title: Simultaneous gene expression profiling in human macrophages infected with Leishmania major parasites using SAGE.
abstract: BACKGROUND
  Leishmania (L) are intracellular protozoan parasites that are able to survive and replicate within the harsh and potentially hostile phagolysosomal environment of mammalian mononuclear phagocytes. A complex interplay then takes place between the macrophage (MPhi) striving to eliminate the pathogen and the parasite struggling for its own survival. To investigate this host-parasite conflict at the transcriptional level, in the context of monocyte-derived human MPhis (MDM) infection by L. major metacyclic promastigotes, the quantitative technique of serial analysis of gene expression (SAGE) was used.
  
  
  RESULTS
  After extracting mRNA from resting human MPhis, Leishmania-infected human MPhis and L. major parasites, three SAGE libraries were constructed and sequenced generating up to 28,173; 57,514 and 33,906 tags respectively (corresponding to 12,946; 23,442 and 9,530 unique tags). Using computational data analysis and direct comparison to 357,888 publicly available experimental human tags, the parasite and the host cell transcriptomes were then simultaneously characterized from the mixed cellular extract, confidently discriminating host from parasite transcripts. This procedure led us to reliably assign 3,814 tags to MPhis' and 3,666 tags to L. major parasites transcripts. We focused on these, showing significant changes in their expression that are likely to be relevant to the pathogenesis of parasite infection: (i) human MPhis genes, belonging to key immune response proteins (e.g., IFNgamma pathway, S100 and chemokine families) and (ii) a group of Leishmania genes showing a preferential expression at the parasite's intra-cellular developing stage.
  
  
  CONCLUSIONS
  Dual SAGE transcriptome analysis provided a useful, powerful and accurate approach to discriminating genes of human or parasitic origin in Leishmania-infected human MPhis. The findings presented in this work suggest that the Leishmania parasite modulates key transcripts in human MPhis that may be beneficial for its establishment and survival. Furthermore, these results provide an overview of gene expression at two developmental stages of the parasite, namely metacyclic promastigotes and intracellular amastigotes and indicate a broad difference between their transcriptomic profiles. Finally, our reported set of expressed genes will be useful in future rounds of data mining and gene annotation.
authors.affiliation: Laboratoire d'Immuno-Pathologie, Vaccinologie et Génétique Moléculaire, WHO Collaborating Center for Research and Training in Leishmaniasis, Institut Pasteur de Tunis, 13 place Pasteur, BP 74, 1002 Tunis-Belvédère, Tunisia. fzguerfali@yahoo.fr
authors.forename: Fatma Z
authors.initials: FZ
authors.lastname: Guerfali
authors.forename: Dhafer
authors.initials: D
authors.lastname: Laouini
authors.forename: Lamia
authors.initials: L
authors.lastname: Guizani-Tabbane
authors.forename: Florence
authors.initials: F
authors.lastname: Ottones
authors.forename: Khadija
authors.initials: K
authors.lastname: Ben-Aissa
authors.forename: Alia
authors.initials: A
authors.lastname: Benkahla
authors.forename: Laurent
authors.initials: L
authors.lastname: Manchon
authors.forename: David
authors.initials: D
authors.lastname: Piquemal
authors.forename: Sondos
authors.initials: S
authors.lastname: Smandi
authors.forename: Ons
authors.initials: O
authors.lastname: Mghirbi
authors.forename: Thérèse
authors.initials: T
authors.lastname: Commes
authors.forename: Jacques
authors.initials: J
authors.lastname: Marti
authors.forename: Koussay
authors.initials: K
authors.lastname: Dellagi
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D001483:Base Sequence; D018925:Chemokines / Q000235:genetics; D005110:Extracellular Space / Q000469:parasitology; D020869:Gene Expression Profiling / Q000379:methods*; D005786:Gene Expression Regulation; D015723:Gene Library; D005805:Genes, MHC Class I; D005802:Genes, MHC Class II; D006790:Host-Parasite Interactions / Q000235:genetics*; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics; D042541:Intracellular Space / Q000469:parasitology; D018320:Leishmania major / Q000235:genetics* / Q000502:physiology; D016773:Leishmaniasis, Cutaneous / Q000235:genetics* / Q000469:parasitology*; D008264:Macrophages / Q000378:metabolism* / Q000469:parasitology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D009418:S100 Proteins / Q000235:genetics
chemical_list: D018925:Chemokines; D012333:RNA, Messenger; D009418:S100 Proteins; D007371:Interferon-gamma