Chimerization of human ESC-derived extraembryonic cells with the mouse blastocyst

Area of Science:

• Developmental Biology
• Stem Cell Biology
• Reproductive Biology

Background:

• Human embryonic stem cells (hESCs) can differentiate into extraembryonic (ExE) cells in vitro using specific growth factors and inhibitors.
• Ethical limitations restrict in vivo studies of human ExE cell developmental potential using human embryos.

Purpose of the Study:

• To investigate the in vivo developmental potential of hESC-derived ExE cells.
• To establish novel methods for studying ExE cell differentiation and contribution to embryonic and extraembryonic tissues.

Main Methods:

• hESCs were differentiated into ExE cells using BMP4, A83-01, and PD173074 (BAP).
• ExE cells were transplanted into mouse uteri and blastocysts.
• Chimeric embryos were analyzed for human cell contribution and marker expression at E14.

Main Results:

• hESC-derived ExE cells expressed markers for trophoblasts and amniotic cells.
• Intra-uterine transplantation showed ExE cell contribution to the mouse placenta.
• Intra-blastocyst injection resulted in ExE cell chimerism, contributing to placenta and embryo cartilage (SOX9+).
• MSX2 deletion restricted ExE cell contribution to the placenta.

Conclusions:

• hESC-derived ExE cells can chimerize with mouse blastocysts, contributing to both placental and embryonic tissues.
• ExE cells exhibit heterogeneous developmental potential, including mesodermal differentiation.
• Intra-uterine and intra-blastocyst injections are effective methods for studying ExE cell developmental potential.