Exercise's link to osteoporosis protection involves Piezo1, study reports

Researchers report that the protein Piezo1 acts as a mechanical 'exercise sensor' in bone marrow stem cells and promotes bone formation in mice; removing Piezo1 reduced bone density and increased marrow fat, and the findings come from mouse studies rather than human trials.

Researchers led by the University of Hong Kong report that a protein called Piezo1 functions as an 'exercise sensor' in bone marrow cells and helps shift cells toward bone formation. The team examined bone marrow mesenchymal stem cells (BMMSCs), which can become osteoblasts (bone-forming cells) or adipocytes (fat cells). They found that mechanical forces activate Piezo1, promoting bone growth and reducing marrow fat in mouse models. The study was published in Signal Transduction and Targeted Therapy. Key findings: - Piezo1 senses mechanical strain and, when active, promotes bone formation and reduces fat accumulation in bone marrow in mice. - Deleting Piezo1 in mouse cells led to lower bone density, less bone formation, and more marrow adipocytes. - Mice lacking Piezo1 did not receive the usual bone-strengthening effects of exercise. - The researchers identified signaling pathways downstream of Piezo1 and showed that restoring Piezo1 activity or its downstream effects could reverse the observed changes. - All experiments reported were carried out in mouse models; the effects in humans have not been established. Summary: The study clarifies a molecular route by which mechanical forces influence BMMSC fate and bone strength, centered on the Piezo1 protein. It identifies a potential target for treatments that might mimic some biological effects of exercise, but the work is preclinical and additional research is needed to determine safety and relevance in humans.