title: Trypanosoma cruzi: role of δ-amastin on extracellular amastigote cell invasion and differentiation.
abstract: Trypanosoma cruzi is a protozoan parasite that comprises different phylogenetic groups and is the causative agent of Chagas' disease. Different T. cruzi strains present differences in infectivity in in vitro and in vivo experimental models, which are likely related to the expression of different virulence factors. Amastin is a surface glycoprotein abundantly expressed on the intracellular mammalian amastigote form of the parasite. In this study, we showed that a highly infective strain (G strain) of extracellular amastigote (EA) invasive forms expressed reduced RNA levels of amastin compared to a less infective strain (CL). The treatment of HeLa cells with recombinant δ-amastin reduced infectivity of EA forms. However, the ectopic expression of δ-amastin accelerated amastigote differentiation into trypomastigotes. Corroborating the virulence behavior in association with amastin expression, the EAs overexpressing amastin were precociously and robustly observed in the liver of susceptible mouse strains (A/JUnib), whereas parasitemia was never detected in in vivo assays. This is the first report on the regulatory role of amastin in the course of both in vitro and in vivo T. cruzi infection.
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina-UNIFESP, São Paulo, São Paulo, Brazil.
authors.forename: Mário C
authors.initials: MC
authors.lastname: Cruz
authors.forename: Normanda
authors.initials: N
authors.lastname: Souza-Melo
authors.forename: Claudio Vieira
authors.initials: CV
authors.lastname: da Silva
authors.forename: Wanderson Duarte
authors.initials: WD
authors.lastname: Darocha
authors.forename: Diana
authors.initials: D
authors.lastname: Bahia
authors.forename: Patrícia R
authors.initials: PR
authors.lastname: Araújo
authors.forename: Santuza R
authors.initials: SR
authors.lastname: Teixeira
authors.forename: Renato A
authors.initials: RA
authors.lastname: Mortara
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D014355:Chagas Disease / Q000469:parasitology; D015870:Gene Expression; D006790:Host-Parasite Interactions; D006801:Humans; D008099:Liver / Q000469:parasitology; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D014349:Trypanosoma cruzi / Q000235:genetics* / Q000472:pathogenicity*
chemical_list: D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; C088681:amastin protein, Trypanosoma cruzi