Fructose-1,6-bisphosphate prevents pregnancy loss by inducing decidual COX-2+ macrophage differentiation

BaP/BPDE exposure causes human trophoblast cell dysfunctions and induces miscarriage by up-regulating lnc-HZ06-regulated IL1B

Exposure to environmental BaP or its metabolite BPDE causes trophoblast cell dysfunctions to induce miscarriage (abnormal early embryo loss), which might be generally regulated by lncRNAs. IL1B, a critical inflammatory cytokine, is closely associated with adverse pregnancy outcomes. However, whether IL1B might cause dysfunctions of BaP/BPDE-exposed trophoblast cells to induce miscarriage, as well as its specific epigenetic regulatory mechanisms, is completely unexplored. In this study, we find that BPDE-DNA adducts, trophoblast cell dysfunctions, and miscarriage are closely associated. Moreover, we also identify a novel lnc-HZ06 and IL1B, both of which are highly expressed in BPDE-exposed trophoblast cells, in villous tissues of recurrent miscarriage patients, and in placental tissues of BaP-exposed mice with miscarriage. Both lnc-HZ06 and IL1B suppress trophoblast cell migration/invasion and increase apoptosis. In mechanism, lnc-HZ06 promotes STAT4-mediated IL1B mRNA transcription, enhances IL1B mRNA stability by promoting the formation of METTL3/HuR/IL1B mRNA ternary complex, and finally up-regulates IL1B expression levels. BPDE exposure promotes TBP-mediated lnc-HZ06 transcription, and thus up-regulates IL1B levels. Knockdown of either murine lnc-hz06 (which down-regulates Il1b levels) or murine Il1b could alleviate miscarriage in BaP-exposed mice. Collectively, this study not only discovers novel biological mechanisms and pathogenesis of unexplained miscarriage but also provides novel potential targets for treatment against BaP/BPDE-induced miscarriage.

Impaired IL-27 signaling aggravates macrophage senescence and sensitizes premature ovarian insufficiency induction by high-fat diet

Premature ovarian insufficiency (POI) critically affects female reproductive health, with obesity being a significant and recognized risk factor. Interleukin-27 (IL-27), known for its role in immune modulation and inflammation, has garnered attention in metabolic syndrome research. Nonetheless, the role of these immunometabolic factors on the initiation of POI remains to be unraveled. Our investigation delves into the influence of impaired IL-27 signaling on POI induction, particularly under the challenge of a high-fat diet (HFD). We analyzed patients' serum profiles and established a correlation of increased serum triglycerides with decreased IL-27 levels in POI cases. Experiments on C57BL/6 mice lacking the IL-27 receptor alpha (Il27ra-/-) revealed that when subjected to HFD, these mice developed hallmark POI symptoms. This includes escalated lipid deposition in both liver and ovarian tissues, increased ovarian macrophages cellular aging, and diminished follicle count, all pointing to compromised ovarian function. These findings unveil a novel pathway wherein impaired IL-27 signaling potentiates the onset of POI in the presence of HFD. Understanding the intricate interplay between IL-27, metabolic alterations, and immune dysregulation sheds light on potential therapeutic avenues for managing POI, offering hope for improved reproductive health outcomes.

The novel lnc-HZ12 suppresses autophagy degradation of BBC3 by preventing its interactions with HSPA8 to induce trophoblast cell apoptosis

Abnormal expression of long non-coding RNAs (lncRNAs) is associated with the dysfunctions of human trophoblast cells and the occurrence of miscarriage (abnormal early embryo loss). BBC3/PUMA (BCL2 binding component 3) plays significant roles in regulation of cell apoptosis. However, whether specific lncRNAs might regulate BBC3 in trophoblast cells and further induce apoptosis and miscarriage remains completely unclear. Through screening, we identified a novel lnc-HZ12, which was significantly highly expressed in villous tissues of recurrent miscarriage (RM) patients relative to their healthy control (HC) group. Lnc-HZ12 suppressed chaperone-mediated autophagy (CMA) degradation of BBC3, promoted trophoblast cell apoptosis, and was associated with miscarriage. In mechanism, lnc-HZ12 downregulated the expression levels of chaperone molecules HSPA8 and LAMP2A in trophoblast cells. Meanwhile, lnc-HZ12 (mainly lnc-HZ12-SO2 region in F2 fragment) and HSPA8 competitively bound with the 169RVLYNL174 patch on BBC3, which prevented BBC3 from interactions with HSPA8 and impaired the formation of BBC3-HSPA8-LAMP2A complex for CMA degradation of BBC3. Thus, lnc-HZ12 upregulated the BBC3-CASP9-CASP3 pathway and induced trophoblast cell apoptosis. In villous tissues, lnc-HZ12 was highly expressed, CMA degradation of BBC3 was suppressed, and the apoptosis levels were higher in RM vs HC villous tissues, all of which were associated with miscarriage. Interestingly, knockdown of murine Bbc3 could efficiently suppress placental apoptosis and alleviate miscarriage in a mouse miscarriage model. Taken together, our results indicated that lnc-HZ12 and BBC3 played important roles in trophoblast cell apoptosis and miscarriage and might act as attractive targets for miscarriage treatment.

Discovering a New Drug Against Acute Kidney Injury by Using a Tailored Photoacoustic Imaging Probe

Acute kidney injury (AKI) has become an increasing concern for patients due to the widespread clinical use of nephrotoxic drugs. Currently, the early diagnosis of AKI is still challenging and the available therapeutic drugs cannot meet the clinical demand. Herein, this work has investigated the key redox couple involved in AKI and develops a tailored photoacoustic (PA) imaging probe (AB-DiOH) which can reversibly respond to hypochlorite (ClO-)/glutathione (GSH) with high specificity and sensitivity. This probe enables the real-time monitoring of AKI by noninvasive PA imaging, with better detection sensitivity than the blood test. Furthermore, this probe is utilized for screening nephroprotective drugs among natural products. For the first time, astragalin is discovered to be a potential new drug for the treatment of AKI. After oral administration, astragalin can be efficiently absorbed by the animal body, alleviate kidney injury, and meanwhile induce no damage to other normal tissues. The treatment mechanism of astragalin has also been revealed to be the simultaneous inhibition of oxidative stress, ferroptosis, and cuproposis. The developed PA imaging probe and the discovered drug candidate provide a promising new tool and strategy for the early diagnosis and effective treatment of AKI.

Decidual macrophage: a reversible role in immunotolerance between mother and fetus during pregnancy

The tolerance of the semi-allogeneic fetus by the maternal immune system is an eternal topic of reproductive immunology for ensuring a satisfactory outcome. The maternal-fetal interface serves as a direct portal for communication between the fetus and the mother. It is composed of placental villi trophoblast cells, decidual immune cells, and stromal cells. Decidual immune cells engage in maintaining the homeostasis of the maternal-fetal interface microenvironment. Furthermore, growing evidence has shown that decidual macrophages play a crucial role in maternal-fetal tolerance during pregnancy. As the second largest cell population among decidual immune cells, decidual macrophages are divided into two subtypes: classically activated macrophages (M1) and alternatively activated macrophages (M2). M2 polarization is critical for placentation and embryonic development. Cytokines, exosomes, and metabolites regulate the polarization of decidual macrophages, and thereby modulate maternal-fetal immunotolerance. Explore the initial relationship between decidual macrophages polarization and maternal-fetal immunotolerance will help diagnose and treat the relevant pregnancy diseases, reverse the undesirable outcomes of mothers and infants.

Defective Homologous Recombination Repair By Up-Regulating Lnc-HZ10/Ahr Loop in Human Trophoblast Cells Induced Miscarriage

Human trophoblast cells are crucial for healthy pregnancy. However, whether the defective homologous recombination (HR) repair of dsDNA break (DSB) in trophoblast cells may induce miscarriage is completely unknown. Moreover, the abundance of BRCA1 (a crucial protein for HR repair), its recruitment to DSB foci, and its epigenetic regulatory mechanisms, are also fully unexplored. In this work, it is identified that a novel lnc-HZ10, which is highly experssed in villous tissues of recurrent miscarriage (RM) vs their healthy control group, suppresses HR repair of DSB in trophoblast cell. Lnc-HZ10 and AhR (aryl hydrocarbon receptor) form a positive feedback loop. AhR acts as a transcription factor to promote lnc-HZ10 transcription. Meanwhile, lnc-HZ10 also increases AhR levels by suppressing its CUL4B-mediated ubiquitination degradation. Subsequently, AhR suppresses BRCA1 transcription; and lnc-HZ10 (mainly 1-447 nt) interacts with γ-H2AX; and thus, impairs its interactions with BRCA1. BPDE exposure may trigger this loop to suppress HR repair in trophoblast cells, possibly inducing miscarriage. Knockdown of murine Ahr efficiently recovers HR repair in placental tissues and alleviates miscarriage in a mouse miscarriage model. Therefore, it is suggested that AhR/lnc-HZ10/BRCA1 axis may be a promising target for alleviation of unexplained miscarriage.

Potassium ion efflux induces exaggerated mitochondrial damage and non-pyroptotic necrosis when energy metabolism is blocked

Damage-associated molecular patterns (DAMPs) such as extracellular ATP and nigericin (a bacterial toxin) not only act as potassium ion (K+) efflux inducers to activate NLRP3 inflammasome, leading to pyroptosis, but also induce cell death independently of NLRP3 expression. However, the roles of energy metabolism in determining NLRP3-dependent pyroptosis and -independent necrosis upon K+ efflux are incompletely understood. Here we established cellular models by pharmacological blockade of energy metabolism, followed by stimulation with a K+ efflux inducer (ATP or nigericin). Two energy metabolic inhibitors, namely CPI-613 that targets α-ketoglutarate dehydrogenase and pyruvate dehydrogenase (a rate-limiting enzyme) and 2-deoxy-d-glucose (2-DG) that targets hexokinase, are recruited in this study, and Nlrp3 gene knockout macrophages were used. Our data showed that CPI-613 and 2-DG dose-dependently inhibited NLRP3 inflammasome activation, but profoundly increased cell death in the presence of ATP or nigericin. The cell death was K+ efflux-induced but NLRP3-independent, which was associated with abrupt reactive oxygen species (ROS) production, reduction of mitochondrial membrane potential, and oligomerization of mitochondrial proteins, all indicating mitochondrial damage. Notably, the cell death induced by K+ efflux and blockade of energy metabolism was distinct from pyroptosis, apoptosis, necroptosis or ferroptosis. Furthermore, fructose 1,6-bisphosphate, a high-energy intermediate of glycolysis, significantly suppressed CPI-613+nigericin-induced mitochondrial damage and cell death. Collectively, our data show that energy deficiency diverts NLRP3 inflammasome activation-dependent pyroptosis to Nlrp3-independent necrosis upon K+ efflux inducers, which can be dampened by high-energy intermediate, highlighting a critical role of energy metabolism in cell survival and death under inflammatory conditions.

Potential Causal Association between Plasma Metabolites, Immunophenotypes, and Female Reproductive Disorders: A Two-Sample Mendelian Randomization Analysis

BACKGROUND

While extensive research highlighted the involvement of metabolism and immune cells in female reproductive diseases, causality remains unestablished.

METHODS

Instrumental variables for 486 circulating metabolites (N = 7824) and 731 immunophenotypes (N = 3757) were derived from a genome-wide association study (GWAS) meta-analysis. FinnGen contributed data on 14 female reproductive disorders. A bidirectional two-sample Mendelian randomization study was performed to determine the relationships between exposures and outcomes. The robustness of results, potential heterogeneity, and horizontal pleiotropy were examined through sensitivity analysis.

RESULTS

High levels of mannose were found to be causally associated with increased risks of gestational diabetes (GDM) (OR [95% CI], 6.02 [2.85-12.73], p = 2.55 × 10-6). A genetically predicted elevation in the relative count of circulating CD28-CD25++CD8+ T cells was causally related to increased female infertility risk (OR [95% CI], 1.26 [1.14-1.40], p = 1.07 × 10-5), whereas a high absolute count of NKT cells reduced the risk of ectopic pregnancy (OR [95% CI], 0.87 [0.82-0.93], p = 5.94 × 10-6). These results remained consistent in sensitivity analyses.

CONCLUSIONS

Our study supports mannose as a promising GDM biomarker and intervention target by integrating metabolomics and genomics.

Macrophage plasticity and function in cancer and pregnancy

As the soil of life, the composition and shaping process of the immune microenvironment of the uterus is worth exploring. Macrophages, indispensable constituents of the innate immune system, are essential mediators of inflammation and tissue remodeling as well. Recent insights into the heterogeneity of macrophage subpopulations have renewed interest in their functional diversity in both physiological and pathological settings. Macrophages display remarkable plasticity and switch from one phenotype to another. Intrinsic plasticity enables tissue macrophages to perform a variety of functions in response to changing tissue contexts, such as cancer and pregnancy. The remarkable diversity and plasticity make macrophages particularly intriguing cells given their dichotomous role in either attacking or protecting tumors and semi-allogeneic fetuses, which of both are characterized functionally by immunomodulation and neovascularization. Here, we reviewed and compared novel perspectives on macrophage biology of these two settings, including origin, phenotype, differentiation, and essential roles in corresponding microenvironments, as informed by recent studies on the heterogeneity of macrophage identity and function, as well as their mechanisms that might offer opportunities for new therapeutic strategies on malignancy and pregnancy complications.

Glycolysis: A fork in the path of normal and pathological pregnancy

Glucose metabolism is vital to the survival of living organisms. Since the discovery of the Warburg effect in the 1920s, glycolysis has become a major research area in the field of metabolism. Glycolysis has been extensively studied in the field of cancer and is considered as a promising therapeutic target. However, research on the role of glycolysis in pregnancy is limited. Recent evidence suggests that blastocysts, trophoblasts, decidua, and tumors all acquire metabolic energy at specific stages in a highly similar manner. Glycolysis, carefully controlled throughout pregnancy, maintains a dynamic and coordinated state, so as to maintain the homeostasis of the maternal-fetal interface and ensure normal gestation. In the present review, we investigate metabolic remodeling and the selective propensity of the embryo and placenta for glycolysis. We then address dysregulated glycolysis that occurs in the cellular interactive network at the maternal-fetal interface in miscarriage, preeclampsia, fetal growth restriction, and gestational diabetes mellitus. We provide new insights into the field of maternal-fetal medicine from a metabolic perspective, thus revealing the mystery of human pregnancy.

Insufficient GDF15 expression predisposes women to unexplained recurrent pregnancy loss by impairing extravillous trophoblast invasion

Insufficient extravillous trophoblast (EVT) invasion during early placentation has been shown to contribute to recurrent pregnancy loss (RPL). However, the regulatory factors involved and their involvement in RPL pathogenesis remain unknown. Here, we found aberrantly decreased growth differentiation factor 15 (GDF15) levels in both first-trimester villous and serum samples of unexplained recurrent pregnancy loss (URPL) patients as compared with normal pregnancies. Moreover, GDF15 knockdown significantly reduced the invasiveness of both HTR-8/SVneo cells and primary human EVT cells and suppressed the Jagged-1 (JAG1)/NOTCH3/HES1 pathway activity, and JAG1 overexpression rescued the invasion phenotype of the GDF15 knockdown cells. Induction of a lipopolysaccharide-induced abortion model in mice resulted in significantly reduced GDF15 level in the placenta and serum, as well as increased rates of embryonic resorption, and these effects were reversed by administration of recombinant GDF15. Our study thus demonstrates that insufficient GDF15 level at the first-trimester maternal-foetal interface contribute to the pathogenesis of URPL by impairing EVT invasion and suppressing JAG1/NOTCH3/HES1 pathway activity, and suggests that supplementation with GDF15 could benefit early pregnancy maintenance and reduce the risk of early pregnancy.

Progesterone Activates the Histone Lactylation-Hif1α-glycolysis Feedback Loop to Promote Decidualization

Decidualization is a progesterone-dependent cellular differentiation process that is essential for establishing pregnancy. Robust activation of glycolysis and lactate synthesis during decidualization is remarkable, but their developmental functions remain largely unknown. Herein, we identify that endometrial lactate production plays a critical role in establishing local histone lactylation, a newly identified histone modification, and is important for ensuring normal decidualization. Enhanced endometrial glycolysis is the hallmark metabolic change and is tightly coupled with H4K12la during decidualization. Inhibition of histone lactylation impaired decidualization, in either physiological conception or in vivo and in vitro induced decidualization models. Mechanistic study based on CUT&Tag and ATAC-seq revealed that a transcriptional factor hypoxia-inducible factor 1 α (Hif1α) is the critical regulatory target of H4K12la, and in turn forms an H4K12la-Hif1α-glycolysis feedback loop to drive decidualization. Moreover, we demonstrate that the loop is directly activated by progesterone during decidualization. Our study not only advances the current knowledge of the role of lactate in regulating uterine function, but also establishes a novel functional link among the major endocrine factors, endometrial metabolic change, and epigenetic modification during endometrial remodeling. These findings present valuable clues to develop clinical intervention strategies to improve pregnancy outcomes following both natural conception and assisted reproduction.

BaP/BPDE suppressed endothelial cell angiogenesis to induce miscarriage by promoting MARCHF1/GPX4-mediated ferroptosis

Environmental benzo(a)pyrene (BaP) and its ultimate metabolite BPDE (benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide) are universal and inevitable persistent organic pollutants and endocrine disrupting chemicals. Angiogenesis in placental decidua plays a pivotal role in healthy pregnancy. Ferroptosis is a newly identified and iron-dependent cell death mode. However, till now, BaP/BPDE exposure, ferroptosis, defective angiogenesis, and miscarriage have never been correlated; and their regulatory mechanisms have been rarely explored. In this study, we used assays with BPDE-exposed HUVECs (human umbilical vein endothelial cells), decidual tissues and serum samples collected from unexplained recurrent miscarriage and their matched healthy control groups, and placental tissues of BaP-exposed mouse miscarriage model. We found that BaP/BPDE exposure caused ferroptosis and then directly suppressed angiogenesis and eventually induced miscarriage. In mechanism, BaP/BPDE exposure up-regulated free Fe2+ level and promoted lipid peroxidation and also up-regulated MARCHF1 (a novel E3 ligase of GPX4) level to promote the ubiquitination degradation of GPX4, both of which resulted in HUVEC ferroptosis. Furthermore, we also found that GPX4 protein down-regulated the protein levels of VEGFA and ANG-1, two key proteins function for angiogenesis, and thus suppressed HUVEC angiogenesis. In turn, supplement with GPX4 could suppress ferroptosis, recover angiogenesis, and alleviate miscarriage. Moreover, the levels of free Fe2+ and VEGFA in serum might predict the risk of miscarriage. Overall, this study uncovered the crosstalk among BaP/BPDE exposure, ferroptosis, angiogenesis, and miscarriage, discovering novel toxicological effects of BaP/BPDE on human reproductive health. This study also warned the public to avoid exposure to polycyclic aromatic hydrocarbons during pregnancy to effectively prevent adverse pregnancy outcomes.

Shoutai Wan regulates glycolysis imbalance at the maternal-fetal interface in threatened abortion mice

ETHNOPHARMACOLOGICAL RELEVANCE

Threatened abortion is a common disease among women of childbearing age. Its high incidence rate and unclear etiology, seriously threaten women's physical and mental health. Shoutai Wan (STW) is a traditional Chinese medicine decoction for treating abortion. It has a long history of treating threatened abortion by tonifying the kidney and calming the fetus. However, the mechanism of STW remains unclear.

AIM OF STUDY

To study the mechanism and potential benefit of STW in pregnant mice with hydrocortisone and mifepristone-induced threatened abortion.

MATERIALS AND METHODS

The STW compounds were identified using gas chromatography-mass spectrometry analysis. STW-H, STW-M, or STW-L was separately given 3 mg/ml, 1.5 mg/ml and 0.75 mg/ml STW in the morning, and 2 mg/ml hydrocortisone in the afternoon from gestation day (D) 1-9 and once with 0.4 mg/kg mifepristone on D10. Didroxyprogesterone (0.1 mg/ml) and equal dose pure water were used to replace STW in didroxyprogesterone (DYD) group and model group respectively. The control group used pure water to replace STW, hydrocortisone, and mifepristone. We performed morphological and histological analyses of the maternal-fetal interface on day 10.

RESULTS

The embryo loss rate in the STW-H and DYD groups was lower than that in the model group. Hematoxylin and eosin (HE) staining suggested that the morphology of maternal-fetal interface was improved in the STW-H and DYD groups. Immunohistochemical (IHC), Quantitative Reverse Transcription Polymerase Chain Reactionstaining (qRT-PCR), and Western blot (WB) results indicated that HIF-1α expression in the maternal-fetal interface of the STW-H and DYD groups was higher than that in model group. The activities of HK, PKM, LDH and the concentration of lactic acid in the STW-H and DYD groups were higher than those in model group. Furthermore, the protein and mRNA levels of HK2, PKM2, LDHA, MCT4, and GPR81 were higher in the STW-H and DYD groups than those in the model group.

CONCLUSIONS

STW can reduce the pregnancy loss rate by regulating the glycolysis balance at the maternal-fetal interface of kidney deficiency threatened abortion model mice.

Energy metabolism and maternal-fetal tolerance working in decidualization

One pivotal aspect of early pregnancy is decidualization. The decidualization process includes two components: the differentiation of endometrial stromal cells to decidual stromal cells (DSCs), as well as the recruitment and education of decidual immune cells (DICs). At the maternal-fetal interface, stromal cells undergo morphological and phenotypic changes and interact with trophoblasts and DICs to provide an appropriate decidual bed and tolerogenic immune environment to maintain the survival of the semi-allogeneic fetus without causing immunological rejection. Despite classic endocrine mechanism by 17 β-estradiol and progesterone, metabolic regulations do take part in this process according to recent studies. And based on our previous research in maternal-fetal crosstalk, in this review, we elaborate mechanisms of decidualization, with a special focus on DSC profiles from aspects of metabolism and maternal-fetal tolerance to provide some new insights into endometrial decidualization in early pregnancy.

IL-27 deficiency inhibits proliferation and invasion of trophoblasts via the SFRP2/Wnt/β-catenin pathway in fetal growth restriction

Background: Fetal growth restriction (FGR) is characterized by restricted fetal growth and dysregulated placental development. The etiology and pathogenesis still remain elusive. IL-27 shows multiple roles in regulating various biological processes, however, how IL-27 involves in placentation in FGR pregnancy hasn't been demonstrated. Methods: The levels of IL-27 and IL-27RA in FGR and normal placentae were determined by immunohistochemistry, western blot and RT-PCR. HTR-8/SVneo cells and Il27ra^-/- murine models have been adopted to evaluate the effects of IL-27 on the bio-functions of trophoblast cells. GO enrichment and GSEA analysis were performed to explore the underlying mechanism. Findings: IL-27 and IL-27RA was lowly expressed in FGR placentae and administration of IL-27 on HTR-8/SVneo could promote its proliferation, migration and invasion. Comparing with wildtypes, Il27ra^-/- embryos were smaller and lighter, and the placentae from which were poorly developed. In mechanism, the molecules of canonical Wnt/β-catenin pathway (CCND1, CMYC, SOX9) were downregulated in Il27ra^-/- placentae. In contrast, the expression of SFRP2 (negative regulator of Wnt) was increased. Overexpression of SFRP2 in vitro could impair trophoblast migration and invasion capacity. Interpretation: IL-27/IL-27RA negatively regulates SFRP2 to activate Wnt/β-catenin, and thus promotes migration and invasion of trophoblasts during pregnancy. However, IL-27 deficiency may contribute to the development of FGR by restricting the Wnt activity.

An IGF1-expressing endometrial stromal cell population is associated with human decidualization

BACKGROUND

Decidualization refers to the process of transformation of endometrial stromal fibroblast cells into specialized decidual stromal cells that provide a nutritive and immunoprivileged matrix essential for blastocyst implantation and placental development. Deficiencies in decidualization are associated with a variety of pregnancy disorders, including female infertility, recurrent implantation failure (RIF), and miscarriages. Despite the increasing number of genes reportedly associated with endometrial receptivity and decidualization, the cellular and molecular mechanisms triggering and underlying decidualization remain largely unknown. Here, we analyze single-cell transcriptional profiles of endometrial cells during the window of implantation and decidual cells of early pregnancy, to gains insights on the process of decidualization.

RESULTS

We observed a unique IGF1⁺ stromal cell that may initiate decidualization by single-cell RNA sequencing. We found the IL1B⁺ stromal cells promote gland degeneration and decidua hemostasis. We defined a subset of NK cells for accelerating decidualization and extravillous trophoblast (EVT) invasion by AREG-IGF1 and AREG-CSF1 regulatory axe. Further analysis indicates that EVT promote decidualization possibly by multiply pathways. Additionally, a systematic repository of cell-cell communication for decidualization was developed. An aberrant ratio conversion of IGF1⁺ stromal cells to IGF1R⁺ stromal cells is observed in unexplained RIF patients.

CONCLUSIONS

Overall, a unique subpopulation of IGF1⁺ stromal cell is involved in initiating decidualization. Our observations provide deeper insights into the molecular and cellular characterizations of decidualization, and a platform for further development of evaluation of decidualization degree and treatment for decidualization disorder-related diseases.

Understanding recurrent pregnancy loss: recent advances on its etiology, clinical diagnosis, and management

Recurrent pregnancy loss (RPL) has become an important reproductive health issue worldwide. RPL affects about 2%-3% of reproductive-aged women, and makes serious threats to women's physical and mental health. However, the etiology of approximately 50% of RPL cases remains unknown (unexplained RPL), which poses a big challenge for clinical management of these patients. RPL has been widely regarded as a complex disease where its etiology has been attributed to numerous factors. Heretofore, various risk factors for RPL have been identified, such as maternal ages, genetic factors, anatomical structural abnormalities, endocrine dysfunction, prethrombotic state, immunological factors, and infection. More importantly, development and applications of next generation sequencing technology have significantly expanded opportunities to discover chromosomal aberrations and single gene variants responsible for RPL, which provides new insight into its pathogenic mechanisms. Furthermore, based upon patients' diagnostic evaluation and etiologic diagnosis, specific therapeutic recommendations have been established. This review will highlight current understanding and recent advances on RPL, with a special focus on the immunological and genetic etiologies, clinical diagnosis and therapeutic management.

Research on the Mechanism of Asperosaponin VI for Treating Recurrent Spontaneous Abortion by Bioinformatics Analysis and Experimental Validation

Asperosaponin VI (AS6), as the quality marker of Dipsaci Radix, is verified to exert therapeutic effect on alleviating recurrent spontaneous abortion (RSA). However, due to the lack of relevant research, its molecular mechanism is still unclear. We retrieved targets for AS6 and RSA, and then used their overlapped targets for PPI analysis. In addition, we used GO and KEGG enrichment analyses, and molecular docking to investigate the anti-RSA mechanisms of AS6. Furthermore, we conducted in vitro experiments to validate the predictions of network pharmacology. Results showed that a total of 103 AS6-associated targets and 2084 RSA-associated targets, with 49 targets overlapped. GO enrichment analysis showed 845 significant biological processes like decidualization, while KEGG pathway enrichment analysis revealed 76 significant entries including 18 signaling pathways, which were closely linked to PI3K-Akt, HIF-1, TNF, IL-17, and VEGF signaling pathways, etc. Molecular docking findings verified that AS6 had tight link with the key targets including JUN, CASP3, STAT3, SRC, and PTGS2. Notably, in vitro experiments revealed that AS6 treatment could exert lower expressions of JUN, pro-CASP3, CASP3, STAT3, SRC, and PTGS2 in decidual cells compared with progesterone despite the expressions of STAT3, SRC, and PTGS2 with no significant difference, and mifepristone could interfere with the effects. In general, numerous targets and multiple pathways involve during the process of AS6 treatment against RSA. Moreover, our in vitro research first reported that AS6 may regulate the expressions of key targets (JUN, CASP3, STAT3, SRC, and PTGS2) in decidual cells to promote decidualization, thus treating RSA.

The metabolic characteristic of decidual immune cells and their unique properties in pregnancy loss

Maternal tolerance to semi- or fully allograft conceptus is a prerequisite for the maintenance of pregnancy. Once this homeostasis is disrupted, it may result in pregnancy loss. As a potential approach to prevent pregnancy loss, targeting decidual immune cells (DICs) at the maternal-fetal interface has been suggested. Although the phenotypic features and functions of DIC have been extensively profiled, the regulatory pathways for this unique immunological adaption have yet to be elucidated. In recent years, a pivotal mechanism has been highlighted in the area of immunometabolism, by which the changes in intracellular metabolic pathways in DIC and interaction with the adjacent metabolites in the microenvironment can alter their phenotypes and function. More inspiringly, the manipulation of metabolic profiling in DIC provides a novel avenue for the prevention and treatment of pregnancy loss. Herein, this review highlights the major metabolic programs (specifically, glycolysis, ATP-adenosine metabolism, lysophosphatidic acid metabolism, and amino acid metabolism) in multiple immune cells (including decidual NK cells, macrophages, and T cells) and their integrations with the metabolic microenvironment in normal pregnancy. Importantly, this perspective may help to provide a potential therapeutic strategy for reducing pregnancy loss via targeting this interplay.