ENO1 promotes trophoblast invasion regulated by E2F8 in recurrent miscarriage.

Recurrent miscarriage (RM) is related to the dysfunction of extravillous trophoblast cells (EVTs), but the comprehensive mechanisms remain largely unexplored. We analyzed single-cell RNA sequencing (scRNA-seq), bulk RNA sequencing and microarray datasets obtained from Gene Expression Omnibus (GEO) database to explore the hub genes in the mechanisms of RM. We identified 1724 differentially expressed genes (DEGs) in EVTs from the RM, and they were all expressed along the trajectory of EVTs. These DEGs were associated with hypoxia and glucose metabolism. Single-cell Regulatory Network Inference and Clustering (SCENIC) analysis revealed that E2F transcription factor (E2F) 8 (E2F8) was a key transcription factor for these DEGs. And the expression of ENO1 can be positively regulated by E2F8 via RNA sequencing analysis. Subsequently, we performed immunofluorescence assay (IF), plasmid transfection, western blotting, chromatin immunoprecipitation (ChIP), real-time quantitative polymerase chain reaction (qRT-PCR), and transwell assays for validation experiments. We found that the expression of alpha-Enolase 1 (ENO1) was lower in the placentas of RM. Importantly, E2F8 can transcriptionally regulate the expression of ENO1 to promote the invasion of trophoblast cells by inhibiting secreted frizzled-related protein 1/4 (SFRP1/4) to activate Wnt signaling pathway. Our results suggest that ENO1 can promote trophoblast invasion via an E2F8-dependent manner, highlighting a potential novel target for the physiological mechanisms of RM.

Endometrial protein expression and phosphorylation landscape decipher aberrant insulin and mTOR signalling in patients with recurrent pregnancy loss.

RESEARCH QUESTION: What are the proteomic and phosphoproteomic differences between the endometrium of women with recurrent pregnancy loss (RPL) and the endometrium of healthy control women during the proliferative and secretory phases of the menstrual cycle? DESIGN: In total, 54 endometrial samples were collected during the proliferative and secretory phases from women with RPL (n = 28) and healthy controls (n = 26). Comprehensive proteomic and phosphoproteomic analyses were conducted using label-free liquid chromatography-tandem mass spectrometry (n = 44), and verified through Western blotting (n = 10). Three comparison groups were established: total RPL endometrium versus total control endometrium; RPL proliferative endometrium versus control proliferative endometrium; and RPL secretory endometrium versus control secretory endometrium. RESULTS: Differentially expressed proteins and differentially phosphorylated proteins were identified in the three comparison groups. Combining pathway enrichment, network analysis and soft clustering analysis, the insulin/cyclic nucleotide signalling pathway and AMPK/mTOR signalling pathway were identified as the major contributors to the aberration of RPL endometrium. Western blotting verified altered expression of four proteins: cAMP-dependent protein kinase type I-ß regulatory subunit, adenylate cyclase type 3, 5'-AMP-activated protein kinase catalytic subunit α-2 and phosphatidate phosphatase LPIN2. CONCLUSIONS: This exploratory study provides insights into the differentiated protein expression and phosphorylation profiles of the endometrium of women with RPL in both the proliferative and sectretory phases of the menstrual cycle. The results highlight potential proteins associated with the pathogenesis of RPL that may serve as potential indicators for RPL. The findings contribute to the identification of potential targets for RPL treatment as well as its pathogenesis.

Downregulation of FHL2 suppressed trophoblast migration, invasion and epithelial-mesenchymal transition in recurrent miscarriage.

RESEARCH QUESTION: Is four and a half LIM domain 2 (FHL2) involved in trophoblast migration, invasion and epithelial-mesenchymal transition (EMT) in recurrent miscarriage? DESIGN: Villus tissue was collected from 24 patients who had experienced recurrent miscarriage and 24 healthy controls. FHL2 mRNA and protein expression in villus specimens were observed by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Small interfering RNA and overexpression plasmid were used to change the FHL2 expression. JAR and HTR8/SVneo cell lines were used to conduct scratch-wound assay and transwell assay to detect trophoblast migration and invasion of FHL2. Downstream molecule expression of mRNA and protein and EMT markers were verified by qRT-PCR and Western blot. RESULTS: Significantly lower FHL2 mRNA (P = 0.019) and protein (P = 0.0014) expression was found in trophoblasts from the recurrent miscarriage group compared with healthy controls. FHL2 knockdown repressed migration (P = 0.0046), invasion (P < 0.001) and EMT, as shown by significant differences in mRNA and protein expression of the EMT markers N-cadherin, E-cadherin, Vimentin and Snail (all P < 0.05) of extravillus trophoblasts. FHL2 overexpression enhanced migration (P = 0.025), invasion (P < 0.001) and EMT of extravillus trophoblasts (all EMT markers P < 0.05). The positive upstream factor FHL2 in the extracellular signal-related kinase pathway induced JunD expression, thereby promoting trophoblast migration and invasion via matrix metalloproteinase 2. CONCLUSIONS: FHL2 is involved in a regulatory pathway of trophoblast migration, invasion and EMT during early pregnancy, and may have a role in recurrent miscarriage pathogenesis, which can serve as a possible target for novel therapeutic development.

Impaired decidualization and relative increase of PROK1 expression in the decidua of patients with unexplained recurrent pregnancy loss showing insulin resistance.

A recent meta-analysis revealed that patients with unexplained recurrent pregnancy loss (RPL) show higher insulin resistance compared to healthy controls. However, the etiology of RPL remains unknown. Prokineticin (PROK1), a pleiotropic uterine endometrial protein, is important for implantation and decidualization and is regulated by hypoxia and insulin. In this study, we investigated the decidualization status and the role of PROK1 in the decidua of patients with unexplained RPL showing insulin resistance. Thirty-two patients with unexplained RPL were included in this study. Following the diagnosis of a miscarriage, the decidua and villi of the patient were surgically collected. Fasting blood glucose and insulin levels were measured, and HOMA-ß was calculated. Using IHC and ELISA, the expression of IGFBP-1, PRL and PROK1 in the decidua and IGF-2 in the villi were analyzed in patients with euploid miscarriage with a high HOMA-ß index (n = 8) and compared to controls (euploid miscarriage with normal HOMA-ß: n = 12, aneuploid miscarriage with normal HOMA-ß: n = 12). The co-localization of PROK1 and IGFBP-1 was observed in the decidua by IHC. In the decidua of RPL patients with high HOMA-ß, the expression levels of IGFBP-1 and PRL were significantly lower, whereas the PROK1/IGFBP-1 ratio was significantly higher compared to that of the controls. IGF-2 expression in villi was significantly lower in RPL patients with high HOMA-ß. Impaired decidualization and excessive PROK1 production may have pathological implications in patients with unexplained RPL with insulin resistance, especially under the state of hyper insulin production.

miRNAs associated with endoplasmic reticulum stress and unfolded protein response during decidualization.

RESEARCH QUESTION: Do microRNAs (miRNAs) play a role in regulating endoplasmic reticulum stress (ERS) and unfolded protein response (UPR) in decidualized cells and endometrium associated with reproductive failures? DESIGN: Endometrial stromal cell line St-T1b was decidualized in vitro with 8-Br-cAMP over 5 days, or treated with the ERS inducer thapsigargin. Expression of ERS sensors, UPR markers and potential miRNA regulators was analysed by quantitative PCR. Endometrial biopsies from patients with recurrent pregnancy loss (RPL) and recurrent implantation failure (RIF) were investigated for the location of miRNA expression. RESULTS: Decidualization of St-T1b cells resulted in increased expression of ERS sensors including ATF6α, PERK and IRE1α, and the UPR marker, CHOP. TXNIP, which serves as a link between the ERS pathway and inflammation, as well as inflammasome NLRP3 and interleukin 1ß expression increased in decidualized cells. An in-silico analysis identified miR-17-5p, miR-21-5p and miR-193b-3p as miRNAs potentially involved in regulation of the ERS/UPR pathways and inflammation associated with embryo implantation. Their expression decreased significantly (P ≤ 0.0391) in non-decidualized cells in the presence of thapsigargin. Finally, expression of the selected miRNAs was localized by in-situ hybridization in stromal and glandular epithelial cells in endometrial samples from patients with RPL and RIF. Expression in stroma cells from patients with RPL was lower in comparison with stroma cells from patients with RIF. CONCLUSIONS: Decidualization in St-T1b cells is accompanied by ERS/UPR processes, associated with an inflammatory response that is potentially influenced by miR-17-5p, miR-21-5p and miR-193b-3p. These miRNAs are expressed differentially in stromal cells from patients with RPL and RIF, indicating an alteration in regulation of the ERS/UPR pathways.

Proteomic profiling analysis of human endometrium in women with unexplained recurrent spontaneous abortion.

Unexplained recurrent spontaneous abortion (URSA) seriously affects female reproductive health, causing a great burden to patients both physically and mentally. Endometrial decidualization plays an important role in pregnancy, and impaired decidualization is an essential cause of URSA, but the cause of the damage is still poorly understood. This study aimed to reveal the pathogenesis of URSA by analyzing the differential protein expression profiles in the decidual tissue of patients with recurrent abortion compared to those with normal pregnancy. Morphological analysis revealed abnormal decidualization of endometrial tissue in patients with URSA. Quantitative proteomics analysis showed that a total of 146 differentially expressed proteins were identified between the two groups, among which 95 proteins were downregulated and 51 proteins were upregulated. Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways revealed that the protein expression profile and signaling pathways of endometrium in patients with URSA changed significantly, and cytoskeleton remodeling and morphological transformation disorders were associated with abortion induced by incomplete decidualization. Meanwhile, transcription factors analysis showed that the 3 most affected families were zf-C2H2, MYB and HMG. Therefore, our study may provide a basis for searching for potential markers of decidualization injury. SIGNIFICANCE: At present, there are still about 50% of RSA patients with unknown causes, which brings great difficulties and blindness to clinical diagnosis and treatment.The limited proteomic studies on URSA further contribute to the lack of understanding in this field. However, in this study, the focus was on proteomic profiling analysis of the human endometrium in URSA patients compared to normal women. The findings revealed that cytoskeletal remodeling disorder is a significant contributor to the failure of decidualization in URSA patients. This insight highlights the potential role of cytoskeleton-related proteins in the pathogenesis of URSA, providing valuable information for further research and potential therapeutic interventions.

T cell immunity and the etiology and pathogenesis of preeclampsia.

Preeclampsia is more common in nulliparous women, their first pregnancies with a new partner in multiparous women, pregnant women with short duration of cohabitation, and in pregnancies with donor eggs, where the fetus is completely foreign to the mother. The epidemiological study findings strongly suggest that inadequate induction of tolerance to paternal/fetal antigens is involved in the pathogenesis of preeclampsia. This review proposes that preeclampsia may be caused by a reduction in paternal/fetal antigen-specific regulatory T (Treg) cells and decreased PD-1 expression on clonally expanded CD8+ effector memory T (TEM) cells, resulting in a breakdown of mother-to-fetus tolerance. The immune environment of preeclampsia is clearly different from that of recurrent pregnancy loss (RPL). In preeclampsia, cloned Treg cells decreases, and PD-1 expression on cloned CD8+TEM decreased. In RPL, the total number of Treg cells decreased, and the total number of clonally expanded CD8+TEM cells increases. In addition to these changes, increased differentiation of Th17 cells has also been observed in preeclampsia. This change is caused by soluble endoglin, that is increased in preeclampsia, neutralizing TGFß. These immunological changes make the fetus more susceptible to attacks from maternal T cells.

MITA Promotes Macrophage Proinflammatory Polarization and Its circRNA-Related Regulatory Mechanism in Recurrent Miscarriage.

MITA (also called STING), a master regulator of DNA-mediated innate immune activation, is a potential therapeutic target for viral infection and virus-related diseases. The circRNA-mediated ceRNA network plays important roles in gene regulation and may contribute to many human diseases. However, the relationship between MITA and recurrent miscarriage (RM) and its circRNA-related regulatory mechanisms remain unclear. In this study, we validated that the decidual M1/M2 ratio was upregulated in RM patients, suggesting the vital roles of decidual macrophages in the pathogenesis of RM. We found that MITA was highly expressed in decidual macrophages of RM patients and validated that MITA could promote apoptosis and macrophage proinflammatory polarization in THP-1-derived macrophage (TDM) cells. Using circRNA sequencing and bioinformatic analysis, we screened out a novel circRNA (circKIAA0391) that is overexpressed in decidual macrophages of RM patients. Mechanistically, we found that circKIAA0391 could promote the apoptosis and proinflammatory polarization of TDM cells by sponging the miR-512-5p/MITA axis. This study provides a theoretical basis for further understanding the impact of MITA on macrophages and its circRNA-related regulatory mechanisms, which may have a crucial immunomodulatory function in the pathophysiology of RM.

Immunohistochemical study of MMP-2, MMP-9, EGFR and IL-8 in decidual and trophoblastic specimens of recurrent pregnancy loss cases.

BACKGROUND AND AIM: Unexplained recurrent pregnancy loss has been a a challenging research task to experts since there is no explicit pathophysiological mechanism and therefore, the treatment remains elusive. Immunological imbalance and morphological abnormalities are under investigation. This study aims to evaluate the implication of MMP-2, MMP-9, EGFR, and IL-8 in recurrent pregnancy loss cases. MATERIALS & METHODS: The study was carried out through comparison among two groups; the unexplained miscarriage group which consisted of 22 women, and the control group consisted of 18 women, who had electively terminated their pregnancies. Both groups were in the first trimester of gestation. The specimens included the trophoblast, decidua basalis, and decidua parietalis. The study was conducted via immunohistochemical methods. Antibodies were used against MMP-2, MMP-9, EGFR, and IL-8. The results were presented at a contingency table and were statistically analyzed with the Chi-Square Test (X2). RESULTS: There were remarkable disparities in some cases in the comparison of the two groups. MMP-9 was detected significantly high in recurrent pregnancy loss (RPL) cases, both on trophoblastic and decidual specimens (p-value < .00001), MMP-2 displayed no difference among the two groups (mild to moderate detection on trophoblast and almost negative on decidual tissues). EGFR was highly detected in trophoblastic tissue (p-value = .014). IL-8 detection was particularly different in both trophoblast and decidua parietalis of the two groups (p-value < .01). CONCLUSION: The study revealed both morphological and immunological dysregulations that might participate in the RPL pathogenesis.

Endogenous retrotransposons cause catastrophic deoxyribonucleic acid damage in human trophoblasts.

OBJECTIVE: To determine the mechanistic role of mobile genetic elements in causing widespread DNA damage in primary human trophoblasts. DESIGN: Experimental ex vivo study. SETTING: Hospital-affiliated University. PATIENT(S): Trophoblasts from a patient with unexplained recurrent pregnancy loss and patients with spontaneous and elective abortions (n = 10). INTERVENTION(S): Biochemical and genetic analysis and modification of primary human trophoblasts. MAIN OUTCOME MEASURE(S): To phenotype and systematically evaluate the underlying pathogenic mechanism for elevated DNA damage observed in trophoblasts derived from a patient with unexplained recurrent pregnancy loss, transcervical embryoscopy, G-band karyotyping, RNA sequencing, quantitative polymerase chain reaction, immunoblotting, biochemical and siRNA assays, and whole-genome sequencing were performed. RESULT(S): Transcervical embryoscopy revealed a severely dysmorphic embryo that was euploid on G-band karyotyping. RNA sequencing was notable for markedly elevated LINE-1 expression, confirmed with quantitative polymerase chain reaction, and that resulted in elevated expression of LINE-1-encoded proteins, as shown by immunoblotting. Immunofluorescence, biochemical and genetic approaches demonstrated that overexpression of LINE-1 caused reversible widespread genomic damage and apoptosis. CONCLUSION(S): Derepression of LINE-1 elements in early trophoblasts results in reversible but widespread DNA damage.

Impact of regulatory T cell therapy on immune cell composition and fetal survival rate in abortion prone mice.

CONTEXT: Implantation of fertilised eggs and survival of a semi-allogenic embryo rely on the interactions between the cells and molecules preparing the uterus. We investigated the effect of regulatory T cell (Treg) therapy on the mechanism of local immune tolerance of mice prone to spontaneous abortion. METHODS: Naive T cells were stimulated in vitro with 17ß-oestradiol (E2), progesterone (P4) and TGF-ß1 for 96h to generate induced Tregs (iTreg). The iTregs were injected into DBA/2-mated pregnant CBA/J female mice (abortion prone model). On day 14 of pregnancy, mice were killed and decidual and placental tissues were collected for cellular composition analysis. RESULTS: Abortion prone mice (PBS treated) showed significantly lower survival rates (P <0.0001), increased CD3+ CD8+ (P <0.05), lower IDO+ (P <0.05) and increased natural killer cells (uNK) cell numbers (P <0.001) in the uterus, as well increased NK cells in the placenta (P <0.05) than in normal pregnant mice (CBA/J×BALB/c). Adoptive transfer of iTregs increased fetal survival in abortion-prone mice (P <0.01) and histopathological evaluation revealed a significantly decreased number of uNK cells in the uterus of TGF-ß1-, E2- and P4-iTregs (P<0.05, P<0.0001 and P<0.05, respectively) than in the PBS treated group. In the placenta, we found significantly lower numbers of uNK cells from TGF-ß1-, E2- and P4-iTregs than in the PBS treated group (P <0.05, P <0.05 and P <0.01, respectively). CONCLUSIONS: We propose that modulation of uterine NK cell activity through immunotherapy using Treg cells should be given more attention as an immunological strategy in the treatment of recurrent miscarriage.

Comprehensive RNA expression profile analysis of γδ T cells from peripheral blood and decidual tissues in normal pregnancy (NP) donors and patients with recurrent pregnancy loss (RPL).

Recurrent pregnancy loss (RPL) is a significant adverse pregnancy complication. The loss of immune tolerance has been proposed in the pathogenesis of RPL, however, the role of γδ T cells in RPL is still controversial. In this study, the gene expression patterns of circulated and decidual tissue-resident γδ T cells from normal pregnancy donors and patients with RPL were analyzed by SMART-seq. We demonstrate that the transcriptional expression profile of different subsets of γδ T cells in peripheral blood and decidual tissue is strikingly different. Vδ2 γδ T cells, as the major cytotoxic subset, are found to be enriched considerably, and the potential cytotoxicity of this subset is further enhanced in the decidua of RPL patients may be due to detrimental ROS reduction, enhanced metabolic activity, downregulation of immunosuppressive molecules expression in resident γδ T cells. Time-series Expression Miner (STEM) analysis of transcriptome indicates complex changes in gene expression in decidual γδ T cells over time from NP and RPL patients. Taken together, our work identifies high heterogeneity of gene signature in γδ T cells from NP and RPL patients between peripheral blood and decidua, which will be a useful resource for further studies of the critical roles of γδ T cells in RPL.

Age-related changes in CD4+ T and NK cell compartments may contribute to the occurrence of pregnancy loss in advanced maternal age.

A recent study characterized novel immune cell subsets (T, NK, and γδ T cell subsets) related to recurrent pregnancy loss (RPL). This study aims to assess whether these RPL-related immune cell subsets are affected by aging. The percentages of peripheral blood immunes cells from nulligravida women (NGW), women with a history of normal pregnancy (NP), and women with a history of pregnancy loss (PL) were detected by flow cytometry. The correlations between maternal age and cell percentages were assessed. We found a significant positive correlation between PL and maternal age. The percentages of effector memory CD4+ T (CD3+ CD4+ CD45RA¯ CCR7¯), terminally differentiated CD4+ T (CD3+ CD4+ CD45RA+ CCR7¯), and mature NK cells (CD3¯ CD56+lo) significantly increased with maternal age. A significant decrease in the percentage of Naïve CD4+ T cells (CD3+ CD4+ CD45RA+ CCR7+) with age was observed in women from the NP group. Women aged 35 or older had significantly higher percentages of effector memory CD4+ T cells, terminally differentiated CD4+ T cells, and mature NK cells than younger women. Maternal age positively correlates with terminally differentiated CD4+ T, effector memory CD4+ T, and mature NK cell percentages. In contrast, an inverse correlation was observed between Naïve CD4+ T cell and age among women from the NP group. Our findings indicate that age-related CD4+ T and NK cell dysregulation might be involved in the pathogenesis of PL in women with advanced maternal age. The underlying mechanism needs further investigation.

Clinical parameters associated with altered sperm DNA fragmentation index among primary infertile men: Findings from a real-life cross-sectional study.

BACKGROUND: Recurrent pregnancy loss and unexplained infertility are the current indications to test sperm DNA fragmentation according to the European Association of Urology Guidelines on sexual and reproductive health. OBJECTIVE: To identify a novel and better performing model to diagnose primary infertile men presenting with altered sperm DNA fragmentation and to outline its predictive ability in respect to current European Association of Urology Guidelines' recommendations. MATERIALS AND METHODS: Data from the latest 515 consecutive primary infertile men as for World Health Organization criteria were analyzed. Semen analysis, sperm DNA fragmentation (according to sperm chromatin structure assay), and serum hormones were considered in every patient. Altered sperm DNA fragmentation was defined with levels greater than 30%. Descriptive statistics was applied to compare patients with normal versus SDF > 30%. The new predicting model was identified through logistic regression analysis exploring potential predictors of SDF > 30% at first clinical presentation. Diagnostic accuracy between the two predictive models (European Association of Urology Guidelines vs. new) was assessed, and decision curve analyses tested their clinical benefit. RESULTS: Of 515, 268 (51.9%) patients had SDF > 30% at clinical presentation. Patients with SDF > 30% were older (median [interquartile range] 39 [35-43] vs. 37 [34-41] years), had lower mean testicular volume (Prader 15 [12-20] vs. 17.5 [13.5-20] and lower total motile sperm count (1.80 [0.7-13.2] vs. 11.82 [4.2-44.5] × 106 ), all p < 0.001. No other clinical differences were depicted. The two groups showed similar rates of history of recurrent pregnancy loss and unexplained infertility. At multivariable logistic regression analysis, age more than 38 years (odds ratio: 2.43) and baseline total motile sperm count less than 20 × 106 (odds ratio: 3.72) were associated with SDF > 30%, after adjusting for Prader < 15, history of miscarriages and unexplained infertility, all p < 0.0001. The newly identified model (unexplained infertility + history of poli-abortions + Prader < 15 + age ≥38 years + total motile sperm count <20 × 106 ) showed higher accuracy to identify SDF > 30% at baseline in respect to European Association of Urology Guidelines (area under the curve: 72.1 vs. 52.7), with superior clinical net benefit use. CONCLUSIONS: The application of the European Association of Urology sexual and reproductive health guidelines does not ensure proper identification of primary infertile men with pathological sperm DNA fragmentation. We propose a novel and better performing predictive model to identify the infertile men with altered sperm DNA fragmentation at first clinical assessment. DISCUSSION: As altered sperm DNA fragmentation has been widely linked with the inability to conceive, this second-level test could be further implemented over the diagnostic workup of a broader subset of patients presenting for male factor infertility. We propose a better performing model to identify this specific category of patients.

Sperm DNA fragmentation and idiopathic recurrent pregnancy loss: Results from a multicenter case-control study.

BACKGROUND: Sperm DNA fragmentation was hypothesized to have a role in the pathogenesis of recurrent pregnancy loss. Unfortunately, the quality of already published evidence is low. OBJECTIVES: To investigate the association between sperm DNA fragmentation and idiopathic recurrent pregnancy loss by limiting, as much as possible, the interference of confounding factors. MATERIALS AND METHODS: This was a retrospective multicenter case-control study conducted in two Italian University Hospitals (i.e., Policlinico Gemelli, Rome and Humanitas S. Pio X, Milan) from July 2020 to March 2022. Cases were men belonging to couples affected by first trimester idiopathic recurrent pregnancy loss, defined as the previous loss of two or more pregnancies. Two control groups were selected: (i) men belonging to couples with proven fertility (i.e., at least two previous full-term pregnancies) (control group A); (ii) men belonging to couples with proven infertility (i.e., the failure to achieve a pregnancy after 12 months or more of regular unprotected sexual intercourse) (control group B). The sperm DNA fragmentation index was measured by the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. RESULTS: We included 74 cases, 37 men with proven fertility (control group A) and 100 men belonging to infertile couples (control group B). The median sperm DNA fragmentation index was significantly lower in control group A (17%, interquartile range: 14.3%-20.6%) compared to both case group (24.5%, interquartile range: 17%-32%; p < 0.0001) and control group B (24%, interquartile range: 18.9%-30%; p = 0.001). The rate of subjects with sperm DNA fragmentation index greater than 30% was significantly higher in both case groups (28%, 95% confidence interval [18%-40%]) and control group B (26%, 95% confidence interval [18%, 36%]) compared to control group A (0%, 95% confidence interval [0%-10%]) (p < 0.001). Multivariate regression models yielded a significant association between sperm DNA fragmentation index and recurrent pregnancy loss (adjusted odds ratio 1.13, 95% confidence interval [1.04-1.23], p = 0.006), but failed to show an association between sperm DNA fragmentation index and infertility (adjusted odds ratio 1.13, 95% CI [1-1.29], p = 0.05). CONCLUSIONS: Men within couples affected by recurrent pregnancy loss or infertility had a significantly higher rate of sperm DNA fragmentation compared to fertile controls. However, after adjusting for covariates, sperm DNA fragmentation index was associated only with recurrent pregnancy loss.

TNFα/TNFR1 signal induces excessive senescence of decidua stromal cells in recurrent pregnancy loss.

Defects in decidual response are associated with adverse pregnancy outcomes which includes recurrent pregnancy loss (RPL). It is reported that cellular senescence happens during decidualization and pro-senescent decidual response in the luteal phase endometrium is related to RPL. However, the underlying mechanisms of how excessive decidual senescence takes place in RPL decidua cells remain largely unexplored. The senescent phenotype of RPL decidua and tumor necrosis factor receptor 1(TNFR1) expression were analyzed by using our previously published single-cell sequencing dataset of decidua cells from 6 RPL and 5 matched normal decidua, which were further verified by PCR and WB in decidual tissues. Effects of TNFα on the decidual stromal cells (DSCs) senescence and underlying molecular pathways were analyzed using the in vitro decidualization model of human endometrial stromal cells (HESCs). We showed that decidual stroma cells from RPL patients exhibited transcriptomic features of cellular senescence by analysis of single-cell datasets. The TNFα level and TNFR1 expression were increased in RPL decidua tissues. Furthermore, in vitro cell model demonstrated that increased TNFα induced excessive senescence during decidualization and TNFR1/p53/p16 pathway mediates TNFα-induced stromal senescence. In addition, we also found that the expression of IGFBP1 was regulated by TNFα-TNFR1 interaction during decidualization. Taken together, the present findings suggest that the increased secretion of TNFα induced stromal cell excessive senescence in RPL decidua, which is mediated via TNFR1, and thus provide a possible therapeutic target for the treatment of RPL.

Decreased expression and DNA hypermethylation of syncytin-1 in human villus tissues with unexplained recurrent spontaneous abortion.

Recurrent spontaneous abortion (RSA) affects approximately 5 % of women of reproductive age worldwide. The etiology and pathogenesis of approximately 50 % of RSA cases currently remain unclear, which known as unexplained RSA (URSA). Syncytin-1, an envelope protein encoded by HERV-W gene, is essential for human embryonic development. The purpose of this study was to explore the correlation between syncytin-1 expression and URSA occurrence. The villi tissues of URSA patients and patients with voluntary termination of pregnancy for non-medical reasons in early pregnancy (Control group) were collected. Compared with the Control group, syncytin-1 was abnormally low expressed in URSA villus tissues, and the HERV-W gene promoter was hypermethylated. Compared with the control group, the global DNA methylation level and the expression level of DNA methylases in the villus tissues of the URSA group had no significant difference. In addition, compared with the Control group, URSA villus tissue showed obviously abnormal apoptosis. Overexpression of syncytin-1 promoted the proliferation of HTR-8 cells and inhibited their apoptosis; while knockdown of syncytin-1 inhibited cell proliferation and promoted cell apoptosis. URSA villus tissue exhibited hypermethylation of the HERV-W gene and down-regulation of syncytin-1 expression. Syncytin-1 has the potential to be a predictive and diagnostic biomarker for URSA.

YY1/ITGA3 pathway may affect trophoblastic cells migration and invasion ability.

Recurrent spontaneous abortion (RSA) is a disturbing pregnancy disorder experienced by ~2.5% of women attempting to conceive. The pathogenesis of RSA is still unclear. Previous findings revealed that transcription factor YIN-YANG 1(YY1) was related to the pathogenesis of RSA by influence trophoblastic cell invasion ability. Present study aimed to investigate more specific molecular mechanism of YY1 playing in trophoblastic cells. In our research, RNA-seq and Chip-seq were used to find significant changed genes between si-YY1(Knock down of YY1) HTR-8/SVneo cells(n = 3) and HTR-8/SVneo cells(n = 3). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis results suggested that Integrins related pathway maybe necessary to biological functions of trophoblastic cells. Chip-seq dataset analysis results predict YY1 can regulate ITGA3/7 expression by binding to the promoter region of ITGA3/7. Furthermore, results from chip experiment, RT-PCR, Dual-luciferase reporter gene assay showed that YY1 was able to bind to the promoter region of ITGA3 and regulate ITGA3 mRNA and protein expression. However, ITGA7 could not be significant influenced by YY1. Besides, gene silencing experiment, Western blot and Immunofluorescence assay confirmed that both YY1 and ITGA3 can accelerate phosphorylation focal adhesion kinase and affect cytoskeleton formation in HTR-8/SVneo cells. In conclusion, YY1/ITGA3 play a critical role in trophoblast invasion ability by regulating cytoskeleton formation.

The miR-410-5p /ITGA6 axis participates in the pathogenesis of recurrent abortion by regulating the biological function of trophoblast.

The purpose of this study was to determine the regulation of the miR-410-5p /ITGA6 axis on the biological functions of trophoblast cells and the mechanism involved in recurrent spontaneous abortion（RSA）. We used qRT-PCR and Western blotting to quantify the expression levels of Mir-410-5p and ITGA6 in placenta of RSA and normal, and found that compared with normal placenta, the placenta of RSA patients showed higher miR-410-5p and lower ITGA6 expression. Dual luciferase reporter gene assay confirmed the binding of miR-410-5p to ITGA6. The expression of miR-410-5p and ITGA6, and proliferation, apoptosis, invasion and migration of trophoblast cells and the effect on the polarization of M2 macrophages were detected in the trophoblast derived cell lines HTR8/Svneo transfected with miR-410-5p mimic, sh-miR-410-5p and si-ITGA6 respectively. Meanwhile, the molecular mechanism of ITGA6 regulation on trophoblast cells was explored. Transfection with miR-410-5p mimic or si-ITGA6 attenuated the proliferation, migration and invasion and induced apoptosis of HTR-8/SVneo cells. Transfection of sh-miR-410-5p promoted proliferation, migration and invasion, and weakened apoptosis of HTR-8/SVneo cells. In addition, overexpression of miR-410-5p in trophoblast cells inhibited the polarization of M2 macrophages, while knockdown of miR-410-5p was beneficial to recruitment of trophoblast cell and promoted the polarization of M2 macrophages. ITGA6 may affect the biological functions of trophoblast cells by regulating PI3K/AKT and MAPK signaling pathways. In conclusion, miR-410-5p mediates trophoblast cell proliferation, apoptosis, invasion and migration through regulating ITGA6 expression.

Chronic Inflammatory Placental Disorders Associated With Recurrent Adverse Pregnancy Outcome.

Chronic inflammatory placental disorders are a group of rare but devastating gestational syndromes associated with adverse pregnancy outcome. This review focuses on three related conditions: villitis of unknown etiology (VUE), chronic histiocytic intervillositis (CHI) and massive perivillous fibrin deposition (MPFD). The hallmark of these disorders is infiltration of the placental architecture by maternal immune cells and disruption of the intervillous space, where gas exchange between the mother and fetus occurs. Currently, they can only be detected through histopathological examination of the placenta after a pregnancy has ended. All three are associated with a significant risk of recurrence in subsequent pregnancies. Villitis of unknown etiology is characterised by a destructive infiltrate of maternal CD8+ T lymphocytes invading into the chorionic villi, combined with activation of fetal villous macrophages. The diagnosis can only be made when an infectious aetiology has been excluded. VUE becomes more common as pregnancy progresses and is frequently seen with normal pregnancy outcome. However, severe early-onset villitis is usually associated with fetal growth restriction and recurrent pregnancy loss. Chronic histiocytic intervillositis is characterised by excessive accumulation of maternal CD68+ histiocytes in the intervillous space. It is associated with a wide spectrum of adverse pregnancy outcomes including high rates of first-trimester miscarriage, severe fetal growth restriction and late intrauterine fetal death. Intervillous histiocytes can also accumulate due to infection, including SARS-CoV-2, although this infection-induced intervillositis does not appear to recur. As with VUE, the diagnosis of CHI requires exclusion of an infectious cause. Women with recurrent CHI and their families are predisposed to autoimmune diseases, suggesting CHI may have an alloimmune pathology. This observation has driven attempts to prevent CHI with a wide range of maternal immunosuppression. Massive perivillous fibrin deposition is diagnosed when >25% of the intervillous space is occupied by fibrin, and is associated with fetal growth restriction and late intrauterine fetal death. Although not an inflammatory disorder per se, MPFD is frequently seen in association with both VUE and CHI. This review summarises current understanding of the prevalence, diagnostic features, clinical consequences, immune pathology and potential prophylaxis against recurrence in these three chronic inflammatory placental syndromes.