Whole-transcriptome sequencing identifies key mRNAs, miRNAs, lncRNAs, and circRNAs associated with unexplained recurrent pregnancy loss

CircPAPPA binds to PAPPA and promotes trophoblast proliferation in spontaneous abortion through the formation of circPAPPA-PAPPA complexes

BACKGROUND

Spontaneous abortion (SA) is one of the most common complications of early pregnancy. Circular RNAs play an important regulatory role in the development of pregnancy-associated diseases in females. While PAPPA is known to be lower in several problematic pregnancy conditions, the specific role it plays in spontaneous abortion has not yet been clearly defined.

METHODS

High-throughput sequencing and bioinformatics analysis were used to sort the circRNA expression profile in villus tissues from abortions that happened on their own. The presence and expression of circPAPPA in trophoblasts were detected by RNase-R digestion and RNA-FISH. The effect of circPAPPA on the proliferation of trophoblasts was evaluated by transfecting circRNA plasmids and siRNAs into the cells, followed by assessing the impact through the CCK-8 assay. Additionally, we investigated the localization and binding of circPAPPA and the PAPPA protein in trophoblasts through RNA FISH/IF, RIP and RNA pull-down assays.

RESULTS

We identified and characterized a new circRNA, circPAPPA, whose expression is down-regulated in villus tissues from spontaneous abortion. And high levels of circPAPPA lead to increased trophoblast proliferation in vitro. CircPAPPA can bind to PAPPA protein; mechanistically, the binding of PAPPA protein to circPAPPA significantly influences how circPAPPA regulates trophoblast activity.

CONCLUSIONS

Altogether, our study shows that circPAPPA binds to PAPPA, enhancing trophoblast proliferation in vitro, and suggests that targeting the circPAPPA-PAPPA interaction might be a novel therapeutic strategy for addressing spontaneous abortion.

Dysregulation of MYBL2 impairs extravillous trophoblast lineage development and function, contributing to recurrent spontaneous abortion

Recurrent spontaneous abortion (RSA) is a pregnancy-related condition characterized by a complex etiology. While placental trophoblast dysfunction is strongly associated with the development and progression of RSA, the underlying molecular mechanisms remain poorly understood. In this study, we observed a significant decrease in the expression of MYB Proto-Oncogene Like 2 (MYBL2) in the villous tissue of patients with RSA and the placentas of abortion-prone (AP) mice. Utilizing human trophoblast stem cells (hTSCs), we identified MYBL2 as a critical regulator of hTSCs stemness maintenance, promoting the expression of the stemness-associated genes Tumor protein p63 (TP63) and TEA Domain Transcription Factor 4 (TEAD4). Furthermore, MYBL2 facilitates the differentiation of hTSCs into extravillous trophoblast (EVT) by positively regulating Ajuba LIM Protein (AJUBA) expression. Using HTR-8/SVneo cell line, an immortalized EVT-like model, we found that MYBL2 positively regulates AJUBA expression by binding to the distal region of the AJUBA promoter. Additionally, the MYBL2-AJUBA axis enhances the migration and invasion of HTR-8/SVneo cells by suppressing the Hippo signaling pathway. Our study indicates that the dysregulation of MYBL2 expression in placental trophoblasts is associated with the pathogenesis of RSA, highlighting its potential as a therapeutic target for this condition.

Silencing circRNA-ZFAND6 induces trophoblast apoptosis by activating the mitochondrial pathway through the miR-575/SOD2 axis in unexplained recurrent spontaneous abortion

BACKGROUND

Unexplained recurrent spontaneous abortion (URSA) is a major problem in the field of human reproductive health. At present, several circRNAs have been reported to be differentially expressed and play an important biological function in pregnancy-related diseases. However, the role of circRNAs in URSA remains unclear.

METHODS

Levels of circRNA and miRNA were examined by RT-qPCR. The si-RNA and overexpression plasmid were respectively used to silence and overexpress circRNA-ZFAND6. We investigated the biological function of circRNA-ZFAND6 on trophoblasts through CCK8, EdU, Flow cytometric assay, Wound-healing assays and Transwell. Dual luciferase activity assay was conducted to identify the interaction between miR-575 and circRNA-ZFAND6.

RESULTS

We confirmed that circRNA-ZFAND6 was a stable circular RNA and was mostly localized in the cytoplasm. CircRNA-ZFAND6 was downregulated in placental villous tissues of URSA. CCK-8 and EdU assays showed that circRNA-ZFAND6 promoted the proliferation of HTR-8/SVneo cells. Flow cytometry and western blot assays prompted that circRNA-ZFAND6 obviously reduced cells apoptosis. Scratch wound healing and transwell assays revealed that circRNA-ZFAND6 had no effect on cell migration and invasion. CircRNA-ZFAND6 worked by adsorbing miR-575 through the ceRNA mechanism. MiR-575 can inhibit the proliferation and promote the apoptosis of HTR8/SVneo cells. SOD2 was identified as a direct target of miR-575 and was associated with mitochondrial apoptosis. Transmission electron microscopy, TMRM and ROS staining assays both suggested that circRNA-ZFAND6 affected mitochondrial apoptosis. Excessive trophoblast apoptosis was a key event to promote the development of URSA.

CONCLUSION

CircRNA-ZFAND6, which is low expressed in URSA and regulates the apoptosis of trophoblast cells, may affect the expression of SOD2 and thus affect mitochondrial apoptosis by regulating miR-575. This is closely related to the occurrence of URSA.

The circRNA Landscape in Recurrent Pregnacy Loss (RPL): A Comparison of Four Reproductive Tissues

Recurrent Pregnancy Loss (RPL), also named Recurrent Spontaneous Abortion (RSA), is a common fertility problem that refers to at least two consecutive pregnancy losses and affects 1-2% of couples all over the world. Despite common causes such as genetic abnormalities, uterine anomalies or hormonal and metabolic disorders, there is still a huge challenge in identifying the causes of about 40-60% of RPL patients. Circular RNAs (circRNAs) are endogenous ncRNAs with a unique closed-loop and single-stranded structure. Accumulated evidence indicates the role of circRNAs in embryonic development and implantation, which may help decipher the mechanisms and causes underlying RSA. Four works were selected in the SRA public repository that used RNAseq analysis in control and RPL samples in four tissues: endometrium, chorionic villus tissue, decidua and decidua immune cells. Two programs were selected for circRNA detection: DCC and CIRI2. A total of 1715 candidate circRNAs were detected after filtering the results. In the differential expression analysis, decidual tissue showed the highest percentage of circRNA with differential expression between cases and controls. CircRNAs originating from genes OGA, FNDC3B, RAB11FIP1, SIPA1L2 and GREB1L showed the highest expression in women suffering from pregnancy losses, in decidual tissue or endometrium. In the GO term enrichment analysis, multiple terms related to embryonic development and immunological response were consistently enriched in villus and decidual tissues. Although some differentially expressed circRNAs were shared between tissues, decidua seems the tissue of choice for analyzing the role of circRNAs in RPL.

Identification of risk loci for postpartum depression in a genome-wide association study

AIM

Genome-wide association studies (GWAS) of postpartum depression (PPD) based on accumulated cohorts with multiple ethnic backgrounds have failed to identify significantly associated loci. Herein, we conducted a GWAS of Japanese perinatal women along with detailed confounding information to uncover PPD-associated loci.

METHODS

The first and second cohorts (n = 9260 and n = 8582 perinatal women enrolled in the Tohoku Medical Megabank Project) and the third cohort (n = 997), recruited at Nagoya University, underwent genotyping. Of them, 1421, 1264, and 225 were classified as PPD based on the Edinburgh Postnatal Depression Scale 1 month after delivery. The most influential confounding factors of genetic liability to PPD were selected, and logistic regression analyses were performed to evaluate genetic associations with PPD after adjusting for confounders.

RESULTS

A meta-analysis of GWAS results from the three cohorts identified significant associations between PPD and the following loci (P < 5 × 10-8) by integrating the number of deliveries and the number of family members living together as the most influential confounders: rs377546683 at DAB1, rs11940752 near UGT8, rs141172317, rs117928019, rs76631412, rs118131805 at DOCK2, rs188907279 near ZNF572, rs504378, rs690150, rs491868, rs689917, rs474978, rs690118, rs690253 near DIRAS2, rs1435984417 at ZNF618, rs57705782 near PTPRM, and rs185293917 near PDGFB. Pathway analyses indicated that SNPs suggestively associated with PPD were mostly over-represented in categories including long-term depression, GnRH signaling, glutamatergic synapse, oxytocin signaling, and Rap1 signaling.

CONCLUSION

The current GWAS study identified eight loci significantly associated with PPD, which may clarify the genetic structure underlying its pathogenesis.

Hypermethylation and low expression of FOXM1 predisposes women to unexplained recurrent miscarriage by impairing trophoblast stem cell proliferation

Recurrent miscarriage (RM) is a distressing pregnancy complication with an unknown etiology. Increasing evidence indicates the relevance of dysregulation of human trophoblast stem cells (hTSCs), which may play a role in the development of RM. However, the potential molecular regulatory mechanism underlying the initiation and maintenance of hTSCs is yet to be fully elucidated. In this study, we performed data analysis and identified Forkhead box M1 (FOXM1) as a potential factor associated with RM. FOXM1 is a typical transcription factor known for its involvement in various pathophysiological processes, while the precise function of FOXM1 functions in hTSCs and RM remains incompletely understood. Utilizing RNA-seq, CUT&Tag, ChIP-qPCR, and sodium bisulfite conversion methods for methylation analysis, we elucidate the underlying regulatory mechanisms of FOXM1 in hTSCs and its implications in RM. Our findings demonstrate the relative high expression of FOXM1 in proliferating cytotrophoblasts (CTBs) compared to differentiated extravillous cytotrophoblasts (EVTs) and syncytiotrophoblasts (STBs). Besides, we provide evidence supporting a significant correlation between FOXM1 downregulation and the incidence of RM. Furthermore, we demonstrate the significant role of FOXM1 in regulating hTSCs proliferation and cell cycle through the transcriptional regulation of CDKN3, CCNB2, CCNA2, MAD2L1 and CDC25C. Notably, we observed a correlation between the downregulation of FOXM1 in RM and hypermethylation in its promoter region. Collectively, these results provide insights into the impact of FOXM1 on trophoblast regulation and offer a novel perspective on RM.

Identification of prognosis-related lncRNAs and cell validation in lung squamous cell carcinoma based on TCGA data

Objective

To discern long non-coding RNAs (lncRNAs) with prognostic relevance in the context of lung squamous cell carcinoma (LUSC), we intend to predict target genes by leveraging The Cancer Genome Atlas (TCGA) repository. Subsequently, we aim to investigate the proliferative potential of critical lncRNAs within the LUSC milieu.

Methods

DESeq2 was employed to identify differentially expressed genes within the TCGA database. Following this, we utilized both univariate and multivariate Cox regression analyses to identify lncRNAs with prognostic relevance. Noteworthy lncRNAs were selected for validation in cell lines. The intracellular localization of these lncRNAs was ascertained through nucleocytoplasmic isolation experiments. Additionally, the impact of these lncRNAs on cellular proliferation, invasion, and migration capabilities was investigated using an Antisense oligonucleotides (ASO) knockdown system.

Results

Multivariate Cox regression identified a total of 12 candidate genes, consisting of seven downregulated lncRNAs (BRE-AS1, CCL15-CCL14, DNMBP-AS1, LINC00482, LOC100129034, MIR22HG, PRR26) and five upregulated lncRNAs (FAM83A-AS1, LINC00628, LINC00923, LINC01341, LOC100130691). The target genes associated with these lncRNAs exhibit significant enrichment within diverse biological pathways, including metabolic processes, cancer pathways, MAPK signaling, PI3K-Akt signaling, protein binding, cellular components, cellular transformation, and other functional categories. Furthermore, nucleocytoplasmic fractionation experiments demonstrated that LINC00923 and LINC01341 are predominantly localized within the cellular nucleus. Subsequent investigations utilizing CCK-8 assays and colony formation assays revealed that the knockdown of LINC00923 and LINC01341 effectively suppressed the proliferation of H226 and H1703 cells. Additionally, transwell assays showed that knockdown of LINC00923 and LINC01341 significantly attenuated the invasive and migratory capacities of H226 and H1703 cells.

Conclusion

This study has identified 12 candidate lncRNA associated with prognostic implications, among which LINC00923 and LINC01341 exhibit potential as markers for the prediction of LUSC outcomes.

Emerging role of miRNAs, lncRNAs, and circRNAs in pregnancy-associated diseases

ABSTRACT

Accumulating studies have demonstrated that non-coding RNAs (ncRNAs), functioning as important regulators of transcription and translation, are involved in the establishment and maintenance of pregnancy, especially the maternal immune adaptation process. The endometrial stromal cells (ESCs), trophoblast cells, and decidua immune cells that reside at the maternal-fetal interface are thought to play significant roles in normal pregnancy and pregnancy-associated diseases. Here, we reviewed the up-to-date evidence on how microRNA, long non-coding RNA, and circular RNA regulate ESCs, trophoblast cells, and immune cells and discussed the potential applications of these ncRNAs as diagnostic and therapeutic markers in pregnancy complications.

Epigenetic and transcriptomic characterization of maternal-fetal interface in patients with recurrent miscarriage via an integrated multi-omics approach

Recurrent miscarriage (RM) occurs in 2.5 % of women aiming at childbirth, with unknown etiology in half of the cases. To identify the molecular features, an integrative study combining bioinformatics and multi-omics from GEO database was performed in these patients. Two datasets (GSE43256 and GSE73025) were integrated to indicate 1657 differentially expressed genes (DE-genes) in villus of females with RM. DE-genes in villus of females with RM mainly focused on cell growth and development. On the other hand, 230 DE-genes in decidua of RM patients were retrieved from GSE113790, and the DE-genes were involved in diverse functions, including transport of nutrients, immune response, extracellular matrix remodeling, and angiogenesis. Additionally, the results of immunologic signatures indicated that immune regulation played roles in both decidua and villus of RM. Interestingly, C1q and TNF related 7 (C1QTNF7), acquired from the intersection of decidua and villus datasets, is crucial in maintaining immune homeostasis, so is its upstream miRNA (miR-149-3p). The enhanced expression of C1QTNF7 in macrophages might inhibit the proliferation and migration of trophoblasts, and further result in pregnancy loss. The present study suggests C1QTNF7 might be a new target for the diagnosis and treatment of RM, but more basic researches are further required to illustrate its mechanism in RM.