Abstract

Mid-gestation c-KIT⁺ amniotic fluid stem cells (AFSC) have an intermediate phenotype between embryonic and adult stem cells and are easy to reprogram to pluripotency. We previously showed that 1^st trimester AFSC can be reprogrammed to functional pluripotency in a transgene-free approach. Despite both parental populations sharing a common phenotype, expressing CD29, CD44, CD73, CD90, CD105, SSEA4 and OCT4, 2^nd trimester AFSC, contrary to 1^st trimester cells, do not express NANOG, SSEA3, TRA-1-60 and TRA-1-81, and have slower growth kinetics. Here, we used the Illumina Beadstudio microarray platform to analyse the transcriptome of 1^st and 2^nd trimester AFSC and show a unique 1^st trimester AFSC-specific gene expression signature consisting of 366 genes and a larger set of 603 genes common with hESC compared to 496 genes overlapping between 2^nd trimester AFSC and hESC. We conclude that both populations are related but distinct to each other as well as to hESC.

Keywords: Amniotic fluid, amniotic fluid stem cells, gene expression, human embryonic stem cells, stem cells, transcriptome, c-KIT, RNA.