Inverse regulation of the interferon-gamma receptor and its signaling in human endometrial stromal cells during decidualization

Analysis of interferon-γ receptor IFNGR1 and IFNGR2 expression and regulation at the maternal-conceptus interface and the role of interferon-γ on endometrial expression of interferon signaling molecules during early pregnancy in pigs

It has long been known that pig conceptuses produce interferon-γ (IFNG) at the time of implantation, but the role of IFNG and its mechanism of action at the maternal-conceptus interface are not fully understood. Accordingly, we analyzed the expression and regulation of IFNG receptors IFNGR1 and IFNGR2 in the endometrium during the estrous cycle and pregnancy in pigs. Levels of IFNGR1 and IFNGR2 messenger RNA (mRNA) expression changed in the endometrium, with the highest levels during mid pregnancy for IFNGR1 and on Day 12 of pregnancy for IFNGR2. The expression of IFNGR1 and IFNGR2 mRNAs was also detected in conceptuses during early pregnancy and chorioallantoic tissues during mid to late pregnancy. IFNGR1 and IFNGR2 mRNAs were localized to endometrial epithelial and stromal cells and to the chorionic membrane during pregnancy. IFNGR2 protein was also localized to endometrial epithelial and stromal cells, and increased epithelial expression of IFNGR2 mRNA and protein was detectable during early pregnancy than the estrous cycle. Explant culture studies showed that estrogen increased levels of IFNGR2, but not IFNGR1, mRNAs, while interleukin-1β did not affect levels of IFNGR1 and IFNGR2 mRNAs. Furthermore, IFNG increased levels of IRF1, IRF2, STAT1, and STAT2 mRNAs in the endometrial explants. These results in pigs indicate that IFNGR1 and IFNGR2 are expressed in a stage of pregnancy- and cell-type specific manner in the endometrium and that sequential cooperative action of conceptus signals estrogen and IFNG may be critical for endometrial responsiveness to IFNs for the establishment of pregnancy in pigs.

Investigation of Toll-Like Receptor-2 (2258G/A) and Interferon Gamma (+874T/A) Gene Polymorphisms among Infertile Women with Female Genital Tuberculosis

BACKGROUND

Toll-like receptor 2 (TLR2) and interferon-gamma (IFN-γ) coordinate with a diverse array of cellular programs through the transcriptional regulation of immunologically relevant genes and play an important role in immune system, reproductive physiology and basic pathology. Alterations in the functions of TLR2 2258G (guanine)/ A, IFN-γ (+874T/A) and signalling molecules that result from polymorphisms are often associated with susceptibility or resistance, which may, in turn, establish the innate host response to various infectious diseases. Presently, we proposed to investigate the risk of common single nucleotide polymorphism (SNP) of TLR2 and IFN-γ genes, for their effect on infertility in women with female genital tuberculosis (FGTB) and healthy women as controls.

METHODOLOGY/PRINCIPAL FINDINGS

Genotyping of TLR2 and IFN-γ gene polymorphisms was performed by amplification refractory mutation system multi-gene/multi-primer polymerase chain reaction followed by restriction fragment length polymorphism in 175 FGTB patients and 100 healthy control women (HCW). The TLR2 polymorphism [adenine (A) allele] was observed in 57.7 and 58.0% of FGTB patients and HCW, respectively. The IFN-γ (+874T/A) polymorphism (A allele) was significant in 74.3 and 71.0% of FGTB patients and HCW, respectively, while the odds ratios for the AA and TA genotypes for predisposition of FGTB were found to be 0.304 and 1.650 in HCW, respectively. The SNP of TLR2 was not associated with FGTB but the SNP of IFN-γ was found to be associated with mycobacteria infections and to induce infertility.

CONCLUSIONS/SIGNIFICANCE

At present, we hypothesize that infertile women with FGTB and HCW without tuberculosis (TB) have identical frequency of TLR variants, which may be adequate in the production of IFN-γ in response to Mycobacterium tuberculosis infections. Thus, the study appears to be the first of its kind reporting a mutation in the IFN-γ gene [+874 T (thymine) to A] responsible for susceptibility to TB infections and further inducing infertility.

Profiles of cytokines secreted by isolated human endometrial cells under the influence of chorionic gonadotropin during the window of embryo implantation

BACKGROUND

Several studies have indicated that human pre-implantation embryo-derived chorionic gonadotropin (hCG) may influence the implantation process by its action on human endometrial epithelial and stromal cells. Despite reports indicating that hCG acts on these cells to affect the production of several cytokines and growth factors (e.g., MIF, IGF-I, VEGF, LIF, IL-11, GMCSF, CXL10 and FGF2), our understanding of the integral influence of hCG on paracrine interactions between endometrial stromal and epithelial cells during implantation is very limited.

METHODS

In the present study, we examined the profile of 48 cytokines in the conditioned media of primary cell cultures of human implantation stage endometrium. Endometrial epithelial cells (group 1; n = 20), stromal cells (group 2; n = 20), and epithelial plus stromal cells (group 3; n = 20) obtained from mid-secretory stage endometrial samples (n = 60) were grown on collagen and exposed to different doses (0, 1, 10 and 100 IU/ml) of rhCG for 24 h in vitro. Immunochemical and qRT-PCR methods were used to determine cytokine profiles. Enrichment and process networks analyses were implemented using a list of cytokines showing differential secretion in response to hCG.

RESULTS

Under basal conditions, endometrial epithelial and stromal cells exhibited cell type-specific profiles of secreted cytokines. Administration of hCG (100 IU) resulted in significantly (P < 0.05) different cytokine secretion profiles indicative of macropinocytic transport (HGF, MCSF) in epithelial cells, signal transduction (CCL4, FGF2, IL-1b, IL-6, IL-17, VEGF) in stromal cells, and epithelial-mesenchymal transition (FGF2, HGF, IL-1b, TNF) in mixed cells. Overall, the administration of hCG affected cytokines involved in the immune response, chemotaxis, inflammatory changes, proliferation, cell adhesion and apoptosis.

CONCLUSIONS

CG can influence the function of the endometrium during blastocyst implantation via its differential action on endometrial epithelial and stromal cells. CG may also affect complex paracrine processes in the different endometrial cell types.

Interferon gamma contributes to preimplantation embryonic development and to implantation site structure in NOD mice

BACKGROUND

Pre-eclampsia, a syndrome usually accompanied by incomplete spiral arterial modification, occurs at an increased frequency in diabetic women. Hyperglycemia in non-obese type 1 diabetic (NOD) mice impairs gestational spiral arterial remodeling despite high local levels of interferon gamma (Ifng), the triggering cytokine in mice. Pregnancies in NOD.Ifng(-/-) mice were assessed to investigate this issue.

METHODS

Fecundity was assessed using the breeding history, flushing of preimplantation embryos and histological and morphometric studies of implantation sites in normoglycemic (n-) and hyperglycemic (d-) females of NOD.Ifng(-/-) and NOD genotypes.

RESULTS

NOD.Ifng(-/-) but not NOD mice are mostly infertile. In NOD.Ifng(-/-), copulation often does not result in a post-implantation pregnancy. Defective fertilization and delayed preimplantation development limit n-NOD.Ifng(-/-) fertility, and both mechanisms are exacerbated by hyperglycemia. At mid-gestation, implantation sites in n-NOD.Ifng(-/-) and n-NOD mice are histologically similar. However, in d-NOD.Ifng(-/-), there is minimal development of spiral arteries, hypertrophy of the myometrial region containing uterine Natural Killer (uNK) cells and a deficit in cytoplasmic granule formation in the uNK cells.

CONCLUSIONS

Ifng contributes to the success of fertilization and to the rate of preimplantation mouse embryo development in normogylcemic and hyperglycemic pregnancies. A physiological role for this cytokine in human preimplantation development merits investigation.

Heparin inhibits interferon-γ signaling in human endometrial stromal cells by interference with the cellular binding of interferon-γ

OBJECTIVE

To examine the impact of heparins on interferon-γ (IFN-γ) signaling in human endometrial stromal cells (ESCs) in vitro.

DESIGN

In vitro experiment.

SETTING

Research laboratory at a medical university center.

PATIENT(S)

Premenopausal women undergoing hysterectomy for benign reasons.

INTERVENTION(S)

The ESCs were isolated from hysterectomy specimens, decidualized in vitro using P and 17β-E(2), and incubated with recombinant IFN-γ, unfractionated heparin, and low molecular weight heparins (LMWHs).

MAIN OUTCOME MEASURE(S)

Interferon response factor 1 (IRF-1) and N-myc interactor (Nmi) messenger RNA (mRNA) were measured using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Phosphorylation of signal transducer and activator of transcription 1 (STAT-1) was detected by an in-cell Western assay, expression of the IFN-γ receptor by flow cytometry. Cell-bound IFN-γ was determined in lysates by an ELISA.

RESULT(S)

Heparin and LMWHs inhibit the IFN-γ-mediated induction of IRF-1, but not Nmi in undifferentiated and decidualized ESCs. The phosphorylation of signal transducer and activator of transcription 1 STAT-1 upon IFN-γ stimulation is inhibited as well. Heparin has no effect on the IFN-γ receptor in ESCs, but inhibits the binding of IFN-γ to the cells.

CONCLUSION(S)

Unfractionated heparin, as well as LMWHs, are able to inhibit IFN-γ signaling in human ESCs and therefore might be clinically interesting agents to modulate the actions of this proinflammatory cytokine at the implantation site.