Iron and contact with host cells induce expression of adhesins on surface of Trichomonas vaginalis

Abstract

SummaryThe proteins AP65, AP51, AP33 and AP23 synthesized by Trichomonas vaginalis organisms in high iron play a role in adherence. Multigene families encode enzymes of the hydrogenosome organelles, which have identity to adhesins. This fact raises questions regarding the compartmentalization of the proteins outside the organelle and about the interactions of adhesins with host cells. Data here demonstrate the presence of the proteins outside the organelle under high-iron conditions. Fluorescence and immunocytochemical experiments show that high-iron-grown organisms coexpressed adhesins on the surface and intracellularly in contrast with low-iron parasites. Furthermore, the AP65 epitopes seen by rabbit anti-AP65 serum that blocks adherence and detects surface proteins were identified, and a mAb reacting to those epitopes recognized the trichomonal surface. Twodimensional electrophoresis and immunoblot of adhesins from surface-labelled parasites provided evidence that all members of the multigene family were co-ordinately expressed and placed on the trichomonal surface. Similar two-dimensional analysis of proteins from purified hydrogenosomes obtained from iodinated trichomonads confirmed the specific surface labelling of proteins. Contact of trichomonads with vaginal epithelial cells increased the amount of surface-expressed adhesins. Moreover, we found a direct relationship between the levels of adherence and amount of adhesins bound to immortalized vaginal and ureter epithelial cells, further reinforcing specific associations. Finally, trichomonads of MR100, a drug-resistant isolate absent in hydrogenosome proteins and adhesins, were non-adherent. Overall, the results confirm an important role for iron and contact in the surface expression of adhesins of T. vaginalis organisms.

Trichomonas vaginalis perturbs the junctional complex in epithelial cells

“…Here, major effects were observed by scanning electron microscopy where large intercellular spaces were seen after parasite-cell interaction. Similar observations were previously tional complex of different cell lines takes place when they are submitted to several conditions, including removal of calcium [44][45][46]. Several other changes are associated with such disruption as (1) loss of membrane association of the junctional complex-associated proteins; (2) a loss of TJ strands, visualized in freeze-fracture replicas; (3) a decrease in the TER; and (4) a dramatic increase in transepithelial permeability to tracers.…”

tvcp12: a novel Trichomonas vaginalis cathepsin L-like cysteine proteinase-encoding gene

“…In addition, iron controls the expression of hydrogenosomal proteins such as pyruvate : ferredoxin oxidoreductase and ferredoxin (Gorrell, 1985), and virulence genes, such as those encoding some of the T. vaginalis adhesin proteins (Lehker et al, 1991;Engbring et al, 1996;Alderete et al, 1998;García et al, 2003). Tsai et al (2002) identified an iron-responsive promoter in the ap65-1 gene which could be involved in the transcriptional regulation of some of these genes.…”

Mechanisms ofTritrichomonas foetusPathogenicity in Cats with Insights from Venereal Trichomonosis

“…At least one bovine T. foetus and five functionally diverse T. vaginalis adhesin proteins, named on the basis of their molecular weights ( T. foetus : Tf190; T. vaginalis : AP120, AP65, AP51, AP33, AP23) have been identified 48, 49, 56, 57. A direct relationship exists between cellular adherence and the abundance of adhesin proteins that remain bound to vaginal epithelial and HeLa cell surfaces after interaction with trichomonads 49, 58, 59. Isolates devoid of adhesins or treated with antiadhesin antibodies become nonadherent 58.…”

“…Cysteine proteases mediate efficient adhesion of T. vaginalis to HeLa cells and vaginal epithelial cells in vitro 66. In bovine T. foetus , the role of cysteine proteases as adhesion proteins has not been investigated directly but is suggested by studies in a mouse model of venereal trichomonosis in which inhibition of trichomonad cysteine protease activity resulted in decreased genital colonization 58. At least 23 and 15 different cysteine proteases have been identified in T. vaginalis and bovine T. foetus , respectively 60, 67, 68, 69, 70.…”