Validation of mitochondrial biomarkers and immune dynamics in polycystic ovary syndrome.

PROBLEM: Polycystic ovary syndrome (PCOS), a prevalent endocrine-metabolic disorder, presents considerable therapeutic challenges due to its complex and elusive pathophysiology. METHOD OF STUDY: We employed three machine learning algorithms to identify potential biomarkers within a training dataset, comprising GSE138518, GSE155489, and GSE193123. The diagnostic accuracy of these biomarkers was rigorously evaluated using a validation dataset using area under the curve (AUC) metrics. Further validation in clinical samples was conducted using PCR and immunofluorescence techniques. Additionally, we investigate the complex interplay among immune cells in PCOS using CIBERSORT to uncover the relationships between the identified biomarkers and various immune cell types. RESULTS: Our analysis identified ACSS2, LPIN1, and NR4A1 as key mitochondria-related biomarkers associated with PCOS. A notable difference was observed in the immune microenvironment between PCOS patients and healthy controls. In particular, LPIN1 exhibited a positive correlation with resting mast cells, whereas NR4A1 demonstrated a negative correlation with monocytes in PCOS patients. CONCLUSION: ACSS2, LPIN1, and NR4A1 emerge as PCOS-related diagnostic biomarkers and potential intervention targets, opening new avenues for the diagnosis and management of PCOS.

Ginsenosides in endometrium-related diseases: Emerging roles and mechanisms.

Ginsenosides, agents extracted from an important herb (ginseng), are expected to provide new therapies for endometrium-related diseases. Based on the molecular types of ginsenosides, we reviewed the main pharmacological effects of ginsenosides against endometrium-related diseases (e.g., endometrial cancers, endometriosis, and endometritis). The mechanism of action of ginsenosides involves inducing apoptosis of endometrium-related cells, promoting autophagy of endometrium-related cells, regulating epithelial-mesenchymal transition (EMT) in endometrium-related cells, and activating the immune system to kill cells associated with endometrial diseases. We hope to provide a theoretical foundation for the treatment of endometrium-related diseases by ginsenosides.

Hypoxia-mediated chemotaxis and residence of macrophage in decidua by secreting VEGFA and CCL2 during normal pregnancy.

In brief: Hypoxia is vital for the establishment of the maternal-fetal interface during early pregnancy. This study shows that decidual macrophages (dMφ) could be recruited and reside in decidua under the regulation of hypoxia/VEGFA-CCL2 axis. Abstract: Infiltration and residence of decidual macrophages (dMφ) are of great significance to pregnancy maintenance for their role in angiogenesis, placental development, and inducing immune tolerance. Besides, hypoxia has now been acknowledged as an important biological event at maternal-fetal interface in the first trimester. However, whether and how hypoxia regulates biofunctions of dMφ remain elusive. Herein, we observed increased expression of C-C motif chemokine ligand 2 (CCL2) and residence of macrophages in decidua compared to secretory-phase endometrium. Moreover, hypoxia treatment on stromal cells improved the migration and adhesion of dMφ. Mechanistically, these effects might be mediated by upregulated CCL2 and adhesion molecules (especially ICAM2 and ICAM5) on stromal cells in the presence of endogenous vascular endothelial growth factor-A (VEGFA) in hypoxia. These findings were also verified by recombinant VEGFA and indirect coculture, indicating that the interaction between stromal cells and dMφ in hypoxia condition may facilitate dMφ recruitment and residence. In conclusion, VEGFA derived from a hypoxic environment may manipulate CCL2/CCR2 and adhesion molecules to enhance the interactions between dMφ and stromal cells and thus contribute to the enrichment of macrophages in decidua early during normal pregnancy.

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.

IL-27 promotes decidualization via the STAT3-ESR/PGR regulatory axis.

Appropriate decidualization is of great importance for embryo implantation, placental development and successful pregnancy. Although it has been well-acknowledged that decidualization relies on activation of progesterone-mediated signaling pathway, the exact mechanisms have not been elucidated. Here, we demonstrated that both IL-27 and IL27RA were highly expressed in decidua than those in endometrium during secretory phase. Estrogen plus progesterone significantly upregulated the expression of IL-27 and IL-27RA in endometrium stromal cells (ESCs). In addition, inhibiting IL-27 signaling with IL-27 neutralization antibody (anti-IL-27) suppressed the expression of decidualization-related molecules, receptors of estrogen (gene coded by ESR) and progesterone (PGR) induced by cAMP or estrogen plus progesterone. Similar results were obtained from Il27ra-/- (knockout of Il27ra) female mice. Moreover, knockout of Il27ra did not affect the estrus cycle and folliculogenesis in mice but reduced implantation rate with the impairing decidualization. Mechanistically, IL-27 upregulated the expression of ESR1, ESR2 and PGR in ESCs and DSCs, as well as the phosphorylation level of STAT3. In the presence of estrogen plus progesterone, treatment with ESCs with anti-IL-27 inhibited the activation of STAT3. Also, the expression of ESR, PGR was decreased in Il27ra-/- mice. In conclusion, these findings demonstrate that IL-27 upregulated by estrogen and progestogen promotes decidualization possibly through a STAT3-dominant pathway.

An imbalance of the IL-33/ST2-AXL-efferocytosis axis induces pregnancy loss through metabolic reprogramming of decidual macrophages.

During embryo implantation, apoptosis is inevitable. These apoptotic cells (ACs) are removed by efferocytosis, in which macrophages are filled with a metabolite load nearly equal to the phagocyte itself. A timely question pertains to the relationship between efferocytosis-related metabolism and the immune behavior of decidual macrophages (dMΦs) and its effect on pregnancy outcome. Here, we report positive feedback of IL-33/ST2-AXL-efferocytosis leading to pregnancy failure through metabolic reprogramming of dMΦs. We compared the serum levels of IL-33 and sST2, along with IL-33 and ST2, efferocytosis and metabolism of dMΦs, from patients with normal pregnancies and unexplained recurrent pregnancy loss (RPL). We revealed disruption of the IL-33/ST2 axis, increased apoptotic cells and elevated efferocytosis of dMΦs from patients with RPL. The dMΦs that engulfed many apoptotic cells secreted more sST2 and less TGF-ß, which polarized dMΦs toward the M1 phenotype. Moreover, the elevated sST2 biased the efferocytosis-related metabolism of RPL dMΦs toward oxidative phosphorylation and exacerbated the disruption of the IL-33/ST2 signaling pathway. Metabolic disorders also lead to dysfunction of efferocytosis, resulting in more uncleared apoptotic cells and secondary necrosis. We also screened the efferocytotic molecule AXL regulated by IL-33/ST2. This positive feedback axis of IL-33/ST2-AXL-efferocytosis led to pregnancy failure. IL-33 knockout mice demonstrated poor pregnancy outcomes, and exogenous supplementation with mouse IL-33 reduced the embryo losses. These findings highlight a new etiological mechanism whereby dMΦs leverage immunometabolism for homeostasis of the microenvironment at the maternal-fetal interface.

A positive COX-2/IL-1ß loop promotes decidualization by upregulating CD82.

A successful pregnancy requires sufficient decidualization of endometrial stromal cells (ESCs). CD82, a metastasis suppressor, is a critical regulator for trophoblast invasion but the effect in decidualization was largely unknown. Here we reported that there was a high level of CD82 in DSC by the immunohistochemistry staining and flow cytometer analysis. Stimulation with prostaglandin E2 (PGE2) elevated the expression of CD82 in ESCs. In contrast, celecoxib, a selective COX-2 inhibitor, significantly downregulated the expression of CD82 in decidual stromal cells (DSCs). Bioinformatics analysis and further research showed that recombinant human interleukin (IL)-1ß protein (rhIL-1ß) upregulated CD82 in ESCs. Of note, blocking IL-1ß signaling with anti-human IL-1ß neutralizing antibody could reverse the stimulatory effect of PGE2 on CD82 in ESCs. Silencing CD82 resulted in the decease of the decidualization markers PRL and IGFBP1 mRNA levels in DSCs. More importantly, we observed rhIL-1ß also upregulated the expression of COX-2, and the upregulation of PRL and IGFBP1 induced by rhIL-1ß could be abolished by celecoxib in ESCs or CD82 deficiency in DSCs. This study suggests that CD82 should be a novel promotor for decidualization under a positive regulation of the COX-2/PGE2/IL-1ß positive feedback loop.

Protopanaxadiol improves endometriosis associated infertility and miscarriage in sex hormones receptors-dependent and independent manners.

Background: Patients with endometriosis (EMs) have high risks of infertility and spontaneous abortion. How to remodel the fertility of patients with EMs has always been the hot spot and difficulty in the field of reproductive medicine. As an aglycone of ginsenosides, protopanaxadiol (PPD) possesses pleiotropic biological functions and has high medicinal values. We aimed to investigate the effect and potential mechanism of PPD in the treatment of EMs-associated infertility and spontaneous abortion. Methods: The EMs mice models were constructed by allotransplantation. The pregnancy rates, embryo implantation numbers and embryo resorption rates of control and EMs were counted. RNA sequencing, qRT-PCR, enzyme linked immunosorbent assay (ELISA) and FCM analysis were performed to screen and confirm the expression of endometrial receptivity/decidualization-related molecules, inflammation cytokines and NK cell function-related molecules in vitro and/or in vivo. The SWISS Target Prediction, STRING and Cytoscape were carried out to predict the potential cellular sensory proteins, the protein-protein interaction (PPI) network between sensory proteins and fertility-related molecules, respectively. Micro-CT detection, liver and kidney function tests were used to evaluate the safety. Results: Here, we observe that PPD significantly up-regulates endometrial receptivity-related molecules (e.g., Lif, Igfbp1, Mmps, collagens) and restricts pelvic inflammatory response (low levels of IL-12 and IFN-γ) of macrophage, and further remodel and improve the fertility of EMs mice. Additionally, PPD increases the expression of decidualization-related genes and Collagens, and promotes the proliferation, residence, immune tolerance and anagogic functions of decidual NK cells (low levels of CD16 and NKp30, high levels of Ki67, VEGF, TGF-ß) in pregnant EMs mice, and further triggers decidualization, decidual NK cell-mediated maternal-fetal immune tolerance and angiogenesis, preventing pregnant EMs mice from miscarriage. Mechanically, these effects should be dependent on ESRs, PGR and other sensory proteins (e.g., AR). Compared with GnRHa (the clinic first-line drug for EMs), PPD does not lead to the decline of serum estrogen and bone loss. Conclusion: These data suggest that PPD prevents EMs-associated infertility and miscarriage in sex hormones receptors-dependent and independent manners possibly, and provides a potential therapeutic strategy with high efficiency and low side effects to remodels the fertility of patients with EMs.

Ovarian hormones-autophagy-immunity axis in menstruation and endometriosis.

Menstruation occurs in few species and involves a cyclic process of proliferation, breakdown and regeneration under the control of ovarian hormones. Knowledge of normal endometrial physiology, as it pertains to the regulation of menstruation, is essential to understand disorders of menstruation. Accumulating evidence indicates that autophagy in the endometrium, under the regulation of ovarian hormones, can result in the infiltration of immune cells, which plays an indispensable role in the endometrium shedding, tissue repair and prevention of infections during menstruation. In addition, abnormal autophagy levels, together with resulting dysregulated immune system function, are associated with the pathogenesis and progression of endometriosis. Considering its potential value of autophagy as a target for the treatment of menstrual-related and endometrium-related disorders, we review the activity and function of autophagy during menstrual cycles. The role of the estrogen/progesterone-autophagy-immunity axis in endometriosis are also discussed.

WISP2/IGF1 promotes the survival of DSCs and impairs the cytotoxicity of decidual NK cells.

The survival and development of a semi-allogeneic fetus during pregnancy require the involvement of decidual stromal cells (DSCs), a series of cytokines and immune cells. Insulin-like growth factor 1 (IGF1) is a low molecular weight peptide hormone with similar metabolic activity and structural characteristics of proinsulin, which exerts its biological effects by binding with its receptor. Emerging evidence has shown that IGF1 is expressed at the maternal-fetal interface, but its special role in establishment and maintenance of pregnancy is largely unknown. Here, we found that the expression of IGF1 in the decidua was significantly higher than that in the endometrium. Additionally, decidua from women with normal pregnancy had high levels of IGF1 compared with that from women with unexplained recurrent spontaneous miscarriage. Estrogen and progesterone led to the increase of IGF1 in DSCs through upregulating the expression of WISP2. Recombinant IGF1 or DSCs-derived IGF1 increased the survival, reduced the apoptosis of DSCs, and downregulated the cytotoxicity of decidual NK cells (dNK) through interaction with IGF1R. These data suggest that estrogen and progesterone stimulate the growth of DSCs and impair the cytotoxicity of dNK possibly by the WISP2/IGF1 signaling pathway.

Changes in subsets of immunocytes in endometrial hyperplasia.

PROBLEM: Endometrial hyperplasia (EH) is characterized by an endometrial gland-to-stroma ratio >1 and is one of the most common gynecological diseases in the world. The role of immunocyte subsets in the development of EH remains unknown. METHODS: Patients who underwent dilatation and curettage due to abnormal uterine bleeding were recruited in the present study. Alterations in the numbers of different types of immune cell subsets in the endometrium of patients were analyzed by flow cytometry. RESULTS: The present study included 48 patients who were divided into three groups, based on the pathological results: (a) proliferative period (PP, n = 12); (b) simple EH (SEH, n = 30); and (c) complex EH (CEH, n = 6). The results showed that immune cell subpopulations were significantly different between these three groups. Compared with the PP group, the proportion of CD45+ cells and neutrophils and the subtypes of T cells and macrophages were significantly increased in the SEH patients. Compared with the PP and SEH groups, subsets of immunocytes in the CEH group were significantly decreased, including the population of CD45+ cells and the subtypes of T cells and natural killer cells; in contrast, the proportion of macrophages was significantly increased. There were no significant differences between the other cell subsets in each group. CONCLUSION: The changes in immune cell subsets may be closely associated with the progression of EH. Although the specific role of different immune cell subsets in the development of the diseases requires further study, the changes in the proportions of immune cell subsets should not be ignored.

Microbe-metabolite-host axis, two-way action in the pathogenesis and treatment of human autoimmunity.

The role of microorganism in human diseases cannot be ignored. These microorganisms have evolved together with humans and worked together with body's mechanism to maintain immune and metabolic function. Emerging evidence shows that gut microbe and their metabolites open up new doors for the study of human response mechanism. The complexity and interdependence of these microbe-metabolite-host interactions are rapidly being elucidated. There are various changes of microbial levels in models or in patients of various autoimmune diseases (AIDs). In addition, the relevant metabolites involved in mechanism mainly include short-chain fatty acids (SCFAs), bile acids (BAs), and polysaccharide A (PSA). Meanwhile, the interaction between microbes and host genes is also a factor that must be considered. It has been demonstrated that human microbes are involved in the development of a variety of AIDs, including organ-specific AIDs and systemic AIDs. At the same time, microbes or related products can be used to remodel body's response to alleviate or cure diseases. This review summarizes the latest research of microbes and their related metabolites in AIDs. More importantly, it highlights novel and potential therapeutics, including fecal microbial transplantation, probiotics, prebiotics, and synbiotics. Nonetheless, exact mechanisms still remain elusive, and future research will focus on finding a specific strain that can act as a biomarker of an autoimmune disease.