Tumor Necrosis Factor-α Inhibits Trophoblast Migration through Elevation of Plasminogen Activator Inhibitor-1 in First-Trimester Villous Explant Cultures

Abstract

We have tested the hypothesis that elevated concentrations of TNF alpha could impair trophoblast invasion. Using first-trimester placental explant cultures, we have demonstrated that the cytokine inhibits in vitro migration of extravillous trophoblasts (EVT) on collagen I, and invasion through Matrigel. To elucidate the underlying mechanism, proliferation and differentiation of EVT in vitro were analyzed by immunohistochemistry of serial sections, Western blotting, zymography, ELISA, and RT-PCR from RNA pools of mechanically separated cell populations. At 24 h of cultivation in the presence or absence of TNF alpha, anchorage and proliferation of trophoblasts had occurred to generate cell columns containing viable, post-mitotic, differentiated EVT [positive for integrins alpha 1 and alpha 5, matrix metalloproteinase (MMP)-2, and human leukocyte antigen-G1; negative for proliferating cellular nuclear antigen, cytokeratin 18 neoepitope, and in 5-Bromo-2-deoxy-uridine labeling]. At 72 h, control cells had broken away from the column to migrate through the extracellular matrix; whereas, in contrast, TNF alpha-treated EVT remained as contiguous cell columns, despite increased MMP-9 expression. Thus, in vitro MMP9 activity appears not to be essential for trophoblast migration. Expression of plasminogen activator inhibitor (PAI)-1 was elevated in TNF alpha-treated EVT, and adding antibodies that inhibit PAI-1 activity restored migration, whereas tissue-inhibitor-of-metalloproteinases-1-blocking antibodies were ineffective. Induction of PAI-1 by TNF alpha could be related to restricted trophoblast invasion in preeclampsia.

TNF-α alters the inflammatory secretion profile of human first trimester placenta

“…[45][46][47] In the present study, TNF-α at concentrations of 1 and 10 ng/ml were used, which are in fact higher than observed in vivo levels. However, used concentrations are in line with a number of other placental explant studies 9,10,48 and may reflect microenvironmental concentrations in the intervillous space, where autocrine/paracrine acting TNF-α concentrations may be higher than systemic levels.…”

“…7,8 Elevated TNF-α levels during distressed pregnancies have been suggested to affect trophoblast biology including migratory activity, syncytialization, and endocrine function. 9,10 Moreover, elevated TNF-α may influence the fetal-maternal cross-talk by provoking a shift in the secretory profile of placenta-derived immunemodulating factors, which in turn influences the activity of maternal immune cells. Indeed, trophoblast-derived factors can induce differentiation of peripheral blood monocytes into macrophages 11 and enhance recruitment and differentiation of inducible regulatory T cells (Tregs).…”

Notch1 controls development of the extravillous trophoblast lineage in the human placenta

“…Villous explant cultures were performed as described elsewhere (71). In detail, pieces of villous tissues (5-6 mm) were dissected from the placental basal plate (7th-8th wk of gestation), and further divided into two equal parts.…”

Complex Expression Pattern of Wnt Ligands and Frizzled Receptors in Human Placenta and its Trophoblast Subtypes

“…Fibroblasts were characterised by vimentin immunocytochemistry (100% of cells), a contamination with trophoblasts was excluded by cytokeratin 7 staining. Villous explants of first trimester placentae (n = 3) were seeded on Matrigel and after 72 h invaded trophoblasts were separated from attached villi as previously mentioned [17]. JEG-3 choriocarcinoma cells were cultivated in DMEM + 10% FCS.…”