title: Regulatory pathways revealing new approaches to the development of anabolic drugs for osteoporosis.
abstract: The understanding of cell interactions and genetic controls of bone cells has provided new approaches to drug development for osteoporosis. Current emphasis in the development of new anabolic therapies is directed at modifying the effects of Wnt signalling on osteoblast differentiation and bone formation. Local signalling that results in bone formation during remodelling takes place in several ways. Growth factors released from resorbed bone matrix can contribute to preosteoblast differentiation and bone formation. Osteoclasts in the bone multicellular units (BMUs) might also generate activity that contributes to bone formation. The preosteoblasts themselves, growing in the resorption space, can communicate through cell contact and paracrine signalling mechanisms to differentiate. Osteocytes can sense the need for bone repair by detecting damage and pressure changes, and signalling to surface cells to respond appropriately. These recent insights into cell communication, together with discoveries from human and mouse genetics, have opened new pathways to drug development for osteoporosis. With the anabolic effect of parathyroid hormone on the skeleton having been established, human genetics revealed the major role of Wnt signalling in bone formation, and this has become the target of activity. Current approaches include activation at any of several points in the Wnt pathway, and neutralization of sclerostin, the protein product of the SOST gene that is produced in osteocytes as a powerful inhibitor of bone formation.
authors.affiliation: St Vincent's Institute of Medical Research, Melbourne, Australia. jmartin@svi.edu.au
authors.forename: T J
authors.initials: TJ
authors.lastname: Martin
authors.forename: N A
authors.initials: NA
authors.lastname: Sims
authors.forename: K W
authors.initials: KW
authors.lastname: Ng
mesh_terms: D045930:Anabolic Agents / Q000627:therapeutic use*; D016723:Bone Remodeling / Q000187:drug effects; D006801:Humans; D010006:Osteoblasts / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects; D010024:Osteoporosis / Q000188:drug therapy* / Q000503:physiopathology; D010281:Parathyroid Hormone / Q000627:therapeutic use; D015398:Signal Transduction / Q000187:drug effects; D051153:Wnt Proteins / Q000502:physiology
chemical_list: D045930:Anabolic Agents; D010281:Parathyroid Hormone; D051153:Wnt Proteins