Scientists discover new, readily available source of stem cells

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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 discover human embryonic stem cells are the ultimate perpetual fuel cell

A startling discovery on the development of human embryonic stem cells by scientists at McMaster University will change how future research in the area is done. An article published in the prestigious scientific journal Nature this week reports on a new understanding of the growth of human stem cells. It had been thought previously that stem cells are directly influenced by cells in the local environment or ‘niche', but the situation may be more complex. Human embryonic stem cells are perpetual machines that generate fuel for life. In this week's Nature, researchers of the McMaster Cancer and Stem Cell Research Institute show that human embryonic stem (ES) cells can actually produce distinctive niche cells. [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]

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 new class of RNA

The last few years have been very good to ribonucleic acid (RNA). Decades after DNA took biology by storm, RNA was considered little more than a link in a chain–no doubt a necessary link, but one that, by itself, had little to offer. But with the discoveries of RNA interference and microRNAs, this meager molecule has been catapulted to stardom as a major player in genomic activity. Now, a team of scientists led by David Bartel, a professor in MIT’s Department of Biology, has discovered an entirely new class of RNA molecules. Reporting in the journal Cell, the team describes identifying more than 5,000 of these new molecules, termed 21U-RNAs, in the C. elegans worm. These new RNAs are named after their distinctive features: Each molecule contains 21 chemical building blocks (or nucleotides). [lien] [EN]

Scientists find previously unknown receptors on adult stem cells

For many years, researchers believed that stem cells in the bone marrow spent most of their existence in a slumber-like state, unaware of — and unaffected by — the daily battles fought by the body's immune system. Not so. Scientists at the Oklahoma Medical Research Foundation have discovered that marrow stem cells — undifferentiated cells that eventually give rise to the blood cells that fight infection — possess receptors that recognize bacteria and viruses. When activated, these receptors kick the stem cells and immature blood cells into action, enlisting them to help fight whatever pathogen is attacking the body. The findings, which appear in the June issue of the journal Immunity, could have important implications for treating leukemias and autoimmune diseases such as lupus and rheumatoid arthritis. [lien] [EN]

Scientists eliminate viral vector in stem cell reprogramming

Previously, Dr. Shinya Yamanaka of Kyoto University and the Gladstone Institute of Cardiovascular Disease, had shown that adult cells can be reprogrammed to become embryonic stem cell–like using a cancer-causing oncogene as one of the four genes required to reprogram the cells, and a virus to transfer the genes into the cells. In the last year, Dr. Yamanaka and other labs showed that the oncogene, c-Myc, is not needed. However the use of viruses that integrate into the genome prohibit use of iPS cells for regenerative medicine because of safety concerns: its integration into the cell’s genome might activate or inactivate critical host genes. Now Dr. Yamanaka’s laboratory in Kyoto has eliminated the need for the virus. In a report published this week in Science. [lien] [EN]

Scientists discover new genetic immune disorder in children

Your immune system plays an important function in your health—it protects you against viruses, bacteria, and other toxins that can cause disease. In autoinflammatory diseases, however, the immune system goes awry, causing unprovoked and dangerous inflammation. Now, researchers from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), part of the National Institutes of Health, and other institutions have discovered a new autoinflammatory syndrome, a rare genetic condition that affects children around the time of birth. The findings appear in the current issue of the New England Journal of Medicine. The scientists have termed the new autoinflammatory syndrome DIRA (deficiency of the interleukin1 receptor antagonist). Children with the disorder display a constellation of serious and potentially fatal symptoms that include swelling of bone tissue. [lien] [EN]

Scientists discover new gene that prevents multiple types of cancer

A decades-old cancer mystery has been solved by researchers at Cold Spring Harbor Laboratory (CSHL). “We not only found a critical tumor suppressor gene, but have revealed a master switch for a tumor suppressive network that means more targeted and effective cancer therapy in the future,” said CSHL Associate Professor Alea Mills, Ph.D. The study was published in the February issue of Cell. Caption: The Mills group altered normal cells so that they had one extra- (left) or one fewer- (right) copies of a chromosome segment representing human 1p36 than normal cells; this caused added tumor suppression and increased cancer, respectively. Credit: Cold Spring Harbor Laboratory Specifically, Mills’ discovery identifies CHD5, a protein that prevents cancer, as a novel tumor suppressor. [lien] [EN]

Scientists develop new procedure to differentiate human embryonic stem cells

Scientists have developed a new procedure for the differentiation of human embryonic stem cells, with which they have created the first transplantable source of lung epithelial cells. The method involves the use of protein markers under the control of cell-specific promoters to convert undifferentiated human embryonic stem cells into highly-specialized cells. The human embryonic stem cells were cultured on specially coated dishes and transfected with a lung epithelial gene regulator of a drug selection gene. The process, created in the laboratory of Rick A. Wetsel, Ph.D., a professor of molecular medicine at the Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases (IMM), is described in this week's edition of the Proceedings of the National Academy of Sciences (PNAS). [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 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]

Neural stem cell differentiation factor discovered

Neural stem cells represent the cellular backup of our brain. These cells are capable of self-renewal to form new stem cells or differentiate into neurons, astrocytes or oligodendrocytes. Astrocytes have supportive functions in the environment of neurons, while oligodendrocytes form the myelin layer around axons in order to accelerate neuronal signal transmission. But how does a neural stem cell „know” which way it is supposed to develop? On the molecular level receptors of the Notch family play a significant role in this process. So far, only stimulating extracellular ligands of Notch receptors had been described. Biochemists of Goethe University Medical School now describe a long time assumed but not yet identified soluble Notch inhibitor. Franfurt scientists led by Mirko Schmidt and Ivan Dikic reported in the renowned journal „Nature Cell Biology” that the secreted protein EGFL7 (Epidermal Growth Factor. [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]