HGF promotes HTR-8/SVneo cell migration through activation of MAPK/PKA signaling leading to up-regulation of WNT ligands and integrins that target β-catenin

Uterine WNTS modulates fibronectin binding activity required for blastocyst attachment through the WNT/CA2+ signaling pathway in mice

Adhesion of the implanting blastocyst involves the interaction between integrin proteins expressed by trophoblast cells and components present in the basement membrane of the endometrial luminal epithelium. Although several factors regulating integrins and their adhesion to fibronectin are already known, we showed that Wnt signaling is involved in the regulation of blastocyst adhesion through the trafficking of integrins expressed by trophoblast cells. Localization of Itgα5β1 by immunofluorescence and FN-binding assays were conducted on peri-implantation blastocysts treated with either Wnt5a or Wnt7a proteins. Both Wnt5a and Wnt7a induced a translocation of Itgα5β1 at the surface of the blastocyst and an increase in FN-binding activity. We further demonstrated that uterine fluid is capable of inducing integrin translocation and this activity can be specifically inhibited by the Wnt inhibitor sFRP2. To identify the Wnt signaling pathway involved in this activity, blastocysts were incubated with inhibitors of either p38MAPK, PI3K pathway or CamKII prior to the addition of Wnts. Whereas inhibition of p38MAPK and PI3K had not effect, inhibition of CamKII reduced FN-binding activity induced by Wnts. Finally, we demonstrated that inhibition of Wnts by sFRP2 reduced the binding efficiency of the blastocyst to uterine epithelial cells. Our findings provide new insight into the mechanism that regulates integrin trafficking and FN-binding activity and identifies Wnts as a key player in blastocyst attachment to the uterine epithelium.

Endometrial small extracellular vesicles regulate human trophectodermal cell invasion by reprogramming the phosphoproteome landscape

A series of cyclical events within the uterus are crucial for pregnancy establishment. These include endometrial regeneration following menses, under the influence of estrogen (proliferative phase), then endometrial differentiation driven by estrogen/progesterone (secretory phase), to provide a microenvironment enabling attachment of embryo (as a hatched blastocyst) to the endometrial epithelium. This is followed by invasion of trophectodermal cells (the outer layer of the blastocyst) into the endometrium tissue to facilitate intrauterine development. Small extracellular vesicles (sEVs) released by endometrial epithelial cells during the secretory phase have been shown to facilitate trophoblast invasion; however, the molecular mechanisms that underline this process remain poorly understood. Here, we show that density gradient purified sEVs (1.06-1.11 g/ml, Alix⁺ and TSG101⁺, ∼180 nm) from human endometrial epithelial cells (hormonally primed with estrogen and progesterone vs. estrogen alone) are readily internalized by a human trophectodermal stem cell line and promote their invasion into Matrigel matrix. Mass spectrometry-based proteome analysis revealed that sEVs reprogrammed trophectoderm cell proteome and their cell surface proteome (surfaceome) to support this invasive phenotype through upregulation of pro-invasive regulators associated with focal adhesions (NRP1, PTPRK, ROCK2, TEK), embryo implantation (FBLN1, NIBAN2, BSG), and kinase receptors (EPHB4/B2, ERBB2, STRAP). Kinase substrate prediction highlighted a central role of MAPK3 as an upstream kinase regulating target cell proteome reprogramming. Phosphoproteome analysis pinpointed upregulation of MAPK3 T204/T202 phosphosites in hTSCs following sEV delivery, and that their pharmacological inhibition significantly abrogated invasion. This study provides novel molecular insights into endometrial sEVs orchestrating trophoblast invasion, highlighting the microenvironmental regulation of hTSCs during embryo implantation.

Construction of HGF-Displaying Yeast by Cell Surface Engineering

Hepatocyte growth factor (HGF) has been investigated as a regulator for immune reactions caused by transplantation and autoimmune diseases and other biological functions. Previous studies demonstrated that cDNA-encoding HGF administration could inhibit acute graft-versus-host disease (GVHD) after treatment via hematopoietic stem cell transplantation. This study aimed to show the preparation of HGF protein on yeast cell surfaces to develop a tool for the oral administration of HGF to a GVHD mouse model. In this study, full-length HGF and the heavy chain of HGF were genetically fused with α-agglutinin and were successfully displayed on the yeast cell surface. This study suggested that yeast cell surface display engineering could provide a novel administration route for HGF.

A MET-PTPRK kinase-phosphatase rheostat controls ZNRF3 and Wnt signaling

Zinc and ring finger 3 (ZNRF3) is a transmembrane E3 ubiquitin ligase that targets Wnt receptors for ubiquitination and lysosomal degradation. Previously, we showed that dephosphorylation of an endocytic tyrosine motif (4Y motif) in ZNRF3 by protein tyrosine phosphatase receptor-type kappa (PTPRK) promotes ZNRF3 internalization and Wnt receptor degradation (Chang et al 2020). However, a responsible protein tyrosine kinase(s) (PTK) phosphorylating the 4Y motif remained elusive. Here we identify the proto-oncogene MET (mesenchymal-epithelial transition factor) as a 4Y kinase. MET binds to ZNRF3 and induces 4Y phosphorylation, stimulated by the MET ligand HGF (hepatocyte growth factor, scatter factor). HGF-MET signaling reduces ZNRF3-dependent Wnt receptor degradation thereby enhancing Wnt/β-catenin signaling. Conversely, depletion or pharmacological inhibition of MET promotes the internalization of ZNRF3 and Wnt receptor degradation. We conclude that HGF-MET signaling phosphorylates- and PTPRK dephosphorylates ZNRF3 to regulate ZNRF3 internalization, functioning as a rheostat for Wnt signaling that may offer novel opportunities for therapeutic intervention.

Impaction of factors associated with oxidative stress on the pathogenesis of gestational hypertension and preeclampsia: A Chinese patients based study

We aimed to investigate the effect of Kelch-like ECH-associated protein 1/NF-E2 p45-related factor 2 (Keap1/Nrf2) pathway on the biological function of trophoblast cells in oxidative stress model at the cellular level, and analyzed the expression level and clinical significance of Keap1/Nrf2 pathway and related antioxidant factors in placental tissues of Preeclampsia (PE) patients at clinical level. In present study, we found that under hypoxia/reoxygenation conditions, the activity of oxidative stress-related enzymes (CAT, GSH-Px, SOD) in HTR8/SVneo cells was significantly lower than that before treatment (P < .01). The activities of CAT, GSH-Px and SOD in HTR8/SVneo cells in SiRNA+H/R group decreased significantly (P < .01), indicating the important defense effect of Keap1/Nrf2 signaling pathway in oxidative stress. As a control group of Nrf2 SiRNA+H/R group, Si-NC+H/R group had CAT, GSH-Px and SOD activities decreasing, which was similar to that in H/R group. Moreover, the activities of oxidative stress-related active enzymes in patients with PE were further confirmed by detecting and comparing the activities of CAT, GSH-Px and SOD in placental tissues. The results showed that the activity of SOD (P < .001), GSH-Px (P < .01) and CAT (P < .01) in placental tissues of patients with PE were significant different from those of normal placental tissues. The expression level of Keap1 in placenta of patients with PE was slightly lower than that of normal placenta. While the expression of Nrf2 in placenta of patients with PE was significantly higher than that of normal placenta. HO-1 expression in placenta of patients with PE was significantly higher than that of normal placenta. These results implicate the importance of Keap-1/Nrf2 pathway in PE.

The Involvement of Cell Adhesion Molecules, Tight Junctions, and Gap Junctions in Human Placentation

Placentation is a major determinant of the success of pregnancy. It is regulated by several factors such as cell adhesion molecules, tight junctions, and gap junctions. The cell adhesion molecules are integrins, cadherins, immunoglobulins, nectins, and selectins. The tight junctions are composed of claudins, occludin, and junction adhesion molecule proteins while the gap junctions are composed of connexins of varying molecular weights. During placentation, some of these molecules regulate trophoblast proliferation, trophoblast fusion, trophoblast migration, trophoblast invasion, trophoblast-endothelium adhesion, glandular remodeling, and spiral artery remodeling. There is a dysregulated placental expression of some of these molecules during obstetric complications. We have, hereby, indicated the expression patterns of the subunits of each of these molecules in the various trophoblast subtypes and in the decidua, and have highlighted their involvement in physiological and pathological placentation. The available evidence points to the relevance of these molecules as distinguishing markers of the various trophoblast lineages and as potential therapeutic targets in the management of malplacentation-mediated diseases.

Epiregulin promotes trophoblast epithelial-mesenchymal transition through poFUT1 and O-fucosylation by poFUT1 on uPA

Objectives

The transformation of cytotrophoblasts into mesenchymal‐like extravillous trophoblasts is necessary for successful embryo implantation, and the inadequate transformation may cause abortion. Epiregulin, which is a new growth factor, plays important roles in the reproductive processes. The glycosylation of many proteins in reproduction processes is critical. Protein O‐fucosyltransferase 1 (poFUT1) is the key enzyme for the biosynthesis of O‐fucosylation on the specific glycoproteins. Urokinase‐type plasminogen activator (uPA) contains O‐fucosylated domain on Thr¹⁸. However, the functions of epiregulin and poFUT1 in the trophoblast epithelial–mesenchymal transition (EMT) process, the regulatory mechanism of epiregulin on poFUT1 and the resulting O‐fucosylated uPA remain unclear.

Materials and methods

We employed ELISA and Western blot to detect serum levels of epiregulin and poFUT1 from non‐pregnancy women, pregnancy women and abortion patients. Using two trophoblast cell lines and a mouse pregnancy model, we investigated the underlying mechanisms of epiregulin and poFUT1 in trophoblast EMT process.

Results

Serum levels of epiregulin and poFUT1 were higher in pregnant women compared with non‐pregnant women, and their levels were significantly decreased in abortion patients compared with pregnant women. The results showed that epiregulin upregulated poFUT1 expression and increased O‐fucosylation on uPA, which further activated the PI3K/Akt signalling pathway, facilitating EMT behaviour of trophoblast cells and embryo implantation in the mouse pregnant model.

Conclusions

Level of epiregulin and poFUT1 is lower in abortion patients than early pregnancy women. Epiregulin promotes trophoblast EMT through O‐fucosylation on uPA catalysed by poFUT1. Epiregulin and poFUT1 may be suggested as the potential diagnostic biomarkers and useful treatment targets for abortion.

Down-regulated long non-coding RNA PVT1 contributes to gestational diabetes mellitus and preeclampsia via regulation of human trophoblast cells

OBJECTIVE

We aimed to explore the expression level and biological function of lncRNA PVT1 in human trophoblast cells.

METHODS

The expression levels of PVT1 in cancer cell lines, HTR8/SVneo cell, HUVEC cell, the maternal placenta of GDM patients, PE patients and normal pregnancy were detected by qRT-PCR. The cell culture, cell transfection, CCK-8 assay, flow cytometry, wound scratch assay and transwell were carried out to determine the effects of silencing and overexpression of PVT1 on the HTR8/SVneo trophoblast cell line. Nuclear and chromatin RNA fraction assay, RNA-sequencing, western blot and qRT-PCR were conducted to preliminarily explore possible mechanisms.

RESULTS

The relative PVT1 expression level in HTR-8/Svneo cells was higher compared to other cancer cells and HUVEC, and was lower in the GDM and PE placentas than in the normal placentas. The results showed that PVT1 knockdown notably inhibited the proliferation, migration and invasiveness abilities of trophoblast cells, and significantly promoted the apoptosis. Furthermore, overexpression of PVT1 showed the opposite results. We identified 105 differentially expressed genes after PVT1 knockdown, 23 were up-regulated and 82 were down-regulated. GO enrichment analysis and pathway enrichment analysis showed that the DEGs were closely related to the functional changes of trophoblast cells. Because of the enrichment of 7 DEGs and less Q value, PI3K/AKT pathway was prominent and attracted our attention. More importantly, we confirmed that knockdown of PVT1 obviously decreased AKT phosphorylation and decreased the expression of DEGs (GDPD3, ITGAV and ITGB8) while overexpression of PVT1 promoted the AKT phosphorylation and increased the expression of DEGs (GDPD3, ITGAV and ITGB8). PVT1 was primarily distributed in the nuclear compartment and also distributed in the cytoplasmic of HTR-8/Svneo cells.

CONCLUSIONS

This study provided the evidence that PVT1 played a vital role in trophoblast cells, and it is important for maintaining the normal physiological function of trophoblast cells. The PVT1 expression was lower in the GDM and PE placentas than the normal placentas, which might disrupt the function of trophoblast cells through PI3K/AKT pathway.

HGF regulate HTR-8/SVneo trophoblastic cells migration/invasion under hypoxic conditions through increased HIF-1α expression via MAPK and PI3K pathways

Hepatocyte growth factor (HGF) is reported to be down-regulated in pregnancy complications like intrauterine growth retardation and preeclampsia, which are associated with abnormal trophoblast migration/invasion. In this study, role of HGF and associated signaling pathways has been investigated in HTR-8/SVneo trophoblastic cells migration/invasion under normoxia (20% O₂) and hypoxia (2% O₂). HTR-8/SVneo cells exposed to hypoxia showed increase in migration and invasion as compared to cells incubated under normoxic conditions. The migration/invasion under both normoxic and hypoxic conditions was further enhanced after treatment with HGF. Subsequent to treatment with HGF, a significant increase in expression of MMP2 & MMP3 under normoxia and MMP1 & MMP9 under hypoxia was observed. Treatment of HTR-8/SVneo cells with HGF under hypoxia also led to decrease in TIMP1. Treatment of the cells with HGF led to activation of mitogen activated protein kinases (MAPK) and phosphatidylinositol 3-kinase (PI3K) signaling pathways. Inhibition of MAPK by U0126 and PI3K by LY294002 led to concomitant decrease in the HGF-mediated migration/invasion of HTR-8/SVneo cells. HGF treatment under hypoxia also led to a significant increase in hypoxia inducible factor (HIF-1α) expression. Additionally, inhibition of HIF-1α by siRNA led to decrease in HGF-mediated migration of HTR-8/SVneo cells under hypoxic conditions. Inhibition of HGF activated MAPK and PI3K signaling led to reduction in HIF-1α expression under hypoxia. In conclusion, HGF facilitates HTR-8/SVneo cell migration/invasion by activation of MAPK/PI3K signaling pathways and increased expression of MMPs. HIF-1α has a role in HGF-mediated increase in migration under hypoxic conditions.