MiR-137 Restricts the Viability and Migration of HTR-8/SVneo Cells by Downregulating FNDC5 in Gestational Diabetes Mellitus

Hsa_circ_0006260 Mediates Trophoblast Function by Fibronectin Type III Domains Containing Protein 5 via Interacting with miR-770-5p

A series of studies have confirmed the relationship between circular RNAs (circRNAs) and metabolic diseases. Hsa_circ_0006260 has been reported to be lowly expressed in the placenta of gestational diabetes mellitus (GDM) patients, but the underlying mechanism and its biological functions remain obscure. Placental tissues were collected from 37 pregnant women with normal glucose tolerance (NGT) and 37 pregnant women with GDM. Expression changes of hsa_circ_0006260 in placentas and high glucose (HG)-stimulated HTR-8/SVneo cells were detected using real-time quantitative polymerase chain reaction. Cell viability and migration were determined by cell counting and transwell assays, respectively. Measurement of cytokines was done by enzyme-linked immunosorbent assay. Cell apoptosis was estimated by flow cytometry assay. The molecular mechanisms were identified using dual-luciferase reporter and RNA-binding protein immunoprecipitation assays. Hsa_circ_0006260 expression was remarkably lowered in GDM patient-derived placentas and HG-stimulated HTR-8/SVneo cells. Functionally, hsa_circ_0006260 overexpression weakened HG-mediated repression of HTR-8/SVneo cell viability and migration, as well as promotion of HTR-8/SVneo cell inflammatory response and apoptosis. Mechanistically, hsa_circ_0006260 functioned as a miR-770-5p decoy to mediate fibronectin type III domains containing protein 5 (FNDC5) expression. Ectopic expression of miR-770-5p weakened hsa_circ_0006260 overexpression-mediated repression of HG-induced HTR-8/SVneo cell dysfunction. Also, FNDC5 knockdown lessened miR-770-5p overexpression-mediated promotion of HG-induced HTR-8/SVneo cell dysfunction. Our findings manifested a novel mechanism by which hsa_circ_0006260 could lower HG-induced HTR-8/SVneo cell dysfunction by upregulating FNDC5 via binding to miR-770-5p, which shed new light on circRNA mediated GDM pathogenesis.

METTL14-mediated lncRNA XIST silencing alleviates GDM progression by facilitating trophoblast cell proliferation and migration via the miR-497-5p/FOXO1 axis

Gestational diabetes mellitus (GDM), a prevalent complication during the gestation period, has been linked to impaired proliferation and migration of trophoblasts causing placental maldevelopment. We previously found that lncRNA X-inactive specific transcript (XIST) played an essential role in GDM progression. Here, we investigated the precise biological functions as well as the upstream and downstream regulatory mechanisms of XIST in GDM. We found that XIST and forkhead box O1 (FOXO1) were conspicuously upregulated and miR-497-5p and methyltransferase-like 14 (METTL14) were downregulated in the placentas of GDM patients. XIST silencing facilitated proliferation and migration and inhibited cell apoptosis and cell cycle arrest in HG-cultured HTR8/SVneo cells. METTL14 inhibited XIST expression through m6A methylation modification. XIST overexpression abrogated the positive effect of METTL14 overexpression on HG-cultured HTR8/SVneo cell progression. MiR-497-5p and FOXO1 are downstream regulatory genes of XIST in HTR8/SVneo cells. Reverse experiments illustrated that XIST mediated HTR8/SVneo cell functions by regulating the miR-497-5p/FOXO1 axis. Additionally, XIST silencing augmented glucose tolerance and alleviated fetal detrimental changes in GDM rats. To conclude, METTL14-mediated XIST silencing facilitated proliferation and migration and inhibited cell apoptosis and cell cycle arrest in HG-cultured HTR8/SVneo cells via the miR-497-5p/FOXO1 axis, thereby alleviating GDM progression in rats.

Expression of microRNAs in patients with gestational diabetes mellitus: a systematic review and meta-analysis

BACKGROUND

MicroRNAs (miRNA) are noncoding RNAs that play a central role in governing various physiological and pathological processes. There are few studies on miRNA involvement in gestational diabetes mellitus (GDM). In this study, we performed a meta-analysis of the miRNA expression profiling from GDM patients.

METHODS

Guided by the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols, we performed a systematic search of the PubMed, Cochrane Library, and EMBASE databases from inception to December 20, 2021, to retrieve the original research studies. All the relevant data were retrieved, analyzed, and summarized.

RESULTS

Six studies (252 GDM cases and 309 controls) were included and analyzed. The six studies reported the expressions of 21 miRNAs in GDM cases. Of the 21 miRNAs, 12 miRNAs were found to be upregulated, and two were downregulated. The top three most consistently reported upregulated miRNAs were miR-16-5p (mean differences of fold change are 1.25, 95% CI = 0.04-2.46, P = 0.040), miR-19a-3p (mean differences of fold change are 2.90, 95% CI = 1.45-4.35, P = 0.001), and miR-19b-3p (mean differences of fold change are 3.10, 95% CI = 0.94-5.25, P = 0.005). miR-155-5p and miR-21-3p were found to be downregulated.

CONCLUSIONS

The results indicate that several miRNAs may be used as markers for diabetes gestational diabetes mellitus. In the future, more studies are needed to validate the findings of our study.

Hyperglycemia disturbs trophoblast functions and subsequently leads to failure of uterine spiral artery remodeling

Uterine spiral artery remodeling is necessary for fetal growth and development as well as pregnancy outcomes. During remodeling, trophoblasts invade the arteries, replace the endothelium and disrupt the vascular smooth muscle, and are strictly regulated by the local microenvironment. Elevated glucose levels at the fetal-maternal interface are associated with disorganized placental villi and poor placental blood flow. Hyperglycemia disturbs trophoblast proliferation and invasion via inhibiting the epithelial-mesenchymal transition, altering the protein expression of related proteases (MMP9, MMP2, and uPA) and angiogenic factors (VEGF, PIGF). Besides, hyperglycemia influences the cellular crosstalk between immune cells, trophoblast, and vascular cells, leading to the failure of spiral artery remodeling. This review provides insight into molecular mechanisms and signaling pathways of hyperglycemia that influence trophoblast functions and uterine spiral artery remodeling.

Circ_FOXP1 promotes the growth and survival of high glucose-treated human trophoblast cells through the regulation of miR-508-3p/SMAD family member 2 pathway

Gestational diabetes mellitus (GDM) is a health risk for pregnant women and infants. Emerging evidence suggests that the deregulation of circular RNAs (circRNAs) is associated with the progression of this disorder. The objective of this study was to investigate the role of circ_FOXP1 in GDM. Cell models of GDM were established by treating human trophoblast cells with high glucose (HG). The expression of circ_FOXP1, miR-508-3p and SMAD family member 2 (SMAD2) mRNA was detected by quantitative real-time PCR (qPCR). Cell proliferation was assessed by EdU assay and MTT assay, and cell cycle and cell apoptosis were determined by flow cytometry assay. The protein levels of proliferation- and apoptosis-related markers and SMAD2 were measured by western blot. The relationship between miR-508-3p and circ_FOXP1 or SMAD2 was validated by dual-luciferase reporter assay or pull-down assay. The expression of circ_FOXP1 was downregulated in HG-treated HTR-8/SVneo cells. Circ_FOXP1 overexpression promoted HG-inhibited HTR-8/SVneo cell proliferation and suppressed HG-induced HTR-8/SVneo cell cycle arrest and apoptosis. Circ_FOXP1 positively regulated the expression of SMAD2 by targeting miR-508-3p. MiR-508-3p was overexpressed in HG-treated HTR-8/SVneo cells, and its overexpression reversed the effects of circ_FOXP1 overexpression. MiR-508-3p inhibition also alleviated HG-induced HTR-8/SVneo cell injuries, while the knockdown of SMAD2 abolished these effects. Collectively, circ_FOXP1 promotes the growth and survival of HG-treated human trophoblast cells through the miR-508-3p/SMAD2 pathway, hinting that circ_FOXP1 was involved in GDM progression.

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.

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.

LncRNA OIP5-AS1 Signatures as a Biomarker of Gestational Diabetes Mellitus and a Regulator on Trophoblast Cells

OBJECTIVES

Gestational diabetes mellitus (GDM) is a common disorder in pregnant women. Long noncoding RNA (lncRNA) is a fundamental mediator in the pathogenesis of GDM. The study aimed to detect the clinical importance of lncRNA OIP5-AS1 and its underlying regulation on trophoblast cells.

DESIGN

The expression of OIP5-AS1 and miR-137-3p was assessed by the quantitative real-time PCR technique. The prognostic effect of OIP5-AS1 was analyzed by the receiver operating characteristic curve. The influences of OIP5-AS1 on cells were indicated by cell counting kit-8, transwell experiments, and flow cytometry. Luciferase activity assay was used to identify the target relationships among OIP5-AS1, miR-137-3p, and EZH2.

PARTICIPANTS

A total of 75 pregnant women with GDM who were treated in the Dongying People's Hospital were selected as the GDM group. Besides, 72 pregnant women with non-GDM who underwent physical examination in the same hospital were selected as the control group.

RESULTS

Decreased expression of OIP5-AS1 was confirmed in GDM patients, and the level of OIP5-AS1 could be used as a basis for evaluating GDM patients. Upregulation of OIP5-AS1 ameliorated the viability, migration, invasion, and apoptosis of HG-stimulated HTR-8/SVneo cells by sponging miR-137-3p. EZH2 was a direct target of miR-137-3p.

CONCLUSIONS

OIP5-AS1 level decreased in women with GDM. OIP5-AS1 appeared to help separating GDM patients from healthy pregnant women. The OIP5-AS1/miR-137-3p/EZH2 pathway could exert its function on HG-induced HTR-8/SVneo models.

Association between maternal pregestational glucose level and adverse pregnancy outcomes: a population-based retrospective cohort study

OBJECTIVE

To investigate the association between maternal pregestational blood glucose level and adverse pregnancy outcomes.

DESIGN

Retrospective cohort study.

SETTING

This study was conducted in the Chongqing Municipality of China between April 2010 and December 2016.

PARTICIPANTS

A total of 60 222 women (60 360 pregnancies) from all 39 counties of Chongqing who participated in the National Free Preconception Health Examination Project and had pregnancy outcomes were included.

PRIMARY OUTCOME MEASURES

Adverse pregnancy outcomes included spontaneous abortion, induced abortion or labour due to medical reasons, stillbirth, preterm birth (PTB), macrosomia, large for gestational age, low birth weight (LBW) and small for gestational age.

RESULTS

Of the 60 360 pregnancies, rates of hypoglycaemic, normoglycaemia, impaired fasting glycaemia (IFG) and diabetic hyperglycaemic before conception were 5.06%, 89.30%, 4.59% and 1.05%, respectively. Compared with women with normoglycaemia, women with pregestational glucose at the diabetic level (≥7.0 mmol/L) might have a higher rate of macrosomia (6.18% vs 4.16%), whereas pregestational IFG seemed to be associated with reduced risks of many adverse outcomes, including spontaneous abortion, induced abortion due to medical reasons, PTB and LBW. After adjusting for potential confounders, pregestational diabetic hyperglycaemic was remained to be significantly associated with an increased risk of macrosomia (adjusted risk ratio 1.49, 95% CI 1.07 to 2.09). Abnormal maternal glucose levels before pregnancy (either hypoglycaemic or hyperglycaemic) seemed to have no significant negative effect on spontaneous abortion or induced abortion due to medical reasons.

CONCLUSION

Although without overt diabetes mellitus, women with once diabetic fasting glucose level during their preconception examinations could be associated with an increased risk for macrosomia. Uniform guidelines are needed for maternal blood glucose management during pre-pregnancy care to improve pregnancy outcomes.

MiR-34b-3p Impaired HUVECs Viability and Migration via Targeting PDK1 in an In Vitro Model of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) leads to poor pregnancy outcomes. The methods for GDM early diagnosis and treatment are still unknown. This study aimed to investigate the expression and diagnostic potential of miR-34b-3p in GDM patients and further analyzed the effects of miR-34b-3p on HUVECs viability and migration. The expression of miR-34b-3p was detected in HUVECs of GDM and normal pregnant women by qRT-PCR. Then the HUVECs were isolated from normal pregnant women. High glucose (HG) was used to treat the HUVECs to mimic the GDM in vitro. The cell viability and migration were determined by MTT, wound healing assay, and transwell assay. The interaction between miR-34b-3p and PDK1 was evaluated by luciferase activity assay. Our results showed that miR-34b-3p was up-regulated in HUVECs of GDM patients. Then the HUVECs were isolated from normal pregnant women and they were treated with HG to mimic the GDM in vitro. Interestingly, knockdown of miR-34b-3p restored the impairment of HG treatment-induced effects in HUVECs. More importantly, PDK1 was proved to be a potential target of miR-34b-3p. Finally, the rescue experiments confirmed that miR-34b-3p impaired cell viability and migration ability in HUVECs by targeting PDK1. These findings concluded that miR-34b-3p impaired HUVECs viability and migration in GDM by targeting PDK1, which might provide a novel perspective for the pathogenesis and underlying therapeutic target for GDM.

miR-377 inhibition enhances the survival of trophoblast cells via upregulation of FNDC5 in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a metabolic dysregulation closely related to both obesity and type 2 diabetes; however, the molecular mechanism underlying GDM is still unclear. The purpose of this study was to investigate the effects of microRNA-377 (miR-377-3p) and fibronectin type III domain containing 5 (FNDC5) in regulating the cell growth of trophoblasts under high glucose (HG) conditions during the development of GDM. Serum miR-377-3p was upregulated and positively correlated with fasting blood glucose level in GDM patients. miR-377-3p downregulation increased the cell vitality and suppressed the cell apoptosis of HG-treated HTR-8/SVneo and BeWo cells. Using TargetScan prediction, luciferase assay, and western blot, it was found that miR-377-3p could target FNDC5 and suppress its expression. However, FNDC5 downregulation abolished the effect of miR-377-3p inhibitor in HTR-8/SVneo cells. Together, miR-377 is a potential target for GDM biomarker, which promotes cell growth and suppresses cell apoptosis, partly through the upregulation of FNDC5.

MicroRNA-1323 serves as a biomarker in gestational diabetes mellitus and aggravates high glucose-induced inhibition of trophoblast cell viability by suppressing TP53INP1

Gestational diabetes mellitus (GDM) leads to poor pregnancy outcomes, and microRNAs (miRNAs/miRs) have been suggested to be associated with GDM, but the pathological mechanisms remain unclear. The present study aimed to investigate the diagnostic value of miR-1323 in GDM patients and its effects on trophoblast cell viability. Additionally, the present study investigated the correlation between miR-1323 and TP53INP1 to understand the pathological mechanism of GDM progression. Reverse transcription-quantitative polymerase chain reaction was used to detect the miR-1323 expression and TP53INP1 mRNA expression. The diagnostic value of serum miR-1323 was evaluated by receiver operating characteristic analysis. HTR-8/SVneo and BeWo cells were treated with high glucose (HG) to construct cell models of GDM, and trophoblast cell viability was assessed using an MTT assay. The protein expression of TP53INP1 was detected by western blot analysis. The correlation between miR-1323 and TP53INP1 was investigated by luciferase reporter assay. The miR-1323 expression was increased in patients with GDM, which had relatively high diagnostic accuracy for GDM screening and was positively correlated with fasting blood glucose in patients GDM. HG upregulated the miR-1323 expression and inhibited trophoblast cell viability. Overexpression of miR-1323 significantly inhibited the viability of HG-induced trophoblast cells. TP53INP1, a target gene of miR-1323, was negatively correlated with miR-1323. TP53INP1 overexpression reversed the inhibitory effect of miR-1323 overexpression on the viability of HG-treated trophoblast cells. Increased levels of serum miR-1323 may be a diagnostic biomarker for GDM. Additionally, miR-1323 may inhibit trophoblast cell viability by inhibiting TP53INP1, suggesting that it may be a potential therapeutic target for GDM.

Aberrantly Expressed Non-Coding RNAs in the Placenta and Their Role in the Pathophysiology of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM), one of the most common complications during pregnancy, is associated with a high risk of short- and long-term adverse effects on the mother and offspring. Placenta-derived hormones and cytokines aggravate maternal insulin resistance (IR) during pregnancy, which in turn contribute to GDM. The hyperglycemia and IR in GDM result in aberrant placental structure and function adversely affecting fetal growth and well-being. Therefore, it is reasonable to assume that structural and functional alterations in the placenta contribute to the pathogenesis of GDM and GDM-related complications. Increasing evidence suggests that multiple non-coding RNAs (ncRNAs), including microRNAs, long non-coding RNAs, and circular RNAs, are dysregulated in placentas of patients with GDM and linked to abnormal placental structure, metabolism, and function. Manipulation of ncRNA expression led to some key pathophysiological features of GDM, such as trophoblast dysfunction, changes in intracellular glucose metabolism, and inflammation. Moreover, placenta-specific ncRNAs may be potential diagnostic biomarkers and even therapeutic targets for GDM. This review summarizes data published on the involvement of aberrantly expressed placental ncRNAs in GDM and provides information on their role in the pathogenesis of GDM and GDM-associated complications.

Non-Coding RNAs and Extracellular Vehicles: Their Role in the Pathogenesis of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is defined as glucose intolerance with onset or first recognition in the second or third trimester of pregnancy. GDM has a considerable impact on health outcomes of the mother and offspring during pregnancy, delivery, and beyond. Although the exact mechanism regarding GDM remains unclear, numerous studies have suggested that non-coding RNAs, including long non-coding (lnc)RNAs, microRNAs, and circular RNAs, were involved in the pathogenesis of GDM in which they played vital regulatory roles. Additionally, several studies have revealed that extracellular vehicles also participated in the pathogenesis of GDM, highlighting their important role in this disease. Considering the lack of effective biomarkers for the early identification of and specific treatment for GDM, non-coding RNAs and extracellular vehicles may be promising biomarkers and even targets for GDM therapies. This review provides an update on our understanding of the role of non-coding RNAs and extracellular vehicles in GDM. As our understanding of the function of lncRNAs and extracellular vehicles improves, the future appears promising for their use as potential biomarkers and treatment targets for GDM in clinical practice.

Epigenetic alternations of microRNAs and DNA methylation contribute to gestational diabetes mellitus

This study aimed to identify epigenetic alternations of microRNAs and DNA methylation for gestational diabetes mellitus (GDM) diagnosis and treatment using in silico approach. Data of mRNA and miRNA expression microarray (GSE103552 and GSE104297) and DNA methylation data set (GSE106099) were obtained from the GEO database. Differentially expressed genes (DEGs), differentially expressed miRNAs (DEMs) and differentially methylated genes (DMGs) were obtained by limma package. Functional and enrichment analyses were performed with the DAVID database. The protein‐protein interaction (PPI) network was constructed by STRING and visualized in Cytoscape. Simultaneously, a connectivity map (CMap) analysis was performed to screen potential therapeutic agents for GDM. In GDM, 184 low miRNA‐targeting up‐regulated genes and 234 high miRNA‐targeting down‐regulated genes as well as 364 hypomethylation–high‐expressed genes and 541 hypermethylation–low‐expressed genes were obtained. They were mainly enriched in terms of axon guidance, purine metabolism, focal adhesion and proteasome, respectively. In addition, 115 genes (67 up‐regulated and 48 down‐regulated) were regulated by both aberrant alternations of miRNAs and DNA methylation. Ten chemicals were identified as putative therapeutic agents for GDM and four hub genes (IGF1R, ATG7, DICER1 and RANBP2) were found in PPI and may be associated with GDM. Overall, this study identified a series of differentially expressed genes that are associated with epigenetic alternations of miRNA and DNA methylation in GDM. Ten chemicals and four hub genes may be further explored as potential drugs and targets for GDM diagnosis and treatment, respectively.

MiR-190b impedes pancreatic β cell proliferation and insulin secretion by targeting NKX6-1 and may associate to gestational diabetes mellitus

BACKGROUND

The dysfunction of pancreatic β cells is related to the occurrence of gestational diabetes mellitus (GDM). This study aimed to investigate the mechanism underlying the effects of miR-190b on pancreatic β cell proliferation and insulin secretion.

METHODS

Quantitative real-time PCR was used to detect miR-190b expression in placenta tissues from GDM patients. The effects of miR-190b on islet cells activity, proliferation, and insulin secretion were measured using MTT assay, BrdU staining, and ELISA. The relationship between miR-190b and NK6 homeobox 1 (NKX6-1) was ensured by dual luciferase reporter assay.

RESULTS

MiR-190b was overexpressed in placenta tissues from GDM patients compared to normal pregnant woman. MiR-190b inhibitor inhibited the cell activity, proliferation, and insulin secretion of islet β cells, while miR-190b overexpression had an opposite effect. Additionally, miR-190b negatively regulated NKX6-1 expression. Overexpression of NKX6-1 reversed the inhibitory effect of miR-190b-mimics on islet β cell activity, proliferation, and insulin secretion. In mouse islets, knockdown of miR-190b promoted insulin secretion by up-regulating NKX6-1 expression.

CONCLUSION

Silence of miR-190b accelerated pancreatic β cell proliferation and insulin secretion via targeting NKX6-1, which might be a mechanism underlying the effects of miR-190b on the progression of GDM.

The Role of LIN28-let-7-ARID3B Pathway in Placental Development

Placental disorders are a major cause of pregnancy loss in humans, and 40–60% of embryos are lost between fertilization and birth. Successful embryo implantation and placental development requires rapid proliferation, invasion, and migration of trophoblast cells. In recent years, microRNAs (miRNAs) have emerged as key regulators of molecular pathways involved in trophoblast function. A miRNA binds its target mRNA in the 3ʹ-untranslated region (3ʹ-UTR), causing its degradation or translational repression. Lethal-7 (let-7) miRNAs induce cell differentiation and reduce cell proliferation by targeting proliferation-associated genes. The oncoprotein LIN28 represses the biogenesis of mature let-7 miRNAs. Proliferating cells have high LIN28 and low let-7 miRNAs, whereas differentiating cells have low LIN28 and high let-7 miRNAs. In placenta, low LIN28 and high let-7 miRNAs can lead to reduced proliferation of trophoblast cells, resulting in abnormal placental development. In trophoblast cells, let-7 miRNAs reduce the expression of proliferation factors either directly by binding their mRNA in 3ʹ-UTR or indirectly by targeting the AT-rich interaction domain (ARID)3B complex, a transcription-activating complex comprised of ARID3A, ARID3B, and histone demethylase 4C (KDM4C). In this review, we discuss regulation of trophoblast function by miRNAs, focusing on the role of LIN28-let-7-ARID3B pathway in placental development.

Non-invasive prenatal testing reveals copy number variations related to pregnancy complications

Background

Pregnancy complications could lead to maternal and fetal morbidity and mortality. Early diagnosing and managing complications have been associated with good outcomes. The placenta was an important organ for development of pregnancy complications. Thus, non-invasive prenatal testing technologies could detect genetic variations, such as aneuploidies and sub-chromosomal copy number variations, reflecting defective placenta by maternal plasma cffDNAs. Maternal cffDNAs had been proved to derive from trophoblast cells of placenta.

Results

In order to find out the relationship between genetic variations and pregnancy complications, we reviewed NIPT results for subchromosomal copy number variations in a cohort of 3890 pregnancies without complications and 441 pregnancies with pregnancy complications including gestational diabetes mellitus (GDM), pregnancy-induced hypertension (PIH), preterm prelabor rupture of membranes (PPROM) and placenta implantation abnormalities (PIA). For GDMs, we identified three CNV regions containing some members of alpha- and beta-defensins, such as DEFA1, DEFA3, DEFB1. For PIHs, we found three duplication and one deletion region including Pcdhα, Pcdhβ, and Pcdhγ, known as protocadherins, which were complicated by hypertensive disorders. For PPROMs and PIAs, we identified one and two CNV regions, respectively. SFTPA2, SFTPD and SFTPA1, belonging to surfactant protein, was considered to moderated the inflammatory activation within the fetal extra-embryonic compartment, associated to duration of preterm prelabor rupture of fetal membranes, while MEF2C and TM6SF1 could be involved in trophoblast invasion and differentiation.

Conclusions

Our findings gave a clue to correlation between genetic variations of maternal cell-free DNAs and pregnancy complications.

Electronic supplementary material

The online version of this article (10.1186/s13039-019-0451-3) contains supplementary material, which is available to authorized users.