Placental Chemokine Receptor D6 Is Functionally Impaired in Pre-Eclampsia

Reduced Brain Cortex Angiogenesis in the Offspring of the Preeclampsia-Like Syndrome

BACKGROUND

Children from pregnancies affected by preeclampsia have an increased risk of cognitive and behavioral alterations via unknown pathophysiology. We tested the hypothesis that preeclampsia generated reduced brain cortex angiogenesis in the offspring.

METHODS

The preeclampsia-like syndrome (PELS) mouse model was generated by administering the nitric oxide inhibitor NG-nitroarginine methyl ester hydrochloride. Confirmatory experiments were done using 2 additional PELS models. While in vitro analysis used mice and human brain endothelial cells exposed to serum of postnatal day 5 pups or umbilical plasma from preeclamptic pregnancies, respectively.

RESULTS

We report significant reduction in the area occupied by blood vessels in the motor and somatosensory brain cortex of offspring (postnatal day 5) from PELS compared with uncomplicated control offspring. These data were confirmed using 2 additional PELS models. Furthermore, circulating levels of critical proangiogenic factors, VEGF (vascular endothelial growth factor), and PlGF (placental growth factor) were lower in postnatal day 5 PELS. Also we found lower VEGF receptor 2 (KDR [kinase insert domain-containing receptor]) levels in mice and human endothelial cells exposed to the serum of postnatal day 5 PELS or fetal plasma of preeclamptic pregnancies, respectively. These changes were associated with lower in vitro angiogenic capacity, diminished cell migration, larger F-actin filaments, lower number of filopodia, and lower protein levels of F-actin polymerization regulators in brain endothelial cells exposed to serum or fetal plasma of offspring from preeclampsia.

CONCLUSIONS

Offspring from preeclampsia exhibited diminished brain cortex angiogenesis, associated with lower circulating VEGF/PlGF/KDR protein levels, impaired brain endothelial migration, and dysfunctional assembly of F-actin filaments. These alterations may predispose to structural and functional alterations in long-term brain development.

Role of necroptosis and immune infiltration in preeclampsia: novel insights from bioinformatics analyses

BACKGROUND

Preeclampsia (PE) is a serious pregnancy complication that can adversely affect the mother and fetus. Necroptosis is a recently discovered new form of programmed cell death involved in the pathological process of various pregnancy complications. Our study aimed to identify the necroptosis-related differentially expressed genes (NRDEGs), create a diagnosis model and related disease subtypes model based on these genes, and further investigate their relationship with immune infiltration.

METHODS

In this study, we identified NRDEGs by analyzing data from various databases, including Molecular Signatures, GeneCards, and Gene Expression Omnibus (GEO). Using minor absolute shrinkage and selection operator (LASSO) and logistic Cox regression analysis, we developed a novel PE diagnosis model based on NRDEGs. Furthermore, we developed PE subtype models using consensus clustering analysis based on key gene modules screened out by weighted correlation network analysis (WGCNA). Finally, we identified the difference in immune infiltration between the PE and control groups as well as between both PE subtypes by analyzing the immune cell infiltration across combined datasets and PE datasets.

RESULTS

Our study discovered that the necroptosis pathway was significantly enriched and active in PE samples. We identified nine NRDEGs that involved in this pathway, including BRAF, PAWR, USP22, SYNCRIP, KRT86, MERTK, BAP1, CXCL5, and STK38. Additionally, we developed a diagnostic model based on a regression model including six NRDEGs and identified two PE subtypes: Cluster1 and Cluster2, based on key module genes. Furthermore, correlation analysis showed that the abundance of immune cell infiltration was related to necroptosis genes and PE disease subtypes.

CONCLUSION

According to the present study, necroptosis is a phenomenon that occurs in PE and is connected to immune cell infiltration. This result suggests that necroptosis and immune-related factors may be the underlying mechanisms of PE pathophysiology. This study opens new avenues for future research into PE's pathogenesis and treatment options.

Enoxaparin Increases D6 Receptor Expression and Restores Cytoskeleton Organization in Trophoblast Cells from Preeclampsia

D6 is a scavenger receptor for CC chemokines expressed in the human placenta. It prevents excessive leukocyte tissue infiltration by internalizing chemokines through cytoskeleton-dependent intracellular transport. In preeclampsia (PE), the D6 receptor is overexpressed in trophoblast cells, but functionally impaired, due to cytoskeleton destructuring. Low molecular weight heparin (LMWH) represents a potential treatment for PE based on its anti-thrombotic and anti-inflammatory properties. Here, we investigated the effect of enoxaparin on D6 expression, and cytoskeleton organization primary cytotrophoblast cell cultures were obtained from the placentae of women with PE (n = 9) or uncomplicated pregnancy (n = 9). We demonstrated that enoxaparin is able to (i) increase D6 expression, and (ii) improve cytoskeletal fiber alignment in trophoblast cells from PE patients.

The Role of Atypical Chemokine Receptor D6 (ACKR2) in Physiological and Pathological Conditions; Friend, Foe, or Both?

Chemokines exert crucial roles in inducing immune responses through ligation to their canonical receptors. Besides these receptors, there are other atypical chemokine receptors (ACKR1–4) that can bind to a wide range of chemokines and carry out various functions in the body. ACKR2, due to its ability to bind various CC chemokines, has attracted much attention during the past few years. ACKR2 has been shown to be expressed in different cells, including trophoblasts, myeloid cells, and especially lymphoid endothelial cells. In terms of molecular functions, ACKR2 scavenges various inflammatory chemokines and affects inflammatory microenvironments. In the period of pregnancy and fetal development, ACKR2 plays a pivotal role in maintaining the fetus from inflammatory reactions and inhibiting subsequent abortion. In adults, ACKR2 is thought to be a resolving agent in the body because it scavenges chemokines. This leads to the alleviation of inflammation in different situations, including cardiovascular diseases, autoimmune diseases, neurological disorders, and infections. In cancer, ACKR2 exerts conflicting roles, either tumor-promoting or tumor-suppressing. On the one hand, ACKR2 inhibits the recruitment of tumor-promoting cells and suppresses tumor-promoting inflammation to blockade inflammatory responses that are favorable for tumor growth. In contrast, scavenging chemokines in the tumor microenvironment might lead to disruption in NK cell recruitment to the tumor microenvironment. Other than its involvement in diseases, analyzing the expression of ACKR2 in body fluids and tissues can be used as a biomarker for diseases. In conclusion, this review study has tried to shed more light on the various effects of ACKR2 on different inflammatory conditions.

Abnormal uterine inflammation in obstetric syndromes: molecular insights into the role of chemokine decoy receptor D6 and inflammasome NLRP3

The adaptation of the uterine environment into a favorable immunological and inflammatory milieu is a physiological process needed in normal pregnancy. A uterine hyperinflammatory state, whether idiopathic or secondary to hormonal or organic uterine disorders (polycystic ovary syndromes, endometriosis/adenomyosis and fibroids), negatively influences the interactions between decidua and trophoblast, early in gestation, and between chorion and decidua later in pregnancy. Abnormal activation of uterine inflammatory pathways not only contributes to the pathogenesis of the obstetric syndromes, i.e. recurrent pregnancy loss (RPL), pre-term delivery (PTD) and pre-eclampsia (PE), but also to correlates with severity. In this review, we summarize recent advances in the knowledge of uterine molecular mechanisms of inflammatory modulation in normal pregnancy and obstetric syndromes (RPL, PTD and PE). In particular, we focus on two regulators of uterine/placental inflammation: the NLRP3 inflammasome and the chemokines decoy receptor D6. We performed comprehensive review of the literature in PubMed and Google Scholar databases from 1994 to 2018. The available evidence suggests that: (i) the expression of inflammasome NLRP3 is increased in the endometrium of women with unexplained RPL, in the chorioamniotic membranes of women with PTL and in the placenta of women with PE; (ii) there is a role for abnormal expression and function of D6 decoy receptor at the feto-maternal interface in cases of RPL and PTD and (iii) the function of placental D6 decoy receptor is impaired in PE. A wider comprehension of the inflammatory molecular mechanisms involved in the pathogenesis of the obstetric syndromes might lead to the identification of new potential therapeutic targets.

Specific inflammatory profile in each pregnancy complication: A comparative study

PROBLEM

Pre-eclampsia (PE), preterm birth (PTB) and intra-uterine growth restriction (IUGR) affect 5%-12% of pregnancies. They have been associated with placental inflammation, although the detection of inflammatory mediators in the maternal circulation is still controversial. Our goal was to determine the inflammatory changes occurring in the second part of pregnancy to identify profiles distinguishing pathological pregnancies from each other.

METHOD OF STUDY

We performed a nested case-control study of 200 women randomly selected from a cohort recruited at the CHU de Quebec-Universite Laval, Quebec, Canada. Women with uncomplicated term pregnancy (CTRL); PE (severe or not); PTB or IUGR (N = 50/each) were included. Plasma samples, obtained from the late second trimester and at delivery, were analysed for over 30 selected mediators (including cytokines/alarmins), by multiplex, ELISA or specific assays. Demographic and obstetrical information were obtained for classification.

RESULTS

In CTRL, we observed significant differences between 2nd trimester and delivery, with increased levels of inflammatory mediators (ex. MCP-1, IL-6), supporting an inflammatory profile towards term. Increased levels of IL-6, CXCL10 and CRP were observed in PE as compared to CTRL. In PTB, we observed increased CXCL9 in 2nd trimester and decreased progesterone at delivery. In IUGR, increased HMGB1 and IL-1α were observed only in the 2nd trimester.

CONCLUSIONS

Our work showed significant inflammatory changes in uncomplicated pregnancies towards delivery, supporting that normal delivery is pro-inflammatory, although not to the same extent as in pathological pregnancies. Inflammatory profiles are specific to each pregnancy complication which may help to understand the contribution of inflammation to the clinical presentation of these conditions.

Per- and Polyfluoroalkyl Substances Differentially Inhibit Placental Trophoblast Migration and Invasion In Vitro

Per- and polyfluoroalkyl substances (PFAS) are used as industrial surfactants and chemical coatings for household goods such as Teflon. Despite regulatory efforts to phase out legacy PFAS, they remain detectable in drinking water throughout the United States. This is due to the stability of legacy PFAS and the continued use of replacement compounds. In humans, PFAS have been detected in placenta and cord blood and are associated with low birth weight and preeclampsia risk. Preeclampsia is a leading cause of maternal mortality and is driven by insufficient endometrial trophoblast invasion, resulting in poor placental blood flow. PFAS alter invasion of other cell types, but their impact on trophoblasts is not understood. We therefore assessed the effects of PFAS on trophoblast migration, invasion, and gene expression in vitro. Trophoblast migration and invasion were assessed using a modified scratch assay in the absence or presence of Matrigel, respectively. Treatment with perfluorooctanoic sulfate (PFOS), perfluorooctanoic acid (PFOA), and GenX (1000 ng/ml) each decreased trophoblast migration over 24 h. However, only GenX (1000 ng/ml) significantly inhibited trophoblast invasion. Treatment with PFOS, PFOA, and GenX also decreased trophoblast expression of chemokines (eg, CCL2), chemokine receptors (eg, CCR4), and inflammatory enzymes (eg, ALOX15) involved in migration. Inhibition of chemokine receptors with pertussis toxin (10 ng/ml), a G-protein inhibitor, inhibited trophoblast migration similar to the PFAS. Taken together, PFAS decrease trophoblast migration, invasion, and inflammatory signaling. By understanding the mechanisms involved, it may be possible to identify the biological and exposure factors that contribute to preeclampsia.

Expression of ACKR2 in placentas from different types of preeclampsia

OBJECTIVE

The purpose of this study was to investigate the expression of atypical chemokine receptor 2 (ACKR2, D6) in different types of preeclampsia (PE) and its effects on trophoblast proliferation and apoptosis.

METHODS

The subjects were divided into four groups: early-onset PE group (EOPE, n = 30), late-onset PE group (LOPE, n = 30), preterm birth group (PB, n = 30), and normal group (N, n = 30). The expression of ACKR2 in placentas was evaluated using immunohistochemistry, qRT-PCR, and Western blot. The trophoblast cell line JAR was cultured to detect the expression of ACKR2 after simulating hypoxic conditions with cobalt chloride (CoCl₂). The effects on cell proliferation, apoptosis, and expression of the chemokine CCL2 were analyzed after silencing ACKR2 with siRNA.

RESULTS

ACKR2 was decreased in placentas of EOPE and PB groups at the protein and mRNA level，compared to the normal group. No statistical differences were found between EOPE and PB groups, or between LOPE and normal groups. In our in vitro work, we found that the expression of ACKR2 decreased after treatment with 150 μmol/L, 200 μmol/L, and 250 μmol/L of CoCl₂. After ACKR2 was silenced, the degree of cellular proliferation decreased, while apoptosis and CCL2 expression increased.

CONCLUSION

The changes of ACKR2 expression in placentas of PE may be related to gestational weeks. Hypoxia inhibits the expression of ACKR2 in placentas. Abnormal expression of ACKR2 in PE may lead to dysfunction of trophoblast, and ACKR2 is an essential player in the immunoregulation of the placental chemokine CCL2.