title: Retinoic acid improve germ cell differentiation from human embryonic stem cells.
abstract: BACKGROUND
  Creation of artificial gametes may provide a universal solution for these patients with no gametes. Stem cell technology may provide a way to obtain fully functional gametes. Retinoic acid (RA) can initiate meiosis. Several studies have demonstrated that RA can promote sperm cells differentiation from mouse embryonic stem cells (mESCs) and other cells from human embryonic stem cells (hESCs).
  
  
  OBJECTIVE
  We sought to determine whether RA could promote differentiation of germ cells from hESCs.
  
  
  METHODS
  hESCs were differentiated as embryoid bodies (EBs) in suspension with all-trans RA (atRA) or without atRA for 0, 1, 3, 5 and 7 days, and then the expression of VASA, SCP3, GDF9 and TEKT1 were compared by real-time PCR. The statistical differences were evaluated by one way ANOVA.
  
  
  RESULTS
  The expression of germ cell-specific markers including the gonocyte marker VASA, the meiotic marker SCP3, and post meiotic markers, GDF9 and TEKT1, all increased in the presence and absence of RA as EB differentiation progressed. In addition, the expression of these markers increased an average of 9.3, 6.9, 7.2 and 11.8 fold respectively in the presence of RA, compared to the absence of RA, over 5 days differentiation.
  
  
  CONCLUSIONS
  Our results indicate that hESCs may have the potential to differentiate to primordial germ cells (PGCs) and early gametes. RA can improve germ cells differentiation from hESCs.
authors.affiliation: Reproductive Medicine Center, Yantai Yuhuangding Hospital, Yantai 264000, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Xuemei
authors.affiliation: Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Jing
authors.affiliation: Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Bei
authors.affiliation: Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Hu
authors.initials: H
authors.lastname: Juan
authors.affiliation: Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Ren
authors.initials: R
authors.lastname: Xinling
authors.affiliation: Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Qun
authors.affiliation: Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Zhu
authors.initials: Z
authors.lastname: Guijin
keywords: Cell Differentiation; Embryonic Stem Cells; Germ cells; Retinoic acid