Scientists identifies gene that regulates blood-forming fetal stem cells

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Genes That Control Embryonic Stem Cell Fate Identified

Scientists have identified about two dozen genes that control embryonic stem cell fate. The genes may either prod or restrain stem cells from drifting into a kind of limbo, they suspect. The limbo lies between the embryonic stage and fully differentiated, or specialized, cells, such as bone, muscle or fat. By knowing the genes and proteins that control a cell’s progress toward the differentiated form, researchers may be able to accelerate the process — a potential boon for the use of stem cells in therapy or the study of some degenerative diseases, the scientists say. Their finding comes from the first large-scale search for genes crucial to embryonic stem cells. The research was carried out by a team at the University of California. [lien] [EN]

Scientists clone mice from adult skin stem cells

For cells that hold so much promise, stem cells’ potential has so far gone largely untapped. But new research from Rockefeller University and Howard Hughes Medical Institute scientists now shows that adult stem cells taken from skin can be used to clone mice using a procedure called nuclear transfer. The findings are reported in the Feb. 12 online edition of the Proceedings of the National Academy of Sciences. Caption: Using a technique called nuclear transfer, mice were cloned using adult skin stem cells (right) and a more differentiated type of skin cell (left). The mouse on the right is almost two years old and the mouse on the right is one and a half. Credit: Jinsong Li, Postdoc in the Mombaerts Laboratory, Rockefeller University Embryonic stem cells have received the most press for their potential to generate healthy cells and tissues that could replace damaged or diseased organs. [lien] [EN]

UC Irvine scientists find new way to sort stem cells

UC Irvine scientists have found a new way to sort stem cells that should be quicker, easier and more cost-effective than current methods. The technique could in the future expedite therapies for people with conditions ranging from brain and spinal cord damage to Alzheimer's and Parkinson's diseases. The method uses electrodes on a tiny, inch-long glass slide to sort cells by their electric charges and has been used in cancer research. The stem cell field suffers from a lack of tools for identifying and sorting cells. This important discovery could add a new tool to current sorting methods, which generally require expensive, bulky equipment. “For therapeutic purposes, we want stem cells to turn into specific cell types once they have been transplanted. [lien] [EN]

Scientists Discover Key to Growing New Stem Cells

Scientists at Duke University Medical Center have demonstrated they can grow human stem cells in the laboratory by blocking an enzyme that naturally triggers stem cells to mature and differentiate into specialized cells. The discovery may enable scientists to rapidly grow stem cells and transplant them into patients with blood disorders, immune defects and select genetic diseases, said the Duke researchers. Stem cells are the most flexible cells in the body, continually dividing into new stem cells or into specialized cells that carry out specific roles in the body. But little is known about how stem cells choose their fate. The Duke team focused on “hematopoietic” or blood stem cells. [lien] [EN]

In a major breakthrough scientists find new way to create stem cells without embryos

Stem cells with the capacity to form any type of tissue can be created from adult cells without destroying embryos, according to new research that suggests a way of sidestepping ethical controversy over the field. Three separate teams of scientists have used genetic trickery to wind back the biological clock of mature skin cells from mice, to give them the unlimited potential of stem cells that are normally found only in embryos. Though it remains uncertain whether the same technique would work in humans, the successes raise the prospect that powerful master cells for use in medicine and research could one day be created from adult bodies, removing any need to use embryos. Read the article at Times Online site [lien] [EN]

Scientists discover new way to enhance stem cells to stimulate muscle regeneration

Scientists at the Ottawa Hospital Research Institute (OHRI) and the University of Ottawa have discovered a powerful new way to stimulate muscle regeneration, paving the way for new treatments for debilitating conditions such as muscular dystrophy. The research, to be published in the June 5 issue of Cell Stem Cell, shows for the first time that a protein called Wnt7a increases the number of stem cells in muscle tissue, leading to accelerated growth and repair of skeletal muscle. “This discovery shows us that by targeting stem cells to boost their numbers, we can improve the body’s ability to repair muscle tissue,” said senior author Dr. Michael Rudnicki. Dr. Rudnicki is the Scientific Director of Canada’s Stem Cell Network and a Senior Scientist at OHRI and Director of OHRI’s Sprott Centre for Stem Cell Research. [lien] [EN]

Researchers map gene that regulates adult stem cell growth

The researchers genetically mapped a stem cell gene and its protein product, Laxetin, and building on that effort, carried the investigation all the way through to the identification of the gene itself. This is the first time such a complete study on a stem cell gene has been carried out. This particular gene is important because it helps regulate the number of adult stem cells in the body, particularly in bone marrow. Now that it has been identified, researchers hope the gene, along with its protein product Latexin, can be used clinically, such as for ramping up the stem cell count in cancer patients undergoing chemotherapy and bone marrow transplantation. The researchers agreed that this very process is not only interesting. [lien] [EN]

Scientists unlock mystery of embryonic stem cell signaling pathway

A newly discovered small molecule called IQ-1 plays a key role in preventing embryonic stem cells from differentiating into one or more specific cell types, allowing them to instead continue growing and dividing indefinitely, according to research performed by a team of scientists who have recently joined the stem-cell research efforts at the Keck School of Medicine of the University of Southern California. Their findings are being published in the Proceedings of the National Academy of Sciences. This discovery takes scientists another step closer to being able to grow embryonic stem cells without the “feeder layer” of mouse fibroblast cells that is essential for maintaining the pluripotency of embryonic stem cells. [lien] [EN]

Scientists identify gene that predicts post-surgical survival from brain metastasis of breast cancer patients

Researchers at the National Cancer Institute have identified a gene that may play a role in breast cancer metastasis to the brain, according to a report in Molecular Cancer Research, a journal of the American Association for Cancer Research. Diane Palmieri, Ph.D. a staff scientist at the NCI, said Hexokinase 2 overexpression was more highly expressed in brain metastasis in patients with breast cancer than in primary breast tumors. “Importantly, this study was conducted in human tissue rather than animal models, so we are able to extrapolate data without the problems inherent in animal studies,” said Palmieri. Brunhilde Felding-Habermann, Ph.D. an associate professor at The Scripps Research Institute, said the findings are a major step forward in potential breast cancer treatments. [lien] [EN]

Stem Cells Restore Muscle In Mice With Muscular Dystrophy

Researchers at the Joslin Diabetes Center have demonstrated for the first time that transplanted muscle stem cells can both improve muscle function in animals with a form of muscular dystrophy and replenish the stem cell population for use in the repair of future muscle injuries. “I’m very excited about this,” said lead author Amy J. Wagers, Ph.D., Principal Investigator in the Joslin Section on Developmental and Stem Cell Biology, principal faculty member at the Harvard Stem Cell Institute and Assistant Professor of Stem Cell and Regenerative Biology at Harvard University. “This study indicates the presence of renewing muscle stem cells in adult skeletal muscle and demonstrates the potential benefit of stem cell therapy for the treatment of muscle degenerative diseases such as muscular dystrophy. [lien] [EN]

Scientists identify gene that may make humans more vulnerable to pulmonary tuberculosis

Researchers from the Genome Institute of Singapore (GIS) and its collaborators have now identified for the first time a new gene that may confer susceptibility to pulmonary tuberculosis. Their findings, published October 10 in the open access journal PLoS Genetics, reported that a gene named Toll-like receptor 8 (TLR8), previously shown only to recognize some factors from viruses such as the human immunodeficiency virus (HIV), has a probable role in human susceptibility to Mycobacterium tuberculosis infections. The results from the study also found that males are more susceptible than females. Pulmonary tuberculosis is a contagious lung disease caused by a bacterium known as Mycobacterium tuberculosis (M. tuberculosis). Although a third of the world population is infected with M. [lien] [EN]

When smell cells fail they call in stem cell reserves

Hopkins researchers have identified a backup supply of stem cells that can repair the most severe damage to the nerves responsible for our sense of smell. These reservists normally lie around and do nothing, but when neighboring cells die, the scientists say, the stem cells jump into action. A report on the discovery will appear online next week in Nature Neuroscience. “These stem cells act like the Army Reserves of our nose,” explains lead author Randall Reed, Ph.D., a professor of neuroscience at Johns Hopkins, “supporting a class of active-duty stem cells that help repair normal wear and tear. They don't come in until things are really bad.” The only nerve cells in the body to run directly from the brain to the outside world. [lien] [EN]

The making of an intestinal stem cell

Researchers have found the factor that makes the difference between a stem cell in the intestine and any other cell. The discovery reported in the March 6th issue of the journal Cell, a Cell Press publication, is an essential step toward understanding the biology of the stem cells, which are responsible for replenishing all other cells in the most rapidly self-renewing tissue in mammals. It may also have implications for colon cancer, according to the researchers. The report finds evidence that a transcription factor called Achaete scute-like 2 (Ascl2) switches on the stem cell program in intestinal cells. Transcription factors are genes that control other genes. “This transcription factor makes these stem cells tick. [lien] [EN]

First compound that specifically kills cancer stem cells found

he cancer stem cells that drive tumor growth and resist chemotherapies and radiation treatments that kill other cancer cells aren’t invincible after all. Researchers reporting online on August 3th in the journal Cell, a Cell Press publication, have discovered the first compound that targets those cancer stem cells directly. “It wasn’t clear it would be possible to find compounds that selectively kill cancer stem cells,” said Piyush Gupta of the Massachusetts Institute of Technology (MIT) and the Broad Institute. “We’ve shown it can be done.” The team including MIT’s Robert Weinberg and the Broad Institute’s Eric Lander developed a new high-throughput screening method that makes it possible for the first time to systematically look for agents that kill cancer stem cells. [lien] [EN]