LncRNA TDRG1/miR-214-5p axis affects preeclampsia by modulating trophoblast cells

Long non-coding RNAs: a summary of their roles in placenta development and pathology†

Long non-coding RNAs are cellular transcripts that have ˃200 nucleotides in length and do not code for proteins. Due to their low expression levels, long non-coding RNAs were previously considered as mere transcriptional noise. However, current evidence indicates that they regulate a myriad of biological processes such as cell proliferation, invasion, and apoptosis. Hence, their expression patterns are crucial indicators of the physiological or pathological states of cells, tissues, and organs. The utilization of long non-coding RNAs as biomarkers and therapeutic targets for the clinical management of several diseases have been suggested. Gradually, long non-coding RNAs are gaining a substantial attention in the field of feto-maternal medicine. After embryo implantation, the interactions between the trophoblast cells from the embryo and the uterus of the mother facilitate placenta development and pregnancy progression. These processes are tightly regulated, and their impairments result in pregnancy pathologies such as miscarriage and preeclampsia. Accumulating evidence implicates long non-coding RNAs in these processes. Herein, we have summarized the roles of several long non-coding RNAs in human placenta development, have proposed some mechanisms by which they participate in physiological and pathological placentation, have revealed some knowledge deficits, and have recommended ideal experimental approaches that will facilitate the clarification of the mechanistic actions of each long non-coding RNA at the feto-maternal interface during healthy and pathological pregnancies.

lncRNA GHET1 regulates extravillous trophoblastic phenotype via EZH2/LSD1-mediated MT2A epigenetic suppression in pre-eclampsia

Pre-eclampsia (PE) is usually defined as new-onset hypertension with albuminuria or other organ damage. Herein, the role and mechanism of long noncoding RNA (lncRNA) gastric carcinoma high expressed transcript 1 (GHET1) during PE are investigated. Expression of GHET1 in PE pregnancies was evaluated using quantitative real-time polymerase chain reaction (qRT-PCR). Proliferation and cell cycle of extravillous trophoblasts were assessed by Cell Counting Kit-8 (CCK-8), colony formation, 5-Ethynyl-2'-deoxyuridine (EdU) assays, and flow cytometry, respectively. Migration, invasion, and network formation of trophoblasts were measured by wound healing, transwell system, and tube formation assays. RNA immunoprecipitation (RIP), RNA pull-down, and chromatin immunoprecipitation (ChIP) assays were used to confirm the molecular interaction. GHET1 was markedly decreased in the placenta of PE patients. GHET1 promoted the proliferation and cell cycle of extravillous trophoblasts, as well as migration, invasion, and network formation in vitro. Metallothionein 2A (MT2A) functioned as a downstream effector of GHET1, which was negatively correlated with GHET1 in PE. GHET1 directly bound with zeste 2 polycomb repressive complex 2/lysine-specific demethylase 1 (EZH2/LSD1). Knockdown of GHET1 reduced the occupancies of H3K27me3 and H3K4me2 in the MT2A promoter region by recruiting EZH2 and LSD1. MT2A knockdown reversed GHET1 inhibition mediated biological functions. GHET1 regulates extravillous trophoblastic phenotype via EZH2/LSD1-mediated MT2A epigenetic suppression in PE.

Identification of LncRNA-miRNA-mRNA ceRNA network in hypoxia-induced HTR-8/SVneo cells for preeclampsia

Preeclampsia (PE) is a common pregnancy complication, and placental hypoxia is one of its causes. We aimed to identify the transcriptional profile and construct a long non-coding RNAs (lncRNA)-centered competing endogenous RNAs (ceRNA) network in hypoxia-induced HTR8/SVneo cells. We used datasets from the GEO database to identify important pathways in PE. We performed microarray profiling and functional analysis to identify differentially expressed long non-coding RNAs (lncRNAs), differentially expressed profiles of microRNA (miRNAs), and differentially expressed profiles of messenger RNA (mRNAs) in hypoxia-induced HTR8/SVneo cells. The candidates were validated using quantitative reverse transcription polymerase chain reaction. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses were performed to understand the functional significance of differentially expressed genes. Finally, we constructed an lncRNA-centered ceRNA network. Several hub genes were validated both in placentas from PE and normal pregnancy, and in hypoxia-induced HTR8/SVneo cells. The hypoxic response pathway was involved in the pathophysiology of PE. Subsequently, we identified 536 differentially expressed profiles of lncRNAs (183 upregulated and 353 downregulated), 46 differentially expressed profiles of miRNAs (35 upregulated and 11 downregulated), and 2782 differentially expressed profiles of mRNAs (DEmRNAs) (1031 upregulated and 1751 downregulated) in hypoxia-induced HTR8/SVneo cells. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses revealed potential pathways affected by these genes, such as angiogenesis, the HIF-1 signaling pathway, and the PI3K-Akt signaling pathway. The ceRNA network comprised 35 lncRNAs, 11 miRNAs, 27 mRNAs, and 2 hub lncRNAs, which might play a vital role in placental functions and PE. Our results revealed the transcriptome profile and constructed an lncRNA-centered ceRNA network in hypoxia-induced HTR8/SVneo cells, thereby providing potential therapeutic targets for PE.

Elevated Expression of miRNA-181a-5p in Placenta Tissue of Preeclampsia

This study intends to assess miR-181a-5p expression profile in preeclampsia (PE). PE tissues from 30 patients and 30 normal pregnancy patients were obtained to measure miR-181a-5p level by RTPCR. Cell was transfected with miR-181a-5p mimics followed by analysis of cell migration by woundhealing assay, cell proliferation by CCK-8 assay as well as IGF2BP2 expression by RT-PCR and Bcl-2, Bax, caspase3, and Bcl-xl level by western blot. miR-181a-5p was significantly upregulated in PE patients. Mimics transfection significantly decreased cell migration and proliferation. Interestingly, miR-181a-5p bound to IGF2BP2 3′UTR. Further, miR-181a-5p upregulation decreased IGF2BP2 expression dose-dependently, upregulated the mRNA expression of Bax, caspase3 and Bcl-xl and downregulated Bcl-2. IGF2BP2 upregulated Bcl-2 and downregulated Bax and caspase3, which were reversed by miR-181a-5p. miRNA-181a-5p overexpression restrains placental trophoblast cells by down-regulation of IGF2BP2, thereby participating in PE pathogenesis.

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.

Long non-coding RNA PAXIP-AS1 promotes viability, invasion, and migration of HTR-8/SVneo cells through miR-210-3p/BDNF axis

OBJECTIVE

The aim of this research was to explore the role and potential mechanism of long non-coding RNA PAXIP-AS1 in preeclampsia.

METHODS

To investigate the effects of PAXIP-AS1 on cell viability, migration, and invasion. The miR-210-3p-targeted relationship with lncRNA PAXIP-AS1 or BDNF was verified.

RESULTS

PAXIP-AS1 was inversely correlated with miR-210-3p and BDNF was targeted by miR-210-3p. BDNF was positively correlated with PAXIP-AS1 in the serum of preeclampsia patients. The promotion effects of PAXIP-AS1 on cell viability, migration, and invasion were reversed by miR-210-3p up-regulation or BDNF knockdown in trophoblast cells.

CONCLUSION

PAXIP-AS1 promoted the viability, migration, and invasion of trophoblast cells by regulating the miR-210-3p/BDNF axis.

ceRNA Network and Functional Enrichment Analysis of Preeclampsia by Weighted Gene Coexpression Network Analysis

BACKGROUND

Preeclampsia (PE) is a multisystemic syndrome which has short- and long-term risk to mothers and children and has pluralistic etiology.

OBJECTIVE

This study is aimed at constructing a competitive endogenous RNA (ceRNA) network for pathways most related to PE using a data mining strategy based on weighted gene coexpression network analysis (WGCNA).

METHODS

We focused on pathways involving hypoxia, angiogenesis, and epithelial mesenchymal transition according to the gene set variation analysis (GSVA) scores. The gene sets of these three pathways were enriched by gene set enrichment analysis (GSEA). WGCNA was used to study the underlying molecular mechanisms of the three pathways in the pathogenesis of PE by analyzing the relationship among pathways and genes. The soft threshold power (β) and topological overlap matrix allowed us to obtain 15 modules, among which the red module was chosen for the downstream analysis. We chose 10 hub genes that satisfied ∣log2Fold Change | >2 and had a higher degree of connectivity within the module. These candidate genes were subsequently confirmed to have higher gene significance and module membership in the red module. Coexpression networks were established for the hub genes to unfold the connection between the genes in the red module and PE. Finally, ceRNA networks were constructed to further clarify the underlying molecular mechanism involved in the occurrence of PE. 56 circRNAs, 17 lncRNAs, and 20 miRNAs participated in the regulation of the hub genes. Coagulation factor II thrombin receptor (F2R) and lumican (LUM) were considered the most relevant genes, and ceRNA networks of them were constructed.

CONCLUSION

The microarray data mining process based on bioinformatics methods constructed lncRNA and miRNA networks for ten hub genes that were closely related to PE and focused on ceRNAs of F2R and LUM finally. The results of our study may provide insight into the mechanisms underlying PE occurrence.

Increased LINC00922 in preeclampsia regulates the proliferation, invasion, and migration of placental trophoblast cells

Background

Recent studies have shown that the abnormal expression of long-chain non-coding RNAs (lncRNAs) can significantly affect the biological function of trophoblast cells and lead to the occurrence of preeclampsia (PE). This study explores the expression of lncRNA LINC00922 in PE and its effect on the function of placental trophoblast cells, along with the corresponding molecular mechanism, providing a theoretical basis and molecular target for understanding the occurrence, early diagnosis, and targeted therapy of PE.

Methods

Fluorescence quantitative PCR was used to detect the expression of LINC00922 in 30 cases of PE tissues and normal tissues. The CCK-8 assay, clone formation experiment, and flow cytometry were used to detect the effects of LINC00922 knockdown or overexpression on the proliferation, colony formation, and cell cycle of HTR-8/SVneo placental trophoblast cells. The Transwell assay was used to detect the effects of LINC00922 knockdown or overexpression on the invasion and migration of HTR 8/SVneo cells, and western blot was used to detect the expression of cell cycle-related proteins and invasion and migration-related proteins.

Results

LINC00922 was highly expressed in PE tissues. Knockdown of LINC00922 significantly inhibited the proliferation, invasion, and migration of HTR-8/SVneo cells, along with colony formation and the ability to induce cell cycle arrest in the G0/G1 phase. However, overexpression of LINC00922 had the opposite effect. Knockdown or overexpression of LINC00922 significantly affected the expression of cell cycle-related proteins cyclin-dependent kinase 2 (CDK2), G1/S-specific cyclin-D1 (Cyclin D1), p21, proliferating cell nuclear antigen (PCNA), matrix metallopeptidase 9 (MMP-9), vimentin, and E-cadherin, but had no significant effect on the expression of matrix metallopeptidase 2 (MMP-2).

Conclusions

LINC00922 was highly expressed in PE, and functional experiments showed that LINC00922 could significantly affect the proliferation and invasion abilities of placental trophoblast cells, suggesting that LINC00922 may play an important role in the occurrence, early diagnosis, and treatment of PE.

lncRNA DANCR promotes the migration an invasion and of trophoblast cells through microRNA-214-5p in preeclampsia

Studies have shown that lncRNA DANCR is down-regulated in placental tissues of patients with preeclampsia (PE). The aim of this study was to explore the effect of lncRNA DANCR on trophoblast cells as well as its acting mechanism. We disrupted or overexpressed lncRNA DANCR in trophoblast cells HTR-8/SVneo and JEG-3 and detected the associated cellular functional changes by MTT, flow cytometry, Transwell experiment, and scratch experiment. The results showed that overexpression of lncRNA DANCR significantly increased the proliferation, invasion, migration, and EMT process of trophoblast cells. Interfering with lncRNA DANCR showed the opposite result. Further, the targeted interaction between lncRNA DANCR and miR-214-5p was confirmed by the dual-luciferase reporter gene assay. In addition, the expression of PI3K/AKT signaling pathway-related proteins was analyzed by Western blot. Overexpression of lncRNA DANCR can increase the phosphorylation of PI3K/AKT protein and activate this signaling pathway. In conclusion, the enforcing of lncRNA DANCR activates the activation of the PI3K/AKT pathway by down-regulating miR-214-5p, and promotes the migration and invasion of chorionic trophoblast cells. This provides a potential new target for PE therapy.

Increased expression of lncRNA SNHG7 promotes the cell viability, migration, and invasion in pre-eclampsia via modulating the miR-214-5p/TWIST1 axis

PURPOSE

This study is aimed to elucidate the molecular mechanism of lncRNA SNHG7 on pre-eclampsia (PE).

METHODS

The expression of SNHG7, miR-214-5p and TWIST1 in PE placental tissues was detected by qRT-PCR. The regulatory mechanism of SNHG7/miR-214-5p/TWIST1 axis on PE was determined using MTT, wound healing, transwell invasion, and western blot assays.

RESULTS

In PE pregnancies, SNHG7 and TWIST1 were decreased, while miR-214-5p was increased.The elevated miR-214-5p and decreased TWIST1 partly eliminated the promoting effects of SNHG7 up-regulation on the viability and metastasis of JEG-3 cells.

CONCLUSIONS

Up-regulated SNHG7 protects against PE through modulating the miR-214-5p/TWIST1 axi.

Roles of noncoding RNAs in preeclampsia

Preeclampsia (PE) is an idiopathic disease that occurs during pregnancy. It comprises multiple organ and system damage, and can seriously threaten the safety of the mother and infant throughout the perinatal period. As the pathogenesis of PE is unclear, there are few specific remedies. Currently, the only way to eliminate the clinical symptoms is to terminate the pregnancy. Although noncoding RNA (ncRNA) was once thought to be the "junk" of gene transcription, it is now known to be widely involved in pathological and physiological processes, including pregnancy-related disorders. Moreover, there is growing evidence that the unbalanced expression of specific ncRNA is involved in the pathogenesis of PE. In the present review, we summarize the expression patterns of ncRNAs, i.e., microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), and the functional mechanisms by which they affect the development of PE, and examine the clinical significance of ncRNAs as biomarkers for the diagnosis of PE. We also discuss the contributions made by genetic polymorphisms and epigenetic ncRNA regulation to PE. In the present review, we wish to explore and reinforce the clinical value of ncRNAs as noninvasive biomarkers of PE.

The Role of Long Non-Coding RNAs in Trophoblast Regulation in Preeclampsia and Intrauterine Growth Restriction

Preeclampsia (PE) and Intrauterine Growth Restriction (IUGR) are two pregnancy-specific placental disorders with high maternal, fetal, and neonatal morbidity and mortality rates worldwide. The identification biomarkers involved in the dysregulation of PE and IUGR are fundamental for developing new strategies for early detection and management of these pregnancy pathologies. Several studies have demonstrated the importance of long non-coding RNAs (lncRNAs) as essential regulators of many biological processes in cells and tissues, and the placenta is not an exception. In this review, we summarize the importance of lncRNAs in the regulation of trophoblasts during the development of PE and IUGR, and other placental disorders.

Recent Advances of MicroRNAs, Long Non-coding RNAs, and Circular RNAs in Preeclampsia

Preeclampsia is a clinical syndrome characterized by multiple-organ dysfunction, such as maternal hypertension and proteinuria, after 20 weeks of gestation. It is a common cause of fetal growth restriction, fetal malformation, and maternal death. At present, termination of pregnancy is the only way to prevent the development of the disease. Non-coding RNAs, including microRNAs, long non-coding RNAs, and circular RNAs, are involved in important pathological and physiological functions in life cycle activities including ontogeny, reproduction, apoptosis, and cell reprogramming, and are closely associated with human diseases. Accumulating evidence suggests that non-coding RNAs are involved in the pathogenesis of preeclampsia through regulation of various physiological functions. In this review, we discuss the current evidence of the pathogenesis of preeclampsia, introduce the types and biological functions of non-coding RNA, and summarize the roles of non-coding RNA in the pathophysiological development of preeclampsia from the perspectives of oxidative stress, hypoxia, angiogenesis, decidualization, trophoblast invasion and proliferation, immune regulation, and inflammation. Finally, we briefly discuss the potential clinical application and future prospects of non-coding RNA as a biomarker for the diagnosis of preeclampsia.

Long Non-Coding RNA Nuclear-Enriched Abundant Transcript 1 (NEAT1) Represses Proliferation of Trophoblast Cells in Rats with Preeclampsia via the MicroRNA-373/FLT1 Axis

Background

Preeclampsia (PE) remains one of the primary causes of maternal morbidity and mortality worldwide. This study was designed to investigate the relevance of long non-coding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) and downstream molecules in trophoblast cell proliferation and apoptosis.

Material/Methods

NEAT1 expression in the placental tissues of rats with PE was analyzed by reverse transcriptionquantitative polymerase chain reaction. The role of NEAT in trophoblast cell proliferation, migration, invasion, and apoptosis was assessed by transfecting pcDNA-NEAT1 and siRNA-NEAT1 into trophoblast cells. The microRNA (miRNA) binding to NEAT1 and the genes targeted by the screened miRNAs were predicted by Starbase, and the mechanism of action of NEAT1 in PE was further investigated.

Results

The expression of NEAT1 lncRNA was markedly higher in placental samples of PE than control rats. Ectopic expression of NEAT1 repressed trophoblast cell proliferation, migration, invasion, and colony formation, but facilitated cell apoptosis, whereas NEAT1 downregulation resulted in the opposite effects. NEAT1 was found to act as a molecular sponge for miR-373, regulating Fms-like tyrosine kinase-1 (FLT-1) to modulate PE development.

Conclusions

NEAT1 may contribute to PE development by regulating trophoblast cell proliferation and apoptosis. These findings may provide a new perspective for understanding the etiology and pathogenesis of PE.