How stem cells make skinSeptember 14, 2009EMBL scientists come a step closer to understanding skin, breast and other cancers Stem cells have a unique ability: when they divide, they can either give rise to more stem cells, or to a variety of specialised cell types. In both mice and humans, a layer of cells at the base of the skin contains stem cells that can develop into the specialised cells in the layers above. Scientists at the European Molecular Biology Laboratory (EMBL) in Monterotondo, in collaboration with colleagues at the Centro de Investigaciones Energéticas, Medioambientales y Tecnologicas (CIEMAT) in Madrid, have discovered two proteins that control when and how these stem cells switch to being skin cells. The findings, published online today in Nature Cell Biology, shed light on the basic mechanisms involved not only in formation of skin, but also on skin cancer and other epithelial cancers. At some point in their lives, the stem cells at the base of the skin stop proliferating and start differentiating into the cells that form the skin itself. To do so, they must turn off the 'stem cell programme' in their genes and turn on the 'skin cell programme'. Researchers suspected that a family of proteins called C/EBPs might be involved in this process, as they were known to regulate it in other types of stem cell, but had so far failed to identify which C/EBP protein controlled the switch in skin. Claus Nerlov and his group at EMBL Monterotondo discovered it was not one protein, but two: C/EBPα and C/EBPβ. The EMBL researchers used genetic engineering techniques to delete the genes that encode C/EBPα and β specifically in the skin of mouse embryos, and found that without these proteins the skin of the mice did not form properly. "Mice with neither C/EBPα nor β had taut and shiny skin that couldn't keep the water inside their bodies", Nerlov explains, "they lacked many of the proteins that make skin mechanically strong and water tight, and they died of de-hydration shortly after birth". However, a single working copy of either the gene for C/EBPα or the gene for C/EBPβ was enough to ensure that skin developed properly. This means that the two proteins normally do the same job in the skin's stem cells - an unexpected redundancy, which may have arisen because there are so many stem cells in skin that a tight control on proliferation is needed to avoid problems like cancer. Or it may simply be a by-product of the fact that these two proteins have different functions in other situations, such as wound healing or repair of sunlight-induced skin damage. One of the hallmarks of epithelial cancers - which include skin, breast, and oral cancers - is that they have genes turned on which would normally only be expressed in embryonic stem cells, and which may help cancer cells divide indefinitely. Such genes become re-expressed in the skin in the absence of C/EBPs. So, by understanding how C/EBPα and β turn off such 'stem cell' programmes, researchers hope to come a step closer to finding ways to fight such cancers. When Nerlov and colleagues looked at how C/EBPα and -β work in the skin, they found that these proteins also regulate a number of other molecules that control skin development. Several important pathways known to control skin and hair formation were improperly activated in the mice lacking C/EBPα and -β. "This is a very important discovery", says Nerlov. "It opens up a lot of new areas, because we can see how these proteins control virtually every other molecule known to regulate skin cell differentiation. It seems to be a key piece in the puzzle of how our skin is formed and maintained throughout life." European Molecular Biology Laboratory |
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| Related Stem Cells Current Events and Stem Cells News Articles Chemists influence stem-cell development with geometry University of Chicago scientists have successfully used geometrically patterned surfaces to influence the development of stem cells. The new approach is a departure from that of many stem-cell biologists, who focus instead on uncovering the role of proteins in controlling the fate of stem cells. Amniotic fluid cells more efficiently reprogrammed to pluripotency than adult cells In a breakthrough that may help fill a critical need in stem cell research and patient care, researchers at Mount Sinai School of Medicine have demonstrated that skin cells found in human amniotic fluid can be efficiently "reprogrammed" to pluripotency, where they have characteristics similar to human embryonic stem cells that can develop into almost any type of cell in the human body. UC Irvine biologists help sequence Hydra genome UC Irvine researchers have played a leading role in the genome sequencing of Hydra, a freshwater polyp that has been a staple of biological research for 300 years. Researchers characterize stem cell function The promise of stem cells lies in their unique ability to differentiate into a multitude of different types of cells. But in order to determine how to use stem cells for new therapeutics, scientists and engineers need to answer a fundamental question: if a stem cell changes to look like a certain type of cell, how do we know if it will behave like a certain type of cell? Novel stroke treatment passes safety stage of UCI-led clinical trial A clinical research trial of a new treatment to restore brain cells damaged by stroke has passed an important safety stage, according to the UC Irvine neurologist who led the effort. Model may offer better understanding of embryonic development A mathematical model developed at Purdue University can predict complex signaling patterns that could help scientists determine how stem cells in an embryo later become specific tissues, knowledge that could be used to understand and treat developmental disorders and some diseases. University of Michigan scientists discover bone marrow can harbor HIV-infected cells University of Michigan scientists have identified a new reservoir for hidden HIV-infected cells that can serve as a factory for new infections. Repeated anesthesia can affect childrens ability to learn There is a link between repeated anaesthesia in children and memory impairment, though physical activity can help to form new cells that improve memory, reveals new research from the Sahlgrenska Academy at the University of Gothenburg, Sweden. A new indicator of poor prognosis in node-negative colorectal cancer patients Tumor budding at the invasive tumor front of colorectal cancer is recognized as an independent prognostic factor significantly related to both lymph node and distant metastasis. Breakthrough reveals blood vessel cells are key to growing unlimited amounts of adult stem cells In a leap toward making stem cell therapy widely available, researchers at the Ansary Stem Cell Institute at Weill Cornell Medical College have discovered that endothelial cells, the most basic building blocks of the vascular system, produce growth factors that can grow copious amounts of adult stem cells and their progeny over the course of weeks. More Stem Cells Current Events and Stem Cells News Articles |
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