Extracellular vesicles of pathogenically different Giardia strains reveal differential proteomic content

MOYANO, SOFÍA; MUSSO, JULIANA; CAMERINI, SERENA; CASELLA, MARIA; TOUZ, MARÍA CAROLINA; LALLE, MARCO

Salta

Congreso; LV SAIB - XIV PABMB.; 2019

Extracellular vesicles (EVs) are small vesicles that operate as cargoes from cell to cell, carrying proteins and nucleic acids, and are involved in physiological and pathological processes. EVs are also emerging as a potential therapeutic tool for the treatment of infectious diseases. The anaerobic parasitic protozoan Giardia lamblia is the etiological agent of human giardiasis, a diarrheal disease with a worldwide distribution, higher prevalence in developing countries, and mainly affecting children. Human infection results in a wide range of clinical outcomes and is almost due to two Giardia genetic groups, namely assemblages A and B. Differences at a genomic level occur between and within assemblages, which account for variations in growth rate, infectivity, and pathogenicity. Since Giardia releases EVs, to elucidate if variation in EVs content can associate with differences in assemblage pathogenicity, we analyzed the protein content of EVs released by G. lamblia WB (assemblage A) and GS (assemblage B) isolates. EVs released by trophozoites in well-defined culture conditions were purified by differential ultracentrifugation (microvesicles and exosome fractions). EVs were morphologically and biochemically characterized by electron microscopy, dynamic light scattering (DLS), proteomic assays, and immunoblotting. Our results indicate that EVs with different sizes and shapes are produced by both Giardia isolates, although in different amounts. EVs proteome was characterized by high-resolution mass spectrometry, showing the presence of typical EVs markers as well as proteins unique to Giardia. Proteins exclusively associated with exosomes (endosomal origin) or microvesicles (plasma membrane origin) were also identified. Virulence factor candidates and assemblage-specific proteins were also present. Our results provide evidence that differences in the amount and content of EVs occur between assemblages A and B, pointing on their role in determining the difference in Giardia isolate pathogenicity and virulence.