Reduced methylation downregulates CD39/ENTPD1 and ZDHHC14 to suppress trophoblast cell proliferation and invasion: Implications in preeclampsia

DNA methylation landscape in pregnancy-induced hypertension: progress and challenges

Gestational hypertension (PIH), especially pre-eclampsia (PE), is a common complication of pregnancy. This condition poses significant risks to the health of both the mother and the fetus. Emerging evidence suggests that epigenetic modifications, particularly DNA methylation, may play a role in initiating the earliest pathophysiology of PIH. This article describes the relationship between DNA methylation and placental trophoblast function, genes associated with the placental microenvironment, the placental vascular system, and maternal blood and vascular function, abnormalities of umbilical cord blood and vascular function in the onset and progression of PIH, as well as changes in DNA methylation in the progeny of PIH, in terms of maternal, fetal, and offspring. We also explore the latest research on DNA methylation-based early detection, diagnosis and potential therapeutic strategies for PIH. This will enable the field of DNA methylation research to continue to enhance our understanding of the epigenetic regulation of PIH genes and identify potential therapeutic targets.

Endogenous retroviral solo-LTRs in human genome

Human endogenous retroviruses (HERVs) are derived from the infection and integration of exogenetic retroviruses. HERVs account for 8% of human genome, and the majority of HERVs are solitary LTRs (solo-LTRs) due to homologous recombination. Multiple findings have showed that solo-LTRs could provide an enormous reservoir of transcriptional regulatory sequences involved in diverse biological processes, especially carcinogenesis and cancer development. The link between solo-LTRs and human diseases still remains poorly understood. This review focuses on the regulatory modules of solo-LTRs, which contribute greatly to the diversification and evolution of human genes. More importantly, although inactivating mutations, insertions and deletions have been identified in solo-LTRs, the inherited regulatory elements of solo-LTRs initiate the expression of chimeric lncRNA transcripts, which have been reported to play crucial roles in human health and disease. These findings provide valuable insights into the evolutionary and functional mechanisms underlying the presence of HERVs in human genome. Taken together, in this review, we will present evidences showing the regulatory and encoding capacity of solo-LTRs as well as the significant impact on various aspects of human biology.

MicroRNA-206 Contributes to the Progression of Preeclampsia by Suppressing the Viability and Mobility of Trophocytes via the Inhibition of AGTR1

The development of preeclampsia (PE) is associated with the impaired trophoblast motility. MicroRNAs (miRs) contribute to the modulation of trophoblast invasion. In the current study, the role of miR-206/AGTR1 in the TNF-alpha-induced invasion defect of trophoblasts was explored. The levels of miR-206 and ATGR1 in clinical placenta tissues were investigated. Trophoblasts were treated with TNF-alpha, and the levels of miR-206 and ATGR1 were modulated. Changes in cell viability, invasion, and inflammation in trophoblasts were detected. The level of miR-206 was induced, while the level of AGTR1 was suppressed in placenta tissues. In in vitro assays, TNF-alpha suppressed viability, induced inflammatory response, inhibited invasion, upregulated miR-206, and down-regulated AGTR1. The inhibited expression of miR-206 or the overexpression of AGTR1 counteracted the effects of TNF-alpha, indicating the key role of the miR-206/AGTR1 in progression of PE. Collectively, miR-206 suppressed viability, induced inflammatory response, and decreased invasion of trophoblasts by inhibiting AGTR1.

CD39 abrogates platelet-derived factors induced IL-1β expression in the human placenta

Tissue insults in response to inflammation, hypoxia and ischemia are accompanied by the release of ATP into the extracellular space. There, ATP modulates several pathological processes, including chemotaxis, inflammasome induction and platelet activation. ATP hydrolysis is significantly enhanced in human pregnancy, suggesting that increased conversion of extracellular ATP is an important anti-inflammatory process in preventing exaggerated inflammation, platelet activation and hemostasis in gestation. Extracellular ATP is converted into AMP, and subsequently into adenosine by the two major nucleotide-metabolizing enzymes CD39 and CD73. Here, we aimed to elucidate developmental changes of placental CD39 and CD73 over gestation, compared their expression in placental tissue from patients with preeclampsia and healthy controls, and analyzed their regulation in response to platelet-derived factors and different oxygen conditions in placental explants as well as the trophoblast cell line BeWo. Linear regression analysis showed a significant increase in placental CD39 expression, while at the same time CD73 levels declined at term of pregnancy. Neither maternal smoking during first trimester, fetal sex, maternal age, nor maternal BMI revealed any effects on placental CD39 and CD73 expression. Immunohistochemistry detected both, CD39 and CD73, predominantly in the syncytiotrophoblast layer. Placental CD39 and CD73 expression were significantly increased in pregnancies complicated with preeclampsia, when compared to controls. Cultivation of placental explants under different oxygen conditions had no effect on the ectonucleotidases, whereas presence of platelet releasate from pregnant women led to deregulated CD39 expression. Overexpression of recombinant human CD39 in BeWo cells decreased extracellular ATP levels after culture in presence of platelet-derived factors. Moreover, platelet-derived factors-induced upregulation of the pro-inflammatory cytokine, interleukin-1β, was abolished by CD39 overexpression. Our study shows that placental CD39 is upregulated in preeclampsia, suggesting an increasing demand for extracellular ATP hydrolysis at the utero-placental interface. Increased placental CD39 in response to platelet-derived factors may lead to enhanced conversion of extracellular ATP levels, which in turn could represent an important anti-coagulant defense mechanism of the placenta.

GWAS of Reproductive Traits in Large White Pigs on Chip and Imputed Whole-Genome Sequencing Data

Total number born (TNB), number of stillborn (NSB), and gestation length (GL) are economically important traits in pig production, and disentangling the molecular mechanisms associated with traits can provide valuable insights into their genetic structure. Genotype imputation can be used as a practical tool to improve the marker density of single-nucleotide polymorphism (SNP) chips based on sequence data, thereby dramatically improving the power of genome-wide association studies (GWAS). In this study, we applied Beagle software to impute the 50 K chip data to the whole-genome sequencing (WGS) data with average imputation accuracy (R2) of 0.876. The target pigs, 2655 Large White pigs introduced from Canadian and French lines, were genotyped by a GeneSeek Porcine 50K chip. The 30 Large White reference pigs were the key ancestral individuals sequenced by whole-genome resequencing. To avoid population stratification, we identified genetic variants associated with reproductive traits by performing within-population GWAS and cross-population meta-analyses with data before and after imputation. Finally, several genes were detected and regarded as potential candidate genes for each of the traits: for the TNB trait: NOTCH2, KLF3, PLXDC2, NDUFV1, TLR10, CDC14A, EPC2, ORC4, ACVR2A, and GSC; for the NSB trait: NUB1, TGFBR3, ZDHHC14, FGF14, BAIAP2L1, EVI5, TAF1B, and BCAR3; for the GL trait: PPP2R2B, AMBP, MALRD1, HOXA11, and BICC1. In conclusion, expanding the size of the reference population and finding an optimal imputation strategy to ensure that more loci are obtained for GWAS under high imputation accuracy will contribute to the identification of causal mutations in pig breeding.

Transcriptional Factor Forkhead Box D1 Upregulates Sirtuin3 by Activating the Wnt/β-Catenin Pathway to Alleviate HTR-8/Svneo Trophoblast Cell Dysfunction in Preeclampsia

The proliferation, invasion, migration and apoptosis of trophoblast cells in preeclampsia are closely related to the occurrence and development of preeclampsia. Transcription factors forkhead box D1 and Sirtuin3 are abnormally expressed in preeclampsia, and Sirtuin3 plays a regulatory role in cell proliferation, invasion and apoptosis in related diseases. However, the studies on forkhead box D1 and Sirtuin3 in preeclampsia and their specific mechanisms have not been reported so far. In this study, the expression of Sirtuin3 in Human chorionic trophoblast cells HTR-8/Svneo was inhibited by cell transfection, and then the effects of Sirtuin3 expression in interfering cells on cell invasion, migration and apoptosis were detected by MTT, TUNEL, Western blot, wound healing and Transwell techniques. Subsequently, the binding between forkhead box D1 and Sirtuin3 was predicted by JASPAR website and verified by luciferase assay and ChIP assay. Finally, cell invasion, migration and apoptosis were detected after overexpression of forkhead box D1 and interference with Sirtuin3, and the Wnt/β-catenin signaling pathway was detected to explore the mechanism. We found that interfering with Sirtuin3 induced apoptosis of HTR-8/Svneo cells and inhibited cell invasion and migration. Forkhead box D1 transcriptional activation of Sirtuin3 alleviated HTR-8/SVneo cell dysfunction through activation of the Wnt/β-catenin signaling pathway. Overall, transcriptional factor forkhead box D1 can upregulate Sirtuin3 by activating the Wnt/β-catenin pathway to alleviate HTR-8/Svneo trophoblast cell dysfunction in preeclampsia.

Evaluation of CD39, CD73, HIF-1α, and their related miRNAs expression in decidua of preeclampsia cases compared to healthy pregnant women

BACKGROUND

The Preeclampsia (PE) molecular mechanisms are not fully revealed and different biological processes are involved in the pathogenesis of PE. We aimed to evaluate adenosine and hypoxia-related signaling molecules in PE patients in the current study.

METHODS

Decidua tissue and peripheral blood samples were taken from 25 healthy pregnant and 25 PE women at delivery time. CD39, CD73, and Hypoxia-inducible factor-alpha (HIF-α) were evaluated in mRNA and protein level using real-time PCR and western blotting techniques, respectively. Also, miR-30a, miR-206, and miR-18a expression were evaluated by real-time PCR. At last, secretion levels of IGF and TGF-β in the taken serum of blood samples were measured by ELISA.

RESULTS

Our results revealed that Expression of CD39 is decreased in PE cases versus healthy controls at mRNA and protein levels (p = 0.0003 for both). CD73 and HIF-α showed an increased level of expression in PE patients at RNA and protein status (p = 0.0157 and p < 0.0001 for protein evaluation of CD73 and HIF-α, respectively). The miRNA-30a (p = 0.0037) and miR-206 (p = 0.0113) showed elevated expression in the decidua of the PE group. The concentration of secreted IGF-1 (p = 0.0002) and TGF-β (p = 0.0101) in serum samples of PE cases compared to the healthy group were decreased.

CONCLUSION

In conclusion, our results showed that aberrant expression of molecules that are involved in ATP catabolism and the hypoxic conditions is observed in PE cases and involved in their hypertension and inflammation could be served as PE prognosis by more confirming in comprehensive future studies. miR-206 and miR-30a play a role by regulating CD39 and CD73 as molecules that are involved in ATP catabolism as well as regulating the production of IGF-1 in the process of hypertension, which is the main feature in patients with preeclampsia. On the other hand, decreased level of miR-18a lead to upregulation of HIF-1a, and the consequence condition of hypoxia increases hypertension and inflammation in these patients.

Maternal platelets at the first trimester maternal-placental interface - Small players with great impact on placenta development

In human pregnancy, maternal platelet counts decrease with each trimester, reaching a reduction by approximately ten percent at term in uncomplicated cases and recover to the levels of the non-pregnant state a few weeks postpartum. The time when maternal platelets start to occur in the early human placenta most likely coincides with the appearance of loosely cohesive endovascular trophoblast plugs showing capillary-sized channels by mid first trimester. At that time, platelets accumulate in intercellular gaps of anchoring parts of trophoblast columns and start to adhere to the surface of placental villi and the chorionic plate. This is considered as normal process that contributes to placenta development by acting on both the extravillous- and the villous trophoblast compartment. Release of platelet cargo into intercellular gaps of anchoring cell columns may affect partial epithelial-to-mesenchymal transition and invasiveness of extravillous trophoblasts as well as deposition of fibrinoid in the basal plate. Activation of maternal platelets on the villous surface leads to perivillous fibrin-type fibrinoid deposition, contributing to the shaping of the developing placental villi and the intervillous space. In contrast, excess platelet activation at the villous surface leads to deregulation of the endocrine activity, sterile inflammation and local apoptosis of the syncytiotrophoblast. Platelets and their released cargo are adapted to pregnancy, and may be altered in high-risk pregnancies. Identification of different maternal platelet subpopulations, which show differential procoagulant ability and different response to anti-platelet therapy, are promising new future directions in deciphering the role of maternal platelets in human placenta physiology.

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.

Maternal platelets pass interstices of trophoblast columns and are not activated by HLA-G in early human pregnancy

In early human gestation, maternal arterial blood flow into the intervillous space of the developing placenta is obstructed by invaded trophoblasts, which form cellular plugs in uterine spiral arteries. These trophoblast plugs have recently been described to be loosely cohesive with clear capillary-sized channels into the intervillous space by 7 weeks of gestation. Here, we analysed localisation of maternal platelets at the maternal-foetal interface of human first trimester pregnancy, and tested the hypothesis whether HLA-G, which is primarily expressed by extravillous trophoblasts, affects aggregation and adhesion of isolated platelets. Immunohistochemistry of first trimester placental sections localised maternal platelets in vessel-like channels and adjacent intercellular gaps of extravillous trophoblasts in distal parts of columns. Furthermore, this localisation was confirmed by transmission electron microscopy. Neither co-incubation of HLA-G overexpressing JAR cells with isolated platelets, nor incubation with cell-derived soluble HLA-G or recombinant HLA-G affected platelet adhesion and aggregation. Our study suggests that maternal platelets flow through vessel-like channels of distal trophoblast columns and spread into adjacent lateral intercellular gaps, where platelet-derived factors could contribute to trophoblast differentiation into the invasive phenotype.

Serum amphiregulin and cerebellin-1 levels in severe preeclampsia

PURPOSE

Preeclampsia is a form of hypertensive disorders of pregnancy and defined as the presence of new-onset hypertension and proteinuria or other end organ damage occurring after 20-week gestation. Preeclampsia can be a destructive process that can cause maternal and infant mortality. The exact etiopathogenesis of preeclampsia is still undefined. We aimed to compare serum amphiregulin and cerebellin-1 levels of severe preeclampsia patients with healthy pregnant women and healthy control subjects.

MATERIALS AND METHODS

A total of 88 women were enrolled in this study. Patients diagnosed with severe preeclampsia were group 1 (n = 28), healthy non-pregnant normotensive women group 2 (n = 30), and healthy pregnant women group 3 (n = 30). The participants in each group were matched for age. Pregnant women in groups 1 and 3 were also matched for gestational age. Serum amphiregulin and cerebellin-1 levels were measured using ELISA.

RESULTS

Serum amphiregulin levels were 3413 ± 1.38 ng/ml (1748-7739), 8510 ± 7213 ng/ml (2019-24,000), and 6580 ± 5360 ng/ml (2484-24,000) in preeclampsia patients, controls and healthy pregnant women, respectively. Amphiregulin levels were significantly lower in preeclampsia patients than healthy pregnant women (p=.008) and controls (p = .015). Amphiregulin levels were similar between healthy controls and healthy pregnant women (p  =  1.00). Cerebellin-1 levels were 222.039 ± 92.681 pg/ml (138,580-557,757) in preeclamptic patients, 537.043 ± 525.117 pg/ml (150,432-1,600,000) in controls and 415.091 ± 436.580 pg/ml (137,284-1,600,000) in healthy pregnant women. Cerebellin-1 levels were similar among groups (p = .272). Serum amphiregulin and cerebellin-1 levels were significantly and positively correlated with each other in preeclampsia patients (r  =  0.693, p < .001), controls (r  =  0.882, p < .001), and healthy pregnant women (r  =  0.591, p = .001). Serum level of amphiregulin ≤3590 pg/ml had a sensitivity of 67.9% and specificity of 63.3% in the diagnosis of preeclampsia (AUC: 0.751; p = .001).

CONCLUSIONS

Serum amphiregulin decreases in severe preeclampsia patients.

Further confirmation of second- and third-generation Eimeria necatrix merozoite DEGs using suppression subtractive hybridization

In our previous study, we obtained a large number of differentially expressed genes (DEGs) between second-generation merozoites (MZ-2) and third-generation merozoites (MZ-3) of Eimeria necatrix using RNA sequencing (RNA-seq). Here, we report two subtractive cDNA libraries for MZ₂ (forward library) and MZ₃ (reverse library) that were constructed using suppression subtractive hybridization (SSH). PCR amplification revealed that the MZ₂ and MZ₃ libraries contained approximately 96.7% and 95% recombinant clones, respectively, and the length of the inserted fragments ranged from 0.5 to 1.5 kb. A total of 106 and 111 unique sequences were obtained from the MZ₂ and MZ₃ libraries, respectively, and were assembled into 13 specific consensus sequences (contigs or genes) (5 from MZ₂ and 8 from MZ₃). The qRT-PCR results revealed that 11 out of 13 genes were differentially expressed between MZ-2 and MZ-3. Of 13 genes, 11 genes were found in both SSH and our RNA-seq data and displayed a similar expression trend between SSH and RNA-seq data, and the remaining 2 genes have not been reported in both E. necatrix genome and our RNA-seq data. Among the 11 genes, the expression trends of 8 genes were highly consistent between SSH and our RNA-seq data. These DEGs may provide specialized functions related to the life-cycle transitions of Eimeria species.