CircLRRK1 targets miR-223-3p to inhibit the proliferation, migration and invasion of trophoblast cells by regulating the PI3K/AKT signaling pathway

CircPCNXL2 promotes preeclampsia progression by suppressing trophoblast cell proliferation and invasion via miR-487a-3p/interferon regulatory factor 2 axis

BACKGROUND

Preeclampsia (PE) has culminated in maternal and perinatal sickness and death across the world, affecting approximately 4.6% of pregnancies. Circular RNAs (circRNAs) have been linked to the biology of numerous pathologies, including PE. Here, we investigated the functional role of circPCNXL2 in the progression of PE.

METHODS

We employed the GEO database to get the expression profile of circPCNXL2 in patients with PE. This was followed by the detection of the expression of circPCNXL2 and miR-326 by qRT-PCR. The role of circPCNXL2 on trophoblast cell proliferation, migration, and invasion was confirmed with cell viability assays, the transwell assay, and the colony formation assay. Further, we employed dual luciferase, FISH, RNA pull-down assay and Western blot analysis to determine the interaction between the expression of circPCNXL2, miR-487a-3p, and IRF2.

RESULT

Findings from this study revealed that proliferation and migration of trophoblast cells were significantly increased in the HTR-8/SVneo cells after silencing circPCNXL2. Additionally, knockdown of circPCNXL2 remarkably increased miR-487a-3p expression, while IRF2 expression was remarkably reduced (P < 0.05), indicating the presence of complementary binding sequence on miR-487a-3p with which they sequester circPCNXL2. Rescue experiments revealed that interaction occurs between circPCNXL2, miR-487a-3p, and the IRF2 protein, indicating that circPCNXL2 expression elicits suppression of migration and proliferation of trophoblast cells via the miR-487a-3p/IRF2 pathway.

CONCLUSIONS

We demonstrated that circPCNXL2 upregulation promotes pre-eclampsia by inhibiting proliferation and migration of trophoblast cells via the miR-487a-3p/IRF2 pathway or axis.

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.

The emerging role of microRNA-based therapeutics in the treatment of preeclampsia

Preeclampsia (PE) is a pregnancy complication that is often diagnosed due to elevated blood pressure and proteinuria. Though current research focuses on the identification of novel biomarkers and therapeutic targets, still, there is a lack of clinical validation for the use of biomarkers and therapeutic targets for early diagnosis and treatment of PE. Several molecules are being studied for their potential role in PE. Among them, microRNAs are studied vastly for their role in the diagnosis, prognosis, and treatment of PE. But only a few studies are focused on the therapeutic efficacy of miRNAs in PE. Thus, the relevant articles were identified and discussed in this review. These studies provide evidence that miRNAs are indeed important molecules in PE that have the role of both therapeutic targets and therapeutic molecules. However, the studies are limited to in vivo an in vitro models, hence further studies are required to validate the complete potential of miRNA therapeutics. Long non-coding RNA (lncRNA) sponges, miRNA mimics, miRNA inhibitors, exosome-associated miRNAs, and several other molecules have been studied as miRNA-based therapeutics in PE. Thus, miRNAs are postulated to be potential therapeutic targets and miRNA-based therapeutics might pave the way for novel therapeutic approaches for PE.

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.

Hsa_circ_0002348 regulates trophoblast proliferation and apoptosis through miR-126-3p/BAK1 axis in preeclampsia

BACKGROUND

Preeclampsia is a common pregnancy complication characterized by high blood pressure and damage to organs. Abnormal placenta and vascular function can lead to preeclampsia. Accumulating evidence has suggested a potential link between circular RNAs (circRNAs) and preeclampsia. As a placenta and endothelial-expressed circRNA, hsa_circ_0002348, may be promising to be the novel molecular target for preeclampsia. However, the function and mechanism of hsa_circ_0002348 in preeclampsia has not been elucidated.

MATERIALS AND METHODS

An overlap analysis of two circRNA profiles from placenta and endothelial cells was used to identify a functionally unknown circRNA, hsa_circ_0002348. Quantitative real-time PCR (qRT-PCR) and in situ hybridization (ISH) were used to detect its expression in the trophoblast cells and placental tissues. The mouse model of lipopolysaccharide (LPS)-induced preeclampsia was established to determine the in vivo role of hsa_circ_0002348. RNA immunoprecipitation (RIP), Luciferase reporter assay, qRT-PCR, western blot, gain- and loss-of-function and rescue experiments were conducted to uncover the role of hsa_circ_0002348 and its interaction with miR-126-3p and BAK1 in regulating trophoblast proliferation and apoptosis. Fluorescence in situ hybridization (FISH) and Immunohistochemistry (IHC) were performed to examine the expression of miR-126-3p and BAK1 in mice and human placentas, respectively.

RESULTS

Hsa_circ_0002348 was significantly increased in the preeclampsia placentas, and positively correlated with the severity of preeclampsia patients' clinical manifestations. Its overexpression exacerbated preeclampsia-like features in the mouse model of LPS-induced preeclampsia. Functionally, hsa_circ_0002348 was found to inhibit trophoblast proliferation and promote trophoblast apoptosis. Mechanistically, hsa_circ_0002348, as an endogenous miR-126-3p sponge, upregulated the expression of BAK1. Additionally, both hsa_circ_0002348 knockdown and miR-126-3p overexpression enhanced the mammalian target of rapamycin (mTOR) and ERK1/2 signaling pathway.

CONCLUSIONS

Hsa_circ_0002348 might be a novel regulator of trophoblast proliferation and apoptosis through miR-126-3p/BAK1 axis in preeclampsia, which may serve as a potential target for detecting and treating preeclampsia.

Hsa_circ_0001326 inhibited the proliferation, migration, and invasion of trophoblast cells via miR-145-5p/TGFB2 axis

PROBLEM

Preeclampsia (PE) is an obstetric disease involving multiple systems, which account for maternal and fetal complications and increased mortality. Circular RNAs (circRNAs) were recently deemed to associate with the pathogenesis of PE. This study aims to clarify the correlation between circRNA hsa_circ_0001326 and PE and explore its biological function in PE.

METHOD OF STUDY

The expression of hsa_circ_0001326 in PE placentas was detected by real-time quantitative PCR (qRT-PCR). After overexpressing or inhibiting hsa_circ_0001326 in trophoblast cells, the cell growth, migration, and invasion were evaluated by Cell Counting Kit-8 (CCK-8) and transwell assays. Western blot assay was applied to detect the epithelial-mesenchymal transition (EMT) proteins, E-cadherin and Vimentin. Furthermore, a dual-luciferase reporter assay was applied to verify the binding sites of hsa_circ_0001326, miR-145-5p, and transforming growth factor beta 2 (TGFB2).

RESULTS

Hsa_circ_0001326 was found to be higher expressed in PE placentas than in normal placentas. Furthermore, hsa_circ_0001326 played a negative regulating role in trophoblast cell viability, migration, and invasion. Overexpression of hsa_circ_0001326 inhibited the viability, migration, and invasion of trophoblast cells, while inhibition of hsa_circ_0001326 showed opposite effects. Mechanistically, hsa_circ_0001326 sponged miR-145-5p to elevate TGFB2 expression in trophoblast cells.

CONCLUSION

This study provided evidence that the up-regulated hsa_circ_0001326 in PE restrained trophoblast cells proliferation, migration, and invasion by sponging miR-145-5p to elevate TGFB2 expression. Our results might provide a novel insight into the role of hsa_circ_0001326 in the pathogenesis 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.

Macrophage-derived exosomes regulate gastric cancer cell oxaliplatin resistance by wrapping circ 0008253

Oxaliplatin (OXA) is a first-line chemotherapy drug for gastric cancer. We aimed to investigate the effect of circ 0008253, contained in M2 polarized macrophage-derived exosomes, on OXA resistance of gastric carcinoma cells. Flow cytometry was performed to detect the differentiation of macrophages and cell apoptosis. Cell Counting Kit-8 assay was conducted to examine the cell viability. Transmission electron microscopy, Nanoparticle Tracking Analysis, Western bolt, and Immunofluorescence were carried out. Cell proliferation was detected with a colony formation experiment. Levels of CD206, Arg1, IL-10, and TGF-β were increased in M2 polarized macrophages. Cell viability was decreased gradually with the increase of time and OXA concentration. Apoptosis of gastric carcinoma cells was decreased after co-culture with M2-polarized macrophages. Exosomes isolated from M2-polarized macrophages (M2-Exos) could be co-located with gastric carcinoma cells. M2-Exos enhanced drug resistance, reduced apoptosis and OXA resistance. Bioinformatics analysis showed that circ 0008253 could be transferred from M2-Exos to gastric carcinoma cells. Overexpressing circ 0008253 increased cell viability, tumor size, and ABCG2 levels, decreased OXA sensitivity. Circ 0008253, contained in M2-Exos, was directly transferred from tumor-associated macrophage to gastric carcinoma cells, finally enhancing OXA resistance.

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.

Hypoxia-induced polarization of M2 macrophages and CCL5 secretion promotes the migration and invasion of trophoblasts

In the early stage of pregnancy, hypoxia in the placenta is of great significance to the migration and invasion of trophoblasts. In addition, changes to the polarity and activity of macrophages can affect embryo implantation, trophoblast migration and invasion, and vascular remodeling by affecting cytokine secretion. However, the mechanism of the effects of hypoxic conditions in the placenta on trophoblasts remains unknown. We used gene knockdown on macrophages, and drug treatment on trophoblasts, and cultured them under hypoxic and normoxic conditions. The cells were then subjected to wound healing assays, Transwell cell invasion experiments, quantitative real-time reverse transcription PCR, western blotting, and immunofluorescence. The polarization of macrophages in each group, the migration and invasion ability of trophoblasts, and changes to the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway were detected. Hypoxic conditions induce M2 polarization of macrophages. The conditioned medium from macrophages under hypoxic conditions increased the migration and invasion of trophoblasts, and enhanced the levels of phosphorylated (p)-PI3K and p-AKT in trophoblasts. After CCL5 knockdown in macrophages, the ability of conditioned medium from macrophages cultured under hypoxic conditions to promote the migration and invasion of trophoblasts was weakened significantly. The use of PI3K/AKT signaling pathway agonists could reverse the attenuation effect caused by CCL5 knockdown.

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.

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.

SNHG22 promotes migration and invasion of trophoblasts via miR-128-3p/PCDH11X axis and activates PI3K/Akt signaling pathway

OBJECTIVES

Long non-coding RNAs (LncRNAs) act as an indispensable role in the Preeclampsia (PE)-related trophoblast function, while its relationship with Small Nucleolar RNA Host Gene 22 (SNHG22) remains unknown. Hence, this study aimed to investigate the roles of lncRNA SNHG22 in the Preeclampsia (PE)-related trophoblasts function and the underlying mechanism.

METHOD

Normal placentas and placentas from PE patients were collected to detect the expression of lncRNA SNHG22. Then, trophoblasts HTR-8/Svneo and JEG-3 were purchased, cultured, and treated to investigate the roles of lncRNA SNHG22 on cell migration and invasion as well as its underlying regulatory mechanism.

RESULTS

The SNHG22 was downregulated in PE patients, and it was found that SNHG22 overexpression could drive migration and invasion of trophoblasts, while SNHG22 depletion exerted a suppressive effect. Mechanistically, SNHG22 was validated to regulate microRNA-128-3p (miR-128-3p), and Protocadherin 11 X-Linked (PCDH11X) was identified as the target gene of miR-128-3p. Furthermore, it was found that SNHG22 acted as a promoter in the migration and invasion of trophoblast cells in a miR-128-3p/PCDH11X dependent manner, and SNHG22 silencing weakened the activation of PCDH11X-mediated PI3K/Akt signaling pathways through inhibiting miR-128-3p, thereby preventing migration and invasion of trophoblasts.

CONCLUSION

SNHG22 acted as a driver in the migration and invasion of trophoblasts and may be considered a candidate for the amelioration of 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.

MiR-212-3p promotes proliferation and migration of trophoblast in fetal growth restriction by targeting placental growth factor

The purpose of this study was to evaluate the function and possible mechanism of miR-212-3p in fetal growth restriction (FGR) and to demonstrate the relationship between miR-212-3p and placental growth factor (PGF). First, we used qRT-PCR to detect the expression of miR-212-3p and PGF in placental tissues of normal delivery (HC group) and FGR, as well as in human trophoblast cell HTR-8/Svneo. The results revealed that miR-212-3p expression was significantly upregulated and PGF was significantly downregulated in placental tissue in the FGR group compared with the HC group. In addition, interference with miR-212-3p expression increased the proliferation, invasion, and migration of HTR-8/SVneo cells and decreased apoptosis of cells. Meanwhile, Western blot results showed that miR-212-3p expression downregulation promoted the phosphorylated protein expression of Phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT), which in turn activated the PI3K/AKT signaling pathway. And the results of dual luciferase reporter further showed that miR-212-3p could target PGF, and the expression of both was negatively correlated in FGR group tissues. In addition, downregulation of miR-212-3p expression reversed the inhibitory effect of PGF downregulation on HTR-8/SVneo cells. In conclusion, miR-212-3p can target and inhibit the PGF expression and regulate the PI3K/AKT signaling pathway to regulate trophoblast cell invasion, migration, proliferation and cell apoptosis. This provides a potential biomarker for the development of FGR.

Circular RNA circ_0111277 Serves as ceRNA, Targeting the miR-424-5p/NFAT5 Axis to Regulate the Proliferation, Migration, and Invasion of Trophoblast Cells in Preeclampsia

Preeclampsia is the main reason for maternal and fetal deaths during the second half of pregnancy. Trophoblast cells play a pivotal role in preeclampsia progression. Circular RNA (circRNA) circ_0111277 has been reported to be related to the development of trophoblast cells. This study is designed to explore the role and mechanism of circ_0111277 on trophoblast cell behavior in preeclampsia. Circ_0111277, microRNA-424-5p (miR-424-5p), and nuclear factor of activated T-cell 5 (NFAT5) levels were measured by real-time quantitative polymerase chain reaction (RT-qPCR). Cell viability, migration, invasion, and angiogenesis were measured by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay, transwell assay, tube formation assay, and wound healing assay. Protein levels of matrix metallopeptidase 2 (MMP2), vascular endothelial growth factor-A (VEGF-A), NFAT5, phospho-phosphatidylinositol 3 kinase (p-PI3K), PI3K, phospho-protein kinase B (p-AKT), and AKT were examined by western blot assay. The binding relationship between miR-424-5p and circ_0111277 or NFAT5 was predicted by circBank or starBase and then verified by a dual-luciferase reporter assay. Circ_0111277 and NFAT5 expression were increased in placenta tissues of preeclampsia patients, and miR-424-5p was decreased. Moreover, circ_0111277 knockdown could boost cell viability, migration, invasion, and angiogenesis in trophoblast cells. The mechanical analysis discovered that circ_0111277 acted as a sponge of miR-424-5p to regulate NFAT5 expression. Besides, circ_0111277 silencing promoted the PI3K/AKT signaling pathway in trophoblast cells. Circ_0111277 downregulation could facilitate cell growth and metastasis in trophoblast cells partly by regulating the miR-424-5p/NFAT5 axis, providing an underlying circRNA-targeted therapy for preeclampsia.

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.

Integrin β1 regulates proliferation, apoptosis, and migration of trophoblasts through activation of phosphoinositide 3 kinase/protein kinase B signaling

AIMS

Abnormal trophoblast invasion is one of the onsets of preeclampsia (PE). Studies found that integrin β1 (ITGB1) is closely related to PE, but the role of ITGB1 in the progression of trophoblast remained unclear. Therefore, we studied the functional role of ITGB1 in PE and its effects on trophoblast.

METHODS

ITGB1 expression in placenta tissues was determined by quantitative real-time polymerase chain reaction (qRT-PCR). The effects of transfection on HTR-8/SVneo cells were analyzed by qRT-PCR and western blotting. After cell transfection, colony formation assay, flow cytometry, wound healing assay, and transwell assay were performed to detect cell proliferation, apoptosis, migration, and invasion. Western blotting assay was used for determining phosphoinositide 3 kinase (PI3K) and protein kinase B (Akt) signaling pathway. After inhibiting PI3K/Akt pathway, apoptosis-regulated proteins were detected by western blotting, and the effects of inhibitor on the migration and invasion changes were examined.

RESULTS

ITGB1 was downregulated in placenta tissues from PE patients, as compared with normal. ITGB1 overexpression in HTR-8/SVneo cells enhanced cell proliferation, migration, and invasion, reduced cell apoptosis, and improved phosphorylation of PI3K and Akt. However, ITGB1 depletion resulted in an opposite effect to its overexpression. Inhibition of PI3K/Akt pathway completely blocked the effect of ITGB1 overexpression on cells, because we observed that apoptosis-regulated proteins were highly upregulated, and that cell migration and invasion were reduced.

CONCLUSION

ITGB1 regulated HTR-8/SVneo cell progression by activation of the PI3K/Akt pathway.