Study of Direct Differentiation of hESCs to Thymic Epithelial Cells by Overexpressing Transcription Factor FOXN1

Abstract: By overexpressing transcription factor FOXN1 (forkhead box protein N1) in human embryonic stem cells (hESCs)， observing cell morphological changes and analyzing gene expression of the hESC-derived TECs， we successfully generated thymic epithelial cells (TECs). We knocked in FOXN1-mCherry reporter element in hESCs by TALEN-mediated homologous recombination. A Tet-on inducible lentiviral system was used to overexpress FOXN1 in hESCs. The results showed that after induction， hESCs colonies gradually became flat with enlargement of cells， which was consonant with typical morphology of TECs. RT-PCR results indicated that mRNA level of TEC specific genes including TBX1， HOXA3， EYA1， K5 and K8， as well as endogenous FOXN1 were significantly upregulated. The increase of TEC marker gene expression accumulated over time and reach the top by day 12. Moreover， the expression of K5 and K8 were detected in the hESC-derived TECs by immunostaining. About 19% and 45% of differentiated cells expressed K5 and K8， respectively. These results demonstrated that hESCs could be directly differentiated into TECs by overexpressing transcription factor FOXN1.

CSTR: 32200.14.cjcb.2015.12.0004