Fig. 2.

Trophoblast differentiation is not significantly affected by platelet-derived factors. Expression of transcription factor GCM1 mRNA (a) and protein levels (b, c) as well as expression of differentiation marker ALPPL2 mRNA (d) and protein levels (e, f) were analyzed in BeWo cells after forskolin induction (20 μM) in the presence and absence of pHPL after 3 h (GCM1) and 48 h (ALPPL2). Additionally, expression of markers for trophoblast differentiation and fusion, syncytin-1 (g, ERVW-1), syncytin-2 (h, ERVFRD-1), and E-cadherin (i, CDH1) were analyzed after 48 h. Scanning electron microscopy analyses showed membrane ruffling in vehicle control BeWo cells (DMSO, 0.1% v/v) incubated without (j) or with (k) pHPL for 48 h. Forskolin-stimulated BeWo cells showed extensive formation of microvilli in absence (l) and presence of pHPL (m). Data in bar graphs are presented as means ± SEM from six (a), four (c), or three (all others) independent experiments using different cell passages. Differences between groups were identified using one-way analysis of variance and Tukey’s multiple comparisons test (a, d, g–i). Western blots are representative for four (b) and three (e) different experiments. For band densitometry (c, f), controls were set to one and data were tested using one sample t test. Scanning electron microscopy images are representative for three different experiments. Scale bar in j represents 10 μm. *p ≤ 0.05, **p ≤ 0.01, ***p < 0.001