The role of the indoleamine 2,3-dioxygenase gene in preventing ovarian transplant rejection in rats†.

Indoleamine 2,3-dioxygenase (IDO) plays important roles in maternal immune tolerance. Female Sprague Dawley rats (9-11 weeks old) were randomly divided into an autoplastic transplantation group (n = 75) and an allograft transplantation group (n = 300) was further divided into subgroups of ovarian transplantation, allograft ovarian transplantation, allograft ovarian transplantation with cyclosporine A treatment, allograft ovarian transplantation and transfection with IDO-expressing lentiviruses, and allograft ovarian transplantation and transfection with control lentiviruses. IDO was successfully transfected into the transplanted ovarian tissue. The survival rate, success rate of ovarian transplantation, period until estrous cycle restoration, and estrogen levels of rats that received IDO-expressing lentiviruses were significantly different from those of rats that underwent allograft transplantation and with control transfection (all P < 0.05), but not significantly different from those rats that received autoplastic transplantation (all P > 0.05). The number of ovarian follicles in the transplanted ovarian tissue of rats that received IDO-expressing lentiviruses was also significantly higher. The expression level of IDO protein detected by immunohistochemistry and western blotting was especially high in ovaries that had received IDO-containing lentiviruses. Naturally pregnant rats were found in each group postoperatively. These results indicated that IDO-expressing lentiviruses were successfully transfected into transplanted ovarian tissues of rats and that IDO was stably expressed within a certain time. These findings suggest that the expression level of IDO protein is associated with an enhanced success rate of ovarian tissue transplantation and a short restoration period of endocrine function.

Impact of having surplus blastocysts cryopreserved on the ongoing pregnancy rate following a fresh transfer.

PURPOSE: This study aimed to investigate whether a surplus of vitrified blastocysts correlated with ongoing pregnancy by analyzing the clinical outcomes of fresh transfer cycles with/without a surplus of vitrified blastocysts. METHODS: This was a retrospective analysis carried out in the Reproductive Medicine Center of Guizhou Medical University Affiliated Hospital between January 2020 and December 2021. Overall, 2482 fresh embryo transfer cycles were included in this study, including 1731 cycles with a surplus of vitrified blastocysts (group A) and 751 cycles with no surplus of vitrified blastocysts (group B). The clinical outcomes of fresh embryo transfer cycles were analyzed and compared between the two groups. RESULTS: In total, the clinical pregnancy rate (CPR) and ongoing pregnancy rate (OPR) after fresh transfer in group A were significantly higher than those in group B (59% vs. 34.1%, p < .001; 51.9% vs. 27.8%, p < .001, respectively). Moreover, the miscarriage rate was significantly lower in group A when compared to that in group B (10.8% vs. 16.8%, p = .008). When grouped by either female age or the number of good-quality embryos transferred, the same trends for CPR and OPR were seen in all subgroups. After adjusting for potential confounding factors in multivariate analysis, a surplus of vitrified blastocysts remained significantly associated with a higher OPR (OR: 1.52; 95% CI:1.21-1.92). CONCLUSION: Ongoing pregnancy outcome increases significantly in fresh transfer cycle with a surplus of vitrified blastocysts.

Molecular mechanisms involved in the IL-6-mediated upregulation of indoleamine 2,3-dioxygenase 1 (IDO1) expression in the chorionic villi and decidua of women in early pregnancy.

BACKGROUND: IL-6 induces the upregulation of indoleamine 2,3-dioxygenase (IDO1) at the maternal-foetal interface, but the regulation mechanisms of IDO1 by IL-6 at this interface have not been fully understood. METHODS: Western blotting, qRT-PCR and/or immunohistochemistry were employed to measure the expression of IDO1, IL-6, SHP-1/2, SOCS3 and STAT3/p (STAT3 and pSTAT3) in tissues of chorionic villi and decidua (TCVD) in vivo and in cultured TCVD that were treated with IL-6 in the presence or absence of an IL-6 inhibitor. RESULTS: Mutually positive relationships among the protein levels of IL-6, IDO1, SHP-1/2 and STAT3/p was observed, and the expression of IDO1, SHP-1/2 and STAT3/p was increased in a dose-dependent manner in TCVD in vivo and in cultured TCVD treated with IL-6 at increasing concentrations (0-100 ng/ml). The level of IL-6 was negatively related to SOCS3 level in TCVD. The expression of SOCS3 was increased in a dose-dependent manner, and SOCS3 level was positively correlated with SHP-1, SHP-2 and STAT3/p level in cultured TCVD treated with 0-2 ng/ml IL-6; however, opposite results were observed after treatment with 2-100 ng/ml IL-6. The IL-6-induced upregulation of IDO1, SHP-1, SHP-2 and STAT3/p expression could be reversed, while the IL-6-induced upregulation of SOCS3 expression was exacerbated by Corylifol A. CONCLUSIONS: In normal pregnancy, IL-6 upregulates the expression of IDO1 by promoting SHP-1/2 expression via STAT3/p and simultaneously negatively regulates the expression of SOCS3. High expression of IL-6 causes the upregulation of IDO1 expression and the downregulation of SOCS-3 expression, which may be beneficial for maintaining immunological tolerance.

Non-NF2 mutations have a key effect on inhibitory immune checkpoints and tumor pathogenesis in skull base meningiomas.

AIMS: Skull base meningiomas represent approximately 25% of all meningiomas, nearly 20% of which are atypical or anaplastic. To date, effective medical treatments for meningiomas are still lacking. Genetic aberrations (TRAF7, KLF4, AKT1, and SMO) and the effects of genetic aberrations on the expression of inhibitory immune checkpoint molecules (PD-L1, IDO, and TDO2) in skull base meningiomas are still unclear. METHODS: Genetic alterations in the four genes were identified in 92 skull base meningiomas by Sanger sequencing. The expression differences in immune checkpoints between mutant and wild-type (WT) tumors were determined by immunohistochemistry (IHC) and Western blot (WB). RESULTS: The four mutations were not concurrently detected in the patients with skull base meningiomas. Among the tumors from the KLF4-mutated group, almost half were petroclival meningiomas. KLF4- and TRAF7-mutated tumors were predominantly secretory meningiomas. SMO-mutated tumors exhibited higher calcification, and half of these tumors were observed in the brain midline. Receiver operating characteristic curve analysis indicated that tumor volume can predict KLF4 and TRAF7 mutation status with high sensitivity and specificity, respectively. The IHC and WB analyses indicated that PD-L1, IDO, and TDO2 levels in tumors with TRAF7 mutations were significantly higher than those in WT tumors. Meanwhile, there was a significant difference in TDO2 between tumors with AKT1 mutations and WT tumors. Specifically, TRAF7 mutations could play a key role in skull base meningiomas by regulating the expression of inhibitory immune checkpoints and thus suppressing immune responses. CONCLUSIONS: Checkpoint inhibitors may be potential strategies for targeted immunotherapies of these mutant meningiomas.

miR-100 promotes the proliferation of spermatogonial stem cells via regulating Stat3.

Micro RNAs play important roles during mammalian spermatogenesis, but the function(s) of specific miRNAs remain largely unknown. Here, we report that miR-100 is predominantly expressed in undifferentiated murine spermatogonia, including spermatogonial stem cells (SSCs). We utilized a miRNA mimic and inhibitor to knock down and overexpress miR-100 in cultured SSCs, respectively, finding that the miR-100 promotes the proliferation of SSCs in vitro. Furthermore, signals promoting SSC maintenance induced, whereas retinoic acid repressed, expression of miR-100. Stat3 expression was modulated by miR-100, with increased transcript and protein abundance in the presence of the miR-100 inhibitor versus reduced protein levels following miR-100 overexpression. Stat3 silencing also mimicked the reduced SSC proliferation phenotype associated with elevated miR-100 levels. Importantly, Stat3 silencing rescued the anti-proliferation capacity of miR-100 inhibitor on cultured SSCs. Given that the Stat3 3' untranslated region was not repressed by pre-miR-100 in a standard luciferase reporter assay, we suggest that miR-100 promotes SSC proliferation by indirect regulation of Stat3.

Enhanced antitumor effects of adenoviral-mediated siRNA against GRP78 gene on adenosine-induced apoptosis in human hepatoma HepG2 cells.

Our previous studies show that adenosine-induced apoptosis is involved in endoplasmic reticulum stress in HepG2 cells. In this study, we have investigated whether knockdown of GRP78 by short hairpin RNA (shRNA) increases the cytotoxic effects of adenosine in HepG2 cells. The adenovirus vector-delivered shRNA targeting GRP78 (Ad-shGRP78) was constructed and transfected into HepG2 cells. RT-PCR assay was used to determine RNA interference efficiency. Effects of knockdown of GRP78 on adenosine-induced cell viabilities, cell-cycle distribution and apoptosis, as well as relative protein expressions were determined by flow cytometry and/or Western blot analysis. The intracellular Ca2+ concentration was detected by laser scanning confocal microscope. Mitochondrial membrane potential (ΔΨm) was measured by a fluorospectrophotometer. The results revealed that GRP78 mRNA was significantly downregulated by Ad-shGRP78 transfection. Knockdown of GRP78 enhanced HepG2 cell sensitivity to adenosine by modulating G0/G1 arrest and stimulating Bax, Bak, m-calpain, caspase-4 and CHOP protein levels. Knockdown of GRP78 worsened cytosolic Ca2+ overload and ΔΨm loss. Knockdown of caspase-4 by shRNA decreased caspase-3 mRNA expression and cell apoptosis. These findings indicate that GRP 78 plays a protective role in ER stress-induced apoptosis and show that the combination of chemotherapy drug and RNA interference adenoviruses provides a new treatment strategy against malignant tumors.

Retraction of: "Risk factors for poor ovarian response in patients receiving in-vitro fertilization and embryo transfer".

The paper entitled "Risk factors for poor ovarian response in patients receiving in-vitro fertilization and embryo transfer" by Chen et al., which was published in Minerva Surgery 2023 June;78(3):303-4, has been retracted by the Publisher upon the authors' request; they asked for a retraction because the paper contains faulty data.

Identification of a novel glioblastoma multiforme molecular subtype with poor prognosis and high immune infiltration based on oxidative stress-related genes.

Glioblastoma multiforme (GBM) is a highly malignant primary brain tumor with a poor prognosis. Reactive oxygen species that accumulate during tumorigenesis can cause oxidative stress (OS), which plays a crucial role in cancer cell survival. Clinical and transcriptome data of TCGA-GBM dataset from UCSC Xena database were analyzed. Consensus clustering analysis was conducted to identify OS-related molecular subtypes for GBM. The immune infiltrate level between subtypes were characterized by ESTIMATE algorithm. Differentially expressed genes (DEGs) between subtypes were screened by DESeq2 package. Two OS-related molecular subtypes of GBM were identified, and cluster 2 had poorer overall survival and higher immune infiltration levels than cluster 1. Enrichment analysis showed that 54 DEGs in cluster 2 were significantly enriched in cytokine/chemokine-related functions or pathways. Ten hub genes (CSF2, CSF3, CCL7, LCN2, CXCL6, MMP8, CCR8, TNFSF11, IL22RA2, and ORM1) were identified in GBM subtype 2 through protein-protein interaction network, most of which were positively correlated with immune factors and immune checkpoints. A total of 55 small molecule drugs obtained from drug gene interaction database (DGIdb) may have potential therapeutic effects in GBM subtype 2 patients. Our study identified 10 hub genes as potential therapeutic targets in GBM subtype 2 patients, who have poorer overall survival and higher immune infiltration levels. These findings could pave the way for new treatments for this aggressive form of brain cancer.

Exploring the clinical and cellular mechanisms of LncRNA-KCNQ1OT1/miR-29a-3p/SOCS3 molecular axis in cases of unexplained recurrent spontaneous abortion.

OBJECTIVE: The objective of this study is to explore the functions and mechanisms of the LncRNA-KCNQ1OT1/miR-29a-3p/SOCS3 molecular pathway in the context of unexplained recurrent spontaneous abortion (URSA). METHODS: We conducted qRT-PCR to assess the levels of LncRNA-KCNQ1OT1, miR-29a-3p, and SOCS3 in both abortion tissues from women who experienced URSA and healthy early pregnant women. A dual-luciferase assay was employed to investigate whether miR-29a-3p targets SOCS3. Furthermore, RNA IP and RNA Pull-Down assays were employed to confirm the interaction between KCNQ1OT1 and SOCS3 with miR-29a-3p. RNA FISH was used to determine the cellular localization of KCNQ1OT1. Additionally, trophoblast cells (HTR8/SVneo) were cultured and the CCK-8 assay was utilized to assess cell proliferation, while flow cytometry was employed to analyze cell apoptosis. RESULTS: Compared to abortion tissues obtained from healthy early pregnant individuals, those from women who experienced URSA displayed a notable downregulation of KCNQ1OT1 and SOCS3, accompanied by an upregulation of miR-29a-3p. Suppression of KCNQ1OT1 resulted in the inhibition of cell proliferation and the facilitation of apoptosis in HTR8/SVneo cells. Our findings suggest that KCNQ1OT1 may exert a regulatory influence on SOCS3 through a competitive binding mechanism with miR-29a-3p. Notably, KCNQ1OT1 exhibited expression in both the cytoplasm and nucleus, with a predominant localization in the cytoplasm. Furthermore, we observed a negative regulatory relationship between miR-29a-3p and SOCS3, as the miR-29a-3p mimic group demonstrated significantly reduced cell proliferation and an increased rate of apoptosis when compared to the negative control (NC mimic) group. Additionally, the SOCS3 Vector group exhibited a substantial improvement in proliferation capability and a marked reduction in the apoptosis rate in comparison to the NC Vector group. The miR-29a-3p mimic + SOCS3 Vector group demonstrated a remarkable enhancement in proliferation and a reduction in apoptosis when compared to the miR-29a-3p mimic group. CONCLUSION: The competitive binding of miR-29a-3p to LncRNA-KCNQ1OT1 appears to result in the elevation of SOCS3 expression, consequently fostering the proliferation of trophoblast cells while concomitantly suppressing apoptosis.

Proband-independent haplotyping based on NGS-based long-read sequencing for detecting pathogenic variant carrier status in preimplantation genetic testing for monogenic diseases.

Preimplantation genetic testing for monogenic diseases (PGT-M) can be used to select embryos that do not develop disease phenotypes or carry disease-causing genes for implantation into the mother's uterus, to block disease transmission to the offspring, and to increase the birth rate of healthy newborns. However, the traditional PGT-M technique has some limitations, such as its time consumption, experimental procedural complexity, and the need for a complete family or reference embryo to construct the haplotype. In this study, proband-independent haplotyping based on NGS-based long-read sequencing (Phbol-seq) was used to effectively construct haplotypes. By targeting the mutation sites of single gene disease point mutations and small fragment deletion carriers, embryos carrying parental disease-causing mutations were successfully identified by linkage analysis. The efficiency of embryo resolution was then verified by classical Sanger sequencing, and it was confirmed that the construction of haplotype and SNP linkage analysis by Phbol-seq could accurately and effectively detect whether embryos carried parental pathogenic mutations. After the embryos confirmed to be nonpathogenic by Phbol-seq-based PGT-M and confirmed to have normal copy number variation by Phbol-seq-based PGT-A were transplanted into the uterus, gene detection in amniotic fluid of the implanted embryos was performed, and the results confirmed that Phbol-seq technology could accurately distinguish normal genotype embryos from genetically modified carrier embryos. Our results suggest that Phbol-seq is an effective strategy for accurately locating mutation sites and accurately distinguishing between embryos that inherit disease-causing genes and normal embryos that do not. This is critical for Phbol-seq-based PGT-M and could help more single-gene disease carriers with incomplete families, de novo mutations or suspected germline mosaicism to have healthy babies with normal phenotypes. It also helps to reduce the transmission of monogenic genetic diseases in the population.

Overexpression of CD2/CD27 could inhibit the activation of nitrogen metabolism pathways and suppress M2 polarization of macrophages, thereby preventing brain metastasis of breast cancer.

OBJECTIVE: Our study aimed to reveal the possible molecular mechanisms of CD2 and CD27 in influencing the tumor microenvironment of breast cancer (BC) brain metastasis based on the TCGA (The Cancer Genome Atlas) and SRA (Sequence Read Archive) databases. METHODS: We calculated the proportions of tumor-infiltrating immune cells and the immune and stromal cell scores in 1222 BC samples from the TCGA-BRCA dataset, followed by identification of candidate DEGs. We further screened for BC brain metastasis-related DEGs in the BC brain metastasis dataset SUB12911144 from the SRA database. Finally, we established a mouse breast cancer brain metastasis model for in vivo validation. RESULTS: We further screened two immune-regulatory DEGs (CD2 and CD27). GSEA analysis showed that the downregulation of CD2 and CD27 expression was closely related to the activation of nitrogen metabolism pathways. CIBERSORT algorithm analysis showed a correlation between the expression of 16 types of tumor-infiltrating immune cells and CD2 and 19 types of tumor-infiltrating immune cells and CD27. In addition, CD2 and CD27 expression were negatively associated with the proportion of M2 macrophages. In vivo experimental results demonstrated that overexpression of CD2/CD27 could suppress the M2 polarization of macrophages and inhibit breast cancer brain metastasis. CONCLUSION: In the tumor microenvironment, overexpression of CD2/CD27 inhibited the activation of nitrogen metabolism pathways and suppressed M2 polarization of macrophages, thereby preventing brain metastasis of breast cancer.

Methyl-CpG Binding Protein 2 as a Potential Diagnostic and Prognostic Marker Facilitates Glioma Progression Through Activation of Wnt/ß-Catenin Pathway.

BACKGROUND: Glioma is the primary malignant tumor in the central nervous system and has high malignancy, mortality, and recurrence rates. Because of its heterogeneity and drug resistance, the blood-brain barrier, and other factors, the treatment of glioma has mainly been surgical resection combined with traditional radiotherapy and chemotherapy. However, the therapeutic effect has not been satisfactory. Methyl-CpG binding protein 2 (MeCP2) is an epigenetic regulator that has been reported to regulate the initiation and progression of glioma. However, the underlying mechanism in glioma has remained unclear. METHODS: The gene expression of MeCp2, miR-138-5p, the epithelial-mesenchymal transition, the apoptosis-related gene, and the Wnt/ß-Catenin pathway-related gene and proliferation were detected by reverse transcription-quantitative polymerase chain reaction or Western blot. The cell proliferation and apoptosis of the glioma cell was assessed using the CCK-8 assay and flow cytometry assay. The relationship between miR-138-5p and MeCp2 was measured using the dual luciferase reporter assay. The effect of MeCp2 in U87 cells was examined in a xenograft tumorigenesis model in vivo. RESULTS: In our study, we found that MeCP2 was upregulated in glioma tissues and cell lines and that MeCP2 knockdown repressed cell proliferation and epithelial-mesenchymal transition but boosted cell apoptosis in glioma. Furthermore, MeCP2 knockdown attenuated in vivo glioma growth in a mice model. Mechanistically, miR-138-5p hindered the expression of MeCP2 by target MeCP2 and then inactivated the Wnt/ß-catenin signaling pathway. In addition, subsequent rescue assays disclosed that miR-138-5p repressed the glioma malignant phenotype and MeCP2 overexpression reversed the inhibitory effect of miR-138-5p upregulation. Consistently, overexpression of MeCP2 elevated glioma development. However, inhibition of the Wnt/ß-catenin signaling pathway with XAV-939 rescued the facilitation effect by overexpressing miR-138-5p. CONCLUSIONS: Our results have revealed that miR-138-5p/MeCP2/Wnt/ß-catenin signaling might be a new target axis for glioma treatment strategies.

Indoleamine 2,3-dioxygenase (IDO) downregulates the cell surface expression of the CD4 molecule.

Indoleamine 2,3-dioxygenase (IDO) has been implicated in preventing the fetus from undergoing maternal T cell-mediated immune responses, yet the mechanism underlying these kinds of IDO-mediated immune responses has not been fully elucidated. Since the CD4 molecule plays a central role in the onset and regulation of antigen-specific immune responses, and T cell is sensitive in the absence of tryptophan, we hypothesize that IDO may reduce cell surface CD4 expression. To test this hypothesis, an adenoviral vector-based construct IDO-EGFP was generated and the effect of IDO-EGFP on CD4 expression was determined on recombinant adenoviral infected C8166 and MT-2 cells, by flow cytometry and/or Western blot analysis. The results revealed a significant downregulation of cell membrane CD4 in pAd-IDOEGFP infected cells when compared to that of mock-infected cells or infection with empty vector pAd-EGFP. Further experiments disclosed that either an addition of tryptophan or IDO inhibitor could partly restore CD4 expression in pAd-IDOEGFP infected C8166 cells. Our findings suggest that downregulation of CD4 by IDO might be one of the mechanisms through which IDO regulates T cell-mediated immune responses.

[Microsurgical treatment for jugular foramen meningiomas].

OBJECTIVE: To explore the microsurgical treatment and clinical efficacies of jugular foramen meningiomas. METHODS: A total of 28 patients with jugular foramen meningiomas undergoing microsurgical operations at Beijing Tiantan Hospital during the period from April 1996 to April 2011 were analyzed retrospectively. The retrosigmoid suboccipital (n = 13), far lateral (n = 9), postauricular trans-supracondylar (n = 4) and trans-paracondylar approaches (n = 2) were used. RESULTS: Complete tumor resection was achieved in 18 patients and subtotal tumor resection in 10 patients. Twenty-two patients were followed up for a mean follow-up period of 3 years. The postoperative Karnofsky performance scale was above 80 in 19 patients. Twelve patients experienced hoarseness or bucking, 11 lived independently and 2 died of tumor recurrence. CONCLUSION: Jugular foramen meningiomas have a higher recurrence rate and severe cranial nerve damages may occur postoperatively. It is important to classify them into different clinical entities and choose appropriate surgical approaches and techniques so as to achieve satisfactory outcomes.

[IL-6 up-regulates indoleamine 2, 3-dioxygenase (IDO) expression in chorionic villi and decidua].

Objective To investigate the regulatory effect of interleukin-6 (IL-6) on the expression of indoleamine 2, 3-dioxygenase (IDO) in the early pregnant chorionic villi and decidua tissues. Methods The chorionic villi and decidua tissues of women who received induced abortion at early pregnancy were collected. The expression of IL-6 and IDO in the chorionic villi and decidua tissues was detected by Western blotting. Subsequently, 10, 50 and 100 ng/mL IL-6 was added into the chorionic villi and decidua tissues to culture for 48 hours. In addition, changes in the IDO mRNA and protein expression levels in chorionic villi and decidua tissues were detected by real-time quantitative reverse PCR (qRT-PCR) and Western blotting. Results Both IDO and IL-6 were expressed in human early pregnant chorionic villi and decidua tissues. Besides, the expression of these two proteins were positively correlated (r=0.72, 0.91). After being cultured with 10, 50 and 100 ng/mL IL-6 for 48 hours, IDO protein expression significantly increased in the cultured early pregnant chorionic villi and decidua tissues in an IL-6 concentration-dependent manner. Conclusion The expression of IL-6 and IDO proteins at the maternal-fetal interface show a positive correlation in normal physiological pregnancy, and IL-6 may up-regulate the expression of IDO.

Progesterone decreased indoleamine 2,3-dioxygenase 1(IDO1) expression in early pregnancy chorionic villi and decidua.

Indoleamine 2,3-dioxygenase1(IDO1) is one of the most important proteins in protect the embryos from the mother's immune system during pregnancy. However, the regulation of the protein expression at the maternal-foetal interface is not fully known. We aimed to study the regulation of IDO1 expression by progesterone in villi and decidua of in early pregnancy. Fifty cases of early pregnancy women's villi and decidua were collected. Tissue explants of chorionic villi and the decidua were cultured in media containing in different concentrations of progesterone, in the presence or absence of mifepristone. Western blot analysis and immunofluorescence were used to detect the expression of IDO1 in chorionic villi and decidua in cultured tissues. IDO1 protein was identified in chorionic villi and decidua tissues of normal pregnant women, and the expression of IDO1in the decidua was significantly higher than those in chorionic villi. Progesterone decreased IDO1 expression in early pregnancy chorionic villi and decidua, and mifepristone, as the progesterone inhibitor, reverted this effect. In normal physiological state of pregnancy, progesterone may be involved in the regulation of immune tolerance by negative regulation of IDO1 expression at maternal foetal interface. Progesterone may down-regulate IDO1 expression during early pregnancy.

Effect of the IDO Gene on Pregnancy in Mice with Recurrent Pregnancy Loss.

The aim of this study is to investigate the effect of the IDO (indoleamine 2,3-dioxygenase) gene on pregnancy outcome in mice with recurrent pregnancy loss (RPL) and its mechanism of action in the maternal-fetal interface. An RPL model was established via natural mating of female CBA/J mice with male DBA/2 mice; thereafter, the female mice were randomly divided into groups treated with LV-EGFP (enhanced green fluorescent protein)-IDO (lentivirus vector carrying IDO-EGFP gene), LV-EGFP (negative control lentivirus vector), or phosphate-buffered saline (control). The mice were sacrificed at 13.5 days of pregnancy, and the embryo absorption rate was determined. Peripheral blood regulatory T cells (Tregs) from the pregnant mice were detected using flow cytometry. Placental and decidual tissue IDO expression was detected using immunofluorescence and Western blotting. Inflammatory cell infiltration of the placental and decidual tissue was observed using hematoxylin-eosin (HE) staining. The LV-EGFP-IDO group had a significantly lower embryo absorption rate than the LV-EGFP and control groups (P = 0.0006 and P = 0.0049, respectively) and significantly more Tregs than the LV-EGFP and control groups (P = 0.0151 and P = 0.0392, respectively). Placental and decidual IDO protein levels correlated positively with peripheral blood Treg expression levels. The LV-EGFP-IDO group had significantly higher placental and decidual IDO protein levels than the LV-EGFP and control groups (P < 0.005), and it had significantly less inflammatory cell infiltration than the LV-EGFP and control groups. The IDO gene may reduce the embryo absorption rate in an RPL mouse model, possibly improving pregnancy outcome by upregulating Tregs and reducing the inflammatory response.

Estrogen induces IDO expression via TGF­ß in chorionic villi and decidua during early stages of pregnancy.

Indoleamine 2,3­dioxygenase (IDO) is one of the most important proteins protecting the embryos from the mother's immune system during pregnancy; however, little is known about the regulation of expression of this protein at the maternal­fetal interface. In the current study, chorionic villi and decidua were collected from women at early stages of pregnancy. Samples of chorionic villi and decidua were cultured in medium containing different concentrations of 17ß­estradiol and estriol respectively, with or without fulvestrant. Western blot analysis and/or immunofluorescent staining were used to detect the expression of transforming growth factor ß (TGF­ß) and IDO in chorionic villi and decidua tissues. Both TGF­ß and IDO were expressed in chorionic villi and decidua. The expression levels of these two proteins increased the most in samples of chorionic villi and decidua cultured in medium containing 17ß­estradiol at the concentration of 10 ng/ml, or estriol at the concentration of 1 µg/ml. This increase could be reversed when fulvestrant was added in the medium at the concentration of 10 µg/ml. IDO expression increased in a dose­dependent manner in tissue samples cultured in medium containing TGF­ß. The results of the current study revealed that administration of estrogen at doses similar to those observed in healthy pregnant women may upregulate the expression of IDO by TGF­ß, suggesting that estrogen may prevent allogeneic fetal rejection and may be used as an immunomodulator.

Estrogen induces indoleamine 2,3-dioxygenase expression via suppressors of cytokine signaling 3 in the chorionic villi and decidua of women in early pregnancy.

PROBLEM: Indoleamine 2,3-dioxygenase (IDO) is a key protein that participates in the protection of embryos against the mother's immune system during pregnancy. How the expression of this protein is regulated at the maternal-fetal interface remains largely unknown. METHOD OF STUDY: The chorionic villi and decidua of women in early pregnancy were collected. Tissue explants of the chorionic villi and decidua were cultured in media containing varying concentrations of 17ß-estradiol and estriol with or without fulvestrant. Western blot analysis and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were used to detect the expression of IDO and the suppressors of cytokine signaling 3 (SOCS3) in the cultured tissues from chorionic villi and decidua. RESULTS: Both IDO and SOCS3 were expressed in chorionic villi and decidua. The expression of IDO was increased in tissue explants from chorionic villi and decidua cultured in medium containing different concentrations of 17ß-estradiol or estriol, and this increase was reversed when fulvestrant was added to the medium. The expression of IDO was upregulated, and SOCS3 expression was downregulated the most in tissue explants from chorionic villi and decidua that were cultured in medium containing 17ß-estradiol at a concentration of 10 ng/mL or estriol at a concentration of 1 µg/mL. This increase in IDO and decrease in SOCS3 were reversed when fulvestrant was added to the medium at a concentration of 10 µg/mL. CONCLUSION: At a concentration similar to that present during pregnancy, estrogen may upregulate the expression of IDO via downregulating SOCS3, which implies that estrogen may contribute to the prevention of allogeneic fetal rejection, and further studies may strengthen the possibility of using estrogen as an immune modulator.