Howard Hughes Medical Institute researchers have converted adult pancreatic cells into insulin-producing beta cells in living mice. This is a first because the researchers directly changed the functional identity of adult cells without using embryonic stem cells or relying on techniques that reverse a cell’s genetic programming to its earliest stages.
The investigators repurposed the adult cells quickly by using viruses to shuttle just three regulatory genes that triggered the remarkable developmental changes. It took only a brief blip of activity by the regulatory genes to imbue the cells with their new job descriptions, which they have retained for as long as nine months.
The experiments, which are reported in an advance online publication in the journal Nature, realize a longtime goal in regenerative medicine: To produce specialized repair cells directly from a pool of adult cells that are healthy, abundant and easily obtained. Until now, repair cells have been generated from embryonic stem cells or more recently from pluripotent stem cells created by fully reprogramming adult cells.
“What this shows is that you can go directly from one type of adult cell to another, without going back to the beginning,” said Douglas A. Melton, a Howard Hughes Medical Institute (HHMI) investigator at Harvard University and co-director of the Harvard Stem Cell Institute. “You could say, for example, it’s like turning a scientist into a lawyer without sending her all the way back to kindergarten.”
In this case, the strategy was used in mice to convert exocrine cells, which compose 95 percent of the pancreas, to the relatively scarce beta cells that produce insulin. For more than a decade, Melton has studied how embryonic stem cells give rise to the pancreas and its insulin-producing beta cells, which are destroyed in patients with type 1 diabetes. Ultimately, his studies could lead to ways to generate new pancreatic beta cells that could be used as a treatment for diabetes. However, Melton cautioned that the new results are a proof of principle and do not have immediate medical applications.
Release date: August 27, 2008
Source: Howard Hughes Medical Institute