Human cytomegalovirus inhibits the proliferation and invasion of extravillous cytotrophoblasts via Hippo-YAP pathway

Background Human cytomegalovirus (HCMV) infection in utero is very common during pregnancy, which can lead to adverse outcomes in both pregnancy and progeny, but its pathogenesis has not been fully clarified. The decrease of extravillous cytotrophoblasts (EVT) invasion is an essential pathophysiological process of some pregnancy complications. Hippo-YAP signaling pathway plays an important role in regulating cell proliferation and apoptosis. However, whether YAP is involved in HCMV uterine infection remains to be studied. Methods The primary EVT was cultured and infected by the HCMV strain AD169 virus in vitro. Immunofluorescence staining of HCMVpp65 antigen was conducted afterward to confirm the establishment of an infection model. The optimal virus infection dose was determined by the EVT proliferation status in vitro. Real-time PCR was performed to examine the mRNA level of major genes involved in the Hippo pathway in EVT after HCMV infection. The effect of HCMV on the expression of YAP protein in EVT was evaluated by Immunofluorescence staining and Western blot. An in vitro cell invasion assay was carried out to analyze the influence of HCMV on EVT invasion. The changes of EVT invasion was accessed by establishing YAP silencing and over-expression models using YAP1 specific siRNA and plasmid pcDH. Results The optimal HCMV infection dose was 282.5TCID50/ml. Compared to the control group, the infection of HCMV significantly reduced the mRNA expression of Mst1, Mst2, SAV, Lats1, Lats2, Mob1, YAP1, TAZ, TEAD1-4 genes and YAP protein expression in the Hippo-YAP pathway. HCMV infection also decreased the EVT invasion. In non-infected EVT, the number of transmembrane EVT cells was significantly reduced when YAP1 gene was silenced, while it was significantly increased when YAP1 gene was over-expressed. In the HCMV-infected EVT, the number of transmembrane EVT cells significantly increased when over-expressed and eventually recovered to the level of NC. Conclusions HCMV may decrease EVT invasion by inhibiting the expression of mRNA and protein of YAP in the Hippo-YAP signaling pathway. HCMV eventually reduces the invasion ability of EVT by inhibiting multiple genes in the Hippo-YAP signaling pathway, especially inhibiting YAP which serves as the downstream effector.

Evolutionary transcriptomics implicates HAND2 in the origins of implantation and regulation of gestation length

The developmental origins and evolutionary histories of cell types, tissues, and organs contribute to the ways in which their dysfunction produces disease. In mammals, the nature, development and evolution of maternal-fetal interactions likely influence diseases of pregnancy. Here we show genes that evolved expression at the maternal-fetal interface in Eutherian mammals play essential roles in the evolution of pregnancy and are associated with immunological disorders and preterm birth. Among these genes is HAND2, a transcription factor that suppresses estrogen signaling, a Eutherian innovation allowing blastocyst implantation. We found dynamic HAND2 expression in the decidua throughout the menstrual cycle and pregnancy, gradually decreasing to a low at term. HAND2 regulates a distinct set of genes in endometrial stromal fibroblasts including IL15, a cytokine also exhibiting dynamic expression throughout the menstrual cycle and gestation, promoting migration of natural killer cells and extravillous cytotrophoblasts. We demonstrate that HAND2 promoter loops to an enhancer containing SNPs implicated in birth weight and gestation length regulation. Collectively, these data connect HAND2 expression at the maternal-fetal interface with evolution of implantation and gestational regulation, and preterm birth.

Temporal placental genome wide expression profiles reflect three phases of utero-placental blood flow during early to mid human gestation

During early human placental development, extravillous cytotrophoblasts (EVT) invade the uterine vasculature to sequester a maternal blood supply. The impact of this on placental gene expression has not been established for normal pregnancy. Using RNA sequencing, we profiled placental chorionic villous tissues from 96 pregnancies at 6-23 weeks of gestation. We identified 1,048 genes that were differentially expressed between 6-10 weeks’ and 11-23 weeks’ of gestation. These are predominantly genes that are enriched in transcription factor signalling, inflammatory response and cell adhesion. Using a co-expression network and gene set enrichment analyses, we reveal three distinct phases of gene expression coincident with phases of maternal blood flow to the placenta that impact immune function and are likely driven by oxygen tension, potentially in a sex-specific manner. These data represent a comprehensive transcriptional profile of early placental development and point to significant environmental, genetic and regulatory triggers that drive gene expression.

Infection of Placental Extravillous Cytotrophoblasts with Human Cytomegalovirus Causes a Treg/Th17 Imbalance at the Maternal–Fetal Interface

This paper aimed to evaluate whether human cytomegalovirus (HCMV) infection in extravillous cytotrophoblasts (EVT) could shift the balance between regulatory T (Treg) and T-helper type 17 (Th17) cells in vitro. In this study, primary EVT isolated from first trimester placental tissues were infected with HCMV, and conditional media were harvested after cultivation for 72 h. T lymphocytes were cultured in the presence or absence of HCMV-infected conditional media. The frequencies of Th17 or Treg cells from HCMV group were significantly lower or higher than those from the control group, with the expression of corresponding key cytokines at both messenger ribonucleic acid and secretion levels, respectively. The ratio of Treg to Th17 cells was significantly lower in HCMV group than that in control group ( P < 0.01). In conclusion, tiled Th17/Treg balance at maternal–fetal interface exists after HCMV infection.

ANXA4 promotes trophoblast invasion via the PI3K/Akt/eNOS pathway in preeclampsia

The inadequate trophoblast invasion is associated with the development of preeclampsia (PE). Considering that annexin A4 (ANXA4) enhances tumor invasion, we aimed to explore the functional role of ANXA4 in trophoblast cells and to examine the underlying mechanism. ANXA4 expression in PE placentas was analyzed using immunohistochemistry and Western blotting. Cell proliferation, invasion, and apoptosis were determined using a MTT assay, Transwell assay, and flow cytometry, respectively. The expression levels of matrix metalloproteinase (MMP)-2, MMP-9, phosphoinositide 3-kinase (PI3K), Akt, phosphorylated (p)-Akt, and phosphorylated endothelial nitric oxide synthase (p-eNOS) were detected by Western blotting. Placentas were prepared for pathological examination using hematoxylin and eosin staining and apoptosis determination using the TUNEL method. Expression of ANXA4, PI3K, p-Akt and p-eNOS was downregulated in human PE placentas and PE placenta-derived extravillous cytotrophoblasts (EVCTs). Furthermore, ANXA4 overexpression promoted cell proliferation and invasion, inhibited cell apoptosis, and upregulated protein expression of PI3K, p-Akt, and p-eNOS in human trophoblast cells HTR-8/SVneo and JEG-3. By contrast, ANXA4 knockdown exerted the opposite effects. Furthermore, inhibition of the PI3K/Akt pathway by LY294002 abrogated the ANXA4 overexpression-mediated effects on trophoblast behavior. Furthermore, eNOS knockdown abrogated the ANXA4 overexpression-induced promotion of cell invasion and MMP2/9 expression. Additionally, in N-nitro-l-arginine methyl ester (l-NAME)-induced PE rats, ANXA4 overexpression alleviated PE progression, accompanied by an increase in expression of PI3K, p-Akt, and p-eNOS in rat placentas. Our findings demonstrate that ANXA4 expression is downregulated in PE. ANXA4 may promote trophoblast invasion via the PI3K/Akt/eNOS pathway.

AP-1 Transcription Factors c-FOS and c-JUN Mediate GnRH-Induced Cadherin-11 Expression and Trophoblast Cell Invasion

GnRH is expressed in first-trimester human placenta and increases cell invasion in extravillous cytotrophoblasts (EVTs). Invasive phenotypes have been reported to be regulated by transcription factor activator protein 1 (AP-1) and mesenchymal cadherin-11. The aim of our study was to investigate the roles of AP-1 components (c-FOS/c-JUN) and cadherin-11 in GnRH-induced cell invasion in human EVT cells. Phosphorylated c-FOS and phosphorylated c-JUN were detected in the cell column regions of human first-trimester placental villi by immunohistochemistry. GnRH treatment increased c-FOS, c-JUN, and cadherin-11 mRNA and protein levels in immortalized EVT (HTR-8/SVneo) cells. Moreover, GnRH treatment induced c-FOS and c-JUN protein phosphorylation and nuclear accumulation. Pretreatment with antide, a GnRH antagonist, attenuated GnRH-induced cadherin-11 expression. Importantly, basal and GnRH-induced cadherin-11 expression and cell invasion were reduced by small interfering RNA-mediated knockdown of c-FOS, c-JUN, and cadherin-11 in HTR-8/SVneo cells. Our results suggest that GnRH induces the expression and phosphorylation of the AP-1 transcription factors c-FOS and c-JUN in trophoblast cells, which contributes to GnRH-induced elevation of cadherin-11 expression and cell invasion.

Immunomodulatory Properties of HLA-G in Infectious Diseases

HLA-G is a nonclassical major histocompatibility complex molecule first described at the maternal-fetal interface, on extravillous cytotrophoblasts. Its expression is restricted to some tissues in normal conditions but increases strongly in pathological conditions. The expression of this molecule has been studied in detail in cancers and is now also beginning to be described in infectious diseases. The relevance of studies on HLA-G expression lies in the well known inhibitory effect of this molecule on all cell types involved in innate and adaptive immunity, favoring escape from immune control. In this review, we summarize the features of HLA-G expression by type of infections (i.e, bacterial, viral, or parasitic) detailing the state of knowledge for each pathogenic agent. The polymorphism, the interference of viral proteins with HLA-G intracellular trafficking, and various cytokines have been described to modulate HLA-G expression during infections. We also discuss the cellular source of HLA-G, according to the type of infection and the potential role of HLA-G. New therapeutic approaches based on synthetic HLA-G-derived proteins or antibodies are emerging in mouse models of cancer or transplantation, and these new therapeutic tools may eventually prove useful for the treatment of infectious diseases.