In the last three years, a new technique for reprogramming adult cells has given scientists an easier and less controversial way to harness the power of embryonic-like stem cells to study human disease from its earliest beginnings in hopes of gleaning new insights into the root causes of disease and developing new therapies.
But the reprogrammed cells, known as induced pluripotent stem (iPS) cells, are different from embryonic stem cells in their ability to model a human genetic disease, a new cell-to-cell comparison shows.
"This is the first example where we can clearly show induced pluripotent stem cells and embryonic stem cells behave differently in a disease model," said co-senior author George Daley, Director of the Stem Cell Transplantation Program at Children's Hospital Boston. Daley's team has turned patient cells back into stem cells for a range of diseases.
In the new study in the May 7 Cell Stem Cell, the researchers made iPS cells from the skin cells of three patients with fragile X syndrome, the most common form of inherited mental retardation in boys. By almost every measure, virtually the entire genome was dialed back in time. The key exception was the disease-causing gene, which becomes inactivated to cause the disease, and did not get turned back on in the iPS cells.
"Both iPS and embryonic stem cell lines have the same mutation," said co-senior author Nissim Benvenisty, director of the Stem Cell Unit at the Hebrew University of Jerusalem, whose lab established an embryonic stem cell model of fragile X syndrome three years ago at a time when such research was severely restricted in the United States. "However, we saw a difference between the two systems."
About one-third of children with fragile X have behavioral symptoms that overlap with autism. Scientists hope a stem cell model of fragile X will help them study what goes wrong and test drugs that may help treat both abnormal conditions.<
|Contact: Bess Andrews|
Children's Hospital Boston