Trichomonas vaginalis and Tritrichomonas foetus: interaction with fibroblasts and muscle cells - new insights into parasite-mediated host cell cytotoxicity

Abstract

Trichomonas vaginalis and Tritrichomonas foetus are parasitic, flagellated protists that inhabit the urogenital tract of humans and bovines, respectively. T. vaginalis causes the most prevalent non-viral sexually transmitted disease worldwide and has been associated with an increased risk for human immunodeficiency virus-1 infection in humans. Infections by T. foetus cause significant losses to the beef industry worldwide due to infertility and spontaneous abortion in cows. Several studies have shown a close association between trichomonads and the epithelium of the urogenital tract. However, little is known concerning the interaction of trichomonads with cells from deeper tissues, such as fibroblasts and muscle cells. Published parasite-host cell interaction studies have reported contradictory results regarding the ability of T. foetus and T. vaginalis to interact with and damage cells of different tissues. In this study, parasite-host cell interactions were examined by culturing primary human fibroblasts obtained from abdominal biopsies performed during plastic surgeries with trichomonads. In addition, mouse 3T3 fibroblasts, primary chick embryo myogenic cells and L6 muscle cells were also used as models of target cells. The parasite-host cell cultures were processed for scanning and transmission electron microscopy and were tested for cell viability and cell death. JC-1 staining, which measures mitochondrial membrane potential, was used to determine whether the parasites induced target cell damage. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labelling staining was used as an indicator of chromatin damage. The colorimetric crystal violet assay was performed to ana-lyse the cytotoxicity induced by the parasite. The results showed that T. foetus and T. vaginalis adhered to and were cytotoxic to both fibroblasts and muscle cells, indicating that trichomonas infection of the connective and muscle tissues is likely to occur; such infections could cause serious risks to the infected host

Hydrogenosome Metabolism Is the Key Target for Antiparasitic Activity of Resveratrol against Trichomonas vaginalis

“…JC-1 is a fluorescent lipophilic and cationic probe that can be used to determine the mitochondrial and hydrogenosomal ⌬m (28,66). Use of the JC-1 probe revealed that RESV and MDZ induced a loss of ⌬m, suggesting that these agents also produced a metabolic perturbation of the hydrogenosome.…”

“…The hydrogenosomal membrane potential (⌬m) of T. vaginalis was determined by using the JC-1 kit (Molecular Probes) with the cationic fluorescent probe 5,5=,6,6=-tetrachloro-1, 1=,3,3=-tetraethylbenzimidazolcarbocyanine iodide (JC-1). JC-1 can selectively enter hydrogenosomes and, according to the magnitude of the hydrogenosomal membrane potential, change its oligomeric state, thereby allowing it to fluoresce (28). The assay was carried out as follows: T. vaginalis trophozoites were suspended in culture medium (5 ϫ 10 5 trophozoites per 100 l) containing RESV (at concentrations of 0, 25, 50, and 100 mM) or MDZ (at concentrations of 0, 3.125, 6.25, and 12.5 mM) and incubated in 96-well cell culture plates for 2 h at 37°C in a container to which a vacuum was applied.…”

The biology of Trichomonas vaginalis in the light of urogenital tract infection

“…The parabasalian parasite is estimated to infect about 276 million new hosts annually worldwide [3], and in the US about 1 in 30 women tests positive for Trichomonas [4]. The parasite mainly affects the urogenital tract of both men and women, but it has also been isolated from the respiratory tract of infants [5] and adults [6] and a few in vitro studies have demonstrated that Trichomonas can attach to fibroblasts, muscle-and MDCK-cells [7,8]. Within the urogenital tract the parasite invades the squamous epithelium, which can not only lead to vaginitis/prostatitis, but also increase the risk of HIV transmission and the risk of low birth weights [9].…”

Unexplained Infertility Caused by a Latent but Serious Intruder: Trichomonas vaginalis?

“…Recently, trichomonas have been isolated from fallopian tubes, peritoneal fluid, and the pouch Douglas, suggesting that motile trichomonas may be able to invade the whole genital tract [32,33]. There are several studies that conclude that T. vaginalis causes urogenital damage to different types of cells and tissues, such as connective and muscular tissues, due to an excessive cytotoxic local effect suggesting high risk of reproductive failure [9,[33][34][35][36][37][38][39]. Trichomonas bind to the cells inducing membrane retraction, cell blebbing, and apoptosis.…”

“…Trichomonas bind to the cells inducing membrane retraction, cell blebbing, and apoptosis. These changes of cell architecture can be evidenced under microscopy and characterized by condensed chromatin and intense cytoplasm vacuolization [39].…”