Abstract
Human embryonic stem (hES) cells can be differentiated into pancreatic endoderm structures in vitro. The study was performed to determine whether induced pluripotent stem (iPS) cells can be differentiated into similar structures with comparable efficiency. We compared the ability of hES cells and iPS cells derived from human epidermal keratinocytes to progressively differentiate into pancreatic endoderm. Human foreskin keratinocytes were reprogrammed to pluripotency by transduction with retroviruses encoding Oct4, Sox2, and Klf4. The resulting keratinocyte-derived iPS (KiPS) cell lines and a hES cell line were subjected to a modified pancreatic endoderm differentiation protocol. Cells and embryoid-body structures derived from both hES and KiPS cells were compared at different stages of development for expression of stem cell and differentiation markers, including Sox2, Oct4, Mixl1, Brachyury, Gsc, FoxA2, Sox17, Hnf4α, Hnf1β, Nkx2.2, Nkx6.1, Hex, Isl1, Pdx1, and Slc2A, via Taqman real-time PCR, flow-cytometry, and/or immunocytochemistry. hES cells and KiPS cells expressed similar levels of the stem cell factors Sox2 and Oct4. Upon differentiation, both cell types underwent remarkably similar changes in gene expression. They acquired the definitive endoderm markers Sox17 and FoxA2. Most Sox17+ and FoxA2+ cells co-expressed Hnf4α and Hnf1β, found in the primitive gut tube, a pancreas precursor. Most FoxA2+ cells were also Pdx1+, and many expressed Nkx2.2, Nkx6.1, and Isl1. Keratinocyte-derived iPS cells can be differentiated into pancreatic endoderm, and the efficiency of this process is comparable to that seen for hES cells. Thus keratinocytes have the potential to serve as a source of patient-specific pancreatic endoderm for transplantation.
Highlights
The pancreas arises from the definitive endoderm, a specialized epithelium that forms the primitive gut tube, and specifies the structures that differentiate into the organs arising from this germ layer
Dorsal and ventral buds originating from the gut tube fuse to form the posterior foregut
Factors produced by the notochord, such as activin A and fibroblast growth factor 7 (FGF7), coupled with retinoic acid (RA) signaling and inhibition of sonic hedgehog signaling, specify expression of the key transcription factor Pdx1 by the dorsal pancreatic endoderm [21, 22]
Summary
Human embryonic stem (hES) cells can be differentiated into pancreatic endoderm structures in vitro. The discovery that mouse fibroblasts can be reprogrammed into induced pluripotent stem (iPS) cells by transduction of four key transcription factors (Oct, Sox, Klf, and c-Myc) provided a potential solution to this ethical issue, and brought forth the notion that derivation of tissues from patient-specific stem cells is possible [14]. These studies were replicated by others [15], and extended to the generation of human iPS cells from fibroblasts [16,17,18]. We monitored the kinetics of marker expressions at different stages of differentiation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
