Granulocyte-macrophage colony-stimulating factor promotes endometrial repair after injury by regulating macrophages in mice.

Intrauterine adhesion (IUA) caused by endometrial injury is a common cause of female infertility and is challenging to treat. Macrophages play a critical role in tissue repair and cyclical endometrial regeneration. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has significant reparative and anti-fibrotic effects in various tissues. However, there is limited research on the role of GM-CSF in the repair of endometrial injury and the involvement of macrophages in GM-CSF-mediated endometrial repair. In this study, using a mouse model of endometrial scratching injury, we found that GM-CSF treatment accelerated the repair of endometrial injury and improved fertility. At the molecular level, we observed that GM-CSF can downregulate the transcript levels of tumor necrosis factor (TNF) in mouse bone marrow-derived macrophages (BMDMs) stimulated by lipopolysaccharide (LPS) and upregulate the expression of Arginase-1 (Arg-1) and mannose receptor C-type 1 (MRC1). Importantly, during the early and middle stages of injury, GM-CSF increased the proportion of M1-like, M2-like, and M1/M2 mixed macrophages, while in the late stage of injury, GM-CSF facilitated a decline in the number of M2-like macrophages. These findings suggest that GM-CSF may promote endometrial repair by recruiting macrophages and modulating the LPS-induced M1-like macrophages into a less inflammatory phenotype. These insights have the potential to contribute to the development of novel therapeutic approaches for the treatment of intrauterine adhesion and related infertility.

Trophoblast-Derived Extracellular Vesicles Promote Preeclampsia by Regulating Macrophage Polarization.

BACKGROUND: Systemic inflammation caused by dysfunctional macrophages is a crucial pathogenetic event in preeclampsia (PE). Trophoblast-derived extracellular vesicles (T-EVs) are potent immune cell signaling modulators in pregnancy. Herein, we aimed to investigate T-EVs' effect and mechanism on macrophage polarization and its role in PE pathogenesis, which remain unclear. METHODS: Flow cytometry and immunochemistry were used to determine placental macrophage phenotypes. T-EVs were immuno-isolated via placental alkaline phosphatase antibody and identified by transmission electron microscopy and nanoparticle tracking analysis. Quantitative real-time polymerase chain reaction and flow cytometry were used to examine the effects of T-EVs on macrophage polarization, and correlation analysis of T-EVs lipidomics and macrophages transcriptome were performed to explore how T-EVs modulate macrophages. Animal experiments were established to investigate the relationship among PE, T-EVs, and macrophages. RESULTS: Macrophages shift from the M2 to M1 phenotype in the preeclamptic placenta. Also, T-EVs from women with PE (PE-EVs) significantly upregulated M1 gene markers and significantly downregulated CD163 expression in macrophages compared with T-EVs in women with normal pregnancies (NP-EVs). Mechanistically, correlation analysis with T-EVs lipidome and the transcriptome of macrophages treated with PE-EVs or NP-EVs indicated that 37 lipids altered in PE-EVs considerably affected classical inflammatory biological pathways in macrophages. Finally, animal experiments revealed that PE-EVs triggered PE-like symptoms in pregnant mice, which were alleviated after macrophage depletion. CONCLUSIONS: T-EVs from women with PE could promote preeclampsia by inducing macrophage imbalance polarization, signifying a potential novel interventional target for the prevention and management of PE.

Toxicity from a single injection of human umbilical cord mesenchymal stem cells into rat ovaries.

Intraovarian injection of human umbilical cord mesenchymal stem cells (hUC-MSCs) has been applied and with promising therapeutic effects, but its toxicity and safety remain uncertain. This study evaluated the toxic effects and the affected target organs after a single injection of hUC-MSCs into bilateral rat ovaries. Sixty Sprague-Dawley rats were randomly divided into four groups and intraovarian injected with three different doses of hUC-MSC suspension. Toxicity-related manifestations occurred over the following 14 days postinjection. On day (D)5 and D15, we assessed the clinical pathology; immunotoxicity, including the cytokine IFN-γ, TNF-α, IL-4, and IL-6 levels; the immune organs, and the organ weights. On D5, inflammatory cells mainly infiltrated the ovaries of the low- and medium-dose groups, whereas inflammatory cells infiltrated the oviduct in the medium- and high-dose groups. On D15, inflammatory cells infiltrated the corpus luteal cysts, ovarian sacs and oviducts in each group. Body weights; organ weights; immunotoxicity; clinical pathology and histopathological examinations of the immune organs did not significantly differ among the groups. No obvious hUC-MSC-related clinical symptoms were observed except in the rats that died. The high-dose group exhibited significantly higher mortality than did the control and low-dose groups. Deaths in the high-dose group, who received approximately 50 times the standard clinical dose, were related to the intraovarian hUC-MSC injection. The maximum tolerated dose was approximately ten times the standard clinical dose. The ovary and oviduct may be the target organs for this toxicity. This report provides dosage references and guidance for clinical applications of intraovarian hUC-MSC injections.

Extracellular Vesicle-Mediated Secretion of HLA-E by Trophoblasts Maintains Pregnancy by Regulating the Metabolism of Decidual NK Cells.

Extracellular vesicles derived from trophoblasts (T-EVs) play an important role in pregnancy, but the mechanism is not entirely clear. In this study, we found that HLA-E, which is mostly confined to the cytoplasm of trophoblast cells, was secreted by T-EVs. The level of HLA-E in T-EVs from unexplained recurrent spontaneous abortion (URSA) patients was lower than that in normal pregnancy (NP) and RSA patients who had an abnormal embryo karyotype (AK-RSA). T-EVs promoted secretion of IFN-γ and VEGFα by decidual NK (dNK) cells from URSA patients via HLA-E, VEGFα was necessary for angiogenesis and trophoblast growth, and IFN-γ inhibited Th17 induction. Glycolysis and oxidative phosphorylation (OxPhos) were involved in this process. Glycolysis but not OxPhos of dNK cells facilitated by T-EVs was dependent on mTORC1 activation. Inhibition of T-EV production in vivo increased the susceptibility of mice to embryo absorption, which was reversed by transferring exogenous T-EVs. T-EVs promoted secretion of IFN-γ and VEGFα by dNK cells to maintain pregnancy via Qa-1 in abortion-prone mouse models. This study reveals a new mechanism of pregnancy maintenance mediated by HLA-E via T-EVs.

Estrogen inhibits the growth of colon cancer in mice through reversing extracellular vesicle-mediated immunosuppressive tumor microenvironment.

Postmenopausal women taking estrogen supplements are at a lower risk of advanced colorectal cancer, but the underlying mechanism remains unclear. Thus, this study examined the role of estrogen in colorectal cancer. Estrogen receptor expression levels in in situ colorectal cancer tissue from female patients increased significantly, indicating their estrogen sensitivity. Compared with the sham-operated group, the growth of MC38 tumors was enhanced in ovariectomized mice, which was reversed in ovariectomized mice with E2 supplementation. The PD-L1+ M2-like macrophage, regulatory T (Treg) cell, and myeloid-derived suppressor cell (MDSC) populations significantly increased, and the population of cytotoxic CD8+ T cells declined in MC38 tumors in ovariectomized mice, which were all reversed in ovariectomized mice with E2 supplementation. MC38 cell-derived extracellular vesicles (MC38-EVs), but not EVs derived from MC38 cells treated with E2 (E2-MC38-EVs), were involved in the establishment of immunosuppressive tumor microenvironment. E2-MC38-EVs contained lower TGF-ß1 levels and were less capable of inducing Treg cells than MC38-EVs in vitro. Overall, these results show that estrogen treatment prevents MC38 tumor growth via regulating the tumor immune microenvironment through MC38-EVs.

Hormone Replacement Therapy Reverses Gut Microbiome and Serum Metabolome Alterations in Premature Ovarian Insufficiency.

Objective: We explored the gut microbiome and serum metabolome alterations in patients with premature ovarian insufficiency (POI) and the effects of hormone replacement therapy (HRT) with the aim to unravel the pathological mechanism underlying POI. Methods: Fecal and serum samples obtained from healthy females (HC, n = 10) and patients with POI treated with (n = 10) or without (n = 10) HRT were analyzed using 16S rRNA gene sequencing and untargeted metabolomics analysis, respectively. Peripheral blood samples were collected to detect serum hormone and cytokine levels. Spearman's rank correlation was used to evaluate correlations between sex hormones and cytokines and between the gut microbiota and serum metabolites. To further confirm the correlation between Eggerthella and ovarian fibrosis, the mice were inoculated with Eggerthella lenta (E. lenta) through oral gavage. Results: The abundance of genus Eggerthella significantly increased in the fecal samples of patients with POI compared to that observed in the samples of HCs. This increase was reversed in patients with POI treated with HRT. Patients with POI showed significantly altered serum metabolic signatures and increased serum TGF-ß1 levels; this increase was reversed by HRT. The abundance of Eggerthella was positively correlated with altered metabolic signatures, which were, in turn, positively correlated with serum TGF-ß1 levels in all subjects. Estrogen ameliorated ovarian fibrosis induced by E. lenta in mice. Conclusions: The interactions between the gut microbiota, serum metabolites, and serum TGF-ß1 in patients with POI may play a critical role in the development of POI. HRT not only closely mimicked normal ovarian hormone production in patients with POI but also attenuated gut microbiota dysbiosis and imbalance in the levels of serum metabolites and TGF-ß1, which are reportedly associated with fibrosis. The findings of this study may pave the way for the development of preventive and curative therapies for patients with POI.

Factors associated with the incidence of ectopic pregnancy in women undergoing assisted reproductive treatment.

BACKGROUND: Ectopic pregnancy (EP) is a common complication in women undergoing assisted reproductive treatment, but the underlying causes for this remain unclear. This study aimed to explore factors affecting the incidence of EP in in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI). METHODS: This was a retrospective study on the incidence of EP in IVF/ICSI cycles between January 1, 2013 and December 31, 2017. Patient age, infertility diagnosis (tubal factor or not), primary or secondary infertility, type of cycle (frozen-thawed or fresh), type of embryo(s) transferred (cleavage embryo or blastocyst), number of embryos transferred (one, two, or three), previous history of EP, and endometrial combined thickness were analyzed to explore their relationships with the incidence of EP. Based on clinical typing results, the patients were divided into an EP group or a non-EP group. Categorical variables were analyzed using Chi-squared test or Fisher exact test. Logistic regression analysis was performed to explore their associations with the incidence of EP. RESULTS: The percentage of patients with primary infertility in EP group was significantly lower than that in non-EP group (31.3% vs. 46.7%, χ = 26.032, P < 0.001). The percentage of patients with tubal infertility in EP group was also significantly higher than that in non-EP group (89.2% vs. 63.6%, χ = 77.410, P < 0.001). The percentages of patients with transfer of cleavage-stage embryo or blastocyst (91.4% vs. 84.4%, χ = 10.132, P = 0.001) and different endometrial combined thickness (ECT) (χ = 18.373, P < 0.001) differed significantly between EP and non-EP groups. For patients who had a previous history of one to four EPs, the percentage of patients undergoing transfer of a cleavage-stage embryo was significantly higher in EP group than that in non-EP group (92.2% vs. 77.6%, χ = 13.737, P < 0.001). In multivariate logistic regression analysis, tubal infertility was strongly associated with EP (adjusted odds ratio: 3.995, 95% confidence interval: 2.706-5.897, P < 0.001). CONCLUSIONS: In IVF/ICSI cycles, transfer of a blastocyst-stage embryo, especially for patients with a previous history of EP, reduced the rate of EP. Tubal infertility was strongly associated with EP.

A scaffold laden with mesenchymal stem cell-derived exosomes for promoting endometrium regeneration and fertility restoration through macrophage immunomodulation.

Endometrial traumas may cause intrauterine adhesions (IUAs), leading to infertility. Conventional methods in clinic have not solved the problem of endometrial regeneration in severe cases. Umbilical cord-derived mesenchymal stem cell (UC-MSC)-based therapies have shown some promising achievements in the treatment of IUAs. However, the limitations of potential tumorigenicity, low infusion and low retention are still controversial and restricted the clinical application of MSCs. In contrast, UC-MSC-derived exosomes exhibit a similar function to their source cells and are expected to overcome these limitations. Therefore, a novel and viable cell-free therapeutic strategy by UC-MSC-derived exosomes was proposed in this study. Here, we designed a construct of exosomes and collagen scaffold (CS/Exos) for endometrial regeneration in a rat endometrium-damage model, and investigated the regeneration mechanism through macrophage immunomodulation. The CS/Exos transplantation potently induced (i) endometrium regeneration, (ii) collagen remodeling, (iii) increased the expression of the estrogen receptor α/progesterone receptor, and (iv) restored fertility. Mechanistically, CS/Exos facilitated CD163+ M2 macrophage polarization, reduced inflammation, and increased anti-inflammatory responses in vivo and in vitro. By RNA-seq, miRNAs enriched in exosomes were the main mediator for exosomes-induced macrophage polarization. Overall, we demonstrated that CS/Exos treatment facilitated endometrium regeneration and fertility restoration by immunomodulatory functions of miRNAs. Our research highlights the therapeutic prospects of CS/Exos for the management of IUAs. STATEMENT OF SIGNIFICANCE: Severe endometrial traumas always result in intrauterine adhesions (IUAs) and infertility. The limited outcomes by conventional methods in the clinic make it very important to develop new strategies for endometrium regeneration and fertility restoration. In this study, an exosome-laden scaffold (CS/Exos) was designed and the transplantation of CS/Exos potently induced (i) endometrium regeneration, (ii) collagen remodeling, (iii) increased the expression of the estrogen receptor α/progesterone receptor, and (iv) restored fertility. In mechanism, the construct of CS/Exos facilitated M2 macrophage polarization, reduced inflammation, and increased anti-inflammatory responses. Furthermore, miRNAs enriched in exosomes were the main mediator for exosome-induced macrophage polarization. This study highlights the therapeutic prospects of CS/Exos and the translational application for the management of severe IUAs.