The progesterone derivative dydrogesterone abrogates murine stress-triggered abortion by inducing a Th2 biased local immune response

Stress is known to induce abortions in mice and humans, putatively via increased levels of abortogenic Th1 cytokines and a decrease of progesterone. Adequate levels of progesterone exert an antiabortive response through binding to the progesterone-receptor, which induces the release of progesterone-induced blocking factor (PIBF) from lymphocytes. PIBF is highly pregnancy-protective by induction of a Th2 biased immune activity. The aim of this study was to investigate the effect of the progesterone derivative dydrogesterone (6-dehydro-retroprogesterone) in stress-triggered murine abortion. DBA/2J-mated CBA/J female mice were randomized in different groups: two groups were treated with different dydrogesterone dosages in a single injection before exposure to sound stress on Day 5 of pregnancy, one group was exposed to stress without dydrogesterone treatment, the fourth group received no stress and no dydrogesterone. On gestation Day 13, a highly elevated abortion rate was detected in stressed mice compared to control mice. Stressed animals presented lower levels of progesterone and PIBF in plasma and a reduced staining intensity of progesterone receptor at the feto-maternal interface. Injection of dydrogesterone abrogated the effect of stress on the abortion rate. Further, dydrogesterone increased levels of plasma PIBF in stressed mice, but did not affect progesterone levels. Interestingly, dydrogesterone dramatically increased the percentage of IL-4 positive decidual immune cells in stressed mice. Our data suggest that dydrogesterone abrogates stress-triggered abortion by inducing a Th2 biased local immune response.     

Selectin, platelet plays a critical role in granulocyte access to the pregnant mouse uterus under physiological and pathological conditions

Leukocyte recruitment to the pregnant mouse uterus is associated with highly regulated patterns of expression of vascular adhesion receptors. One striking observation is the localized expression of mucosal vascular addressin cell adhesion molecule (MADCAM1) and selectin, platelet (SELP, formerly P-selectin) by maternal vessels in the vascular zone (VZ) during the first half of pregnancy. From midgestation onwards, endothelial cells lining the maternal vessels of the VZ in addition express vascular cell adhesion molecule-1 (VCAM1). The predominant cell population within these vessels is monocyte-like cells. Granulocytes and low numbers of lymphocytes are also present. Murine fetal trophoblast cells are almost devoid of adhesion molecules, including SELP. In contrast, spontaneous abortions of allogeneic pregnancies are characterized by dramatic upregulation of SELP on maternal VZ vessels and on fetal trophoblast cells. Upregulation of SELP is associated with a dramatic influx of highly activated granulocytes, which infiltrate the vessels and tissue of the VZ and the trophoblast. The majority of the activated granulocytes within the trophoblast undergo nuclear fragmentation, which can be detected by TUNEL staining. To demonstrate that SELP is involved in the recruitment of granulocytes to the pregnant uterus, we undertook long-term in vivo inhibition studies using a monoclonal antibody to inhibit the contribution of SELP to leukocyte trafficking to the decidua. In addition, the pregnant uteri of syngeneic Selp(-/-) x Selp(-/-) mice were investigated and compared to the controls. Our results clearly demonstrate the importance of SELP for granulocyte access to the pregnant mouse uterus under physiological and pathological conditions.     

Depletion of CD8+ cells abolishes the pregnancy protective effect of progesterone substitution with dydrogesterone in mice by altering the Th1/Th2 cytokine profile

One of the most remarkable immunological regulations is the maternal immune tolerance toward the fetal semiallograft during pregnancy, which has been referred to as immunity's pregnant pause. Rejection of the semiallogeneic trophoblast cells must be selectively inhibited and pathways presumably include Th2 cytokines unopposed by Th1 cytokines. Steroid hormones, including progesterone, have similar effects. Low levels of progesterone and Th2 cytokines and high levels of Th1 cytokines are attributable for increased abortions in mammalians, which may be triggered by psychoemotional stress. Thus, the aim of the present study was to provide experimental evidence for the mechanism involved in the mediation of immune responses by endocrine signals during pregnancy and stress-triggered pregnancy failure. DBA/2J-mated CBA/J female mice were randomized in three groups: 1) control females, 2) mice exposed to stress on gestation day 5.5, and 3) mice exposed to stress and substituted with dydrogesterone, a progestogen with a binding profile highly selective for the progesterone receptor on gestation day 5.5. On gestation days 7.5, 9.5, and 10.5, mice of each group were sacrificed, and the frequency of CD8(+) cells and cytokine expression (IL-4, IL-12, TNF-alpha, IFN-gamma) in blood and uterus cells was evaluated by flow cytometry. Additionally, some mice were depleted of CD8 cells by injection of mAb. We observed that progesterone substitution abrogated the abortogenic effects of stress exposure by decreasing the frequency of abortogenic cytokines. This pathway was exceedingly CD8-dependent, because depletion of CD8 led to a termination of the pregnancy protective effect of progesterone substitution.     

ICAM1 and fibrinogen-γ are increased in uterine epithelial cells at the time of implantation in rats

Uterine epithelial cells transform into a receptive state to adhere to an implanting blastocyst. Part of this transformation includes the apical concentration of cell adhesion molecules at the time of implantation. This study, for the first time, investigates the expression of ICAM1 and fibrinogen‐γ (FGG) in uterine epithelial cells during normal pregnancy, pseudopregnancy and in hormone‐treated rats. An increase (P < 0.05) in ICAM1 was seen at the apical membrane of uterine epithelial cells at the time of implantation compared with day 1 of pregnancy. ICAM1 was also increased (P < 0.05) on day 6 of pseudopregnancy as well as in ovariectomized rats treated with progesterone plus oestrogen. These results show that ICAM1 up‐regulation at the time of implantation is under the control of progesterone, and is not dependent on cytokine release from the blastocyst or in semen. FGG dimerization increased (P < 0.05) on day 6 of pregnancy compared with day 1, and was not up‐regulated in day 6 pseudopregnant animals, suggesting this increase is dependent on a developing blastocyst. The presence of ICAM1 and FGG in the uterine epithelium at the time of implantation in the rat is similar to that seen in lymphocyte–endothelium adhesion, and we suggest a similar mechanism in embryo–uterine epithelium adhesion is utilized. Mol. Reprod. Dev. 78:318–327, 2011. © 2011 Wiley‐Liss, Inc.     

An evolutionary history of the selectin gene cluster in humans

Molecules involved in leukocyte trafficking have a central role in the development of inflammatory and immune responses. We performed F(ST) analysis of the selectin cluster, as well as of SELPLG, ICAM1 and VCAM1. Peaks of significantly high population genetic differentiation were restricted to two regions in SELP and one in SELPLG. Resequencing data indicated that the region covering SELP exons 11-13 displays high nucleotide diversity in Africans and Europeans (CEU), and a high level of within-species diversity compared with inter-specific divergence. Analysis of inferred haplotypes revealed a complex phylogeny with two deeply separated clades that coalesce at ~3.5 million years (MY) plus a minor clade with a TMRCA (time to the most recent common ancestor) of ~2.2 MY. A splicing assay indicated no haplotype-specific effect on SELP exon 14 inclusion. These data are consistent with a model of multiallelic balancing selection; single-nucleotide polymorphism analysis indicated that the Val640Leu variant represents a likely selection target. In populations of Asian ancestry a distinct haplotype, possibly carrying regulatory variants, has been driven to high frequency by positive selection. No deviation from neutrality was observed for the SELPLG region. Resequencing of SELP in chimpanzees revealed a haplotype phylogeny with extremely deep basal branches, suggesting either long-standing balancing selection or ancestral population structure. Thus, SELP has experienced a complex selective history, possibly as a result of local adaptation. Variants in the gene have been associated with autoimmune and cardiovascular diseases. Association studies would benefit from both taking the complex SELP haplotype structure into account and from analysis of possible regulatory variants in the gene.     

Impaired innate immune response and enhanced pathology during Citrobacter rodentium infection in mice lacking functional P‐selectin

The selectin family of adhesion molecules mediates recruitment of immune cells to sites of inflammation which is critical for host resistance against infection. To characterize the role of selectins in host defence against Citrobacter rodentium infection, wild‐type (WT) mice and mice lacking P‐selectin glycoprotein ligand‐1 (PSGL‐1), P‐, E‐ and L‐selectin were infected using a Citrobacter‐induced colitis model. Infected mice lacking PSGL‐1 or P‐selectin showed a more pronounced morbidity associated with higher bacterial load, elevated IL‐12 p70, TNF‐α, IFN‐γ, MCP‐1 and IL‐6 production, more severe inflammation and surprisingly higher leucocyte infiltration in the guts than WT control. Recruitment of neutrophils and macrophages and caecal inflammation were drastically reduced in infected P‐selectin knockout mice receiving blocking monoclonal antibodies to ICAM‐1 or LFA‐1, indicating that these adhesion molecules may compensate for the loss of selectins in leucocyte recruitment. Furthermore, the adaptive immune response in mice lacking PSGL‐1 or P‐selectin remained functional since these infected mice were capable of eradicating the bacteria and being protected upon re‐challenge with C. rodentium. These data demonstrate a definitive phenotypic impairment of innate response in mice lacking PSGL‐1 or P‐selectin, and suggest that these adhesion molecules are important in host innate immune response against Citrobacter infection.     

Murine abortion is associated with enhanced interleukin-6 levels at the feto-maternal interface

CBA/JXDBA/2J murine abortion is known to be associated with increased local and peripheral Th1-cytokines levels. The role of the pro-inflammatory interleukin-6 (IL-6) in murine abortion remains unclear. In humans, IL-6 was reported to be elevated at the onset of spontaneous abortion. The aim of our study was to evaluate the levels of IL-6 during murine pregnancy in (1) the normal murine pregnancy combination CBA/JXBALB/c and in (2) the CBA/JXDBA/2J abortion prone mating combination. We measured IL-6 serum levels by ELISA and local (placental and decidual) IL-6 levels by flow cytometry and immunohistochemistry. The expression of the IL-6 receptor gp80 was further analyzed. We additionally evaluated the number of mast cells and macrophages at the feto-maternal interface as a putative IL-6 source in reproductive tissues. IL-6 and gp80 were expressed in decidual cells as well as in different trophoblast types. Flow cytometry analysis showed increased numbers of IL-6+ cells in abortion placentas and deciduas compared to control pregnant mice. We observed an elevated number of mast cells and macrophages at the feto-maternal interface from abortion mice in comparison to control mice. Interestingly, we found very high numbers of mast cells, macrophages and IL-6+ cells in resorption tissue compared to control tissues. Flow cytometry studies confirmed that macrophages are being an important source of IL-6 at the feto-maternal interface. The mRNA IL-6 levels were also enhanced in placenta and decidua from mice with high abortion rate compared to normal pregnant mice, as analyzed by RT-PCR. Our results suggest that IL-6 produced not only by immunocompetent cells such as macrophages and mast cells, but also by trophoblasts and decidua cells, is directly involved in the pathology of abortion.     

Apoptosis in uterine epithelium and decidua in response to implantation: evidence for two different pathways

During the initial steps of implantation, the mouse uterine epithelium of the implantation chamber undergoes apoptosis in response to the interacting blastocyst. With progressing implantation, regression of the decidual cells allows a restricted and coordinated invasion of trophoblast cells into the maternal compartment. In order to investigate pathways of apoptosis in mouse uterine epithelium and decidua during early pregnancy (day 4.5–7.0 post coitum), we have investigated different proteins such as TNFalpha, TNF receptor1, Fas ligand, Fas receptor1, Bax and Bcl2 as well as caspase-9 and caspase-3 using immunohistochemistry. To detect cells undergoing apoptosis the Tunel assay was performed. Immunoreactivity for TNFalpha as well as for TNF receptor1 was observed exclusively in the epithelium of the implantation chamber and the adjacent luminal epithelium from day 4.5 post coitum onwards. In the developing decidua the Fas ligand, but not the Fas receptor, was expressed. Bax and Bcl2 revealed a complementary expression pattern with Bax in the primary and Bcl2 in the adjacent decidual zone. Strong immunolabelling for the initiator caspase-9 was restricted to the decidual compartment, whereas caspase-3 expression characterized the apoptotic uterine epithelium. Only some caspase-3 positive decidual cells were found around the embryo which correlated to the pattern of Tunel staining. Taken together, the apoptotic degeneration of the uterine epithelium seems to be mediated by TNF receptor1 followed by caspase-3, whereas the very moderate regression of the decidua did not show the investigated death receptor, but Bax and Blc2 instead and in addition caspase-9, which indicates a different regulation for epithelial versus decidual apoptosis.     

Activin,a Grape Seed-derived Proanthocyanidin Extract,Reduces Plasma Levels of Oxidative Stress and Adhesion Molecules (ICAM-1, VCAM-1 and E-selectin) in Systemic Sclerosis

This study evaluated whether a new generation antioxidant Activin derived from the grape seed proanthocyanidins, could reduce the induction of the adhesion molecules as a result of inflammatory response in the plasma of systemic sclerosis (SSc) patients. SSc patients were divided into two groups: one group was treated with Activin, a grape seed‐derived proanthocyanidins, while the other group served as control. Patients were given Activin 100 mg/day orally for one month after which the blood samples were withdrawn from both groups of the patients. Blood was also taken from normal human volunteers. Plasma was obtained in fasting state between 8 to 9 A.M. from two groups of SSc patients and controls. Soluble adhesion molecules including ICAM‐1, VCAM‐1, E‐selectin and P‐selectin as well as malonaldehyde, a marker for oxidative stress, were measured. The results of our study demonstrated up‐regulation of these soluble adhesion molecules except for P‐selectin, in the plasma of the SSc patients compared to those obtained from human volunteers. Activin significantly attenuated the increased expression of these adhesion molecules. In addition, there was a significant increase in the amount of malondialdehyde formation in the plasma of the SSc patients, which was also attenuated by Activin. The results of this study demonstrated that Activin could reduce the inflammatory response and the oxidative stress developed in SSc patients.     

Decidual lymphocytes of human spontaneous abortions induce apoptosis but not necrosis in JEG-3 extravillous trophoblast cells

The human decidua contains an unusually high proportion of lymphocytes, mainly NK and T cells, which are potentially cytotoxic to the trophoblast when they are stimulated with certain cytokines. Given the high incidence of spontaneous abortion in humans and other species, our working hypothesis is that decidual lymphocytes are involved in immunological mechanisms that attack the trophoblast and induce abortion when any gestational problem arises. To test this hypothesis, flow cytometry was used to compare decidual lymphocyte populations in first-trimester spontaneous abortions and elective terminations of first-trimester pregnancy. We found significantly higher proportions of decidual lymphocytes that expressed activation markers, and of T cells (mainly T helper cells) in spontaneous abortions than in elective terminations of pregnancy. Decidual lymphocytes from spontaneous abortion, like decidual lymphocytes from elective termination of pregnancy and peripheral blood lymphocytes, were however, unable to lyse the JEG-3 extravillous cytotrophoblast cell line in a (51)Cr-release assay. Nevertheless, decidual lymphocytes from spontaneous abortion, unlike decidual lymphocytes from elective termination of pregnancy and peripheral blood lymphocytes, induced apoptosis in JEG-3 cells as determined by DNA fragment-release assay. Hematoxylin and eosin staining showed a significantly higher proportion of apoptotic JEG-3 cells when these cells were treated with decidual lymphocytes from spontaneous abortion than when JEG-3 cells were cultured with decidual lymphocytes from elective termination of pregnancy. The ultrastructural signs of apoptosis were confirmed by electron microscopy. These data support the hypothesis that activated decidual lymphocytes participate in human spontaneous abortion by inducing apoptosis but not necrosis of the trophoblast.     

TNFα‐induced abnormal activation of TNFR/NF‐κB/FTH1 in endometrium is involved in the pathogenesis of early spontaneous abortion

Early spontaneous abortion (ESA) is one of the most common complications during pregnancy and the inflammation condition in uterine environment such as long‐term exposure to high TNFα plays an essential role in the aetiology. Ferritin heavy chain (FTH1) is considered to be closely associated with inflammation and very important in normal pregnancy, yet the underlying mechanism of how TNFα induced abortion and its relationship with FTH1 remain elusive. In this study, we found that TNFα and FTH1 were positively expressed in decidual stromal cells and increased significantly in the ESA group compared with the normal pregnancy group (NP group). Besides, TNFα expression was positively correlated with FTH1 expression. Furthermore, in vitro cell model demonstrated that high TNFα could induce the abnormal signals of TNFR/NF‐κB/FTH1 and activate apoptosis both in human endometrium stromal cells (hESCs) and in local decidual tissues. Taken together, the present findings suggest that the excessive apoptosis in response to TNFα‐induced upregulation of FTH1 may be responsible for the occurrence of ESA, and thus provide a possible therapeutic target for the treatment of ESA.     

The expression of T-cell surface antigens CTLA-4, CD26, and CD28 is modulated by inhibition of dipeptidylpeptidase IV (DPP IV,CD26) activity in murine stress-induced abortions

Inhibition of DPP IV has been shown to abrogate the stress-related increase in murine abortions and a concomitant increase in gamma-interferon. The aim of the present study was to investigate a potential impact of the DPP IV inhibitor Isoleucine Cyanopyrrolidide on the expression of surface antigens involved in T-cell responses. DBA/2-mated CBA mice were stressed on day 5.5 of pregnancy and received injections of a DPP IV inhibitor. On day 13 of gestation, the animals were sacrificed and the percentage of abortions was determined. As shown before, stress failed to boost the abortion rate in mice receiving the DPP IV inhibitor. In stressed animals, a lower surface density of CTLA-4 on decidual CD26-positive lymphocytes was observed than in non-stressed animals. Inhibition of DPP IV restored CTLA-4 surface density to normal and decreased surface expression of CD26 and CD28 on decidual lymphocytes irrespective of stress exposure. These observations suggest that a modulation of T-cell surface antigens expression due to inhibition of DPP IV activity may contribute to the potent anti-abortogenic effect observed here.     

Anti-P- and E-selectin therapy prevents abortion in the CBA/J x DBA/2J combination by blocking the migration of Th1 lymphocytes into the foetal-maternal interface

Leukocyte migration into inflamed tissues comprises dynamic interactions between immune and endothelial cells through events controlled by adhesion molecules, e.g., P- and E-selectins, which mediate Th1 cells recruitment after injury. Since miscarriage is known to be a Th1 event and selectins are expressed at the murine foetal-maternal interface, the purpose of our study was to investigate whether blocking P- and E-selectins before implantation could inhibit Th1 migration into the foetal-maternal interface and thus prevent foetal rejection. DBA/2J-mated CBA/J females were treated with monoclonal antibodies (mAbs) against P-selectin or with both, anti-P- and anti-E-selectins combined on days 2 and 4 of pregnancy. PBS-treated females served as controls. Our data revealed a significant improvement in pregnancy outcome in both treated groups compared to the control, which is due to the effectiveness of the mAb against P-selectin, since the treatment with anti-E-selectin alone could not prevent abortion. We further observed that there was diminished Th1 cytokine production by decidual immune cells in all treated groups in comparison to the controls. Our data first confirm the important role of P-selectin in mediating the extravasation of abortive cells, while opening new therapeutic opportunities.     

Selectins Mediate Small Cell Lung Cancer Systemic Metastasis

Metastasis formation is the major reason for the extremely poor prognosis in small cell lung cancer (SCLC) patients. The molecular interaction partners regulating metastasis formation in SCLC are largely unidentified, however, from other tumor entities it is known that tumor cells use the adhesion molecules of the leukocyte adhesion cascade to attach to the endothelium at the site of the future metastasis. Using the human OH-1 SCLC line as a model, we found that these cells expressed E- and P-selectin binding sites, which could be in part attributed to the selectin binding carbohydrate motif sialyl Lewis A. In addition, protein backbones known to carry these glycotopes in other cell lines including PSGL-1, CD44 and CEA could be detected in in vitro and in vivo grown OH1 SCLC cells. By intravital microscopy of murine mesenterial vasculature we could capture SCLC cells while rolling along vessel walls demonstrating that SCLC cells mimic leukocyte rolling behavior in terms of selectin and selectin ligand interaction in vivo indicating that this mechanism might indeed be important for SCLC cells to seed distant metastases. Accordingly, formation of spontaneous distant metastases was reduced by 50% when OH-1 cells were xenografted into E-/P-selectin-deficient mice compared with wild type mice (p = 0.0181). However, as metastasis formation was not completely abrogated in selectin deficient mice, we concluded that this adhesion cascade is redundant and that other molecules of this cascade mediate metastasis formation as well. Using several of these adhesion molecules as interaction partners presumably make SCLC cells so highly metastatic.     

Induction of dual-specificity phosphatase 1 (DUSP1) by pulsatile gonadotropin-releasing hormone stimulation: role for gonadotropin subunit expression in mouse pituitary LbetaT2 cells

The adherens junction (AJ) is important for maintaining uterine structural integrity, composition of the luminal environment, and initiation of implantation by virtue of its properties of cell-cell recognition, adhesion, and establishment of cell polarity and permeability barriers. In this study, we investigated the uterine changes of AJ components E-cadherin, beta-catenin, and alpha-catenin at their mRNA and protein levels, together with the cellular distribution of meprinbeta, phospho-beta-catenin, and active beta-catenin proteins, in hamsters that show only ovarian progesterone-dependent uterine receptivity and implantation. By in situ hybridization and immunofluorescence, we have demonstrated that uterine epithelial cells expressed three of these AJ proteins and their mRNAs prior to and during the initial phase of implantation. Immunofluorescence study showed no change in epithelial expression patterns of uterine AJ proteins from Days 1 to 5 of pregnancy. With advancement of the implantation process, AJ components were primarily expressed in cells of the secondary decidual zone (SDZ), but not in the primary decidual zone (PDZ). In contrast, we noted strong expression of beta-catenin and alpha-catenin proteins in the PDZ, but not in the SDZ, of mice. Taken together, these results suggest that AJ proteins contribute to uterine barrier functions by cell-cell adhesion to ensure protection of the embryo. In addition, cleavage of E-cadherin by meprinbeta might contribute to weakening uterine epithelial cell-cell contact for blastocyst implantation. We also report that the nuclear localization of active beta-catenin from Day 4 onward in hamsters implies that beta-catenin/Wnt-signal transduction is activated in the uterus during implantation and decidualization.     

妊娠组织中CD146和HGF的表达与稽留流产的相关性分析

目的:分析妊娠组织中CD146和肝细胞生长因子(Hepatocyte growth factor,HGF)的表达与稽留流产的相关性,探讨CD146、HGF在妊娠早期的潜在作用,为早期预防稽留流产的发生提供新的思路。方法:收集2019年7月至2019年12月于我院门诊行人工流产的病例,选取妊娠时间59周,年龄1835岁,近三个月未服用激素类药物,且无子宫肌瘤、子宫内膜病变、全身免疫性疾病、内分泌疾病的病例,分为稽留流产组40例;正常妊娠组50例。分析两组资料的差异性,通过免疫组化法检测两组蜕膜组织中CD146和HGF的表达情况并分析CD146和HGF的异常表达与稽留流产是否具有相关性。结果:CD146和HGF在稽留流产组和正常早孕组蜕膜组织中均有表达;稽留流产组蜕膜组织中CD146、HGF的表达均较正常妊娠组显著降低(P<0.05);CD146和HGF的表达呈正相关性(r>0,P<0.05);CD146和HGF的异常表达与稽留流产具有相关性。结论:稽留流产患者蜕膜组织中CD146和HGF的表达均下降,可能与稽留流产的发生有关,但CD146和HGF的表达下调参与稽留流产的发生机制尚不十分明确,需进一步探讨。妊娠组织中CD146和HGF的表达可能具有正相关性。CD146和HGF可能作为稽留流产在母胎界面方向研究的新的靶点,二者在妊娠过程中可能具有正相关性,尚需实验进一步验证。     

Murine T cell determination of pregnancy outcome.

At the fetomaternal interface, maternal effector cells come in intimate contact with fetal trophoblast cells which express paternal antigens. Failure of fetal trophoblast cells to activate maternal Th1 immune responses has been attributed in part to the absence of classical Class I and Class II major histocompatibilty complex (MHC) antigen expression and elaboration of factors which reduce TcR expression and shift any immune responses which may occur to Th2. Classical TcR alphabeta(+) T cells have not been found to be able to respond to trophoblasts. Recently, TcR gammadelta(+) T cells have been characterized in the low-abortion-rate pregnant C57Bl/10 mouse decidua, and the Vgamma1(+) subset may be able to respond to trophoblasts in a non-MHC-dependent manner. Trophoblast-recognizing T cells with Vgamma1 receptors are also present in the decidua of CBA/J mice pregnant by DBA/2, an abortion-prone mating combination. To test the role of the Vgamma1 subset of decidual gammadelta T cells in abortion-prone pregnancies, we altered this subset by injecting monoclonal anti-Vgamma1.1 antibody on gestation day 5.5, 1 day after implantation. This reduced detectability of a Vgammadelta subset producing TNF-alpha and reduced the abortion rate. Anti-Vgamma2, which reacts with a similar proportion of decidual gammadelta T cells as anti-Vgamma1.1, failed to prevent abortions. Vdelta6.3(+) cells are prominent at the fetomaternal interface, and anti-Vdelta6 antibody injected on day 5.5 prevented abortions. TGF-beta2(+) gammadelta cells first appear on day 8.5 of pregnancy; anti-Vgamma1.1 antibody injection on day 8.5 depleted these cells and boosted abortions; anti-Vdelta6.3 given on day 8.5 boosted abortions to the same level. These results suggest that two populations of Vgamma1.1(+)delta6.3(+) T cells may arise in the decidua: an early population that is Th1, abortogenic, and present during the time of implantation, and a Th2/3 cell subset that is present in the decidua later during pregnancy and which is pregnancy-protective.     

Osteopontin Is Expressed in the Mouse Uterus during Early Pregnancy and Promotes Mouse Blastocyst Attachment and Invasion In Vitro

Embryo implantation into the maternal uterus is a decisive step for successful mammalian pregnancy. Osteopontin (OPN) is a member of the small integrin-binding ligand N-linked glycoprotein family and participates in cell adhesion and invasion. In this study, we showed that Opn mRNA levels are up-regulated in the mouse uterus on day 4 and at the implantation sites on days 5 and 8 of pregnancy. Immunohistochemistry localized the OPN protein to the glandular epithelium on day 4 and to the decidual zone on day 8 of pregnancy. OPN mRNA and proteins are induced by in vivo and in vitro decidualization. OPN expression in the endometrial stromal cells is regulated by progesterone, a key regulator during decidualization. As a secreted protein, the protein level of OPN in the uterine cavity is enriched on day 4, and in vitro embryo culturing has indicated that OPN can facilitate blastocyst hatching and adhesion. Knockdown of OPN attenuates the adhesion and invasion of blastocysts in mouse endometrial stromal cells by suppressing the expression and enzymatic activity of matrix metalloproteinase-9 in the trophoblast. Our data indicated that OPN expression in the mouse uterus during early pregnancy is essential for blastocyst hatching and adhesion and that the knockdown of OPN in mouse endometrial stroma cells could lead to a restrained in vitro trophoblast invasion.