Home' Technology Review : July August 2009 Contents FEATURE STORY
TECHNOLOGY REVIEW JULY/AUGUST
On the second floor of a building in one of South San
Francisco's numerous business parks, a new biotech
company has set up shop. The walls sport a fresh coat
of white paint, and the bench tops are shiny and bare.
The tile floors are still glossy, and an expensive new cell-sorting
machine sits, untouched, on the loading dock downstairs.
The building's new inhabitant, iZumi Bio, is pursuing a tech-
nology as new and full of promise as the lab itself---a technology
that's moving faster than the company can fill its empty space. It
revolves around induced pluripotent stem (iPS) cells: adult cells
genetically reprogrammed to act like embryonic stem cells, which
can turn into just about any type of cell in the human body.
Scientists have been talking about the medical promise of stem
cells for more than a decade, even before human embryonic stem
cells were successfully isolated in 1998. Most of the public attention
has focused on their regenerative power: since stem cells can renew
themselves and di erentiate into specialized cell types, they could
potentially be used to build replacement organs, heal spinal-cord
injuries, or repair damaged brain tissue. But the research world has
also pursued another, even broader-reaching goal: using the cells
of patients with various illnesses to derive pluripotent stem cells,
which can give rise not just to the specialized cells in a particular
organ or tissue but to virtually any cell type. Those cells could be
used to create laboratory models of disease. For example, a cell from
a Parkinson's patient could be turned into a neuron, which would
exhibit the progressive molecular changes at work in the neurode-
generative disorder. This type of tool could capture the details of
human disease with unprecedented accuracy, and it could revolu-
tionize the way researchers search for new treatments.
Studying human disease in the lab is an enormously challeng-
ing task. It's di cult to obtain brain tissue from a living Alzheim-
er's patient, for example, and impossible to study how that tissue
changes as the disease progresses. Animal models can o er only
rough approximations of a human illness, capturing at best a
few of its symptoms or causes. But iPS cells could yield a much
more comprehensive picture. Because each cell line comes from
a human patient, the cells reflect the complex array of factors that
led to the patient's disease: the genetic mutations, the e ects of
environmental history. And because those cells can be prodded
to develop into a variety of tissue types, scientists can watch the
disease unfold in a petri dish. They can observe, for example, the
subtle molecular changes that take place in the neurons of a patient
with Alzheimer's long before the telltale signs of the disease, such
as amyloid plaques, can be seen in the brain. It's the di erence
between trying to piece together the details of a plane crash from
photos of the wreckage and watching a video of the crash from
every angle, with the ability to stop, zoom in, and rewind at will.
"The past two years have been nothing short of a revolution,"
says John Dimos, a senior scientist at iZumi. "These cells didn't
really exist two years ago. This is all brand-new technology, and
it's opening up the potential for brand-new science." The company
plans to take advantage of that potential by developing a bank of
iPS cells from patients with various diseases and using the cells
to screen candidates for drug development.
Thousands of other labs are jumping at the chance to use iPS
cells as well---whether to create new disease models, to study tissue
development, or even to figure out how to build tissue for transplan-
tation. Biologists say the field is charged with a kind of energy not
seen since soon after the structure of DNA was discovered. "This
is a really rare phenomenon in the biological research community,"
says Sheng Ding, a chemist at the Scripps Research Institute in La
Jolla, CA. "It's a sensation, really. Everyone, more or less, is working
on using iPS-cell technology for their specific research interest."
STEM CELLS 2.0
Scientists have been searching for ways to directly reprogram
adult cells for decades. That hunt has been pushed forward by the
desire to develop an alternative to human embryonic stem cells,
AN ALTERNATIVE WAY TO MAKE
STEM CELLS COULD OPEN A
WINDOW ON HUMAN DISEASE.
By LAUREN GRAVITZ
JUNYING YU/UNIVERSITY OF WISCONSIN-MADISON
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