The process of reprogramming mature cells into a stem-cell-like state can be accelerated, a Nature paper reveals. The results shed light on the processes underlying the production of induced pluripotent stem (iPS) cells -- the ethical 'embryo-free' alternative to stem cells touted to hold great promise for regenerative medicine.
Rudolf Jaenisch and colleagues studied the ability of mature immune cells to generate iPS cells upon continued exposure to four previously defined reprogramming factors. Nearly all of the donor cells were able to form iPS cells, although they took different lengths of time to do so. The results indicate that reprogramming is not the sole preserve of an elite subset of cells, but a continuous, essentially random process that almost any cell can undergo given the right conditions. Critically, the process can be accelerated, and the team identify two methods that do just that. One method depends on the rate at which the donor cells divide; the other method does not. So the results also establish a new model in which cell division number, rather than the absolute time of reprogramming factor expression, drives the kinetics of iPS cell production. Author contact: Rudolf Jaenisch (Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA, USA) E-mail: jaenisch@wi.mit.edu Abstract available online. (C) Nature press release.
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