CONICET | Buscador de Institutos y Recursos Humanos

Characterization of nuclease activity produced and shedding by T. cruzi trypomastigotes Neutrophil-produced NETs (neutrophil extracellular traps) is part of the natural immune response against pathogenic microorganisms. In them, production of nucleases was described as a virulence factor that, among other functions, would allow them to escape from DNA nets. 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 first characterization of a nuclease activity by means of T. cruzi CL Brener trypomastigotes. For these studies, cells-free parasites were incubated in CO2 atmosphere from hours to several days and supernatant was tested for nuclease activity. Through DNA degradation studies we observed that shedding depends on incubation temperature, as well as the enzyme activity, that was observed on circular and linear plasmid as well as on genomic DNA. By means of zymography approaches at least two proteins, of 40 and 55 kDa approximately, with nuclease activity were observed. Among cofactors, nuclease activity depends on Mg++ presence but not Ca++ cations, and is inhibited by Zn++ and EDTA. Moreover, the nuclease activity is no longer observed in samples heated above 70ºC. Our observations describe, by the first time, the production and shedding of nuclease activity by T. cruzi trypomastigotes, which could constitute a new parasitic virulence factor. Protein purification and identification is under process.