title: Comparative evaluation of different in vitro systems that stimulate germ cell differentiation in human embryonic stem cells.
abstract: OBJECTIVE
  To explore several culture systems that may prove efficient in driving human embryonic stem cells (hESCs) toward a germ cell lineage.
  
  
  METHODS
  Embryoid bodies (EBs) derived from a female hESC line [HES-3 (XX)] and male hESC line [HES-4 (XY)] were cultured in six different culture conditions: [1] mitotically inactivated porcine ovarian fibroblasts (POF), [2] 100% conditioned medium from POF, [3] 50% conditioned medium from POF, [4] forskolin, [5] trans-retinoic acid (RA), and [6] forskolin and RA.
  
  
  METHODS
  Department of Obstetrics and Gynecology, National University of Singapore Research Laboratories, Singapore.
  
  
  METHODS
  None.
  
  
  METHODS
  None.
  
  
  METHODS
  None.
  
  
  RESULTS
  Expression data for both HES-3 and HES-4 differentiating cultures strongly indicated that inactivated POFs encouraged differentiation of hESC EBs into a germ cell lineage. VASA and other germ cell markers were found to be elevated in all six culture conditions.
  
  
  CONCLUSIONS
  Overall, POFs proved to be the best system for initiating germ cell differentiation, as shown by increases in the expression of several germ cell marker genes in EBs that were cocultured with POFs.
authors.affiliation: Department of Obstetrics and Gynecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119074.
authors.forename: Mark
authors.initials: M
authors.lastname: Richards
authors.forename: Chui-Yee
authors.initials: CY
authors.lastname: Fong
authors.forename: Ariff
authors.initials: A
authors.lastname: Bongso
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D018929:Cell Culture Techniques / Q000379:methods*; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D019070:Cell Lineage / Q000187:drug effects / Q000502:physiology; D018920:Coculture Techniques / Q000379:methods; D005576:Colforsin / Q000494:pharmacology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000187:drug effects; D005260:Female; D005347:Fibroblasts / Q000166:cytology; D005854:Germ Cells / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D008297:Male; D010053:Ovary / Q000166:cytology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D015415:Biomarkers; D017077:Culture Media, Conditioned; D005576:Colforsin; D014212:Tretinoin; C498288:DDX4 protein, human; D053487:DEAD-box RNA Helicases