Expression, regulation and functional characterization of matrix metalloproteinase-3 of human trophoblast

Matrix metalloproteinase-3 in preeclamptic and normotensive pregnancies complicated by foetal growth restriction

The aim of the present study was to assess the interrelationships between the level of matrix metalloproteinase-3 in the blood serum of pregnant women and the occurrence of pregnancy complications in the form of foetal growth restriction, idiopathic or in the course of preeclampsia.

Methods

A total of 245 patients were included in the study. 65 of them are normotensive patients with idiopathic foetal growth restriction (FGR group). 115 women were diagnosed with severe preeclampsia. In the group of women with preeclampsia, there were 51 patients with adequate for gestational age foetal growth and 64 patients with the foetal growth restriction in the course of severe preeclampsia. The control group consisted of 65 healthy patients with normal pregnancy course, with no cardiovascular disorders at the present and in the history, normal blood pressure and normal intrauterine foetal growth. Matrix metalloproteinase-3 (MMP-3) in maternal circulation were determined by ELISA method.

Results

In our studies, we observed elevated levels of matrix metalloproteinase-3 in preeclamptic women with pregnancies complicated by FGR and significantly lower in the group of normotensive women with idiopathic FGR. The mean values of MMP-3 were 33.50 ± 65.74 ng/mL [Median (min-max) 19.19 (2.05-454.53)] in the Control group, 21.22 ± 23.28 ng/mL [Median (min-max) 16.39 (3.45-156.29)] in the FGR group, 35.96 ± 46.14 ng/mL [Median (min-max) 25.21 (4.16-253.05)] in the P group and 52.81 ± 61.61 ng/mL [Median (min-max) 32.83 (5.06-314.14)] in preeclamptic women with FGR (group PI) respectively.The assessment of MMP-3 in the serum of women with pregnancies complicated by intrauterine foetal growth restriction with normal values of blood pressure and in the group of preeclamptic patients in relation to healthy pregnant women with uncomplicated pregnancies and in relation to preeclamptic patients with normal intrauterine foetal growth is the novelty of this study. Such a strict definition of each research group seems to allow for the assessment of each pregnancy complication separately.

Conclusion

It seems that higher levels of MMP-3 in preeclamptic women may suggest the need for observation towards the risk of lower birth weight of newborns. This necessitates further research and a better integration in the clinical practice.

Transcriptomic mapping of the metzincin landscape in human trophoblasts

The metzincin family of metalloproteases coordinates tissue developmental processes through regulation of growth factor availability, receptor signaling, and cell-cell/cell-matrix adhesion. While roles for select metzincins in controlling trophoblast functions in human placental development have been described, a comprehensive understanding of metzincin dynamics during trophoblast differentiation is lacking. To address this knowledge gap, single cell transcriptomic datasets derived from first trimester chorionic villi and decidua were used to decipher metzincin expression profiles and kinetics in diverse cell types within the utero-placental interface. Further, specific protease-substrate interactions within progenitor trophoblasts were examined to better define the progenitor niche. Within the uterine-placental compartment, 43 metzincin proteases were expressed across 15 cell-type clusters. Metzincin subgroups expressed in placental trophoblasts, placental mesenchymal cells, uterine stromal, and immune cells included multiple matrix metalloproteases (MMPs), a disintegrin and metalloproteases (ADAMs), a disintegrin and metalloproteases with thrombospondin repeats (ADAMTSs), pappalysins, and astacins. Within the trophoblast compartment, eight distinct trophoblasts states were identified: four cytotrophoblast (CTB), one syncytiotrophoblast precursor (SCTp), two column CTB (cCTB), and one extravillous trophoblast (EVT). Within these states 7 MMP, 8 ADAM, 4 ADAMTS, 2 pappalysin, and 3 astacin proteases were expressed. Cell trajectory modeling shows that expression of most (19/24) metzincins increase during EVT differentiation, though expression of select metalloproteases increase along the villous pathway. Eleven metzincins (ADAM10, -17, MMP14, -15, -19, -23B, ADAMTS1, -6, -19, TLL-1, -2) showed enrichment within CTB progenitors, and analysis of metzincin-substrate interactions identified ∼150 substrates and binding partners, including FBN2 as an ADAMTS6-specific substrate. Together, this work characterizes the metzincin landscape in human first trimester trophoblasts and establishes insight into the roles specific proteases perform within distinct trophoblast niches and across trophoblast differentiation. This resource serves as a guide for future investigations into the roles of metzincin proteases in human placental development.

An old friend with a new face: YB-1 and its role in healthy pregnancy and pregnancy-associated complications

By promoting tissue invasion, cell growth and angiogenesis, the Y-box binding protein (YB-1) became famous as multifunctional oncoprotein. However, this designation is telling only part of the story. There is one particular time in life when actual tumorigenic-like processes become undoubtedly welcome, namely pregnancy. It seems therefore reasonable that YB-1 plays also a crucial role in reproduction, and yet this biological aspect of the cold-shock protein has been overlooked for many years. To overcome this limitation, we would like to propose a new perspective on YB-1 and emphasize its pivotal functions in healthy pregnancy and pregnancy-related complications. Moreover, we will discuss findings obtained from cancer research in the light of reproductive events to elucidate the importance of YB-1 at the feto-maternal interface.

Matrix Metalloproteinase 3: A Promoting and Destabilizing Factor in the Pathogenesis of Disease and Cell Differentiation

Cells must alter their expression profiles and morphological characteristics but also reshape the extracellular matrix (ECM) to fulfill their functions throughout their lifespan. Matrix metalloproteinase 3 (MMP-3) is a member of the matrix metalloproteinase (MMP) family, which can degrade multiple ECM components. MMP-3 can activate multiple pro-MMPs and thus initiates the MMP-mediated degradation reactions. In this review, we summarized the function of MMP-3 and discussed its effects on biological activities. From this point of view, we emphasized the positive and negative roles of MMP-3 in the pathogenesis of disease and cell differentiation, highlighting that MMP-3 is especially closely involved in the occurrence and development of osteoarthritis. Then, we discussed some pathways that were shown to regulate MMP-3. By writing this review, we hope to provide new topics of interest for researchers and attract more researchers to investigate MMP-3.

Modeling human peri-implantation placental development and function†

It is very difficult to gain a better understanding of the events in human pregnancy that occur during and just after implantation because such pregnancies are not yet clinically detectable. Animal models of human placentation are inadequate. In vitro models that utilize immortalized cell lines and cells derived from trophoblast cancers have multiple limitations. Primary cell and tissue cultures often have limited lifespans and cannot be obtained from the peri-implantation period. We present here two contemporary models of human peri-implantation placental development: extended blastocyst culture and stem-cell derived trophoblast culture. We discuss current research efforts that employ these models and how such models might be used in the future to study the "black box" stage of human pregnancy.

Altered expression of ADM and ADM2 by hypoxia regulates migration of trophoblast and HLA-G expression†

Preeclampsia (PE) is a placental disorder caused by endothelial dysfunction via trophoblast inadequate invasion activity. Adrenomedullin (ADM) and ADM2 are multifunctional peptides that can support vascular activity and placental growth. However, correlation between ADMs and trophoblast functions is currently unclear. The objective of this study was to analyze changes in expression of ADMs in placenta and HTR-8/SVneo trophoblast cells under hypoxia and their effects on invasion activity of trophoblast cells and expression of HLA-G. In placental tissues of PE, expression levels of ADM and HLA-G were significantly increased (P < 0.05) whereas expression of ADM2 was decreased compared to that in normal term placenta. Under hypoxia, expression levels of ADM, ADM2, and HLA-G and invasion ability of trophoblast cells were increased in hypoxia-inducible factor-1 (HIF-1α)- dependent manner (P < 0.05). Treatment with ADMs agonists reduced HIF-1α activity whereas enhanced invasion ability under hypoxia. However, they were not changed after cotreatment of ADMs and HIF-1α inhibitor, YC-1, although expression levels of invasion-related genes MMP2, MMP9, and Rac1 were altered (P < 0.05). ADMs also increased HLA-G expression under normoxia whereasADM2 or cotreatment of ADMs under hypoxia attenuated HLA-G expression (P < 0.05). Our findings demonstrate that altered expression of ADMs plays a critical role in placental physiology, especially in trophoblast invasion and immune-modulation under hypoxia.

Multiplex Analysis of Circulating Maternal Cardiovascular Biomarkers Comparing Preeclampsia Subtypes

Preeclampsia, a hypertensive pregnancy disorder, links to increased long-term maternal cardiovascular disease (CVD). The risk is further increased with early-onset preeclampsia (EPE) and delivery of a growth-restricted child. We hypothesized that circulating biomarkers associated with CVD risk differed between preeclampsia subtypes and controls. We compared EPE; n=37, delivery <week 34, late-onset preeclampsia (LPE); n=29, delivery ≥week 34, and normotensive controls (n=49) using Olink Proseek multiplex CVD I assay (targeting 92 biomarkers). We stratified analysis to uteroplacental spiral artery acute atherosis presence in preeclampsia patients, sharing morphological similarities with atherosclerosis. We found 47 CVD-related biomarkers differing between the groups, 42 markers between normotensive controls and EPE, 28 markers between normotensive controls and LPE, and 9 markers between EPE and LPE. Among these 9 markers, ST2 (ST2 protein), MMP (matrix metalloproteinase) 1, MMP3, and fractalkine (CX3CL1) were uniquely dysregulated in EPE. Principal component (PC) analysis of the differing markers identified 4 clusters (named PC1-PC4) that largely separated the preeclampsia and control groups as well as pregnancies with low and high circulating PlGF (placental growth factor). The combination of the single markers PlGF, ST2, MMP1, MMP3, and CX3CL1 had a high discriminatory property to differentiate between EPE and LPE. Preeclampsia with acute atherosis or with fetal growth restriction could be differentiated by Olink biomarkers as compared with preeclampsia without these features. We identified specific CVD-related biomarkers in pregnancy depending on preeclampsia subtypes and uteroplacental acute atherosis. Assessment of these pregnancy measured biomarkers' relation to long-term cardiovascular dysfunction and hard end points is warranted.

Differential processing of high-molecular-weight kininogen during normal pregnancy

RATIONALE

Studies identified kininogen as a potential biomarker of preeclampsia, a major cause of adverse maternal outcomes. High-molecular-weight kininogen (HK) and its activated form participate in numerous pathways associated with establishing and maintaining pregnancy. However, dynamic changes in HK and naturally occurring HK-derived peptides during the natural course of pregnancy are largely unknown.

METHODS

Longitudinal serum samples during the course of normal pregnancy (trimesters T1, T2, T3) from 60 pregnant women were analyzed by western blot with an anti-HK antibody. Circulating peptides in longitudinal serum specimens derived from 50 participants were enriched using nanoporous silica thin films. Peptides were identified by liquid chromatography/tandem mass spectrometry (LC/MS/MS) and database searching. Relative quantification was performed using MaxQuant and in-house scripts. Normality was evaluated by either ANOVA or Friedman tests with p < 0.05 for statistical significance.

RESULTS

Western blotting revealed that HK significantly decreased during normal pregnancy (T1 vs T2, p < 0.05; T1 vs T3, p < 0.0001). A 100 kDa intermediate increased during pregnancy (T1 vs T2, p < 0.005; T1 vs T3, p < 0.01). Moreover, the heavy chain (T1 vs T2, p < 0.0001; T1 vs T3, p < 0.0001; T2 vs T3, p < 0.01) and light chain (T1 vs T2, p < 0.0001; T1 vs T3, p < 0.0001; T2 vs T3, p < 0.05) significantly increased during pregnancy. LC/MS/MS analysis identified 180 kininogen-1 peptides, of which 167 mapped to domain 5 (D5). Seventy-three peptides with ten or more complete data sets were included for further analysis. Seventy peptides mapped to D5, and 3, 24, and 43 peptides showed significant decrease, no trend, and significant increase, respectively, during pregnancy.

CONCLUSIONS

This study demonstrates dynamic changes in HK and naturally occurring HK-derived peptides during pregnancy. Our study sheds light on the gestational changes of HK and its peptides for further validation of them as potential biomarkers for pregnancy-related complications.

Brominated diphenyl ether-47 differentially regulates cellular migration and invasion in a human first trimester trophoblast cell line

Polybrominated diphenyl ethers (PBDEs) are flame retardant compounds detected in human placenta and linked to adverse pregnancy outcomes. Impaired trophoblast migration and invasion during early pregnancy have been implicated as potential mechanisms of pregnancy disorders. The present study investigated the effect of BDE-47, a prevalent PBDE congener, on cell migration, invasion, and matrix metalloproteinase (MMP) expression in a human first trimester extravillous trophoblast cell line, HTR-8/SVneo. BDE-47 stimulated cell migration in HTR-SV/neo cells while decreasing invasion of cells into Matrigel. In addition, BDE-47 led to differential expression of MMP-1, -2, -3, and -9 at protein and mRNA levels. In summary, BDE-47 differentially regulated cellular migration and invasion with divergent changes in MMP expression in trophoblasts. Because proper regulation of trophoblast migration and invasion is critical for placental development and function, further research is warranted to determine if exposure to PBDEs disrupts trophoblast functions with increased risk for adverse pregnancy outcomes.

SPARCL1 impedes trophoblast migration and invasion by down-regulating ERK phosphorylation and AP-1 production and altering EMT-related molecule expression

INTRODUCTION

Embryo implantation depends on trophoblast cells migration and invasion. Abnormal function of trophoblast cells could result in many pregnancy complications. Secreted protein acidic and rich in cysteine like-1 (SPARCL1) has been reported to inhibit cell migration and tumor invasion. This study aimed to explore the role of SPARCL1 in trophoblast functions.

METHODS

Villous specimens were obtained from 31 women with spontaneous abortion and 31 women with normal early pregnancy to determine the expression of SPARCL1. HTR8/SVneo cells and JAR cells were transfected with pIRES2-EGFP-SPARCL1 vectors and control vectors. The proliferation assay and scratch-wound assay were performed. Quantitative polymerase chain reaction (qPCR) and western blotting were performed to assess epithelial mesenchymal transition (EMT)-related molecules including MMP2, MMP3, N-cadherin, E-cadherin and vimentin. Extracellular signal-regulated kinase (ERK) phosphorylation activity and AP-1 expression in HTR8/SVneo cells following multi-scratching were detected using above assays.

RESULTS

The mRNA and protein levels of SPARCL1 were significantly higher in the abortion group than in the normal pregnancy group. After transfection, there was no difference of cell viability between the SPARCL1-overexpression group and control vector group. However, the migration distance and area were reduced and the abundances of EMT related molecules were changed by SPARCL1 overexpression when compared with controls. Lower ERK phosphorylation activity and decreased Fos and Jun expressions were noted at high level of SPARCL1.

CONCLUSION

Restrained migration and invasion were noted in trophoblast cells with SPARCL1 overexpression, which might affect embryo implantation and placenta development. It could be involved in the pathogenesis of spontaneous abortion.

New Insights into the Process of Placentation and the Role of Oxidative Uterine Microenvironment

For a successful pregnancy to occur, a predecidualized receptive endometrium must be invaded by placental differentiated cells (extravillous trophoblast cells (EVTs)) and, at the same time, continue decidualization. EVT invasion is aimed at anchoring the placenta to the maternal uterus and ensuring local blood supply increase necessary to provide normal placental and foetal development. The first is achieved by migrating through the maternal endometrium and deeper into the myometrium, while the second by transforming uterine spiral arteries into large vessels. This process is a tightly regulated battle comprising interests of both the mother and the foetus. Invading EVTs are required to perform a scope of functions: move, adhere, proliferate, differentiate, interact, and digest the extracellular matrix (ECM); tolerate hypoxia; transform the maternal spiral arteries; and die by apoptosis. All these functions are modulated by their surrounding microenvironment: oxygen, soluble factors (e.g., cytokines, growth factors, and hormones), ECM proteins, and reactive oxygen species. A deeper comprehension of oxidative uterine microenvironment contribution to trophoblast function will be addressed in this review.

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.

Increased placental expression of Placental Protein 5 (PP5) / Tissue Factor Pathway Inhibitor-2 (TFPI-2) in women with preeclampsia and HELLP syndrome: Relevance to impaired trophoblast invasion?

INTRODUCTION

Placental Protein 5 (PP5)/Tissue Factor Pathway Inhibitor-2 (TFPI-2) is an extracellular matrix-associated protein mainly expressed by the syncytiotrophoblast that may regulate trophoblast invasion. Our aim was to study placental PP5/TFPI-2 expression and its relation to placental pathology in various forms of preeclampsia and HELLP syndrome.

METHODS

Placental and maternal blood specimens were collected at the time of delivery from the same women in the following groups: 1) early controls; 2) early preeclampsia; 3) early preeclampsia with HELLP syndrome; 4) late controls; and 5) late preeclampsia. After histopathological examination, placental specimens were immunostained with polyclonal anti-PP5/TFPI-2 antibody on Western blot and tissue microarray immunohistochemistry. Placental PP5/TFPI-2 immunoscores were assessed manually and with a semi-automated method. Maternal sera were immunoassayed for PP5/TFPI-2.

RESULTS

PP5/TFPI-2 was localized to the cytoplasm of syncytiotrophoblast. Manual and semi-automated PP5/TFPI-2 immunoscores were higher in early preeclampsia with or without HELLP syndrome but not in late preeclampsia than in respective controls. In patients with preeclampsia, the correlation of placental PP5/TFPI-2 expression with maternal vascular malperfusion score of the placenta was positive while it was negative with birthweight and placental weight. Maternal serum PP5/TFPI-2 concentration was higher in early preeclampsia and it tended to be higher in early preeclampsia with HELLP syndrome than in early controls.

DISCUSSION

Our findings suggest that an increased placental PP5/TFPI-2 expression may be associated with abnormal placentation in early preeclampsia, with or without HELLP syndrome.

Regulation of Placental Extravillous Trophoblasts by the Maternal Uterine Environment

During placentation invasive extravillous trophoblasts (EVTs) migrate into the maternal uterus and modify its vessels. In particular, remodeling of the spiral arteries by EVTs is critical for adapting blood flow and nutrient transport to the developing fetus. Failures in this process have been noticed in different pregnancy complications such as preeclampsia, intrauterine growth restriction, stillbirth, or recurrent abortion. Upon invasion into the decidua, the endometrium of pregnancy, EVTs encounter different maternal cell types such as decidual macrophages, uterine NK (uNK) cells and stromal cells expressing a plethora of growth factors and cytokines. Here, we will summarize development of the EVT lineage, a process occurring independently of the uterine environment, and formation of its different subtypes. Further, we will discuss interactions of EVTs with arteries, veins and lymphatics and illustrate how the decidua and its different immune cells regulate EVT differentiation, invasion and survival. The present literature suggests that the decidual environment and its soluble factors critically modulate EVT function and reproductive success.

XCL1-XCR1 pathway promotes trophoblast invasion at maternal-fetal interface by inducing MMP-2/MMP-9 activity

PROBLEM

Certain chemokines with their receptors can promote or inhibit trophoblast cell migration and invasion in human first-trimester placenta. Whether the lymphotactin (Lptn; XCL1)-XC chemokine receptor 1 (XCR1) chemokine pathway affects trophoblast cell migration and invasion in human first-trimester placenta remains unclear.

METHOD OF STUDY

The expression pattern of chemokine XCL1 and its receptor XCR1 was detected in human first-trimester by qRT-PCR, and the effect of recombinant human XCL1 (rhXCL1) on trophoblast cell function was tested by wound healing and Transwell assays. Matrix metalloproteinase (MMP) activity in trophoblast cells treated with rhXCL1 was assessed via qRT-PCR and gelatin zymography.

RESULTS

Abundant XCR1 mRNA was expressed in the first-trimester decidua and villi. XCL1 and XCR1 mRNA were expressed at a higher level in the first-trimester than in the term placenta. RhXCL1 promoted trophoblast cell migration and invasion by increasing MMP-9 and MMP-2 activity and that of the MMP-2/tissue inhibitor of metalloproteinases 2 (TIMP-2) complex via the phosphatidylinositol 3-kinase (PI3K)/AKT kinase (AKT), mitogen-activated protein kinase (MEK), and JUN N-terminal kinase (JNK) signaling pathways.

CONCLUSION

XCL1-XCR1 chemokine pathway promotes trophoblast invasion by increasing matrix metalloproteinase activity in human first-trimester placenta.

Maternal one carbon metabolism through increased oxidative stress and disturbed angiogenesis can influence placental apoptosis in preeclampsia

Adequate maternal nutrition is critical for a healthy pregnancy outcome and poor maternal nutrition is known to be associated with pregnancy complications like preeclampsia. We have earlier demonstrated that there is an imbalance in the levels of micronutrients (folate and vitamin B₁₂) along with low levels of long chain polyunsaturated fatty acids (LCPUFA) and high homocysteine levels in women with preeclampsia. Homocysteine is known to be involved in the formation of free radicals leading to increased oxidative stress. Higher oxidative stress has been shown to be associated with increased apoptotic markers in the placenta. Preeclampsia is of placental origin and is associated with increased oxidative stress, disturbed angiogenesis and placental apoptosis. The process of angiogenesis is important for placental and fetal development and various angiogenic growth factors inhibit apoptosis by inactivation of proapoptotic proteins through a series of cellular signalling pathways. We propose that an altered one carbon cycle resulting in increased oxidative stress and impaired angiogenesis will contribute to increased placental apoptosis leading to preeclampsia. Understanding the association of one carbon cycle components and the possible mechanisms through which they regulate apoptosis will provide clues for reducing risk of pregnancy complications.

Matrix Metalloproteinases, Vascular Remodeling, and Vascular Disease

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that degrade various proteins in the extracellular matrix (ECM). Typically, MMPs have a propeptide sequence, a catalytic metalloproteinase domain with catalytic zinc, a hinge region or linker peptide, and a hemopexin domain. MMPs are commonly classified on the basis of their substrates and the organization of their structural domains into collagenases, gelatinases, stromelysins, matrilysins, membrane-type (MT)-MMPs, and other MMPs. MMPs are secreted by many cells including fibroblasts, vascular smooth muscle (VSM), and leukocytes. MMPs are regulated at the level of mRNA expression and by activation through removal of the propeptide domain from their latent zymogen form. MMPs are often secreted in an inactive proMMP form, which is cleaved to the active form by various proteinases including other MMPs. MMPs degrade various protein substrates in ECM including collagen and elastin. MMPs could also influence endothelial cell function as well as VSM cell migration, proliferation, Ca²⁺ signaling, and contraction. MMPs play a role in vascular tissue remodeling during various biological processes such as angiogenesis, embryogenesis, morphogenesis, and wound repair. Alterations in specific MMPs could influence arterial remodeling and lead to various pathological disorders such as hypertension, preeclampsia, atherosclerosis, aneurysm formation, as well as excessive venous dilation and lower extremity venous disease. MMPs are often regulated by endogenous tissue inhibitors of metalloproteinases (TIMPs), and the MMP/TIMP ratio often determines the extent of ECM protein degradation and tissue remodeling. MMPs may serve as biomarkers and potential therapeutic targets for certain vascular disorders.

Altered Maternal Serum Matrix Metalloproteinases MMP-2, MMP-3, MMP-9, and MMP-13 in Severe Early- and Late-Onset Preeclampsia

OBJECTIVE

The aim of this study was to determine whether maternal serum matrix metalloproteinases 2, 3, 9, and 13 levels differ in early- and late-onset preeclampsia and uncomplicated pregnancies.

PATIENTS AND METHODS

The study was carried out in 125 pregnant women (29 with early-onset preeclampsia; 31 preeclamptic patients with late-onset preeclampsia; and 65 healthy pregnant controls). Levels of MMP-2, MMP-3, MMP-9, and MMP-13 were measured in the maternal serum using an enzyme-linked immunosorbent assay.

RESULTS

Maternal serum MMP-2 levels in both the groups of preeclamptic women were significantly higher than those in the controls. Levels of MMP-3 were significantly higher in preeclamptic patients with early-onset disease; however, the MMP-3 levels in patients with late-onset preeclampsia were similar to those observed in the control subjects. MMP-9 levels were lower whereas the levels of MMP-13 were higher in both preeclamptic groups of pregnant women than in the healthy controls, but these differences were statistically insignificant.

CONCLUSIONS

One important finding of the present study was that MMP-3 appears to be involved solely in early-onset preeclampsia, but not in late-onset preeclampsia. Higher levels of MMP-2 and MMP-13 and lower levels of MMP-9 seem to be related to both early- and late-onset severe preeclampsia.

Bisphenol A exposure promotes HTR-8/SVneo cell migration and impairs mouse placentation involving upregulation of integrin-β1 and MMP-9 and stimulation of MAPK and PI3K signaling pathways

In this study, we investigated the effect of Bisphenol A (BPA), an endocrine-disrupting chemical, on the migration of human trophoblasts and mouse placentation by using the primary extravillous trophoblast (EVT) and its cell line HTR-8/SVneo, villous explant cultures, and pregnant mice. BPA increased EVT motility and the outgrowth of villous explants in a dose-dependent manner. BPA also increased the protein levels of integrin-β1 and matrix metalloproteinase (MMP)-9 in human EVTs. Low-dose BPA (≤50 mg) increased the protein levels of MMP-9 and MMP-2 as well as integrin-β1 and integrin-α5 in mouse placenta and decreased the proportion of the labyrinth and spongiotrophoblast layers. Inhibitors of mitogen-activated protein kinase (MAPK) U0126 and phosphatidylinositol-3-kinases (PI3K) LY294002 reversed the protein levels of integrin-β1 and MMP-9 as well as the migratory ability induced by BPA. In conclusion, these results indicated that BPA can enhance trophoblast migration and impair placentation in mice by a mechanism involving upregulation of integrin(s) and MMP(s) as well as the stimulation of MAPK and PI3K/Akt (protein kinase B) signaling pathways.

Differentiation of first trimester cytotrophoblast to extravillous trophoblast involves an epithelial-mesenchymal transition

The transformation of cytotrophoblast (CTB) to extravillous trophoblast (EVT) is an essential process for placental implantation. EVT generated at the tips of the anchoring villi migrate away from the placenta and invade the endometrium and maternal spiral arteries, where they modulate maternal immune responses and remodel the arteries into high-volume conduits to facilitate uteroplacental blood flow. The process of EVT differentiation has several factors in common with the epithelial-to-mesenchymal transition (EMT) observed in embryonic development, wound healing and cancer metastasis. We hypothesized that the generation of invasive EVT from CTB was a form of EMT. We isolated paired CTB and EVT from first trimester placentae, and compared their gene expression using a PCR array comprising probes for genes involved in EMT. Out of 84 genes, 24 were down-regulated in EVT compared to CTB, including epithelial markers such as E-cadherin (-11-fold) and occludin (-75-fold). Another 30 genes were up-regulated in EVT compared to CTB including mesenchymal markers such as vimentin (235-fold) and fibronectin (107-fold) as well as the matrix metalloproteinases, MMP2 and MMP9 (357-fold, 129-fold). These alterations also included major increases in the ZEB2 (zinc finger E-box binding homeobox 2, 198-fold) and TCF4 (transcription factor 4, 18-fold) transcription factors, suggesting possible stimulatory mechanisms. There was substantial up-regulation of the genes encoding TGFβ1 and TGFβ2 (48-fold, 115-fold), which may contribute to the maintenance of the mesenchymal-like phenotype. We conclude that transformation of CTB to EVT is consistent with an EMT, although the differences with other types of EMT suggest this may be a unique form.

Role of human cytomegalovirus in the proliferation and invasion of extravillous cytotrophoblasts isolated from early placentae

AIM

We investigated the role of human cytomegalovirus (HCMV) and its mechanism in extravillous cytotrophoblast (EVT) proliferation and invasion in vitro.

METHODS

Differential enzymatic digestion combined with gradient centrifugation, was used to isolate primary EVT from human chorionic villi collected from early placentae of healthy pregnant women. HCMV infection was determined by immunofluorescence staining of HCMVpp65 antigen expression. An MTT assay was used to examine the role of HCMV in the proliferation of EVT. Quantitative real-time polymerase chain reaction (qRT-PCR), immunocytochemical staining and Western blots were carried out in a control group (EVT) and a virus group (EVT+HCMV) to examine the expression of major genes and protein in TGF-β/Smad signaling pathways in EVT 48 h after inoculation with HCMV. An in vitro cell invasion assay was performed to analyze the influence of HCMV on EVT invasion.

RESULTS

HCMV significantly inhibited the proliferation of EVT 48 h after viral infection (P < 0.05). The expression of TGF-β1, Smad1, Smad2, Smad3, Smad4, and Smad5 genes was significantly increased (P < 0.05), but that of TGF-β2, TGF-β3, TGFβRI, TGFβRII, Smad7, MMP2, and MMP9 was significantly decreased in the virus group 48 h after HCMV infection (P < 0.05). Smad7, MMP-2 and MMP-9 protein levels were significantly decreased and the TGF-β1 protein level was significantly increased in infected EVT (all P < 0.05).

CONCLUSIONS

HCMV may act on multiple steps of the TGF-β/Smad signaling pathway to impede EVT proliferation and invasion.

Regional changes of placental vascularization in preeclampsia: a review

Preeclampsia is characterized by vascular dysfunction and results in maternal and fetal morbidity and mortality. The placenta plays a critical role in the growth and development of the fetus, and recent studies indicate that placental architecture, oxygen availability, and oxidative stress indices vary across different regions of the placenta. Our earlier studies have reported altered maternal angiogenesis and differential placental gene expression and methylation patterns of angiogenic factors in women with preeclampsia when compared with normotensive women. We have also demonstrated lower maternal and placental neurotrophin (NT) levels in women with preeclampsia. Studies suggest that oxidative stress is associated with proteases like matrix metalloproteinases (MMPs) and growth factors like NTs and angiogenic factors known to be involved in the process of angiogenesis. Recently, we have reported regionwise differential oxidative stress, antioxidant enzyme activity, and NT levels in placenta from normotensive control women and women with preeclampsia. The current review describes the regional changes in the placenta and highlights the role of placental oxidative stress in influencing regional differences in the expression of angiogenic factors, MMPs, and NTs. This review discusses the need for further research on various growth factors and proteins involved in the process of placental development across different regions of the placenta. This would help to understand whether regional differences in these factors affect the growth and development of the fetus.

Dysregulated expression of matrix metalloproteinases and their inhibitors may participate in the pathogenesis of pre-eclampsia and fetal growth restriction

BACKGROUND

Trophoblast invasion into the maternal endometrium serves an important function in human pregnancy. Dysregulation of the finely controlled process of trophoblast invasion can result in a wide spectrum of pregnancy abnormalities.

AIMS

We aimed to elucidate the relationship between the expression of matrix metalloproteinases and pregnancy complication.

STUDY DESIGN

The study group consisted of placental bed biopsy tissues obtained from normal vaginal deliveries (N=15), normal cesarean deliveries (N=15), pre-eclampsia (N=24) and fetal growth restriction (FGR) (N=10). We evaluated the expressions of MMP-2, -8, -9, -11, -19, -15 (MT2-MMP), -16 (MT3-MMP), and -24 (MT5-MMP), as well as TIMP-1 and -3, by applying Western blot and immunohistochemistry methods.

SUBJECTS

Human placental tissues were used for this study.

OUTCOME MEASURES

The expressions of MMP-2, -8, -9, -11, -19, -15 (MT2-MMP), -16 (MT3-MMP), and -24 (MT5-MMP), as well as TIMP-1 and -3 in human placenta tissues.

RESULTS

Compared with those in normal pregnancies, the expression of MMP-2, -8, -9 and -11 was downregulated in villous tissues of pre-eclampsia and FGR cases (p<0.05). TIMP-1 and -3 were increased in pre-eclampsia and FGR (p<0.05). No significant difference was found between normal vaginal deliveries and cesarean deliveries.

CONCLUSIONS

We speculate that the change in invasion-associated proteinase expression will affect placental development and may thus contribute to the development of complicated pregnancies.

Aberrant placental immune parameters in the feline immunodeficiency virus (FIV)-infected cat suggest virus-induced changes in T cell function

Background

Immune activity during pregnancy must be tightly regulated to ensure successful pregnancy. This regulation includes the suppression of inflammatory activity that could target the semi-allogeneic fetus. Tregs are immunosuppressive; Th17 cells are pro-inflammatory. A precise balance in the two cell populations is critical to pregnancy maintenance, while dysregulation in this balance accompanies compromised pregnancy in humans and mice. FIV is known to target Tregs preferentially in the infected cat. Therefore, it may be hypothesized that FIV infection alters the placental Treg/Th17 cell balance resulting in aberrant immunomodulator expression by these cells and consequent pregnancy perturbation.

Methods

RNA was purified from random sections of whole placental tissues collected from both uninfected and FIV-infected queens at early pregnancy, including tissues from viable and nonviable fetuses. Real time qPCR was performed to quantify expression of intranuclear markers of Tregs (FoxP3) and Th17 cells (RORγ); cytokine products of Tregs (IL-10 and TGF-β), Th17 cells (IL-2, IL-6, and IL-17a), and macrophages (IL-1β); and the FIV gag gene. Pairwise comparisons were made to evaluate coexpression patterns between the cytokines and between the cytokines and the virus.

Results

Both FoxP3 and RORγ were reduced in placentas of infected animals. Neither infection status nor fetal viability affected placental expression of IL-1β. However, fetal nonviability was associated with reduced levels of all other cytokines. Infection and fetal nonviability impacted coexpression of various cytokine pairs. No obvious bias toward Treg or Th17 cells was observed.

Conclusions

FIV infection coupled with fetal nonviability alters expression patterns of T cell cytokines. These data suggest that functionally altered placental T cell leukocyte populations may occur in the infected queen and possibly contribute to fetal nonviability.

The role of interleukin-1β in human trophoblast motility

The pleiotropic cytokine interleukin-1β (IL-1β) can promote physiological cell migration, as well as cancer cell invasion and metastasis. Its role in human trophoblast invasion, however, has not been satisfactorily answered since direct, indirect as well as no effects on trophoblast motility have been published. Therefore, the role of IL-1β has been re-evaluated by exclusively using human primary trophoblast model systems. Immunofluorescence of first trimester placentae indicated IL-1 receptor 1 (IL-1R1) protein expression in first trimester villous cytotrophoblasts (vCTB) and extravillous trophoblasts (EVT). The latter expressed higher mRNA levels of the receptor as shown by comparative gene chip data of vCTB and EVT. Similarly, Western blot analyses and immunofluorescence revealed a time- and differentiation-dependent increase of IL-1R1 in primary EVT seeded on fibronectin. IL-1β dose-dependently elevated migration of isolated first trimester EVT through fibronectin-coated transwells, which was inhibited in the presence of IL-1R antagonist (IL-1Ra), whereas proliferation of these cells was not affected. Similarly, the interleukin did not alter proliferation of vCTB and cell column trophoblasts in floating villi of early pregnancy, but promoted migration in villous explant cultures seeded on collagen I. Western blot analyses of supernatants of primary EVT and first trimester villous explant cultures revealed IL-1β induced secretion of urokinase plasminogen activator (uPA), plasminogen activator inhibitor (PAI)-1 and PAI-2, which was diminished upon combined IL-1β/IL-1Ra treatment. In conclusion, these data suggest that IL-1β directly promotes trophoblast motility of first trimester EVT involving the uPA/PAI system.

Extravillous trophoblast and decidual natural killer cells: a remodelling partnership

BACKGROUND

During pregnancy, maternal uterine spiral arteries (SAs) are remodelled from minimal-flow, high-resistance vessels into larger diameter vessels with low resistance and high flow. Fetal extravillous trophoblasts (EVT) have important roles in this process. Decidual natural killer cells (dNK cells) are the major maternal immune component of the decidua and accumulate around SAs before trophoblast invasion. A role for dNK cells in vessel remodelling is beginning to be elucidated. This review examines the overlapping and dissimilar mechanisms used by EVT and dNK cells in this process and how this may mirror another example of tissue remodelling, namely cancer development.

METHODS

The published literature was searched using Pubmed focusing on EVT, dNK cells and SA remodelling. Additional papers discussing cancer development are also included.

RESULTS

Similarities exist between actions carried out by dNK cells and EVT. Both interact with vascular cells lining the SA, as well as with each other, to promote transformation of the SA. EVT differentiation has previously been likened to the epithelial-mesenchymal transition in cancer cells, and we discuss how dNK-EVT interactions at the maternal-fetal interface can also be compared with the roles of immune cells in cancer.

CONCLUSIONS

The combined role that dNK cells and EVT play in SA remodelling suggests that these interactions could be described as a partnership. The investigation of pregnancy as a multicellular system involving both fetal and maternal components, as well as comparisons to similar examples of tissue remodelling, will further identify the key mechanisms in SA remodelling that are required for a successful pregnancy.

Rotating cell culture systems for human cell culture: human trophoblast cells as a model

The field of human trophoblast research aids in understanding the complex environment established during placentation. Due to the nature of these studies, human in vivo experimentation is impossible. A combination of primary cultures, explant cultures and trophoblast cell lines support our understanding of invasion of the uterine wall and remodeling of uterine spiral arteries by extravillous trophoblast cells (EVTs), which is required for successful establishment of pregnancy. Despite the wealth of knowledge gleaned from such models, it is accepted that in vitro cell culture models using EVT-like cell lines display altered cellular properties when compared to their in vivo counterparts. Cells cultured in the rotating cell culture system (RCCS) display morphological, phenotypic, and functional properties of EVT-like cell lines that more closely mimic differentiating in utero EVTs, with increased expression of genes mediating invasion (e.g. matrix metalloproteinases (MMPs)) and trophoblast differentiation. The Saint Georges Hospital Placental cell Line-4 (SGHPL-4) (kindly donated by Dr. Guy Whitley and Dr. Judith Cartwright) is an EVT-like cell line that was used for testing in the RCCS. The design of the RCCS culture vessel is based on the principle that organs and tissues function in a three-dimensional (3-D) environment. Due to the dynamic culture conditions in the vessel, including conditions of physiologically relevant shear, cells grown in three dimensions form aggregates based on natural cellular affinities and differentiate into organotypic tissue-like assemblies. The maintenance of a fluid orbit provides a low-shear, low-turbulence environment similar to conditions found in vivo. Sedimentation of the cultured cells is countered by adjusting the rotation speed of the RCCS to ensure a constant free-fall of cells. Gas exchange occurs through a permeable hydrophobic membrane located on the back of the bioreactor. Like their parental tissue in vivo, RCCS-grown cells are able to respond to chemical and molecular gradients in three dimensions (i.e. at their apical, basal, and lateral surfaces) because they are cultured on the surface of porous microcarrier beads. When grown as two-dimensional monolayers on impermeable surfaces like plastic, cells are deprived of this important communication at their basal surface. Consequently, the spatial constraints imposed by the environment profoundly affect how cells sense and decode signals from the surrounding microenvironment, thus implying an important role for the 3-D milieu. We have used the RCCS to engineer biologically meaningful 3-D models of various human epithelial tissues. Indeed, many previous reports have demonstrated that cells cultured in the RCCS can assume physiologically relevant phenotypes that have not been possible with other models. In summary, culture in the RCCS represents an easy, reproducible, high-throughput platform that provides large numbers of differentiated cells that are amenable to a variety of experimental manipulations. In the following protocol, using EVTs as an example, we clearly describe the steps required to three-dimensionally culture adherent cells in the RCCS.

Regulation of trophoblast invasion: the role of matrix metalloproteinases

Pregnancy success is determined by a complex progress that includes trophoblast invasion and placentation. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are metal-dependent endopeptidases capable of degrading extracellular matrix, and appear to play a critical role in trophoblast invasion. This article reviews in detail the role of MMPs, TIMPs, and their regulators in the mechanism of trophoblast invasion in early human pregnancy.

Matrix metalloproteinase inhibitors as investigative tools in the pathogenesis and management of vascular disease

Matrix metalloproteinases (MMPs) are proteolytic enzymes that degrade various components of the extracellular matrix (ECM). MMPs could also regulate the activity of several non-ECM bioactive substrates and consequently affect different cellular functions. Members of the MMPs family include collagenases, gelatinases, stromelysins, matrilysins, membrane-type MMPs, and others. Pro-MMPs are cleaved into active MMPs, which in turn act on various substrates in the ECM and on the cell surface. MMPs play an important role in the regulation of numerous physiological processes including vascular remodeling and angiogenesis. MMPs may also be involved in vascular diseases such as hypertension, atherosclerosis, aortic aneurysm, and varicose veins. MMPs also play a role in the hemodynamic and vascular changes associated with pregnancy and preeclampsia. The role of MMPs is commonly assessed by measuring their gene expression, protein amount, and proteolytic activity using gel zymography. Because there are no specific activators of MMPs, MMP inhibitors are often used to investigate the role of MMPs in different physiologic processes and in the pathogenesis of specific diseases. MMP inhibitors include endogenous tissue inhibitors (TIMPs) and pharmacological inhibitors such as zinc chelators, doxycycline, and marimastat. MMP inhibitors have been evaluated as diagnostic and therapeutic tools in cancer, autoimmune disease, and cardiovascular disease. Although several MMP inhibitors have been synthesized and tested both experimentally and clinically, only one MMP inhibitor, i.e., doxycycline, is currently approved by the Food and Drug Administration. This is mainly due to the undesirable side effects of MMP inhibitors especially on the musculoskeletal system. While most experimental and clinical trials of MMP inhibitors have not demonstrated significant benefits, some trials still showed promising results. With the advent of new genetic and pharmacological tools, disease-specific MMP inhibitors with fewer undesirable effects are being developed and could be useful in the management of vascular disease.

Immunomodulator expression in trophoblasts from the feline immunodeficiency virus (FIV)-infected cat

Background

FIV infection frequently compromises pregnancy under experimental conditions and is accompanied by aberrant expression of some placental cytokines. Trophoblasts produce numerous immunomodulators that play a role in placental development and pregnancy maintenance. We hypothesized that FIV infection may cause dysregulation of trophoblast immunomodulator expression, and aberrant expression of these molecules may potentiate inflammation and compromise pregnancy. The purpose of this project was to evaluate the expression of representative pro-(TNF-α, IFN-γ, IL-1β, IL-2, IL-6, IL-12p35, IL-12p40, IL-18, and GM-CSF) and anti-inflammatory cytokines (IL-4, IL-5, and IL-10); CD134, a secondary co-stimulatory molecule expressed on activated T cells (FIV primary receptor); the chemokine receptor CXCR4 (FIV co-receptor); SDF-1α, the chemokine ligand to CXCR4; and FIV gag in trophoblasts from early-and late-term pregnancy.

Methods

We used an anti-cytokeratin antibody in immunohistochemistry to identify trophoblasts selectively, collected these cells using laser capture microdissection, and extracted total RNA from the captured cell populations. Real time, reverse transcription-PCR was used to quantify gene expression.

Results

We detected IL-4, IL-5, IL-6, IL-1β, IL-12p35, IL-12p40, and CXCR4 in trophoblasts from early-and late-term pregnancy. Expression of cytokines increased from early to late pregnancy in normal tissues. A clear, pro-inflammatory microenvironment was not evident in trophoblasts from FIV-infected queens at either stage of pregnancy. Reproductive failure was accompanied by down-regulation of both pro-and anti-inflammatory cytokines. CD134 was not detected in trophoblasts, and FIV gag was detected in only one of ten trophoblast specimens collected from FIV-infected queens.

Conclusion

Feline trophoblasts express an array of pro-and anti-inflammatory immunomodulators whose expression increases from early to late pregnancy in normal tissues. Non-viable pregnancies were associated with decreased expression of immunomodulators which regulate trophoblast invasion in other species. The detection of FIV RNA in trophoblasts was rare, suggesting that the high rate of reproductive failure in FIV-infected queens was not a direct result of viral replication in trophoblasts. The influence of placental immune cells on trophoblast function and pregnancy maintenance in the FIV-infected cat requires additional study.

Cellular and molecular regulation of spiral artery remodelling: lessons from the cardiovascular field

A number of important changes take place in the maternal uterine vasculature during the first few weeks of pregnancy resulting in increased blood flow to the intervillous space. Vascular endothelial and smooth muscle cells are lost from the spiral arteries and are replaced by fetal trophoblast cells. Failure of the vessels to remodel sufficiently is a common feature of pregnancy pathologies such as early pregnancy loss, intrauterine growth restriction and pre-eclampsia. There is evidence to suggest that some vascular changes occur prior to trophoblast invasion, however, in the absence of trophoblasts remodelling of the spiral arteries is reduced. Until recently our knowledge of these events has been obtained from immunohistochemical studies which, although extremely useful, can give little insight into the mechanisms involved. With the development of more complex in vitro models a picture of events at a cellular and molecular level is beginning to emerge, although some caution is required in extrapolating to the in vivo situation. Trophoblasts synthesise and release a plethora of cytokines and growth factors including members of the tumour necrosis factor family. Studies suggest that these factors may be important in regulating the remodelling process by inducing both endothelial and vascular smooth muscle cell apoptosis. In addition, it is evident from studies in other vascular beds that the structure of the vessel is influenced by factors such as flow, changes in the composition of the extracellular matrix, the phenotype of the vascular cells and the local immune cell environment. It is the aim of this review to present our current knowledge of the mechanisms involved in spiral artery remodelling and explore other possible pathways and cellular interactions that may be involved, informed by studies in the cardiovascular field.

In vitro fertilization and embryo culture strongly impact the placental transcriptome in the mouse model

Background

Assisted Reproductive Technologies (ART) are increasingly used in humans; however, their impact is now questioned. At blastocyst stage, the trophectoderm is directly in contact with an artificial medium environment, which can impact placental development. This study was designed to carry out an in-depth analysis of the placental transcriptome after ART in mice.

Methodology/Principal Findings

Blastocysts were transferred either (1) after in vivo fertilization and development (control group) or (2) after in vitro fertilization and embryo culture. Placentas were then analyzed at E10.5. Six percent of transcripts were altered at the two-fold threshold in placentas of manipulated embryos, 2/3 of transcripts being down-regulated. Strikingly, the X-chromosome harbors 11% of altered genes, 2/3 being induced. Imprinted genes were modified similarly to the X. Promoter composition analysis indicates that FOXA transcription factors may be involved in the transcriptional deregulations.

Conclusions

For the first time, our study shows that in vitro fertilization associated with embryo culture strongly modify the placental expression profile, long after embryo manipulations, meaning that the stress of artificial environment is memorized after implantation. Expression of X and imprinted genes is also greatly modulated probably to adapt to adverse conditions. Our results highlight the importance of studying human placentas from ART.