Ectopic PDX-1 expression directly reprograms human keratinocytes along pancreatic insulin-producing cells fate.
BACKGROUND
Cellular differentiation and lineage commitment have previously been considered irreversible processes. However, recent studies have indicated that differentiated adult cells can be reprogrammed to pluripotency and, in some cases, directly into alternate committed lineages. However, although pluripotent cells can be induced in numerous somatic cell sources, it was thought that inducing alternate committed lineages is primarily only possible in cells of developmentally related tissues. Here, we challenge this view and analyze whether direct adult cell reprogramming to alternate committed lineages can cross the boundaries of distinct developmental germ layers.


RESULTS
We ectopically expressed non-integrating pancreatic differentiation factors in ectoderm-derived human keratinocytes to determine whether these factors could directly induce endoderm-derived pancreatic lineage and β-cell-like function. We found that PDX-1 and to a lesser extent other pancreatic transcription factors, could rapidly and specifically activate pancreatic lineage and β-cell-like functional characteristics in ectoderm-derived human keratinocytes. Human keratinocytes transdifferentiated along the β cell lineage produced processed and secreted insulin in response to elevated glucose concentrations. Using irreversible lineage tracing for KRT-5 promoter activity, we present supporting evidence that insulin-positive cells induced by ectopic PDX-1 expression are generated in ectoderm derived keratinocytes.


CONCLUSIONS
These findings constitute the first demonstration of human ectoderm cells to endoderm derived pancreatic cells transdifferentiation. The study represents a proof of concept which suggests that transcription factors induced reprogramming is wider and more general developmental process than initially considered. These results expanded the arsenal of adult cells that can be used as a cell source for generating functional endocrine pancreatic cells. Directly reprogramming somatic cells into alternate desired tissues has important implications in developing patient-specific, regenerative medicine approaches.
Sheba Regenerative Medicine, Sheba Medical Center, Tel-Hashomer, Israel.
Michal
M
Mauda-Havakuk
Naomi
N
Litichever
Ellad
E
Chernichovski
Odelia
O
Nakar
Eyal
E
Winkler
Ram
R
Mazkereth
Arie
A
Orenstein
Eran
E
Bar-Meir
Philippe
P
Ravassard
Irit
I
Meivar-Levy
Sarah
S
Ferber
D016475:3T3 Cells; D000328:Adult; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D004475:Ectoderm / Q000166:cytology; D004707:Endoderm / Q000166:cytology; D005786:Gene Expression Regulation; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D050417:Insulin-Secreting Cells / Q000166:cytology*; D015603:Keratinocytes / Q000166:cytology* / Q000378:metabolism*; D051379:Mice; D010187:Pancreatic Hormones / Q000235:genetics; D051381:Rats; D015534:Trans-Activators / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics
D015415:Biomarkers; D018398:Homeodomain Proteins; D010187:Pancreatic Hormones; D015534:Trans-Activators; C084010:pancreatic and duodenal homeobox 1 protein