Distribution of human endogenous retrovirus type W receptor in normal human villous placenta

BACKGROUND: The fusion of trophoblast cells into the villous syncytiotrophoblast is crucial for appropriate placental function and fetal development. Fusion occurs following the interaction of syncytin-1, an envelope protein of the endogenous retrovirus HERV-W, and the RD114/mammalian type D retrovirus receptor (RDR/ASCT2) on adjacent cell membranes. This process must be tightly regulated in order to maintain the proliferative pool of cytotrophoblast cells as well as the function of the syncytia. AIM: We sought to investigate whether syncytial fusion of placental cytotrophoblast cells may be regulated via modulation of RDR/ASCT2 expression. METHODS: Expression of RDR/ASCT2 in term and first trimester villous placenta was assessed along with a number of molecular markers using immunofluorescent staining. In a complementary approach, Western blotting was used to investigate RDR/ASCT2 expression in a panel of choriocarcinoma cell lines before and after stimulation of fusion. RESULTS: Villous placental RDR/ASCT2 expression was found to be restricted to the cytotrophoblast compartment, being largely absent in the syncytiotrophoblast. Local variations in RDR/ASCT2 expression were not associated with the proliferative status of cytotrophoblast cells. RDR/ASCT2 expression was also shown to be down-regulated in BeWo choriocarcinoma cells after stimulation of syncytial fusion. CONCLUSION: This first report of the localisation and distribution of RDR/ASCT2 in human placental villi suggests that the fusion of placental trophoblast cells is not regulated by local or temporal variations of RDR/ASCT2 expression in villous cytotrophoblast cells.     

腺病毒载体介导肝细胞生长因子基因对血管内皮细胞的作用

目的：研究腺病毒载体介导肝细胞生长因子（HGF）基因感染血管内皮细胞后在正常供氧、缺氧及缺氧后复氧的情况下细胞的凋亡情况。方法：将分离、培养的内皮细胞分为3组，分别给予M199（对照组）、HGF（HGF组）和HGF基因腺病毒载体（Ad-HGF组），分别在正常供氧、缺氧及缺氧后复氧3种情况下观察细胞的凋亡情况。结果：Ad-HGF组及HGF组细胞凋亡数均低于对照组（P〈0．01），Ad-HGF组与HGF组细胞凋亡数差异无显著性意义。结论：腺病毒载体介导HGF基因感染内皮细胞后能在缺氧情况下有效地阻止细胞凋亡。     

肝细胞特异性HuR基因敲除小鼠模型的表型研究

目的 探讨肝细胞特异性敲除HuR基因对小鼠肝脏功能的影响。方法 从美国Jackson实验室引进LoxP标记的人抗原R（human antigen R,HuR）基因小鼠（HuR^fl/fl）和Alb-Cre转基因小鼠。杂交后,经数代选育配种,建立肝细胞特异性HuR基因敲除小鼠（HuR^LKO）模型。PCR技术鉴别小鼠基因型,蛋白免疫印迹和免疫荧光实验检验小鼠肝脏的HuR表达水平,同时HE染色观察肝脏结构变化。高脂喂养HuR^fl/fl/Alb-Cre和HuR^fl/fl两组小鼠,观察小鼠体重、肝重和肝体比变化,提取血清检测肝脏损伤和脂肪代谢相关指标。结果 PCR成功检测筛选子代小鼠基因型,包括HuR^fl/fl/Alb-Cre和HuR^fl/fl小鼠。蛋白免疫印迹实验和免疫荧光实验证明小鼠肝细胞特异性HuR基因敲除成功。HE染色结果提示HuR^LKO小鼠的肝细胞出现变性水肿、局部坏死。高脂喂养实验提示两组小鼠在肝重、肝体比、AST、ALT、HDL-C、血糖上的差异具有统计学意义（P＜0.05）,但在体重、TG、LDL-C的差异没有统计学意义（P＞0.05）。结论 HuR基因是维持小鼠肝细胞功能的必要基因,Cre-LoxP技术可成功构建HuR^LKO小鼠模型,且特异性高,表型明显,为研究HuR在肝脏各项疾病的发生发展中所扮演的角色,提供了一个很好的疾病模型。     

Immunohistochemical study for the origin of ductular reaction in chronic liver disease

The appearance of proliferating bile ductular structures, which is called the “atypical ductular reaction” is frequently observed in various chronic liver diseases associated. However, the origin of these increased bile ductules has been a matter of controversy. In this study, we investigated the origin of ductular cells as an aspect of relation between epithelial to mesenchymal transition (EMT) and epithelial members of liver parenchyme, such as hepatocyte and cholangiocyte by immunohistochemical staining of human liver. Thirteen specimens of surgically resected liver with biliary cirrhosis were selected. Three sets of double immunohistochemical stains were done; Hep-Par 1 - cytokeratin 19 (CK19), Hep-Par 1 - α-sm ooth mus cle actin (α-SMA) and CK19 - α-SMA. As a result, we investigated the dual expression of the markers of hepatocyte and cholangiocyte in the same cell; in ductular cell and surrounding hepatocyte. However, there seems to be no dual expression of markers for EMT with epithelial markers. This study suggests a possibility of phenotypic change of mature hepatocyte into cholangiocyte. Future studies will be necessary to determine the role that proliferating cholangiocytes play in the pathogenesis of biliary fibrosis and how cholangiocytes interact with other cell types of the liver such as hepatic stellate cells or Kupffer cells.