RESUMO
Abnormal trophoblast function is associated with human fetal growth restriction (FGR). Targeted disruption of homeobox gene transforming growth ß-induced factor (TGIF-1) results in placental dysfunction in the mouse. The role of human TGIF-1 in placental cell function is unknown. The aims of this study were to determine the expression of TGIF-1 in human idiopathic FGR-affected placentae compared with gestation-matched controls (GMC), to elucidate the functional role of TGIF-1 in trophoblasts and to identify its downstream targets. Real-time PCR and immunoblotting revealed that TGIF-1 mRNA and protein expression was significantly increased in FGR-affected placentae compared with GMC (n = 25 in each group P < 0.05). Immunoreactive TGIF-1 was localized to the villous cytotrophoblasts, syncytiotrophoblast, microvascular endothelial cells and in scattered stromal cells in both FGR and GMC. TGIF-1 inactivation in BeWo cells using two independent siRNA resulted in significantly decreased mRNA and protein of trophoblast differentiation markers, human chorionic gonadotrophin (CGB/hCG), syncytin and 3ß-hydroxysteroid dehydrogenase/3ß-honest significant difference expression. Our data demonstrate that homeobox gene TGIF-1 is a potential up-stream regulator of trophoblast differentiation and the altered TGIF-1 expression may contribute to aberrant villous trophoblast differentiation in FGR.
Assuntos
Retardo do Crescimento Fetal/metabolismo , Proteínas de Homeodomínio/metabolismo , Proteínas Repressoras/metabolismo , Trofoblastos/citologia , Trofoblastos/metabolismo , 3-Hidroxiesteroide Desidrogenases/genética , 3-Hidroxiesteroide Desidrogenases/metabolismo , Adulto , Animais , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Gonadotropina Coriônica/genética , Gonadotropina Coriônica/metabolismo , Feminino , Retardo do Crescimento Fetal/genética , Produtos do Gene env/genética , Produtos do Gene env/metabolismo , Proteínas de Homeodomínio/genética , Humanos , Camundongos , Gravidez , Proteínas da Gravidez/genética , Proteínas da Gravidez/metabolismo , Proteínas Repressoras/genéticaRESUMO
Human idiopathic foetal growth restriction (FGR) is frequently associated with placental insufficiency. In our previous studies, we have reported the isolation and characterisation of the homeobox gene Distal-less 3 (DLX3) in the human placenta. In this study, we have investigated the level of DLX3 expression in idiopathic FGR-affected placentae and determined its functional role in villous trophoblast differentiation. FGR-affected placentae (n = 25) were collected based on well-defined clinical criteria and matched for gestation with control uncomplicated pregnancies (n = 25). Real-time polymerase chain reaction and immunoblotting showed increased DLX3 mRNA and protein expression in FGR-affected placentae compared with gestation-matched controls. Qualitative immunohistochemistry revealed DLX3 localisation in the syncytiotrophoblast, cytotrophoblasts and endothelial cells surrounding the foetal capillaries in both FGR-affected and control placentae. Down-regulation of DLX3 in primary villous trophoblast cells and a trophoblast-derived cell line showed decreased expression of differentiation markers, 3ßHSD, ßhCG and syncytin. Therefore, we conclude that increased DLX3 expression in FGR may contribute to trophoblast dysfunction observed in FGR.
