Recombinant humanized type I collagen remodels decidual immune microenvironment at maternal-fetal interface by modulating Th17/Treg imbalance

Disruption of the extracellular matrix and dysregulation of the balance between Th17 and regulatory T cells are recognized as risk factors for recurrent spontaneous abortion (RSA). However, the interaction between matrix components and the Th17/Treg axis remains poorly elucidated. The result of this study revealed that the absence of type I collagen in the decidua is linked to Th17/Treg imbalance in RSA. Furthermore, we discovered that biomaterial recombinant humanized type I collagen (rhCOLI) promoted T cell differentiation into Tregs by inhibition the Notch1/Hes1 signaling pathway and enhanced the immunosuppressive function of Tregs, as indicated by increased secretion level of IL-10 and TGF-β. Importantly, this study is the first to demonstrate that rhCOLI can modulate the Th17/Treg imbalance, reduce embryo resorption rates, reshape the immune microenvironment at the maternal-fetal interface, and improve fertility in an RSA mouse model. Collectively, these findings suggest that type I collagen deficiency may contribute to, rather than result from, RSA, and propose a potential intervention for RSA using rhCOLI.

IL-2/JES6-1 Antibody Complex Expands the Maternal T-Regulatory Cell Pool and Alleviates Fetal Loss in Abortion-Prone Mice

Regulatory T (Treg) cells are essential for immune tolerance of embryo implantation, and insufficient Treg cells are implicated in early pregnancy loss. An abortion-prone mouse model was used to evaluate the utility of IL-2 complexed with JES6-1 anti-IL-2 antibody (IL-2/JES6-1) to boost uterine Treg cells and improve reproductive success. IL-2/JES6-1, but not IL-2/IgG control, administered in the periconception phase to CBA/J females mated with DBA/2 males elicited a greater than twofold increase in the proportion of CD4+ T cells expressing forkhead box P3 (FOXP3), and an increase in the ratio of FOXP3+ Treg cells/FOXP3- T conventional cells, in the uterus and its draining lymph nodes at embryo implantation that was sustained into midgestation. An attenuated phenotype was evident in both thymic-derived and peripheral Treg cells with elevated cytotoxic T-lymphocyte antigen-4, CD25, and FOXP3, indicating improved suppressive function, as well as increased proliferative marker Ki-67. IL-2/JES6-1 treatment reduced fetal loss from 31% to 10%, but this was accompanied by a 6% reduction in late gestation fetal weight, despite comparable placental size and architecture. Similar effects of IL-2/JES6-1 on Treg cells and fetal growth were seen in CBA/J females with healthy pregnancies sired by BALB/c males. These findings show that expanding the uterine Treg cell pool through targeting IL-2 signaling is a strategy worthy of further investigation for mitigating immune-mediated fetal loss.

Effect of Cyclosporine A on Th1/Th2 Cytokine Production by Decidual Stromal Cells Mediated by Trophoblast-derived Galectin-9

This study aimed to investigate the effect of cyclosporine A (CsA) on secretion of Th1 and Th2 cytokines by decidual stromal cells (DSCs) mediated by galectin (Gal)-9.HTR8/SVneo cells and primary trophoblasts were used for in vitro studies. Gal-9 expression was measured using quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, CsA was used to regulate Gal-9 expression in trophoblasts. DSCs were treated with trophoblast supernatant and changes in Th1 and Th2 cytokine levels were analyzed. Changes in DSC levels of the T-cell immunoglobulin mucin receptor 3 (TIM-3) levels in DSCs after treatment with Gal-9 were assessed. Western blotting and ERK and AKT inhibitors were used to assess the involvement of the corresponding signaling pathways. Gal-9 was expressed by both primary trophoblasts and HTR8/SVneo cells. CsA treatment increased Gal-9 secretion by trophoblasts, which in turn increased IL-6 (Th2 cytokine) and decreased TNF-α and IFN-γ (Th1 cytokines) secretion in DSCs. Upon downregulation of trophoblast Gal-9 secretion, DSCs secreted lower levels of Th2 cytokines and higher levels of Th1 cytokines, and the effect was reversed by addition of CsA. TIM-3 expression changed in parallel with Gal-9 secretion. CsA treatment upregulated expression of Gal-9 in trophoblasts, promoted secretion of Th2 cytokines, and inhibited secretion of Th1 cytokines via ERK signaling.

Identification of hub genes in placental dysfunction and recurrent pregnancy loss through transcriptome data mining: A meta-analysis

Recurrent pregnancy loss (RPL) is a condition characterized by the loss of two or more pregnancies before 20 weeks of gestation. The causes of RPL are complex and can be due to a variety of factors, including genetic, immunological, hormonal, and environmental factors. This transcriptome data mining study was done to explore the differentially expressed genes (DEGs) and related pathways responsible for pathogenesis of RPL using an Insilco approach. RNAseq datasets from the Gene Expression Omnibus (GEO) database was used to extract RNAseq datasets of RPL. Meta-analysis was done by ExpressAnalyst. The functional and pathway enrichment analysis of DEGs were performed using KEGG and BINGO plugin of Cytoscape software. Protein-protein interaction was done using STRING and hub genes were identified. A total of 91 DEGs were identified, out of which 10 were downregulated and 81 were upregulated. Pathway analysis indicated that majority of DEGs were enriched in immunological pathways (IL-17 signalling pathway, TLR-signalling pathway, autoimmune thyroid disease), angiogenic VEGF-signalling pathway and cell-cycle signalling pathways. Of these, 10 hub genes with high connectivity were selected (CXCL8, CCND1, FOS, PTGS2, CTLA4, THBS1, MMP2, KDR, and CD80). Most of these genes are involved in maintenance of immune response at maternal-fetal interface. Further, in functional enrichment analyses revealed the highest node size in regulation of biological processes followed by cellular processes, their regulation and regulation of multicellular organismal process. This in-silico transcriptomics meta-analysis findings could potentially contribute in identifying novel biomarkers and therapeutic targets for RPL, which could lead to the development of new diagnostic and therapeutic strategies for this condition.

Demystifying the landscape of endometrial immune microenvironment in luteal-phase from cuprotosis: Implications for the mechanism and treatment of RPL

BACKGROUND

Adaptive changes in the endometrial immune microenvironment during the luteal phase are essential for pregnancy, and their abnormalities are associated with recurrent pregnancy loss (RPL). Nevertheless, the specific mechanism is still unknown. Cuprotosis, an innovatively discovered type of programmed cell death, provides us with a pioneering perspective to decipher the landscape of luteal-phase endometrial immune microenvironment in RPL. This study aimed to analyze the immune landscape of luteal-phase endometrial microenvironment in RPL and explore the association of cuprotosis with it through integrative bioinformatics analysis.

METHODS

The microarrays involving the luteal phase endometrial tissue of RPL were obtained from the GEO database. Differentially expressed genes (DEGs) of RPL were screened and key modules were detected by WGCNA. GO, KEGG, and GSEA immune enrichment analyses were performed on the DEGs in the most relevant modules to RPL. Then, the endometrial immune microenvironment landscape of RPL was analyzed, including immune infiltration analysis and correlation analysis between immune cells or immune functions. The interaction of cuprotosis-related genes (CRGs), the expression level between groups, the immune localization and their correlation with immune cells and immune function were analyzed. LASSO regression and Nomogram evaluated the diagnostic value of immune-related CRGS in RPL. Functional enrichment analysis was performed on the RPL signature CRGs. And RPL samples were grouped according to the expression of 7 RPL signature CRGs through unsupervised clustering analysis. After that, we analyzed the expression level of CRGs and immune infiltration, as well as performed immune function enrichment analysis in subtypes. In addition, we also screened potential drugs that might act on CRGs to improve the pathological mechanism of RPL.

RESULTS

In this study, we uncovered that DEGs and genes in key modules derived from weighted gene co-expression network analysis (WGCNA) were involved in immune regulation. And the immune infiltration landscape of RPL was significantly different from healthy controls. Furthermore, six hub genes were screened from CRGs based on Cytohubba, and their expression profilings were verified in RPL and normal mouse samples. Besides, seven CRGs closely associated with the immune regulation of RPL were identified by Spearman correlation analysis, including SLC31A1, LIAS, DLD, DLAT, DBT, ATP7B, and ATP7A, named as immune-related CRGs. Furthermore, three subgroups clustered according to these seven genes showed significant differences in immune landscape, suggesting a remarkable effect of CRGs on immune regulation. Last but not least, we analyzed the regulation network of transcription factors, miRNAs, and CRGs, and screened potential compounds for the treatment of RPL by targeting CRGs.

CONCLUSIONS

The abnormal endometrial immune microenvironment in the luteal phase was associated with the pathomechanism of RPL, and cuprotosis was closely involved in the immune microenvironment in the luteal phase endometrium of RPL. Collectively, this study revealed the potential contribution of CRGs to the pathogenesis of RPL, providing a novel breakthroughs in insights into the pathogenesis, diagnosis, and treatment of RPL.

Prognostic model on pregnancy outcomes for women with recurrent spontaneous abortions treated with cyclosporin A: A single-institution experience

BACKGROUND

This study aimed to identify prognostic factors for pregnancy outcomes and construct a prognostic model for pregnancy outcomes in women with Recurrent Spontaneous Abortions (RSA) treated with cyclosporin A.

METHODS

A total of 154 RSA patients treated with cyclosporin A between October 2016 and October 2018 were retrospectively recruited. Multivariate logistic regression was applied to identify the prognostic factors for pregnancy success in RSA women treated with cyclosporin A. The Receiver Operating Characteristic (ROC) curve was applied to construct prognostic value, and the prognostic performance was assessed using area under the ROC.

RESULTS

After adjusting potential confounding factors, the authors noted increased age (OR = 0.771; 95 % CI 0.693‒0.858; p < 0.001) and positive antinuclear antibodies (OR = 0.204; 95 % CI 0.079‒0.526; p = 0.001) were associated with a reduced incidence of pregnancy success, while positive anti-β2 glycoprotein-I-antibody (OR = 21.941; 95 % CI 1.176‒409.281; p = 0.039) was associated with an increased incidence of pregnancy success after treated with cyclosporin A. The AUC of combining these variables for predicting pregnancy failure was 0.809 (95 % CI 0.735‒0.880).

CONCLUSIONS

This study systematically identified the prognostic factors for pregnancy success in women treated with cyclosporin A, and the constructed prognostic model based on these factors with relatively higher prognostic value. Further large-scale prospective studies should be performed to validate the prognostic value of the constructed model.

Cyclophilin A as a Pro-Inflammatory Factor Exhibits Embryotoxic and Teratogenic Effects during Fetal Organogenesis

The precise balance of Th1, Th2, and Th17 cytokines is a key factor in successful pregnancy and normal embryonic development. However, to date, not all humoral factors that regulate and influence physiological pregnancy have been completely studied. Our data here pointed out cyclophilin A (CypA) as the adverse pro-inflammatory factor negatively affecting fetal development and associated with pregnancy complications. In different mouse models in vivo, we demonstrated dramatic embryotoxicity and teratogenicity of increased CypA levels during pregnancy. Using generated transgenic models, we showed that CypA overexpression in fetal tissues induced the death of all transgenic fetuses and complete miscarriage. Administration of recombinant human CypA in a high dose to pregnant females during fetal organogenesis (6.5-11.5 dpc) exhibited teratogenic effects, causing severe defects in the brain and bone development that could lead to malformations and postnatal behavioral and cognitive disorders in the offspring. Embryotoxic and teratogenic effects could be mediated by CypA-induced up-regulation of M1 macrophage polarization via activation of the STAT1/3 signaling pathways. Here, we propose secreted CypA as a novel marker of complicated pregnancy and a therapeutic target for the correction of pregnancy complications.

IGFBP7 enhances trophoblast invasion via IGF-1R/c-Jun signaling in unexplained recurrent spontaneous abortion

In brief

Insufficient trophoblast invasion at the maternal-fetal interface contributes to abortion-prone pregnancy. Our study shows that decreased levels of IGFBP7 in unexplained recurrent spontaneous abortion (URSA) trophoblast cells inhibit MMP2 and Slug expression as well as trophoblast invasion, suggesting that IGFBP7 should be considered a potential therapeutic protein target in URSA.

Abstract

Insufficient trophoblast invasion at the maternal-fetal interface contributes to abortion-prone pregnancy. Cyclosporine A (CsA) can exert therapeutic effects on URSA by promoting trophoblast invasion. A previous study showed decreased expression of insulin-like growth factor-binding protein 7 (IGFBP7) in the sera of recurrent spontaneous abortion patients. However, the role of IGFBP7 in URSA remains unknown. The aim of this study was to determine whether IGFBP7 modulates trophoblast invasion in URSA and the underlying molecular mechanisms. We found that IGFBP7 was expressed at lower levels in villous specimens from URSA patients. Manipulating IGFBP7 expression significantly affected the MMP2 and Slug expression in HTR-8/SVneo cells as well as trophoblast invasion in vitro. Inactivation of IGF-1R by IGFBP7 was observed, and IGF-1R inhibition increased the IGFBP7-induced MMP2 and Slug expression in HTR-8/SVneo cells. Moreover, the level of c-Jun was significantly upregulated in the URSA group. Silencing IGFBP7 increased the binding of downstream c-Jun to the MMP2 and Slug promoter regions in HTR-8/SVneo cells, thus suppressing transcription. In addition, increased expression of IGFBP7 in HTR-8/SVneo cells was observed upon CsA treatment. Knockdown of IGFBP7 inhibited the CsA-enhanced MMP2 and Slug expression in HTR-8/SVneo cells. Our results suggest that in normal pregnancy, IGFBP7 induces MMP2 and Slug expression via the IGF-1R-mediated c-Jun signaling pathway, thereby promoting trophoblast invasion. IGFBP7 depletion in URSA inhibits MMP2 and Slug expression as well as trophoblast invasion. Moreover, IGFBP7 participates in CsA-induced trophoblast invasion, suggesting that IGFBP7 is a potential therapeutic target for URSA.

Zika virus causes placental pyroptosis and associated adverse fetal outcomes by activating GSDME

Zika virus (ZIKV) can be transmitted from mother to fetus during pregnancy, causing adverse fetal outcomes. Several studies have indicated that ZIKV can damage the fetal brain directly; however, whether the ZIKV-induced maternal placental injury contributes to adverse fetal outcomes is sparsely defined. Here, we demonstrated that ZIKV causes the pyroptosis of placental cells by activating the executor gasdermin E (GSDME) in vitro and in vivo. Mechanistically, TNF-α release is induced upon the recognition of viral genomic RNA by RIG-I, followed by activation of caspase-8 and caspase-3 to ultimately escalate the GSDME cleavage. Further analyses revealed that the ablation of GSDME or treatment with TNF-α receptor antagonist in ZIKV-infected pregnant mice attenuates placental pyroptosis, which consequently confers protection against adverse fetal outcomes. In conclusion, our study unveils a novel mechanism of ZIKV-induced adverse fetal outcomes via causing placental cell pyroptosis, which provides new clues for developing therapies for ZIKV-associated diseases.

Improved pregnancy outcomes of cyclosporine A on patients with unexplained repeated implantation failure in IVF/ICSI cycles: A retrospective cohort study

PROBLEM

Repeated implantation failure (RIF) is a daunting obstacle restricting the further improvement of embryo implantation rate (IR) and live birth rate (LBR). The beneficial effect of cyclosporine A (CsA) on reproductive outcomes of unexplained RIF(URIF) was explored after de novo embryo transfer (ET).

METHOD OF STUDY

A retrospective cohort study was conducted, comparing pregnancy outcomes of 146 cycles (CsA group, n = 62; control group, n = 84) at the IVF center of Suzhou Municipal Hospital from April 2016 to March 2020.

RESULTS

Baseline and transfer cycle characteristics of participants were comparable between groups. Overall, CsA exerted obvious improvement on IR (51.16% vs 31.97%, P = .006), clinical pregnancy rate (CPR) (58.06% vs 38.10%, P = .017), and LBR (48.39% vs 32.14%, P = .047). Especially, CsA showed remarkably enhancement on IR (41.38% vs 14.63%, P = .012), CPR (47.62% vs 17.24%, P = .021) of non-high quality embryos. No difference in obstetric and pediatric complications was observed, and no birth defects were reported under CsA application. CsA was found to be a predictor of clinical pregnancy [fine adjusted OR 2.360, 95 % CI 1.165-4.781; P = .017] and live birth [fine adjusted OR 2.339, 95% CI 1.124-4.867; P = .023] for multivariate logistic regression. Not surprisingly, the number of high quality embryos should also be considered as an independent predictor for clinical pregnancy [fine adjusted OR 1.637,95%CI 1.027-2.609; P = .038] and live birth [fine adjusted OR 1.890, 95% CI 1.165-3.068; P = .010].

CONCLUSION

CsA application in patients with URIF promotes the pregnancy outcomes and does not increase the risk of obstetric and pediatric complications.

Next generation of immune checkpoint molecules in maternal-fetal immunity

Successful pregnancy is a unique situation requires the maternal immune system to recognize and tolerate a semi-identical fetus and allow normal invasion of trophoblast cells. Although efforts have been made, the deep mechanisms of the maternal-fetal crosstalk have not yet been fully deciphered. Immune checkpoint molecules (ICMs) are a group of negative modulators of the immune response that avoid immune damage. They have been extensively studied in the fields of oncology and transplantation, while the latest evidence suggests that they are closely associated with pregnancy outcomes via multiple inhibitory mechanisms. Although studies have mostly demonstrated the regulatory role of the well-known PD-1, CTLA-4 at the maternal-fetal interface, what is unique about the newly discovered multiple ICMs remains a mystery. Here, we review the latest knowledge on ICMs, focusing on the first generation of checkpoints (PD-1, CTLA-4) and the next generation (Tim-3, Tigit, Lag-3, VISTA) highlighting their immunoregulatory roles in maternal-fetal tolerance and decidual vascular remodeling, and their involvement in pathological pregnancies. The content covers three aspects: the characteristics they possess, the dynamic expression profile of their expression at the maternal-fetal interface, and their involvement in pathological pregnancy. In immunotherapy strategies for pregnancy complications, upregulation of immune checkpoints may play a role. Meanwhile, the impact on pregnancy outcomes when using ICMs in clinical cancer treatment during pregnancy is a topic worth exploring. These may serve as a guide for future basic research and clinical applications of maternal-fetal immunity.

Cyclosporine A to Treat Unexplained Recurrent Spontaneous Abortions: A Prospective, Randomized, Double-Blind, Placebo-Controlled, Single-Center Trial

Background

The World Health Organization (WHO) has defined Unexplained Recurrent Spontaneous Abortion (URSA) as three and more consecutive miscarriages before the 20th week of gestation. To date, empiric therapy for patients with unexplained recurrent pregnancy loss (URPL) is not precise. Studies have shown that URSAs are associated with Th1/Th2 and Th17/Treg immune imbalances at the maternal-fetal interface. The immunosuppressant cyclosporine A (CsA) is widely used in patients with organ transplantation or autoimmune diseases, and it has a good safety profile in pregnant women. However, high-quality evidence for CsA treatment of URSAs is lacking. Our purpose with this study is to evaluate the efficacy and safety of CsA for improving pregnancy outcomes in patients with URSAs and to explore the role of CsA in regulating the immune balance.

Methods/Design

We expect to officially initiate our study at the Taizhou People's Hospital in March 2022. We defined the live birth rate as the primary outcome, and the secondary outcomes include the rates of successful pregnancy, miscarriage, pregnancy complications, and adverse pregnancy outcomes, and newborn birth weights. Patients who meet URSA eligibility criteria will be randomized in a 1:1 ratio into either a study group receiving CsA 2 weeks after fertilization or a control group receiving placebo at 2 weeks after fertilization (the women in both groups will receive the relevant treatment for 6 months). In addition, we will collect peripheral blood samples of the participants before and after the treatments, and we will isolate mononuclear cells and measure cytokine levels (IFN-γ, TNF-α, IL-2, IL-10, IL-6, IL-4) and Th1/Th2, Th17/Treg ratios.

Discussion

This is the first randomized controlled trial to evaluate the clinical and immunomodulatory effects of CsA on the pregnancy outcomes of women with URSA and our results will provide evidence to evaluate the use of CsA as a treatment for women with URSAs.

Cyclosporin A alleviates trophoblast apoptosis and senescence by promoting autophagy in preeclampsia

INTRODUCTION

Abnormal extravillous trophoblast (EVT) function is closely related to preeclampsia (PE) and may be caused by inadequate autophagy, apoptosis, and senescence. Cyclosporin A (CsA) is an effective immunosuppressant that has been reported to stimulate autophagy and exert benign biological effects on EVTs. Therefore, we hypothesized that CsA may display therapeutic efficacy against PE by activating autophagy.

METHODS

We established the nitro-l-arginine methyl ester (l-NAME)-induced preeclamptic mice model and a hypoxia-reoxygenation (H/R) model in vitro. The effects of CsA on autophagy were evaluated by western blotting (WB). The effects of CsA on apoptosis were analyzed by Hematoxylin-eosin (H&E) staining, cell apoptosis assay and WB. Senescence-associated β-galactosidase (SA-β-gal) staining, RT-qPCR and WB were used to examine the senescence level. RT-qPCR were used to detect the senescence-associated secretory phenotype (SASP) level. DCFH-DA fluorescent probe, dihydroethidium (DHE) staining and mitochondrial membrane potential (ΔΨm) were used to detect senescence-associated mitochondrial dysfunction (SAMD).

RESULTS

CsA alleviated PE-like symptoms and reduced placental necrosis and senescence in mice injected with l-NAME. CsA ameliorated placental SASP and SAMD level induced by l-NAME. CsA also upregulated the expression of autophagic proteins in mouse placentas disrupted using l-NAME. In vitro, we found that CsA reversed H/R-induced apoptosis and senescence, as well as decreasing SASP and SAMD levels and upregulating autophagic proteins levels. Notably, 3-methyladenine (3-MA), an early phase inhibitor of autophagosome formation, abolished the protective effects of CsA against H/R.

DISCUSSION

CsA may display some therapeutic effects against PE by activating autophagy in vivo and in vitro.

Regulation of the innate immune cells during pregnancy: An immune checkpoint perspective

The foetus can be regarded as a half‐allograft implanted into the maternal body. In a successful pregnancy, the mother does not reject the foetus because of the immune tolerance mechanism at the maternal‐foetal interface. The innate immune cells are a large part of the decidual leukocytes contributing significantly to a successful pregnancy. Although the contributions have been recognized, their role in human pregnancy has not been completely elucidated. Additionally, the accumulated evidence demonstrates that the immune checkpoint molecules expressed on the immune cells are co‐inhibitory receptors regulating their activation and biological function. Therefore, it is critical to understand the immune microenvironment and explore the function of the innate immune cells during pregnancy. This review summarizes the classic immune checkpoints such as PD‐1, CTLA‐4 and some novel molecules recently identified, including TIM‐3, CD200, TIGIT and the Siglecs family on the decidual and peripheral innate immune cells during pregnancy. Furthermore, it emphasizes the role of the immune checkpoint molecules in pregnancy‐associated complications and reproductive immunotherapy.

Efficacy of Intrauterine Perfusion of Cyclosporin A for Intractable Recurrent Spontaneous Abortion Patients With Endometrial Alloimmune Disorders: A Randomized Controlled Trial

Objective

To explore the therapeutic efficacy of intrauterine perfusion of cyclosporin A (CsA) in intractable recurrent spontaneous abortion (RSA) patients with endometrial alloimmune dysfunction.

Methods

This is a randomized controlled trial (RCT) of patients with intractable RSA with endometrial alloimmune disorders. A total of 201 women were enrolled, all of whom had at least 3 serial abortions and endometrial alloimmune dysfunction. Participants were randomly assigned to two groups. The CsA group (n = 101) received intrauterine infusion of 250 mg CsA on the 3rd and 7th days after menstruation for 2 menstrual cycles, while the placebo group (n = 100) received placebo. The birth of healthy, deformity-free babies was the main study outcome.

Results

In total, 75 (74.26%) women in the CsA group and 59 (59.00%) women in the placebo group gave birth to healthy babies [P = 0.01, OR = 2.01; 95% CI (1.10∼3.65)]. Compared to the placebo group, the CsA group had dramatically lower endometrial CD56⁺ cell and CD57⁺ cell concentrations at the luteal phase of the second menstrual cycle (P < 0.05).

Conclusion

Intrauterine perfusion of CsA was confirmed to be a promising approach for the treatment of intractable alloimmune RSA.

Impacts of Cyclosporin A on clinical pregnancy outcomes of patients with a history of unexplained transfer failure: a retrospective cohort study

BACKGROUND

A rapid development in assisted reproductive technology (ART) has led to a surge in its popularity among target couples. However, elucidation on the molecular mechanism and effective solutions for a common problem posed by ART, namely transfer failure, is still lacking. The new therapeutic potential of cyclosporin A (CsA), a typical immunosuppressant widely used in the treatment of rejection after organ transplantation, in recurrent pregnancy loss (RPL) patients may inspire some novel transfer failure therapies in the future. To further explore the clinical effects of CsA, this study investigated whether its application can improve clinical pregnancy outcomes in patients with a history of unexplained transfer failure in frozen-thawed embryo transfer (FET) cycles.

METHODS

Data from a retrospective cohort investigation (178 frozen-thawed embryo transfer cycles in 178 patients) were analysed using binary logistic regression to explore the relationship between CsA treatment and clinical pregnancy outcomes; the odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated as a measure of relevancy. Implantation rate was the main outcome measure.

RESULTS

There was no difference in the fine adjusted OR (95 % CI) of the implantation rate [1.251 (0.739-2.120)], clinical pregnancy rate [1.634 (0.772-3.458)], chemical pregnancy rate [1.402 (0.285-6.909)], take-home baby rate [0.872 (0.423-1.798)], multiple births rate [0.840 (0.197-3.590)], preterm birth [1.668 (0.377-7.373)], abnormal birth weight [1.834 (0.533-6.307)] or sex ratio [0.956 (0.339-2.698)] between the CsA-treated group and control group. No birth defects were observed in the present study.

CONCLUSIONS

Although CsA does not affect infant characteristics, it has no beneficial effects on the clinical pregnancy outcomes in patients with a history of unexplained transfer failure in FET cycles.

Diet Supplementation with Pomegranate Peel Improves Embryonic Survival in a Mouse Model of Early Pregnancy Loss

The peel of pomegranate fruit is a rich source of polyphenolic compounds with powerful antioxidant properties. We evaluated the therapeutic potential of pomegranate peel (PP) in the prevention of early pregnancy loss in a mouse model of embryonic mortality and abortion (female CBA/J x male DBA/2). CBA/J mice were divided into 3 groups: mice in control group (CONT group) were fed a standard diet, whereas mice in groups 2 and 3 were fed a standard diet supplemented with 1% PP (PP1% group) and 5% PP (PP5% group), respectively. All the mice were fed their diets for 10 days before mating and continued with the same diets for a further 14 days after mating. At day 14 of pregnancy the female mice were sacrificed and the placentas and maternal livers were harvested for measurement of the content of thiols and thiobarbituric acid reactive substances (TBARS), as biomarkers of oxidative stress, and the enzymatic activities of total superoxide dismutase (TSOD), copper/zinc SOD (SOD1), manganese SOD (SOD2), selenium glutathione peroxidase (GPX) and glutathione reductase (GR). Diet supplemented with 5% PP improved embryonic survival and reduced embryonic mortality from 28.2% (CONT) to 8.5% (PP5%). This was accompanied by increased activities of placental TSOD, SOD1 and SOD2, and thiol content. Diet supplemented with 5% PP also reduced placental oxidative stress as demonstrated by a decrease of placental TBARS content. This study highlights the potential of interventions with PP-supplemented diet before and during early pregnancy, in order to ameliorate embryonic survival and prevent early pregnancy loss.

Th17/Treg-cell balance in the peripheral blood of pregnant females with a history of recurrent spontaneous abortion receiving progesterone or cyclosporine A

A successful pregnancy requires the maternal immune system to accept a fetus expressing allogeneic paternal antigens and provide competent responses to infections. Accordingly, maternal-fetal immune abnormalities may have an important role in the development of recurrent spontaneous abortion (RSA). Ever since the establishment of the association between immunologic abnormalities and RSA, various types of immune therapy to restore normal immune homeostasis have been increasingly developed. Although previous studies have focused on the maternal-fetal interface, non-invasive examination is of great importance in clinical practice. The present study investigated the balance between type-17 T-helper (Th17) and T-regulatory (Treg) cells in the peripheral blood to improve the current understanding of the pathogenesis of RSA. Imbalances in Th17/Treg cells and associated molecular profiles were observed in patients with RSA. Furthermore, it was determined that the immunosuppressant cyclosporine A reduced the proportion of Th17 cells and promoted Treg-cell dominance by upregulating the expression of co-inhibitory molecules in pregnant females with a history of RSA. Progesterone, the traditional maternal-care drug, also had a certain immunomodulatory role through restoring the levels of several co-inhibitory molecules (including T-cell immunoglobulin mucin family member-3, programmed cell death-1 and cytotoxic T-lymphocyte associated protein-4) in the treatment of RSA. Changes in these immune molecules within the maternal peripheral blood may be indicators for monitoring pregnancy and prediction of RSA.

Cyclosporin A protects JEG-3 cells against oxidative stress-induced apoptosis by inhibiting the p53 and JNK/p38 signaling pathways

BACKGROUND

Trophoblast cells are required for the establishment of pregnancy and fetal development. Apoptosis is an essential feature for trophoblast invasion. Uncontrolled trophoblast apoptosis is related to some complicate pregnancies. Oxidative stress (OS) is an important inducer of trophoblast apoptosis. Cyclosporin A (CsA) has been shown to promote the activity of trophoblast cells and reduce OS-induced oxidative injury. We investigated the role and mechanism of CsA in oxidative stress-induced trophoblast cell apoptosis.

METHODS

JEG-3 cells were cocultured with H₂O₂ and CsA. Cell viability and morphology were measured by MTT assay and DAPI staining. Cell apoptosis was tested with annexin V/PI staining. The expression of Bcl-2-associated X protein (Bax), B-cell lymphoma/leukemia-2 (Bcl-2), cleaved poly (ADP-ribose) polymerase (PARP) and pro-caspase-3 was assayed by western blotting. The protein expression and phosphorylation of p53 and mitogen-activated protein kinase (MAPK) kinases (JNK, ERK1/2 and p38) were examined by western blotting.

RESULTS

CsA increased the viability, alleviated morphological injury and reduced cell apoptosis of the H₂O₂-treated JEG-3 cells. CsA also attenuated the activation of p53, decreased the expression of Bax and cleavage of PARP, and increased the expression of Bcl-2 and pro-caspase-3 in the JEG-3 treated with H₂O₂. Furthermore, CsA reduced the activation of JNK and P38 but had no significant effect on the activation of extracellular signal-regulated kinase 1/2 (ERK1/2) in the H₂O₂-treated JEG-3 cells. Promoting the activation of JNK and p38 impaired the protective effect of CsA on OS-induced trophoblast apoptosis.

CONCLUSIONS

These results suggested that CsA protected trophoblast cells from OS-induced apoptosis via the inhibition of the p53 and JNK/p38 signaling pathways.

Cyclosporin A ameliorates eclampsia seizure through reducing systemic inflammation in an eclampsia-like rat model

Our previous studies have shown that the maternal hyperinflammatory response in pre-eclampsia lowered the eclampsia-like seizure threshold. Cyclosporin A (CsA), which is an effective immunosuppressant, could attenuate the inflammatory responses in LPS-induced pre-eclampsia rats. Here, we hypothesized that CsA may ameliorate seizure severity through reducing systemic inflammation in pre-eclampsia/eclampsia. In the current study, the effects of CsA on pre-eclampsia manifestation, eclampsia-like seizure activities and systemic inflammation were examined in a pre-eclampsia model. Pregnant rats were given an intraperitoneal injection of the epileptogenic drug pentylenetetrazol (PTZ) following a tail vein injection of lipopolysaccharide to establish the eclampsia-like seizure model. CsA (5 mg/kg) was administered intravenously through the tail after LPS infusion. Mean systolic blood pressure and proteinuria in pre-eclampsia were detected. After PTZ injection, seizure activity was assessed, inflammatory responses were determined and pregnancy outcomes were analyzed. The results showed that CsA treatment significantly decreased blood pressure and proteinuria and increased the fetal and placental weight (P < 0.01). Meanwhile, CsA treatment significantly reduced serum IL-1β, TNF-α, and IL-17 levels (P < 0.01), decreased the seizure scores and prolonged the latency to seizure (P < 0.01). CsA effectively attenuated pre-eclampsia manifestation and eclampsia-like seizure severity. In addition, CsA treatment significantly reduced the inflammatory cytokine levels and improved pregnancy outcomes following eclampsia-like seizures. The decreased inflammatory cytokines in pre-eclampsia are coincident with attenuated pre-eclampsia manifestation after CsA treatment, suggesting that CsA treatment might decrease the eclampsia-like seizure severity through decreasing systemic inflammation in pre-eclasmpsia/eclampsia.

Cyclosporin A protects trophoblasts from H2O2-induced oxidative injury via FAK-Src pathway

Oxidative stress is associated with functional disorder of trophoblast cells. Our previous studies have demonstrated that cyclosporin A (CsA) promotes the activity of normal human trophoblast cells. We further investigated the role and mechanism of CsA on oxidative stress in trophoblast cells. JEG-3 cells were co-cultured with H₂O₂ and CsA. Cell viability and morphology were measured by MTT assay and inverted microscope. Reactive oxygen species (ROS) was analyzed by fluorescence microscopy. Cell mitochondrial membrane potential (MMP) was determined by flow cytometric analysis. Malondialdehyde (MDA) production, superoxide dismutase (SOD) and catalase (CAT) activities were examined using colorimetric assays. The expression and phosphorylation of FAK and Src kinase proteins were examined by western blotting. CsA increased JEG-3 cell viability and reduced the morphologic injury induced by H₂O₂ treatment. CsA decreased ROS and MDA production, increased SOD and CAT activities, and restored the MMP of H₂O₂ treated JEG-3 cells. CsA administration suppressed H₂O₂-induced reduction of FAK and Src phosphorylation. Blocking the activation of FAK or Src attenuated the protective effect of CsA on JEG-3 cells in H₂O₂-induced oxidative injury. CsA protects JEG-3 cells from H₂O₂-induced oxidative injury, and the FAK/Src signaling pathway plays an important role in this process.

Bioinformatics Analysis of Differentially Expressed Genes, Methylated Genes, and miRNAs in Unexplained Recurrent Spontaneous Abortion

Approximately half of the unexplained recurrent spontaneous abortions remain unexplained (URSAs). We aimed to provide novel insights into the biological characteristics and related pathways of differentially expressed genes (DE-genes), DE-methylated genes, and DE-miRNAs in URSA, and construct a molecular miRNAs-mRNAs network. Four data sets (GSE22490, GSE121950, GSE73025, and GSE43256) were gained from GEO data sets. We identified the DE-genes, DE-methylated genes, and DE-miRNAs using the LIMMA package in R software. Function and enrichment analyses were conducted using DAVID. A protein-protein network was performed by STRING. We predicted the target genes of DE-miRNA using DIANA-microT-CDS. Then, we constructed miRNAs-mRNAs network. There were 137 genes that overlapped in two expression profile data sets (GSE121950 and GSE22490). We found 10 overlapping DE-methylated genes and DE-genes with opposite expression alteration trends. All those 10 genes were hypermethylated lowly expressed genes. Pathway analysis illustrated that DE-genes were enriched in osteoclast differentiation, leishmaniasis, NF-kappa B signaling pathway, Toll-like receptor signaling pathway, and tuberculosis. Based on protein-protein interaction analysis, TLR8, TLR2, CD86, TLR4, IL10, CD163, FCGR1A, CXCL8, FCGR3A, HCK, PLEK, and MNDA were identified as hub genes for DE-genes. We screened out 47 DE-miRNAs and 42 overlapping DE-genes between predicted target genes of DE-miRNAs and the 137 DE-genes. We then constructed miRNAs-mRNAs network. This study identified several genes and miRNAs involved in the development and progression of URSA, including FCGR1A, FCGR3A, CXCL8, HCK, PLEK, IL10, hsa-miR-498, and hsa-miR-4530. Although further in vivo and in vitro validations are required, our results may provide a theoretical basis for future studies.

Immune Checkpoint Molecules in Reproductive Immunology

Immune checkpoint molecules, like CTLA-4, TIM-3, PD-1, are negative regulators of immune responses to avoid immune injury. Checkpoint regulators are thought to actively participate in the immune defense of infections, prevention of autoimmunity, transplantation, and tumor immune evasion. Maternal-fetal immunotolerance represents a real immunological challenge for the immune system of the mother: beside acceptance of the semiallogeneic fetus, the maternal immune system has to be prepared for immune defense mostly against infections. In this particular situation, the role of immune checkpoint molecules could be of special interest. In this review, we describe current knowledge on the role of immune checkpoint molecules in reproductive immunology.

Placenta immune infiltrates and perinatal outcomes

Pregnancy is a state of immunotolerance and loss of this immunotolerance may lead to fetal rejection, pregnancy complications, and neonatal complications. Immunobiology of pregnancy is complex and involves unique immune cell populations specific to pregnancy, changes in mucosal immune cells and peripheral immune system, and reciprocal adaptations between the mother and the fetus. The mechanisms required for sustaining a healthy feto-placental barrier and a healthy pregnancy such as activation of regulatory immune responses with a predominance of regulatory T cells lead to immune evasion and propagation of cancer. It is intriguing to note that the immune pathways which are effective in limiting or eliminating cancer form the very basis for loss of feto-maternal tolerance. In this article, we aim to compare and contrast immunobiology of healthy and pathological pregnancies mirroring with cancer immunobiology with a focus on immune checkpoint receptors.

Expression of E2A in mid-secretory endometrium of women suffering from recurrent miscarriage

E2A is involved in promoting forkhead box P3 (FOXP3) and retinoid-related orphan receptor gamma t (RORγt) gene transcription, which are pivotal transcription factors of T regulatory cells and Th17 cells, respectively. Little is known about the involvement of E2A in pregnancy process. This study aimed to investigate the expression of E2A, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), and Foxp3 in luteal phase endometrium of women suffering recurrent miscarriage (RM) (n=21) and control group (n=11) by immunohistochemistry, with the Vectra® automated quantitative pathology imaging system for analysis. The percentage of E2A+ cells and CTLA-4+ cells was significantly higher in the endometrium of women with RM than in the controls. There was positive correlation between E2A and CTLA-4 (r=0.523, P=0.002), E2A and FOXP3 (r=0.380, P=0.032), and FOXP3 and CTLA-4 (r=0.625, P=0.000) in the mid-secretory phase of endometrium for all subjects. It was concluded that the abnormal expression of endometrial E2A existed in mid-secretory endometrium of women with RM, and there was a positive correlation between E2A and FOXP3, and E2A and CTLA-4, suggesting the possible regulation role of E2A involved in regulating endometrium receptivity.

Kidney-Replenishing Herb Induces SOCS-3 Expression via ERK/MAPK Pathway and Improves Growth of the First-Trimester Human Trophoblast Cells

Kidney-replenishing herb is a traditional medicine formula in China which has been widely used for clinical treatment of recurrent miscarriage. Our previous study showed that Kidney-replenishing herb could promote proliferation and inhibit apoptosis of the human first-trimester trophoblasts. In the present study, we further explored the potential mechanism and signal pathway of Kidney-replenishing herb on human trophoblast cells. Our research showed that Kidney-replenishing herb stimulated proliferation and reduced apoptosis of human trophoblast cells in vitro, and this appeared to be positive correlation with SOCS-3 transcription, suggesting that Kidney-replenishing herb regulated biological functions of human trophoblast cells by inducing SCOS-3 expression. Furthermore, the Kidney-replenishing herb treatment stimulated the phosphorylation of ERK1/2, and blocking the signaling pathway by mitogen-activated protein MAPK (MEK) inhibitor, U0126, inhibited Kidney-replenishing herb-induced SOCS-3 transcription, depressed proliferation, and promoted apoptosis of human trophoblasts. Kidney-replenishing herbs still induced ERK1/2 phosphorylation after SOCS-3 siRNA silence. Overexpression of SOCS-3 stimulated the proliferation of trophoblast. These findings suggest that SOCS-3 expression is induced by Kidney-replenishing herbs via activation of MAPK pathways, and this may possibly be involved in promoting human trophoblast cells growth which is contributed to embryo development.

Cellular Dynamics of Mouse Trophoblast Stem Cells: Identification of a Persistent Stem Cell Type

Mouse trophoblast stem cells (TSCs) proliferate indefinitely in vitro, despite their highly heterogeneous nature. In this study, we sought to characterize TSC colony types by using methods based on cell biology and biochemistry for a better understanding of how TSCs are maintained over multiple passages. Colonies of TSCs could be classified into four major types: type 1 is compact and dome-shaped, type 4 is flattened but with a large multilayered cell cluster, and types 2 and 3 are their intermediates. A time-lapse analysis indicated that type 1 colonies predominantly appeared after passaging, and a single type 1 colony gave rise to all other types. These colony transitions were irreversible, but at least some type 1 colonies persisted throughout culture. The typical cells comprising type 1 colonies were small and highly motile, and they aggregated together to form primary colonies. A hierarchical clustering based on global gene expression profiles suggested that a TSC line containing more type 1 colony cells was similar to in vivo extraembryonic tissues. Among the known TSC genes examined, Elf5 showed a differential expression pattern according to colony type, indicating that this gene might be a reliable marker of undifferentiated TSCs. When aggregated with fertilized embryos, cells from types 1 and 2, but not from type 4, distributed to the polar trophectoderm in blastocysts. These findings indicate that cells typically found in type 1 colonies can persist indefinitely as stem cells and are responsible for the maintenance of TSC lines. They may provide key information for future improvements in the quality of TSC lines.

The effect of single course high dose dexamethasone on CD28/CTLA-4 balance in the treatment of patients with newly diagnosed primary immune thrombocytopenia

To evaluate the effect of a single course of high dose dexamethasone (HD-DXM) on CD28 and CTLA-4 expression in patients with newly-diagnosed primary immune thrombocytopenia (ITP). Twenty-8 ITP patients (18 females and 10 males, age range 18–65 years, median age 38.5 years) enrolled in this study and 26 healthy volunteers (19 women and 7 men, age range 16–66 years, median age 37 years) served as a control group. The patients were treated with HD-DXM (40 mg/day) for 4 consecutive days. CD28 and CTLA-4 expression was assessed by flow cytometry once-monthly for 6 months. Plasma levels of the cytokines IFN-γ and IL-10 were determined by enzyme-linked immunosorbent assay. One month after treatment, a platelet response was observed in 23 (82%) of the patients. The response rates over the next 5 months were 71%, 57%, 53%, 46%, and 39%, chronologically. We observed a significant decrease in CD28 expression after the first month (34.7 ± 4.8% vs. 44.5 ± 4.4% before treatment), after which the CD28 levels gradually increased. In contrast, CTLA-4 expression increased after the first month (3.2 ± 0.5% vs. 0.8 ± 0.4 before treatment), after which the CTLA-4 levels gradually decreased. Similar dynamic changes were seen in the levels of IFN-γ and IL-10. The dynamic changes of CD28 and CTLA-4 were consistent with those of IFN-γ and IL-10 and with the effectiveness of HD-DXM in the treatment of ITP. Our results suggest that a disturbed CD28/CTLA-4 balance may contribute to the immunopathogenesis of ITP.

T regulatory markers expression in unexplained recurrent spontaneous abortion

OBJECTIVE

To evaluate expression of glucocorticoid-induced tumor necrosis factor receptor (GITR), cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and IL-10 in peripheral blood mononuclear cells (PBMCs) of 20 women with unexplained recurrent spontaneous abortion (URSA) compared to 20 normal non-pregnant women (NNP) during luteal phase in the window of implantation.

METHODS

Quantitative real-time PCR (qRT-PCR) was performed using the Taqman method for expression of GITR and SYBR Green method for expression of CTLA-4 and IL-10.

RESULTS

Expression of CTLA-4 in the NNPs (median; interquartile range; 3; 1.8-10) was significantly higher than the URSAs (0.72; 0.26-3.81, p = 0.015). Expression of GITR in the NNPs (53; 10-139) was significantly higher than the URSAs (6; 3-27, p = 0.005). However, IL-10 expression in the URSAs was significantly higher than the NNPs, did not meet a significant value. A significant correlation was found between CTLA-4 and GITR expression in the study population (p = 0.0001).

CONCLUSIONS

Expression of CTLA-4 and GITR were significantly down-regulated in the URSAs compared to NNPs at the window of implantation, which shows the essential role of Treg cells in creating an immunological privileged site for fetus as an allograft at the maternal-fetal interface by high expression levels of CTLA-4 and GITR during a normal pregnancy.

The Galectin-9/Tim-3 pathway is involved in the regulation of NK cell function at the maternal-fetal interface in early pregnancy

Decidual natural killer (dNK) cells actively participate in the establishment and maintenance of maternal-fetal immune tolerance and act as local guardians against infection. However, how dNK cells maintain the immune balance between tolerance and anti-infection immune responses during pregnancy remains unknown. Here, we demonstrated that the inhibitory molecule T-cell immunoglobulin domain and mucin domain-containing molecule-3 (Tim-3) are expressed on over 60% of dNK cells. Tim-3(+) dNK cells display higher interleukin (IL)-4 and lower tumor necrosis factor (TNF)-α and perforin production. Human trophoblast cells can induce the transformation of peripheral NK cells into a dNK-like phenotype via the secretion of galectin-9 (Gal-9) and the interaction between Gal-9 and Tim-3. In addition, trophoblasts inhibit lipopolysaccharide (LPS)-induced pro-inflammatory cytokine and perforin production by dNK cells, which can be attenuated by Tim-3 neutralizing antibodies. Interestingly, a decreased percentage of Tim-3-expressing dNK cells were observed in human miscarriages and murine abortion-prone models. Moreover, T helper (Th)2-type cytokines were decreased and Th1-type cytokines were increased in Tim-3(+) but not Tim-3(-) dNK cells from human and mouse miscarriages. Therefore, our results suggest that the Gal-9/Tim-3 signal is important for the regulation of dNK cell function, which is beneficial for the maintenance of a normal pregnancy.

To drive or be driven: the path of a mouse model of recurrent pregnancy loss

This review is an example of the use of an animal model to try to understand the immune biology of pregnancy. A well-known model of recurrent spontaneous pregnancy loss is put in clinical, historical, and theoretical context, with emphasis on T cell biology.

Endometrial gene expression profiling in pregnant Meishan and Yorkshire pigs on day 12 of gestation

Background

Litter size in pigs is a major factor affecting the profitability in the pig industry. The peri-implantation window in pigs is characterized by the coordinated interactions between the maternal uterine endometrium and the rapidly elongating conceptuses and represents a period of time during which a large percentage of the developing conceptuses are lost. However, the gene expression and regulatory networks in the endometrium contributing to the establishment of the maternal: placental interface remain poorly understood.

Results

We characterized the endometrial gene expression profile during the peri-implantation stage of development by comparing two breeds that demonstrate very different reproductive efficiencies. We employed the porcine Affymetrix GeneChip® to assay the transcriptomic profiles of genes expressed in the uterine endometrium obtained from Meishan and Yorkshire gilts (n = 4 for each breed) on day 12 of gestation (M12 and Y12, respectively). Total of 17,076 probesets were identified as "present" in at least two arrays. A mixed model-based statistical analysis predicted a total of 2,656 (q < 0.1) transcripts as differentially expressed between Meishan and Yorkshire pigs. Eighteen differentially expressed transcripts of interest were validated by quantitative real-time PCR. Gene ontology (GO) annotation revealed that the known functions of the differentially expressed genes were involved in a series of important biological processes relevant to early pregnancy establishment in the pig.

Conclusions

The results identified endometrial gene expression profiles of two breeds differing in litter size and identified candidate genes that are related to known physiological pathways related to reproductive prolificacy. These findings provide a deeper understanding of molecular pathways differing between two breeds at the critical peri-implantation stage of pregnancy, which can be utilized to better understand the events contributing to pregnancy establishment in the pig.

Self-specific memory regulatory T cells protect embryos at implantation in mice

Regulatory T cells (Tregs) play crucial roles in both fetal and tumor development. We recently showed that immunosurveillance by pre-existing CD44(high)CD62L(low) activated/memory Tregs (amTregs) specific for self-Ags protects emergent tumor cells in mice. This Treg response of a memory type is more rapid than and dominates the antitumor response of tumor-specific effector T cells. In this study, we report striking similarities between the early Treg responses to embryo and tumor implantation. Tregs are rapidly recruited to uterus-draining lymph nodes and activated in the first days after embryo implantation in both syngeneic and allogeneic matings; express the markers of the amTreg subset; and are at least in part self-Ag specific, as seen in tumor emergence. Unlike in the tumor emergence setting, however, for which preimmunization against tumor Ags is sufficient for complete tumor eradication even in the presence of Tregs, Treg depletion is additionally required for high frequencies of fetus loss after preimmunization against paternal tissue Ags. Thus, amTregs play a major role in protecting embryos in both naive and preimmune settings. This role and the ensuing therapeutic potential are further highlighted by showing that Treg stimulation, directly by low-dose IL-2 or indirectly by Fms-related tyrosine kinase 3 ligand, led to normal pregnancy rates in a spontaneous abortion-prone model.

Adenovirus mediated CTLA4Ig transgene therapy alleviates abortion by inhibiting spleen lymphocyte proliferation and regulating apoptosis in the feto-placental unit

Pregnancy is thought to be a state of immunological tolerance. The mechanisms underlying this phenomenon are still poorly understood. In our previous study, adenovirus mediated CTLA4Ig transgene (Ad-CTLA4Ig) therapy was demonstrated to improve pregnancy outcome in an abortion-prone mouse model by skewing the Th2/Th1 cytokine balance, expanding peripheral CD4(+) CD25(+) regulatory T cell populations and inducing indoleamine 2,3 dioxygenase (IDO) mRNA expression at the maternal-fetal interface. However, it is still not clear whether other mechanisms are involved in the protective effect of CTLA-4 on pregnancy outcome in abortion-prone matings. In this study, we focused on the effect of CTLA4Ig on spleen lymphocyte proliferation and apoptosis at the maternal-fetal interface. We demonstrated that Ad-CTLA4Ig therapy inhibited the proliferation of CBA/J splenocytes and IL-2 secretion in response to DBA/2 stimulator cells in the abortion-prone mice model. Ad-CTLA4Ig therapy also skewed cytokine production toward a Th2 bias and regulated the expression of anti-apoptosis factor Bcl-2 and pro-apoptosis factor Bax at the maternal-fetal interface. However, it did not influence the apoptosis and cell cycles of splenocytes in pregnant CBA/J mice. On the whole, these findings indicated that Ad-CTLA4Ig therapy could ameliorate the outcome of spontaneous abortion by inhibiting proliferation of maternal spleen lymphocytes and regulating apoptosis in the feto-placental unit.

Cyclosporine A enhances Th2 bias at the maternal-fetal interface in early human pregnancy with aid of the interaction between maternal and fetal cells

Our previous study has demonstrated that cyclosporine A (CsA) administration in vivo induces Th2 bias at the maternal-fetal interface, leading to improved murine pregnancy outcomes. Here, we investigated how CsA treatment in vitro induced Th2 bias at the human maternal-fetal interface in early pregnancy. The cell co-culture in vitro in different combination of component cells at the maternal-fetal interface was established to investigate the regulation of CsA on cytokine production from the interaction of these cells. It was found that interferon (IFN)-γ was produced only by decidual immune cells (DICs), and not by trophoblasts or decidual stromal cells (DSCs); all these cells secreted interleukin (IL)-4, IL-10, and tumor necrosis factor (TNF)-α. Treatment with CsA completely blocked IFN-γ production in DICs and inhibited TNF-α production in all examined cells. CsA increased IL-10 and IL-4 production in trophoblasts co-cultured with DSCs and DICs although CsA treatment did not affect IL-10 or IL-4 production in any of the cells when cultured alone. These results suggest that CsA promotes Th2 bias at the maternal-fetal interface by increasing Th2-type cytokine production in trophoblasts with the aid of DSCs and DICs, while inhibiting Th1-type cytokine production in DICs and TNF-α production in all investigated cells. Our study might be useful in clinical therapeutics for spontaneous pregnancy wastage and other pregnancy complications.

[Immunological aspect of pregnancy]

Pregnancy is a temporary semi-allograft that survives for nine months. The importance of this event for the survival of the species justifies several tolerance mechanisms that are put into place at the beginning of pregnancy, some of which occur even at the time of implantation. The presence of multiple tolerance mechanisms and the richness of the means employed underline the central importance of the trophoblast. Understanding these mechanisms, and in particular, their integration into an overall scheme, enables the anomalies encountered in certain pathologies of pregnancy to be placed into context. Understanding these mechanisms and their interruption at the end of pregnancy should improve our understanding of disappointing results from current immunological treatments facilitate the implementation of new prophylactic and therapeutic strategies.

Administration of cyclosporin A to recipients improves the potential of mouse somatic cell nuclear-transferred oocytes to develop to fetuses

Somatic cell nuclear-transferred (SCNT) oocytes have a high potential for development in vitro, but a large proportion of embryos that are transferred to recipients is aborted before parturition. The precise mechanism for the high abortion rate is unknown, but abnormal placenta formation is frequently observed in SCNT-cloned pregnancies. The present study examined the effects of treating the recipients with cyclosporin A (CsA), an immunoprotectant, on the proportion of fetuses resulting from SCNT-cloned pregnancies. Cloned embryos developed from enucleated oocytes and receiving cumulus cells from F1 (C57BL/6 × DBA, H-2b/d) females were transferred to outbred ICR (in which the H-2 complex was not fixed) recipient females. Each recipient received an intraperitoneal injection of CsA or vehicle. Compared with vehicle, administration of CsA to recipients on day 4.5 of pregnancy significantly increased the proportion of fetuses observed on day 10.5. The proportion of fetuses at day 18.5 of pregnancy in recipients receiving CsA treatment was slightly higher than that in controls. This study is the first to report that CsA administration increases the proportion of fetuses resulting from SCNT-cloned pregnancies.

Regulation of costimulatory signal in maternal-fetal immune tolerance

A pregnancy is associated with modifications in the immune status of the mother, but the mechanisms are not well understood. Several observations have indicated that CD28/CTLA-4 and B7-1/B7-2 are involved in the maternal-fetal immune regulation. This review aims to recapitulate our current knowledge concerning the role of CD28/CTLA-4 and B7-1/B7-2 in maternal-fetal immune regulation. Several studies suggest that up-regulation of B7-2 and/or CD28 and/or down-regulation of CTLA-4 are correlated with the occurrence of pregnancy loss. Therefore, an accurate expression of costimulatory molecules at the maternal-fetal interface may ensure that the decidual cells do not elicit a 'danger' signal to the maternal immune system, perhaps instead contributing to the establishment of immune tolerance in vivo. It is showed that costimulation blockade with anti-B7 mAbs results in altered allogeneic T-cell response and overcomes increased maternal rejection to the fetus, which improves fetus growth in the abortion-prone system. These findings suggest that the anti-B7-treated T cells not only function as potent suppresser cells but also exert immunoregulatory effect on the maternal T cells. This procedure might be potentially useful to immunotherapy for human recurrent spontaneous abortion.

CTLA4Ig gene transfer alleviates abortion in mice by expanding CD4+CD25+ regulatory T cells and inducing indoleamine 2,3-dioxygenase

Successful pregnancy requires a state of immunological tolerance since normally the maternal immune system does not reject the semi-allogeneic conceptus. Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), a ligand for B7, delivers negative signals to antigen presenting cells (APCs) to compete with CD28 for binding to B7 molecules and down-regulate proinflammatory responses, thus inhibiting T cell activation. Using CBA/J x DBA/2 matings as an abortion-prone model, we observed that adenovirus-mediated CTLA4Ig (Ad-CTLA4Ig) gene transfer improves pregnancy outcome. Ad-CTLA4Ig therapy skewed the ability of serum cytokine production toward a Th2 bias. Flow cytometry revealed that Ad-CTLA4Ig administration expanded peripheral CD4(+)CD25(+) regulatory T cell populations in CBA/J x DBA/2 matings. Furthermore, Ad-CTLA4Ig administration induced indoleamine 2,3-dioxygenase (IDO) and Foxp3 mRNA expression at the materno-fetal interface. Our results demonstrate that adenovirus-mediated CTLA4Ig gene transfer improves pregnancy outcome in a murine model of abortion by expanding the CD4(+)CD25(+) regulatory T cell population and inducing IDO mRNA expression.