Upregulation of circRNA hsa_circ_0008726 in Pre-eclampsia Inhibits Trophoblast Migration, Invasion, and EMT by Regulating miR-345-3p/RYBP Axis

Inhibition of hsa_circ_0003314 contributes to trophoblast cell migration and invasion and inhibits pyroptosis in preeclampsia

Inflammation is a key contributor to the development of preeclampsia. Recent studies suggest that circular RNAs (circRNAs) may serve as potential therapeutic targets for this disease, though their specific functions remain incompletely understood. In this study, we investigated the role of hsa_circ_0003314 in preeclampsia pathogenesis. The interaction between hsa_circ_0003314 and microRNA (miR)-1827 was validated using RNA pull-down and luciferase reporter assays, while the binding of miR-1827 to the 3'-UTR of caspase-5 was confirmed by RNA immunoprecipitation and luciferase reporter assays. Pyroptotic cells were quantified by flow cytometry based on the percentage of caspase-1/propidium iodide (PI) double-positive cells. Enzyme-linked immunosorbent assay (ELISA) was performed to measure interleukin (IL)-1β concentrations in the culture supernatant. The migration and invasion abilities of HTR-8/SVneo cells were evaluated using Transwell assays. We found that hsa_circ_0003314 expression was upregulated in HTR-8/SVneo cells subjected to hypoxia/reoxygenation (H/R) treatment. Silencing hsa_circ_0003314 enhanced cell migration, invasion, and epithelial-mesenchymal transition (EMT), while reducing the expression of pyroptosis-related proteins, GSDMD-N and HMGB1. The proportion of pyroptotic cells was significantly decreased upon hsa_circ_0003314 knockdown in H/R-treated cells. Mechanistically, hsa_circ_0003314 functions as a molecular sponge for miR-1827, thereby regulating caspase-5 expression. Notably, caspase-5 overexpression rescued the effects of hsa_circ_0003314 knockdown, restoring pyroptosis markers and suppressing the enhanced migratory and invasive behavior of HTR-8/SVneo cells. In conclusion, silencing hsa_circ_0003314 promotes migration, invasion, and EMT in H/R-treated HTR-8/SVneo cells by inhibiting caspase-5-mediated pyroptosis through the sequestration of miR-1827. These findings identify hsa_circ_0003314 as a promising therapeutic target in the treatment of preeclampsia.

Extracellular Vesicles Alter Trophoblast Function in Pregnancies Complicated by COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and resulting coronavirus disease (COVID-19) cause placental dysfunction, which increases the risk of adverse pregnancy outcomes. While abnormal placental pathology resulting from COVID-19 is common, direct infection of the placenta is rare. This suggests that pathophysiology associated with maternal COVID-19, rather than direct placental infection, is responsible for placental dysfunction. We hypothesized that maternal circulating extracellular vesicles (EVs), altered by COVID-19 during pregnancy, contribute to placental dysfunction. To examine this hypothesis, we characterized circulating EVs from pregnancies complicated by COVID-19 and tested their effects on trophoblast cell physiology in vitro. Trophoblast exposure to EVs isolated from patients with an active infection (AI), but not controls, altered key trophoblast functions including hormone production and invasion. Thus, circulating EVs from participants with an AI, both symptomatic and asymptomatic cases, can disrupt vital trophoblast functions. EV cargo differed between participants with COVID-19, depending on the gestational timing of infection, and Controls, which may contribute to the disruption of the placental transcriptome and morphology. Our findings show that COVID-19 can have effects throughout pregnancy on circulating EVs, and circulating EVs are likely to participate in placental dysfunction induced by COVID-19.

The Deubiquitinating Enzyme USP4 Promotes Trophoblast Dysfunction by Stabilizing RYBP

Previous studies have suggested that impaired spiral artery remodeling, placental dysfunction, and insufficient trophoblast infiltration are the etiology and pathogenesis of Preeclampsia (PE). Ring 1 and YY1 binding protein (RYBP) has been reported to be associated with trophoblast dysfunction. However, the molecular mechanism of RYBP involved in trophoblasts in the pathogenesis of PE is poorly defined. RYBP and Ubiquitin-specific peptidase 4 (USP4) mRNA levels were determined using real-time quantitative polymerase chain reaction (RT-qPCR). RYBP, USP4, p-PI3K, PI3K, p-AKT, and AKT protein levels were measured using western blot assay. Cell viability, proliferation, apoptosis, invasion, and migration were assessed using 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, transwell, and wound healing assays. After ubibrowser database analysis, the interaction between USP4 and RYBP was verified using Co-immunoprecipitation (CoIP) assay. RYBP and USP4 expression were upregulated in placental tissues from PE patients. By using JEG-3 and HTR-8/SVneo trophoblast cells, RYBP overexpression or USP4 upregulation could hinder cell viability, proliferation, invasion, migration, and promote apoptosis. Mechanistically, USP4 could trigger the deubiquitination of RYBP and prevent its degradation. In addition, USP4 repressed the PI3K/AKT signaling pathway by regulating RYBP. In total, Decreased USP4-mediated ubiquitination results in an adverse impact on trophoblast function by enhancing RYBP expression, providing a novel therapeutic target for PE.

Role of circular RNAs in preeclampsia (Review)

Preeclampsia (PE) is a hypertensive disorder of pregnancy characterized by new-onset hypertension and proteinuria after 20 weeks of gestation, which affects 3-8% of pregnant individuals worldwide each year. Prevention, diagnosis and treatment of PE are some of the most important problems faced by obstetrics. There is growing evidence that circular RNAs (circRNAs) are involved in the pathogenesis of PE. The present review summarizes the research progress of circRNAs and then describes the expression patterns of circRNAs in PE and their functional mechanisms affecting PE development. The role of circRNAs as biomarkers for the diagnosis of PE, and the research status of circRNAs in PE are summarized in the hope of finding novel strategies for the prevention and treatment of PE.

Unveiling the Network regulatory mechanism of ncRNAs on the Ferroptosis Pathway: Implications for Preeclampsia

Non-coding RNAs (ncRNAs) are transcripts originating from the genome that do not serve as templates for protein synthesis. They function as epigenetic and translational regulators in various pathophysiological mechanisms, including cell proliferation and apoptosis. The ferroptosis signaling pathway, a novel mode of cell death, participates in numerous pathophysiological processes. Its signaling transmission is both complex and precise, featuring interconnected and interdependent pathways. Recent studies suggest that ncRNAs can finely regulate key genes in the ferroptosis pathway, thus modulating cellular functions, reducing oxidative stress, and maintaining maternal-fetal interface homeostasis. Future strategies targeting the ncRNA/ferroptosis axis may provide new perspectives and potential intervention points for treating preeclampsia. This article clarifies how the ncRNA/ferroptosis axis impacts preeclampsia, revealing how ncRNAs interact with ferroptosis, and pinpointing new molecular targets for the treatment of preeclampsia, thereby providing theoretical support for clinical strategies.

CircPAPPA2 plays a role in preeclampsia pathogenesis via regulation of the miR-942/miR-5006-3p

CircRNAs are a class of endogenous non-coding RNAs implicated in the pathogenesis of many pregnancy related diseases, one of which is pre-eclampsia (PE). This study aims to investigate the role of CircPAPPA2 (circbase ID: hsa_circ_0015382) in regulating the migration and invasion of trophoblast cells. RNA sequencing was used to identify the differentially expressed circRNAs in placenta of PE and normal pregnant women. Quantitative polymerase chain reaction (qRT-PCR) was used to verify the expression of circPAPPA2 and two miRNAs (miR-942-5p, 5006-3p) in placenta of PE and normal pregnant women. CCK8 and transwell experiments were performed to assess the function of circPAPPA2 in PE development.The interaction between circPAPPA2 and miR-942-5p/miR-5006-3p was verified by dual-luciferase reporter assay. Finally, bioinformatics analyzed with gene ontology, Kyoto Encyclopedia of the target genes. The results showed that the expression of circPAPPA2 was increased in placenta of PE pregnant women. Also, circPAPPA2 impedes trophoblasts cell proliferation and invasion. Moreover, the expression of circPAPPA2 was positively correlated with systolic blood pressure and urine protein. In addition, circPAPPA2 serves as a sponge of miR-942-5p and miR-5006-3p. In conclusion, CircPAPPA2 regulates trophoblasts cell proliferation and invasion by mediating the miR-942/miR-5006-3p.

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.

Extracellular vesicles alter trophoblast function in pregnancies complicated by COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and resulting coronavirus disease (COVID-19) causes placental dysfunction, which increases the risk of adverse pregnancy outcomes. While abnormal placental pathology resulting from COVID-19 is common, direct infection of the placenta is rare. This suggests that pathophysiology associated with maternal COVID-19, rather than direct placental infection, is responsible for placental dysfunction and alteration of the placental transcriptome. We hypothesized that maternal circulating extracellular vesicles (EVs), altered by COVID-19 during pregnancy, contribute to placental dysfunction. To examine this hypothesis, we characterized maternal circulating EVs from pregnancies complicated by COVID-19 and tested their effects on trophoblast cell physiology in vitro . We found that the gestational timing of COVID-19 is a major determinant of circulating EV function and cargo. In vitro trophoblast exposure to EVs isolated from patients with an active infection at the time of delivery, but not EVs isolated from Controls, altered key trophoblast functions including hormone production and invasion. Thus, circulating EVs from participants with an active infection, both symptomatic and asymptomatic cases, can disrupt vital trophoblast functions. EV cargo differed between participants with COVID-19 and Controls, which may contribute to the disruption of the placental transcriptome and morphology. Our findings show that COVID-19 can have effects throughout pregnancy on circulating EVs and circulating EVs are likely to participate in placental dysfunction induced by COVID-19.

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.

Characterization of the lncRNA-mediated ceRNA regulatory networks in preeclampsia by integrated bioinformatics

Preeclampsia (PE) is a significant threat to all pregnancies that is highly associated with maternal mortality and developmental disorders in infants. However, the etiopathogenesis of this condition remains unclear. This study aims to explore the regulatory roles of long noncoding RNAs (lncRNAs) and the mediated competing endogenous RNAs (ceRNA) in the etiopathogenesis of PE through analysis of lncRNA expression patterns in PE and healthy pregnant women (HPW), as well as the construction of lncRNA-mediated ceRNA regulatory networks using bioinformatics. A total of 896 significant differentially expressed lncRNAs, including 586 upregulated lncRNAs and 310 downregulated lncRNAs, were identified in comparison between PE and HPW. Analysis of these differential expressed lncRNAs revealed their predominant enrichment in molecular functions such as sphingosine-1-phosphate phosphatase activity, lipid phosphatase activity, phosphatidate phosphatase activity, thymidylate kinase activity, and UMP kinase activity. Moreover, these differential expressed lncRNAs were predominantly enriched in KEGG analyses such as fat digestion and absorption, lysine degradation, ether lipid metabolism, glycerolipid metabolism, and sphingolipid metabolism. Two ceRNA regulatory networks were constructed based on ceRNA score, including one that had 31 upregulated lncRNAs, 11 downregulated miRNAs, and 34 upregulated mRNAs, while the other contained 128 downregulated lncRNAs, 40 upregulated miRNAs, and 113 downregulated mRNAs. These results may provide a clue to explore the roles of lncRNAs in the etiopathogenesis of PE.

Circular RNAs in the Origin of Developmental Lung Disease: Promising Diagnostic and Therapeutic Biomarkers

Circular RNA (circRNA) is a newly discovered noncoding RNA that regulates gene transcription, binds to RNA-related proteins, and encodes protein microRNAs (miRNAs). The development of molecular biomarkers such as circRNAs holds great promise in the diagnosis and prognosis of clinical disorders. Importantly, circRNA-mediated maternal-fetus risk factors including environmental (high altitude), maternal (preeclampsia, smoking, and chorioamnionitis), placental, and fetal (preterm birth and low birth weight) factors are the early origins and likely to contribute to the occurrence and progression of developmental and pediatric cardiopulmonary disorders. Although studies of circRNAs in normal cardiopulmonary development and developmental diseases have just begun, some studies have revealed their expression patterns. Here, we provide an overview of circRNAs’ biogenesis and biological functions. Furthermore, this review aims to emphasize the importance of circRNAs in maternal-fetus risk factors. Likewise, the potential biomarker and therapeutic target of circRNAs in developmental and pediatric lung diseases are explored.

The Role of Placental Non-Coding RNAs in Adverse Pregnancy Outcomes

Non-coding RNAs (ncRNAs) are transcribed from the genome and do not encode proteins. In recent years, ncRNAs have attracted increasing attention as critical participants in gene regulation and disease pathogenesis. Different categories of ncRNAs, which mainly include microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), are involved in the progression of pregnancy, while abnormal expression of placental ncRNAs impacts the onset and development of adverse pregnancy outcomes (APOs). Therefore, we reviewed the current status of research on placental ncRNAs and APOs to further understand the regulatory mechanisms of placental ncRNAs, which provides a new perspective for treating and preventing related diseases.

Re-expression of circ_0043610 contributes to trophoblast dysfunction through the miR-558/RYBP pathway in preeclampsia

An increasing number of data have shown the pathogenesis of preeclampsia (PE) involves circular RNA (circRNA). The study aims to investigate the function and the potential mechanism of circ_0043610 in PE. The study was performed on two human placental trophoblastic cell lines (JEG-3 and HTR-8/SVneo). The expression of circ_0043610, microRNA-558 (miR-558), and RING1 and YY1 binding protein (RYBP) was detected by quantitative real-time polymerase chain reaction. The protein levels of N-cadherin, E-cadherin, and RYBP were assessed by Western blotting. Cell viability, proliferation, apoptosis, invasion, and migration were evaluated by cell counting kit-8, 5-Ethynyl-29-deoxyuridine, flow cytometry analysis, transwell invasion assay, and wound-healing assay, respectively. Dual-luciferase reporter assay, RNA immunoprecipitation assay, and RNA pull-down assay were performed to identify the associations among circ_0043610, miR-558, and RYBP. Compared with normal placental controls, the increased expression of circ_0043610 and RYBP and the decreased miR-558 expression were detected in PE placental tissues. The overexpression of circ_0043610 led to decreased trophoblast cell proliferation, invasion, and migration but increased cell apoptosis. Mechanistically, circ_0043610 acted as a miR-558 sponge, and miR-558 bound to RYBP. Besides, miR-558 introduction remitted circ_0043610-mediated effects in JEG-3 and HTR-8/SVneo cells. Moreover, RYBP participated in the regulation of miR-558 on trophoblast cell behaviors. Further, the ectopic expression of circ_0043610 led to RYBP upregulation through miR-558. Circ_0043610 induced RYBP production to promote trophoblast dysfunction by binding to miR-558 in PE.

circRNA circ_0055724 Inhibits Trophoblastic Cell Line HTR-8/SVneo’s Invasive and Migratory Abilities via the miR-136/N-Cadherin Axis

Preeclampsia (PE) is one of the major causes of morbidity and mortality in pregnancy. According to recent research, circular RNAs (circRNA) may act as sponges for microRNAs (miRNAs) and modulate gene expression. Low expression of hsa_circ_0055724 (circ_0055724) in PE tissues was recently reported in literatures. However, its mechanism and function have not been reported. Therefore, we were committed to investigating the role and mechanism of circ_0055724 in PE. Our study first verified the low expression of circ_0055724 in PE tissues. Overexpression or knockdown of circ_0055724 enhances/weakens the trophoblast cell survival, migration, and invasion. Furthermore, CircInteractome predicted the binding sites of circ_0055724 and miR-136, while Starbase predicted miR-136 targeted N-cadherin. Luciferase reporter gene assay confirmed that circ_0055724 directly interacts with miR-136 and miR-136 directly interacts with N-cadherin. More results indicated that high expression of miR-136 and low expression of N-cadherin appeared in PE. Increased expression of circ_0055724 resulted in decreased miR-136 but increased N-cadherin expression. Hence, circ_0055724 and N-cadherin were positively correlated, while circ_0055724 and miR-136 had a negative correlation. In terms of mechanism, circ_0055724 may induce the expression of N-cadherin and regulate the proliferation, migration, and invasion of trophoblast cells through decreasing miR-136, which can be a promising biomarker for early diagnosis and prognosis of patients with PE.

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.