Differential Expression of miR-136 in Gestational Diabetes Mellitus Mediates the High-Glucose-Induced Trophoblast Cell Injury through Targeting E2F1

The role of microRNAs in pregnancies complicated by maternal diabetes

With the global prevalence of diabetes increasing, more people of reproductive age are experiencing hyperglycaemic pregnancies. Maternal Type 1 (T1DM) or Type 2 (T2DM) diabetes mellitus, and gestational diabetes mellitus (GDM) are associated with maternal cardiovascular and metabolic complications. Pregnancies complicated by maternal diabetes also increase the risk of short- and long-term health complications for the offspring, including altered fetal growth and the onset of T2DM and cardiometabolic diseases throughout life. Despite advanced methods for improving maternal glucose control, the prevalence of adverse maternal and offspring outcomes associated with maternal diabetes remains high. The placenta is a key organ at the maternal-fetal interface that regulates fetal growth and development. In pregnancies complicated by maternal diabetes, altered placental development and function has been linked to adverse outcomes in both mother and fetus. Emerging evidence suggests that microRNAs (miRNAs) are key molecules involved in mediating these changes. In this review, we describe the role of miRNAs in normal pregnancy and discuss how miRNA dysregulation in the placenta and maternal circulation is associated with suboptimal placental development and pregnancy outcomes in individuals with maternal diabetes. We also discuss evidence demonstrating that miRNA dysregulation may affect the long-term health of mothers and their offspring. As such, miRNAs are potential candidates as biomarkers and therapeutic targets in diabetic pregnancies at risk of adverse outcomes.

Phenylbutyric acid inhibits hypoxia-induced trophoblast apoptosis and autophagy in preeclampsia via the PERK/ATF-4/CHOP pathway

Preeclampsia (PE) is a common pregnancy complication with a high mortality rate. Abnormally activated endoplasmic reticulum stress (ERS) is believed to be responsible for the destruction of key placental cells-trophoblasts. Phenylbutyric acid (4-PBA), an ERS inhibitor, is involved in regulating the development of ERS-related diseases. At present, how 4-PBA affects trophoblasts and its mechanisms is still unclear. In this study, PE cell models were established by stimulating HTR-8/SVneo cells with hypoxia. To verify the underlying mechanisms of 4-PBA on PE, CCT020312, an activator of PERK, was also used. The results showed that 4-PBA restored hypoxia-induced trophoblast viability, inhibited HIF-1α protein expression, inflammation, and PERK/ATF-4/CHOP pathway. Hoechst 33342 staining and flow cytometry results confirmed that 4-PBA decreased hypoxia-induced apoptosis in trophoblasts. The results of the JC-1 analysis and apoptosis initiation enzyme activity assay also demonstrated that 4-PBA inhibited apoptosis related to the mitochondrial pathway. Furthermore, by detecting autophagy in trophoblasts, an increased number of autophagic vesicles, damaged mitochondria, enhanced dansylcadaverine fluorescence, enhanced levels of autophagy proteins Beclin-1, LC3II, and decreased p62 were seen in hypoxia-stimulated cells. These changes were reversed by 4-PBA. Furthermore, it was observed that CCT020312 reversed the effects of 4-PBA on the viability, apoptosis, and autophagosome number of hypoxia-induced trophoblasts. In summary, 4-PBA reduces autophagy and apoptosis via the PERK/ATF-4/CHOP pathway and mitochondrial pathway, thereby restoring the viability of hypoxic trophoblasts. These findings provide a solid evidence base for the use of 4-PBA in PE treatment and guide a new direction for improving the outcomes of patients with PE.

Circular RNAs: Emerging Modulators in the Pathophysiology of Polycystic Ovary Syndrome and their Clinical Implications

Polycystic ovary syndrome (PCOS) is a prevalent endocrine/metabolic disorder in women of reproductive age. PCOS is characterized by hyperandrogenism, polycystic ovary morphology, and ovulatory dysfunction/anovulation. It involves multiple effects in patients, including granulosa/theca cell hyperplasia, menstrual disturbances, infertility, acne, obesity, insulin resistance, and cardiovascular disorders. Biochemical analyses and the results of RNA sequencing studies in recent years have shown a type of non-coding RNAs as a splicing product known as circular RNAs (circRNAs). Several biological functions have been identified in relation to circRNAs, including a role in miRNA sponge, protein sequestration, increased parental gene expression, and translation leading to polypeptides. These circular molecules are more plentiful and specialized than other types of RNAs. For this reason, they are referred to as potential biomarkers in different diseases. Evidence suggests that circRNAs may have regulatory potentials through different signaling pathways, such as the miRNA network. Probably most experts in the field of obstetricians are not aware of circRNAs as a useful biomarker. Therefore, this review focused on the researches that have been done on the involvement of circRNAs in PCOS and summarized recent supportive evidence, and evaluated the circRNA association and mechanisms involved in PCOS.

HOXC8 alleviates high glucose-triggered damage of trophoblast cells during gestational diabetes mellitus via activating TGFβ1-mediated Notch1 pathway

Gestational diabetes mellitus (GDM) is an increasingly frequent disease occurred during pregnancy. HOXC8 has been disclosed to take part in the regulation of cancers. Additionally, the HOXC8 expression was dramatically decreased in the placenta of pre-eclampsia patients, but its expression and function have not been investigated in GDM. In this work, it was demonstrated that the mRNA and protein expression of HOXC8 was lower in GDM placenta tissues and GDM cell model. In addition, HOXC8 facilitated trophoblast cell proliferation and weakened trophoblast cell mitochondrial apoptosis. HOXC8 enhanced trophoblast cell migration and angiogenesis. Moreover, HOXC8 activated the TGFβ1-mediated Notch1 signaling pathway. Results showed that the mRNA and protein expressions of TGFβ1 and Notch1 were both lower in the GDM group than that in the NP group. Besides, there were positive correlations among HOXC8, TGFβ1 and Notch1. Inhibition of TGFβ1 (SB202190 treatment) reversed the effects of HOXC8 on trophoblast cells through modulating cell proliferation, mitochondrial apoptosis, migration and angiogenesis. At last, through in vivo experiments, it was identified that HOXC8 relieved GDM symptoms in vivo. In conclusion, HOXC8 alleviated HG-stimulated damage of trophoblast cells during GDM through activating TGFβ1-mediated Notch1 pathway. This discovery may provide a novel and useful bio-target for GDM treatment.

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.

Orphan nuclear receptor NUR77 relieves insulin resistance in HTR-8/SVneo trophoblast cells through activation of autophagy and insulin signaling

Gestational diabetes mellitus (GDM) is a common pregnancy complication with a high incidence in women. Orphan nuclear receptor NUR77 is involved in regulating glucose metabolism. However, its role in GDM has not been fully elucidated yet. In this study, an animal model of GDM was established by feeding mice with a high-fat diet (HFD) before and during pregnancy. NUR77 expression was abnormally upregulated in placenta tissues of GDM mice. We performed gain- and loss-of-function studies of NUR77 in HTR-8/SVneo cells. Cells were incubated with 1 × 10^-6 M insulin for 48 h to induce insulin resistance (IR). The expression of NUR77 was downregulated in HTR-8/SVneo cells following IR induction. Overexpression of NUR77 promoted cell proliferation, migration, and invasion. Notably, NUR77 promoted glucose uptake and enhanced insulin sensitivity in vitro. NUR77 increased the ratio of p-insulin receptor β (IRβ)^Tyr1361/IRβ, p-insulin receptor substrate (IRS)-1^Tyr612/IRS-1, p-Akt/Akt and decreased p-IRS-1^Ser307/IRS-1, as well as lowered the expression of glucose transport protein type 1 (GLUT1) and elevated GLUT4. These results suggest the involvement of IRβ/IRS/Akt/GLUT4 signaling activation in the regulatory effects of NUR77 on IR in HTR-8/SVneo cells. Silencing of NUR77 displayed opposite effects. Besides, NUR77 enhanced the expression of autophagy-related protein Beclin 1 and the ratio of LC3II/LC3I. Further study demonstrated that the inhibitory effect of NUR77 on IR was partially attributed to the activation of autophagy. Therefore, we demonstrate that NUR77 enhances insulin sensitivity in HTR-8/SVneo cells likely through activating IRβ/IRS/Akt/GLUT4 pathway and regulating autophagy.

LncRNA XIST serves as a diagnostic biomarker in gestational diabetes mellitus and its regulatory effect on trophoblast cell via miR-497-5p/FOXO1 axis

Background

Gestational diabetes mellitus (GDM) is increasingly common in pregnancy. This study's purpose was to identify the expression of XIST and manifest the potential mechanism of XIST in GDM.

Methods

Ninety-three patients with GDM and 93 normal pregnant women were included in this investigation. qRT-PCR was conducted to evaluate the expression of miR-497-5p and XIST and the relationship between XIST and fasting blood glucose (FBG) was explored by Pearson assay. The clinical diagnosis of XIST on GDM patients was validated by the receiver operator characteristic (ROC) curve. Cell counting kit-8 (CCK-8) was applied to elucidate cell viability. Luciferase reporter assay was performed to document the relationship among XIST, miR-497-5p, and FOXO1.

Results

The expression of XIST was increased in GDM patients and HTR-8/SVneo cell models caused by high glucose (HG). The expression of XIST was associated with the FBG levels and appeared to be a feasible indicator in discriminating GDM patients. The expression of miR-497-5p was prominently reduced in GDM patients and cell models. Inhibition of XIST might alleviate the adverse function of HG on cell viability via sponging miR-497-5p. FOXO1 was proved to be a downstream target gene of miR-497-5p.

Conclusions

Overexpression of XIST and downregulation of miR-497-5p were indicated in this publication. XIST might serve as a promising diagnostic marker for GDM patients. XIST/miR-497-5p/FOXO1 axis played a critical role in the regulation of trophoblast cells.

Integrated bioinformatics analysis reveals novel key biomarkers and potential candidate small molecule drugs in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is the metabolic disorder that appears during pregnancy. The current investigation aimed to identify central differentially expressed genes (DEGs) in GDM. The transcription profiling by array data (E-MTAB-6418) was obtained from the ArrayExpress database. The DEGs between GDM samples and non-GDM samples were analyzed. Functional enrichment analysis were performed using ToppGene. Then we constructed the protein–protein interaction (PPI) network of DEGs by the Search Tool for the Retrieval of Interacting Genes database (STRING) and module analysis was performed. Subsequently, we constructed the miRNA–hub gene network and TF–hub gene regulatory network. The validation of hub genes was performed through receiver operating characteristic curve (ROC). Finally, the candidate small molecules as potential drugs to treat GDM were predicted by using molecular docking. Through transcription profiling by array data, a total of 869 DEGs were detected including 439 up-regulated and 430 down-regulated genes. Functional enrichment analysis showed these DEGs were mainly enriched in reproduction, cell adhesion, cell surface interactions at the vascular wall and extracellular matrix organization. Ten genes, HSP90AA1, EGFR, RPS13, RBX1, PAK1, FYN, ABL1, SMAD3, STAT3 and PRKCA were associated with GDM, according to ROC analysis. Finally, the most significant small molecules were predicted based on molecular docking. This investigation identified hub genes, signal pathways and therapeutic agents, which might help us, enhance our understanding of the mechanisms of GDM and find some novel therapeutic agents for GDM.

Extracellular vesicles and their role in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a complex disorder that is defined by glucose intolerance with onset during pregnancy. The incidence of GDM is increasing worldwide. Pregnancies complicated with GDM have higher rates of maternal and fetal morbidity with short- and long-term consequences, including increased rates of cardiovascular disease and type II diabetes for both the mother and offspring. The pathophysiology of GDM still remains unclear and there has been interest in the role of small extracellular vesicles (sEVs) in the maternal metabolic adaptations that occur in pregnancy and GDM. Small EVs are nanosized particles that contain bioactive content, including miRNAs and proteins, which are released by cells to provide cell-to-cell communication. Pregnancy induces an increase in total and placental-secreted sEVs across gestation, with a further increase in sEV number and changes in the protein and miRNA composition of these sEVs in GDM. Research has suggested that these sEVs have an impact on maternal adaptations during pregnancy, including targeting the pancreas, skeletal muscle and adipose tissue. Consequently, this review will focus on the differences in total and placental sEVs in GDM compared to normal pregnancy, the role of sEVs in the pathophysiology of GDM and their clinical application as potential GDM biomarkers.