MicroRNAs: key regulators of the trophoblast function in pregnancy disorders

Decoding the molecular pathways governing trophoblast migration and placental development; a literature review

Placental development is a multifaceted process critical for a fruitful pregnancy, reinforced by a complex network of molecular pathways that synchronize trophoblast migration, differentiation, and overall placental function. This review provides an in-depth analysis of the key signaling pathways, such as Wnt, Notch, TGF-β, and VEGF, which play fundamental roles in trophoblast proliferation, invasion, and the complicated process of placental vascular development. For instance, the Wnt signaling pathway is essential to balance trophoblast stem cell proliferation and differentiation, while Notch signaling stimulates cell fate decisions and invasive behavior. TGF-β signaling plays a critical role in trophoblast invasion and differentiation, predominantly in response to the low oxygen environment of early pregnancy, regulated by hypoxia-inducible factors (HIFs). These factors promote trophoblast adaptation, ensure proper placental attachment and vascularization, and facilitate adequate fetal-maternal exchange. Further, we explore the epigenetic and post-transcriptional regulatory mechanisms that regulate trophoblast function, including DNA methylation and the contribution of non-coding RNAs, which contribute to the fine-tuning of gene expression during placental development. Dysregulation of these pathways is associated with severe pregnancy complications, such as preeclampsia, intrauterine growth restriction, and recurrent miscarriage, emphasizing the critical need for targeted therapeutic strategies. Finally, emerging technologies like trophoblast organoids, single-cell RNA sequencing, and placenta-on-chip models are discussed as innovative tools that hold promise for advancing our understanding of placental biology and developing novel interventions to improve pregnancy outcomes. This review emphasizes the importance of understanding these molecular mechanisms to better address placental dysfunctions and associated pregnancy disorders.

Association of the miR-143 Gene rs353292 Polymorphism with Recurrent Pregnancy Loss in Caucasian Women: A Novel Finding in a Multifactorial Devastating Problem

The purpose of this prospective case-control study is to investigate the correlation of the miR-143 gene rs353292 polymorphism in Caucasian women with recurrent pregnancy loss (RPL) compared to a matched control group with at least one live birth and without pregnancy losses. In total, 110 women with recurrent pregnancy losses and 95 control women were recruited. Peripheral blood was collected from all women, and the isolation of DNA was performed with Monarch Genomic DNA Purification. Polymerase chain reaction was applied to amplify the DNA sequence of the miR-143 gene promoter, carrying the polymorphism rs353292. The incidence of genotype CC in the RPL group was statistically significantly higher than in control group (p < 0.0001). Allele C (CT + CC) in the control group was found in 47.36%, and in the RPL group was found in 68.17% (p = 0.006). SNP rs353292 T>C was associated with increased risk of recurrent pregnancy loss. The calculated odds ratio for CT + CC vs. TT and for CC vs. TT were significant higher (p = 0.0028 and p < 0.0001, respectively). The study results suggest that the rs353292 polymorphism is associated with a statistically significant increase in RPL prevalence. The present study provides additional evidence in favor of a shared pathophysiological mechanism that contributes to both RPLs, potentially through inflammatory processes and epithelial-mesenchymal transition dysregulation.

Cleistocalyx nervosum var. paniala mitigates oxidative stress and inflammation induced by PM10 soluble extract in trophoblast cells via miR-146a-5p

Air pollution poses a significant global concern, notably impacting pregnancy outcomes through mechanisms such as DNA damage, oxidative stress, inflammation, and altered miRNA expression, all of which can adversely affect trophoblast functions. Cleistocalyx nervosum var. paniala, known for its abundance of anthocyanins with diverse biological activities including anti-mutagenic, antioxidant, and anti-inflammatory properties, is the focus of this study examining its effect on Particulate Matter 10 (PM10) soluble extract-induced trophoblast cell dysfunction via miRNA expression. The study involved the extraction of C. nervosum fruit using 70% ethanol, followed by fractionation with hexane, dichloromethane, and ethyl acetate. Subsequent testing for total phenolics, flavonoids, anthocyanins, and antioxidant activity revealed the ethyl acetate fraction (CN-EtOAcF) as possessing the highest phenolic and anthocyanin content along with potent antioxidant activity, prompting its selection for further investigation. In vitro studies on HTR-8/SVneo cells demonstrated that 5-10 µg/mL PM10 soluble extract exposure inhibited cell proliferation, migration, invasion, and induced apoptosis. However, pretreatment with 20-80 µg/mL CN-EtOAcF followed by 5 µg/mL PM10 soluble extract exposure exhibited protective effects against PM10 soluble extract-induced damage, including inflammation inhibition and intracellular ROS suppression. Notably, CN-EtOAcF down-regulated PM10-induced miR-146a-5p expression, with SOX5 identified as a potential target. Overall, CN-EtOAcF demonstrated the potential to protect against PM10-induced harm in trophoblast cells, suggesting its possible application in future therapeutic approaches.

Altered microRNA composition in the uterine lumen fluid in cattle (Bos taurus) pregnancies initiated by artificial insemination or transfer of an in vitro produced embryo

BACKGROUND

MicroRNAs (miRNAs) are presented in the uterine lumen of many mammals, and in vitro experiments have determined that several miRNAs are important for the regulation of endometrial and trophoblast functions. Our aim was to identify and contrast the miRNAs present in extracellular vesicles (EVs) in the uterine lumen fluid (ULF) at the onset of attachment in cattle pregnancies (gestation d 18) initiated by artificial insemination (AI) or by the transfer of an in vitro-produced blastocyst (IVP-ET). A third group had no conceptus after the transfer of an IVP embryo.

RESULTS

The abundance of 263 annotated miRNAs was quantified in the EVs collected from ULF. There was an increase in the transcript abundance of 20 miRNAs in the ULF EVs from the AI pregnant group, while 4 miRNAs had a lower abundance relative to the group not containing a conceptus. Additionally, 4 miRNAs were more abundant in ULF EVs in the AI pregnant group relative to IVP-ET group (bta-mir-17, bta-mir-7-3, MIR7-1, MIR18A). Specific miRNAs in the ULF EVs were co-expressed with messenger RNAs expressed in extra-embryonic tissues and endometrium, including genes that are known to be their targets.

CONCLUSIONS

The results provide biological insights into the participation of miRNAs in the regulation of trophoblast proliferation and differentiation, as well as in endometrium receptivity. The knowledge that in vitro cultured embryos can contribute to the altered abundance of specific miRNAs in the uterine lumen can lead to the development of corrective approaches to reduce conceptus losses during the first month of pregnancy in cattle.

MicroRNA dysregulation and its impact on apoptosis-related signaling pathways in myelodysplastic syndrome

Myelodysplastic syndrome (MDS) holds a unique position among blood cancers, encompassing a spectrum of blood-related disorders marked by impaired maturation of blood cell precursors, bone marrow abnormalities, genetic instability, and a higher likelihood of progressing to acute myeloid leukemia. MicroRNAs (miRNAs), short non-coding RNA molecules typically 18-24 nucleotides in length, are known to regulate gene expression and contribute to various biological processes, including cellular differentiation and programmed cell death. Additionally, miRNAs are involved in many aspects of cancer development, influencing cell growth, transformation, and apoptosis. In this study, we explore the impact of microRNAs on cellular apoptosis in MDS.

MicroRNA Associations with Preterm Labor-A Systematic Review

This systematic review delves into the connections between microRNAs and preterm labor, with a focus on identifying diagnostic and prognostic markers for this crucial pregnancy complication. Covering studies disseminated from 2018 to 2023, the review integrates discoveries from diverse pregnancy-related scenarios, encompassing gestational diabetes, hypertensive disorders and pregnancy loss. Through meticulous search strategies and rigorous quality assessments, 47 relevant studies were incorporated. The synthesis highlights the transformative potential of microRNAs as valuable diagnostic tools, offering promising avenues for early intervention. Notably, specific miRNAs demonstrate robust predictive capabilities. In conclusion, this comprehensive analysis lays the foundation for subsequent research, intervention strategies and improved outcomes in the realm of preterm labor.

Implications for miR-339-5p regulation of trophoblast proliferation and migration in placentas associated with porcine intrauterine growth retardation using integrated transcriptome sequencing analysis

Placental dysfunction is considered as one of the main etiologies of fetal intrauterine growth retardation (IUGR). MicroRNAs (miRNAs) have been demonstrated to be a vital epigenetic modification involved in regulating the placental function and pregnancy outcomes in mammals. However, the mechanisms underlying placenta-specific miRNAs involved in the occurrence and development of pig IUGR remain unclear. In this work, we compared the placental morphologies of piglets with IUGR and normal birth weight (NBW) by using histomorphological analysis and performed a miRNA-mRNA integrative analysis of the gene expression profiles of IUGR and NBW placentas through RNA sequencing. We also investigated the role of differentially expressed ssc-miR-339-5p/GRIK3 through an in vitro experiment on porcine trophoblast cells (PTr2). IUGR piglets had significantly lower birth weight, placental weight, placental efficiency, and placental villus and capillary densities compared with the NBW piglets (P < 0.05). A total of 81 differentially expressed miRNAs and 726 differentially expressed genes in the placentas were screened out between the IUGR and NBW groups. The miRNA-mRNA interaction networks revealed the key core miRNA (ssc-miR-339-5p) and its corresponding target genes. Subsequently, we found that upregulation of ssc-miR-339-5p significantly inhibited the migration and proliferation of PTr2 cells (P < 0.05). The dual-luciferase reporter system showed that GRIK3 was the target gene of ssc-miR-339-5p, and the transcription level of GRIK3 may be negatively regulated by ssc-miR-339-5p. Additionally, overexpression of ssc-miR-339-5p significantly increased (P < 0.05) the mRNA expression levels of genes involved in the cytokine-cytokine receptor interaction pathway. These results indicate that ssc-miR-339-5p may affect the migration and proliferation of trophoblast cells by regulating the expression of GRIK3 and altering the placental inflammatory response, resulting in a suboptimal morphology and function of the placenta and the development of pig IUGR.

MicroRNAs targeting peroxisome proliferator-activated receptor (PPAR) gene are differentially expressed in low birth weight placentae

INTRODUCTION

Peroxisome proliferator-activated receptors (PPARs) are activated by natural ligands like fatty acids and influence placental angiogenesis and pregnancy outcome. However, the underlying molecular mechanisms are not clear. This study aims to investigate the association of maternal and placental fatty acid levels with DNA methylation and microRNA regulation of PPARs in the placentae of women delivering low birth weight (LBW) babies.

METHODS

This study includes 100 women delivering normal birth weight (NBW) baby and 70 women delivering LBW baby. Maternal and placental fatty acids levels were estimated by gas chromatograph. Gene promoter methylation and mRNA expression of PPARs was analyzed using Epitect Methyl-II PCR assay kit and RT-PCR respectively. Expression of miRNAs targeting PPAR mRNA were analyzed using a Qiagen miRCURY LNA PCR Array on RT-PCR.

RESULTS

Placental docosahexaenoic acid (DHA) levels and placental mRNA expression of PPARα and PPARγ were lower (p < 0.05 for all) in the LBW group. Differential expression of miRNAs (upregulated miR-33a-5p and miR-22-5p; downregulated miR-301a-5p, miR-518d-5p, miR-27b-5p, miR-106a-5p, miR-21-5p, miR-548d-5p, miR-17-5p and miR-20a-5p) (p < 0.05 for all) was observed in the LBW group. Maternal and placental polyunsaturated fatty acids and total omega-3 fatty acids were positively associated while saturated fatty acids were negatively associated with expression of miRNAs (p < 0.05 for all). Placental expression of miRNAs were positively associated with birth weight (p < 0.05 for all).

DISCUSSION

Our data suggests that maternal fatty acid status is associated with changes in the placental expression of miRNAs targeting PPAR gene in women delivering LBW babies.