Cell Conversions A revolutionary technique converts one type of adult cell into another.
Making Insulin: Pancreatic cells that have been reprogrammed to turn into insulin-¬producing beta cells, the cell type lost in type 1 diabetes, produce the growth factor VEGF (blue) and insulin (red and pink). Cell nuclei are marked in green.
Source: “In vivo reprogramming of adult pancreatic exocrine cells to beta-cells” Douglas Melton et al. Nature,published online August 27, 2008
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Results: By activating a specific set of genes in mice, scientists at the Harvard Stem Cell Institute converted a common type of pancreatic cell into a rarer, insulin-producing one. The research is the first to show that one type of fully formed adult cell can be directly converted into another type.
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Why it matters: The technique might ultimately provide a way to replace the cells lost in diabetes and other diseases, such as Parkinson’s and amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease). The findings also open a new avenue of research in regenerative medicine–a field in which researchers develop therapies to repair or replace damaged cells and tissue. The technique provides an alternative to generating specific cell types from stem cells and transplanting them. Instead, scientists may be able to grow specialized cells directly from existing tissue in the body.
Methods: The researchers first identified a set of ninegenes that trigger the activity of other genes in pancreatic beta cells. Then they genetically engineered mature exocrine cells, which make up about 95 percent of the pancreas, to express combinations of the nine proteins, called transcription factors, that the genes produce. Eventually, they found a combination of three that transformed the exocrine cells into insulin-producing beta cells.
Next steps: Scientists at Harvard are now trying to repeat the results with human cells. Others are trying a similar approach with different cell types, such as the motor neurons lost in ALS.
Better Diagnoses Different diseases show specific microRNA profiles in the blood.
Source: “Characterization of microRNAs in serum: a novel class of biomarkers for diagnosis of cancer and other diseases” Chen-Yu Zhang et al. Cell Research, published online September 2, 2008
Results: Scientists at Nanjing University in China found that patients with lung cancer, colorectal cancer, and diabetes had characteristic patterns of microRNA circulating in their blood. Each disease was associated with a unique pattern that differed from those seen in healthy people.
Why it matters: The findings provide the basis for a type of diagnostic test that could be more accurate than those currently available. MicroRNAs are small RNA molecules that do not code for proteins but help control protein synthesis. Previous work had shown that they could play some role in cancer. But the new research is the first to find specific microRNA patterns that might be useful for diagnosis. MicroRNAs could also help doctors predict a disease’s progression and evaluate a patient’s responses to treatment. In addition, the study shows that microRNAs might have diagnostic potential for other diseases, such as diabetes.
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Methods: Scientists used gene-sequencing technology to identify the type and levels of microRNAs in the blood serum of healthy people and people with lung cancer, colorectal cancer, and diabetes.
Next steps: The researchers are now developing the first commercial diagnostic kit based on measurement of microRNA in blood serum. They aim to release it next year. They are also trying to understand the function of microRNAs in the blood.
