Characterization of nuclease activity produced and shedded by Trypanosoma cruzi trypomastigotes

DRAGO SOFÍA BELÉN; ALI SANTORO GIANFRANCO; LEGUIZAMÓN MARÍA SUSANA; BURGOS JUAN MIGUEL

Mar del Plata

Congreso; XXXI Reunión anual Sociedad Argentina de Protozoología; 2019

In several pathogenic microorganisms, since bacteria to protozoos, production ofnucleases was described as a virulence factor that, among other functions, would allowthem to escape from Neutrophil-produced NETs (neutrophil extracellular traps), DNAtramps produced as part of the natural immune response. Recently, Trypanosoma cruzi,the etiological agent of Chagas disease, was observed to induce NETs where,interestingly, parasites persist alive.Herein we describe the production, shedding, and the first characterization of a nucleaseactivity by means of T. cruzi trypomastigotes (CL Brener strain). For these studies,cells-free parasites were incubated in CO 2 atmosphere from hours to several days andtheir supernatant was tested for nuclease activity. Through DNA degradation studies weobserved that nuclease shedding, and its activity, depends on incubation temperature.Moreover, nuclease activity was observed both on circular and lineal plasmid, as well ason human genomic DNA. By means of zymography approaches (SDS-PAGE withDNA from salmon testes), at least two proteins, of 40 and 55 kDa approximately, withnuclease activity were observed. Among cofactors, activity depends on Mg ++ presencebut not Ca ++ cations, and is inhibited by Zn ++ and EDTA. Moreover, it is no longerobserved in samples heated above 70ºC. Our observations describe, by the first time, theproduction and shedding of nuclease activity by T. cruzi trypomastigotes, which couldconstitute a new parasitic virulence factor. Protein purification and identification isunder process.