First a drop, then the deluge. Last week, scientists at Harvard University and Columbia University announced that they had proved the viability of a new way to study a disease--amyotrophic lateral sclerosis--by reprogramming cells from a patient to become pluripotent stem cells, which can then become any type of cell or tissue. Yesterday, another Harvard team announced that it had generated disease-specific cell lines for nine other genetic diseases, including Parkinson's disease. The cells will enable researchers to use lab-grown cultures to study how the diseases develop.
Obtained by the same method as the previous advance, the flood of results "opens the door to a new way of studying degenerative diseases," said Harvard diabetes researcher Douglas Melton at a press conference yesterday. The team, headed by blood cancer researcher In-Hyun Park, published its paper online today in Cell.
The work marks yet another proof of the viability of induced pluripotent stem (iPS) cells. Such stem cells are generated by introducing genes that reprogram adult cells. The only alternative for generating patient-specific cell lines is a process called therapeutic cloning, a technique that involves transplanting the nucleus from an adult cell into an enucleated egg. Still unproven in humans, that process is controversial because it requires the destruction of embryos.
The new lines were derived from skin cells and in one case bone marrow biopsies from patients with complex genetic diseases such as childhood diabetes, as well as rare single-gene disorders including Huntington's disease. Researchers should be able to cultivate iPS cells into cell types they want to study--for example, dopamine neurons in the case of Parkinson's or pancreatic cells for diabetes--and find out where and how they go wrong. The cell cultures can also be used for testing new drugs against these diseases.
"This is just the first wave of diseases" that the Harvard group plans to get iPS cells from, said stem cell researcher George Daley of Children's Hospital Boston. And there's no limit to the number of iPS lines they hope to generate. As Melton pointed out, "there could be 50 different ways to get type 1 diabetes," and he wants cell lines representing all of them.
Scientists anticipate that they'll be able to use iPS cells for much of the research they have been planning with human embryonic stem (ES) cells. But work with ES cells has been bogged down by a host of ethical, practical, and intellectual property issues. Many of the problems are swept away with iPS cells. Daley said Harvard intends to produce 50 to 200 lines a year, making them available "at a nominal cost" to other researchers. At a press conference, Harvard officials also announced the establishment of a new iPS "core" lab at the Harvard Stem Cell Institute to speed the development of the new cell types and their dissemination to researchers around the world.
- Adenosine deaminase deficiency-related severe combined immunodeficiency (ADA-SCID)
- Shwachman-Bodian-Diamond syndrome
- Gaucher disease
- Muscular dystrophy (two types)
- Parkinson's disease
- Huntington's disease
- Type 1 diabetes
- Lesch-Nyhan syndrome
- Down syndrome