Human placenta-derived multipotent mesenchymal stromal cells involved in placental angiogenesis via the PDGF-BB and STAT3 pathways.

We studied the smooth muscle cell differentiation capability of human placental multipotent mesenchymal stromal cells (hPMSCs) and identified how endothelial cells recruit hPMSCs participating in vessel formation. hPMSCs from term placentas were induced to differentiate into smooth muscle cells under induction conditions and different matrix substrates. We assessed endothelial cells from umbilical veins for platelet-derived growth factor (PDGF)-BB expression and to induce hPMSC PDGFR-beta and STAT3 activation. Endothelial cells were co-cultured with hPMSCs for in vitro angiogenesis. Cell differentiation ability was then further assessed by mouse placenta transplantation assay. hPMSCs can differentiate into smooth muscle cells; collagen type I and IV or laminin support this differentiation. Endothelial cells expressed significant levels of PDGF-BB and activated STAT3 transcriptional activity in hPMSCs. Endothelial cell-conditioned medium induced hPMSC migration, which was inhibited by STAT3 small interfering RNA transfection or by pretreatement with PDGFR-beta-blocking antibody but not by PDGFR-alpha-blocking antibody or isotype immunoglobulin G (IgG; P < 0.001). hPMSCs can incorporate into endothelial cells with tube formation and promote endothelial cells, forming capillary-like networks than endothelial cells alone (tube lengths: 12 024.1 ± 960.1 vs. 9404.2 ± 584.7 pixels; P < 0.001). Capillary-like networks were significantly reduced by hPMSCs pretreated with PDGFR-beta-blocking antibody but not by PDGFR-alpha-blocking antibody or isotype IgG (P < 0.001). Transplantation of hPMSCs into mouse placentas revealed incorporation of the hPMSCs into vessel walls, which expressed alpha-smooth muscle actin, calponin, and smooth muscle myosin (heavy chain) in vivo. In conclusion, endothelial cell-hPMSC interactions occur during vessel development of placenta. Placental endothelial cell-derived PDGF-BB recruits hPMSCs involved in vascular development via PDGFR-beta/STAT3 activation.

Chen CY ，Liu SH ，Chen CY ，Chen PC ，Chen CP ... -  《-》

Human placental multipotent mesenchymal stromal cells modulate placenta angiogenesis through Slit2-Robo signaling.

Chen CY ，Tsai CH ，Chen CY ，Wu YH ，Chen CP ... -  《-》

The effect of conditioned medium derived from human placental multipotent mesenchymal stromal cells on neutrophils: possible implications for placental infection.

The role of human placental multipotent mesenchymal stromal cells (hPMSCs) in placental inflammation is unknown. We hypothesize that hPMSCs are involved in the early phases of placental infection. hPMSCs were isolated from term placentas and neutrophils from peripheral blood. The expression of toll-like receptors (TLRs) and cytokines by hPMSCs was determined by RT-PCR, flow cytometry and enzyme-linked immunosorbent assay. The effect of conditioned medium of hPMSCs with or without lipopolysaccharide (LPS) pretreatment on neutrophil functions: migration, apoptosis and production of reactive oxygen species (ROS) was assessed by flow cytometry and western blot. hPMSCs expressed TLR1, TLR3, TLR4, TLR6, TLR7 and TLR9. LPS stimulation increased the expression of TLR4 and the production of IL-6 and IL-8 by hPMSCs. Neutrophils exhibited chemotaxis to hPMSC-conditioned medium, which was inhibited by IL-8 depletion. Neutrophil CD11b activation was promoted by hPMSC-conditioned medium, which was further enhanced in media from hPMSCs pretreated with LPS. hPMSC-conditioned medium reduced neutrophil ROS production. Neutrophil phagocytosis was increased by LPS alone but not by hPMSC-conditioned medium with or without LPS stimulation. hPMSC-conditioned medium induced STAT3 activation in neutrophils, which was inhibited by neutralizing antibody to IL-6. hPMSC-conditioned medium rescued neutrophils from apoptosis, but this effect was significantly reduced in conditioned medium of hPMSCs with LPS pretreatment. Depletion of IL-6 from the conditioned medium further inhibited the anti-apoptotic effect on neutrophils. Our results demonstrate that hPMSCs can interact with peripheral blood neutrophils in response to inflammatory signals of the placenta. Cytokines produced by hPMSCs can induce neutrophil chemotaxis and reduce neutrophil apoptosis.

Chen CP ，Chen YY ，Huang JP ，Wu YH ... -  《-》

Paracrine factors from human placental multipotent mesenchymal stromal cells protect endothelium from oxidative injury via STAT3 and manganese superoxide dismutase activation.

Liu SH ，Huang JP ，Lee RK ，Huang MC ，Wu YH ，Chen CY ，Chen CP ... -  《-》

Human placental multipotent mesenchymal stromal cells modulate trophoblast migration via Rap1 activation.

Little is known about the interaction between human placental multipotent mesenchymal stromal cell (hPMSC) and trophoblast. We hypothesize that hPMSCs produce hepatocyte growth factor (HGF) which may interact with trophoblasts and regulate their migration during placentation. hPMSCs were isolated from term placentas and conditioned medium was collected after 2 days of culture in hypoxic (<1% O2) or control (20% O2) conditions. Selective agonist and inhibitor or siRNA for protein kinase A (PKA) or Rap1 were combined with Rap1-GTP pull down assays, flow cytometry, integrin β1 activation assays and adhesion and migration studies to investigate HGF signaling effects in trophoblasts. The hPMSC abundance and HGF level in preeclamptic placentas were compared with gestational age-matched controls. HGF was expressed by hPMSCs and was decreased in hypoxia. HGF induced cAMP production and Rap1 activation in trophoblasts, which in turn activated integrin β1. The HGF and PKA activator 6-Bnz-cAMP induced Rap1 activation with increased trophoblast adhesion and migration. The alterations were inhibited by PKA inhibitor H89 or Rap1 siRNA. HGF and cAMP expression were reduced in preeclamptic placentas. hPMSC number was decreased in preeclamptic placenta compared to controls (0.68 ± 0.1% vs. 1.32 ± 0.5%; P = 0.026). hPMSC conditioned medium enhanced trophoblast migration which was inhibited by c-Met blocking antibody, but migration was reduced by conditioned medium from hPMSC cultured in hypoxia. hPMSCs secrete HGF and increase trophoblast cAMP production. The cAMP effector PKA modulates adhesion and migration of trophoblast via signaling to Rap1 and integrin β1.

Chen CP ，Huang JP ，Chu TY ，Aplin JD ，Chen CY ，Wu YH ... -  《-》