Decreased circUBAP2 Expression Is Associated with Preeclampsia by Limiting Trophoblast Cell Proliferation and Migration

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.

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.

CircHIRA sponges miR-196b-5p to promote porcine early embryonic development

Circular RNA (circRNA) is abundantly expressed in preimplantation embryos and embryonic stem cells in mice and humans. However, its function and mechanism in early development of mammalian embryos remain unclear. Here, we showed that circHIRA mediated miR-196b-5p to regulate porcine early embryonic development. We verified the circular feature of circHIRA by sanger sequencing, and proved the authenticity of circHIRA by enzyme digestion test. HIRA and circHIRA were expressed in porcine early embryos, and its expression levels significantly increased from 8-cell stage onwards and reached the maximum at the blastocyst stage. Functional studies revealed that circHIRA knockdown not only significantly reduced the developmental efficiency of embryos from 8-cell stage to blastocyst stage, but also impaired the blastocyst quality. Mechanistically, integrated analysis of miRNA prediction and gene expression showed that circHIRA knockdown significantly increased the expression of miR-196b-5p in porcine early embryos. Furthermore, miR-196b-5p inhibitor injection could rescue the early development of circHIRA knockdown embryos. Taken together, the findings reveal that circHIRA regulates porcine early embryonic development via inhibiting the expression of miR-196b-5p.

Current understanding of circular RNAs in preeclampsia

Preeclampsia (PE) is a multiple organ and system disease that seriously threatens the safety of the mother and infant during pregnancy, and has a profound impact on the morbidity and mortality of the mother and new babies. Presently, there are no remedies for cure of PE as to the mechanisms of PE are still unclear, and the only way to eliminate the symptoms is to deliver the placenta. Thus, new therapeutic targets for PE are urgently needed. Approximately 95% of human transcripts are thought to be non-coding RNAs, and the roles of them are to be increasingly recognized of great importance in various biological processes. Circular RNAs (circRNAs) are a class of non-coding RNAs, with no 5' caps and 3' polyadenylated tails, commonly produced by back-splicing of exons. The structure of circRNAs makes them more stable than their counterparts. Increasing evidence shows that circRNAs are involved in the pathogenesis of PE, but the biogenesis, functions, and mechanisms of circRNAs in PE are poorly understood. In the present review, we mainly summarize the biogenesis, functions, and possible mechanisms of circRNAs in the development and progression of PE, as well as opportunities and challenges in the treatment and prevention of PE.

Circ_0003945: an emerging biomarker and therapeutic target for human diseases

Due to the rapid development of RNA sequencing techniques, a circular non-coding RNA (ncRNA) known as circular RNAs (circRNAs) has gradually come into focus. As a distinguished member of the circRNA family, circ_0003945 has garnered attention for its aberrant expression and biochemical functions in human diseases. Subsequent studies have revealed that circ_0003945 could regulate tumor cells proliferation, migration, invasion, apoptosis, autophagy, angiogenesis, drug resistance, and radio resistance through the molecular mechanism of competitive endogenous RNA (ceRNA) during tumorigenesis. The expression of circ_0003945 is frequently associated with some clinical parameters and implies a poorer prognosis in the majority of cancers. In non-malignant conditions, circ_0003945 also holds considerable importance in diseases pathogenesis. This review aims to recapitulate molecular mechanism of circ_0003945 and elucidates its potential as a diagnostic and therapeutic target in neoplasms and other diseases.

Exploration of adverse events associated with risdiplam use: Retrospective cases from the US Food and Drug Administration Adverse Event Reporting System (FAERS) database

Risdiplam is a new drug for treating spinal muscular atrophy (SMA). However, pharmacovigilance analyses are necessary to objectively evaluate its safety-a crucial step in preventing severe adverse events (AEs). Accordingly, the primary objective of the current study was to examine the AEs associated with risdiplam use based on real-world data obtained from the US Food and Drug Administration Adverse Event Reporting System (FAERS) database. More specifically, we examined incidents reported between the third quarter of 2020 and the second quarter of 2023. The imbalance of risdiplam-related AEs was evaluated by computing the reporting odds ratio. A total of 5,406,334 reports were thoroughly reviewed. By removing duplicate reports, we identified 1588 reports in which risdiplam was the main suspected drug whose use was accompanied by 3470 associated AEs. Among the included AEs, 703 were categorized as serious and 885 as non-serious. Risdiplam use induced AEs across 18 organ systems, resulting in 130 positive signals. Notably, we detected new AE signals, including cardiac arrest, nephrolithiasis, tachycardia, loss of libido, and elevated hepatic enzyme activities; however, no ophthalmologic toxicity was reported. Although these new adverse reaction signals associated with risdiplam have been defined, long-term clinical studies are needed to confirm these findings. Nevertheless, our findings provide a valuable reference for improving the clinical management of SMA.

The role of circular RNA in preeclampsia: From pathophysiological mechanism to clinical application

Preeclampsia (PE) is a common pregnancy-induced hypertension disorder that poses a significant threat to the health of pregnant women and fetuses, and has become a leading cause of maternal, fetal, and neonatal mortality. Currently, the therapy strategy for PE is mainly prevention management and symptomatic treatment, and only delivery can completely terminate PE. Therefore, a deeper understanding of the pathogenesis of PE is needed to make treatment and prevention more effective and targeted. With the deepening of molecular etiology research, circular RNAs (circRNAs) have been found to be widely involved in various processes of PE pathogenesis. As a kind of RNA with a special "head to tail" loop structure, the characteristics of circRNAs enable them to play diverse roles in the pathophysiology of PE, and can also serve as ideal biomarkers for early prediction and monitoring progression of PE. In this review, we summarized the latest research on PE-related circRNAs, trying to elucidate the unique or shared roles of circRNAs in various pathophysiological mechanisms of PE, aiming to provide a whole picture of current research on PE-related circRNAs, and extend a new perspective for the precise screening and targeted therapy of PE.

Unveiling the prominent roles of circular RNAs ubiquitin binding associated protein 2 in cancers

Circular RNAs (circRNAs), a novel type of covalently closed non-coding RNAs, are widely expressed in eukaryotes and viruses. Accumulating evidence has shown that circRNAs play key roles in the pathophysiological changes process of human diseases and can affect cancer development and progression through regulating target genes expression, linear RNA transcription and protein generation. Recent studies had found that circRNA-UBAP2 (ubiquitin binding associated protein 2) was aberrantly expressed in various human tumors and could affect tumor cells proliferation, migration, invasion, cell cycle, anti-apoptosis, radioresistance, chemoresistance and other malignant biological behavioral progress. Mechanistic studies further revealed that circUBAP2 could affect the occurrence and development of human tumors through multiple different molecular regulatory pathways in vivo and in vitro. In addition, the abnormal expression of circUBAP2 was significantly correlated with the clinicopathological characteristics of malignant tumors and had potential value as biomarkers for the diagnosis and prognosis evaluation of cancer patients, which deserved further study. This review had summarized and discussed the oncogenic roles and clinical performances of circUBAP2 in various human malignancies with a focus on biological functions and molecular mechanisms, which could help to elevate the understanding to the roles of circRNAs and continue subsequent studies on circUBAP2.

The Critical Roles of Circular RNAs in Basic Research and Clinical Application of Female Reproductive-Related Diseases

Circular RNAs (circRNAs), produced by precursor mRNAs, are a type of covalently closed circular molecule without 5' caps and 3' polyadenylated tails. Recently, advances in high-throughput sequencing, transcriptomics and bioinformatics, have revealed that circRNAs with specific traits in tissue or cells play emerging roles in both physiological and panthological contexts instead of as simple by-products of transcription. However, bringing circRNAs to the forefront of clinical practice is still a long way off. In this review, we highlight the progress in the formation and function of circRNAs, and how circRNAs work in female reproductive-related diseases, such as recurrent spontaneous abortion, preeclampsia, and endometriosis. We also discussed the clinical potential of circRNAs as biomarkers, and therapeutic agents in female reproductive diseases as well as research controversies, technical issues, and biological knowledge gaps that need to be addressed. This review may instruct future basic research and clinical applications on circRNAs, especially in female reproduction.

MiR-30a-3p Targeting FLT1 Modulates Trophoblast Cell Proliferation in the Pathogenesis of Preeclampsia

Preeclampsia (PE) may pose significant adverse effects on pregnant women. Dysregulation of angiogenesis, trophoblast invasion, and proliferation are known to be associated with PE development and progression. Fms related tyrosine kinase 1 (FLT1), an anti-angiogenic factor, is consistently upregulated in PE patients. Recent papers highlight that aberrant miR-30a-3p expression contributes to PE development. More effects are needed to assess the biological function of placental miR-30a-3p in PE. The soluble FLT1 (sFLT1) and FLT1 levels were tested by ELISA assay and Western blotting assay. mRNA levels were measured by RT-qPCR assay. Colony formation and MTT assays were applied to assess the effect of miR-30a-3p on trophoblast cell proliferation. The serum sFLT1 and placental FLT1 levels were substantially high in patients with PE. Using miRNA microarray assay, we identified miR-30a-3p upregulation in PE patients' placenta tissues. We further confirmed that miR-30a-3p binds to the 3'-UTR of FLT1 gene and positively regulate its expression. Forcing miR-30a-3p expression inhibited trophoblast cell proliferation and vice versa. In conclusion, persistent high levels of FLT1 and miR-30a-3p may pose adverse effects on angiogenesis and trophoblast proliferation in placenta of PE patients. Therefore, targeting FLT1 and miR-30a-3p may serve as ideal strategies for managing patients with PE.

Regulatory roles of non-coding RNAs and m6A modification in trophoblast functions and the occurrence of its related adverse pregnancy outcomes

Adverse pregnancy outcomes, such as preeclampsia, gestational diabetes mellitus, fetal growth restriction, and recurrent miscarriage, occur frequently in pregnant women and might further induce morbidity and mortality for both mother and fetus. Increasing studies have shown that dysfunctions of human trophoblast are related to these adverse pregnancy outcomes. Recent studies also showed that environmental toxicants could induce trophoblast dysfunctions. Moreover, non-coding RNAs (ncRNAs) have been reported to play important regulatory roles in various cellular processes. However, the roles of ncRNAs in the regulation of trophoblast dysfunctions and the occurrence of adverse pregnancy outcomes still need to be further investigated, especially with exposure to environmental toxicants. In this review, we analyzed the regulatory mechanisms of ncRNAs and m6A methylation modification in the dysfunctions of trophoblast cells and the occurrence of adverse pregnancy outcomes and also summarized the harmful effects of environmental toxicants. In addition to DNA replication, mRNA transcription, and protein translation, ncRNAs and m6A modification might be considered as the fourth and fifth elements that regulate the genetic central dogma, respectively. Environmental toxicants might also affect these processes. In this review, we expect to provide a deeper scientific understanding of the occurrence of adverse pregnancy outcomes and to discover potential biomarkers for the diagnosis and treatment of these outcomes.

Circular RNAs in Pregnancy and the Placenta

The emerging field of circular RNAs (circRNAs) has identified their novel roles in the development and function of many cancers and inspired the interest of many researchers. circRNAs are also found throughout the healthy body, as well as in other pathological states, but while research into the function and abundance of circRNAs has progressed, our overall understanding of these molecules remains primitive. Importantly, recent studies are elucidating new roles for circRNAs in pregnancy, particularly in the placenta. Given that many of the genes responsible for circRNA production in cancer are also highly expressed in the placenta, it is likely that the same genes act in the production of circRNAs in the placenta. Furthermore, placental development can be referred to as ‘controlled cancer’, as it shares many key signalling pathways and hallmarks with tumour growth and metastasis. Hence, the roles of circRNAs in this field are important to study with respect to pregnancy success but also may provide novel insights for cancer progression. This review illuminates the known roles of circRNAs in pregnancy and the placenta, as well as demonstrating differential placental expressions of circRNAs between complicated and uncomplicated pregnancies.

The circular RNA circ_0099630/miR-940/receptor-associated factor 6 regulation cascade modulates the pathogenesis of periodontitis

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Circular RNA UBAP2 facilitates the cisplatin resistance of triple-negative breast cancer via microRNA-300/anti-silencing function 1B histone chaperone/PI3K/AKT/mTOR axis

Circular RNAs (CircRNAs) have attracted increasing attention in the diagnosis and treatment of human cancers. CircUBAP2 has been identified to promote the progression of triple-negative breast cancer (TNBC), but the function of circUBAP2 in the cisplatin (DDP) resistance of TNBC remains obscure. Our investigation showed that circUBAP2 was significantly upregulated in DDP-resistant TNBC and TNBC sensitivity to DDP could be enhanced by silencing of circUBAP2. Moreover, circUBAP2 was revealed to be a ceRNA for miR-300 to upregulate the expression of anti-silencing function 1B histone chaperone (ASF1B). The effect of circUBAP2/miR-300/ASF1B axis on DDP resistance of TNBC was evaluated by rescue experiments, which demonstrated that circUBAP2 inhibited TNBC sensitivity to DDP through miR-300/ASF1B axis. Furthermore, it was discovered that ASF1B activated PI3K/AKT/mTOR signaling to facilitate the DDP resistance of TNBC cells. In summary, this research revealed a novel regulatory mechanism that circUBAP2 functioned as ceRNA of miR-300 to upregulate ASF1B, which further triggered the PI3K/AKT/mTOR (PAM) signaling to enhance the DDP resistance of TNBC.

A Novel Circular RNA CircBRAP May Be Used as an Early Predictor of Preeclampsia and Its Potential Mechanism

Preeclampsia (PE), a pregnancy-related multisystem syndrome, is one of the leading causes of maternal and fetal mortality worldwide. The aim of this study was to combine the plasma protein soluble Fms-related tyrosine kinase 1 (sFLT1) levels with uterine artery Doppler ultrasound findings and CircBRAP levels during the first trimester to predict the occurrence of preeclampsia and to explore the potential mechanism by which CircBRAP functions in preeclampsia. Here, we used qRT-PCR to investigate the expression of CircBRAP in forty-nine pairs of plasma specimens and placental tissues from preeclampsia patients and control subjects. The uterine artery (UtA) pulsatility index (PI) was measured using four-dimensional color Doppler ultrasound, and the sFLT1 levels were evaluated by human immunoassay. Exogenous upregulation or downregulation of CircBRAP expression in TEV-1 trophoblast cells was performed to investigate the role of CircBRAP in cell biological behavior. Mechanistically, luciferase reporter, RNA immunoprecipitation (RIP), and biotin-coupled RNA pull-down assays were conducted to verify the relationship between CircBRAP and sFLT1 in TEV-1 cells. The results showed that the predictive power was strengthened when the plasma sFLT1 and CircBRAP levels were combined with the UtA-PI to predict preeclampsia occurrence. Our study also revealed that CircBRAP may regulate miR-106b and the HIF-2α axis to modulate the proliferation, invasion, and apoptosis of TEV-1 trophoblast cells. In summary, placenta-derived CircBRAP in plasma may be a novel biomarker for preeclampsia that, together with plasma sFLT1 levels and uterine artery Doppler ultrasound findings, can more effectively predict preeclampsia, and CircBRAP may play a potential role in preeclampsia.