“Latest Stem Cells News”

Never mind facial masks and exfoliating scrubs, skin takes care of itself. Stem cells located within the skin actively generate differentiating cells that can ultimately form either the body surface or the hairs that emanate from it. In addition, these stem cells are able to replenish themselves, continually rejuvenating skin and hair. Now, researchers at Rockefeller University have identified two proteins that enable these skin stem cells to undertake this continuous process of self-renewal.

The work, published in Nature Genetics, brings new details to the understanding of how stem cells maintain — and lose — their status as stem cells and are able to specialize into various types of cells. It also further dissects a ubiquitous Rube Goldberg-like pathway whose molecular gears and levers play an important role in activating stem cells to divide and transform into tissue-making cells.

Lead researcher Elaine Fuchs, head of the Laboratory of Mammalian Cell Biology and Development, and first author Hoang Nguyen, a former postdoc in the lab, worked with mice engineered to lack the proteins TCF3 and TCF4, which reside in the nucleus of skin stem cells, where they bind to DNA to turn genes off that would otherwise cause the stem cells to differentiate. They found that without TCF3 and TCF4, all of the layers of the mice’s skin still develop properly, but they cannot be maintained.

“The epidermal stem cells — one of the types of stem cells in the skin — lose their capacity to self-renew and replace skin cells that have died,” says Nguyen, who is now an assistant (…)

from http://www.sciencedaily.com/releases/2009/09/090927152828.htm

Incoming search terms:

Whitehead Institute researchers have developed a novel method of removing potential cancer-causing genes during the reprogramming of skin cells from Parkinson’s disease patients into an embryonic-stem-cell-like state. Scientists were then able to use the resulting induced pluripotent stem (iPS) cells to derive dopamine-producing neurons, the cell type that degenerates in Parkinson’s disease patients.

The work marks the first time researchers have generated human iPS cells that have maintained their embryonic stem-cell-like properties after the removal of reprogramming genes. The findings are published in the March 6 edition of the journal Cell.

Removing the reprogramming genes is also important because of those genes’ effect on an iPS cell‘s gene expression (a measure of which genes the cell is using and how much it’s using those genes). When the researchers compared the gene expressions of human embryonic stem cells to iPS cells with and without the reprogramming factors, iPS cells without the reprogramming genes had a gene expression closer to human embryonic stem cells than to the same iPS cells that still contained the reprogramming genes.

“The reprogramming factors are known to bind to and affect the expression of 3,000 genes in the entire genome, so having artificial expression of those genes will change the cell’s overall gene expression,” Dirk Hockemeyer, who is also a co-author of the Cell article. “That’s why the four reprogramming genes can mess up the system so much. From now on, it will be tough for researchers to leave the reprogramming genes in iPS cells.”

from http://web.mit.edu/newsoffice/2009/parkinsons-stem-0305.html

Incoming search terms:

The prospect of treating genetic diseases with corrected stem cells grown from patients’ own bodies has moved closer, after the results of a remarkable experiment.

Scientists have successfully reprogrammed skin tissue from people with a rare form of anaemia to create powerful stem cells, while at the same time rectifying the genetic defect that causes the condition.

The corrected stem cells could be grown into blood precursor cells for therapy. As these would carry a patient’s own DNA, except for the mutation responsible for the illness, they could be transplanted without risk of rejection by the body’s immune system.

Though the research team, from Spain and the United States, has yet to use the cells to treat patients, and several important hurdles still remain, the achievement has been hailed as a significant advance for stem cell research.

It suggests that it should eventually be possible to treat many inherited conditions by making disease-free stem cells from their own bodies. (…)

The cells were infected with a genetically modified virus to correct the gene that causes Fanconi anaemia. These were then reprogrammed into an embryo-like state by modifying further genes, to create versatile master cells known as induced pluripotent stem cells (IPS cells). (…)

Chris Mathew, Professor of Molecular Genetics at King’s College London, said: “This is an important development for families with this rare, inherited blood disorder. The patients have low numbers of blood stem cells in their bone marrow, so there are very few target cells to correct by gene therapy.

“The new research shows that it is possible to reprogramme skin cells from these patients into stem cells in which the genetic defect has been corrected. In future it may become possible to transfer the corrected stem cells back into the patient, but much work remains to be done.”

Read full article on Times Online

Incoming search terms:

Hebrew University of Jerusalem

Researchers at the Hebrew University of Jerusalem discovered a method to potentially eliminate the tumor-risk factor in utilizing human embryonic stem cells, said the university on Wednesday.
The researchers’ work paves the way for further progress in the promising field of stem cell therapy, said the press release of the university sent to Xinhua.

According to the release, human embryonic stem cells are theoretically capable of differentiation to all cells of the mature human body (and are hence defined as “pluripotent“).
This ability, along with the ability to remain undifferentiated indefinitely in culture, make regenerative medicine using human embryonic stem cells a potentially unprecedented tool for the treatment of various diseases, including diabetes, Parkinson’s disease and heart failure.

Incoming search terms:

In a genetic engineering breakthrough that could help everyone from bed-ridden patients to elite athletes, a team of American researchers—including 2007 Nobel Prize winner Mario R. Capecchi—have created a “switch” that allows mutations or light signals to be turned on in muscle stem cells to monitor muscle regeneration in a living mammal. For humans, this work could lead to a genetic switch, or drug, that allows people to grow new muscle cells to replace those that are damaged, worn out, or not working for other reasons (e.g., muscular dystrophy). In addition, this same discovery also gives researchers a new tool for the study of difficult-to-treat muscle cancers. The full report containing details of this advance is available online in The FASEB Journal.

Incoming search terms:

Researchers have created mammalian cells containing a single set of chromosomes in research funded by the Wellcome Trust and EMBO. The technique should allow scientists to better establish the relationships between genes and their function.

Mammal cells usually contain two sets of chromosomes – one set inherited from the mother and one from the father. The genetic information contained in these chromosome sets helps determine how our bodies develop. Changes in this genetic code can lead to or increase the risk of developing disease.

To understand how our genes function, scientists manipulate the genes in animal models – such as the fruit fly, zebrafish and mice – and observe the effects of these changes. However, as each cell contains two copies of each chromosome, determining the link between a genetic change and its physical effect – or ‘phenotype’ – is immensely complex.

Incoming search terms: