Changes in cell-surface carbohydrates of Trypanosoma cruzi during metacyclogenesis under chemically defined conditions

Abstract

Highly purified lectins with specificities for receptor molecules containing sialic acid, N-acetylglucosamine (DGlcNAc), N-acetylgalactosamine (D-GalNAc), galactose (D-Gal), mannose-like residues (D-Man) or L-fucose (LFuc), were used to determine changes in cell-surface carbohydrates of the protozoal parasite Trypanosomu cruzi during metacyclogenesis under chemically defined conditions. Of the D-GalNAc-binding lectins, BS-I selectively agglutinated metacyclic trypomastigotes, MPL was selective for replicating epimastigotes, whereas SBA strongly agglutinated all developmental stages of T. cruzi. WGA (sialic acid and/or D-GIcNAc specific) was also reactive with differentiating epimastigotes and metacyclic trypomastigotes but displayed a higher reactivity with replicating epimastigote forms. A progressive decrease in agglutinating activity was observed for jacaline (specific for D-Gal) during the metacyclogenesis process; conversely, a progressive increase in affinity was observed for RCA-I (D-Gabspecific), although the reactivity of other D-Gal-specific lectins (PNA and AxP) was strong at all developmental stages. All developmental stages of T. cruzi were agglutinated by Con A and Lens cufinaris lectins (specific for D-Man-like residues); however, they were unreactive with the L-fucose-binding lectins from Lotus tetrugonolobos and Ufex europueus. These agglutination assays were further confirmed by binding studies using I z51-labelled lectins. Neuraminidase activity was detected in supernatants of cell-free differentiation medium using the PNA hemagglutination test with human A erythrocytes. The most pronounced differences in lectin agglutination activity were observed between replicating and differentiating epimastigotes, suggesting that changes in the composition of accessible cell-surface carbohydrates precede the morphological transformation of epimastigotes into metacyclic trypomastigotes.

Changes of sialomolecules during the dimethylsulfoxide-induced differentiation of Herpetomonas samuelpessoai

“…In the protozoan parasite Trypanosoma cruzi, previous studies using highly purified lectins with specificity for receptor molecules containing sialic acid identified changes in the cell surface content of this carbohydrate during metacyclogenesis (Andrade et al 1991). In this model, sialic-acidbinding lectins were reactive with differentiating epimastigotes and metacyclic trypomastigotes but displayed a higher reactivity with replicating epimastigote forms.…”

In vitro effects of citral on Trypanosoma cruzi metacyclogenesis

“…Trypomastigotes were more susceptible to citral than epimastigotes and bloodstream trypomastigotes were more susceptible to citral than in vitro-derived metacyclic trypomastigotes. Because epimastigotes, bloodstream trypomastigotes and metacyclic trypomastigotes have different metabolisms and different glycoconjugate compositions at the cell membrane (de Andrade et al 1991, de Souza 2008, these different susceptibilities could be due to different cell permeability rates for citral or different cellular targets.…”

A Novel IFN Regulatory Factor 3-Dependent Pathway Activated by Trypanosomes Triggers IFN-β in Macrophages and Fibroblasts

“…We demonstrate that the induction of ifnb is stage specific, as the epimastigote stage of the parasite does not induce this response, suggesting that the ligand that triggers the IFN response is differentially expressed within the parasite life cycle. Based on evidence that epimastigotes significantly differ from trypomastigotes with regard to the lipid (43), carbohydrate (44), and protein (45–47) composition of their surface coats, it is not surprising that the host response to these parasite life cycle stages would differ. Additionally, we demonstrate that T. cruzi -mediated induction of IFN- β mRNA results in a functional type I IFN response, leading to expression of the ISGs cxcl10 , viperin , and lrg47 , in fibroblasts and macrophages.…”