For the first set of experiments, first author Trond Aasen, Ph.D., a postdoctoral researcher at the Center of Regenerative Medicine in Barcelona, used viral vectors to slip the genes for the master regulators Oct4, Sox2, as well as Klf4 and c-Myc into keratinocytes cultured from human skin explants. After only 10 days instead of the more typical three to four weeks one out of 100 hundred cells grew into a tiny colony with all the markings of a typical human embryonic stem cell colony.
The researchers then successfully prodded what they call keratinocyte-derived iPS cells or KiPS cells to distinguish them from fibroblast-derived iPS cells into becoming all the cell types in the human body, including heart muscle cells and dopamine-producing neurons, which are affected by Parkinson's disease.
Taking advantage of the high efficiency of the keratinocyte reprogramming process, Aasen decided to test whether he could establish KiPS cells from minute amounts of biological samples. "We plucked a single hair from a co-worker's scalp and cultured the keratinocytes, which are found in the outer root sheet area," recalls Aasen. He then successfully reprogrammed these cells into bona fide KiPS cells.
Just why keratinocytes appear to be much more malleable than other cell types is still an open question. "We checked a whole rainbow of cells and found keratinocytes to be the easiest to be reprogrammed," says Belmonte. "It is still not clear exactly why that is and knowing it will be very important for the technology to develop fully," he speculates.
They researchers did find one hint, though. When they compared the expressi
|Contact: Mauricio Minotta|