title: Effect of cell-penetrating peptide-conjugated estrogen-related receptor β on the development of mouse embryos cultured in vitro.
abstract: OBJECTIVE
  Estrogen related receptor β (Esrrb) is a member of the orphan nuclear receptors and may regulate the expression of pluripotency-related genes, such as Oct4 and Nanog. Therefore, in the present study, we have developed a method for delivering exogenous ESRRB recombinant protein into embryos by using cell-penetrating peptide (CPP) conjugation and have analyzed their effect on embryonic development.
  
  
  METHODS
  Mouse oocytes and embryos were obtained from superovulated mice. The expression of Oct4 mRNA and the cell number of inner cell mass (ICM) in the in vitro-derived and in vivo-derived blastocysts were first analyzed by real time-reverse transcription-polymerase chain reaction and differential staining. Then 8-cell embryos were cultured in KSOM media with or without 2 µg/mL CPP-ESRRB protein for 24 to 48 hours, followed by checking their integration into embryos during in vitro culture by Western blot and immunocytochemistry.
  
  
  RESULTS
  Expression of Oct4 and the cell number of ICM were lower in the in vitro-derived blastocysts than in the in vivo-derived ones (p<0.05). In the blastocysts derived from the CPP-ESRRB-treated group, expression of Oct4 was greater than in the non-treated groups (p<0.05). Although no difference in embryonic development was observed between the treated and non-treated groups, the cell number of ICM was greater in the CPP-ESRRB-treated group.
  
  
  CONCLUSIONS
  Treatment of CPP-ESRRB during cultivation could increase embryos' expression of Oct4 and the formation rate of the ICM in the blastocyst. Additionally, an exogenous delivery system of CPP-conjugated protein would be a useful tool for improving embryo culture systems.
authors.affiliation: Department of Biomedical Science, College of Life Science, CHA University, Seoul, Korea.
authors.forename: Ning Jie
authors.initials: NJ
authors.lastname: Yang
authors.affiliation: Department of Biomedical Science, College of Life Science, CHA University, Seoul, Korea.
authors.forename: Dong-Won
authors.initials: DW
authors.lastname: Seol
authors.affiliation: Department of Biomedical Science, College of Life Science, CHA University, Seoul, Korea.
authors.forename: Junghyun
authors.initials: J
authors.lastname: Jo
authors.affiliation: Department of Biomedical Science, College of Life Science, CHA University, Seoul, Korea.
authors.forename: Hyun Mee
authors.initials: HM
authors.lastname: Jang
authors.affiliation: Department of Biomedical Science, College of Life Science, CHA University, Seoul, Korea. ; Fertility Center of CHA Gangnam Medical Center, CHA University, Seoul, Korea.
authors.forename: Sook-Young
authors.initials: SY
authors.lastname: Yoon
authors.affiliation: Department of Biomedical Science, College of Life Science, CHA University, Seoul, Korea. ; Fertility Center of CHA Gangnam Medical Center, CHA University, Seoul, Korea.
authors.forename: Dong Ryul
authors.initials: DR
authors.lastname: Lee
keywords: Cell-penetrating peptide; Estrogen-related receptor β; In vitro culture; Mouse embryo; Oct4