Cell Reprogramming Leaves the Test Tube

Harvard researchers report in the online version of Nature that they have developed a method to directly convert tissue cells (subscription) in a living mouse from one type into another. The breakthrough goes beyond the announcement last fall that scientists at the University of Wisconsin and the University of Kyoto independently developed induced pluripotent stem cells, which are adult cells reverted back to a stem-cell-like state.

The development will certainly spark the latest round of discussions over ethical questions involved in stem cell research, but despite the potential for work that builds on this discovery and iPS investigations, human embryonic stem cell research will likely still be an important component of the field for some time to come. Moreover, as James Thomson, leader of the Wisconsin team, made clear last year, hESC research was critical to understanding the hallmarks of pluripotency on the way to iPS cells; and in turn, the Harvard team offers a nod in its opening discussion to that iPS research.

Some researchers who spoke to the Post argued that this latest breakthrough could render human embryonic stem cell research unnecessary, but others pointed out that the science is still too young to make a determination about what is and is not useful. Scientists are still in the process of understanding the complexities of cell functions, and embryonic stem cells are a crucial tool for learning about the cell functions that will enable future cures.

“Embryonic stem cells offer a unique window in human disease and remain a key to the long-term progress of regenerative medicine,” Douglas A. Melton, one of the authors of the new study, told reporter Rob Stein.

The Washington Post also reports that at this early stage, human trials may be five years away. The new process uses a set of engineered adenoviruses to deliver a set of  genes to the target exocrine cells in the pancreases of diabetic mice. The combination of three transcription factors then converts these exocrine cells into beta-like cells, which produce insulin. The study indicates that this process appears to take place without the cells passing through a dedifferientiated state, or one similar to that of stem cells.

It is worth noting that the National Institutes of Health supported this remarkable discovery.

(HT to Alta Charo for forwarding the Post story.)

Tags: stem cells

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