Researchers at the The Scripps Research Institute found a new way of classifying the many cell types that fall under the category of "stem cells." The term stem cell refers to tissue specific stem cells found in mature tissues such as blood, brain, or muscle, which are restricted to forming only cells found in those tissues, as well as to embryonic stem cells that are broadly able to form all cells of the body.
Researchers at UC, Irvine identified the true location of adult stem cells in the brain. Previous studies indicated that in mammals, adult neural stem cells originate in a region of the brain called the subventricular zone. In this study, the team found evidence that stem cells exist only in a region called the ependymal layer, which is adjacent to the subventricular zone. They also coaxed the ependymal stem cells to divide in adult rats displaying Parkinson's Disease-like symptoms.
Researchers at the Salk Institute of Biological Studies discovered that stem cells in the testes of fruit flies are able to generate their own support cells. This work in flies could help guide researchers hoping to understand the environment surrounding resident populations of human stem cells - called the niche. The niche is difficult to study in humans but is an area of great interest because any therapy based on transplanting stem cells into a tissue will require those cells to be paced in a niche where they will thrive.
Researchers at UC, Berkeley identified a signaling molecule that interferes with the ability of older skeletal muscle to regenerate. After injury, adult skeletal muscle regenerates by activating muscle stem cells that fuse with the existing muscle cells to repair the damage. This ability to regenerate diminishes with age, not because of a decline in the number of resident stem cells, but because stem cells in the older muscle don't respond when damage occurs. It turns out that older muscles release molecules that actively inhibit the resident stem cells.
Researchers at UC, Los Angeles discovered a series of mutations that can convert normal blood stem cells into cancer stem cells. It is believed that many types of cancer result from cancer stem cells created by such mutations. In this case the first mutation converted normal stem cells and then caused over expression of an oncogene, a cancer gene, resulting in a proliferation of leukemia stem cells and acute T-cell lymphoblastic leukemia in a mouse model.
Researchers at The Scripps Research Institute discovered that human embryonic stem cells have a very specific signature when it comes to the regulators of their genes. MicroRNAs are very small, naturally occurring bits of genetic material. They don't code for specific proteins like genes do, but they regulate the activity of genes and turn on and off their protein production.
Researchers at the Burnham Institute for Medical Research have developed a new way of quickly maturing embryonic stem cells into neural cells. Other research groups have worked out lab conditions that encourage embryonic stem cells to mature into various types of nerve cells, but those methods were slow and resulted in early stage nerve cells that were more likely to cause tumors when transplanted into mice. This new method could speed work by researchers who are trying to develop therapies for diseases of the nervous system.
Researchers at the Gladstone Institute for Cardiovascular Disease discovered how two specific tiny genetic factors called microRNAs influence the differentiation of embryonic stem cells into heart muscle. They found that the factors not only drive the versatile cells to become heart, but also actively prevent them from becoming other tissue such as bone adding to their potential to make therapy more specific and targeted for patients.
Cell Stem Cell: March 6, 2008
Researchers at UC, Los Angeles succeeded in inducing skin cells to become pluripotent cells with genetic featured very much like embryonic stem cells. They verified work published during the completion of their project, which showed that the introduction of four specific genetic factors is sufficient to induce differentiated adult cells into reverting to an embryonic stem cell-like state. This was critical validation of a procedure that could lead to a new way of developing personalized cell lines for therapy.
Researchers at UC, Irvine used mouse embryonic stem cells to demonstrate that a specific mutation can cause cardiomyopathy, with a thickened heart wall, in the mouse. The team looked at the small DNA molecule located outside of the nucleus, so-called mitochondrial DNA, which we all inherit exclusively from our mothers. They also discovered that severe mutations in this mitochondrial DNA are readily eliminated from the mouse germ line in just four generations. They expect the method they used to become a robust research tool to study the impact of mutations on stem cells.