Amniotic Fluid Cells Are More Efficiently Reprogrammed to Pluripotency Than Adult Cells

Abstract

Recently, cultured human adult skin cells were reprogrammed to induced pluripotent stem (iPS) cells, which have characteristics similar to human embryonic stem (hES) cells. Patient-derived iPS cells offer genetic and immunologic advantages for cell and tissue replacement or engineering. The efficiency of generating human iPS cells has been very low; therefore an easily and efficiently reprogrammed cell type is highly desired. Here, we demonstrate that terminally differentiated human amniotic fluid (AF) skin cells provide an accessible source for efficiently generating abundant-induced pluripotent stem (AF-iPS) cells. By induction of pluripotency with the transcription factor quartet (OCT3/4, SOX2, KLF4, and c-MYC) the terminally differentiated, cultured AF skin cells formed iPS colonies approximately twice as fast and yielded nearly a two-hundred percent increase in number, compared to cultured adult skin cells. AF-iPS cells were identical to hES cells for morphological and growth characteristics, antigenic stem cell markers, stem cell gene expression, telomerase activity, in vitro and in vivo differentiation into the three germ layers and for their capacity to form embryoid bodies (EBs) and teratomas. Our findings provide a biological interesting conclusion that these fetal AF cells are more rapidly, easily, and efficiently reprogrammed to pluripotency than neonatal and adult cells. AF-iPS cells may have a "young," more embryonic like epigenetic background, which may facilitate and accelerate pluripotency. The ability to efficiently and rapidly reprogram terminally differentiated AF skin cells and generate induced pluripotent stem cells provides an abundant iPS cell source for various basic studies and a potential for future patient-specific personalized therapies.

Endogenous KLF4 Expression in Human Fetal Endothelial Cells Allows for Reprogramming to Pluripotency With Just OCT3/4 and SOX2—Brief Report

“…To create less manipulated iPSCs, one approach is to decrease the number of reprogramming factors used, especially oncogenes. 8 5 Two recent studies show iPSC generation from amniotic fluid-derived cells 10 and HUVECs, 11 but with 4 factors. We demonstrate that only 2 nononcogenic factors, OCT3/4 and SOX2, were required to reprogram HUVECs, likely because of the high endogenous expression of KLF4 in these cells, 12 as well as the proliferative advantage inherent to fetal cells.…”

Amniotic Fluid Stem Cells

“…Furthermore, recently induced pluripotent stem (iPS) cells have been prepared from cells derived from amniotic fluid (AF-iPS), and have shown high efficiency of transformation and colony formation after just six days (Li C et al, 2009). Although not fully understood, this is probably due to the presence of an epigenetic status closer to the embryonic state (Galende E et al, 2010). Reprogramming of somatic cells using the four specific factors, Oct4, Sox2, Klf4, and c-Myc has the potential to provide pluripotent stem cells specific for patients, thus AFiPS seem to be more easily reprogrammed to pluripotency compared to adult cells or cells from neonates.…”

Advancements in reprogramming strategies for the generation of induced pluripotent stem cells

“…Anchan et al [91] and Galende et al [92] have demonstrated that cells found in the amniotic fluid generate iPSCs at a higher rate of approximately 200% increase and at 5-6 days compared to about 10 days or more than 2 weeks from keratinocytes or mouse embryonic fibroblasts. Anchan et al [91] used only two reprogramming factors (Klf4 and c-Myc) for pluripotency induction compared to the usual quartet cocktail.…”