The Research

A drug treatment that mimics fasting can also provide the same benefit, study finds.... Intestinal stem cells from mice that fasted for 24 hours, at right, produced much more substantial intestinal organoids than stem cells from mice that did not fast, at left. Credit: Maria Mihaylova and Chia-Wei Cheng     A s people age, their intestinal stem cells begin to lose their ability to regenerate. These stem cells are the source for all new intestinal cells, so this decline can make it more difficult to recover from gastrointestinal infections or other conditions that affect the intestine. In fasting mice, cells begin breaking down fatty acids instead of glucose, a change that stimulates the stem cells to become more regenerative. The researchers found that they could also boost regeneration with a molecule that activates the same metabolic switch. Such an intervention could potentially help older people recovering from GI infections or cancer patients undergoing chemot...

T umor cells use the unfolded protein response to alter circadian rhythm, which contributes to more tumor growth, Hollings Cancer Center researchers at the Medical University of South Carolina (MUSC) find. A key part of the circadian clock opposes this process, according to a paper published online Dec. 11 in Nature Cell Biology. For tumors to grow and spread, cancer cells must make larger than normal amounts of nucleic acids and protein, so they can replicate themselves. Yet in both normal and cancer cells that increase their synthesis of protein, a small percent of those proteins do not fold properly. When that happens, the cell activates its unfolded protein response (UPR), which slows down the making of new proteins while the misfolded proteins are refolded. Eventually, the buildup of misfolded proteins becomes toxic and leads to cell death. However, cancer cells have learned to use the UPR to slow protein synthesis when needed, in order to handle the backlog of misfolded pro...

University of California, Berkeley scientists have for the first time used CRISPR-Cas9 gene editing to disable a defective gene that causes amyotrophic lateral sclerosis, or Lou Gehrig’s disease, in mice, extending their lifespan by 25 percent. The therapy delayed the onset of the muscle wasting that characterizes the disease, which results in progressive weakness and eventually proves fatal when the muscles that control breathing fail. This step toward a CRISPR cure for human ALS will be reported Dec. 20 in the journal  Science Advances. The mice were genetically engineered to express a mutated human gene that in humans causes about 20 percent of all inherited forms of the disease and about 2 percent of all cases of ALS worldwide. Though the genetic cause is not known for all cases of ALS, all are accompanied by the premature death of motor neurons in the brain stem and spinal cord. The neurons allow the brain to control muscles, so loss of this connection means loss of...