Induction of TLR5, IRAK1, and NF-κB expression by Trichomonas vaginalis in cervical cancer cell (HeLa) and normal human vaginal epithelial cell (HVECs) lines

Abstract

Introduction: Trichomoniasis is the most common non-viral sexually transmitted infection that increases the risk of cervical cancer. Trichomonas vaginalis (T. vaginalis) can regulate the pro-inflammatory cytokine production in the host cells. Toll-like receptors (TLRs) are a family of the pattern recognition receptors (PRRs) of mammalian cells, expressed in various host cells and have an important role in recognizing pathogens, and pro-inflammatory responses. The aim of the present study is to investigate the role of TLR5 in cervical cancer cells (HeLa) and human vaginal epithelial cells (HVECs) exposed to T. vaginalis.

Methodology: First, the cells and parasites were cultured in RPMI and trypticase yeast extract maltose (TYM), respectively. After adaption of parasite and epithelial cells by RPMI-TYM medium co-culture (9:1 vol/vol), HVECs and HeLa cells were stimulated with T. vaginalis trophozoites (24-hour incubation at 37 °C, 5% CO2). Following RNA extraction and cDNA synthesis, the gene expression levels of TLR5, IRAK1, and NF-κB were assessed using real-time PCR. Besides, the protein levels were measured using western blotting. All tests and controls were normalized using β-actin as a housekeeping control.

Results: Real-time PCR results showed an increased gene expression of TLR5, IRAK1, and NF-κB in T. vaginalis exposed HVECs and HeLa cells compared to the control group (p < 0.05). Additionally, western blot analysis showed a statistically significant increase in TLR5, and NF-κB proteins in both groups after exposure to the parasite (p < 0.05).

Conclusions: These findings provide insight into the host-parasite interaction, and the results indicated that T. vaginalis could stimulate TLR5 and activate related pathways.

Keywords: Human vaginal epithelial cell; TLR5; in vitro; inflammation; trichomoniasis.