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

Serum lncRNAs TUG1, H19, and NEAT1 and their target miR-29b/SLC3A1 axis as possible biomarkers of preeclampsia: Potential clinical insights

To date, the epigenetic signature of preeclampsia (PE) is not completely deciphered. Oxidative stress-responsive long non-coding RNAs (lncRNAs) are deregulated in preeclamptic placenta; however, their circulating profiles and diagnostic abilities are still unexplored. We investigated serum redox-sensitive lncRNAs TUG1, H19, and NEAT1, and their target miR-29b/cystine/neutral/dibasic amino acids transporter solute carrier family 3, member 1 (SLC3A1) as potential non-invasive biomarkers of PE risk, onset, and severity. We recruited 82 patients with PE and 78 healthy pregnant women. We classified PE patients into early-onset (EOPE) and late-onset (LOPE) subgroups at a cut-off 34 gestational weeks and into severe and mild PE subgroups by blood pressure and proteinuria criteria. Bioinformatics analysis was employed to select lncRNAs/microRNA/target gene interactions. Serum H19, NEAT1, and SLC3A1 mRNA expression were reduced, meanwhile miR-29b levels were elevated, whereas there was no significant difference in TUG1 levels between PE patients and healthy pregnancies. Serum H19 levels were lower, whereas miR-29b levels were higher in EOPE versus LOPE. Serum miR-29b and H19 levels were higher in severe versus mild PE. ROC analysis identified serum H19, NEAT1, miR-29b, and SLC3A1 as potential diagnostic markers, with H19 (AUC = 0.818, 95%CI = 0.744-0.894) and miR-29b (AUC = 0.82, 95%CI = 0.755-0.885) were superior discriminators. Only H19 and miR-29b discriminated EOPE and severe PE cases. In multivariate logistic analysis, miR-29b and H19 were associated with EOPE, using maternal age and gestational age as covariates, while miR-29b was associated with severe PE, using maternal age as covariate. Studied markers were correlated with clinical and ultrasound data in the overall PE group. Serum H19 and TUG1 were negatively correlated with albuminuria in EOPE and LOPE, respectively. NEAT1 and SLC3A1 were correlated with ultrasound data in EOPE. Likewise, TUG1, miR-29b, and SLC3A1 showed significant correlations with ultrasound data in LOPE. Conclusively, this study configures SLC3A1 expression as a novel potential serum biomarker of PE and advocates serum H19 and miR-29b as biomarkers of EOPE and miR-29b as a biomarker of PE severity.

Non-coding RNA regulates the immune microenvironment in recurrent spontaneous abortion (RSA): new insights into immune mechanisms†

Recurrent spontaneous abortion (RSA) has various causes, including chromosomal abnormalities, prethrombotic state, and abnormal uterine anatomical factors. However, the pathogenesis of RSA is still unclear. Surprisingly, non-coding RNA can stably express at the maternal-fetal interface and regulate immune cells' proliferation, apoptosis, invasion, metastasis, and angiogenesis. Accumulating evidence suggests that the competing endogenous RNA (ceRNA) regulatory network between non-coding RNAs complicates RSA's pathological process and maybe a new starting point for exploring RSA. In this review, we mainly discuss the regulatory network and potential significance of non-coding RNA in the immune microenvironment of RSA patients. In addition, the cellular interactions of non-coding RNA transported through vesicles were introduced from aspects of trophoblast function and immune regulation. Finally, we analyze previous studies and further discuss that the stable expression of non-coding RNA may be used as a biomarker of some disease states and a prediction target of RSA.

Elevated high-mannose N-glycans hamper endometrial decidualization

Decidualization of endometrial stromal cells is a hallmark of endometrial receptivity for embryo implantation, and dysfunctional decidualization is associated with pregnancy failure. Protein glycosylation is an important posttranslational modification that affects the structure and function of glycoproteins. Our results showed that high-mannose epitopes were elevated in the decidual tissues of miscarriage patients compared with early pregnant women by Lectin microarray. Furthermore, the level of mannosyl-oligosaccharide α-1,2 mannosidase IA (MAN1A1), a key enzyme for high-mannose glycan biosynthesis, was decreased in the decidual tissues of miscarriage patients. Screening of lncRNAs showed that lncNEAT1 level was increased in the serum and decidua of miscarriage patients, and negatively correlated with MAN1A1 expression. The results also revealed that specific binding of lncNEAT1 with nucleophosmin (NPM1)-SP1 transcription complex inhibited MAN1A1 expression and hampered endometrial decidualization and embryo implantation potential. The study suggests the new insights into the function of high-mannose glycans/MAN1A1 modification during endometrial decidualization.

Functional Roles of lncRNAs in Recurrent Pregnancy Loss: A Review Study

Recurrent pregnancy loss (RPL) or recurrent miscarriage is the failure of pregnancy before 20-24 weeks that influences around 2-5% of couples. Several genetic, immunological, environmental and physical factors may influence RPL. Although various traditional methods have been used to treat post-implantation failures, identifying the mechanisms underlying RPL may improve an effective treatment. Recent evidence suggested that gene expression alterations presented essential roles in the occurrence of RPL. It has been found that long non-coding RNAs (lncRNAs) play functional roles in pregnancy pathologies, such as recurrent miscarriage. lncRNAs can function as dynamic scaffolds, modulate chromatin function, guide and bind to microRNAs (miRNAs) or transcription factors. lncRNAs, by targeting various miRNAs and mRNAs, play essential roles in the progression or suppression of RPL. Therefore, targeting lncRNAs and their downstream targets might be a suitable strategy for diagnosis and treatment of RPL. In this review, we summarized emerging roles of several lncRNAs in stimulation or suppression of RPL.

Role of microRNAs in trophoblast invasion and spiral artery remodeling: Implications for preeclampsia

It is now well-established that microRNAs (miRNAs) are important regulators of gene expression. The role of miRNAs in placental development and trophoblast function is constantly expanding. Trophoblast invasion and their ability to remodel uterine spiral arteries are essential for proper placental development and successful pregnancy outcome. Many miRNAs are reported to be dysregulated in pregnancy complications, especially preeclampsia and they exert various regulatory effects on trophoblasts. In this review, we provide a brief overview of miRNA biogenesis and their mechanism of action, as well as of trophoblasts differentiation, invasion and spiral artery remodeling. We then discuss the role of miRNAs in trophoblasts invasion and spiral artery remodeling, focusing on miRNAs that have been thoroughly investigated, especially using multiple model systems. We also discuss the potential role of miRNAs in the pathogenesis of preeclampsia.

Long Non-Coding RNA ZEB2-AS1 Augments Activity of Trophoblast Cells and Prevents the Development of Recurrent Spontaneous Abortion in Mice Through EZH2-Mediated CST3 Inhibition

Recurrent spontaneous abortion (RSA) is the most common complication of pregnancy where reduced invasion of trophoblasts plays a major role. This work aimed to explore the effect of abnormally expressed long non-coding RNA (lncRNA) ZEB2-AS1 on the occurrence of RSA. Differentially expressed lncRNAs in trophoblast cells between healthy controls and patients with RSA were screened using the GEO database. Female CBA/J mice were allowed to mate with male DBA/2 mice to establish inbred mice with RSA. ZEB2-AS1 was poorly expressed in placental tissues and trophoblast cells in the condition of RSA. ZEB2-AS1 upregulation augmented proliferation, migration, and invasion of trophoblast cells in vitro. ZEB2-AS1 negatively regulated cystatin C (CST3) expression. Further overexpression of CST3 blocked the activity of trophoblast cells. ZEB2-AS1 recruited enhancer of EZH2 to the promoter region of CST3, which increased H3K27me3 modification to suppress CST3 expression. In vivo, overexpression of ZEB2-AS1 reduced embryo resorption rate and increased the weights of fetuses and placentas in mice with RSA. However, the protective roles of ZEB2-AS1 were blocked upon artificial silencing of EZH2 or upregulation of CST3. Taken together, this study demonstrates that ZEB2-AS1 enhances activity of trophoblast cells and prevents RSA development through reducing CST3 expression in an EZH2-dependent manner.

LncRNA NEAT1 Promotes TLR4 Expression to Regulate Lipopolysaccharide-Induced Trophoblastic Cell Pyroptosis as a Molecular Sponge of miR-302b-3p

Pyroptosis is an inflammation-triggered cell death caused by certain inflammasomes, and long non-coding RNAs (lncRNAs) are related to cell pyroptosis. This study evaluated the mechanism of lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) on lipopolysaccharide (LPS)-induced trophoblastic cells pyroptosis. HTR-8/Svneo trophoblastic cells were treated with LPS. The expression of lncRNA NEAT1 was decreased using siRNAs, followed by the evaluation of cell proliferation, Caspase-1 activity, levels of Cleaved Caspase-1 and gasdermin D-N, and the concentrations of Interleukin (IL)-1β and IL-18. We found that LPS promoted the pyroptosis of HTR-8/Svneo cells, and lncRNA NEAT1 was highly expressed in LPS-treated HTR-8/Svneo cells while silencing lncRNA NEAT1 inhibited LPS-induced trophoblastic cells pyroptosis. The subcellular localization of lncRNA NEAT1 was detected. Dual-luciferase gene experiment and RNA pull-down assay detected that lncRNA NEAT1 bound to miR-302b-3p and could inhibit miR-302b-3p, and toll-like receptor 4 (TLR4) was the target gene of miR-302b-3p. Then, a joint experiment was designed for detection, which found that miR-302b-3p downregulation partially reversed the inhibition of silencing lncRNA NEAT1 on LPS-induced trophoblastic cells pyroptosis and overexpression of TLR4 annulled the inhibition of silencing lncRNA NEAT1 on LPS-induced trophoblastic cells pyroptosis. Therefore, lncRNA NEAT1 promoted the transcription of TLR4 by competitively binding to miR-302b-3p, thus promoting LPS-induced trophoblastic cells pyroptosis.

Nampt promotes fibroblast extracellular matrix degradation in stress urinary incontinence by inhibiting autophagy

Stress urinary incontinence (SUI) is defined as involuntary urinary leakage happening in exertion. Nicotinamide phosphoribosyltransferase (Nampt) is seldom researched in the pathogenesis of SUI. Accordingly, the current study set out to elucidate the role of Nampt in SUI progression. Firstly, we determined Nampt expression patterns in SUI patients and rat models. In addition, fibroblasts were obtained from the anterior vaginal wall tissues of non-SUI patients and subjected to treatment with different concentrations of interleukin-1β (IL-1β), followed by quantification of Nampt expressions in fibroblasts. Subsequently, an appropriate concentration of IL-1β was selected to treat anterior vaginal wall fibroblasts. Nampt was further silenced in IL-1β-treated fibroblasts to assess the role of Nampt in autophagy and extracellular matrix (ECM) degradation. Lastly, functional rescue assays were carried out to inhibit autophagy and evaluate the role of autophagy in the mechanism of Nampt modulating IL-1β-treated fibroblast ECM degradation. It was found that Nampt was highly-expressed in SUI patients and rat models and IL-1β-treated fibroblasts. On the other hand, Nampt silencing was found to suppress ECM degradation and promote SUI fibroblast autophagy. Additionally, inhibition of autophagy attenuated the inhibitory effects of Nampt silencing on SUI fibroblast ECM degradation. Collectively, our findings revealed that Nampt was over-expressed in SUI, whereas Nampt silencing enhanced SUI fibroblast autophagy, and thereby inhibited ECM degradation.

Silencing of long non-coding RNA NEAT1 improves Treg/Th17 imbalance in preeclampsia via the miR-485-5p/AIM2 axis

T-regulatory (Treg)/T-helper 17 (Th17) imbalance is associated with preeclampsia (PE). Herein, we aimed to explore the effect and mechanism of lncRNA NEAT1 on the Treg/Th17 balance. The levels of nuclear enriched abundant transcript 1 (NEAT1), miR-485-5p, and absent in melanoma 2 (AIM2) in CD4⁺ T cells were determined using real-time quantitative polymerase chain reaction (RT-qPCR). Treg and Th17 cells were examined using flow cytometry. The relationship between miR-485-5p and NEAT1 or AIM2 was assessed using a dual-luciferase reporter assay. Pearson’s correlation coefficient was used to analyze the correlation. All the data indicated that NEAT1 was upregulated in PE. The number of Treg cells decreased and was negatively related to NEAT1, whereas the number of Th17 cells increased and was positively related to NEAT1 in PE. Knockdown of NEAT1 increased the Treg cells and Treg/Th17 but decreased Th17 cells. Furthermore, NEAT1 sponges miR-485-5p to suppress the target AIM2 levels. Inhibition of miR-485-5p or upregulation of AIM2 abrogated the effect on Treg/Th17 balance induced by knockdown of NEAT1. In conclusion, silencing of NEAT1 promoted Treg/Th17 balance via the miR-485-5p/AIM2 axis in PE, suggesting that NEAT1 is a potential target for the treatment of PE.

Non-Coding RNAs Regulate Placental Trophoblast Function and Participate in Recurrent Abortion

Recurrent spontaneous abortion (RSA) is a serious pregnancy complication with an increasing clinical incidence. The various causes of recurrent abortion are complicated. Developments in genetics, immunology, and cell biology have identified important roles of non-coding RNAs (ncRNAs) in the occurrence and progress of recurrent abortion. NcRNAs can affect the growth, migration, and invasion of placental trophoblasts by regulating cell processes such as the cell cycle, apoptosis, and epithelial-mesenchymal transformation. Therefore, their abnormal expression might lead to the occurrence and development of RSA. NcRNAs include small nuclear RNA (snRNA), small nucleolar RNA (snoRNA), ribosomal RNA (rRNA), transfer, RNA (tRNA), circular RNA (cRNA), and Piwi-interacting RNA (piRNA). In this review, we discuss recent research that focused on the function and mechanism of microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNA (circRNA) in regulating placental trophoblasts. The use of ncRNAs as potential diagnostic and predictive biomarkers in RSA is also discussed to provide future research insights.