Exercise-related hormone irisin found to target key bone cells
Scientists have discovered that irisin, a hormone released by muscles during exercise, directly acts on key regulatory cells that control the breakdown and formation of bone. The researchers say this insight raises the prospect of new treatments for bone-thinning disorders such as osteoporosis. Reporting in Cell, Bruce Spiegelman and colleagues at Dana-Farber Cancer Institute say they have for the first time identified a molecular receptor for irisin, which Spiegelman discovered in 2012. The receptor allows irisin to bind to and activate osteocytes, the most abundant cell type in adult human bone. Spiegelman, the Stanley J. Korsmeyer Professor of Cell Biology and Medicine at Harvard Medical School, and others have proposed that the irisin hormone serves as a link between exercise and its beneficial effects on health, including burning fat, strengthening bones, and protecting against neurodegenerative diseases. Until now, however, researchers hadn’t identified a specific molecular receptor for irisin — in effect, a docking structure allowing irisin to...