Extracellular vesicles and vesicle-free secretome of the protozoa acanthamoeba castellanii under homeostasis and nutritional stress and their damaging potential to host cells

Diego de Souza Gonçalves, Marina da Silva Ferreira, Susie Coutinho Liedke, Kamilla Xavier Gomes, Gabriel Afonso de Oliveira, Pedro Ernesto Lopes Leão, Gabriele Vargas Cesar, Sergio H. Seabra, Juliana Reis Cortines, Arturo Casadevall, Leonardo Nimrichter, Gilberto Barbosa Domont, Magno Rodrigues Junqueira, Jose Mauro Peralta, Allan J. Guimaraes

Research output: Contribution to journalArticle

Abstract

Acanthamoeba castellanii (Ac) are ubiquitously distributed in nature, and by contaminating medical devices such as heart valves and contact lenses, they cause a broad range of clinical presentations to humans. Although several molecules have been described to play a role in Ac pathogenesis, including parasite host-tissue invasion and escaping of host-defense, little information is available on their mechanisms of secretion. Herein, we describe the molecular components secreted by Ac, under different protein availability conditions to simulate host niches. Ac extracellular vesicles (EVs) were morphologically and biochemically characterized. Dynamic light scattering analysis of Ac EVs identified polydisperse populations, which correlated to electron microscopy measurements. Highperformance thin liquid chromatography of Ac EVs identified phospholipids, steryl-esters, sterol and free-fatty acid, the last two also characterized by GC-MS. Secretome composition (EVs and EVs-free supernatants) was also determined and proteins biological functions classified. In peptone-yeastglucose (PYG) medium, a total of 179 proteins were identified (21 common proteins, 89 exclusive of EVs and 69 in EVs-free supernatant). In glucose alone, 205 proteins were identified (134 in EVs, 14 common and 57 proteins in EVs-free supernatant). From those, stress response, oxidative and protein and amino acid metabolism proteins prevailed. Qualitative differences were observed on carbohydrate metabolism enzymes from Krebs cycle and pentose phosphate shunt. Serine proteases and metalloproteinases predominated. Analysis of the cytotoxicity of Ac EVs (upon uptake) and EVs-free supernatant to epithelial and glioblastoma cells revealed a dose-dependent effect. Therefore, the Ac secretome differs depending on nutrient conditions, and is also likely to vary during infection.

Original languageEnglish (US)
Pages (from-to)818-836
Number of pages19
JournalVirulence
Volume9
Issue number1
DOIs
StatePublished - Jan 1 2018

Keywords

  • Acanthamoeba castellanii
  • Exosomes
  • Pathogenesis
  • Secretome
  • Virulence factors

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Microbiology (medical)
  • Infectious Diseases

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    de Souza Gonçalves, D., da Silva Ferreira, M., Liedke, S. C., Gomes, K. X., de Oliveira, G. A., Leão, P. E. L., Cesar, G. V., Seabra, S. H., Cortines, J. R., Casadevall, A., Nimrichter, L., Domont, G. B., Junqueira, M. R., Peralta, J. M., & Guimaraes, A. J. (2018). Extracellular vesicles and vesicle-free secretome of the protozoa acanthamoeba castellanii under homeostasis and nutritional stress and their damaging potential to host cells. Virulence, 9(1), 818-836. https://doi.org/10.1080/21505594.2018.1451184