Making Insulin: Pancreatic cells that have been reprogrammed to turn into insulin-¬producing beta cells, the cell type lost in type 1 diabetes, produce the growth factor VEGF (blue) and insulin (red and pink). Cell nuclei are marked in green.
A revolutionary technique converts one type of adult cell into another.
Source: “In vivo reprogramming of adult pancreatic exocrine cells to beta-cells”
Douglas Melton et al.
Nature,published online August 27, 2008
Results: By activating a specific set of genes in mice, scientists at the Harvard Stem Cell Institute converted a common type of pancreatic cell into a rarer, insulin-producing one. The research is the first to show that one type of fully formed adult cell can be directly converted into another type.
Why it matters: The technique might ultimately provide a way to replace the cells lost in diabetes and other diseases, such as Parkinson’s and amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease). The findings also open a new avenue of research in regenerative medicine–a field in which researchers develop therapies to repair or replace damaged cells and tissue. The technique provides an alternative to generating specific cell types from stem cells and transplanting them. Instead, scientists may be able to grow specialized cells directly from existing tissue in the body.
Methods: The researchers first identified a set of ninegenes that trigger the activity of other genes in pancreatic beta cells. Then they genetically engineered mature exocrine cells, which make up about 95 percent of the pancreas, to express combinations of the nine proteins, called transcription factors, that the genes produce. Eventually, they found a combination of three that transformed the exocrine cells into insulin-producing beta cells.
Next steps: Scientists at Harvard are now trying to repeat the results with human cells. Others are trying a similar approach with different cell types, such as the motor neurons lost in ALS.