Circular RNA hsa_circ_0007121 regulates proliferation, migration, invasion, and epithelial-mesenchymal transition of trophoblast cells by miR-182-5p/PGF axis in preeclampsia

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.

CPEB2 inhibits preeclampsia progression by regulating SSTR3 translation through polyadenylation

AIMS

Trophoblast cell dysfunction is one of the important factors leading to preeclampsia (PE). Cytoplasmic polyadenylation element-binding 2 (CPEB2) has been found to be differentially expressed in PE patients, but whether it mediates PE process by regulating trophoblast cell function is unclear.

METHODS

The expression of CPEB2 and somatostatin receptor 3 (SSTR3) was detected by quantitative real-time PCR, Western blot (WB) and immunofluorescence staining. Cell functions were analyzed by CCK-8 assay, EdU assay, flow cytometry and transwell assay. Epithelial-mesenchymal transition (EMT)-related protein levels were detected by WB. The interaction of CPEB2 and SSTR3 was confirmed by RIP assay, dual-luciferase reporter assay and PCR poly(A) tail assay. Animal experiments were performed to explore the effect of CPEB2 on PE progression in vivo, and the placental tissues of rat were used for H&E staining, immunohistochemical staining and TUNEL staining.

RESULTS

CPEB2 was lowly expressed in PE patients. CPEB2 upregulation accelerated trophoblast cell proliferation, migration, invasion and EMT, while its knockdown had an opposite effect. CPEB2 bound to the CPE site in the 3'-UTR of SSTR3 mRNA to suppress SSTR3 translation through reducing poly(A) tails. Besides, SSTR3 overexpression suppressed trophoblast cell proliferation, migration, invasion and EMT, while its silencing accelerated trophoblast cell functions. However, these effects could be reversed by CPEB2 upregulation and knockdown, respectively. In vivo experiments, CPEB2 overexpression relieved histopathologic changes, inhibited apoptosis, promoted proliferation and enhanced EMT in the placenta of PE rat by decreasing SSTR3 expression.

CONCLUSION

CPEB2 inhibited PE progression, which promoted trophoblast cell functions by inhibiting SSTR3 translation through polyadenylation.

Deciphering the Epigenetic Landscape: Placental Development and Its Role in Pregnancy Outcomes

The placenta stands out as a unique, transitory, and multifaceted organ, essential to the optimal growth and maturation of the fetus. Functioning as a vital nexus between the maternal and fetal circulatory systems, it oversees the critical exchange of nutrients and waste. This exchange is facilitated by placental cells, known as trophoblasts, which adeptly invade and remodel uterine blood vessels. Deviations in placental development underpin a slew of pregnancy complications, notably fetal growth restriction (FGR), preeclampsia (PE), recurrent spontaneous abortions (RSA), and preterm birth. Central to placental function and development is epigenetic regulation. Despite its importance, the intricate mechanisms by which epigenetics influence the placenta are not entirely elucidated. Recently, the scientific community has turned its focus to parsing out the epigenetic alterations during placental development, such as variations in promoter DNA methylation, genomic imprints, and shifts in non-coding RNA expression. By establishing correlations between epigenetic shifts in the placenta and pregnancy complications, researchers are unearthing invaluable insights into the biology and pathophysiology of these conditions. This review seeks to synthesize the latest findings on placental epigenetic regulation, spotlighting its crucial role in shaping fetal growth trajectories and development. Through this lens, we underscore the overarching significance of the placenta in the larger narrative of gestational health.

Circ_0001861 facilitates trophoblast cell proliferation, migration, invasion and epithelial-mesenchymal transition via the miR-296-5p/forkhead box protein 1 pathway in preeclampsia

BACKGROUND

Preeclampsia (PE) is one of the leading causes of maternal mortality and placental trophoblastic disorders. Recent studies reported that circular RNAs (circRNAs) were involved in PE pathogenesis. However, the role of circ_0001861 in PE progression is largely unknown.

METHODS

The RNA expression of circ_0001861, forkhead box protein 1 (FOXP1) and microRNA-296-5p (miR-296-5p) was detected by quantitative real-time polymerase chain reaction (qRT-PCR) assay. Western blot assay was performed to examine the protein levels of FOXP1 and epithelial-mesenchymal transition (EMT) markers. Cell viability, proliferation, migration and invasion were detected by cell counting kit-8, 5-ethynyl-2'-deoxyuridine, and transwell assays. Luciferase reporter assay, RNA pull-down assay, and RNA immunoprecipitation (RIP) assay were conducted to explore the interaction between miR-296-5p and circ_0001861 or FOXP1.

RESULTS

Circ_0001861 and FOXP1 were downregulated but miR-296-5p was upregulated in PE placenta. Upregulation of circ_0001861 facilitated trophoblast cell proliferation, migration, invasion and EMT. Mechanistically, circ_0001861 sponged miR-296-5p to elevate FOXP1 expression, thus promoting trophoblast cell progression.

CONCLUSION

The circ_0001861/miR-296-5p/FOXP1 axis plays a critical role in trophoblast cell proliferation, migration, invasion and EMT, which may provide a novel insight into developing potential therapeutic targets for PE.

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.

Circ-CCS regulates oxaliplatin resistance via targeting miR-874-3p/HK2 axis in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is a malignancy that threatens the patient's life. Previous reports showed that circular RNAs (circRNAs) can affect CRC development. Herein, we demonstrated the characters of circular RNA copper chaperone for superoxide dismutase (circ-CCS) in CRC tissues and cells.

METHODS

Circ-CCS, CCS mRNA, microRNA-874-3p (miR-874-3p) and hexokinase 2 (HK2) were indicated by qRT-PCR and western blot in CRC. The cell roles were examined. Additionally, the interaction between miR-874-3p and circ-CCS or HK2 was forecasted by the bioinformatics method and assessed by dual-luciferase reporter assay. Finally, the mouse test was implemented to demonstrate the effect of circ-CCS in vivo.

RESULTS

Circ-CCS and HK2 were increased, whereas miR-874-3p was diminished in CRC. Circ-CCS lack subdued the IC₅₀ value of oxaliplatin, cell proliferation, migration, invasion and glycolysis metabolism in CRC cells, while it endorsed cell apoptosis. Furthermore, miR-874-3p was validated as having a tumor repressive effect in CRC cells by restraining HK2. The results also showed that HK2 could regulate the development of CRC. In mechanism, circ-CCS targeted miR-874-3p to control HK2. In addition, circ-CCS knock-down also attenuated tumor growth in mice.

CONCLUSION

Circ-CCS expedited CRC through miR-874-3p/HK2.

circ_0004904 regulates the trophoblast cell in preeclampsia via miR-19b-3p/ARRDC3 axis

Circular RNAs have been demonstrated to act as vital participants in various diseases, including preeclampsia (PE). This study aimed to research the effects of circ_0004904 on PE. The contents of circ_0004904, microRNA-19b-3p (miR-19b-3p) and arrestin domain containing 3 (ARRDC3) were quantified by quantitative real-time PCR and western blot. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and 5-ethynyl-2'-deoxyuridine assays were enforced to assess cell proliferation. The transwell assay and flow cytometry were applied to detect the cell migration, invasion, and apoptosis. The liaison between miR-19b-3p and circ_0004904 or ARRDC3 was demonstrated by dual-luciferase reporter assay. Thereafter, circ_0004904 and ARRDC3 were augmented, and miR-19b-3p was restrained in PE. Circ_0004904 silencing contributed to cell proliferation, migration, and invasion, but restrained cell apoptosis in trophoblast cells. Further, miR-19b-3p was a target of circ_0004904, and miR-19b-3p could target ARRDC3. Additionally, circ_0004904 accelerated PE evolution via changing ARRDC3 level by binding to miR-19b-3p. In all, circ_0004904 encouraged PE progress via miR-19b-3p/ARRDC3 axis.

Circ_0001326 suppresses trophoblast cell proliferation, invasion, migration and epithelial-mesenchymal transition progression in preeclampsia by miR-188-3p/HtrA serine peptidase 1 axis

BACKGROUND

It has been reported that the alteration of circular RNAs (circRNAs) during preeclampsia (PE) can be associated with the pathogenesis of this disease. Herein, this work investigated the potential functions and mechanism of circ_0001326 in PE process.

METHODS

The levels of genes and proteins were evaluated by quantitative real-time PCR (qRT-PCR) and western blotting. The functional experiments were conducted using cell counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, transwell, and wound healing assays, respectively. The binding between miR-188-3p and circ_0001326 or HtrA serine peptidase 1 (HTRA1) was verified by bioinformatics analysis and dual-luciferase reporter assays.

RESULTS

Circ_0001326 and HTRA1 expression was increased, while miR-188-3p expression was decreased in the placental tissues of preeclamptic singleton pregnant women compared with the normal pregnant women. Functionally, up-regulation of circ_0001326 or HTRA1, or down-regulation of miR-188-3p led to the arrest of cell growth, invasion, migration and epithelial-mesenchymal transition (EMT) process in trophoblast cells. Mechanistically, circ_0001326 acted as a sponge for miR-188-3p, which directly targeted HTRA1. Moreover, circ_0001326 could regulate HTRA1 through sequestering miR-188-3p. A series of rescue experiments showed that miR-188-3p reversed the inhibitory effects of circ_0001326 knockdown on above behaviors of trophoblast cells. Besides that, HTRA1 silencing attenuated the action of miR-188-3p inhibitor on trophoblast cell phenotype alteration.

CONCLUSION

Our study demonstrated that circ_0001326 could promote trophoblast cell proliferation, invasion, migration and EMT in PE by miR-188-3p/HTRA1 axis, indicating a novel insight into the pathogenesis of PE.

CircSTAM inhibits migration and invasion of trophoblast cells by regulating miR-148a-5p/PTEN axis

BACKGROUND

The mechanisms underlying the pathogenesis of preeclampsia (PE) remains unclear. Exploring the molecular players in PE progression can provide insights into targeted therapy.

METHODS

The expression levels of circSTAM in placental chorionic tissues of PE patients and normal pregnant women were compared by RT-qPCR. CircSTAM was knocked down by small interfering RNA to investigate its role in migration, invasion and epithelial-mesenchymal transformation (EMT) of trophoblast HTR-8/SVneo cells. The downstream target of circSTAM was predicted using online bioinformatics resources, and their molecular interaction was examined by luciferase reporter assay.

RESULTS

CircSTAM was upregulated in PE placenta tissues in comparison to normal placental tissues. CircSTAM knockdown significantly enhanced cellular invasion, migration, as well as EMT. Mir-148a-5p was identified as a target of circSTAM to regulate cell migration and invasion. Mir-148a-5p negatively regulated PTEN expression in trophoblast HTR-8 /SVneo cells.

CONCLUSION

In summary, circSTAM upregulation in PE trophoblasts promoted the invasion, migration and EMT. CircSTAM may modulate trophoblast phenotype by impinging on mir-148a-5p/PTEN axis. These data provided novel insights into the pathogenesis of PE.

Hsa_circ_0088196 suppresses trophoblast migration and invasion by the miR-525-5p/ABL1 axis and the PI3K/AKT signaling pathway

Our study aimed to explore the role of circ_0088196 (circular TNC [circTNC]) in trophoblast invasion and migration in preeclampsia (PE) both in vitro and in vivo. CircTNC, miR-525-5p, and ABL1 expression in trophoblast HTR8/SVneo cells were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability, migration, and invasion were detected by Cell Counting Kit-8 (CCK-8), wound healing, and Transwell assays. The binding between circTNC (or ABL1) and miR-525-5p was validated by RNA pulldown and luciferase reporter assays. The mouse model of PE was injected with sh-circTNC and the effects of circTNC knockdown on the mean artery pressure, urine protein concentration, and fetal survival number of pregnant mice were examined. The expression of MMP-2, MMP-9, and PI3K/AKT pathway molecules in placental tissues was assessed by immunohistochemistry, qRT-PCR, and western blot analysis. CircTNC overexpression inhibited cell invasion and migration, but did not influence cell proliferation. CircTNC bound with miR-525-5p, whose knockdown repressed cell invasion and migration, while it exerted no effect on cell proliferation. ABL1, a target of miR-525-5p, attenuated cell migration and invasion, without influence on cell viability. Importantly, either miR-525-5p overexpression or ABL1 depletion antagonized the repression of upregulated circTNC on trophoblast cell migration and invasion, MMP-2 and MMP-9 expression, and the PI3K/AKT pathway. CircTNC knockdown alleviated PE symptoms in pregnant mice. CircTNC knockdown promoted the trophoblast invasiveness in mice placenta by upregulating MMP-2/9 expression and suppressing the PI3K/AKT pathway. Circ_0088196 represses trophoblast invasion and migration both in vitro and in vivo via regulating the miR-525-5p/ABL1 axis and activating the PI3K/AKT pathway.

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.

Circ_0005714/miR-223-3p/ADAM9 regulatory axis affects proliferation, migration, invasion, and angiopoiesis in trophoblast cells

BACKGROUND

Circular RNAs (circRNAs) have critical roles in various types of diseases, including preeclampsia (PE). Circ_0005714 function in PE was explored in this study.

METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed for level analysis of circ_0005714, micoRNA-223-3p (miR-223-3p), and a disintegrin and metalloproteinase 9 (ADAM9). Cell Counting Kit-8 (CCK-8) and colony formation assays were used for cell viability and colony formation detection. Cell proliferation was determined by EdU assay. The determination of migration and invasion was conducted by wound healing assay and transwell assay. Tube formation assay was applied to assess angiopoiesis. Target binding analysis was performed by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Western blot was used for protein examination.

RESULTS

Circ_0005714 was highly expressed in PE placenta tissues. The expression promotion of circ_0005714 reduced proliferation, migration, invasion, and angiopoiesis in trophoblast cells. Furthermore, circ_0005714 acted as a molecular sponge for miR-223-3p and the effects of circ_0005714 on trophoblast cells were achieved by sponging miR-223-3p. Moreover, miR-223-3p could target ADAM9 and knockdown of ADAM9 reversed cell progression inhibition induced by miR-223-3p inhibitor. In addition, circ_0005714 upregulated the ADAM9 expression and inactivated the Wnt/β-catenin pathway through targeting miR-223-3p.

CONCLUSIONS

All results manifested that circ_0005714 retarded the progression of PE by mediating the miR-223-3p/ADAM9 signal network.

The Role of Non-Coding RNAs in the Human Placenta

Non-coding RNAs (ncRNAs) play a central and regulatory role in almost all cells, organs, and species, which has been broadly recognized since the human ENCODE project and several other genome projects. Nevertheless, a small fraction of ncRNAs have been identified, and in the placenta they have been investigated very marginally. To date, most examples of ncRNAs which have been identified to be specific for fetal tissues, including placenta, are members of the group of microRNAs (miRNAs). Due to their quantity, it can be expected that the fairly larger group of other ncRNAs exerts far stronger effects than miRNAs. The syncytiotrophoblast of fetal origin forms the interface between fetus and mother, and releases permanently extracellular vesicles (EVs) into the maternal circulation which contain fetal proteins and RNA, including ncRNA, for communication with neighboring and distant maternal cells. Disorders of ncRNA in placental tissue, especially in trophoblast cells, and in EVs seem to be involved in pregnancy disorders, potentially as a cause or consequence. This review summarizes the current knowledge on placental ncRNA, their transport in EVs, and their involvement and pregnancy pathologies, as well as their potential for novel diagnostic tools.

Circ_0007611 stimulates IL-1 receptor accessory protein to inhibit trophoblast cell proliferation and induce cell apoptosis

Preeclampsia (PE) is a common pregnancy disorder, and mounting evidence has revealed that circular RNA participates in PE development. However, the detailed molecular mechanism of circ_0007611 in PE progression remains unknown. RNA expressions of circ_0007611, microRNA-558 (miR-558), and IL-1 receptor accessory protein (IL1RAP) were detected by quantitative real-time polymerase chain reaction. Cell proliferation was investigated by clonogenicity, 5-Ethynyl-29-deoxyuridine, and DNA content quantitation assays. Cell apoptotic rate and angiogenesis were analyzed by cell apoptosis and tube formation assays, respectively. Protein expression was detected by western blot. The binding relationship between miR-558 and circ_0007611 or IL1RAP was identified by a dual-luciferase reporter or RNA immunoprecipitation assay. Circ_0007611 and IL1RAP expressions were significantly upregulated, while miR-558 was downregulated in the placental tissues of PE women in comparison with normal placental tissues. Functionally, circ_0007611 overexpression inhibited trophoblast cell proliferation and angiogenesis and induced cell apoptosis; however, circ_0007611 downregulation showed the opposite effects. Mechanistically, circ_0007611 acted as a miR-558 sponge, and miR-558 bound to IL1RAP. Besides, miR-558 overexpression or IL1RAP absence relieved circ_0007611-induced trophoblast cell dysfunction. Moreover, miR-558 contributed to cell proliferation and tube formation and inhibited cell apoptosis by reducing IL1RAP expression in trophoblast cells. Circ_0007611 aggravated trophoblast cell disorders by the miR-558/IL1RAP pathway in PE.

Circ_0037078 promotes trophoblast cell proliferation, migration, invasion and angiogenesis by miR-576-5p/IL1RAP axis

BACKGROUND

Preeclampsia (PE) is a common hypertensive disorder of pregnancy. Recent studies have suggested that circular RNAs (circRNAs) play a pathological role in PE. Herein, this study aimed to investigate the action and mechanism of circ_0037078 in PE process.

METHODS

The quantitative real-time PCR (qRT-PCR) and Western blot were used to determine the expression levels of RNAs and genes. Cell proliferation, migration, invasion and angiogenesis were evaluated by using cell counting kit-8 (CCK-8), colony formation, transwell, and tube formation assays, respectively. The target relation between miR-576-5p and IL1RAP (Interleukin-1 receptor accessory protein) and circ_0037078 was predicted by bioinformatics analysis and verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays.

RESULTS

Circ_0037078 expression was higher in placental tissues of patients with PE than that of normal control. Knockdown of circ_0037078 led to an enhancement of the proliferation, migration, invasion, and angiogenesis in trophoblast cells. Mechanistically, circ_0037078 acted as a sponge for miR-576-5p, thus elevating the expression of IL1RAP, which was targeted by IL1RAP. Further rescue experiments suggested that miR-576-5p inhibition reversed the effects of circ_0037078 knockdown on above behaviors of trophoblast cells. Moreover, miR-576-5p overexpression enhanced the proliferative, migratory, invasive, angiogenic phenotypes of trophoblast cells, which were attenuated by IL1RAP up-regulation.

CONCLUSION

Circ_0037078 knockdown promotes trophoblast cell proliferation, migration, invasion, and angiogenesis in vitro by miR-576-5p/IL1RAP axis, providing a novel insight into the etiology of PE.

Significance of Sex Differences in ncRNAs Expression and Function in Pregnancy and Related Complications

In the era of personalized medicine, fetal sex-specific research is of utmost importance for comprehending the mechanisms governing pregnancy and pregnancy-related complications. In recent times, noncoding RNAs (ncRNAs) have gained increasing attention as critical players in gene regulation and disease pathogenesis, and as candidate biomarkers in human diseases as well. Different types of ncRNAs, including microRNAs (miRNAs), piwi-interacting RNAs (piRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), participate in every step of pregnancy progression, although studies taking into consideration fetal sex as a central variable are still limited. To date, most of the available data have been obtained investigating sex-specific placental miRNA expression. Several studies revealed that miRNAs regulate the (patho)-physiological processes in a sexually dimorphic manner, ensuring normal fetal development, successful pregnancy, and susceptibility to diseases. Moreover, the observation that ncRNA profiles differ according to cells, tissues, and developmental stages of pregnancy, along with the complex interactions among different types of ncRNAs in regulating gene expression, strongly indicates that more studies are needed to understand the role of sex-specific ncRNA in pregnancy and associated disorders.

Circ_0007121 Facilitates Trophoblastic Cell Proliferation, Migration, and Invasion via the Regulation of the miR-421/ZEB1 Axis in Preeclampsia

Noncoding circular RNAs (circRNAs) have participated in the progression of preeclampsia (PE) via inhibiting microRNAs (miRNAs) to regulate gene expression. This study was designed to explore the miRNA/mRNA mechanism of hsa_circ_0007121 (circ_0007121) in PE. The expression detection of circ_0007121, microRNA-421 (miR-421), and zinc finger E-box binding homeobox 1 (ZEB1) was performed by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was analyzed by Cell Counting Kit-8 (CCK-8) assay. Transwell assay was used to determine cell migration and invasion. Cell apoptosis was evaluated using flow cytometry. The protein levels of epithelial-mesenchymal transition (EMT) markers and ZEB1 were measured via western blot. The interaction between miR-421 and circ_0007121 or ZEB1 was validated by dual-luciferase reporter assay. The expression detection indicated that circ_0007121 was downregulated in PE patients and the clinical data revealed that circ_0007121 was related to PE. The upregulation of circ_0007121 promoted cell proliferation, migration, invasion, and EMT in trophoblastic cells. Furthermore, circ_0007121 was identified as a sponge of miR-421 and the function of circ_0007121 was dependent on the sponge effect on miR-421. Moreover, ZEB1 was a target of miR-421 and circ_0007121/miR-421 axis could regulate the expression of ZEB1. In addition, miR-421 overexpression repressed trophoblastic cell behaviors through downregulating the ZEB1 level. Altogether, circ_0007121 contributed to the development of trophoblastic cells by regulating the miR-421/ZEB1 axis.

Identification and comparison of circular RNAs in preeclampsia

Background

Preeclampsia (PE) is a pregnancy-specific syndrome, belongs to the gestational hypertension diseases category and is considered among the causes of maternal and perinatal mortality and morbidity. However, the pathogenesis of PE is still vague.

Methods

In the present study, the circular RNA (circRNA) expression patterns of normal pregnant women and PE patients were investigated using whole RNA sequencing.

Results

A total of 151 differential expressed circRNAs were identified including 121 upregulated and 30 downregulated ones. Functional and pathway enrichment analysis was conducted on the differentially expressed circRNAs using Gene Ontology and KEGG databases. The results of this analysis indicated that several crucial biological processes and pathways were enriched in PE patients. circRNA–microRNA (miRNA) interaction analysis indicated that the reported differentially expresse circRNAs may be associated with some regulatory functions through miRNAs in PE patients. Two ceRNAs networks were constructed according to the targeting relationship between circRNAs/miRNAs and miRNAs/mRNAs. One sub-network contained one upregulated circRNA, four downregulated miRNAs and five upregulated mRNAs, and another sub-network contained 10 downregulated circRNAs, 21 upregulated miRNAs and 15 downregulated mRNAs.

Conclusion

CircRNA expression patterns have been investigated and this analysis revealed their potential regulatory mechanisms in PE patients. We constructed the ceRNAs (competing endogenous RNA) to reveal the potential molecular roles of dysregulated circRNAs in the PE patients using RNA sequencing data. circRNA_13301 was the only one upregulated circRNA in ceRNA being targeted by four miRNAs.