Maternal IL-33 critically regulates tissue remodeling and type 2 immune responses in the uterus during early pregnancy in mice

Decreased membrane-bound suppressor of tumorigenicity 2 (ST2) but not soluble ST2 was associated with women with recurrent pregnancy loss and recurrent implantation failure compared to controls

Increased infiltration of immune effectors, including mast cells and natural killer cells in the mid-luteal endometrium was reported in women with recurrent pregnancy loss and repeated implantation failure. Interleukin-33 plays an important role in the cellular activation of mast cells and natural killer cells. This study investigated the endometrial IL-33/ST2 axis and its role in mast cell activation in women with RPL and RIF during the mid-luteal phase. Gene expression of ST2 was significantly decreased in RPL and RIF patients compared to normal fertile controls (Mean ± SE, 0.46 ± 0.08, 0.44 ± 0.09, 1.25 ± 0.46, P < 0.007). No differences were found in ST2/IL-33 mRNA expression ratios, IL-33, and TPSAB1 mRNA expression. Western blot analysis revealed a decreased amount of membrane-bound ST2 in RPL and RIF in the endometrium compared to controls (0.09 ± 0.02, 0.12 ± 0.08, 0.28 ± 0.07, P < 0.05). No difference was found in soluble ST2 levels. Evaluation of the ST2/IL-33 protein ratios showed no significance between groups. No differences were found in IL-33 or tryptase protein levels. A correlation analysis was performed between mRNA expression levels of IL-33, ST2, and TPSAB1 in relation to genes associated with decidualization; IL-33 was correlated with CD3E, GZMB, NCAM1, PRF1, RORC, SGK1, and TGFB1 in the RPL group and associated with CDKN2A, IL18, SLC2A1, and VEGFA in controls. Decreased amount of membrane-bound ST2 may lead to the decreased physiologic activity of IL-33 on immune cells within patients with RPL and RIF; this may lead to alterations in uNK cells contributing to immune dysregulation in the endometrium.

The role of necroptosis in pathological pregnancies: Mechanisms and therapeutic opportunities

Necroptosis, a distinctive form of programmed cell death differs mechanistically from apoptosis pyroptosis, and autophagy, is characterized by the activation of receptor-interacting protein kinases (RIPK1/RIPK3) and their downstream effector, mixed lineage kinase domain-like protein (MLKL). This programmed cell death pathway serves as a crucial mediator of inflammatory responses and has been implicated in the pathogenesis of diverse pathological conditions. Recent evidence has implicated dysregulated necroptosis in the pathogenesis of severe pregnancy complications, including preeclampsia (PE), fetal growth restriction (FGR), recurrent spontaneous abortion (RSA), and gestational diabetes mellitus (GDM). In these disorders, necroptosis promotes placental dysfunction through multiple interconnected mechanisms: amplification of pro-inflammatory cytokine cascades, aberrant immune activation, disruption of plasma membrane integrity, and subsequent tissue injury.These pregnancy-related pathologies consistently demonstrate elevated necroptotic signatures, correlating with adverse maternal-fetal outcomes. This comprehensive review synthesizes current understanding of the molecular mechanisms underlying necroptosis, with particular emphasis on its pivotal role in the etiopathogenesis of pregnancy-related disorders. Furthermore, we critically evaluate the therapeutic potential of targeting the necroptotic signaling axis, providing novel perspectives for developing targeted interventions to improve clinical outcomes in complicated pregnancies.

CD163 + M2-like monocytes increase in pregnant women with first-attempted frozen embryo transfer

Macrophages play a vital role in endometrial receptivity and embryo implantation. However, it remains unclear if macrophages in peripheral blood is associated with pregnancy outcomes of frozen embryo transfer during implantation window. 50 patients preparing for the first time of frozen embryo transfer (FET) and 17 patients with recurrent implantation failure (RIF) from December 2022 to March 2023 were included in our present study. The percentages of peripheral macrophages and other immune cells (B-cell, T-cell, NK cell) were evaluated by flow cytometry. The concentrations of cytokines were verified with an IMMULITE 1000 Immunoassay System. FET patients were categorized into pregnant and nonpregnant groups according to clinical outcomes, respectively. The proportion of peripheral CD68+CD163+ M2 macrophages was increased in pregnant women than in nonpregnant women among the first time of FET patients. CD4+ T helper cells were positively correlated with M2-like macrophages in these women. The pregnancy rate of women with higher peripheral CD163 + M2-like monocytes increased compared with women with lower peripheral CD163 + M2-like monocytes in an independent cohort according to the cutoff value of CD163 + M2-like monocytes in ROC curve. Our findings revealed that peripheral CD163+ M2 macrophages in implantation window were associated with pregnancy outcomes. This indicated that the importance of peripheral M2 macrophages at the implantation site for pregnancy success.

Inflammatory Indices in First Trimester as Predictors of Gestational Diabetes Mellitus and Adverse Pregnancy Outcomes

OBJECTIVES

To explore the association between systemic inflammatory markers (systemic inflammation response index [SIRI], systemic immune inflammation index [SII], interleukin [IL]-33, and soluble tumorigenicity 2 [sST2]) and gestational diabetes mellitus (GDM), as well as adverse pregnancy outcomes (APOs), and to assess the impact of glycemic control on these relationships.

METHODS

A total of 777 participants were included, comprising 476 women with GDM and 301 without. Clinical characteristics, inflammatory markers, and pregnancy outcomes were analyzed. Logistic regression was employed to assess the risk of GDM and APOs associated with elevated inflammatory indices and glycemic control. Diagnostic performance was evaluated using receiver operating characteristic (ROC) curves.

RESULTS

Women with GDM exhibited significantly higher levels of SII, SIRI, IL-33, and sST2. Multivariate logistic regression demonstrated that SII, SIRI, IL-33, and sST2 were independent predictors of GDM. Moreover, the highest tertiles of SII, SIRI, and IL-33 were strongly associated with APO risk. ROC analysis revealed that SII had the highest predictive value for GDM (AUC 0.763), while IL-33 had the greatest predictive accuracy for APOs (AUC 0.669). Effective glycemic control was associated with reduced inflammatory marker levels (SII, aOR 3.9; SIRI, aOR 3.7; IL-33, aOR 2.4) and a decreased risk of APOs and large-for-gestational-age (LGA) infants in women with GDM.

CONCLUSIONS

Elevated SII, SIRI, IL-33, and sST2 are significant predictors of GDM and APOs, with SII being the most robust predictor of GDM and IL-33 for APOs. Glycemic control reduces inflammation and may improve pregnancy outcomes in women with GDM.

ARID1A: Multiple functions in human pregnancy

AT-rich interacting domain containing respectively protein 1 A (ARID1A), a key member of the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex, has been shown to play an important role in various physiological processes and diseases including female reproductive tumors, such as ovarian cancer and breast cancer. In addition to the studies regarding ARID1A expression and function in cancer, recent findings elucidate its important role in maintaining normal tissue homeostasis and cell differentiation by controlling chromatin remodeling and transcription factors recruitment. In the context of human pregnancy, ARID1A has been implicated in several pregnancy-related complications, including gestational diabetes, preeclampsia, and intrauterine growth restriction. This review examines the current research on the role of ARID1A in pregnancy, highlighting its potential as a biomarker and therapeutic target for these complications. Understanding the involvement of ARID1A in placental function and pregnancy-related disorders may provide valuable insights for the development of novel diagnostic and therapeutic strategies.

Inhibiting mechanotransduction prevents scarring and yields regeneration in a large animal model

Modulating mechanotransduction by inhibiting yes-associated protein (YAP) in mice yields wound regeneration without scarring. However, rodents are loose-skinned and fail to recapitulate key aspects of human wound repair. We sought to elucidate the effects of YAP inhibition in red Duroc pig wounds, the most human-like model of scarring. We show that one-time treatment with verteporfin, a YAP inhibitor, immediately after wounding is sufficient to prevent scarring and to drive wound regeneration in pigs. By performing single-cell RNA sequencing (scRNA-seq) on porcine wounds in conjunction with spatial proteomic analysis, we found perturbations in fibroblast dynamics with verteporfin treatment and the presence of putative pro-regenerative/profibrotic fibroblasts enriched in regenerating/scarring pig wounds, respectively. We also identified differences in enriched myeloid cell subpopulations after treatment and linked this observation to increased elaboration of interleukin-33 (IL-33) in regenerating wounds. Finally, we validated our findings in a xenograft wound model containing human neonatal foreskin engrafted onto nude mice and used scRNA-seq of human wound cells to draw parallels with fibroblast subpopulation dynamics in porcine wounds. Collectively, our findings provide support for the clinical translation of local mechanotransduction inhibitors to prevent human skin scarring, and they clarify a YAP/IL-33 signaling axis in large animal wound regeneration.

Decidual stromal cells: fibroblasts specialized in immunoregulation during pregnancy

Decidual stromal cells (DSCs) are involved in immunoregulatory mechanisms that prevent fetal rejection by the mammalian maternal immune system. Recent studies using single-cell RNA sequencing demonstrated the existence of different types of human and mouse DSCs, highlighting corresponding differentiation (decidualization) pathways, and suggesting their involvement in the immune response during normal and pathological pregnancy. DSCs may be considered tissue-specialized fibroblasts because both DSCs and fibroblasts share phenotypic and functional similarities in immunologically challenged tissues, especially in terms of their immune functions. Indeed, fibroblasts can setup, support, and suppress immune responses and these functions are also performed by DSCs. Moreover, fibroblasts and DSCs can induce ectopic foci as tertiary lymphoid structures (TLSs), and endometriosis, respectively. Thus, understanding DSC immunoregulatory functions is of timely relevance.

TRα1 mutant suppresses KLF9 to cause endometrial metaplasia with ectopic IL-33 expression leading to uterine fibrosis and infertility

Thyroid hormone receptors (TRs) mediate the genomic actions of thyroid hormone. Mutations of THRA gene cause a human disease known as resistance to thyroid hormone (RTHα). We created a mouse model expressing a dominant negative mutated TRα1 (Thra1PV/+ mice) that exhibits growth retardation, bone abnormalities, constipation, and anemia, as found in RTHα patients. In addition, female Thra1PV/+ mice exhibit decreased fertility. In the present study, we aimed to characterize the molecular events leading to infertility. Histologically, there was progressive uterine atrophy in Thra1PV/+ mutant mice, characterized by squamous metaplasia of the endometrial mucosa and endometrial fibrosis. RNA-seq analysis of laser-captured micro-dissected endometrium and spatial transcriptomics revealed a key role for Krüppel-like factor (Klf9), a directly-regulated TR target gene, in normal endometrial differentiation. Klf9 was suppressed in the endometrium of mice harboring mutated TRα1 and pathway analysis revealed that deficient Klf9 signaling was associated with squamous differentiation, consistent with the endometrial metaplasia observed histologically. Further, we showed that this metaplastic endometrial mucosa was the source of ectopic IL-33, which was associated with increased T-cell infiltrates, destruction of glands, and endometrial fibrosis. Our studies provide new insights to understand uterine epithelial morphogenesis and how thyroid dysfunction could lead to female infertility.

YAP1 and WWTR1 are required for murine pregnancy initiation

In brief

The HIPPO signaling effectors YAP1 and WWTR1 are required for murine pregnancy initiation, and mutation of these factors compromises the decidualization response and overall pregnancy success.

Abstract

Endometrial stromal cell decidualization is required for pregnancy success. Although this process is integral to fertility, many of the intricate molecular mechanisms contributing to decidualization remain undefined. One pathway that has been implicated in endometrial stromal cell decidualization in humans in vitro is the HIPPO signaling pathway. Two previously conducted studies showed that the effectors of the HIPPO signaling pathway YAP1 and WWTR1 are required for decidualization of primary endometrial stromal cells in vitro. To investigate the in vivo role of YAP1 and WWTR1 in decidualization and pregnancy initiation, we generated progesterone receptor Cre-mediated mutation of a combination of Yap1 and Wwtr1 alleles. Female Yap1 and Wwtr1 triple allele mutants exhibited subfertility, a compromised decidualization response, decreased endometrial receptivity, delayed embryonic development and a unique transcriptional profile at 7.5 days post-coitus (dpc). Bulk mRNA sequencing revealed aberrant maternal remodeling evidenced by significant alterations in extracellular matrix-encoding genes at 7.5 dpc in mutant dams and enrichment for terms associated with fertility-compromising diseases such as pre-eclampsia and endometriosis. In addition, differentially expressed genes overlapped directionally with estrogen receptor- and epidermal growth factor receptor-regulated genes as identified by microarray. Our results indicate that Yap1 and Wwtr1 are necessary for successful mammalian pregnancy initiation.

Multi-locus high-risk alleles association from interleukin's genes with female infertility and certain comorbidities

Objective There is evidence that cytokine genes' single nucleotide polymorphisms could be the reasons behind female infertility. This study aimed to identify the role for Interleukin33 rs1048274 (G > A) and rs16924243 (T > C), Interleukin22 rs1397852121 (C > T), rs1295978671 (C > T) and rs2227483 (A > T), Interleukin17A rs2275913 (G > A,C) and Interleukin17F rs763780 (T > C), Interleukin13 1512 (A > C) and IL13 2044 (G > A), and Interleukin4 rs2243250 (C > T) and rs2070874 (C > T) gene polymorphisms in female infertility to gain a richly more detailed understanding of its genetic predisposition. Five distinct groups, each comprising 200 infertile women and 200 age-matched fertile controls, were recruited to each Interleukins (33, 22, 17, 13 and 4) in this case-control study and were genotyped by using an amplification refractory mutation system. Statistical analysis is conducted by SPSS software V. 22 and using Chi-square (χ2) and logistic regression tests. Strength of association was estimated by multiple-comparison correction, population structure test and Haplotype analysis. The study was approved by the Academic Ethics Committee and each enrolled patient signed an informed consent.Results Our statistical results revealed risk alleles in all of the substitution lines for women infertility. Current findings provided evidence that in the presence of Interleukin33 Ap-value rs1048274 = 0.002 and Cp-value rs16924243 < 0.0001, Interleukin 22Tp-value rs1397852121 < 0.0001 and Tp-value rs2227483 = 0.000, Interleukin17A Ap-value rs2275913 = 0.003 and Interleukin17F Cp-value rs763780 = 0.000 and Interleukin13 Cp-value 1512 = 0.000 and Ap-value 2044 = 0.003, Interleukin4 Tp-value rs2243250 = 0.001 and Tp-value rs2070874 = 0.009 risk alleles, risk genotype also were significantly associated with increased chances of developing infertility. The relationship between risk genotypes and several well-established infertility risk factors including, polycystic ovary syndrome, premature ovarian failure, oophorectomy, diminished ovarian reserve, endometriosis, uterine fibroids, ovarian cysts, uterine polyps, fallopian tube blockage and thyroid dysfunction, also exhibited. This study suggests the significant role of interleukin gene polymorphisms in human reproductive success.

Infertility, IL-17, IL-33 and Microbiome Cross-Talk: The Extended ARIA-MeDALL Hypothesis

Infertility, defined as the inability to obtain pregnancy after 12 months of regular unprotected sexual intercourse, has increased in prevalence over the past decades, similarly to chronic, allergic, autoimmune, or neurodegenerative diseases. A recent ARIA-MeDALL hypothesis has proposed that all these diseases are linked to dysbiosis and to some cytokines such as interleukin 17 (IL-17) and interleukin 33 (IL-33). Our paper suggests that endometriosis, a leading cause of infertility, is linked to endometrial dysbiosis and two key cytokines, IL-17 and IL-33, which interact with intestinal dysbiosis. Intestinal dysbiosis contributes to elevated estrogen levels, a primary factor in endometriosis. Estrogens strongly activate IL-17 and IL-33, supporting the existence of a gut-endometrial axis as a significant contributor to infertility.

IL-33 Signaling Inhibition Leads to a Preeclampsia-Like Phenotype in Pregnant Rats

PROBLEM

Preeclampsia (PE) is a hypertensive pregnancy disorder that is a leading cause of maternal and fetal morbidity and mortality characterized by maternal vascular dysfunction, oxidative stress, chronic immune activation, and excessive inflammation. No cure exists beyond delivery of the fetal-placental unit and the mechanisms driving pathophysiology are not fully understood. However, aberrant immune responses have been extensively characterized in clinical studies and shown to mediate PE pathophysiology in animal studies. One pathway that may mediate aberrant immune responses in PE is deficiencies in the IL-33 signaling pathway. In this study, we aim to investigate the impact of IL-33 signaling inhibition on cNK, TH17, and TReg populations, vascular function, and maternal blood pressure during pregnancy.

METHOD OF STUDY

In this study, IL-33 signaling was inhibited using two different methods: intraperitoneal administration of recombinant ST2 (which acts as a decoy receptor for IL-33) and administration of a specific IL-33 neutralizing antibody. Maternal blood pressure, uterine artery resistance index, renal and placental oxidative stress, cNK, TH17, and TReg populations, various cytokines, and pre-proendothelin-1 levels were measured.

RESULTS

IL-33 signaling inhibition increased maternal blood pressure, uterine artery resistance, placental and renal oxidative stress. IL-33 signaling inhibition also increased placental cNK and TH17 and renal TH17 cells while decreasing placental TReg populations. IL-33 neutralization increased circulating cNK and TH17s and decreased circulating TRegs in addition to increasing pre-proendothelin-1 levels.

CONCLUSIONS

Data presented in this study demonstrate a role for IL-33 signaling in controlling vascular function and maternal blood pressure during pregnancy possibly by mediating innate and adaptive immune inflammatory responses, identifying the IL-33 signaling pathway as a potential therapeutic target for managing preeclampsia.

A Galectin-9-Driven CD11chigh Decidual Macrophage Subset Suppresses Uterine Vascular Remodeling in Preeclampsia

BACKGROUND

Preeclampsia is a serious disease of pregnancy that lacks early diagnosis methods or effective treatment, except delivery. Dysregulated uterine immune cells and spiral arteries are implicated in preeclampsia, but the mechanistic link remains unclear.

METHODS

Single-cell RNA sequencing and spatial transcriptomics were used to identify immune cell subsets associated with preeclampsia. Cell-based studies and animal models including conditional knockout mice and a new preeclampsia mouse model induced by recombinant mouse galectin-9 were applied to validate the pathogenic role of a CD11chigh subpopulation of decidual macrophages (dMφ) and to determine its underlying regulatory mechanisms in preeclampsia. A retrospective preeclampsia cohort study was performed to determine the value of circulating galectin-9 in predicting preeclampsia.

RESULTS

We discovered a distinct CD11chigh dMφ subset that inhibits spiral artery remodeling in preeclampsia. The proinflammatory CD11chigh dMφ exhibits perivascular enrichment in the decidua from patients with preeclampsia. We also showed that trophoblast-derived galectin-9 activates CD11chigh dMφ by means of CD44 binding to suppress spiral artery remodeling. In 3 independent preeclampsia mouse models, placental and plasma galectin-9 levels were elevated. Galectin-9 administration in mice induces preeclampsia-like phenotypes with increased CD11chigh dMφ and defective spiral arteries, whereas galectin-9 blockade or macrophage-specific CD44 deletion prevents such phenotypes. In pregnant women, increased circulating galectin-9 levels in the first trimester and at 16 to 20 gestational weeks can predict subsequent preeclampsia onset.

CONCLUSIONS

These findings highlight a key role of a distinct perivascular inflammatory CD11chigh dMφ subpopulation in the pathogenesis of preeclampsia. CD11chigh dMφ activated by increased galectin-9 from trophoblasts suppresses uterine spiral artery remodeling, contributing to preeclampsia. Increased circulating galectin-9 may be a biomarker for preeclampsia prediction and intervention.

Neuroserpin, IL-33 and IL-17A as potential markers of mild symptoms of depressive syndrome in Toxoplasma gondii-infected pregnant women

Introduction

Depressive syndrome (DS) is a common complication during pregnancy and the postpartum period, and is triggered by multiple organic/genetic and environmental factors. Clinical and biochemical follow-up is essential for the early diagnosis and prognosis of DS. The protozoan Toxoplasma gondii causes infectious damage to the fetus during parasite primary-infection. However, in long-term infections, pregnant women develop immune protection to protect the fetus, although they remain susceptible to pathological or inflammatory effects induced by T. gondii. This study aimed to investigate plasma inflammatory biomarkers in pregnant women seropositive and seronegative for T. gondii, with diagnoses of minor and moderate/severe DS.

Methods

Pregnant women (n=45; age=18-39 years) were recruited during prenatal care at health centers in Ouro Preto, Minas Gerais, Brazil. Participants were asked to complete a socio-demographic questionnaire to be submitted to well-standardized DS scale calculators (Beck Depression Inventory Questionnaire, Edinburgh Postnatal Depression Scale, and Major Depressive Episode Module). Additionally, 4 mL of blood was collected for plasma neuroserpin, CCL2, IL-17A, and IL-33 analysis.

Results

Pregnant volunteers with chronic T. gondii contact were all IgG+ (44%; n=21) and exhibited increased plasma IL-33, IL-17A, and neuroserpin levels, but not CCL2, compared to uninfected pregnant women. Using Beck's depression inventory, we observed an increase in plasma IL-17A and IL-33 in women with T. gondii infeCction diagnosed with mild DS, whereas neuroserpin was associated with minor and moderate/severe DS.

Discussion

Our data suggest a close relationship between DS in pregnant women with chronic T. gondii infection and neurological conditions, which may be partially mediated by plasma neuroserpin, IL-33, and IL-17A levels.

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.

IL-33 supplementation improves uterine artery resistance and maternal hypertension in response to placental ischemia

Preeclampsia (PE), a leading cause of maternal/fetal morbidity and mortality, is a hypertensive pregnancy disorder with end-organ damage that manifests after 20 wk of gestation. PE is characterized by chronic immune activation and endothelial dysfunction. Clinical studies report reduced IL-33 signaling in PE. We use the Reduced Uterine Perfusion Pressure (RUPP) rat model, which mimics many PE characteristics including reduced IL-33, to identify mechanisms mediating PE pathophysiology. We hypothesized that IL-33 supplementation would improve blood pressure (BP), inflammation, and oxidative stress (ROS) during placental ischemia. We implanted intraperitoneal mini-osmotic pumps infusing recombinant rat IL-33 (1 µg/kg/day) into normal pregnant (NP) and RUPP rats from gestation day 14 to 19. We found that IL-33 supplementation in RUPP rats reduces maternal blood pressure and improves the uterine artery resistance index (UARI). In addition to physiological improvements, we found decreased circulating and placental cytolytic Natural Killer cells (cNKs) and decreased circulating, placental, and renal TH17s in IL-33-treated RUPP rats. cNK cell cytotoxic activity also decreased in IL-33-supplemented RUPP rats. Furthermore, renal ROS and placental preproendothelin-1 (PPET-1) decreased in RUPP rats treated with IL-33. These findings demonstrate a role for IL-33 in controlling vascular function and maternal BP during pregnancy by decreasing inflammation, renal ROS, and PPET-1 expression. These data suggest that IL-33 may have therapeutic potential in managing PE.NEW & NOTEWORTHY Though decreased IL-33 signaling has been clinically associated with PE, the mechanisms linking this signaling pathway to overall disease pathophysiology are not well understood. This study provides compelling evidence that mechanistically links reduced IL-33 with the inflammatory response and vascular dysfunction observed in response to placental ischemia, such as in PE. Data presented in this study submit the IL-33 signaling pathway as a possible therapeutic target for the treatment of PE.

Comparison of serum levels of interleukin 33 in combination with serum levels of C-reactive protein, Immunoglobulin G, Immunoglobulin A, and Immunoglobulin M in recurrent pregnancy loss: A case-control study

Background

One of the critical cases of recurrent pregnancy loss is immunological factors, whereas obtaining effective prevention or treatment is necessary for cognition of reasons.

Objective

In this study, we tried to evaluate some immunological factors related to recurrent pregnancy loss.

Materials and Methods

This case-control study was conducted on 66 women at the age of 18-35 yr who were referred to the Clinic of Gynecology and Obstetrics, Ali Ibn Abi Taleb hospital, Zahedan, Iran, from August-December 2019. Interleukin 33 (IL-33) serum levels were measured using enzyme-linked immunosorbent assay. Immunoglobulin G, Immunoglobulin A, Immunoglobulin M (IgM), and C-reactive protein levels were measured by serology and hematology methods.

Results

The mean age of total participants was 30.8 ± 3.80 yr. The mean serum IL-33 in the case group was 318.5 ± 254.1 pg/ml and was lower than the control group (354.2 ± 259.9 pg/ml), which was not statistically significant (p = 0.52). The level of C-reactive protein in the case and control was not significantly different (p = 0.27), and Immunoglobulin A and Immunoglobulin G in the case and control were also not significantly different (p = 0.46, and p = 0.16, respectively), but there were significant differences (p = 0.003) between the level of the IgM in the case and control groups.

Conclusion

No statistically significant difference was observed in the IL-33 serum level, for at least 4-6 months after the last abortion in the case group and the final live birth in the control group. In contrast, serum levels of IgM were statistically significant. Finally, the need for more studies is felt according to the different results of the previous studies in this field.

Interleukin-33/serum stimulation-2 pathway: Regulatory mechanisms and emerging implications in immune and inflammatory diseases

Interleukin (IL)- 33, a nuclear factor and pleiotropic cytokine of the IL-1 family, is gaining attention owing to its important role in chronic inflammatory and autoimmune diseases. This review extends our knowledge of the effects exerted by IL-33 on target cells by binding to its specific receptor serum stimulation-2 (ST2). Depending on the tissue context, IL-33 performs multiple functions encompassing host defence, immune response, initiation and amplification of inflammation, tissue repair, and homeostasis. The levels and activity of IL-33 in the body are controlled by complex IL-33-targeting regulatory pathways. The unique temporal and spatial expression patterns of IL-33 are associated with host homeostasis and the development of immune and inflammatory disorders. Therefore, understanding the origin, function, and processes of IL-33 under various conditions is crucial. This review summarises the regulatory mechanisms underlying the IL-33/ST2 signalling axis and its potential role and clinical significance in immune and inflammatory diseases, and discusses the current complex and conflicting findings related to IL-33 in host responses.

Going Full TeRM: The Seminal Role of Tissue-Resident Macrophages in Organ Remodeling during Pregnancy and Lactation

During pregnancy and lactation, the uterus and mammary glands undergo remarkable structural changes to perform their critical reproductive functions before reverting to their original dormant state upon childbirth and weaning, respectively. Underlying this incredible plasticity are complex remodeling processes that rely on coordinated decisions at both the cellular and tissue-subunit levels. With their exceptional versatility, tissue-resident macrophages play a variety of supporting roles in these organs during each stage of development, ranging from maintaining immune homeostasis to facilitating tissue remodeling, although much remains to be discovered about the identity and regulation of individual macrophage subsets. In this study, we review the increasingly appreciated contributions of these immune cells to the reproductive process and speculate on future lines of inquiry. Deepening our understanding of their interactions with the parenchymal or stromal populations in their respective niches may reveal new strategies to ameliorate complications in pregnancy and breastfeeding, thereby improving maternal health and well-being.

Trophoblast-derived miR-410-5p induces M2 macrophage polarization and mediates immunotolerance at the fetal-maternal interface by targeting the STAT1 signaling pathway

BACKGROUND

Macrophages phenotypic deviation and immune imbalance play vital roles in pregnancy-associated diseases such as spontaneous miscarriage. Trophoblasts regulate phenotypic changes in macrophages, however, their underlying mechanism during pregnancy remains unclear. Therefore, this study aimed to elucidate the potential function of trophoblast-derived miRNAs (miR-410-5p) in macrophage polarization during pregnancy.

METHODS

Patient decidual macrophage tissue samples in spontaneous abortion group and normal pregnancy group (those who had induced abortion for non-medical reasons) were collected at the Reproductive Medicine Center of Renmin Hospital of Wuhan University from April to December 2021. Furthermore, placental villi and decidua tissue samples were collected from patients who had experienced a spontaneous miscarriage and normal pregnant women for validation and subsequent experiments at the Shenzhen Zhongshan Obstetrics & Gynecology Hospital (formerly Shenzhen Zhongshan Urology Hospital), from March 2021 to September 2022. As an animal model, 36 female mice were randomly divided into six groups as follows: naive-control, lipopolysaccharide-model, agomir-negative control prevention, agomir-410-5p prevention, agomir-negative control treatment, and agomir-410-5p treatment groups. We analyzed the miR-410-5p expression in abortion tissue and plasma samples; and supplemented miR-410-5p to evaluate embryonic absorption in vivo. The main source of miR-410-5p at the maternal-fetal interface was analyzed, and the possible target gene, signal transducer and activator of transcription (STAT) 1, of miR-410-5p was predicted. The effect of miR-410-5p and STAT1 regulation on macrophage phenotype, oxidative metabolism, and mitochondrial membrane potential was analyzed in vitro.

RESULTS

MiR-410-5p levels were lower in the spontaneous abortion group compared with the normal pregnancy group, and plasma miR-410-5p levels could predict pregnancy and spontaneous abortion. Prophylactic supplementation of miR-410-5p in pregnant mice reduced lipopolysaccharide-mediated embryonic absorption and downregulated the decidual macrophage pro-inflammatory phenotype. MiR-410-5p were mainly distributed in villi, and trophoblasts secreted exosomes-miR-410-5p at the maternal-fetal interface. After macrophages captured exosomes, the cells shifted to the tolerance phenotype. STAT1 was a potential target gene of miR-410-5p. MiR-410-5p bound to STAT1 mRNA, and inhibited the expression of STAT1 protein. STAT1 can drive macrophages to mature to a pro-inflammatory phenotype. MiR-410-5p competitive silencing of STAT1 can avoid macrophage immune disorders.

CONCLUSION

MiR-410-5p promotes M2 macrophage polarization by inhibiting STAT1, thus ensuring a healthy pregnancy. These findings are of great significance for diagnosing and preventing spontaneous miscarriage, providing a new perspective for further research in this field.

Inflammatory responses in early pregnancy: Physiological and pathological perspectives

Background

Several conditions such as infertility, repeated implantation failure, and recurrent pregnancy loss can pose challenges in early pregnancy. These issues can be caused by the abnormal inflammatory response with various factors, including exogenous and endogenous agents, and pathogenic and nonpathogenic agents. In addition, they can be exacerbated by maternal immune response to the abovementioned factors.

Methods

This review aimed to assess the detrimental inflammatory effects of chronic endometritis, endometrial microbiota disturbance, and maternal immune system abnormalities on early pregnancy. Further, essential details such as ovulation, implantation, trophoblast invasion, and placental formation, were examined, thereby highlighting the beneficial roles of inflammation.

Main Findings

Excessive inflammation was associated with various early pregnancy disorders. Meanwhile, a lack of appropriate inflammation could also contribute to the development of different early pregnancy complications.

Conclusion

Excessive inflammation and insufficient inflammation can possibly lead to abnormal conditions in early pregnancy, and appropriate inflammation is required for a successful pregnancy.

Endometrial TGFβ signaling fosters early pregnancy development by remodeling the fetomaternal interface

The endometrium is a unique and highly regenerative tissue with crucial roles during the reproductive lifespan of a woman. As the first site of contact between mother and embryo, the endometrium, and its critical processes of decidualization and immune cell recruitment, play a leading role in the establishment of pregnancy, embryonic development, and reproductive capacity. These integral processes are achieved by the concerted actions of steroid hormones and a myriad of growth factor signaling pathways. This review focuses on the roles of the transforming growth factor β (TGFβ) pathway in the endometrium during the earliest stages of pregnancy through the lens of immune cell regulation and function. We discuss how key ligands in the TGFβ family signal through downstream SMAD transcription factors and ultimately remodel the endometrium into a state suitable for embryo implantation and development. We also focus on the key roles of the TGFβ signaling pathway in recruiting uterine natural killer cells and their collective remodeling of the decidua and spiral arteries. By providing key details about immune cell populations and TGFβ signaling within the endometrium, it is our goal to shed light on the intricate remodeling that is required to achieve a successful pregnancy.

DHT and Insulin Upregulate Secretion of the Soluble Decoy Receptor of IL-33 From Decidualized Endometrial Stromal Cells

Interleukin 33 (IL-33) signaling regulates most of the key processes of pregnancy, including decidualization, trophoblast proliferation and invasion, vascular remodeling, and placental growth. Accordingly, dysregulation of IL-33, its membrane-bound receptor (ST2L, transducer of IL-33 signaling), and its soluble decoy receptor (sST2, inhibitor of IL-33 signaling) has been linked to a wide range of adverse pregnancy outcomes that are common in women with obesity and polycystic ovary syndrome, that is, conditions associated with hyperandrogenism, insulin resistance, and compensatory hyperinsulinemia. To reveal if androgens and insulin might modulate uteroplacental IL-33 signaling, we investigated the effect of dihydrotestosterone (DHT) and/or insulin on the expression of ST2L and sST2 (along with the activity of their promoter regions), IL-33 and sIL1RAP (heterodimerization partner of sST2), during in vitro decidualization of endometrial stromal cells from 9 healthy women. DHT and insulin markedly upregulated sST2 secretion, in addition to the upregulation of its messenger RNA (mRNA) expression, while the proximal ST2 promoter, from which the sST2 transcript originates, was upregulated by insulin, and in a synergistic manner by DHT and insulin combination treatment. On the other hand, sIL1RAP was slightly downregulated by insulin and IL-33 mRNA expression was not affected by any of the hormones, while ST2L mRNA expression and transcription from its promoter region (distal ST2 promoter) could not be detected or showed a negligibly low level. We hypothesize that high levels of androgens and insulin might lead to subfertility and pregnancy complications, at least partially, through the sST2-dependent downregulation of uteroplacental IL-33 signaling.

Interferon ɛ restricts Zika virus infection in the female reproductive tract

Interferon ɛ (IFNɛ) is a unique type I IFN that has been implicated in host defense against sexually transmitted infections. Zika virus (ZIKV), an emerging pathogen, can infect the female reproductive tract (FRT) and cause devastating diseases, particularly in pregnant women. How IFNɛ contributes to protection against ZIKV infection in vivo is unknown. In this study, we show that IFNɛ plays a critical role in host protection against vaginal ZIKV infection in mice. We found that IFNɛ was expressed not only by epithelial cells in the FRT but also by immune and stromal cells at baseline or after exposure to viruses or specific Toll-like receptor (TLR) agonists. IFNɛ-deficient mice exhibited abnormalities in the epithelial border and underlying tissue in the cervicovaginal tract, and these defects were associated with increased susceptibility to vaginal but not subcutaneous ZIKV infection. IFNɛ deficiency resulted in an increase in magnitude, duration, and depth of ZIKV infection in the FRT. Critically, intravaginal administration of recombinant IFNɛ protected Ifnɛ-/- mice and highly susceptible Ifnar1-/- mice against vaginal ZIKV infection, indicating that IFNɛ was sufficient to provide protection even in the absence of signals from other type I IFNs and in an IFNAR1-independent manner. Our findings reveal a potentially critical role for IFNɛ in mediating protection against the transmission of ZIKV in the context of sexual contact.

The NR2F2-HAND2 signaling axis regulates progesterone actions in the uterus at early pregnancy

Endometrial function is dependent on a tight crosstalk between the epithelial and stromal cells of the endometrium. This communication is critical to ensure a fertile uterus and relies on progesterone and estrogen signaling to prepare a receptive uterus for embryo implantation in early pregnancy. One of the key mediators of this crosstalk is the orphan nuclear receptor NR2F2, which regulates uterine epithelial receptivity and stromal cell differentiation. In order to determine the molecular mechanism regulated by NR2F2, RNAseq analysis was conducted on the uterus of PgrCre;Nr2f2f/f mice at Day 3.5 of pregnancy. This transcriptomic analysis demonstrated Nr2f2 ablation in Pgr-expressing cells leads to a reduction of Hand2 expression, increased levels of Hand2 downstream effectors Fgf1 and Fgf18, and a transcriptome manifesting suppressed progesterone signaling with an altered immune baseline. ChIPseq analysis conducted on the Day 3.5 pregnant mouse uterus for NR2F2 demonstrated the majority of NR2F2 occupies genomic regions that have H3K27ac and H3K4me1 histone modifications, including the loci of major uterine transcription regulators Hand2, Egr1, and Zbtb16. Furthermore, functional analysis of an NR2F2 occupying site that is conserved between human and mouse was capable to enhance endogenous HAND2 mRNA expression with the CRISPR activator in human endometrial stroma cells. These data establish the NR2F2 dependent regulation of Hand2 in the stroma and identify a cis-acting element for this action. In summary, our findings reveal a role of the NR2F2-HAND2 regulatory axis that determines the uterine transcriptomic pattern in preparation for the endometrial receptivity.

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.

Interferon ε restricts Zika virus infection in the female reproductive tract

Interferon ε (IFNε) is a unique type I IFN that has been implicated in host defense against sexually transmitted infections (STIs). Zika virus (ZIKV), an emerging pathogen, can infect the female reproductive tract (FRT) and cause devastating diseases, particularly in pregnant women. How IFNε contributes to protection against ZIKV infection in vivo is unknown. Here, we show that IFNε plays a critical role in host protection against vaginal ZIKV infection in mice. We found that IFNε was expressed not only by epithelial cells in the FRT, but also by certain immune and other cells at baseline or after exposure to viruses or specific TLR agonists. IFNε-deficient mice exhibited abnormalities in the epithelial border and underlying tissue in the cervicovaginal tract, and these defects were associated with increased susceptibility to vaginal, but not subcutaneous ZIKV infection. IFNε-deficiency resulted in an increase in magnitude, duration, and depth of ZIKV infection in the FRT. Critically, intravaginal administration of recombinant IFNε protected Ifnε-/- mice and highly susceptible Ifnar1-/- mice against vaginal ZIKV infection, indicating that IFNε was sufficient to provide protection even in the absence of signals from other type I IFNs and in an IFNAR1-independent manner. Our findings reveal a potentially critical role for IFNε in mediating protection against transmission of ZIKV in the context of sexual contact.

Circumvention of luteolysis reveals parturition pathways in mice dependent upon innate type 2 immunity

Although mice normally enter labor when their ovaries stop producing progesterone (luteolysis), parturition can also be triggered in this species through uterus-intrinsic pathways potentially analogous to the ones that trigger parturition in humans. Such pathways, however, remain largely undefined in both species. Here, we report that mice deficient in innate type 2 immunity experienced profound parturition delays when manipulated endocrinologically to circumvent luteolysis, thus obliging them to enter labor through uterus-intrinsic pathways. We found that these pathways were in part driven by the alarmin IL-33 produced by uterine interstitial fibroblasts. We also implicated important roles for uterine group 2 innate lymphoid cells, which demonstrated IL-33-dependent activation prior to labor onset, and eosinophils, which displayed evidence of elevated turnover in the prepartum uterus. These findings reveal a role for innate type 2 immunity in controlling the timing of labor onset through a cascade potentially relevant to human parturition.

Dysfunction of CCR1+ decidual macrophages is a potential risk factor in the occurrence of unexplained recurrent pregnancy loss

Recurrent pregnancy loss (RPL) puzzles 1-3% of women of childbearing age worldwide. Immunological factors account for more than 60% of cases of unexplained RPL (URPL); however, the underlying mechanism remains unclear. Here, using single-cell sequencing data and functional experiments with clinical samples, we identified a distinct population of CCR1⁺ decidual macrophages (dMφ) that were preferentially enriched in the decidua from normal early pregnancies but were substantially decreased in patients with URPL. Specific gene signatures endowed CCR1⁺ dMφ with immunosuppressive and migration-regulatory properties, which were attenuated in URPL. Additionally, CCR1⁺ dMφ promoted epithelial-to-mesenchymal transition (EMT) to promote trophoblast migration and invasion by activating the ERK1/2 signaling pathway. Decidual stromal cell (DSC)-derived CCL8 was the key regulator of CCR1⁺ dMφ as CCL8 recruited peripheral CCR1⁺ monocytes, induced a CCR1⁺ dMφ-like phenotype, and reinforced the CCR1⁺ dMφ-exerted modulation of trophoblasts. In patients with URPL, CCL8 expression in DSCs was decreased and trophoblast EMT was defective. Our findings revealed that CCR1⁺ dMφ play an important role in immune tolerance and trophoblast functions at the maternal-fetal interface. Additionally, decreased quantity and dysregulated function of CCR1⁺ dMφ result in URPL. In conclusion, we provide insights into the crosstalk between CCR1⁺ dMφ, trophoblasts, and DSCs at the maternal-fetal interface and macrophage-targeted interventions of URPL.