Hepatocyte growth factor promotes the growth of cytotrophoblasts by the paracrine mechanism

Human placental extract ameliorates methotrexate-induced hepatotoxicity in rats via regulating antioxidative and anti-inflammatory responses

Purpose

Methotrexate (MTX) induces hepatotoxicity, limiting its clinical efficacy as a widely known chemotherapy drug. In the current study, we examined the protective effect of human placenta extract (HPE) against MTX-induced liver damage in rats, as well as its ability to regulate antioxidative and anti-inflammatory liver responses.

Methods

Male rats were orally administered MTX at a daily dose of 5 mg/kg-body-weight in the presence or absence of HPE (10.08 mg/kg) for 2 weeks. We measured the biological effects of MTX and HPE on the levels of liver enzymes, lipid profile, lipid peroxidation, oxidative stress biomarkers, and cytokines [tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and interleukin-10 (IL-10)]. In addition, histological examination and histopathological scoring of liver tissues were performed.

Results

MTX-treated rats showed significantly increased (p < 0.001) liver enzyme levels for aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin, total cholesterol, and triglyceride levels. However, HPE supplementation in MTX-treated rats significantly decreased (p < 0.001) these elevated levels. HPE supplementation also significantly reduced the oxidative stress biomarker malondialdehyde (MDA), reversed the reduction in glutathione (GSH), and markedly increased the antioxidant enzyme activities of catalase (CAT) and superoxide dismutase (SOD) in the livers of MTX-treated rats. Furthermore, HPE supplementation significantly decreased the MTX-elevated levels of the pro-inflammatory cytokines TNF-α, IL-6, and IL-10. Histopathological examinations showed that MTX produced severe cellular damage and inflammatory lesions in liver tissues, while treatment with HPE improved hepatic histologic architecture.

Conclusion

HPE has the ability to ameliorate methotrexate-induced liver injury in rats by mechanisms that include boosting antioxidative responses and down-regulating MDA and pro-inflammatory cytokine production.

Appropriate citation of placenta cell lines 3A(tPA-30-1) and 3A-sub E [post crisis of 3A(tPA-30-1)] in medical literature

Introduction

To determine how often placenta cell lines 3A (tPA-30-1) and 3A-sub E [post crisis of 3A (tPA-30-1)] are appropriately cited, or identified, as "term"-gestation placental cell lines in medical literature.

Methods

We performed a literature search on two databases, PubMed and One Search, using the terms "3A (tPA-30-1)," "3Asub-E," "3AsubE," "tPA-30-1," "tPA30-1," and "3A AND (placenta OR placental OR trophoblast OR trophoblastic) AND (cell OR line OR cell line)." Of the 218 citations retrieved, 181 were excluded due to duplication, article content irrelevance or lack of access to a full manuscript. The remaining 37 citations were thoroughly reviewed for 1)the presence of a full citation as designated by the supplier, and 2)the identification of the placental lines as "term."

Results

Of the 37 eligible citations included in the study, five demonstrated complete identifications of the placental cell lines of interest, while 32 demonstrated partial identifications that failed to match the designations provided by the manufacturer. Furthermore, of the 37 citations, eight accurately identified the cell lines as "term," while 27 lacked any description of gestational age, and two incorrectly identified them as "first trimester" cell lines. Overall, only three citations contained both a full citation and correct identification as a "term" placenta cell line.

Discussion

Only 5 of the 37 (13.5%) publications demonstrated a complete citation and only 8 publications accurately identified the gestational age of the placenta cell line as "term". Such findings confirm the need for a representative set of standards for the documentation of cell lines to improve the quality of publications in the scientific community.

New Insights into the Process of Placentation and the Role of Oxidative Uterine Microenvironment

For a successful pregnancy to occur, a predecidualized receptive endometrium must be invaded by placental differentiated cells (extravillous trophoblast cells (EVTs)) and, at the same time, continue decidualization. EVT invasion is aimed at anchoring the placenta to the maternal uterus and ensuring local blood supply increase necessary to provide normal placental and foetal development. The first is achieved by migrating through the maternal endometrium and deeper into the myometrium, while the second by transforming uterine spiral arteries into large vessels. This process is a tightly regulated battle comprising interests of both the mother and the foetus. Invading EVTs are required to perform a scope of functions: move, adhere, proliferate, differentiate, interact, and digest the extracellular matrix (ECM); tolerate hypoxia; transform the maternal spiral arteries; and die by apoptosis. All these functions are modulated by their surrounding microenvironment: oxygen, soluble factors (e.g., cytokines, growth factors, and hormones), ECM proteins, and reactive oxygen species. A deeper comprehension of oxidative uterine microenvironment contribution to trophoblast function will be addressed in this review.

Hepatocyte growth factor plays a particular role in progression of overall cardiac damage in experimental pulmonary hypertension

Background: HGF/MET pathway may have a role in pulmonary hypertension (PH). However, the link between the pathway and development of target organ damage in PH remains elusive. We aimed to demonstrate the relation between plasma HGF and HGF/MET tissue expressions in affected organs during PH progression. Methods: 12 weeks old male Wistar rats were injected with monocrotaline (MCT, 60 mg/kg, s.c.) to induce PH and sacrificed after 1, 2 and 4 weeks. Controls received saline. mRNA levels of HGF regulatory complex (Hgf, Met, Hgfa, Hai-1, Hai-2) were determined in right and left ventricles (RV, LV), lungs, pulmonary artery and liver by RT-qPCR. HGF protein levels in plasma were analysed by ELISA. Results: PH development was associated with a progressive elevation of HGF plasma levels that correlated with relative RV mass. Furthermore, Hgf mRNA expressions at week 4 were upregulated solely in the cardiac ventricles while being downregulated in a. pulmonalis, lungs and liver. Met and Hai-1/Hai-2 followed a similar pattern and were upregulated in cardiac ventricles, where Hgfa remained unchanged, but downregulated in lungs. Conclusion: We suggest that cardiac overexpression of Hgf might contribute to increased plasma HGF in MCT-induced PH. HGF could be exploited as a cardiospecific biomarker and HGF/MET pathway as a target in drug discovery for PH.

The Protective Effect of Sheep Placental Extract on Concanavalin A-induced Liver Injury in Mice

Though the biological effects of human placental extract have been widely studied, it has limited availability and its use poses ethical problems. Thus, domestic animal placental extracts are suggested as alternatives. In this study, the protective effect of sheep placental extract (SPE) on concanavalin A (Con A)-induced liver injury was investigated. BALB/c mice were randomly divided into six groups, including one normal group and five experimental groups, which received different oral doses of SPE (0, 5, 10 and 50 mg/kg) or a mixture of amino acids for 3 days before Con A injection. Compared with Con A-induced model group, the SPE administration significantly decreased serum aminotransaminase activity, alleviated pathological changes, recovered liver antioxidant capacity and prevented the increase of nitric oxide. Secretion of pro-inflammatory cytokines in serum decreased and mRNA expression of hepatic intercellular adhesion molecule-1, interferon-inducible chemokine 10 and inducible nitric oxide synthase were downregulated, while B-cell lymphoma-2 expression increased. The administration of amino acids mixture had no significant effect in most measurements compared with the model group, which indicated proteins and peptides, rather than individual amino acid, were largely responsible for the bioactivity of SPE. The results indicate SPE has potential therapeutic effects against immune-mediated hepatitis.

Effect of Human Placental Extract Treatment on Random-Pattern Skin Flap Survival in Rats

Background: Human placental extract (HPE), prepared from the placentas of healthy, postpartum females, displays various physiological activities, including antioxidative properties. In this study, a dorsal skin flap model was used to investigate the effect of HPE on flap viability in rats. Materials and methods: Forty male Sprague-Dawley rats underwent random-pattern skin flap surgeries. The animals were randomly divided among a control group and three treatment groups (localized injection (LI), 10 mg/kg/d localized HPE injections; low-dose treatment (LT), 10 mg/kg/d systemic HPE injections; high-dose treatment (HT), 40 mg/kg/d systemic HPE injections). Surviving skin flap areas were measured 7 days after surgery and tissue samples were stained with hematoxylin and eosin; vascular endothelial growth factor expression was determined immunohistochemically. To evaluate the antioxidant and antiapoptotic effects of HPE, malondialdehyde, glutathione peroxidase, and caspase-3 levels were examined. Results: Seven days after surgery, HPE-treated animals had significantly reduced necrotic areas, rats receiving the highest HPE dose demonstrated the greatest flap survival. In the HPE groups, the histopathological scores were lower than for the control group. Immunohistochemistry showed markedly more numerous vascular endothelial growth factor-positive cells in the HT group than in the C group. Malondialdehyde levels were significantly lower and glutathione peroxidase levels were higher in the HT group than in the C group. HPE treatment significantly inhibited apoptosis by lowering caspase-3 activity. Conclusions: HPE treatment yielded positive effects on flap survival, due to its antioxidant and antiapoptotic properties. These results suggest a new therapeutic approach for enhancing flap viability and accelerating wound repair.

Changes in Functional Activity of JEG-3 Trophoblast Cell Line in the Presence of Factors Secreted by Placenta

BACKGROUND AND AIMS

Cells in the maternal-fetal interface secrete cytokines that regulate proliferation, migration, and trophoblast invasion during the first trimester of pregnancy and the limitation of these processes during the third trimester. The aim of the study was to evaluate the influence of factors secreted by human placenta during the first and third trimester of pregnancy on cytokine receptor expression and proliferative and migratory activity of JEG-3 trophoblast cells.

METHODS

The research was conducted using the explant conditioned media of placentas obtained from healthy women with elective termination of pregnancy at 9-11 weeks and placentas of women whose pregnancy progressed without complications at 38-39 weeks. Assessment of surface molecule expression was performed using FACS Canto II flow cytometer (BD, USA). The proliferative activity of JEG-3 trophoblast cells was evaluated by dyeing with crystal violet vital dye. The migration activity of JEG-3 was evaluated using 24-well insert plates with polycarbonate inserts (pore size 8 microns).

RESULTS

Expression of CD116, CD118, CD119, IFNγ-R2, CD120b, CD183, CD192, CD295, EGFR, and TGFβ-R2 on JEG-3 was higher when the cells were incubated in the presence of the third trimester placental factors in comparison with the first trimester placental factors. Factors secreted by the placenta during the third trimester of pregnancy had more pronounced stimulatory effect on the proliferation and migration of trophoblast in comparison with baseline levels and with the effect of the first trimester placental factors.

CONCLUSIONS

The findings suggest that the behavior of trophoblasts in vitro might not be representative of in vivo behavior in the absence of additional local factors that influence the trophoblast in vivo.

c-Met-dependent multipotent labyrinth trophoblast progenitors establish placental exchange interface

The placenta provides the interface for gas and nutrient exchange between the mother and the fetus. Despite its critical function in sustaining pregnancy, the stem/progenitor cell hierarchy and molecular mechanisms responsible for the development of the placental exchange interface are poorly understood. We identified an Epcam(hi) labyrinth trophoblast progenitor (LaTP) in mouse placenta that at a clonal level generates all labyrinth trophoblast subtypes, syncytiotrophoblasts I and II, and sinusoidal trophoblast giant cells. Moreover, we discovered that hepatocyte growth factor/c-Met signaling is required for sustaining proliferation of LaTP during midgestation. Loss of trophoblast c-Met also disrupted terminal differentiation and polarization of syncytiotrophoblasts, leading to intrauterine fetal growth restriction, fetal liver hypocellularity, and demise. Identification of this c-Met-dependent multipotent LaTP provides a landmark in the poorly defined placental stem/progenitor cell hierarchy and may help us understand pregnancy complications caused by a defective placental exchange.

Hepatocyte growth factor regulates HLX1 gene expression to modulate HTR-8/SVneo trophoblast cells

BACKGROUND

Paracrine signaling of the hepatocyte growth factor (HGF) cytokine plays an important role in survival and invasion ability of placental trophoblasts. However, the intracellular factors and biological pathways underlying these responses remain unclear.

METHODS

This study investigated whether HGF affected the expression of homeobox gene HLX1, which is principally expressed in reproductive tissues and in some immune cells, and evaluated the implications of such in the HGF-induced human trophoblast cell line HTR-8/SVneo.

RESULTS

HGF was found to up-regulate both HLX1 mRNA and protein levels. Transient transfection of small interfering RNA (siRNA) targeting HLX1 abrogated its induction by HGF. Functionally, HLX1 siRNA not only reduced the growth and invasion capacities of HTR-8/SVneo cells at the basal level, but also inhibited these responses induced by HGF treatment.

CONCLUSIONS

HLX1 is an essential downstream signaling component of HGF that leads to growth and invasiveness of trophoblast cells.

Placenta extract promote liver regeneration in CCl4-injured liver rat model

The human placenta is an organ for fetus development and abundant reservoir of various bioactive molecules. Interest to human placenta extract (hPE) is growing, and application with trial of hPE is widening in oriental medicine including in liver diseases. However, underlying mechanisms for therapeutic effects are still unclear. Here, we investigated therapeutic effects of hPE in carbon tetrachloride (CCl(4))-injured rat liver model in vivo and in damaged rat hepatic cells exposed to CCl(4) in vitro. In addition, regulation of inflammatory responses by treatment of hPE was investigated. Serum levels of GOT/AST and GPT/ALT were significantly reduced (P<0.05), and uptake/excretion of indocyanine green in serum was significantly induced at 3 weeks after intravenous hPE administration in CCl(4)-injured rat model (P<0.05). Expression of type I collagen (Col I) and α-smooth muscle actin (α-SMA) was decreased, whereas that of matrix metalloproteinase-9 (MMP-9) was increased resulting in improvement of score for fibrotic grade in hPE group. Also, albumin, proliferation activities and molecules associated with liver regeneration (e.g. interleukin-6, gp130, ATP binding cassette transporters, cyclin A) were more increased in hPE administration group than Non-hPE group. hPE administration suppressed activated T-cell proliferation via increasing anti-inflammatory cytokines and decreasing pro-inflammatory cytokines. These results suggest that hPE could be effective for liver disease through reduction of fibrosis, induction of liver regeneration, and regulation of inflammatory responses. These findings are important for understanding the roles of hPE and provide evidences for therapeutic effects of hPE in hepatic diseases which could lead to potential clinical applications.

Syndecan-1 knock-down in decidualized human endometrial stromal cells leads to significant changes in cytokine and angiogenic factor expression patterns

BACKGROUND

Successful embryonic implantation depends on a synchronized embryo-maternal dialogue. Chemokines, such as chemokine ligand 1 (CXCL1), play essential roles in the maternal reproductive tract leading to morphological changes during decidualization, mediating maternal acceptance towards the semi-allograft embryo and induction of angiogenesis. Chemokine binding to their classical G-protein coupled receptors is essentially supported by the syndecan (Sdc) family of heparan sulfate proteoglycans. The aim of this study was to identify the involvement of Sdc-1 at the embryo-maternal interface regarding changes of the chemokine and angiogenic profile of the decidua during the process of decidualization and implantation in human endometrium.

METHODS

A stable Sdc-1 knock-down was generated in the immortalized human endometrial stromal cell line St-T1 and was named KdS1. The ability of KdS1 to decidualize was proven by Insulin-like growth factor binding 1 (IGFBP1) and prolactin (PRL) confirmation on mRNA level before further experiments were carried out. Dot blot protein analyses of decidualized knock-down cells vs non-transfected controls were performed. In order to imitate embryonic implantation, decidualized KdS1 were then incubated with IL-1beta, an embryo secretion product, vs controls. Statistical analyses were performed applying the Student's t-test with p < 0.05, p < 0.02 and p < 0.01 and one way post-hoc ANOVA test with p < 0.05 as cut-offs for statistical significance.

RESULTS

The induction of the Sdc-1 knock-down revealed significant changes in cytokine and angiogenic factor expression profiles of dKdS1 vs decidualized controls. Incubation with embryonic IL-1beta altered the expression patterns of KdS1 chemokines and angiogenic factors towards inflammatory-associated molecules and factors involved in matrix regulation.

CONCLUSIONS

Sdc-1 knock-down in human endometrial stroma cells led to fulminant changes regarding cytokine and angiogenic factor expression profiles upon decidualization and imitation of embryonic contact. Sdc-1 appears to play an important role as a co-receptor and storage factor for many cytokines and angiogenic factors during decidualization and implantation period, supporting proper implantation and angiogenesis by regulation of chemokine and angiogenic factor secretion in favour of the implanting embryo.

Laennec protects murine from concanavalin A-induced liver injury through inhibition of inflammatory reactions and hepatocyte apoptosis

The effect of Laennec, a hydrolyte of human placenta, on immune-mediated liver injury was investigated in vivo and in vitro in murine. Vena caudalis administration of concanavalin A (Con A) was employed to establish an in vivo liver-injury model, and in vitro hepatotoxicity was induced by 8 h interaction between Con A pre-treated hepatocytes and Con A-stimulated autologous splenic lymphocytes. Laennec was used for pre-treatment in the two models. Laennec decreased biochemical marker activity (alanine aminotransferase, ALT; lactate dehydrogenase, LDH) in serum and recovered the activity of superoxide dismutase (SOD) and myeloperoxidase (MPO), as well as the content of malondialdehyde (MDA) and nitric oxide (NO) in liver tissue. We also found that the DNA ladder induced by Con A in vivo was attenuated by Laennec. Furthermore, the leakage of aspartate aminotransferase (AST) and LDH in the supernatant of the co-culture system was decreased by addition of Laennec. Potential protective mechanisms were elucidated by DNA fragmentation assay and intercellular adhesion molecule-1 (ICAM-1) induction/inhibition experiments. Results showed that ICAM-1, which is related to the interaction between hepatocytes and lymphocytes, was inhibited by Laennec. These findings indicated that Laennec has potent activity against immune-mediated liver injury.

Defective implantation and placentation: laying the blueprint for pregnancy complications

Normal implantation and placentation is critical for pregnancy success. Many pregnancy-related complications that present late in gestation (such as pre-eclampsia and preterm labour) appear to have their origins early in pregnancy with abnormalities in implantation and placental development. Implantation is characterized by invasion of the maternal tissues of the uterus by fetal trophoblast, and the degree to which trophoblast invades these tissues appears to be a major determinant of pregnancy outcome. Excessive invasion can lead to abnormally firm attachment of the placenta to the myometrium (placenta accreta) with increased maternal and perinatal morbidity. Inadequate invasion, specifically restricted endovascular invasion, has been implicated in the pathophysiology of such conditions as pre-eclampsia (gestational proteinuric hypertension), preterm premature rupture of membranes, preterm labour, and intrauterine growth restriction. The molecular and cellular mechanisms responsible for implantation remain enigmatic. This review will include an overview of implantation followed by a discussion of a number of molecular mechanisms implicated in defective implantation and placentation including the role of decidual prostaglandins and haemorrhage in regulating trophoblast invasion. An improved understanding of the molecular mechanisms responsible for abnormal implantation and placentation will likely improve clinicians' abilities to treat disorders that occur along this continuum, including infertility, recurrent pregnancy loss, pre-eclampsia, and preterm birth.

Human decidual production of hepatocyte-growth factor is not influenced by trophoblastic invasion in vivo

OBJECTIVE

To evaluate and compare production of hepatocyte growth factor (HGF) from human first-trimester implantation-site decidua (decidua basalis) and nonimplantation site decidua (decidua parietalis), and hence to determine whether human trophoblast invasion in vivo is associated with increased decidual HGF production.

DESIGN

Controlled prospective study.

SETTING

University hospital-based study.

PATIENT(S)

Ten women undergoing first-trimester termination of singleton pregnancy for psychosocial reasons without preexisting medical or gynecologic diseases.

INTERVENTION(S)

Decidual samples surgically excised and processed for paraffin-embedded immunohistochemistry and for reverse transcription-polymerase chain reaction (RT-PCR) studies.

MAIN OUTCOME MEASURE(S)

Protein and mRNA production in decidua basalis and decidua parietalis by immunohistochemistry and RT-PCR, respectively.

RESULT(S)

No statistically significant difference was found between decidua basalis and decidua parietalis in HGF protein or mRNA production. Immunohistochemical analysis (n = 9) showed a mean score of 3.28 +/- 2.37 for decidua basalis and 3.61 +/- 2.66 for decidua parietalis. Semiquantitative analysis of HGF mRNA expression between the two sites showed no statistically significant difference (n = 10)

CONCLUSION(S)

Human decidual production of HGF is not influenced by trophoblastic invasion in vivo.

Expression and activation of MAP kinases, ERK1/2, in the human villous trophoblasts

Mitogen-activated protein kinase (MAP kinase) plays a central role in the signal transduction for diverse cellular responses, such as proliferation, differentiation, stress response and cell death, via activation after binding of growth factors to the respective receptors on the cell membrane. In the human placental tissues, however, little is known about the expression and activation of the classical MAP kinases, extracellular signal-regulated kinase1/2 (ERK1/2). We therefore examined the expression of ERK1/2 in the human chorionic and placental tissues between 5 and 41 weeks of gestation, using Western blotting, immunohistochemistry and in situ hybridization. To explore the activation of ERK1/2 protein, we used an antibody that reacts with both phosphorylated and non-phosphorylated ERK1/2 (total ERK1/2), as well as antibodies that react only with phosphorylated ERK1/2. The expression pattern of phosphorylated ERK1/2 in the trophoblasts was compared with that of various growth factor receptors, such as c-met, IGF-1R, flt-1, EGFR, PDGFR, Bek, and flg. Total ERK1/2 was immunolocalized in the villous cytotrophoblasts (CTs), but not in the syncytiotrophoblasts (STs), throughout pregnancy. In situ hybridization also showed the localization of ERK1 mRNA in the villous CTs. Interestingly, however, phosphorylated ERK1/2 was immunolocalized in the villous CTs only up to 12 weeks of gestation. Western blot also showed the stronger bands of phosphorylated ERK1/2 in the tissues of the first trimester. Among the growth factor receptors, c-met was strongly expressed in the villous CTs during the first trimester, and resembled the expression pattern of phosphorylated ERK1/2. These findings suggest that the MAP kinase pathway is activated in the villous CTs during the first trimester in the human placenta.

Regulation of human cytotrophoblast morphogenesis by hepatocyte growth factor/scatter factor

In vitro morphogenesis of epithelial cells to form tube-like structures is regulated by hepatocyte growth factor-scatter factor (HGF/SF). The placenta is a rich source of HGF/SF, and its absence in mice has been shown to lead to impaired placental growth and embryonic death. There is no information in the literature regarding in vitro morphogenesis of human cytotrophoblasts or the effect of HGF/SF on this process. In this study, cytotrophoblasts were isolated from human placentae obtained from all three trimesters of gestation and cultured on the recombinant basement membrane matrix (Matrigel). Under these conditions, cytotrophoblasts participated in morphogenetic events including formation of spheroid-like structures, radial linear processes with branching, and invaded Matrigel and formed large, tube-like structures. The presence of a developing lumen was documented in the linear projections arising from spheroids and in the tube-like structures by both confocal and transmission electron microscopy. Immunohistochemistry was used to characterize the phenotype of the cells, and staining with anti-cytokeratin and anti-E-cadherin antibodies confirmed the presence of cytotrophoblasts in both the spheroids and tube-like structures. Recombinant HGF (rHGF) significantly increased the invasive activity of cytotrophoblasts isolated from the first and second (P < 0.001) and third trimesters (P < 0.01). In addition, rHGF significantly increased the percentage of spheroids with branching processes in the first and second trimesters (P < 0.05). Anti-HGF antibody inhibited both these effects in a dose-dependent manner, indicating the specificity of the above findings. This study provides new evidence indicating that HGF/SF regulates invasion and branching morphogenesis of cytotrophoblasts throughout gestation, with maximum effects in the first and second trimester. These findings may help to elucidate the importance of the reduced expression of HGF/SF identified in placentae from women with preeclampsia or intrauterine growth restriction and suggest that HGF/SF may serve as an important candidate in therapeutic intervention strategies.

Hepatocyte growth factor activator (HGF-A) and its zymogen in human placenta

HGF-activator (HGF-A) is a circulating serine protease known to be responsible for activation of hepatocyte growth factor (HGF). Active HGF is thought to be an important regulator of trophoblast growth. In vitro, HGF-A is produced via proteolytic cleavage of its zymogen by thrombin. Immunocytochemistry and Western immunoblotting were performed using human placental tissue from all three trimesters with an antibody that recognizes both HGF-A and its zymogen. Western immunoblotting revealed a 97 kDa band equivalent to the zymogen in placenta from all three trimesters. A smaller 34 kDa band equivalent to HGF-A was only seen in first and second trimester placenta. The anti-HGF-A/zymogen antibody demonstrated immunostaining in placental villi and membranes throughout gestation. Within first trimester villi immunostaining was strongest within the syncytio- and cytotrophoblast layers, but was also seen within stromal and endothelial cells. Likewise, in third trimester placenta the syncytio-cytotrophoblast layer showed the strongest immunoreactivity. In vitro, HGF can induce trophoblast DNA synthesis and the localization of HGF-A to the peri-villous trophoblast layer (which expresses c-met, the HGF receptor) suggests that it may be responsible for activation of pro-HGF at this site. This adds further weight to the hypothesis that HGF in vivo is an important regulator of trophoblast growth.

A role for hepatocyte growth factor during early postimplantation growth of the placental lineage in mice

Hepatocyte growth factor (HGF) is implicated in placental development; hgfr and hgf null mutant embryos develop placental insufficiency and lethality at 11.5 days (E11.5) after fertilization. The function of HGF in placentation at implantation (E4.5) has not been studied. Using reverse transcription-polymerase chain reaction, we detected HGF receptor (HGFR) mRNA in preimplantation embryos and in cultured blastocyst outgrowths. HGFR protein was detected in trophoblast cells in blastocyst outgrowths. HGF mRNA was not detected at these stages but was detected in the uterus at E5.5. Using in situ hybridization, we detected HGF mRNA in the mesometrial uterus, near the embryo, from E6.5 through E8.5. At E8.5, HGFR mRNA was detected in the chorionic placenta, and HGF mRNA was detected in the allantois. The expression for HGF and HGFR suggested a maternal-to-embryonic communication before the development of the allantois. To test this, blastocyst outgrowths were cultured with HGF. HGF stimulated the outgrowth of trophoblasts in a time-dependent manner and stimulated the expression of proliferating cell nuclear antigen, but it did not scatter trophoblasts. HGF stimulated an increase in the trophoblast cell number, but caused a decrease in the total number of terminally differentiated trophoblasts expressing placental lactogen-1 protein. These data suggest that HGF stimulates the cell division, but not the differentiation, of trophoblast cells during implantation.

Expression and action of hepatocyte growth factor in human and bovine normal ovarian surface epithelium and ovarian cancer

More than 95% of ovarian cancers originate from the epithelial cells on the surface of the ovary, which are termed ovarian surface epithelium (OSE). These OSE cells are modified peritoneal mesothelial cells separated from underlying ovarian surface stromal tissue by a basal lamina of dense collagenous connective tissue. Mesenchymal-epithelial cell interactions between stromal cells and OSE cells are postulated to be important for normal OSE biology and for the onset of ovarian cancer. Hepatocyte growth factor (HGF) is a mesenchymal-derived growth factor that mediates mesenchymal-epithelial cell interactions in a number of different tissues. The current study was an investigation of the expression and actions of HGF in normal OSE and ovarian cancer. Human epithelial cells from borderline and stage III ovarian cancer cases were found to express HGF protein in the epithelial cell component by immunocytochemistry analysis. The stromal cell component of human ovarian tumors contained little or no HGF immunostaining. Normal bovine ovaries have a similar physiology and endocrinology to human ovaries and are used as a model system to investigate normal OSE functions. HGF protein was detected in the OSE from both normal human and bovine ovaries. Adjacent ovarian stromal tissue contained light but positive HGF immunostaining. RNA was collected from normal bovine ovarian stromal cells to examine HGF gene expression. HGF transcripts were detected in cultured OSE and stromal cells by Northern blot analysis. Using a quantitative reverse transcription-polymerase chain reaction procedure, HGF gene expression was found to be high in freshly isolated OSE but low in freshly isolated stroma. Levels of HGF gene expression after culture of stroma increased. Observations indicate that normal OSE express high levels of HGF in vivo and in vitro. Expression of HGF by normal epithelial cells versus stromal cells was unexpected and suggests that HGF may be important in an autocrine regulation of OSE. HGF actions on normal OSE cells and ovarian cancer cells were investigated. HGF was found to stimulate the growth of normal OSE cells in a manner similar to such growth stimulated by epidermal growth factor. Two ovarian cancer cell lines, SKOV3 and OCC1, were also stimulated to grow in response to HGF. This observation suggests that HGF may be involved in sustaining growth of ovarian tumors. These results are the first to demonstrate the production and action of HGF in normal OSE cells and ovarian cancer cells. This appears to be an example of HGF production by an epithelial cell, such that a mesenchymal-epithelial mixed phenotype is present. The autocrine stimulation of OSE growth by the local production and action of HGF provides insight into how the OSE may develop abnormal growth characteristics involved in the onset and progression of ovarian cancer.

Hepatocyte growth factor/scatter factor-induced intracellular signalling

Hepatocyte growth factor (HGF) identical to scatter factor (SF) is a glycoprotein involved in the development of a number of cellular phenotypes, including proliferation, mitogenesis, formation of branching tubules and, in the case of tumour cells, invasion and metastasis. This fascinating cytokine transduces its activities via its receptor encoded by the c-met oncogene, coupled to a number of transducers integrating the HGF/SF signal to the cytosol and the nucleus. The downstream transducers coupled to HGF/MET, most of which participate in overlapping pathways, determine the development of the cell's phenotype, which in most cell types is dual.

Hepatocyte growth factor stimulates trophoblast invasion: a potential mechanism for abnormal placentation in preeclampsia

Hepatocyte growth factor (HGF) is a cytokine that is produced in the placental villous core and acts in a paracrine manner on trophoblasts that express the HGF receptor Met. Because HGF stimulates the invasion of many epithelial cell types, villous core HGF could regulate placental trophoblast invasion. As preeclampsia is characterized by inadequate trophoblast invasion, we investigated the hypothesis that decreased placental HGF production is a mechanism for inadequate trophoblast invasion in this disease. Placental villous explant HGF production over 24 h was 25% lower in patients with preeclampsia (n = 5; 7.29 +/- 0.8 ng/mL) than in normal patients (n = 5; 9.76 +/- 0.5 ng/mL; P < 0.05). The human first trimester trophoblast cell line (ED27) used in subsequent invasion studies was found to express c-met messenger ribonucleic acid by RT-PCR and Met protein by Western analysis, and underwent phosphorylation of tyrosine residues on Met with HGF exposure. A Boyden chamber invasion assay using collagen type I showed that HGF caused a specific dose-response increase in trophoblast invasion first seen at 10 ng/mL (2.2-fold increase; P < 0.05). The stimulation of trophoblast invasion by HGF may in part be due to the 2-fold induction of 92-kDa collagenase as determined by zymogram analysis of the trophoblast-conditioned medium. These studies suggest that HGF has an important role in placental trophoblast invasion through the activation of Met and the subsequent induction of 92-kDa collagenase in these cells. In addition, decreased placental production of HGF in preeclampsia provides a potential mechanism for the lack of trophoblast invasion that is seen in this pregnancy disorder.

Stimulation of DNA synthesis in trophoblasts and human umbilical vein endothelial cells by hepatocyte growth factor bound to extracellular matrix

Hepatocyte growth factor (HGF) promotes the growth not only of hepatocytes but also of several other types of cells such as cytotrophoblasts and endothelial cells. Recent studies have revealed that HGF is trapped in the extracellular (ECM) matrix through heparan sulphate in vivo, thereby acting as a mitogen for hepatocytes in cooperation with heparan sulphate. In this study, we detected HGF protein in chorionic tissue and placental tissue extracts, and found that HGF and heparan sulphate were co-distributed in the endothelial basement membrane and trophoblast basement membrane on immunohistochemical examination. The rates of DNA synthesis in primary cultured cytotrophoblasts and human umbilical vein endothelial cells (HUVEC) cultured on HGF-bound Matrigeltrade mark were 6-8 times those of control cytotrophoblasts and HUVEC. When Matrigeltrade mark dishes were pretreated with heparinase and heparitinase prior to binding of HGF, stimulation of DNA synthesis was markedly decreased. A considerable decrease in stimulation of DNA synthesis was observed following washing of HGF-bound Matrigeltrade mark with 1 m acetic acid, 1 m NaCl and 0.1 per cent trypsin, but not following treatment with chondroitinase ABC. These observations suggest that HGF can be trapped in ECM in vivo, thereby acting as a mitogen for cytotrophoblasts and placental vein endothelial cells in cooperation with heparan sulphate.

Distribution of Th1, Th2, and Th0 and the Th1/Th2 cell ratios in human peripheral and endometrial T cells

PROBLEM

To examine whether normal pregnancy involves type 2 T-helper (Th2) immune condition or not.

METHOD OF STUDY

We measured the percentage of Th0, Th1, and Th2 and the Th1/Th2 cell ratios of human peripheral blood and endometrial T cells using flow cytometry, which can analyze both the surface marker CD3, and intracellular cytokines, interleukin 4 (IL-4) and interferon gamma (IFNgamma).

RESULTS

No significant differences were found in the percentages of Th1, Th2, and Th0 and the Th1/Th2 cell ratios in the peripheral blood T cells of nonpregnant women and women in early pregnancy. On the other hand, the percentage of Th1 cells was highest during the proliferative phase of the endometrium, followed by the secretory phase and early pregnancy decidua. The percentage of Th2 cells was highest in early pregnancy decidua and lowest during the proliferative phase of the endometrium. The Th1/Th2 ratio was 147.48+/-96.68 during the proliferative phase of the endometrium, 37.74+/-21.33 during the secretory phase, and 1.31+/-0.48 in the early pregnancy decidua.

CONCLUSIONS

These data indicate that Th1 cells predominate in the nonpregnant endometrium, especially during the proliferative phase, while Th2 cells predominate in early pregnancy decidua.

Hepatocyte growth factor levels during normal and intra-uterine growth-restricted pregnancies

Hepatocyte growth factor (HGF), also known as scatter factor, binds the c-met receptor. It has been shown to be involved in mesenchyme-epithelial interactions. HGF is produced by the villous mesenchyme of the placenta throughout pregnancy and its receptor located on the villous cytotrophoblast cells. In this study the levels of HGF were measured in consecutive samples of plasma taken from pregnant women. Normal pregnancies were compared with intrauterine growth restricted (IUGR) pregnancies (below the third centile). In both groups, the levels of HGF were found to increase significantly as pregnancy progressed and then fall post partum. There was a considerable amount of variation found between individual women but no significant difference (P=0.65) between the normal and IUGR pregnancies.

Hepatocyte growth factor and the kidney: it is not just for the liver

Mesenchymal-epithelial interactions are important for many biological processes in epithelial organs such as the kidney. Hepatocyte growth factor (HGF) is a mesenchymally derived polypeptide cytokine that acts through its tyrosine kinase c-met receptor and is an important mediator of these interactions. This article reviews data showing the in vitro actions of HGF on renal epithelial cells that result in such diverse responses as mitogenesis, motogenesis, and morphogenesis. It also examines the in vivo evidence linking HGF and the c-met receptor to kidney development, regeneration following injury, and renal disease. Elucidating cellular mechanisms underlying the coordinated control of diverse HGF-induced phenotypic changes in renal epithelia in vitro should contribute to a clearer understanding of complex biological processes such as organogenesis, regeneration, and carcinogenesis in epithelial organs such as the kidney.

Ontogeny of hepatocyte growth factor (HGF) and its receptor (c-met) in human placenta: reduced HGF expression in intrauterine growth restriction

Severe intrauterine growth restriction (IUGR) is characterized by abnormal placentation. Mouse gene knockout studies show that an absence of either hepatocyte growth factor (HGF) or its receptor, c-met, leads to intrauterine death secondary to severe IUGR with deficient placentation. In this study, immunocytochemistry localized HGF protein throughout placental villi across gestation, whereas c-met protein was localized only to the perivillous trophoblast and vascular endothelium. Within the IUGR placentae, a reduction in HGF immunostaining within the villous stroma was observed. HGF mRNA was strongly expressed in the perivascular tissue around the stem villous arteries throughout gestation, with weaker expression within the villous stroma and the terminal villi. c-met mRNA expression was limited to the perivillous trophoblast, particularly in the first trimester, with only a faint hybridization signal from the villous stroma. Placental mRNA expression was examined quantitatively using a ribonuclease protection assay: HGF and c-met mRNA expression increased from the first to the second trimester, reaching a zenith before decreasing again through the third trimester to term. HGF mRNA levels were significantly reduced in the IUGR placentae (P = 0.036), whereas c-met mRNA expression was within the normal range for gestation. These findings suggest that HGF derived from the perivascular tissue of stem villous arteries may play an important role in controlling normal villous development. Whereas reduced expression of HGF within IUGR placentae does not prove a causative link with abnormal villous development, the association lends support to this possibility.

Developmental and hormonal regulation of hepatocyte growth factor expression and action in the bovine ovarian follicle

Ovarian hormones (i.e., estrogen and LH) may promote folliculogenesis by regulating the local production of mesenchymal "inducer proteins" that mediate theca cell-granulosa cell interactions. Theca cells produce hepatocyte growth factor (HGF) that can stimulate granulosa cell growth. In order to investigate the physiological role of HGF in the ovarian follicle, the developmental and hormonal regulation of HGF was examined during follicular development in the bovine ovary. Reverse transcription-polymerase chain reaction (RT-PCR) analysis was used to examine HGF expression in theca cells and the HGF receptor (HGFR or c-met) in granulosa cells. Both HGF and HGFR were detected throughout follicular development in small (< 5 mm)-, medium (5-10 mm)-, and large (> 10 mm)-sized follicles. Steady-state levels of HGF and HGFR mRNAs were determined using sensitive quantitative RT-PCR assays. Developmental regulation of HGF in theca cells and HGFR in granulosa cells was analyzed in freshly isolated small-, medium-, and large-sized follicles. Observations demonstrate that expression of HGF (in theca cells) and HGFR (in granulosa cells) was highest in large-sized follicles. Hormonal regulation of HGF was analyzed in hormone-treated theca cell cultures. Steady-state levels of HGF mRNA in theca cells were increased by treatment with hCG (an LH agonist), but estradiol had no effect. These results suggest that LH may promote ovarian follicular growth (i.e., granulosa cell proliferation) in part by stimulating the local production of HGF by theca cells. Effects of HGF on granulosa cell differentiated functions were examined. Treatment with HGF reduced basal and FSH-stimulated levels of aromatase activity in bovine and rat granulosa cells. In addition, HGF inhibited the ability of hCG to stimulate progesterone production by granulosa cells. The inhibition of granulosa cell steroid production by HGF is proposed to be the indirect effect of promoting cellular proliferation. Therefore, HGF directly stimulates granulosa cell proliferation and indirectly inhibits granulosa cell differentiated functions. The developmental and hormonal regulation of HGF and HGFR during folliculogenesis provides evidence that HGF may be important for hormone-induced granulosa cell proliferation. As a result, HGF may be essential for establishing the granulosa cell population and microenvironment required for oocyte maturation in the female.

Hepatocyte growth factor in human breast milk

PROBLEM

The purposes of this study were to investigate the presence of hepatocyte growth factor (HGF) in human milk, to identify the cells that produce HGF in human milk, and to determine the contribution of HGF to the growth of neonates.

METHOD OF STUDY

The HGF concentrations in serum and whey were determined with an enzyme-linked immunosorbent assay kit. The presence of HGF in whey was also examined by Western blot analysis. To determine which cells in human milk produce HGF, an immunohistochemical examination was conducted. The expression of HGF mRNA in the mononuclear cells in human milk was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). The effects of whey and of recombinant HGF (rHGF) on DNA synthesis by a rat small intestinal cell line, IEC-6, were examined by [3H]thymidine uptake.

RESULTS

Human colostrum whey contained 2.22 +/- 1.02 ng of HGF/ml. Milk whey collected 1 month later contained 1.83 +/- 1.03 ng of HGF/ml. The presence of the heterodimeric form of HGF in colostrum whey was demonstrated by Western blot analysis. HGF was detected in the cytoplasm of human milk macrophages by an immunohistochemical examination, and the RT-PCR also revealed that HGF mRNA is expressed in the mononuclear cells of human milk. DNA synthesis by IEC-6 cells was increased by rHGF treatment and by whey treatment. The effect of whey on DNA synthesis by IEC-6 cells was partially, but significantly, decreased by anti-human HGF-neutralizing antibody treatment.

CONCLUSIONS

Human milk contains a large amount of the active form of HGF, produced by macrophages, and HGF in human milk induces the growth of intestinal cells. Our data suggest that HGF in human milk is one of the important factors regulating the growth of intestinal cells in neonates after birth.

Prevalence of the partial molar phenotype in triploidy of maternal and paternal origin

Triploid partial moles are at risk for trophoblastic neoplasia, yet the prevalence, parent of origin, and evolution of the partial molar phenotype amongst all triploids remains controversial. We determined parental origin by polymerase chain reaction (PCR) analysis, stage of development by gross and histological criteria, and partial molar status according to strict diagnostic criteria for all triploids identified amongst 1,054 consecutively karyotyped spontaneous abortions. Triploidy was detected in 64 of 832 successfully karyotyped specimens. Complete data were collected in 59 cases. Diandric origin was found in 39 specimens, and 20 of these fulfilled all four criteria for partial mole (trophoblast hyperplasia, dimorphic population of large and small villi, villous hydrops greater than 0.5 mm, and irregular villous contour). We separated the 19 diandric triploids not fulfilling all criteria for partial mole into four groups: specimens of early developmental stage, which we believed represented developing ("early") partial moles (n = 3), cases of late developmental stage, which we believed represented involuting ("ancient") partial moles (n = 4), cases showing some but not all criteria for partial mole (n = 7), and specimens with few if any criteria suggestive of partial mole (n = 5). In triploids of digynic origin (n = 20), developmental stage was significantly lower, fetal tissue was more frequently identified, and all specimens showed well-preserved fetal red blood cells. Digynic triploids occasionally showed irregular contour, dimorphic villi, and a mild form of trophoblast hyperplasia but never showed hydropic degeneration and were never suspicious for partial mole.

Expression of hepatocyte growth factor/scatter factor and its receptor, MET, suggests roles in human embryonic organogenesis

Hepatocyte growth factor/scatter factor (HGF/SF) is secreted by mesenchymal cells and elicits proliferation, motility, differentiation, and morphogenesis of epithelia and other cells. These effects are mediated by binding to MET, a receptor tyrosine kinase. Genetically engineered mice lacking HGF/SF die in utero due to a failure of placental and hepatocyte differentiation, but little information exists regarding the expression of this signaling system in human development. Using reverse transcriptase-polymerase chain reaction, Western blots, and immunohistochemistry, we report that HGF/SF and MET are expressed during critical early periods of human organogenesis from 6 to 13 wk of gestation. Organs that expressed both genes included liver, metanephric kidney, intestine, and lung, each of which develop by inductive interactions between mesenchyme and epithelia. Of all organs studied, the placenta contained the highest levels of HGF/SF protein, and MET was detected in trophoblastic cells of chorionic villi as early as the 5th wk of gestation. Finally, examination of a human multicystic dysplastic kidney demonstrated that malformed, hyperproliferative tubules expressed MET, whereas HGF/SF protein was immunolocalized to the same epithelia and also to the surrounding undifferentiated cells. Hence HGF/SF might be an important growth factor in normal human embryogenesis and may additionally play a role in human organ malformations.

The differential expression of hepatocyte growth factor and met in human placenta

Met is the tyrosine kinase receptor for the ligand hepatocyte growth factor (HGF). Met/HGF plays an important role in epithelial cell proliferation, migration, and morphogenesis. HGF also plays a crucial role in placental development in the mouse. To determine whether HGF potentially has a similar role in human placental development, the production and localization of Met and HGF were determined in early second trimester and term placentas. Reverse transcription-PCR using specific primers demonstrated the expression of Met and HGF messenger ribonucleic acid in placental villi. HGF production was determined by enzyme-linked immunosorbent assay. HGF production over 48 h by second trimester placental villous explants in culture (810 pg/mg total protein x h) was 2.1-fold greater than that in term placental villous explants (380 pg/mg total protein x h; P < 0.01). Isolated trophoblast did not produce HGF, whereas isolated villous core tissues and villous core mesenchymal cells did produce HGF. Interleukin-1 beta treatment of placental villi or coculture of villous core mesenchymal cells with isolated trophoblast cells did not stimulate HGF production. Using immunohistochemistry, HGF localized to the villous core compartment with no localization to the trophoblast. In contrast, Met localized mainly to cytotrophoblast. These findings suggest that HGF produced by the villous core may act in a paracrine fashion to regulate trophoblast development or function through the HGF receptor, Met.

Immunoreactivity for hepatocyte growth factor/scatter factor and its receptor, met, in human lung carcinomas and malignant mesotheliomas

Paraffin sections from 29 lung carcinomas (28 primary and 1 metastatic) and 9 pleural malignant mesotheliomas were immunostained with antisera to human hepatocyte growth factor/scatter factor (HGF/SF) and its receptor, met. For HGF/SF, immunoreactivity was demonstrated in all 9 mesotheliomas, 9 of 12 adenocarcinomas, and 7 of 10 squamous cell carcinomas. None of seven cases of small cell anaplastic carcinoma was positive. The adenocarcinomas frequently showed enhanced luminal staining, suggesting possible secretion of HGF/SF, and this pattern of staining was also seen occasionally in bronchial epithelium adjacent to the tumour. Stromal fibroblasts also showed immunoreactivity for HGF/SF in 6/8 cases of mesothelioma but in only 3/12 adenocarcinomas, 1/10 squamous cell carcinomas, and 1/4 small cell anaplastic carcinomas. All tumours stained for met, usually strongly. The staining was mainly cytoplasmic in nature, but some plasma membrane staining was usually evident. Adenocarcinomas showed strong luminal membrane staining, as did adjacent, histologically normal bronchial epithelium. This study demonstrates the presence of HGF/SF and met in most of the tumour types described, particularly mesotheliomas, and suggests that the HGF/SF/met signalling system may play a role in the development of these tumours, either by autocrine or by paracrine mechanisms.