Generation of human induced trophoblast stem cells

SUMMARY Human trophoblast stem cells (hTSC) derived from blastocysts and first-trimester cytotrophoblasts offer an unprecedented opportunity to study the human placenta. However, access to human embryos and first trimester placentas is limited thus preventing the establishment of hTSC from a variety of genetic backgrounds associated with placental disorders. In the present study, we show that hTSC can be generated from numerous genetic backgrounds using post-natal cells via two alternative methods: (I) somatic cell reprogramming of adult fibroblasts using the Yamanaka factors, and (II) cell fate conversion of naive and extended pluripotent stem cells. The resulted induced and converted hTSC (hiTSC/hcTSC) recapitulated hallmarks of hTSC including long-term self-renewal, expression of specific transcription factors, transcriptome-side signature, and the potential to differentiate into syncytiotrophoblast and extravillous trophoblast cells. We also clarified the developmental stage of hTSC and show that these cells resemble post-implantation NR2F2+ cytotrophoblasts (day 8-10). Altogether, hTSC lines of diverse genetics origins open the possibility to model both placental development and diseases in a dish. Highlights Reprogramming of human somatic cells to induced hTSC with OSKM Conversion of naive and extended hPSC to hTSC Genetic diversity of hTSC lines Developmental matching of hTSC in the peri-implantation human embryo