The developers of the new technique at the University
of California, Irvine (UCI) describe it as a dramatically improved method for
genetically manipulating human embryonic stem cells.
As regards how the technique works, the researchers
have revealed that it blends two existing cell-handling methods to improve cell
survival rates, and to increase the efficiency of inserting DNA into cells.
They claim that this procedure is 100 times more
efficient than current methods at producing human embryonic stem cells with
desired genetic alterations.
"The ability to generate large quantities of cells
with altered genes opens the door to new research into many devastating
disorders," said Peter Donovan, professor of biological chemistry and
developmental and cell biology at UCI, and co-director of the UCI Sue and Bill
Gross Stem Cell Research Center.
"Not only will it allow us to study diseases more
in-depth, it also could be a key step in the successful development of future
stem cell therapies," he added.
In a previous study, which Professor Donovan carried
out in collaboration with Assistant Adjunct Professor Leslie Lock, the research
team had identified proteins called growth factors that help keep cells alive
by telling them how to behave or remain a stem cell.
In the current study, Professor Donovan's team used
the same growth factors to keep cells alive, and then inserted DNA into the
cells using a technique called nucleofection — a process in which electrical
pulses are used to punch tiny holes in the outer layer of a cell.
The researchers say that with nucleofection,
scientists can introduce into cells DNA that makes proteins that glow green
under a special light.
In a report describing the process, published in the
journal Stem Cells, they say that the green colour makes it possible to track
the movement of cells once they are transplanted into an animal model, which in
turn makes it easier to identify the cells during safety studies of potential
stem cell therapies.
These days, DNA are inserted into cells using
chemicals, but that method can kill the cells sometimes, and is inefficient at
transferring genetic information.
UCI scientists reckon that for every one genetically
altered cell generated using the chemical method, the new growth
factor/nucleofection method produces between 10 and 100 successfully modified
"Before our technique, genetic modification of human
embryonic stem cells largely was inefficient. This is a stepping stone for
bigger things to come," said Kristi Hohenstein, a stem cell scientist in
The researchers say that with the new technique,
scientists can develop populations of cells with abnormalities that lead to
disease, and study them to learn more about the disorder and how it is caused.
According to them,
the novel method may also facilitate the correction of the disorder in stem
cells so that healthy cells can be used in a treatment.