Uptake and processing of 125I-labelled transferrin and 59Fe-labelled transferrin by isolated human trophoblast cells

Trophoblast cells isolated from term human placenta and maintained as an adherent culture express surface receptors for transferrin as indicated by quantitative binding studies using 125I-labelled transferrin. The Kd was 5.3 x 10(-9) M. About 36 per cent of the total cell receptor population was found at the cell surface, the remainder being intracellular. Both 125I-labelled and 59Fe-labelled transferrin were internalized by receptor-mediated endocytosis with similar rates. Pulse-chase experiments showed that 125I-labelled transferrin was recycled and released back to the medium, whereas 59Fe accumulated intracellularly and was released slowly. Polyacrylamide gel electrophoresis followed by autoradiography revealed that 59Fe was accumulated by cells largely in the form of ferritin. A small intracellular pool of low molecular weight 59Fe was also detected. In the presence of monensin, the transfer of 59Fe to ferritin was greatly reduced. The nature and amount of 59Fe released from cells could be modulated by the incubation conditions. In the absence of chelating agents and iron salts, released 59Fe was found to be associated with a low molecular weight fraction as well as with transferrin and ferritin. The low molecular weight 59Fe readily formed a complex with added chelators such as apotransferrin, DTPA or desferrioxamine. The release of 59Fe could be increased by repeatedly changing the medium during the course of the incubation. 59Fe release from trophoblast cells exceeded the release of lactate dehydrogenase and also exceeded the release of 59Fe from 3T3 fibroblasts, suggesting a cell-specific process.     

Expression of transferrin receptors during differentiation of human placental trophoblast cells in vitro.

In most cell types, transferrin receptor expression is correlated with the proliferation rate, being increased by growth stimulation, or decreased by induction of terminal differentiation. In the human placenta the multinucleated syncytiotrophoblast, in direct contact with maternal blood, is derived by differentiation from mononucleated cytotrophoblast. In this study we examined changes in transferrin receptor expression during in vitro differentiation of trophoblast. Cells cultured in Ham's/Waymouth's medium (HWM) remained primarily mononuclear throughout the study, whereas incubation in keratinocyte growth medium (KGM) led to formation of multinucleate masses within 2-3 days of culture. Cell surface binding of 125I-labelled transferrin increased fivefold between days 1-5 of culture in both media and surface receptors were saturated at 7-14 micrograms/ml (90-200 fM). At saturation, the amount of transferrin bound to syncytiotrophoblast was 37 per cent lower than in cytotrophoblast. Scatchard analysis revealed a reduction in the number of surface transferrin receptors in syncytiotrophoblast compared to cytotrophoblast. A corresponding 29 per cent reduction in the binding of transferrin to intracellular sites was observed in syncytiotrophoblast. Distribution of receptors between surface and intracellular sites was therefore similar in both cytotrophoblast and syncytiotrophoblast. The affinity of transferrin for transferrin receptors was 3.7-fold higher in syncytiotrophoblast when compared to cytotrophoblast. Observed differences between the two cell types were not due to the presence of growth factors or higher iron levels in KGM. Expression of a high number of surface transferrin receptors in syncytiotrophoblast (1.5 x 10(12)/mg protein), along with a high affinity of these receptors for iron-saturated transferrin, could help explain the efficient transport of large amounts of iron from mother to fetus.     

Survivin Ki67在卵巢原发癌与转移癌中的表达及其临床意义

目的研究卵巢原发癌和转移癌组织中SurvivinmRNA、Ki67蛋白表迭的相关关系及临床意义。方法对1985—2002年中国医科大学附属一院妇科收治的38例卵巢原发癌、36例卵巢转移癌、16例卵巢良性肿瘤病例组织标拳及10例正常卵巢组织运用原住杂交技术检测SurvivinmRNA的表达．免疫组化SP法检测Ki67蛋白标记指数，并对其与临床各因素关系进行综合分析。结果Survivin、Ki67在卵巢原发癌和转移癌组织中的表达水平明显高于正常卵巢及良性卵巢肿瘤组织（P〈0．01）。Ki67表达与年龄及有无淋巴结转移无关，与卵巢原发癌和转移癌的临床分期、分化程度及卵巢转移癌的预后密切相关。Survivin表达与K167表达具有一定关联性，呈正相关关系（r=0．498）。结论Survivin和Ki67的高表达在卵巢原发癌厦转移癌的发生发展中有协同作用，可作为评价卵巢肿瘤生物学行为的重要依据，并可评估卵巢肿瘤恶性程度的重要参考指标。     

Expression of interleukin-27 by human trophoblast cells

Cytokines produced at the fetal-maternal interface play a key role in regulating maternal tolerance to the fetus and successful pregnancy. Previously, we showed that EBV-induced gene 3 (EBI3), an interleukin (IL)-12 p40 homologue, was expressed at very high levels by syncytiotrophoblasts and extravillous trophoblasts throughout human pregnancy. EBI3 was recently shown to associate with a novel ligand, p28, to form a new heterodimeric cytokine with important immunoregulatory functions, IL-27. In this study, we investigated whether EBI3 expression by trophoblast cells is associated with that of p28 to form IL-27. We found that genes encoding IL-27 (EBI3 and p28) and its receptor (IL-27R and gp130) were expressed in the placenta at various stages of pregnancy. Co-immunoprecipitation experiments performed from placental lysates, and ELISA of culture supernatants from placental explants, showed that IL-27 heterodimer was produced and released from placental cells. In situ studies of placentae of first, second and third trimester of pregnancy, and of choriocarcinomas, demonstrated that syncytiotrophoblast cells co-expressed EBI3 and p28. Similarly, extravillous trophoblast cells invading the decidua were found to co-express both subunits of IL-27. These data suggest that IL-27 may be part of the cytokine network regulating local immune responses and angiogenesis during human pregnancy.     

Ki67和Caspase-3在外阴癌变中的表达及临床意义

目的 检测及探讨Ki67和Caspase-3在外阴癌变中的作用.方法 选取1996年1月至2006年8月在中国医科大学附属第一医院外阴鳞癌(VSCC)30例,并收集其临床病理特征;外阴上皮内瘤变(VIN)30例;外阴上皮内非瘤样病变(NNED)30例;正常外阴皮肤10例.采用鼠抗人Ki67单克隆抗体及兔抗人Caspase-3多克隆抗体以SP免疫组化法进行研究.结果 Ki67在外阴鳞癌中高表达(阳性率83.3%),在VIN及NNED中表达下降,在外阴正常皮肤中低表达.Caspase-3 在外阴鳞癌中低表达(阳性率53.3%),在VIN及NNED及外阴正常皮肤中表达增加.Caspase-3的表达随外阴鳞癌的分化程度降低而降低(P＜0.05).Caspase-3蛋白和Ki67蛋白在30例外阴鳞癌中的表达呈负相关(P＜0.05).结论 细胞增殖标记抗原Ki67的表达阳性率增高与外阴癌的发生密切相关.细胞凋亡相关蛋白Caspase-3参与了外阴癌的发生过程,并且可能作为评价外阴癌侵袭性的一个指标.     

Expression of epidermal growth factor receptor and c-erbB-2 oncoprotein in trophoblast populations of placenta accreta

OBJECTIVE: The purpose of this study was to investigate the expression of epidermal growth factor receptor and c-erbB-2 oncoprotein in trophoblast populations of placenta accreta. STUDY DESIGN: Paraffin sections of 43 placental specimens with (cases) and 43 without (controls) placenta accreta were studied immunohistochemically for epidermal growth factor receptor and c-erbB-2 expression in the syncytiotrophoblast, villous cytotrophoblast, and extravillous cytotrophoblast. Epidermal growth factor receptor and c-erbB-2 protein levels were also performed by Western blot analysis. Controls were matched for gestational age in this case-control study. RESULTS: The percentage of strong/intermediate immunoreactivity of epidermal growth factor receptor in the syncytiotrophoblast was significantly higher in cases (98%) than controls (79%; odds ratio,11.1; 95% CI, 1.3-92.0; P = .03), although strong/intermediate immunoreactivity of c-erbB-2 in the syncytiotrophoblast was significantly lower in cases (35%) than controls (81%; odds ratio, 0.1; 95% CI, 0.1-0.3; P < .001). Epidermal growth factor receptor and c-erbB-2 expression in the villous and extravillous cytotrophoblastic cells were not significantly different between controls and cases ( P > .05). Most immunoreactive bands on Western blots were consistent with the trends of immunohistochemical findings. CONCLUSION: The development of placenta accreta is related closely to the differential expression of epidermal growth factor receptor and c-erbB-2 in the syncytiotrophoblast.     

Immunostaining of transferrin and transferrin receptor in human seminiferous tubules

Transferrin (TF) and transferrin receptor (TFr) were studied in human testicular biopsy specimens with the use of immunostaining techniques. A polyclonal antibody to human TF (obtained in goat), a murine monoclonal antibody (B3/25) to human TFr, and antisera antigoat IgG and antimouse IgG, both labeled with peroxidase, were used. In seminiferous tubules of subjects with normal spermatogenesis, TF was found mainly in Sertoli cells and, in lesser amounts (probably related to the presence of receptor-TF complexes), in spermatocytes and early spermatids. TFrs were found only in spermatocytes and early spermatids. In patients with spermatogenetic disorders, TF was always found in Sertoli cells, whereas TFrs were found in spermatocytes only when they were present. These results seem to demonstrate that in human seminiferous tubules, Sertoli cells are devoted to the production and/or storage of TF, whereas spermatocytes and early spermatids use TF.     

Human amniotic fluid transferrin stimulates progesterone production by human trophoblast cells in vitro

OBJECTIVE: During pregnancy transferrin plays a key role as an iron transport protein to serve the increased fetal demands of iron. Transferrin is also present in relatively high concentrations in amniotic fluid [6], showing a different glycosylation compared with serum transferrin. The biological function of human amniotic fluid transferrin (hAFT) is still unknown. In addition trophoblast cells also synthesise transferrin. Transferrin synthesised by the trophoblast shows a special glycosylation. We found identical carbohydrate structure of hAFT and trophoblast transferrin. We investigated the influence of hAFT on the progesterone-, cortisol- and hCG-release of trophoblasts in culture compared with the influence of human holo- and apo-serum transferrin on the release of these hormones. MATERIAL AND METHODS: Cytotrophoblast cells were prepared from human term placentae by standard trypsin-DNAse dispersion of villous tissue followed by a percoll gradient centrifugation step. When placed in culture, the trophoblasts were incubated with varying concentrations (50-300 micrograms/ml) of human amniotic fluid- and serum-transferrin. Unstimulated cells of each placenta used as controls. Culture supernatants were assayed for progesterone, hCG and cortisol by enzyme-immunometric methods. RESULTS: Our results show, that the release of progesterone increased in hAFT-treated cell cultures compared to untreated cell cultures. Holo- and apo-serumtransferrin did not show any effect on the progesterone release by trophoblast cells in vitro. Neither hAFT nor holo- and apo-serum transferrin had any effect on the cortisol- and hCG-release in vitro. CONCLUSIONS: Progesterone is a marker for differentiation of trophoblasts in syncytiotrophoblasts. Only hAFT stimulates the progesterone production. We suggest, that hAFT can modulate the endocrine function of trophoblast cells in culture by regulating progesterone production.     

表皮生长因子受体在子宫内膜、早孕蜕膜及滋养细胞中的表达

目的了解表皮生长因子受体（ＥＧＦＲ）在子宫内膜细胞分化及发育中的作用。方法采用免疫组织化学及逆转录聚合酶链反应（ＲＴＰＣＲ）技术测定５８例正常子宫内膜（３２例增生期,２６例分泌期）与２６例早孕蜕膜。结果ＥＧＦＲ存在于正常子宫内膜、早孕蜕膜腺体及间质细胞的细胞膜、核膜及胞浆内,分布均匀。ＥＧＦＲ还位于早孕蜕膜腺体及间质细胞核内。正常子宫内膜ＥＧＦＲ的表达,腺体部分高于间质部分（Ｐ＜０．０５）,ＥＧＦＲ在增生期及分泌期子宫内膜腺体的表达差异无显著性（Ｐ＞０．０５）,但ＥＧＦＲ在早孕蜕膜组织中的表达明显高于增生期及分泌期（Ｐ＜０．０５）。ＥＧＦＲ在间质细胞的表达,早孕蜕膜高于分泌期内膜,而增生期内膜则表达最低（Ｐ＜０．０５）。ＥＧＦＲｍＲＮＡ的表达从弱到强依次为增生期、分泌期、蜕膜、滋养细胞,增生期与分泌期比较,差异无显著性（Ｐ＞０．０５）,早孕蜕膜较分泌期及增生期明显增加（Ｐ＜０．０５）,滋养细胞ＥＧＦＲｍＲＮＡ的表达明显高于增生期、分泌期及早孕蜕膜（Ｐ＜０．０５）。结论ＥＧＦＲ存在于各期子宫内膜中,其表达在正常月经周期中无明显变化,但在早孕蜕膜、滋养细胞中的表达明显高于增生期及分泌期内膜     

Antigen expression by trophoblast populations in the human placenta and their possible immunobiological relevance

Antigen expression by villous and extravillous human trophoblast populations at discrete anatomical sites has been reviewed. The various different antigenic phenotypes have been highlighted using a panel of monoclonal antibodies reactive with characteristic trophoblast membrane antigens, a trophoblast-leucocyte common antigen, class I MHC antigens, epithelial cell cytokeratin and epithelial membrane markers. This approach has allowed three separate fetal trophoblast populations to be identified within term amniochorionic membranes, and also has facilitated further definition of trophoblast populations in maternal uterine tissues. Furthermore, antigenic alterations have been noted in the maternal uterine gland epithelium in pregnancy leading to the expression of a trophoblastic phenotype, thereby suggesting a mechanism of extrinsic regulation of gene expression in these tissues. The possible involvement in the immunoregulatory control of maternal responses in pregnancy of MHC-linked gene products expressed by trophoblast has been discussed.     

Survivin、Ki67及雌孕激素受体在子宫内膜息肉中的表达及临床意义

目的 探讨Survivin、Ki67、雌激素受体(ER)、孕激素受体(PR)在绝经前后妇女子宫内膜息肉中表达的相关性及绝经前后子宫内膜息肉的发生机制.方法 选取2000-2005年首都医科大学附属北京天坛医院经病理证实的50例绝经前后妇女子宫内膜息肉组织(绝经前息肉组27例,绝经后息肉组23例)及同期30例正常子宫内膜组织(绝经前对照组20例,绝经后对照组10例),应用免疫组化SP法进行Survivin、Ki67、ER、PR表达的检测目的(1)绝经前:Survivin、Ki67、ER在息肉腺体中的表达高于对照组(分别为98.96±5.68时83.67±20.25.32.46±35.95对12.43±25.88,85.59±27.08对73.46±32.03,P均<0.05).ER、PR在息肉组间质中的表达高于对照组(分别为58.76±33.10时50.31±24.43,73.05±25.42对61.30±30.49,P均<0.05).(2)绝经后:ER、PR、Ki67、Survivin在息肉腺体中的表达均高于对照组(97.42±7.19对49.06±26.41,93.25±25.14时56.67±29.68,30.70±37.95对0.50±0.89,100.00±0.00对0.02±0.01,P均<0.05);在息肉问质PR表达与绝经后对照组差异无统计学意义(43.32±31.19对50.00士23.14,P>0.05).结论 (1)子宫内膜息肉的发生与局部ER、PR的分布失衡及细胞增殖亢进和凋亡抑制有关.(2)绝经前息肉可能以子宫内膜局部细胞增殖亢进、凋亡抑制为主要发生机制.绝经后息内可能以子宫内膜局部ER、PR分布失衡为主要发病机制.     

Expression of DAB2IP in human trophoblast and its role in trophoblast invasion

Objective: DAB2IP is a growth inhibitor present in many types of cancer cells and is associated with epigenetic regulations controlling tumor development. The primary objective of this study is to determine whether DAB2IP participates in the invasion and migration of trophoblasts during placental development.

Methods: The expressions of DAB2IP in human placentas (10 villi, 18 term placentas and 20 pre-eclampsia placentas) were determined by immunohistochemistry, Western blotting and quantitative RT-PCR. HTR8/SVneo cells were treated with hypoxia–reoxygenation (H/R) to test how DAB2IP expression would affect the invasion and migration of trophoblasts. JEG-3 andHTR8/SVneo cells were treated with 5-aza-2-deoxycytidine (5-aza-dC) to study the role of DAB2IP promoter methylation in trophoblasts.

Results: DAB2IP was strongly expressed in human villi and extravillous trophoblasts as well as in HTR8/SVneo cells, but not in pre-eclampsia placentas. DAB2IP expression increased after H/R treatment, but the invasive and migratory abilities of trophoblasts were reduced. DAB2IP expression in JEG-3 cells also increased after treatment with 5-aza-dC.

Conclusions: These findings strongly suggest that DAB2IP is an important negative regulator at the maternal–fetal interface during early pregnancy. Excessive oxidative stress can increase DAB2IP expression in trophoblasts. The mechanism of DNA methylation may involve in its function during the development of pathologic pregnancy.     

Hormonal and basement membrane markers for immunoidentification of cultured human trophoblast cells

Improvement of human chorionic villi cells in vitro culture has been obtained by supplementing the medium with 30% human fetal cord serum, instead of fetal calf serum. Expression of human chorionic gonadotropin, estrogen and progesterone receptors, laminin, laminin receptors, and type IV collagen has been studied on first subculture passages (4-7 weeks) by immunoperoxidase method. A minority of the cultured cells were positive for estrogen receptors, the majority were positive for progesterone receptors, while all cells were negative for human chorionic gonadotropin. Cultured cells showed variable positive immunostaining for basement membrane markers like laminin, and type IV collagen, and for laminin receptors. Detection of both progesterone receptors and laminin, or type IV collagen, excluded fibroblast contamination and could then be useful for quick identification of cultured trophoblast cells.     

Expression of endothelial nitric oxide synthase by extravillous trophoblast cells in the human placenta

Previous reports have documented the expression of endothelial nitric oxide synthase (eNOS) expression by the syncytiotrophoblast layer of the villus in the human placenta. In contrast, the underlying villous cytotrophoblast cells do not express the enzyme. Because extravillous cytotrophoblasts have not been as extensively investigated, our objective was to test whether these cells express eNOS. Using both a mouse monoclonal and a rabbit polyclonal antibody, we demonstrated immunoreactive eNOS in trophoblast cell columns emanating from anchoring villi in second trimester placentae. Cytokeratin positive trophoblast cells lying beneath remnant anchoring villi, lining decidual blood vessels and scattered throughout the basal plate of normal term and pre-eclamptic placentae also expressed immunoreactive eNOS. By Western analysis, the monoclonal and polyclonal antibodies were shown to be absolutely and relatively specific for eNOS, respectively. The finding of immunoreactive eNOS expression by extravillous trophoblast cells was substantiated by in situ hybridization. Using riboprobes generated from a bovine eNOS cDNA, we demonstrated specific hybridization in the endothelium of blood vessels in the umbilical cord, thus validating the in situ hybridization methodology, as well as specific hybridization in the extravillous trophoblast cells of the basal plate in normal term placenta. In conclusion, several different populations of extravillous trophoblast cells in the basal plate of the human placenta express eNOS.     

miR-219a suppresses human trophoblast cell invasion and proliferation by targeting vascular endothelial growth factor receptor 2 (VEGFR2)

ObjectiveVascular endothelial growth factor (VEGF) plays a critical role in regulating trophoblast cell invasion and proliferation, involved in a variety of pregnancy complications, such as spontaneous abortion and pre-eclampsia. Numerous studies have revealed that microRNAs (miRNAs) are participated in a series of molecular processes that regulate cell function, such as cell invasion, proliferation, and apoptosis. Vascular endothelial growth factor receptor 2 (VEGFR2), a receptor of VEGF, has been shown to be involved in trophoblast function. However, the relation between miRNA and VEGFR2 and their role in trophoblast function remain to be elucidated.MethodsThe effect of miR-219a on the trophoblast function has been explored using luciferase reporter, transwell, qRT-PCR, western blot, bromodeoxyuridine (BrdU), ELISA, immunofluorescent staining, and tube formation assays.ResultsIn the current study, we observed that through targeted inhibition of VEGFR2 expression by miR-219a, the function of VEGFR2 as well as the downstream PI3K/AKT/NF-κB signaling pathway were suppressed, leading to suppression of trophoblastic proliferation and invasion. Moreover, upregulation of VEGFR2 restored the miR-219a–inhibited cell proliferation, invasion, and tube formation.ConclusionsThese results revealed that miR-219a played crucial roles in negatively regulating trophoblastic proliferation and invasion by suppression of the PI3K/AKT/NF-κB signaling pathway by targeting VEGFR2, therefore serving as a potential treatment method for the complications of pregnancy caused by trophoblastic dysregulation.