Johns Hopkins researchers develop human stem cell line containing
sickle cell anemia mutation
Improved adult cell reprogramming methods open doors for disease
research
Researchers at Johns Hopkins have established a human cell-based
system for studying sickle cell anemia by reprogramming somatic cells
to an embryonic stem cell like state. Publishing online in Stem Cells
on May 29, the team describes a faster and more efficient method of
reprogramming cells that might speed the development of stem cell
therapies.
"We hope our new cell lines can open the doors for researchers who
study diseases like sickle cell anemia that are limited by the lack
of good experimental models," says Linzhao Cheng, Ph.D., an associate
professor of gynecology and obstetrics, medicine and oncology and a
member of the Johns Hopkins Institute for Cell Engineering.
The research team first sought to improve previously established
methods for reprogramming of adult cells into so-called induced
pluripotent stem (iPS) cells, which look and behave similarly to
embryonic stem cells and can differentiate into many different cell
types. After testing several different genes, they were able to
improve reprogramming efficiency by adding a viral protein known as
SV40 large T antigen.
Using both fetal and adult human skin cells, the researchers
introduced the four genes previously reported sufficient for cell
reprogramming and compared the efficiency of reprogramming in the
presence or absence of large T antigen. Without large T, cells form
embryonic stem cell-like clusters in three to four weeks. With large
T, the cells started looking like embryonic stem cells in just 12 to
14 days.
"Not only did T speed up reprogramming, we also found that it
increases the total number of reprogrammed cells, which is great
because often in reprogramming, not all cells go all the way," says
Cheng, who explains that rigorous follow-up tests are required to
determine if the reprogrammed cells really behave like pluripotent
embryonic stem cells. "Many of them look right but they're probably
just half cooked-like a boiled egg, you just can't tell the
difference by looking at the outside," he says.
Having established a faster, more efficient method, the team then
reprogrammed human cells that contain the mutation associated with
sickle cell anemia. Embryonic stem cell-like clusters were visible 14
days after they initiated reprogramming and from these clusters the
researchers established three different cell lines that both look and
behave like human embryonic stem cells.
"One challenge to studying blood diseases like sickle cell anemia is
that blood stem cells can't be kept alive for very long in the lab,
so researchers need to keep returning to patients for more cells to
study," says Cheng. "Having these new cell lines available might
enable some bigger projects, like screening for potential drugs."
###
The research was funded by the National Institutes of Health and the
Johns Hopkins Institute for Cell Engineering.
Authors on the paper are Prashant Mali, Zhaohui Ye, Holly Hammond,
Xiaobing Yu, Jeffrey Lin, Guibin Chen, Jizhong Zou and Cheng, all of
Hopkins.
On the Web:
http://www.hopkins-
http://stemcells.
Public release date: 29-May-2008
Contact: Audrey Huang
audrey@jhmi.
410-614-5105
Johns Hopkins Medical Institutions
http://www.eurekale
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StemCells subscribers may also be interested in these sites:
Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
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