the mini-exon sequence, present at the 5' end of every mRNA of the protozoan parasite Leishmania amazonensis, by phosphorothioate oligonucleotides. A complementary 16-mer (16PS) was able to kill amastigotes--the intracellular stage of the parasite--in murine macrophages in culture. After 24 hr of incubation with 10 microM 16PS, about 30% infected macrophages were cured. The oligomer 16PS acted through antisense hybridization in a sequence-dependent way; no effect on parasites was observed with noncomplementary phosphorothioate oligonucleotides. The antisense oligonucleotide 16PS was a selective killer of the protozoans without any detrimental effect to the host macrophage. Using 16PS linked to a palmitate chain, which enabled it to complex with low density lipoproteins, improved the leishmanicidal efficiency on intracellular amastigotes, probably due to increased endocytosis. Phosphorothioate oligonucleotides complementary to the intron part of the mini-exon pre-RNA were also effective, suggesting that antisense oligomers could prevent trans-splicing in these parasites.
authors.affiliation: Laboratoire de Biophysique Moléculaire Institut National de la Santé et de la Recherche Médicale Unité 386, Université de Bordeaux II, France.
authors.forename: C
authors.initials: C
authors.lastname: Ramazeilles
authors.forename: R K
authors.initials: RK
authors.lastname: Mishra
authors.forename: S
authors.initials: S
authors.lastname: Moreau
authors.forename: E
authors.initials: E
authors.lastname: Pascolo
authors.forename: J J
authors.initials: JJ
authors.lastname: Toulmé
mesh_terms: D000818:Animals; D000981:Antiprotozoal Agents / Q000008:administration & dosage / Q000633:toxicity*; D001483:Base Sequence; D002478:Cells, Cultured; D004337:Drug Carriers; D005091:Exons; D007438:Introns; D007894:Leishmania mexicana / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D008077:Lipoproteins, LDL; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000469:parasitology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage / Q000633:toxicity*; D014176:Protein Biosynthesis / Q000187:drug effects; D012326:RNA Splicing / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics; D013873:Thionucleotides / Q000633:toxicity*
chemical_list: D000981:Antiprotozoal Agents; D004337:Drug Carriers; D008077:Lipoproteins, LDL; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D013873:Thionucleotides