Published in Nature's early online edition, researchers at Children's Hospital Boston have used stem cells to study why cancer appears less in people with Down syndrome. Following up on previous studies, they found that one gene on chromosome 21, DSCR1, is increased in expression in Down's syndrome tissues and in a mouse model of Down's syndrome. DSCR1, Down's syndrome candidate region-1, encodes a protein that suppresses angiogenesis by the calcineurin pathway. Next, when they injected normal human iPS cells into mice with compromised immune systems, they caused tumor growth, but when they injected iPS cells derived from patients with Down syndrome, the tumors formed hardly any blood vessels at all, says a story at Technology Review.
This week in Nature, work out of Peter Sorger's lab at Harvard looks at how individual cells respond in a population when it comes to apoptosis. To measure the difference in TRAIL-induced apoptosis between different cells in a population, they imaged sister cells with reporters of caspase activation and mitochondrial outer membrane permeabilization after exposure to TRAIL and found that some cells die while others do not. They attribute this to a random difference in natural protein expression. "[Their] work for the first time relates variability in molecular processes determined by protein-expression levels to variability in phenotypic response in human cells," says a News and Views piece.
In Nature Medicine this week, Philip Johnson, a professor of pediatrics at the University of Pennsylvania, led work that used a vector to introduce antibody-like molecules into monkeys that protected them from infection by SIV, or simian immunodeficiency virus, reports another story in Tech Review. After engineering immunoadhesin sequences into the adeno-associated virus vectors and injecting them into the muscles of nine rhesus macaques, the monkeys produced the new antibodies and protected the majority of them from infection over the course of a year. "This has given us a really big green light in the monkey model, but of course we still need to show this also works in humans," says Johnson.
There's a series of articles in Nature Genetics this week associating various genes to menarche, or onset of menstruation, and menopause. In one, a meta-analysis of GWAS from 17,510 women found loci at chromosome 9q31.2 and the gene LIN28B associated with age at menarche. A related study explores LIN28B further. Another GWAS found three chromosomes associated with age at menopause in European woman: 19q13.4, 20p12.3, and 13q34. Related studies from Chunyan He at Harvard, and Decode's Kari Stefansson and Patrick Sulem find even more associations.