Osteoporosis is a disease where loss of bone tissue leads to increased risk of fracture at loads that would not normally be traumatic. It is a major health risk for 44 million Americans, 68% of whom are women. One out of every two women and one out or every four men over the age of 50 are predicted to experience an osteoporotic fracture in their lifetimes. Hip fractures are particularly debilitating often leading to loss of independence, institutionalization, and mortality with up to 30% of patients dying in the first year post-fracture. In fact, more women die of osteoporosis than breast cancer. National direct expenditures are estimated to be $14 billion annually and are predicted to reach $240 billion by 2040.
Osteoporosis occurs when stem cells in the bone marrow no longer supply new bone forming cells in sufficient numbers. One of the known factors that regulates the creation of new bone cells is physical loading of the skeleton. However, virtually nothing is known about how stem cells sense their mechanical environment. A novel cellular antenna-like structure, the primary cilium, has been shown in our lab to act as just such a mechanical sensor in bone cells. The focus of this project will be to determine if primary cilia act as mechanical sensors in stem cells.