Expression of Toll-like receptors (TLR) and responsiveness to TLR agonists by polarized mouse uterine epithelial cells in culture

Ovarian sex steroid and epithelial control of immune responses in the uterus and oviduct: human and animal models†

The female reproductive tract (FRT), including the uterus and oviduct (Fallopian tube), is responsible for maintaining an optimal microenvironment for reproductive processes, such as gamete activation and transportation, sperm capacitation, fertilization, and early embryonic and fetal development. The mucosal surface of the FRT may be exposed to pathogens and sexually transmitted microorganisms due to the opening of the cervix during mating. Pathogens and endotoxins may also reach the oviduct through the peritoneal fluid. To maintain an optimum reproductive environment while recognizing and killing pathogenic bacterial and viral agents, the oviduct and uterus should be equipped with an efficient and rigorously controlled immune system. Ovarian sex steroids can affect epithelial cells and underlying stromal cells, which have been shown to mediate innate and adaptive immune responses. This, in turn, protects against potential infections while maintaining an optimal milieu for reproductive events, highlighting the homeostatic involvement of ovarian sex steroids and reproductive epithelial cells. This article will discuss how ovarian sex steroids affect the immune reactions elicited by the epithelial cells of the non-pregnant uterus and oviduct in the bovine, murine, and human species. Finally, we propose that there are regional and species-specific differences in the immune responses in FRT.

Reduced Bioactive Microbial Products (Pathogen-Associated Molecular Patterns) Contribute to Dysregulated Immune Responses and Impaired Healing in Infected Wounds in Mice with Diabetes

Diabetic chronic ulcers are plagued with persistent nonresolving inflammation. However, diabetic wound environment early after injury suffers from inadequate inflammatory responses due to reductions in proinflammatory cytokines levels. Diabetic neutrophils have known impairments in bactericidal functions. We hypothesized that reduced bacterial killing by diabetic neutrophils, due to their bactericidal functional impairments, results in reduced bioactive bacterial products, known as pathogen-associated molecular patterns, which in turn contribute to reduced signaling through toll-like receptors, leading to inadequate production of proinflammatory cytokines in infected diabetic wound early after injury. We tested our hypothesis in db/db type 2 obese diabetic mouse wound infection model with Pseudomonas aeruginosa. Our data indicate that despite substantially higher levels of infection, toll-like receptor 4-mediated signaling is reduced in diabetic wounds early after injury owing to reduced bioactive levels of lipopolysaccharide. We further demonstrate that topical treatment with lipopolysaccharide enhances toll-like receptor 4 signaling, increases proinflammatory cytokine production, restores leukocyte trafficking, reduces infection burden, and stimulates healing in diabetic wounds. We posit that lipopolysaccharide may be a viable therapeutic option for the treatment of diabetic foot ulcers if it is applied topically after the surgical debridement process, which is intended to reset chronic ulcers into acute fresh wounds.

Progesterone differentially affects the transcriptomic profiles of cow endometrial cell types

Background

The endometrium is a heterogeneous tissue composed of luminal epithelial (LE), glandular epithelial (GE), and stromal cells (ST), experiencing progesterone regulated dynamic changes during the estrous cycle. In the cow, this regulation at the transcriptomic level was only evaluated in the whole tissue. This study describes specific gene expression in the three types of cells isolated from endometrial biopsies following laser capture microdissection and the transcriptome changes induced by progesterone in GE and ST cells.

Results

Endometrial LE, GE, and ST cells show specific transcriptomic profiles. Most of the differentially expressed genes (DEGs) in response to progesterone are cell type-specific (96%). Genes involved in cell cycle and nuclear division are under-expressed in the presence of progesterone in GE, highlighting the anti-proliferative action of progesterone in epithelial cells. Elevated progesterone concentrations are also associated with the under-expression of estrogen receptor 1 (ESR1) in GE and oxytocin receptor (OXTR) in GE and ST cells. In ST cells, transcription factors such as SOX17 and FOXA2, known to regulate uterine epithelial-stromal cross-talk conveying to endometrial receptivity, are over-expressed under progesterone influence.

Conclusions

The results from this study show that progesterone regulates endometrial function in a cell type-specific way, which is independent of the expression of its main receptor PGR. These novel insights into uterine physiology present the cell compartment as the physiological unit rather than the whole tissue.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08323-z.

Insights into the toll-like receptors in sexually transmitted infections

Toll-like receptors (TLRs) are like soldiers of an innate immune system, which protects vital biological processes against invading pathogens. TLR signalling pathways help in the removal of pathogens and mediate well-established inflammatory processes. However, these processes may also aid in the development or augmentation of an infection or an autoimmune disease. Recent studies have delineated TLR polymorphism's role in the loss of function, making hosts more resistant or vulnerable to the development of an infection. In this review, we have discussed the association of TLRs with sexually transmitted infections (STIs), especially to the pathogen-specific ligands. We have also assessed the impact on TLR downstream signalling and the maintenance of cellular homeostasis during immune responses. Besides, we have discussed the role of TLRs single nucleotide polymorphisms in various STIs. Since TLRs are known to play a part in defence mechanisms and in aiding infections therefore, a thorough understanding of TLRs structure and molecular mechanisms is required to explain how they can influence the outcome of an STI. Such a strategy may lead to the development of novel and useful immunotherapeutic approaches to control pathogen progression and prevent transmission.

Assessment of Immunological Response and Impacts on Fertility Following Intrauterine Vaccination Delivered to Swine in an Artificial Insemination Dose

To protect the health of sows and gilts, significant investments are directed toward the development of vaccines against infectious agents that impact reproduction. We developed an intrauterine vaccine that can be delivered with semen during artificial insemination to induce mucosal immunity in the reproductive tract. An in vitro culture of uterine epithelial cells was used to select an adjuvant combination capable of recruiting antigen-presenting cells into the uterus. Adjuvant polyinosinic:polycytidylic acid (poly I:C), alone or in combination, induced expression of interferon gamma, tumor necrosis factor alpha, and select chemokines. A combination adjuvant consisting of poly I:C, host defense peptide and polyphosphazene (Triple Adjuvant; TriAdj), which previously was shown to induce robust mucosal and systemic humoral immunity when administered to the uterus in rabbits, was combined with boar semen to evaluate changes in localized gene expression and cellular recruitment, in vivo. Sows bred with semen plus TriAdj had decreased γδ T cells and monocytes in blood, however, no corresponding increase in the number of monocytes and macrophages was detected in the endometrium. Compared to sows bred with semen alone, sows bred with semen plus TriAdj showed increased CCL2 gene expression in the epithelial layer. These data suggest that the adjuvants may further augment a local immune response and, therefore, may be suitable for use in an intrauterine vaccine. When inactivated porcine parvovirus (PPV) formulated with the TriAdj was administered to the pig uterus during estrus along with semen, we observed induction of PPV antibodies in serum but only when the pigs were already primed with parenteral PPV vaccines. Recombinant protein vaccines and inactivated PPV vaccines administered to the pig uterus during breeding as a primary vaccine alone failed to induce significant humoral immunity. More trials need to be performed to clarify whether repeated intrauterine vaccination can trigger strong humoral immunity or whether the primary vaccine needs to be administered via a systemic route to promote a mucosal and systemic immune response.

The Female Response to Seminal Fluid

Seminal fluid is often assumed to have just one function in mammalian reproduction, delivering sperm to fertilize oocytes. But seminal fluid also transmits signaling agents that interact with female reproductive tissues to facilitate conception and .pregnancy. Upon seminal fluid contact, female tissues initiate a controlled inflammatory response that affects several aspects of reproductive function to ultimately maximize the chances of a male producing healthy offspring. This effect is best characterized in mice, where the female response involves several steps. Initially, seminal fluid factors cause leukocytes to infiltrate the female reproductive tract, and to selectively target and eliminate excess sperm. Other signals stimulate ovulation, induce an altered transcriptional program in female tract tissues that modulates embryo developmental programming, and initiate immune adaptations to promote receptivity to implantation and placental development. A key result is expansion of the pool of regulatory T cells that assist implantation by suppressing inflammation, mediating tolerance to male transplantation antigens, and promoting uterine vascular adaptation and placental development. Principal signaling agents in seminal fluid include prostaglandins and transforming growth factor-β. The balance of male signals affects the nature of the female response, providing a mechanism of ‟cryptic female choiceˮ that influences female reproductive investment. Male-female seminal fluid signaling is evident in all mammalian species investigated including human, and effects of seminal fluid in invertebrates indicate evolutionarily conserved mechanisms. Understanding the female response to seminal fluid will shed new light on infertility and pregnancy disorders and is critical to defining how events at conception influence offspring health.

Mechanism of penehyclidine hydrochloride on a dysmenorrhea rat model

Primary dysmenorrhea affects the quality of life in young women, particularly school and work performance. This study investigated the mechanisms of penehyclidine hydrochloride (PHC) efficacy on a rat model of primary dysmenorrhea. The model was induced by injecting both estradiol benzoate and oxytocin. Different doses of PHC were administrated intraperitoneally following estradiol benzoate administration. Writhing scores were assessed, and pathological changes of the uterus were observed via hematoxylin and eosin staining. Western blot and real-time PCR were used to evaluate the expression level of the M₃ receptor, both TLR₃ and TLR₄ in uterine tissue, and the level of Ca²⁺ was measured in uterine tissues. Writhing scores significantly decreased in the PHC treatment group compared to model, and PHC alleviated the occurrence of edema or necrosis in the uteri compared to model group. PHC can decrease the M₃ receptor, TLR₃ , TLR₄ expression, and the Ca²⁺ level compared to the model group. PHC is a potential candidate for the future treatment of primary dysmenorrhea due to its ability to attenuate muscarinic receptors and TLRs. Preclinical Research & Development.

Analysis of stage-specific expression of the toll-like receptor family in the porcine endometrium throughout the estrous cycle and pregnancy

Toll-like receptors (TLRs) play critical roles in innate immunity by regulating antimicrobial responses in mucosal tissues. The expression and function of TLRs in female reproductive tissues have been studied in several species, but the expression and function of TLRs and MYD88, an adaptor molecule in the TLR signaling pathway, at the maternal-conceptus interface are not well understood in pigs. Thus, we determined the expression of TLR1 - TLR10 and MYD88 in the endometrium, conceptus, and chorioallantoic tissues of pigs. TLR1 - TLR10 and MYD88 mRNAs were expressed in the endometrium during the estrous cycle and pregnancy in a stage-dependent manner. TLR and MYD88 mRNAs were also detected in early stage conceptuses and chorioallantoic tissues from Day 30 to term pregnancy. The expression of TLR2, TLR4, TLR5, and TLR7 was localized to epithelial and stromal cells in endometrial and chorioallantoic tissues. Increasing doses of P₄, but not E₂, induced the expression of TLR4, TLR5, TLR6, TLR7, and TLR8, while interferon-γ increased the expression of TLR2 and TLR7 in endometrial explant tissues. Expression of TLR3, TLR5, TLR6, TLR7, and MYD88 was higher in the endometrium with somatic cell nucleus transfer-derived conceptuses than conceptuses derived from natural mating on Day 12. These results indicate that the expression of TLR1 - TLR10 and MYD88 is dynamically regulated at the maternal-conceptus interface in pigs, suggesting that TLRs expressed in the endometrium and the placenta may play a critical role in regulating mucosal immune responses to support the establishment and maintenance of pregnancy.

Expression of pattern recognition receptors in porcine uterine epithelial cells in vivo and in culture

Preservation of a pathogen free uterine environment is critical for maintaining healthy swine herds with high reproductive performance. Considering that uterine epithelial cells are the most numerous and thus likely point of cellular contact for pathogens in the uterus, we hypothesize that these cells may be critical for activating the immune system to clear uterine infections. Although uterine epithelial cells have not been well characterized in pigs, studies in several other species have shown that these cells express several pattern recognition receptors (PRR) and thus may act as sentinels for the uterine immune response. To characterize PRR expression in the porcine uterine epithelia, we used laser-capture microdissection to isolate epithelial cells lining the porcine uterus to quantify in vivo mRNA expression levels for select PRRs. As well, primary uterine epithelial cells (UECs) were isolated, cultured, polarized and PRR expression was quantified. Immunohistofluorescence and immunofluorescence were used to determine subcellular localization of TLR3, TLR4 and TLR9 in both uterine tissue and in polarized primary UECs. Finally, polarized primary UECs were stimulated with ligands for TLR3, TLR4, TLR9 and NOD2 to determine their functional innate immune response. Uterine epithelial cells (in vivo and in vitro) were shown to express TLR1-7, TLR9, NOD1, NOD2, NLRP3, NLRP6, NLRX1, RIG1, MDA5 and LGP2. Subcellular localization of in vivo and polarized primary UECs exhibited TLR3 and TLR9 localized to the apical cell surface whereas TLR4 was localized to the intracellular space. Polarized primary UECs stimulated with TLR3, TLR4 and TLR9 ligands showed induced secretion of IL-6, IL-13 and IL-10, respectively indicating that these receptors were functional. These results indicate that pig uterine epithelial cells are functional innate immune cells that may act as sentinels to protect against uterine infection.

Innate immunity and the sensing of infection, damage and danger in the female genital tract

Tissue homeostasis in the female genital tract is challenged by infection, damage, and even physiological events during reproductive cycles. We propose that the evolutionarily ancient system of innate immunity is sufficient to sense and respond to danger in the non-pregnant female genital tract. Innate immunity produces a rapidly inducible, non-specific response when cells sense danger. Here we provide a primer on innate immunity and discuss what is known about how danger signals are sensed in the endometrium and ovary, the impact of inflammatory responses on reproduction, and how endocrinology and innate immunity are integrated. Endometrial epithelial and stromal cells, and ovarian granulosa cells express pattern recognition receptors, similar to cells of the innate immune system. These pattern recognition receptors, such as the Toll-like receptors, bind pathogen-associated or damage-associated molecular patterns. Activation of pattern recognition receptors leads to inflammation, recruitment of immune cells from the peripheral circulation, and phagocytosis. Although the inflammatory response helps maintain or restore endometrial health, there may also be negative consequences for fertility, including perturbation of oocyte competence. The intensity of the inflammatory response reflects the balance between the level of danger and the systems that regulate innate immunity, including the endocrine environment. Understanding innate immunity is important because disease and inappropriate inflammatory responses in the endometrium or ovary cause infertility.

Endometrial microbiome at the time of embryo transfer: next-generation sequencing of the 16S ribosomal subunit

PURPOSE

Characterization of the human microbiome has become more precise with the application of powerful molecular tools utilizing the unique 16S ribosomal subunit's hypervariable regions to greatly increase sensitivity. The microbiome of the lower genital tract can prognosticate obstetrical outcome while the upper reproductive tract remains poorly characterized. Here, the endometrial microbiome at the time of single embryo transfer (SET) is characterized by reproductive outcome.

METHODS

Consecutive patients undergoing euploid, SET was included in the analysis. After embryo transfer, performed as per routine, the most distal 5-mm portion of the transfer catheter was sterilely placed in a DNA free PCR tube. Next-generation sequencing of the bacteria specific 16S ribosome gene was performed, allowing genus and species calls for microorganisms.

RESULTS

Taxonomy assignments were made on 35 samples from 33 patients and 2 Escherichia coli controls. Of the 33 patients, 18 had ongoing pregnancies and 15 did not. There were a total of 278 different genus calls present across patient samples. The microbiome at time of transfer for those patients with ongoing pregnancy vs. those without ongoing pregnancy was characterized by top genera by sum fraction. Lactobacillus was the top species call for both outcomes.

CONCLUSIONS

The data presented here show the microbiome at the time of embryo transfer can successfully be characterized without altering standard clinical practice. This novel approach, both in specimen collection and analysis, is the first step toward the goal of determining physiologic from pathophysiologic microbiota. Further studies will help delineate if differences in the microbiome at the time of embryo transfer have a reliable impact on pregnancy outcome.

TLR4 Signaling Is a Major Mediator of the Female Tract Response to Seminal Fluid in Mice

Seminal fluid interacts with epithelial cells lining the female reproductive tract to induce expression of proinflammatory cytokines and chemokines, initiating immune tolerance mechanisms to facilitate pregnancy. TGFB cytokines are key signaling agents in seminal plasma but do not fully account for the female response to seminal fluid. We hypothesized that additional molecular pathways are utilized in seminal fluid signaling. Affymetrix microarray was employed to compare gene expression in the endometrium of mice 8 h after mating with either intact males or seminal fluid deficient (SVX/VAS) males. Bioinformatics analysis revealed TLR4 signaling as a strongly predicted upstream regulator activated by the differentially expressed genes and implicated TGFB signaling as a second key pathway. Quantitative PCR and microbead data confirmed that seminal fluid induces endometrial synthesis of several TLR4-regulated cytokines and chemokines, including CSF3, CXCL1, CXCL2, IL1A, IL6, LIF, and TNF. In primary uterine epithelial cells, CSF3, CXCL1, and CXCL2 were strongly induced by the TLR4 ligand LPS but suppressed by TGFB, while IL1A, TNF, and CSF2 were induced by both ligands. TLR4 was confirmed as essential for the full endometrial cytokine response using mice with a null mutation in Tlr4, where seminal fluid failed to induce endometrial Csf3, Cxcl2, Il6, and Tnf expression. This study provides evidence that TLR4 contributes to seminal fluid modulation of the periconception immune environment. Activation of TLR4 signaling by microbial or endogenous components of seminal fluid is thus implicated as a key element of the female tract response to seminal fluid at the outset of pregnancy in mice.

Alkaline phosphatase protects lipopolysaccharide-induced early pregnancy defects in mice

Excessive cytokine inflammatory response due to chronic or superphysiological level of microbial infection during pregnancy leads to pregnancy complications such as early pregnancy defects/loss and preterm birth. Bacterial toxin lipopolysaccharide (LPS), long recognized as a potent proinflammatory mediator, has been identified as a risk factor for pregnancy complications. Alkaline phosphatase (AP) isozymes have been shown to detoxify LPS by dephosphorylation. In this study, we examined the role of alkaline phosphatase (AP) in mitigating LPS-induced early pregnancy complications in mice. We found that 1) the uterus prior to implantation and implantation sites following embryo implantation produce LPS recognition and dephosphorylation molecules TLR4 and tissue non-specific AP (TNAP) isozyme, respectively; 2) uterine TNAP isozyme dephosphorylates LPS at its sites of production; 3) while LPS administration following embryo implantation elicits proinflammatory cytokine mRNA levels at the embryo implantation sites (EISs) and causes early pregnancy loss, dephosphorylated LPS neither triggers proinflammatory cytokine mRNA levels at the EISs nor induces pregnancy complications; 4) AP isozyme supplementation to accelerate LPS detoxification attenuates LPS-induced pregnancy complications following embryo implantation. These findings suggest that a LPS dephosphorylation strategy using AP isozyme may have a unique therapeutic potential to mitigate LPS- or Gram-negative bacteria-induced pregnancy complications in at-risk women.

Polarized Epithelial Cells Secrete Interleukin 6 Apically in the Bovine Endometrium

Endometrial epithelial cells are the first line of defense against pathogenic bacteria infecting the uterus. Innate immune responses by these polarized epithelial cells to bacteria and tissue damage are characterized by release of the chemokine (C-X-C motif) ligand 8 (CXCL8) to attract immune cells from the circulation to the site of infection, where they are regulated by the cytokine interleukin (IL) 6. The present study tested the hypothesis that IL6 is predominantly secreted apically from polarized bovine endometrial epithelial cells in response to stimuli associated with bacterial infection and tissue damage. In postpartum animals, concentrations of IL6, but not of CXCL8, were higher in uterine mucus than in peripheral blood. In vitro, polarized endometrial epithelial cells only secreted IL6 apically when treated with bacteria, the pathogen-associated molecule lipopolysaccharide, or the damage-associated molecule IL1alpha, whereas CXCL8 accumulated apically and basolaterally. Furthermore, IL6 accumulated apically irrespective of whether lipopolysaccharide was applied to the apical or basolateral surface of epithelial cells. Secretion of IL6 from epithelial cells was dependent on the trans-Golgi network but was not affected by exogenous ovarian steroids or by coculture with stromal cells. However, a confluent epithelium was essential to protect underlying stromal cells against noxious challenges, including bacteria, lipopolysaccharide, IL1alpha, and a cytolysin. In summary, when a confluent endometrial epithelial cell barrier is faced with infection and damage, chemokines attract immune cells to the uterine lumen, but IL6 is solely secreted apically to ensure immune cells are only exposed to IL6 once they reach the lumen.

Host detection and the stealthy phenotype in influenza virus infection

The innate host response to influenza virus infection plays a critical role in determining the subsequent course of infection and the clinical outcome of disease. The host has a diverse array of detection and effector mechanisms that are able to recognize and initiate effective antiviral responses. In opposition, the virus utilizes a number of distinct mechanisms to evade host detection and effector activity in order to remain "stealthy" throughout its replication cycle. In this review, we describe these host and viral mechanisms, including the major pattern recognition receptor families (the TLRs, NLRs, and RLRs) in the host and the specific viral proteins such as NS1 that are key players in this interaction. Additionally, we explore nonreductive mechanisms of viral immune evasion and propose areas important for future inquiry.

Estradiol regulation of constitutive and keratinocyte growth factor-induced CCL20 and CXCL1 secretion by mouse uterine epithelial cells

PROBLEM

Estradiol can directly affect epithelial cells or indirectly affect epithelial cells via stromal fibroblast secretion of growth factors, such as keratinocyte growth factor (KGF). The purpose of the present study was to determine whether estradiol regulates constitutive as well as KGF-induced uterine epithelial cell secretion of CCL20 and CXCL1.

METHOD OF STUDY

Freshly isolated and polarized uterine epithelial cells from Balb/c mice were cultured with estradiol in the presence or absence of KGF. CCL20 and CXCL1 were measured by ELISA.

RESULTS

Estradiol inhibited CCL20 secretion by freshly isolated and polarized uterine epithelial cells in the presence or absence of KGF. Unexpectedly, it enhanced KGF-induced CXCL1 secretion beyond that seen with KGF alone. Estradiol increased CXCL1 secretion at 24 hr and inhibited CCL20 at 48 hr. The effects of estradiol are specific in that progesterone, cortisol, dihydrotestosterone, and aldosterone had no effect on either CCL20 or CXCL1 secretion. The inhibitory effect of estradiol on CCL20 secretion was reversed with ICI 182,780, an estrogen receptor antagonist, indicating that this effect is estrogen receptor mediated.

CONCLUSIONS

Our data indicate that estradiol is important in regulating the effects of KGF on mouse uterine epithelial cell secretion of CCL20 and CXCL1.

Potential influence of the microbiome on infertility and assisted reproductive technology

Although an altered vaginal microbiota has been demonstrated to affect parturition, its role in assisted reproductive technologies is uncertain. Nevertheless, the effect of known pathogens such as Mycoplasma tuberculosis, Chlamydia trachomatis, and Neisseria gonorrhoeae is clear, causing subclinical changes thought to be risk factors in subfertility. The Human Microbiome Project (HMP) has allowed for metagenomic studies to aid in characterizing normal vaginal flora. Recent findings from the HMP demonstrate that many different species of Lactobacillus are present in the vaginal tract, with a few that predominate. Studies that characterize the vaginal microbiome in assisted reproductive technology support the hypothesis that colonizing the transfer-catheter tip with Lactobacillus crispatus at the time of embryo transfer may increase the rates of implantation and live birth rate while decreasing the rate of infection. In addition, there is some evidence that a progesterone-resistant endometrium might increase the risk of an abnormal vaginal microbiome.

Microbial TLR Agonists and Humoral Immunopathogenesis in HIV Disease

Although T cells are the primary and most-studied targets of the Human Immunodeficiency Virus (HIV), B cells, especially memory B lymphocytes, are also chronically depleted in the course of HIV disease. Although the lack of CD4+ T cell help may explain these deficiencies, intrinsic defects in B lymphocytes appear to contribute to B cell depletion and reduced antibody (Ab) production in the setting of HIV, especially of some antigens eliciting T cell-independent responses. The gut mucosal barrier is disrupted in HIV disease, resulting in increased systemic exposure to microbial products such as Toll-Like Receptor (TLR) agonists. The association of enhanced systemic levels of TLR agonists and B cell dysfunction in HIV disease is not understood. This review discusses the potential role of microbial TLR agonists in the B cell depletion, enhanced autoantibody production and impaired responses to vaccination observed in HIV-infected hosts. Increased microbial translocation in HIV infection may drive B cells to produce autoantibodies and increase susceptibilities of B cells to apoptosis through activation-induced cell death. Determining the mechanisms of B cell perturbations in HIV disease will inform the design of novel strategies of improve immune responses to vaccines, reduce opportunistic infections and slow disease progression.

Polarised bovine endometrial epithelial cells vectorially secrete prostaglandins and chemotactic factors under physiological and pathological conditions

Epithelial cells of the endometrium secrete prostaglandins to regulate the bovine oestrous cycle and form a functional barrier to microbes. However, bacterial infection of the endometrium commonly causes infertility in dairy cattle by disrupting endometrial physiology. Epithelial cell cultures are used to study the mechanisms of physiology and pathology, but 2D cultures may not reflect the 3D complexity of the epithelium. In this study, a polarised epithelial cell transwell culture was developed, using transepithelial resistance (TER), to monitor epithelial integrity. Polarised epithelial cells were treated with oxytocin and arachidonic acid to test physiological function and with lipopolysaccharide (LPS) to mimic bacterial infection. Supernatants were analysed for prostaglandin E(2) (PGE), prostaglandin F(2)(α), the chemokine interleukin-8 (IL8) and the ability of supernatants to induce neutrophil migration. Confluent epithelial cells established polarity when TER was >1800  Ω cm(2) and predominantly released prostaglandins basolaterally. In contrast, IL8 from epithelial cells accumulated apically and the supernatants were highly chemotactic for neutrophils. The striking exception was when the epithelial cells were treated with LPS in the apical or basolateral compartment independently, which led to the release of IL8 towards the treated compartment. Although stromal cells also accumulated PGE and IL8 in response to treatment, co-culture of stromal cells in the well below polarised epithelial cells did not influence cellular responses. In conclusion, polarised endometrial epithelial cells vectorially released prostaglandins and chemokines to reflect their respective mechanistic roles in physiology and pathology.

Mouse estrous cycle regulation of vaginal versus uterine cytokines, chemokines, α-/β-defensins and TLRs

This study investigates the cyclic changes in innate immunity in the female reproductive tract (FRT) of mice during the estrous cycle. By examining uterine and vaginal tissues and secretions we show that innate immunity varies with the stage of the estrous cycle and site in the FRT. Secretions from the uterine lumen contained cytokines and chemokines that were significantly higher at proestrus and estrus relative to that measured at diestrus. In contrast, analysis of vaginal secretions indicated that only IL-1β and CXCL1/mouse KC changed during the cycle, with highest levels measured at diestrus and estrus. In contrast, vaginal α-defensin 2 and β-defensins 1-4 mRNA levels peaked at proestrus and estrus and are expressed 1-4 logs greater than that seen in the uterus. These studies further indicate that TLR5 and TLR12 in the uterus, and TLR1, TLR2, TLR5 and TLR13 in the vagina varies with stage of the estrous cycle, with some peaking at proestrus/estrus and others at diestrus. Overall, these studies indicate that innate immune parameters in the uterus and vagina are separate and discrete, and regulated precisely during the estrous cycle.

Immunohistochemical localization of beta defensins in the endometrium of rat uterus during the postpartum involution period

β-Defensins are small cationic molecules that have antimicrobial actions against bacteria, fungi and viruses and contribute to mucosal immune responses at epithelial sites. The female reproductive tract is an important site of defensin production. This study was conducted to determine the possible changes in proportions and localization of β-defensin 1-4 in the rat uterus at the 1st, 3th, 5th, 10th and 15th days of postpartum and at the period of diestrus using immunohistochemical techniques. In the present study, it was determined that β-defensin 1-4 were generally found in all structural components of the endometrium (luminal and glandular epithelium, stromal cells and blood vessels) in both the nucleus and the cytoplasm of cells during the involution period and diestrus. Suprisingly, immunoreaction of β-defensin 2 was also observed in the lateral membrane of the luminal and glandular epithelial cells on the 10th day of involution and immunostaining of β-defensin 4 was also localized in the apical membrane of the luminal and glandular epithelial cells. The current study demonstrated β-defensin 1-4 immunoreactivities in the endothelium of blood vessels were stronger throughout the involution period. Although β-defensins 2 and 3 were localized in both the nuclei and the cytoplasm of endothelial cells, β-defensins 1 and 4 were present in only cytoplasm. These results show that the most component of rat endometrium expresses human β-defensin 1-4 in a involution-dependent manner. Therefore it may be asserted that these molecules constitute a organised protection to prevent uterus from probable infections during the involution process.

Effect of oestradiol and pathogen-associated molecular patterns on class II-mediated antigen presentation and immunomodulatory molecule expression in the mouse female reproductive tract

Cells of the female reproductive tract (FRT) can present antigen to naive and memory T cells. However, the effects of oestrogen, known to modulate immune responses, on antigen presentation in the FRT remain undefined. In the present study, DO11.10 T-cell antigen receptor transgenic mice specific for the class II MHC-restricted ovalbumin (OVA) 323-339 peptide were used to study the effects of oestradiol and pathogen-associated molecular patterns on antigen presentation in the FRT. We report here that oestradiol inhibited antigen presentation of OVA by uterine epithelial cells, uterine stromal cells and vaginal cells to OVA-specific memory T cells. When ovariectomized animals were treated with oestradiol for 1 or 3 days, antigen presentation was decreased by 20-80%. In contrast, incubation with PAMP increased antigen presentation by epithelial cells (Pam(3)Cys), stromal cells (peptidoglycan, Pam(3)Cys) and vaginal cells (Pam(3)Cys). In contrast, CpG inhibited both stromal and vaginal cell antigen presentation. Analysis of mRNA expression by reverse transcription PCR indicated that oestradiol inhibited CD40, CD80 and class II in the uterus and CD40, CD86 and class II in the vagina. Expression in isolated uterine and vaginal cells paralleled that seen in whole tissues. In contrast, oestradiol increased polymeric immunoglobulin receptor mRNA expression in the uterus and decreased it in the vagina. These results indicate that antigen-presenting cells in the uterus and vagina are responsive to oestradiol, which inhibits antigen presentation and co-stimulatory molecule expression. Further, these findings suggest that antigen-presenting cells in the uterus and vagina respond to selected Toll-like receptor agonists with altered antigen presentation.

Microbial Translocation and B Cell Dysfunction in Human Immunodeficiency Virus Disease

The gut mucosal barrier disrupted in HIV disease, resulting in increased systemic exposure to microbial products such as Lipo Polys Accharide (LPS). The association of enhanced microbial translocation and B cell dysfunction in HIV disease is not fully understood. High dose and short term exposure of microbial Toll-Like Receptor (TLR) agonists were used as vaccine adjuvants, however, low dose and long term exposure of TLR agonists could be harmful. The characteristics of B cell dysfunction in HIV disease included B cell, especially memory B cell depletion, enhanced levels of autoimmune antibodies and impaired vaccine or antigen responsiveness. This review discusses and explores the possibility of the effect of microbial translocation on memory B cell depletion and impaired vaccine responses in HIV infection. By determining the mechanisms of B cell depletion and perturbations in HIV disease, it may be possible to design interventions that can improve immune responses to vaccines, reduce selected opportunistic infections and perhaps slow disease progression.

Keratinocyte Growth Factor Stimulates Macrophage Inflammatory Protein 3α and Keratinocyte-derived Chemokine Secretion by Mouse Uterine Epithelial Cells

PROBLEM

communication between uterine epithelial cells and the underlying stromal fibroblasts is critical for proper endometrial function. Stromal fibroblast-derived growth factors have been shown to regulate epithelial immune functions. The purpose of this study was to determine whether keratinocyte growth factor (KGF) regulates uterine epithelial cell chemokine and antimicrobial secretion.

METHOD OF STUDY

uterine epithelial cells were isolated from Balb/c mice and cultured in either 96-well plates or transwell inserts. Epithelial cells were treated with KGF, epidermal growth factor (EGF), or hepatocyte growth factor (HGF). Macrophage inflammatory protein 3α (MIP3α) and keratinocyte-derived chemokine (KC) levels were measured by ELISA.

RESULTS

keratinocyte growth factor stimulated the secretion of MIP3α and KC. The effects on MIP3α by KGF were specific because EGF and HGF had no effect. In contrast, KGF, EGF, and HGF had similar effects on KC. Furthermore, KGF administered to the apical side of epithelial cells had no effect on MIP3α or KC secretion, indicating that the KGF receptor is located on the basolateral surface of uterine epithelial cells.

CONCLUSION

we demonstrate that KGF plays a role in uterine epithelial cell secretion of MIP3α and KC, key immune mediators involved in the protection of mucosal surfaces in the female reproductive tract.

Immunological characterization of the equine airway epithelium and of a primary equine airway epithelial cell culture model

Our understanding of innate immunity within the equine respiratory tract is limited despite growing evidence for its key role in both the immediate defense and the shaping of downstream adaptive immune responses to respiratory disease. As the first interface to undergo pathogen invasion, the respiratory epithelium is a key player in these early events and our goal was to examine the innate immune characteristics of equine respiratory epithelia and compare them to an in vitro equine respiratory epithelial cell model cultured at the air-fluid interface (AFI). Respiratory epithelial tissues, isolated epithelial cells, and four-week old cultured differentiated airway epithelial cells collected from five locations of the equine respiratory tract were examined for the expression of toll-like receptors (TLRs) and host defense peptides (HDPs) using conventional polymerase chain reaction (PCR). Cultured, differentiated, respiratory epithelial cells and freshly isolated respiratory epithelial cells were also examined for the expression of TLR3, TLR9 and major histocompatibility complex (MHC) class I and class II using fluorescence-activated cell sorting (FACS) analysis. In addition, cytokine and chemokine profiles from respiratory epithelial tissues, freshly isolated respiratory epithelial cells, and cultured, differentiated, epithelial cells from the upper respiratory tract were examined using real-time PCR. We found that respiratory epithelial tissues and isolated epithelial cells expressed TLRs 1-4 and 6-10 as well as HDPs, MxA, 2'5' OAS, β-defensin-1, and lactoferrin. In contrast, epithelial cells cultured at the AFI expressed TLRs 1-4 and 6 and 7 as well as MxA, 2'5' OAS, β-defensin-1, but had lost expression of TLRs 8-10 and lactoferrin. In addition, MHC-I and MHC-II surface expression decreased in epithelial cells cultured at the AFI compared to isolated epithelial cells whereas TLR3 and TLR9 were expressed at similar levels. Lastly, we found that equine respiratory epithelial cells express an array of pro-inflammatory, antiviral and regulatory cytokines and that after four weeks of in vitro growth conditions, equine respiratory epithelial cells cultured at the AFI retained expression of GM-CSF, IL-10, IL-8, TGF-β, TNF-α, and IL-6. In summary, we describe the development of an in vitro equine respiratory epithelial cell culture model that is morphologically similar to the equine airway epithelium and retains several key immunological properties. In the future this model will be a used to study equine respiratory viral pathogenesis and cell-to-cell interactions.

Postpartum toll-like receptors and β-defensin 5 mRNA levels in the endometrium of Holstein cows

Toll-like receptors (TLRs) and β-defensins are important components of the innate immune system. This study aimed to evaluate endometrial mRNA levels of TLRs (1/6, 2, 4, and 5) and β-defensin 5 in Holstein cows by quantitative real time RT-PCR. Uterine biopsies were performed from 6 to 12 h after parturition, and cows were divided into two groups: (i) cows with placental retention and clinical signs of uterine infection until 45 days postpartum (n=10) or (ii) cows with normal puerperium (n=10). All cows had detectable levels of TLRs and β-defensin 5 mRNAs, but these levels did not differ between groups (P>0.05). Levels of TLR4 mRNA had a positive and significant correlation with the time required for uterine involution in both groups.

Toll-like receptor 4 mediates the response of epithelial and stromal cells to lipopolysaccharide in the endometrium

BACKGROUND

Ascending infections of the female genital tract with bacteria causes pelvic inflammatory disease (PID), preterm labour and infertility. Lipopolysaccharide (LPS) is the main component of the cell wall of Gram-negative bacteria. Innate immunity relies on the detection of LPS by Toll-like receptor 4 (TLR4) on host cells. Binding of LPS to TLR4 on immune cells stimulates secretion of pro-inflammatory cytokines such as IL-6, chemokines such as CXCL1 and CCL20, and prostaglandin E(2). The present study tested the hypothesis that TLR4 on endometrial epithelial and stromal cells is essential for the innate immune response to LPS in the female genital tract.

METHODOLOGY/PRINCIPAL FINDINGS

Wild type (WT) mice expressed TLR4 in the endometrium. Intrauterine infusion of purified LPS caused pelvic inflammatory disease, with accumulation of granulocytes throughout the endometrium of WT but not Tlr4(-/-) mice. Intra-peritoneal infusion of LPS did not cause PID in WT or Tlr4(-/-) mice, indicating the importance of TLR4 in the endometrium for the detection of LPS in the female genital tract. Stromal and epithelial cells isolated from the endometrium of WT but not Tlr4(-/-) mice, secreted IL-6, CXCL1, CCL20 and prostaglandin E(2) in response to LPS, in a concentration and time dependent manner. Co-culture of combinations of stromal and epithelial cells from WT and Tlr4(-/-) mice provided little evidence of stromal-epithelial interactions in the response to LPS.

CONCLUSIONS/SIGNIFICANCE

The innate immune response to LPS in the female genital tract is dependent on TLR4 on the epithelial and stromal cells of the endometrium.

Activation of the transcription factor, nuclear factor kappa-B, during the estrous cycle and early pregnancy in the pig

Establishment and maintenance of pregnancy in the pig involves intricate communication between the developing conceptuses and the maternal endometrium. This process occurs during trophoblast elongation which is spaciotemporally associated with conceptus synthesis and release of IL1B concomitant with pregnancy-specific endometrial up-regulation of IL-1 receptors, providing the potential for activation of the transcription factor, NFKB. The objective of the current investigation was to determine changes in expression and cellular localization of NFKB and associated factors during the estrous cycle and early pregnancy in the pig. In situ hybridization was used to localize changes in PGR, ESR1, and TNFRSF11A during the peri-implantation period. Quantitative RT-PCR was utilized to demonstrate gene expression changes for NFKB1, RELA, TNFRSF11A, TLR4, NFKBIA and NFKBIB. Transcription factor ELISA demonstrated an overall increase in RELA during the peri-implantation period in both cyclic and pregnant gilts. While the presence of TNFSF11A and TLR4 were both detected, TLR4 expression changes were temporally associated with NFKB expression and activation. Collectively, these data demonstrate that NFKB activation may occur during the period of uterine receptivity in both the cyclic and pregnant endometrium.

Trappin-2/Elafin: a novel innate anti-human immunodeficiency virus-1 molecule of the human female reproductive tract

Trappin-2/Elafin is a serine protease inhibitor that plays a major role as an anti-inflammatory mediator at mucosal surfaces. In addition, Trappin-2/Elafin has antibacterial activity against Gram-positive and Gram-negative bacterial and fungal pathogens. In this study we examined the production of Trappin-2/Elafin by epithelial cells from the human upper and lower female reproductive tract as well as its activity as an anti-human immunodeficiency virus (HIV)-1 molecule. We found that primary uterine, Fallopian tube, cervical and ectocervical epithelial cells produce Trappin-2/Elafin constitutively and that production of Trappin-2/Elafin is enhanced following stimulation with Poly(I:C), especially by the uterine cells. Given the presence of Trappin-2/Elafin in the reproductive tract, we tested the ability of recombinant Trappin-2/Elafin to inhibit HIV-1, an important sexually transmitted pathogen. We found that recombinant Trappin-2/Elafin was able to inhibit both T-cell-tropic X4/IIIB and macrophage-tropic R5/BaL HIV-1 in a dose-dependent manner. The inhibitory activity was observed when virus was incubated with Trappin-2/Elafin but not when Trappin-2/Elafin was added to cells either before infection or after infection. This suggests that the mechanism of inhibition is likely to be a direct interaction between HIV-1 and Trappin-2/Elafin. Additionally, we measured the levels of secreted Trappin-2/Elafin in cervico-vaginal lavages (CVL) from both HIV-positive and HIV-negative women and found that average levels of secreted Trappin-2/Elafin were higher in the CVL from HIV-negative women, although the values did not reach statistical significance. We also found that women at the secretory phase of the menstrual cycle produced more Trappin-2/Elafin in CVL relative to women at the proliferative phase of the menstrual cycle. Our data suggest that Trappin-2/Elafin might be an important endogenous microbicide of the female reproductive tract that is protective against HIV-1.

Expression of genes associated with immunity in the endometrium of cattle with disparate postpartum uterine disease and fertility

BACKGROUND

Contamination of the uterine lumen with bacteria is ubiquitous in cattle after parturition. Some animals develop endometritis and have reduced fertility but others have no uterine disease and readily conceive. The present study tested the hypothesis that postpartum cattle that develop persistent endometritis and infertility are unable to limit the inflammatory response to uterine bacterial infection.

METHODS

Endometrial biopsies were collected several times during the postpartum period from animals that were subsequently infertile with persistent endometritis (n = 4) or had no clinical disease and conceived to first insemination (n = 4). Quantitative PCR was used to determine the expression of candidate genes in the endometrial biopsies, including the Toll-like receptor (TLR 1 to 10) family of innate immune receptors, inflammatory mediators and their cognate receptors. Selected proteins were examined by immunohistochemistry.

RESULTS

The expression of genes encoding pro-inflammatory mediators such as interleukins (IL1A, IL1B and IL6), and nitric oxide synthase 2 (NOS2) were higher during the first week post partum than subsequently. During the first week post partum, there was higher gene expression in infertile than fertile animals of TLR4, the receptor for bacterial lipopolysaccharide, and the pro-inflammatory cytokines IL1A and IL1B, and their receptor IL1R2. The expression of genes encoding other Toll-like receptors, transforming growth factor beta receptor 1 (TGFBR1) or prostaglandin E2 receptors (PTGER2 and PTGER4) did not differ significantly between the animal groups. Gene expression did not differ significantly between infertile and fertile animals after the first week postpartum. However, there were higher ratios of IL1A or IL1B mRNA to the anti-inflammatory cytokine IL10, during the first week post partum in the infertile than fertile animals, and the protein products of these genes were mainly localised to the epithelium of the endometrium.

CONCLUSION

Cattle may maintain fertility by limiting the inflammatory response to postpartum bacterial infection in the endometrium during the first week after parturition.

Comparison of immune cell recruitment and function in endometrium during development of epitheliochorial (pig) and hemochorial (mouse and human) placentas

The role of maternal immune cells in early implantation sites has received special attention from reproductive biologists because immune cells participate in tissue transplant rejection. During normal pregnancy, endometrial immune cells differ from those in blood by subset distribution and appear to be activated but non-destructive of conceptuses. The immune system evolved well before placental mammals. By comparing the regulation and functions of endometrial immune cells between species in two phylogenetic clades that model differently evolved placental types (pig (Sus scrofa) versus mouse (Mus musculus) and human (Homo sapiens)), we seek to understand how "non-self" trophoblast cells thrive in most pregnancies. Our studies suggest recruitment of specific immune cells to conceptus-associated endometrium and immune cell-promoted endometrial angiogenesis are of key importance for mammalian conceptus well-being.

The involvement of the Toll-like receptor family in ovulation

INTRODUCTION

Ovulation is similar to an inflammatory response and is associated with increased production of prostaglandins as well as local growth regulatory factors. However, the expression and function of innate immune cell-related genes in non-immune cells within the ovary has been reported recently and provides a novel and important regulatory system during ovulation.

DISCUSSION

Several members of the Toll-like receptor (TLR) surveillance system are expressed in granulosa cells and cumulus cells. These receptors can be activated by pathogens as well as endogenous ligands leading to the induction and release of potent cytokines and chemokines from cumulus cells.

CONCLUSION

These inflammatory factors exert potent effects on cumulus cell-oocyte expansion, ovulation, transport and fertilization indicating that ovulation is a more complex immune-inflammatory process than previously recognized.

Toll-like receptors in female reproductive tract and their menstrual cycle dependent expression

Rapid innate immune defences against infection usually involve the recognition of invading pathogens by specific pattern recognition receptors recently attributed to the family of Toll-like receptors (TLR). TLRs constitute a major part of innate immune system, and have been characterised in different tissues and organs. Reports from our laboratory and others have demonstrated the existence of TLRs in the female reproductive tract, yet TLRs have not been explored completely in this system. There is little known about variation in TLR expression during the menstrual cycle and the effects that sex hormones may have on their expression and function. Here, we review recent information regarding the existence of TLRs in the female reproductive tract, their function in the maintenance of innate immune system in this tract and their potential role in pregnancy.

Antiviral responses of human Fallopian tube epithelial cells to toll-like receptor 3 agonist poly(I:C)

OBJECTIVE

To examine the expression of toll-like receptors (TLR) by primary human Fallopian tube epithelial cells (FTEC) and to determine whether exposure to the TLR3 agonist poly(I:C) induces an antiviral response.

DESIGN

Tissue culture study.

SETTING

University medical center.

PATIENT(S)

Premenopausal women undergoing hysterectomy.

INTERVENTION(S)

Primary human FTEC were grown to confluence and high transepithelial resistance and treated with TLR agonists. Conditioned media was collected and RNA was extracted and analyzed for the expression of cytokines, chemokines, and antimicrobial genes.

MAIN OUTCOME MEASURE(S)

The RNA was analyzed by real-time polymerase chain reaction and protein levels were assessed by enzyme-linked immunosorbent assay.

RESULT(S)

The FTEC were demonstrated to express TLR1-9 but not 10. Treatment of FTEC with TLR3 agonist poly(I:C) resulted in increased expression of interleukin-8, tumor-necrosis factor alpha, human beta-defensin 2, interferon beta, and interferon stimulated genes myxovirus resistance gene 1, 2',5'-oligoadenylate synthetase, and protein kinase R. Additionally, FTEC exposed to poly(I:C) also resulted in the induction of TLR2, TLR3, and TLR7.

CONCLUSION(S)

Our results suggest that FTEC are sensitive to viral infection and/or exposure to viral double-stranded RNA and can respond by secreting proinflammatory cytokines that mediate the initiation of an inflammatory response as well as expressing genes that can directly inhibit viral replication.

Role of NF-kappaB in constitutive expression of MAIL in epidermal keratinocytes

Molecule possessing ankyrin-repeats induced by lipopolysaccharide (MAIL) is a nuclear IkappaB protein that is also known as interleukin-1-inducible nuclear ankyrin repeat protein and inhibitor of nuclear factor kappaBzeta (IkappaBzeta). We previously observed that MAIL-deficient mice were affected by atopic dermatitis-like skin lesions and demonstrated the importance of MAIL in the skin. In this study, we investigated MAIL expression in mouse keratinocytes. MAIL mRNA was constitutively expressed in the skin epidermis. MAIL expression was also confirmed in primary keratinocytes and the PAM212 keratinocyte cell line. The inhibitors of nuclear factor kappaB (NF-kappaB)-Bay11-7082 and the IkappaBalphaM supersuppressor-considerably downregulated MAIL expression in the keratinocytes. Immunoreactivity for NF-kappaB components was localized in the cytoplasm and nucleus of normal unstimulated keratinocytes. The expression level of MAIL in the skin did not change following lipopolysaccharide (LPS) administration to mice. Interestingly, in accordance with the in vivo findings, the MAIL expression level did not change following LPS stimulation even in primary keratinocytes; however, MAIL expression was strongly increased by interleukin-1 stimulation. These results collectively suggest that the constitutive expression of MAIL in keratinocytes is controlled, at least in part, by NF-kappaB and that there may be LPS-specific repressive mechanisms that inhibit MAIL induction.

Toll‐like receptors in the gonads and reproductive tract: emerging roles in reproductive physiology and pathology

Interactions between the immune system and reproductive system have important consequences for fertility and reproductive health in general. There is increasing evidence that many of the interactions between the immune and reproductive systems involve the Toll-like receptors (TLRs). While there is no doubt that TLRs are important in providing protection against infection in the reproductive tract, there is increasing evidence for the involvement of TLRs in more basic pathology and physiology of reproduction. In the female, TLRs have been implicated in critical aspects of ovarian, endometrial and placental function, as well as in ovarian cancer, pelvic inflammatory disease, intrauterine growth restriction, pre-eclampsia and preterm birth. In the male, TLRs appear to play a role in the control of testicular steroidogenesis and spermatogenesis in disease and, potentially, during normal function, as well. Recent studies also have begun to highlight the role of various TLRs in the aetiology of prostatitis and prostatic cancer. Given the nascent state of knowledge concerning this important area, it is clear that more studies are needed, which should provide valuable new insights into the biology of the TLRs and reproductive function in general.

Trichomonas vaginalis lipophosphoglycan triggers a selective upregulation of cytokines by human female reproductive tract epithelial cells

Trichomonas vaginalis is one of the most common nonviral sexually transmitted human infections and, worldwide, has been linked to increased incidence of human immunodeficiency virus type 1 transmission, preterm delivery, low birth weight, cervical cancer, and vaginitis. The molecular pathways that are important in initiating host inflammatory and immune responses to T. vaginalis are poorly understood. Here we report interactions of human cervicovaginal epithelial cells with the most abundant cell surface glycoconjugate of the parasite, the T. vaginalis lipophosphoglycan (LPG). Purified LPG mediated the adhesion of parasites to human vaginal epithelial cells in a dose-dependent manner. Furthermore, T. vaginalis LPG (but not LPG from Tritrichomonas foetus, the causative agent of bovine trichomoniasis) induced a selective upregulation of chemotactic cytokines by human endocervical, ectocervical, and vaginal epithelial cells, which do not express Toll-like receptor 4/MD2. The T. vaginalis LPG triggered interleukin 8 (IL-8), which promotes the adhesion and transmigration of neutrophils across the endothelium, and macrophage inflammatory protein 3alpha, which is a chemoattractant for immune cells and is essential for dendritic cell maturation. These effects were dose dependent and sustained in the absence of cytotoxicity and IL-1beta release and utilized, at least in part, a signaling pathway independent from the Toll-like/IL-1 receptor adaptor protein MyD88.