Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Loegl, J.
Paracrine regulation of feto-placental angiogenesis by placental macrophages and trophoblasts
PhD-Studium (Doctor of Philosophy); Humanmedizin; [ Dissertation ] ; 2018. pp. 94
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Desoye Gernot
- Huppertz Berthold
- Lang-Olip Ingrid
- Altmetrics:
- Abstract:
- Within the placenta, the rapidly expanding feto-placental vasculature needs tight control by paracrine and endocrine mechanisms. Here, we focused on paracrine influence by trophoblasts (TB) and tissue macrophages (Hofbauer cells, HBC). First we aimed to characterize the specific polarisation and phenotype of HBC and investigated the role of HBC in feto-placental angiogenesis. Secondly, we intended to identify differences in regulation of feto-placental angiogenesis by early vs late trophoblast. HBC: Placental macrophages were isolated from third trimester placentas and their phenotype was determined by presence of cell surface markers (FACS analysis) and secretion of cytokines (ELISA). HBC conditioned medium (CM) was analysed for pro-angiogenic factors, and the effect of HBC CM on angiogenesis, proliferation and chemoattraction of isolated primary feto-placental endothelial cells (fpEC) was determined in vitro. Our results revealed that isolated HBC possess an M2 polarisation, with M2a, M2b and M2c characteristics. HBC secreted the pro-angiogenic molecules VEGF and FGF2. Furthermore, HBC CM stimulated in vitro angiogenesis of fpEC. However, compared to control medium, chemoattraction of fpEC towards HBC CM was reduced. These findings demonstrate a paracrine regulation of feto-placental angiogenesis by HBC in vitro. TB: The effect of conditioned media (CM) from early and late pregnancy trophoblast was tested on network formation, migration and proliferation of fpEC. Only CM of late pregnancy trophoblast reduced network formation and migration. Screening of trophoblast transcriptome for anti-angiogenic candidates identified pigment epithelium derived factor (PEDF) with higher expression and protein secretion in late pregnancy trophoblast. Addition of a PEDF neutralizing antibody restored the anti-angiogenic effect of CM from late pregnancy trophoblast. Notably, human recombinant PEDF reduced network formation only in combination with VEGF (vascular endothelial growth factor). Analysis of phosphorylation of ERK1/2 (extracellular-signal related kinases) and FAK (focal adhesion kinase), two key players in VEGF-induced proliferation and migration, revealed that PEDF altered VEGF signalling, while PEDF alone did not affect phosphorylation of ERK1/2 and FAK. This data suggest that the trophoblast derived anti-angiogenic molecule PEDF is involved in restricting growth and expansion of the placental endothelium predominantly in late pregnancy, whereas HBC are likely to support placental angiogenesis.