Epigenetic and non-epigenetic regulation of syncytin-1 expression in human placenta and cancer tissues.
Syncytin-1 is a human endogenous retroviral envelope gene (HERVW1) product specifically expressed in placental trophoblasts. By mediating the formation of syncytiotrophoblasts through cell-cell fusion, syncytin-1 plays a critical role for the placental barrier, endocrine and exchange functions. During pregnancy, syncytin-1 expression is dynamically regulated by various pathophysiological factors and pathways. This review summarizes and examines published data on epigenetic and non-epigenetic regulation of syncytin-1 gene expression, with a focus on the changes of syncytin-1 DNA methylation and expression in placental trophoblasts under preeclamptic and hypoxic conditions. The functions of syncytiotrophoblasts, the fusogenic and non-fusogenic activities of syncytin-1, and aberrant activation of syncytin-1 expression in cancer cells are also discussed. New findings on the epigenetic regulation of syncytin-1 in placentas from monozygotic/dichorionic discordant twins are analyzed. The close correlation among changes of DNMTs expression, syncytin-1 gene methylation, and syncytin-1 mRNA levels, in placentas associated with discordant fetal growth indicated a dynamic nature of syncytin-1 regulation.
The Second Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi 710004, China; Department of Biological Science, Mercer University School of Medicine, Savannah, GA 31404, USA.
Qiang
Q
Huang
Department of Department of Histology and Embryology, Shantou University Medical College, Guandong, China.
Haibin
H
Chen
Department of Biological Science, Mercer University School of Medicine, Savannah, GA 31404, USA; Department of Obstetrics and Gynecology, Mayo Medical College, Mayo Clinic and Mayo Foundation, 55902, USA.
Jinping
J
Li
Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA 31404, USA.
Matthew
M
Oliver
Department of Biological Science, Mercer University School of Medicine, Savannah, GA 31404, USA.
Xiaoling
X
Ma
Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA 31404, USA.
David
D
Byck
The Second Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi 710004, China. Electronic address: ygao@mail.xjtu.edu.cn.
Ya
Y
Gao
Department of Biological Science, Mercer University School of Medicine, Savannah, GA 31404, USA; Department of Obstetrics and Gynecology, Mayo Medical College, Mayo Clinic and Mayo Foundation, 55902, USA; Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, GA 31404, USA. Electronic address: jiang_@mercer.edu.
Shi-Wen
SW
Jiang
D002454:Cell Differentiation / Q000235:genetics; D002459:Cell Fusion; D015687:Cell Hypoxia; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D019175:DNA Methylation; D004268:DNA-Binding Proteins; D020077:Endogenous Retroviruses; D044127:Epigenesis, Genetic / Q000235:genetics; D005260:Female; D005317:Fetal Growth Retardation / Q000473:pathology; D015686:Gene Products, env / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D009369:Neoplasms / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D010920:Placenta / Q000378:metabolism*; D011225:Pre-Eclampsia / Q000473:pathology; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D014157:Transcription Factors / Q000378:metabolism; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism*; D014430:Twins, Monozygotic / Q000235:genetics
D004268:DNA-Binding Proteins; C491089:GCM1 protein, human; D015686:Gene Products, env; D009687:Nuclear Proteins; D011257:Pregnancy Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; C405335:syncytin; D017868:Cyclic AMP-Dependent Protein Kinases
DNA Methylation; HERVW1, Preeclampsia; Non-fusogenic; Synctyine-1; Syncytiotrophoblast; Trophoblast