Translational studies have explored the therapeutic effects of stem cells, raising hopes for the treatment of numerous diseases. Here, we evaluated the therapeutic effect of chorionic plate-derived mesenchymal stem cells (CP-MSCs) isolated from human placenta and transplanted into rats with carbon tetrachloride (CCl(4))-injured livers. CP-MSCs were analyzed for hepatocyte-specific gene expression, indocyanine green (ICG) uptake, glycogen storage, and urea production following hepatogenic differentiation. PKH26-labeled CP-MSCs were directly transplanted into the livers of rats that had been exposed to CCl(4) (1.6 g/kg, twice per week for 9 weeks). Blood and liver tissue were analyzed at 1, 2, and 3 weeks post-transplantation. The expression of type I collagen (Col I) and matrix metalloproteinases (MMPs) was analyzed in rat T-HSC/Cl-6 hepatic stellate cells co-cultured with CP-MSCs following exposure to TGF-β. The expression levels of α-smooth muscle actin (α-SMA) and Col I were lower in transplanted (TP) rats than in non-transplanted (Non-TP) animals (P < 0.05), whereas the expression levels of albumin and MMP-9 were increased. TP rats exhibited significantly higher uptake/excretion of ICG than non-TP rats (P < 0.005). In addition, collagen synthesis in T-HSC/Cl-6 cells exposed to TGF-β was decreased by co-culture with CP-MSCs, which triggered the activation of MMP-2 and MMP-9. These results contribute to our understanding of the potential pathophysiological roles of CP-MSCs, including anti-fibrotic effects in liver disease, and provide a foundation for the development of new cell therapy-based strategies for the treatment of difficult-to-treat liver diseases.

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Implantation of the blastocyst into the maternal endometrium is mediated by a population of well-differentiated primary cells of the placenta known as trophoblasts, which grow in an invasive and destructive fashion similar to tumor cells. Interactions between the endometrium and trophoblasts are regulated by a coordinated interplay of extracellular matrix (ECM) proteins secreted by the invading extravillous trophoblasts. Integrins act as adhesion receptors and mediate both cell-ECM and cell-cell interactions. However, the correlation between integrin expression and trophoblast invasion under hypoxia is unclear. Here, we analyzed the expression of integrins in HTR-8/SVneo trophoblast cells exposed to hypoxic conditions in order to demonstrate an association between invasion activity and integrin expression in trophoblasts. Trophoblasts were examined by microarray analysis, RT-PCR, western blotting, and zymography after 1% hypoxic treatment, and cell invasion was estimated. The dynamic expression of integrins and human matrix metalloproteinases (MMPs) was observed under hypoxic conditions. The invasiveness of trophoblasts cultured under 1% hypoxic conditions was significantly greater than that of trophoblasts cultured under normoxic conditions through alterations in MMP-2 and -9 (P < 0.05). Notably, integrin α4 expression during early hypoxia was negatively regulated by hypoxia-inducible factor-1alpha (HIF-1alpha) expression in trophoblasts. The downregulation of integrin α4 expression by siRNA treatment controlled trophoblast invasion activity (P < 0.05). Taken together, we suggest that dynamic changes in integrins, including those in integrin α4 expression by hypoxia, play a regulatory role in trophoblast invasion. These findings expand our understanding of the potential roles of integrin α4 in implantation.

Mesenchymal stem cells (MSCs) have unique immunologic properties that may someday prove useful in cell-based therapy for various degenerative diseases. Its potential is limited, however, by several factors, including the rarity of these cells and difficulty in isolating them. To evaluate their potential as new sources for cell therapy, we isolated MSCs from human fetal tissue (hfMSC) derived from spontaneous abortus (8∼10 weeks) then studied their cell cycle and cell surface marker expression using a fluorescence-activated cell sorter (FACS), as well as the expression of differentiation markers using real-time polymerase chain reaction (RT-PCR). The hfMSCs were able to undergo PCR up to 20 times without displaying significant changes in morphology or expression of various stemness markers (Nanog and human telomerase reverse transcriptase [hAFP]), including germ layer markers (hNF68, alpha-cardiac actin, and hAFP). Also, teratomas were not seen in mice with severe combined immunodeficiency syndrome (SCID) that received a transplantation of hfMSCs with hTERT activity. The FACS analysis revealed that the majority of hfMSCs express mesenchymal markers CD13, CD44, CD71, CD90, CD105, CD253a, and HLA-ABC, but did not express CD31, CD34, CD38, CD45, and HLA-DR. Interestingly, hfMSCs derived from the cell membrane during early passages were negative for both HLA-ABC and HLA-DR, although HLA-ABC expression was detected during later passages (＞20 passages). We found that hfMSCs could be differentiated into an osteogenic lineage; this was indicated by modulation of osteoblast markers specific for mRNA. We conclude that hfMSCs could be used as a new source of cells to treat patients with osteogenic diseases, as well as to understand the mechanisms of immunosuppression by MSCs.

ObjectiveWe investigated the norepinephrine transporter (NET) expression in normal and pre-eclamptic placentas and analyzed the invasion activity of trophoblastic cells based on norepinephrine (NE)-NET regulation.MethodsNET and NE expression levels were examined by western blot and enzyme-linked immunosorbent assay, respectively. Trophoblast invasion activity, depending on NE-NET regulation, was determined by NET-small interfering RNA (siRNA) and NET transfection into the human extravillous trophoblast cells with or without NE treatment and invasion rates were analyzed by zymography and an invasion assay.ResultsNET mRNA was expressed at a low level in pre-eclamptic placentas compared with normal placentas and NE concentration in maternal plasma increased significantly in pre-eclamptic women compared to normal pregnant women (p<0.05). NET gene upregulation and NE treatment stimulated trophoblast cell invasion up to 2.5-fold (p<0.05) by stimulating matrix metalloproteinase-9 activity via the phosphoinositol-3-kinase/AKT signaling pathway, whereas NET-siRNA with NE treatment reduced invasion rates.ConclusionNET expression is reduced by inadequate regulation of NE levels during placental development. This suggests that a complementary balance between NET and NE regulates trophoblast cell invasion activities during placental development.