CXCL10 and IL-6 induce chemotaxis in human trophoblast cell lines

Modulation of cytokine and chemokine secretions in rhesus monkey trophoblast co-culture with decidual but not peripheral blood monocyte-derived macrophages

PROBLEM

Decidual macrophages are thought to promote pregnancy success, in part through interactions with invading trophoblast cells in hemochorial placentation. However, the factors that constitute this regulatory cross talk are not well understood.

METHOD OF STUDY

Rhesus monkey decidual and peripheral blood-derived macrophages were co-cultured with primary Rhesus trophoblasts. Macrophage functions including cell-surface marker expression, antigen uptake and processing, in vitro migration, and cytokine and chemokine secretions were evaluated.

RESULTS

While most macrophage functions were unchanged by trophoblast co-culture, changes in the secretion of selected cytokines and the migration of trophoblasts were noted when decidual (but generally, not peripheral blood monocyte-derived) macrophages were cultured with trophoblasts. In addition, basal secretion differed significantly between peripheral blood-derived and decidual macrophages for a broad spectrum of cytokines. When trophoblasts were pre-treated with an anti-Mamu-AG antibody, 25D3, there was no change in cytokine or chemokine secretion.

CONCLUSION

Macrophage cytokine expression can be modulated by trophoblast co-culture, but it remains unclear how Mamu-AG is involved.

Endometrial implantation factors in women with submucous uterine fibroids

Uterine fibroids are benign tumours, which are associated with subfertility and early pregnancy loss. This study was carried out to examine the effect of submucous fibroids on concentrations of glycodelin, insulin-like growth factor binding protein-1 (IGFBP-1), interleukin-6 (IL-6), interleukin-10 (IL-10), tumour necrosis factor α (TNFα) and osteopontin in uterine flushings. Premenopausal women with a certain diagnosis of submucous fibroid confirmed on three-dimensional saline infusion sonohysterography were recruited into the study. The control group included women without ultrasonic evidence of any uterine or endometrial pathology. All women had uterine flushings performed 7days post LH surge. Enzyme linked immunoassays were performed to analyse glycodelin, IL-6, IL-10, TNFα and osteopontin, whilst immunoradiometric assay was used to analyse IGFBP-1. In 23 women with submucous fibroids, the concentrations of glycodelin and IL-10 in uterine flushings were significantly lower compared with 17 women in the control group (P=0.002; P=0.007, respectively). There were no significant differences between the two groups in concentrations of IGFBP-1, IL-6, TNFα and osteopontin. Women with submucous fibroids had significantly lower concentrations of glycodelin and IL-10 in mid-luteal phase uterine flushings. This finding may explain the association with submucous fibroids and adverse reproductive outcomes. Uterine fibroids are small growths from the muscle of the uterus (womb). Submucous fibroids protrude into the cavity of the womb. We do not know what causes fibroids to form and grow. In most women, fibroids cause no symptoms and they are sometimes detected on routine gynaecological examination. In some women, however, fibroids can cause heavier and longer menstrual periods. Another problem associated with fibroids is bleeding between periods. The effect of fibroids on fertility is not clear, but some doctors believe that they may also cause infertility and early miscarriage. This study tried to see whether presence of submucous fibroids has any effect on various substances produced by the lining of the womb to facilitate development of early pregnancy. Women with a confirmed diagnosis of submucous fibroids were asked to attend the clinic and have the uterine cavity flushed with a special solution 7days after ovulation. The fluid, which was taken back from the womb, was then analysed to measure the amounts of substances that favour pregnancy development. Women with a normal uterine cavity were also asked to have the uterine cavity flushed to act as a comparison. The study showed that the uterine cavities of women with submucous fibroids were producing decreasing amount of substances favourable to early pregnancy development. We speculate that this may explain why some women with submucous fibroids have difficulties falling pregnant. Our findings should be helpful to doctors advising women with submucous fibroids who wish to start a family.

Expression of chemokine decoy receptors and their ligands at the porcine maternal-fetal interface

Successful pregnancy requires coordinated maternal-fetal cross-talk to establish vascular connections that support conceptus growth. In pigs, two waves of spontaneous fetal loss occur and 30-40% of conceptuses are lost before parturition. Previous studies associated these losses with decreased angiogenic and increased inflammatory cytokines. Chemokines, a sub-category of cytokines, and decoy receptors control leukocyte trafficking, angiogenesis and development. The availability of chemokines is regulated by three non-signalling decoy receptors: chemokine decoy receptor (D6), Duffy antigen receptor for chemokines (DARC) and Chemocentryx decoy receptor (CCX CKR). We hypothesized that the expression of these receptors and their chemokine ligands regulate the porcine pregnancy success or failure. Here, we describe for the first time the transcription and translation of all three decoy receptors and several chemokine ligands in endometrium and trophoblast associated with healthy and arresting conceptuses at gestation day (gd) 20 and gd50. Among decoy receptors, transcripts for DARC were significantly reduced in endometrium, whereas that for CCX CKR were significantly increased in endometrium and trophoblast at gd50 arresting compared with healthy sites. However, western blot analysis revealed no differences in decoy receptor expression between healthy and arresting tissues. Transcripts for decoy receptor ligands CCL2, CCL3, CCL4, CCL5, CCL11, CCL19, CCL21, CXCL2 and CXCL8 were stable between healthy and arresting littermates. Quantification by SearchLight chemiluminescent protein array confirmed ligand expression at the protein level. These data indicate that decoy receptors and ligands are expressed at the porcine maternal-fetal interface and dysregulation of decoy receptor (DARC and CCX CKR) transcripts occurs at sites of fetal arrest.

Aberrant expression of selectin E, CXCL1, and CXCL13 in chronic endometritis

Chronic endometritis is often identified in the patients with unexplained infertility, and is histopathologically characterized by infiltration of plasmacytes within the endometrial stroma. In parallel with stromal plasmacyte infiltration, the endometrial functional layer in chronic endometritis is invaded by B cells, which are a rare leukocyte subset residing within the basal layer in the nonpathological endometrium. In this study, we investigated the molecular expression underlying this unusual increase of B cells in chronic endometritis. Twenty-two out of 76 infertile patients were diagnosed with chronic endometritis from the stromal plasmacyte infiltration, and the endometrium contained numerous stromal B-cell aggregates and glandular single B cells. However, the other major leukocyte subsets, including T cells, natural killer cells, macrophages, and neutrophils were comparable in densities in chronic endometritis and nonpathological endometrium. The microvascular endothelium showed immunoreactivity to adhesion molecule selectin E and chemokine CXCL13 along with immunoreactivity to CXCL1 in the glandular epithelium in chronic endometritis, but not in the nonpathological endometrium. Lipopolysaccharide significantly induced surface selectin E expression and CXCL13 secretion in uterine microvascular endothelial cells, and CXCL1 secretion in endometrial epithelial cells in vitro. These findings indicated that the aberrant local microenvironment triggered possibly by bacterial infection has a role in selective extravasation of circulating B cells in chronic endometritis.

Enterovirus infection, CXC chemokine ligand 10 (CXCL10), and CXCR3 circuit: a mechanism of accelerated beta-cell failure in fulminant type 1 diabetes

OBJECTIVE

Fulminant type 1 diabetes is characterized by the rapid onset of severe hyperglycemia and ketoacidosis, with subsequent poor prognosis of diabetes complications. Causative mechanisms for accelerated beta-cell failure are unclear.

RESEARCH DESIGN AND METHODS

Subjects comprised three autopsied patients who died from diabetic ketoacidosis within 2-5 days after onset of fulminant type 1 diabetes. We examined islet cell status, including the presence of enterovirus and chemokine/cytokine/major histocompatibility complex (MHC) expressions in the pancreata using immunohistochemical analyses and RT-PCR.

RESULTS

Immunohistochemical analysis revealed the presence of enterovirus-capsid protein in all three affected pancreata. Extensive infiltration of CXCR3 receptor-bearing T-cells and macrophages into islets was observed. Dendritic cells were stained in and around the islets. Specifically, interferon-gamma and CXC chemokine ligand 10 (CXCL10) were strongly coexpressed in all subtypes of islet cells, including beta-cells and alpha-cells. No CXCL10 was expressed in exocrine pancreas. Serum levels of CXCL10 were increased. Expression of MHC class II and hyperexpression of MHC class I was observed in some islet cells.

CONCLUSIONS

These results strongly suggest the presence of a circuit for the destruction of beta-cells in fulminant type 1 diabetes. Enterovirus infection of the pancreas initiates coexpression of interferon-gamma and CXCL10 in beta-cells. CXCL10 secreted from beta-cells activates and attracts autoreactive T-cells and macrophages to the islets via CXCR3. These infiltrating autoreactive T-cells and macrophages release inflammatory cytokines including interferon-gamma in the islets, not only damaging beta-cells but also accelerating CXCL10 generation in residual beta-cells and thus further activating cell-mediated autoimmunity until all beta-cells have been destroyed.

VIP modulates the pro-inflammatory maternal response, inducing tolerance to trophoblast cells

BACKGROUND AND PURPOSE

Successful embryo implantation is followed by a local pro-inflammatory and Th1 response, subsequently controlled by a Th2 response. Vasoactive intestinal peptide (VIP) has anti-inflammatory effects and promotes tolerogenic/Th2 responses while favouring embryonic development. We investigated the potential regulatory role of VIP on human trophoblast cells, maternal pro-inflammatory responses and trophoblast-maternal leukocyte interactions.

EXPERIMENTAL APPROACH

We tested VIP effects directly on a trophoblast cell line (Swan 71 cells) and after co-culture with maternal peripheral blood mononuclear cells (PBMCs) as models of the feto-maternal dialogue. We also co-cultured maternal and paternal PBMCs to test effects of endogenous VIP on maternal alloresponses.

KEY RESULTS

Swan 71 cells express VPAC(1) receptors and VIP induced their proliferation and the expression of leukaemia inhibitor factor, a pro-implantatory marker. After interaction with trophoblast cells, VIP increased Foxp3, the proportion of CD4+CD25+Foxp3+ cells within maternal PBMCs and transforming growth factor beta expression. Also, during the trophoblast-maternal PBMCs interaction, VIP reduced pro-inflammatory mediators [interleukin (IL)-6, monocyte chemoattractant protein 1, nitric oxide], while increasing IL-10. Trophoblast cells produced VIP which dose-dependently suppressed allomaternal responses, accompanied by reduced expression of the T cell transcription factor, T-bet.

CONCLUSIONS AND IMPLICATIONS

Vasoactive intestinal peptide induced pro-implantatory markers and trophoblast cell proliferation, while controlling the initial pro-inflammatory response, by increasing maternal regulatory T cells and anti-inflammatory cytokines. As an autocrine regulatory peptide VIP might contribute to fetal survival through two mechanisms; a direct trophic effect on trophoblast cells and an immunomodulatory effect that favours tolerance to fetal antigens.

Interleukin-6 stimulates cell migration, invasion and integrin expression in HTR-8/SVneo cell line

Interleukin-6 (IL-6) is present in human endometrium throughout menstrual cycle and in pregnancy. Trophoblast also expresses IL-6. IL-6R and its associated signal transducer gp130 were found in trophoblast as well. IL-6 is generally assumed to be relevant for trophoblast invasion. This study was undertaken to determine influence of endogenous and externally added IL-6 on invasion and migration of first trimester of pregnancy trophoblast in vitro. Integrins alpha(5)beta(1) and alpha(1)beta(1) have been shown to play an important role in trophoblast invasion and the effect of IL-6 on the expression of these integrin subunits was studied. We are showing that in both isolated first trimester of pregnancy cytotrophoblast (CTB) and HTR-8/SVneo cell line IL-6 and IL-6R are present. The effect on migration was studied using cell wounding and migration test on HTR-8/SVneo cells. Effect of IL-6 and function blocking anti-IL-6 antibody in Matrigel invasion tests was studied on both cell types. The effect of IL-6 on integrin subunit expression was determined by cell-based ELISA and Western blot on HTR-8/SVneo cells. The results obtained show that exogenous IL-6 has stimulatory effect on cell migration in HTR-8/SVneo and invasion by both cell types. Function blocking anti-IL-6 inhibited unstimulated invasion by isolated first trimester cytotrophoblast and both cell migration and invasion in unstimulated HTR-8/SVneo. Integrin alpha(5) expression was stimulated by IL-6 to 134% (p<0.05), alpha(1) to 135% (p<0.005), and beta(1) to 134% (p<0.001) of control in cell-based ELISA, but also in Western blot. The data obtained show for the first time sensitivity of extravillous trophoblast cell line HTR-8/SVneo to IL-6, in addition to isolated first trimester cytotrophoblast. We conclude that both exogenous and endogenous IL-6 stimulate trophoblast cell migration and invasion, which may be partly attributable to stimulation of expression of the studied integrin subunits.

Society for Reproductive Biology Founders' Lecture 2009. Preparing fertile soil: the importance of endometrial receptivity

The human endometrium is receptive for implantation of a blastocyst for only 4–5 days in each menstrual cycle. Failure of implantation is a major reason for infertility in women and the inability to achieve endometrial receptivity is responsible for much of the failure of reproductive technologies. Endometrial receptivity requires changes in the uterine luminal and glandular cells, particularly in terms of their secretory capacity and altered expression of adhesion molecules. In parallel with these changes, decidualisation (differentiation) of the endometrial stroma is initiated in women during the receptive phase, regardless of the presence of a blastocyst. Increased leucocyte numbers are also important. The microenvironments provided by the endometrium during the receptive phase and that support implantation are highly complex and constantly changing as implantation progresses. The present review provides a comprehensive overview of the cellular and molecular events of human implantation. It also summarises work from our laboratories emphasising the functional importance of proprotein convertase 6, along with key cytokines (interleukin-11, leukaemia inhibitory factor, activin A) and chemokines (including CX3CL1 and CCL14), during implantation. Of particular importance is how these mediators contribute to receptivity and how they are disturbed in infertile women. Factors that are critical for uterine receptivity may also be manipulated to provide new contraceptive strategies for women.