Differentiation of amniotic epithelial cells into various liver cell types and potential therapeutic applications

The aim of Regenerative Medicine is to replace or regenerate human cells, tissues or organs in order to restore normal function. Among all organs, the liver is endowed with remarkable regenerative capacity. Nonetheless, there are conditions in which this ability is impaired, and the use of isolated cells, including stem cells, is being considered as a possible therapeutic tool for the management of chronic hepatic disease.Placenta holds great promise for the field of regenerative medicine. It has long been used for the treatment of skin lesions and in ophthalmology, due to its ability to modulate inflammation and promote healing. More recently, cells isolated from the amniotic membrane are being considered as a possible resource for tissue regeneration, including in the context liver disease. Two cell types can be easily isolated from human amnion: epithelial cells (hAEC) and mesenchymal stromal cells (hAMSC). However only the first cell population has been demonstrated to be a possible source of proficient hepatic cells. This review will summarize current knowledge on the differentiation of hAEC into liver cells and their potential therapeutic application.     

The effect of endothelial cell activation and hypoxia on placental chorionic mesenchymal stem/stromal cell migration

IntroductionChorionic mesenchymal stem/stromal cells (CMSC) can be isolated from the placenta in large numbers. Although their functions are yet to be fully elucidated, they have a role in tissue development and repair. To fulfil such a role, CMSC must be able to migrate to the microenvironment of the injury site. This process is not fully understood and the aim of this study therefore, was to examine in vitro CMSC migration in response to tissue inflammation and hypoxic conditioning.MethodsCMSC were derived from the chorionic villi. A trans-endothelium migration (TEM) assay was used to study CMSC migration through an activated endothelial cell monolayer using the HMEC-1 cell line. A cytokine array was used to identify and compare the cytokine production profile of activated versus non-activated HMEC-1.ResultsThere were significant changes in cytokine production by HMEC-1 cells following lipopolysaccharide (LPS) treatment and hypoxic conditioning. Despite this, results from the TEM assay showed no significant change in the average number of CMSC that migrated through the LPS activated HMEC-1 layer compared to the untreated control. Furthermore, there was no significant change in the average number of CMSC that migrated through the HMEC-1 monolayer when exposed to hypoxic (1% O₂), normoxic (8% O₂) or hyperoxic (21% O₂) conditions.ConclusionThese data suggest that cell functions such as transendothelial migration can vary between MSC derived from different tissues in response to the same biological cues.     

Porphyromonas gingivalis induces IL-8 and IFN-gamma secretion and apoptosis in human extravillous trophoblast derived HTR8/SVneo cells via activation of ERK1/2 and p38 signaling pathways

IntroductionPreterm birth is a major cause for infant mortality and morbidity. A large number of studies have suggested a link between periodontal disease and preterm birth. The purpose of this study was to investigate the interaction between a periodontopathic bacterium Porphyromonas gingivalis and human extravillous trophoblast derived HTR8/SVneo cells.MethodsProduction of cytokines in HTR8 cells was measured via ELISA. Annexin V/PI flow cytometry was performed to assess apoptosis. Protein expression was measured by western blot. Specific pharmacological inhibitors were used to inactivate relevant signaling pathways (p38 MAPK, SB203580; ERK1/2, U0126; JNK, SP600125; NF-κB, JSH-23) to determine their roles in inflammation and apoptosis.ResultsHTR8 cells released significant amounts of IL-8 and IFN-γ during exposure to P. gingivalis. Meanwhile, the percentages of both early and late apoptotic cells increased significantly in response to P. gingivalis. The most significant effect on inflammation was found using SB203580 and U0126, followed by SP600125 and JSH-23. Moreover, U0126 and SB203580 both partially but significantly suppressed P. gingivalis-induced apoptosis, with a large effect by U0126. Additionally, both heat-killed P. gingivalis and P. gingivalis lipopolysaccharide significantly induced IL-8 production.ConclusionP. gingivalis induces inflammation and apoptosis in HTR8 cells, and we demonstrated for the first time that activation of ERK1/2 and p38 MAPK pathways participates in P. gingivalis-induced inflammation and apoptosis. The abnormal regulation of inflammation and apoptosis in human trophoblasts by P. gingivalis infection may give new insights into how maternal periodontal disease and periodontal pathogens might be linked to preterm birth.     

Endometrial androgen signaling and decidualization regulate trophoblast expansion and invasion in co-culture: A time-lapse study

IntroductionTo elucidate whether trophoblast expansion and invasion are modulated by androgen signaling in an in vitro co-culture model system with decidualizing endometrial stromal cells (ESCs).MethodsWe employed an in vitro co-culture model of early embryo implantation, consisting of human ESCs (EtsT499 cells) and spheroids generated by extravillous trophoblast (EVT) derived HTR8/Svneo. The ESCs were decidualized with 8-bromo-cAMP (8-br-cAMP) in the presence or absence of dihydrotestosterone (DHT) at various concentrations for 5 days before co-culture with EVT spheroids. Trophoblast expansion was monitored by fluorescent time-lapse imaging microscopy. ESCs motility was visualized by using CellTracker™ Orange CMRA fluorescent probe. Apoptosis of ESCs was detected by CellEvent™ Caspase-3/7^® green detection reagent. Invasion assays were performed to quantify EVT invasion through a chemotaxis cell membrane.ResultsExpansion of EVT spheroids was significantly enhanced by decidualized compared to undifferentiated ESCs. This process was further stimulated if ESCs were first decidualized in the presence of DHT. In contrast to decidualized ESCs, undifferentiated cells actively migrated away from expanding EVT spheroids. Invasiveness of EVT toward decidualized ESCs was significantly attenuated in comparison to undifferentiated ESCs. DHT had no effect on EVT invasion. However, an inhibitor of intercellular gap junction communication significantly enhanced EVT invasion towards decidualized ESCs.ConclusionsThese results indicate distinct roles for androgen signaling and gap junction formation in decidual cells in regulating trophoblast expansion and invasion.     

Mouse prolyl oligopeptidase plays a role in trophoblast stem cell differentiation into trophoblast giant cell and spongiotrophoblast

IntroductionProlyl oligopeptidase (prolyl endopeptidase, Prep), a multifunctional protease hydrolyzing -Pro-X- peptide bonds, is highly expressed in the mouse placenta, but the function during development is not known. We explored the possibility of Prep's involvement in placental differentiation.MethodsWe cultured trophoblast stem cells (TSCs) derived from the E6.5 mouse embryo and investigated the detailed expression pattern of Prep during their differentiation. Prep-specific inhibitors were added to the TSC culture, and the effect on the differentiation was assessed by microscopic observation and the expression of marker gene for each placental cell.ResultsDuring TSC differentiation for 6 days, Prep was constantly detected at mRNA, protein, and activity levels, and the protein was found mainly in the cytoplasm. The addition of 30 μM and 10 μM SUAM-14746, a Prep-specific inhibitor, effectively inhibited the differentiation into spongiotrophoblasts (SpTs) and trophoblast giant cells (TGCs), while the TSC viability was not affected. 5 μM SUAM-14746 impaired the differentiation into SpTs, and 1 μM SUAM-14746 exhibited no effects. Another Prep-specific inhibitor, KYP-2047, did not affect the differentiation. We confirmed efficient inhibition of Prep enzymatic activity in TSCs by both inhibitors.ConclusionThe dose-dependent effect of SUAM-14746 on TSCs suggests that Prep plays an important role in the differentiation into SpTs and TGCs in the mouse placenta.     

Expression patterns of the chromosome 21 MicroRNA cluster (miR-99a,miR-125b and let-7c) in chorioamniotic membranes

Trisomy 21 (T21) is the most common chromosome abnormality in humans and is associated with a spectrum of phenotypes, including cognitive impairment, congenital heart defects and immune system defects. In addition, T21 is also associated with abnormalities of fetal membranes including chorioamniotic separation, delayed fusion of the chorioamniotic membranes, defects in syncytiotrophoblast formation, as well as amniocyte senescence. There is evidence indicating miRNAs encoded by sequences on chromosome 21 (Chr-21) are involved in several of the cognitive and neurological phenotypes of T21, but the role of Chr-21 derived miRNAs in fetal membrane abnormalities associated with T21 has not been investigated. In the current study, we determined the expression patterns of three miRNAs derived from a cluster on Chr-21 – hsa-miR-99a, hsa-miR-125b and hsa-let-7c in chorioamniotic membranes obtained from term pregnancies with spontaneous rupture (n = 20). Tissue and location specific expression patterns within the chorioamniotic membranes were identified. The rupture zone in the choriodecidua had distinct expression patterns compared to other fetal membrane locations. Despite the increased gene dosage associated with T21, the expression of all three miRNAs was reduced in cultured T21 amniocytes as compared to cultured euploid amniocytes. In silico analysis of experimentally validated targets of the three miRNAs suggest these Chr-21 derived miRNAs play a potential role in fetal membrane rupture and the fetal membrane defects associated with T21.     

Increased placental phospholipase A2 gene expression and free F2-isoprostane levels in response to oxidative stress in preeclampsia

Vasoactive eicosanoids such as thromboxane (TX) A₂ and F₂-isoprostanes (F₂-isoPs) were shown to be increased in the preeclamptic placenta. Only one of the 64 possible isomers of F₂-isoPs derived from the oxidation of arachidonic acid was investigated in the placenta so far. F₂-isoPs are released from membrane phospholipids by phospholipases A₂ (PLA₂) and were shown to act on the TXA₂ receptor (TBXA2R). However, the PLA₂ deregulated in preeclampsia (PE) remains to be determined. In this study, we analyzed the concentrations of six isomers of F₂-isoPs; 8-iso-PGF_2α, 8-iso-15(R)-PGF_2α, 15(R)-PGF_2α, iPF_2α-IV, iPF_2α-VI, 5-iPF_2α-VI and the concentrations of the stable metabolites of TXA₂, TXB_2, by high performance liquid chromatography coupled with tandem mass spectrometry in placentas of PE (n = 17) and normotensive (n = 15) pregnancies according to the biopsy site: peri-insertion or periphery. In the same biopsies, relative mRNA expression of PLA2G2A, PLA2G4A, PLA2G5, PLA2G7, the PLA2 receptor (PLA2R1), the TXA₂ synthase and TBXAR2 were measured by quantitative RT-PCR. We observed similar concentrations of total F₂-isoP isomers between groups whereas higher concentrations (>40%) of free F₂-isoP were observed for all isomers (p ≤ 0.033) in PE than normotensive controls. As expected, we also observed higher placental concentrations of TXB₂ in PE (p = 0.005). Interestingly, we concomitantly found higher mRNA expression of secretory PLA2G2A (p = 0.010), PLA2G5 (p = 0.038) and TBXA2R (p = 0.023) in PE than normotensive placentas. In sum, deregulated PLA₂ could potentially be implicated in freeing F₂-isoP which could participate in local hypertension observed in the PE placenta through the TX pathway.     

Dynamic maternal and fetal Notch activity and expression in placentation

IntroductionMurine placentation requires trophoblast Notch2, while the Notch ligand, JAGGED1, is reduced in invasive trophoblasts from women with preeclampsia. However, the placental cells with active Notch signaling and expression of other Notch proteins and ligands in placentation have yet to be defined. We sought to identify endothelial cell and trophoblast subtypes with canonical Notch signaling in the decidua and placenta and correlate this to expression of Notch proteins and ligands.MethodsNotch reporter transgenic mice were used to define canonical Notch activity and immunofluorescence staining performed to characterize expression of Notch1, 2, 3, 4 and ligands, Delta-like 4 (Dll4) and Jagged1 (Jag1) during early placentation and in the mature placenta.ResultsNotch signaling is active in maternal and fetal endothelial cells and trophoblasts during early placentation and in the mature placenta. Dll4, Jag1, Notch1, and Notch4 are expressed in maternal vasculature in the decidua. Dll4, Jag1 and Notch1 are expressed in fetal vasculature in the labyrinth. Dll4, Notch2 and Notch4 are co-expressed in the ectoplacental cone. Notch2 and Notch4 are expressed in parietal-trophoblast giant cells and junctional zone trophoblasts with active canonical Notch signaling and in labyrinthine syncytiotrophoblasts and sinusoidal-trophoblast giant cells.DiscussionCanonical Notch activity and distinct expression patterns for Notch proteins and ligands was evident in endothelium and trophoblasts, suggesting Notch1, Notch2, Notch4, Dll4, and Jag1 have distinct and overlapping functions in placentation. Characterization of Notch signaling defects in existing mouse models of preeclampsia may shed light on the role of Notch in developing the preeclampsia phenotype.     

Autophagy in the placenta of women with hypertensive disorders in pregnancy

IntroductionAutophagy has not been studied extensively in the human placenta. This study was performed to determine whether autophagy is increased in the placentas of women with hypertensive disorders in pregnancy compared to normotensive pregnancies.MethodsLC3-II and p62 protein expression were examined by quantitative Western blotting analysis in 40 placentas from women not experiencing labor pains. The 40 placentas were from 13, 8, and 19 women with preeclampsia, gestational hypertension, and normal pregnancy, respectively. Hypertensive disorders in pregnancy included preeclampsia and gestational hypertension.ResultsLC3-II expression was significantly increased, while that of p62 was significantly reduced in 21 placentas of women with hypertensive disorders compared to those with normal blood pressure irrespective of the presence or absence of fetal growth restriction (FGR). LC3-II expression was also significantly increased in 13 placentas of women with preeclampsia irrespective of the presence or absence of FGR.DiscussionThe results of this study suggested that autophagy is active in the placenta of hypertensive disorders even in the absence of FGR.     

YAP mediates human decidualization of the uterine endometrial stromal cells

IntroductionThe decidualization of uterine endometrial stromal cells (ESCs) is critical for the successful establishment and maintenance of pregnancy and involves extensive cell proliferation and differentiation. A newly established signaling pathway, the Hippo/Yes-associated protein (YAP) pathway, plays a critical role in these proliferation processes. Our previous study demonstrated that YAP is expressed in human ESCs. However, its role in decidualization remains unclear. The objective of the present study was to explore the role of YAP in the decidualization of human ESCs.MethodsThe expression of YAP was first investigated in the endometrium of non-pregnant women and in the decidua of pregnant women. The role of YAP was investigated by transfecting ESCs with mRNA silencing constructs and observing the negative effects of this action upon decidualization induced in vitro.ResultsOur results revealed that the expression of YAP was higher in decidual cells from early pregnant decidua compared with ESCs from non-pregnant endometrium. The expression levels of YAP and TEA domain 1 (TEAD1) were both increased in ESCs during in vitro decidualization and the knockdown of YAP in ESCs caused negative effects upon decidualization in vitro.DiscussionOur study suggests that YAP is upregulated in human decidual cells compared with ESCs and influences the decidualization of ESCs.     

MiR-136 contributes to pre-eclampsia through its effects on apoptosis and angiogenesis of mesenchymal stem cells

IntroductionMesenchymal stem cells (MSCs) play an important role in the pathology of preeclampsia (PE). The survival of MSCs and angiogenesis in the maternal-fetal interface are important for a successful pregnancy. MicroRNA-136 (miR-136) is highly expressed in decidua-derived MSCs (MSCs) from PE compared with healthy donors (NC). The role of the MSCs aberrant expressed miR-136 in PE development is still unclear. In the present study, we examined the impact of miR-136 on the survival of MSCs and angiogenesis in the maternal-fetal interface.MethodsMSCs were extracted and transfected with miR-136 mimic and interfering RNAs using lipofectamine-2000. Then cell apoptosis were tested using flow cytometry. HUVEC tube formation ability was tested on Matrigel co-cultured with conditioned MSCs supernatants.ResultsHigh level of miR-136 could suppress cell proliferation and promote apoptosis of MSCs through targeting BCL2. It could also impairs HUVEC capillary formation by suppressing VEGF.DiscussionMiR-136 significantly increase the apoptosis and suppress the proliferation of MSCs. It could also inhibit the capillary formation and trophoblast cell invasion. These data suggest that decidua-derived miR-136 that is increased in PE is a potential causal factor of PE.     

Placental concentrations of bisphenol A and birth weight from births in the Southeastern U.S.

IntroductionBisphenol A (BPA) is a weakly estrogenic compound that has been detected in a wide variety of food products and biological matrices (saliva, blood, urine, etc). Despite the potential risk of human exposure to BPA, little information exists concerning maternal and fetal exposure to BPA during pregnancy. The aim of this study is to evaluate the correlation between placental BPA concentration, infant birth weight and calculated birth weight centile, and several other maternal and infant parameters.MethodsPlacental sample were collected from 200 subjects. BPA levels were measured by isotope dilution GC–MS. Additional maternal and infant data were gathered from medical charts and were potential correlates with placental BPA levels.ResultsPlacental BPA concentrations ranged from 4.4 ng/g to 273.9 ng/g in oven-dried tissue (average 103.4 ± 61.8 ng/g). There was a significant negative correlation between calculated birth weight centile and levels of placental BPA (p < 0.05). Low birth weight and small for gestational age infants also had significantly greater placental BPA concentrations as compared to normal weight infants and average/large for gestational age infants. Infants born to African American mothers also had greater placental BPA concentrations as compared to infants born to Hispanic mothers.DiscussionPlacental BPA concentrations are correlated with the growth potential of the fetus and may play a role in reduced fetal growth.     

Maternal obesity induced by a ‘cafeteria’ diet in the rat does not increase inflammation in maternal,placental or fetal tissues in late gestation

IntroductionObesity during pregnancy can cause serious complications for maternal and infant health. While this has often been attributed to increased inflammation during obese pregnancy, human and animal studies exhibit variable results with respect to the inflammatory status of the mother, placenta and fetus. Cafeteria (CAF) feeding induces more inflammation than standard high-fat feeding in non-pregnant animal models. This study investigated whether maternal obesity induced by a CAF diet increases maternal, fetal or placental inflammation.MethodsMaternal obesity was established in rats by 8 weeks of pre-pregnancy CAF feeding. Maternal plasma inflammatory markers (IL-1β, IL-6, IL-10, IL-12p40, MCP1, GRO/KC, MIP-2 and TNFα) and expression of inflammatory genes (Tnfα, Il-6, Il-1β, Tlr2, Tlr4, Cox2 and Emr1) in maternal, placental and fetal tissues were measured at day 21 of gestation.ResultsDespite CAF animals having 63% more central body fat than controls at day 21 of gestation, plasma inflammatory markers were not increased; indeed, levels of IL-6, IL-12p40 and MIP2 were reduced slightly. Similarly, inflammatory gene expression remained largely unaffected by CAF feeding, except for slight reductions to Tlr4 and Emr1 expression in CAF maternal adipose tissue, and reduced Tlr4 expression in male labyrinth zone (LZ). The junctional zone (JZ) displayed increased Il-6 expression in CAF animals when fetal sexes were combined, but no inflammatory genes were affected by the CAF diet in fetal liver.ConclusionsMaternal obesity induced by a CAF diet before and during pregnancy does not increase the inflammatory status of the mother, placenta or fetus in late gestation.     

The effect of yoga training on enhancement of Adrenocorticotropic hormone (ACTH) and cortisol levels in female patients with multiple sclerosis

The effect of 8 weeks yoga training on cortisol and Adrenocorticotropic hormone (ACTH) levels in female patients with Multiple Sclerosis (MS) is examined. Twenty four MS female patients with Expanded Disability Status Scale (EDSS) 1 to 5.5 participated in this study as the subject. The participants were divided into control (n = 10) or training group (n = 14) randomly. Training group performed 90 min yoga training per session, 3 days a week for 8 weeks. Assessments include body composition measurement and blood sampling 48 h before first session and 48 h after the intervention. The results demonstrated that ACTH increased and cortisol decreased compared to the control group (P < 0.05); In conclusion, it seems that yoga training modulates ACTH level in concomitant with reduction in cortisol level in female patients with MS.     

Transendothelial migration of human umbilical mesenchymal stem cells across uterine endothelial monolayers: Junctional dynamics and putative mechanisms

IntroductionDuring pregnancy, fetal stem cells can transfer to the maternal circulation and participate in tissue repair. How they transmigrate across maternal endothelial barriers and whether they can subsequently influence maternal endothelial integrity is not known.MethodsMesenchymal stem cells (WJ-MSC) were isolated from Wharton's jelly and their interactions with human uterine microvascular endothelial cell (HUtMEC) monolayers, junctional occupancy and expression/phosphorylation of vascular endothelial (VE)- cadherin and vascular endothelial growth factor (VEGF-A) secretion was studied over 48h by real time, confocal microscopy, immunoblotting and ELISA.ResultsWJ-MSC displayed exploratory behaviour with interrogation of paracellular openings and spreading into the resultant increased gaps followed by closing of the endothelium over the WJ-MSC. 62% of added cells crossed within 22h to sub-endothelial niches. There was a concomitant loss of junctional VE-cadherin in HUtMEC followed by a full return and increased VE-cadherin expression after 22h. During early hours, VE-cadherin showed a transient phosphorylation at Tyrosine (Tyr)-685 when VEGF-A secretion were high. From 16 to 22h, there was increased de-phosphorylation of Tyr-731. Anti-VEGF-A blocked Tyr-685 phosphorylation but not the decrease in P-Tyr731; this partially inhibited WJ-MSC transmigration.DiscussionFetal WJ-MSC can traverse uterine endothelial monolayers by mediating a non-destructive paracellular pathway. They can promote junctional stability of uterine endothelium from the sub-endothelial niche. Mechanistically, WJ-MSC induces VEGF-dependent phosphorylation events linked with paracellular permeability and VEGF-independent de-phosphorylation events associated with leukocyte extravasation. Our data also allows consideration of a possible role of fetal MSC in mature functioning of the uterine vasculature needed for optimal utero-placental perfusion.