Comparative evaluation of different in vitro systems that stimulate germ cell differentiation in human embryonic stem cells.

OBJECTIVE

To explore several culture systems that may prove efficient in driving human embryonic stem cells (hESCs) toward a germ cell lineage.

DESIGN

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.

SETTING

Department of Obstetrics and Gynecology, National University of Singapore Research Laboratories, Singapore.

PATIENT(S): None.

INTERVENTION(S): None.

MAIN OUTCOME MEASURE(S): None.

RESULT(S): 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.

CONCLUSION(S): 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.