Trypanosoma Cruzi G and Y Strains' Metacyclic Trypomastigote Sheds Extracellular Vesicles and Trigger Host-Cell Communication.

Abstract

Trypanosoma cruzi, a protozoan parasite, spontaneously releases extracellular vesicles (EVs) that facilitate communication with both invertebrate and vertebrate hosts. The results obtained by several groups indicated compositional variations in EVs generated by distinct types of T. cruzi. Nonetheless, few studies have characterized EVs derived from metacyclic trypomastigotes (MT), the form that develops in the vector and infects vertebrate hosts. This study aimed to characterize and compare EVs extracted from MTs of two T. cruzi parasite strains belonging to distinct groups with varying infectivity patterns. We examined the nature of these EVs and their influence on parasite-host interactions and host immune responses. Our findings demonstrated that EVs from G and Y strains showed no significant size differences; nonetheless, they exhibited variations in protein composition as shown by proteomic analysis, atomic force microscopy, and immunoenzymatic assays, including alterations in the presence of virulence factors. EVs from both strains interacted with and were taken up by human THP-1 monocytes, resulting in NF-κB activation. The EVs release from Y strain increase in the mRNA levels of RANTES, TNF-alpha, and IFN-beta, while inducing a similar nitric oxide (NO) increase relative to control cells. EVs from both strains also increased host cell invasion, however, EVs from the Y further increased the number of intracellular parasites. These results suggest that the infectivity of various strains by insect-derived forms correlates with EV secretion via the control of the host immune response, potentially leading to distinct infection patterns.