Endothelin-1 down-regulates matrix metalloproteinase 14 and 15 expression in human first trimester trophoblasts via endothelin receptor type B

$\textbf{STUDY QUESTION}$: Does endothelin-1 (ET-1) regulate matrix metalloproteinase (MMP) 14 and 15 production and invasion of human first trimester trophoblasts? $\textbf{SUMMARY ANSWER}$: ET-1 in pathophysiological concentrations down-regulates MMP14 and MMP15 expression via endothelin receptor (ETR) type B and decreases trophoblast migration and invasion. $\textbf{WHAT IS KNOWN ALREADY}$: MMP14 and MMP15 are involved in trophoblast invasion. Impairment of invasion has been linked to pregnancy complications such as pre-eclampsia (PE). ET-1 is up-regulated in PE. $\textbf{STUDY DESIGN, SIZE, DURATION}$: $\textit{In vitro}$ study using primary human trophoblasts from 50 first trimester placentas (gestational week 7-12). $\textbf{PARTICIPANTS/MATERIALS, SETTING, METHODS}$: Trophoblasts were cultured in the absence or presence of 10-100 nM ET-1. MMP14 and MMP15 mRNA and protein were quantified by RT-qPCR and Western blotting, respectively. Selective antagonists for ETRA (BQ-123) or ETRB (BQ-788) were used to identify ETR subtypes involved. Functional ET-1 effects were tested in first trimester chorionic villous explants and transwell invasion assays. The roles of tumor necrosis factor (TNF)-α (25 ng/ml) and oxygen (1%) in ET-1 regulation of MMP14 and 15 expression were assessed by Western blotting. $\textbf{MAIN RESULTS AND THE ROLE OF CHANCE}$: ET-1 down-regulated MMP14 and MMP15 mRNA (-21% and -26%, respectively, $\textit{P}$ < 0.05) and protein levels (-18% and -22%, respectively, $\textit{P}$ < 0.05). This effect was mediated via ETRB. ET-1 decreased trophoblast outgrowth in placental explants (-24%, $\textit{P}$ < 0.05) and trophoblast invasion (-26%, $\textit{P}$ ≤ 0.01). TNF-α enhanced ET-1 mediated MMP15 down-regulation (by 10%, $\textit{P}$ < 0.05), whereas hypoxia abolished the effect of ET-1 on both MMPs. $\textbf{LARGE SCALE DATA}$: N/A. $\textbf{LIMITATIONS, REASONS FOR CAUTION}$: Only primary trophoblasts were used in this study. Since trophoblast yield from first trimester placental material is limited, further aspects of MMP14 and 15 regulation could not be characterized. Other anti-invasive factors may be altered by ET-1 in trophoblasts and, thus, contribute to the reduced invasion, but have not been investigated. Oxygen levels similar to those found in the decidua (5-8% O2) were not analyzed in this study. $\textbf{WIDER IMPLICATIONS OF THE FINDINGS}$: ET-1 modifies placental function already during the first trimester of pregnancy, the time-window when the placental changes implicated in PE occur. Thus, our results improve the understanding of the placental mechanisms underlying trophoblast invasion and PE.The study was funded by the Oesterreichische Nationalbank (Anniversary Fund, project number: 14796) and the Herzfelder'sche Familienstiftung (to J.P.; number: 00685). AMM received funding from the Austrian Science Fund FWF (W1241) and the Medical University Graz through the PhD Program Molecular Fundamentals of Inflammation (DK-MOLIN)

Membrane-type matrix metalloproteinase 1 regulates trophoblast functions and is reduced in fetal growth restriction

Fetal growth restriction (FGR) results from placental insufficiency to adequately supply the fetus. This insufficiency involves impaired cytotrophoblast functions, including reduced migration and invasion, proliferation, and syncytium formation. Membrane-type matrix metalloproteinase 1 (MT1-MMP) is a key enzyme in these cellular processes. MT1-MMP exists in various forms: a 63-kDa proenzyme is synthesized as primary translation product, which is cleaved into a 57-kDa membrane-anchored active form. We hypothesized that reduced placental MT1-MMP in FGR impairs trophoblast functions. MT1-MMP mRNA and active enzyme was quantified in placentas from FGR and age-matched control pregnancies. MT1-MMP protein was localized in first-trimester and term placentas. Putative MT1-MMP functions in trophoblasts were determined using two blocking antibodies for measuring migration and proliferation, as well as fusion of primary trophoblasts and trophoblast-derived cells. MT1-MMP was expressed predominantly in the syncytiotrophoblast and the villous and extravillous cytotrophoblasts. In FGR placentas, levels of MT1-MMP mRNA and of active MT1-MMP protein were reduced (-34.2%, P < 0.05, and -21.5%, P < 0.01, respectively), compared with age-matched controls. MT1-MMP-blocking antibodies diminished migration, proliferation, and trophoblast fusion. We conclude that reduced placental MT1-MMP in FGR may contribute to the impaired trophoblast functions associated with this pathology. Copyright \ua9 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved

Placental fractalkine is up-regulated in severe early-onset preeclampsia

The pathogenesis of preeclampsia (PE) includes the release of placental factors into the maternal circulation, inducing an inflammatory environment in the mother. One of the factors may be the proinflammatory chemokine fractalkine, which is expressed in the syncytiotrophoblast of human placenta, from where it is released into the maternal circulation by constitutive shedding. We examined whether placental fractalkine is up-regulated in severe early-onset PE and whether the proinflammatory cytokines tumor necrosis factor (TNF)-{alpha} and IL-6 are able to increase the expression of fractalkine. Gene expression analysis, enzyme-linked immunosorbent assay, and immunohistochemistry consistently showed increased fractalkine expression in placentas from severe early-onset PE, compared to gestational age-matched controls. Expression of a disintegrin and metalloproteinases 10 and 17, which convert transmembrane fractalkine into the soluble form, was significantly increased in these cases. Incubation of first-trimester placental explants with TNF-{alpha} provoked a significant increase in fractalkine expression and release of the soluble form, whereas IL-6 had no effect. TNF-{alpha}-mediated up-regulation of placental fractalkine was reversed in the presence of the aspirin-derivative salicylate, which impaired activation of NF-{kappa}B p65 in TNF-{alpha}-treated explants. On the basis of data from placental explants, we suggest that increased maternal TNF-{alpha} may up-regulate the expression and release of placental fractalkine, which, in turn, may contribute to an exaggerated systemic inflammatory response in PE