Ik-Hwan Han

Proinflammatory cytokine and nitric oxide production by human macrophages stimulated with Trichomonas vaginalis.

Trichomonas vaginalis commonly causes vaginitis and perhaps cervicitis in women and urethritis in men and women. Macrophages are important immune cells in response to T. vaginalis infection. In this study, we investigated whether human macrophages could be involved in inflammation induced by T. vaginalis. Human monocyte-derived macrophages (HMDM) were co-cultured with T. vaginalis. Live, opsonized-live trichomonads, and T. vaginalis lysates increased proinflammatory cytokines, such as TNF-alpha, IL-1beta, and IL-6 by HMDM. The involvement of nuclear factor (NF)-kappaB signaling pathway in cytokine production induced by T. vaginalis was confirmed by phosphorylation and nuclear translocation of p65 NF-kappaB. In addition, stimulation with live T. vaginalis induced marked augmentation of nitric oxide (NO) production and expression of inducible NO synthase (iNOS) levels in HMDM. However, trichomonad-induced NF-kappaB activation and TNF-alpha production in macrophages were significantly inhibited by inhibition of iNOS levels with L-NMMA (NO synthase inhibitor). Moreover, pretreatment with NF-kappaB inhibitors (PDTC or Bay11-7082) caused human macrophages to produce less TNF-alpha. These results suggest that T. vaginalis stimulates human macrophages to produce proinflammatory cytokines, such as IL-1, IL-6, and TNF-alpha, and NO. In particular, we showed that T. vaginalis induced TNF-alpha production in macrophages through NO-dependent activation of NF-kappaB, which might be closely involved in inflammation caused by T. vaginalis.

Involvement of mast cells in inflammation induced by Trichomonas vaginalis via crosstalk with vaginal epithelial cells

Vaginal epithelial cells (VECs) are thought to function as immune‐responsive cells in trichomoniasis, and mast cells have been detected in vaginal smears and the vaginal wall in trichomoniasis. It therefore seemed possible that the VEC‐trichomonad reaction might affect the activity of mast cells present in the lamina propria of the vaginal mucosa. In this study, we tested whether culture supernatants of VEC incubated with Trichomonas vaginalis (TCM) could stimulate mast cells. When VECs (MS74) were incubated with live trichomonads, IL‐8, IL‐6 and MCP‐1 expressions increased in the TCM, and mast cells (HMC‐1) and human neutrophils migrated more actively towards the TCM. Also, when the TCM was added to mast cells, β‐hexosaminidase and cytokines (IL‐8 and TNF‐α) expressions were increased. Moreover, the culture supernatant of mast cells incubated with TCM (M‐TCM) had more increased chemotactic activity for neutrophils than that of TCM. We conclude that inflammatory mediators made by VECs in response to activation by T. vaginalis activate and attract mast cells and then stimulate them to induce neutrophil migration. Our results indicate, for the first time, that VECs play a role in the infiltration of mast cells and neutrophils early in T. vaginalis infection.

Histamine and TNF-α release by rat peritoneal mast cells stimulated with Trichomonas vaginalis

Mast cells have been reported to be predominant in the vaginal smears of patients infected with T. vaginalis. In this study, we investigated whether T. vaginalis could induce mast cells to migrate and to produce TNF-α and histamine. Rat peritoneal mast cells (RPMC), a primary mast cell, were used for the study. T. vaginalis induced an increase in chemotactic migration of the mast cells toward excretory and secretory product (ESP) of T. vaginalis, and the mast cells activated with T. vaginalis showed an increased release of histamine and TNF-α. Therefore, mast cells may be involved in the inflammatory response caused by T. vaginalis.

Signalling pathways associated with IL-6 production and epithelial-mesenchymal transition induction in prostate epithelial cells stimulated with Trichomonas vaginalis.

Trichomonas vaginalis (Tv) has been found in patient tissue of benign prostatic hyperplasia (BPH), and suggested to cause chronic prostatitis. IL‐6 is known as one of the important factors of chronic inflammation in prostate cancer. Patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) had higher levels of IL‐6 in seminal plasma. Furthermore, inflammatory conditions induced by pathogen infections have been shown to promote epithelial–mesenchymal transition (EMT). Here, we investigated the signals involved in IL‐6 production by human prostate epithelial cells (PECs) stimulated with Tv and examined whether Tv induces EMT in PECs. We found that PECs stimulated with Tv increased the production of IL‐6, as well as the expression of TLR2, TLR4, MAPKs (p38, JNK, ERK), NF‐κB and JAK2/STAT3, and levels of ROS. Inhibition of TLR2 or TLR4 reduced IL‐6 production as well as expression of these other factors, and agents inhibiting ROS, MAPKs, NF‐κB and JAK reduced IL‐6 production. However, when PECs were stimulated with Tv, transcripts of mesenchymal cell markers increased, and epithelial cell markers decreased. In addition, the induction of EMT was suppressed by inhibitors of JAK or NF‐κB. These findings are the first evidence that Tv infection of prostate epithelial cells may induce EMT.

Trichomonas vaginalis induces IL-1β production in a human prostate epithelial cell line by activating the NLRP3 inflammasome via reactive oxygen species and potassium ion efflux

Trichomonas vaginalis is a sexually transmitted protozoan parasite that causes vaginitis in women, and urethritis and prostatitis in men. IL‐1β is synthesized as immature pro‐IL‐1β, which is cleaved by activated caspase‐1. Caspase‐1 is, in turn, activated by a multi‐protein complex known as an inflammasome. In this study, we investigated the inflammatory response of a prostate epithelial cell line (RWPE‐1) to T. vaginalis and, specifically, the capacity of T. vaginalis to activate the NLRP3 inflammasome.

Proliferation of prostate stromal cell induced by benign prostatic hyperplasia epithelial cell stimulated with Trichomonas vaginalis via crosstalk with mast cell.

Chronic inflammation has a role in the pathogenesis of benign prostatic hyperplasia (BPH) and prostate cancer. Mast cells have been detected in chronic inflammatory infiltrate of the prostate, and it is possible that the interaction between prostate epithelial cells and Trichomonas vaginalis influences the activity of mast cells in the prostate stroma. Activated mast cells might influence the biological functions of nearby tissues and cells. In this study, we investigated whether mast cells reacted with the culture supernatant of BPH epithelial cells infected with T. vaginalis may induce the proliferation of prostate stromal cells.

Interaction between Trichomonas vaginalis and the Prostate Epithelium

Most men infected with Trichomonas vaginalis are asymptomatic and can remain undiagnosed and untreated. This has been hypothesized to result in chronic persistent prostatic infection. Adhesion of the protozoan organisms to mucosal cells is considered a first and prerequisite step for T. vaginalis infection. Adhesion of T. vaginalis to prostate epithelial cells has not yet been observed; however, there are several reports about inflammation of prostate epithelial cells induced by T. vaginalis. The aim of this study was to investigate whether adhesion and cytotoxicity of T. vaginalis are involved in inflammation of prostate epithelial cells. When RWPE-1 cells were infected with T. vaginalis (1:0.4 or 1:4), adhesion of T. vaginalis continuously increased for 24 hr or 3 hr, respectively. The cytotoxicity of prostate epithelial cells infected with T. vaginalis (RWPE-1: T. vaginalis=1:0.4) increased at 9 hr; at an infection ratio of 1:4, cytotoxicity increased after 3 hr. When the RWPE-1 to T. vaginalis ratio was 1:0.4 or 1:4, production of IL-1β, IL-6, CCL2, and CXCL8 also increased. Epithelial-mesenchymal transition (EMT) was verified by measuring decreased E-cadherin and increased vimentin expression at 24 hr and 48 hr. Taken together, the results indicate that T. vaginalis adhered to prostate epithelial cells, causing cytotoxicity, pro-inflammatory cytokine production, and EMT. Our findings suggest for the first time that T. vaginalis may induce inflammation via adhesion to normal prostate epithelial cells.

Inflammatory response of a prostate stromal cell line induced by Trichomonas vaginalis.

While Trichomonas vaginalis, a cause of sexually transmitted infection, is known as a surface‐dwelling protozoa, trichomonads have been detected in prostatic tissue from benign prostatic hyperplasia and prostatitis by immunoperoxidase assay or PCR. However, the immune response of prostate stromal cells infected with T. vaginalis has not been investigated. Our objective was to investigate whether T. vaginalis could induce an inflammatory response in prostate stromal cells. Incubation of a human prostate stromal myofibroblast cells (WPMY‐1) with live T. vaginalis T016 increased expression of the inflammatory chemokines CXCL8 and CCL2. In addition, TLR4, ROS, MAPK and NF‐κB expression increased, while inhibitors of TLR4, ROS, MAPKs and NF‐κB reduced CXCL8 and CCL2 production. Medium conditioned by incubation of WPMY‐1 cells with T. vaginalis stimulated the migration of human neutrophils and monocytes (THP‐1 cells). We conclude that T. vaginalis increases CXCL8 and CCL2 production by human prostate stromal cells by activating TLR4, ROS, MAPKs and NF‐κB, and this in turn attracts neutrophils and monocytes and leads to an inflammatory response. This study is the first attempt to demonstrate an inflammatory reaction in prostate stromal cells caused by T. vaginalis.

Proliferation of prostate epithelia induced by IL-6 from stroma reacted with Trichomonas vaginalis.

Benign prostatic hyperplasia (BPH) is characterized by the proliferation of stromal and epithelial cell types in the prostate, and interactions between the two types of cells. We demonstrated previously that proliferation of prostate stromal cells was induced by BPH epithelial cells in response to Trichomonas vaginalis (Tv) infection via crosstalk with mast cells. In this study, we investigated whether IL‐6 released by the proliferating stromal cells in turn induce the BPH epithelial cells to multiply. When culture supernatants of the proliferating prostate stromal cells were added to BPH epithelial cells, the latter multiplied, and expression of cyclin D1, FGF2 and Bcl‐2 increased. Blocking the IL‐6 signalling pathway with anti‐IL‐6R antibody or JAK1/2 inhibitor inhibited the proliferation of the BPH epithelial cells and reduced the expression of IL‐6, IL‐6R and STAT3. Also, epithelial‐mesenchymal transition was detected in the proliferating BPH epithelial cells. In conclusion, IL‐6 released from proliferating prostate stromal cells induced by BPH epithelial cells infected with Tv in turn induces multiplication of the BPH epithelial cells. This result provides first evidence that the inflammatory microenvironment of prostate stromal cells resulting from Tv infection induces the proliferation of prostate epithelial cells by stromal‐epithelial interaction.