study about health 23

The mammary gland is composed two main cellular subtypes: the basal cells and luminal cells. While luminal cells secrete water and nutriments to produce the milk during lactation, the basal cells, through their contraction, guide the circulation of the milk throughout the ductal tree. Luminal cells can be subdivided into estrogen (ER)/progesterone (PR) positive and negative cells. In this study published in  Cell Reports , Alexandra Van Keymeulen and colleagues generated a new transgenic line-allowing lineage tracing of ER+ luminal cells to investigate luminal cell heterogeneity and identify the origin of ER+ luminal cells and the mechanisms regulating their pubertal expansion and adult maintenance. Surprisingly and in sharp contrast with the common thought, which hypothesized the existence of a population of common progenitors that give rise to ER+ and ER- cells, Alexandra Van Keymeulen and colleagues found that the ER+ lineage is maintained by a lineage restricted ER+ luminal

Hans-Reimer Rodewald, a scientist at the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) in Heidelberg, and his co-workers wanted to capture the dynamic events in blood cell formation instead of merely taking snapshots. In close collaboration with a research team led by systems biologist Thomas Höfer, the scientists have developed a new technology that enables them to precisely follow the developmental tracks of cells. To this end, they label stem cells with a kind of genetic barcode in order to be able to clearly identify their offspring later. "Genetic barcodes have been developed and applied before, but they were based on methods that can also change cellular properties," Rodewald said. " Our barcodes are different: They can be induced tissue-specifically and directly in the genome of mice -- without influencing the animals' physiological development." The basis of the new technology is the so-called Cre/loxP system that is used t

Certain genetic changes are known to reduce the ability of an enzyme called TET2 to encourage stem cells to become mature blood cells, which eventually die, in many patients with certain kinds of leukemia, say the authors. The new study found that vitamin C activated TET2 function in mice engineered to be deficient in the enzyme. "We're excited by the prospect that high-dose vitamin C might become a safe treatment for blood diseases caused by TET2-deficient leukemia stem cells, most likely in combination with other targeted therapies," says corresponding study author Benjamin G. Neel, MD, PhD, professor in the Department of Medicine and director of the Perlmutter Cancer Center. Changes in the genetic code (mutations) that reduce TET2 function are found in 10 percent of patients with acute myeloid leukemia (AML), 30 percent of those with a form of pre-leukemia called myelodysplastic syndrome, and in nearly 50 percent of patients with chronic myelomonocytic leukemia

We have known for a while that people with lower levels of ascorbate (vitamin C) are at increased cancer risk, but we haven't fully understood why. Our research provides part of the explanation, at least for the blood-forming system," said Dr. Sean Morrison, the Director of CRI. The metabolism of stem cells has historically been difficult to study because a large number of cells are required for metabolic analysis, while stem cells in each tissue of the body are rare. Techniques developed during the study, which was published in  Nature , have allowed researchers to routinely measure metabolite levels in rare cell populations such as stem cells. The techniques led researchers to discover that every type of blood-forming cell in the bone marrow had distinct metabolic signatures -- taking up and using nutrients in their own individual way. One of the main metabolic features of stem cells is that they soak up unusually high levels of ascorbate. To determine if ascorbate is