title: Proteomic analysis of Trypanosoma cruzi secretome: characterization of two populations of extracellular vesicles and soluble proteins.
abstract: Microorganisms use specialized systems to export virulence factors into host cells. Secretion of effector proteins into the extracellular environment has been described in Trypanosoma cruzi; however, a comprehensive proteomic analysis of the secretome and the secretion mechanisms involved remain elusive. Here, we present evidence that T. cruzi releases proteins associated with vesicles that are formed by at least two different mechanisms. Transmission electron microscopy showed larger vesicles budding from the plasma membrane of noninfective epimastigotes and infective metacyclic trypomastigotes, as well as smaller vesicles within the flagellar pocket of both forms. Parasite conditioned culture supernatant was fractionated and characterized by morphological, immunochemical, and proteomic analyses. Three fractions were obtained by differential ultracentrifugation: the first enriched in larger vesicles resembling ectosomes, the second enriched in smaller vesicles resembling exosomes, and a third fraction enriched in soluble proteins not associated with extracellular vesicles. Label-free quantitative proteomic analysis revealed a rich collection of proteins involved in metabolism, signaling, nucleic acid binding, and parasite survival and virulence. These findings support the notion that T. cruzi uses different secretion pathways to excrete/secrete proteins. Moreover, our results suggest that metacyclic forms may use extracellular vesicles to deliver cargo into host cells.
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo, SP 04023-062, Brazil.
authors.forename: Ethel
authors.initials: E
authors.lastname: Bayer-Santos
authors.forename: Clemente
authors.initials: C
authors.lastname: Aguilar-Bonavides
authors.forename: Silas Pessini
authors.initials: SP
authors.lastname: Rodrigues
authors.forename: Esteban Maurício
authors.initials: EM
authors.lastname: Cordero
authors.forename: Alexandre Ferreira
authors.initials: AF
authors.lastname: Marques
authors.forename: Armando
authors.initials: A
authors.lastname: Varela-Ramirez
authors.forename: Hyungwon
authors.initials: H
authors.lastname: Choi
authors.forename: Nobuko
authors.initials: N
authors.lastname: Yoshida
authors.forename: José Franco
authors.initials: JF
authors.lastname: da Silveira
authors.forename: Igor C
authors.initials: IC
authors.lastname: Almeida
mesh_terms: D000818:Animals; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D002853:Chromatography, Liquid; D017077:Culture Media, Conditioned / Q000737:chemistry; D005407:Flagella / Q000378:metabolism*; D008018:Life Cycle Stages / Q000502:physiology*; D051379:Mice; D046529:Microscopy, Electron, Transmission; D040901:Proteomics; D015800:Protozoan Proteins / Q000302:isolation & purification* / Q000378:metabolism; D022142:Secretory Vesicles; D053719:Tandem Mass Spectrometry; D014349:Trypanosoma cruzi / Q000502:physiology*; D014461:Ultracentrifugation; D037521:Virulence Factors / Q000302:isolation & purification*
chemical_list: D017077:Culture Media, Conditioned; D015800:Protozoan Proteins; D037521:Virulence Factors