Bone Abstracts

Wnt signaling is a major regulator of bone metabolism. We recently reported that mutations in WNT1 gene in humans cause early onset osteoporosis and severe osteogenesis imperfecta. To identify the cellular source and the mechanisms causing these severe phenotypes we generated and analyzed global and conditional Wnt1 knockout mice.Heterozygous Wnt1+/− mice were viable and fertile but Wnt1−/− embryos were lost in ute...

Osteoporosis is a frequent disease leading to an increased risk of fractures caused by a systemic impairment of bone mass, strength, and microarchitecture. Given the emerging role of the Wnt signaling pathway in bone biology, we focused on the function of the important Wnt inhibitor dickkopf-1 (Dkk-1) and examined how the deletion of Dkk-1 solely in osteoblasts or osteocytes influences bone homeostasis. Therefore, we used the Cre-LoxP recombination system and crossed Dkk-1-flo...

Introduction: Bone mineral density (BMD) is a highly heritable trait used to assess skeletal health in children and risk of osteoporosis later in life. To date >60 loci associated with bone-related traits measured at different skeletal sites have been identified. We conducted a genome-wide association study (GWAS) meta-analysis of total body (TB-)BMD in children and adults to identify genetic determinants and age-specific effects of loci on this trait.<p class="abstext...

Loss of the gene encoding the secreted Wnt antagonist sclerostin results in increased bone mass in humans and mice. Administration of antibodies to sclerostin (Scl-Ab) has been shown to increase bone mineral density (BMD) by increasing bone formation and decreasing bone resorption, in both animal studies and human clinical trials. In these studies, the magnitude and rate of increase in bone formation markers, and the rate of increase of BMD, diminishes upon repeat dosing with ...

Mechanosenstitive osteocytes in bone supress the local production of sclerostin in response to mechanical loading, to increase osteoblast differentiation and bone mass. In addition, sclerostin is secreted from osteocytes into the circulation. Serum sclerostin has been shown to correlate with osteoporosis and low bone mass, however there is limited evidence by which to determine whether serum sclerostin is acting either a biomark...

We have shown that genetic ablation of Cdh2 (N−cadherin gene) in osteolineage cells results in osteopenia and decreased osteoprogenitor number. Paradoxically, others have shown that mice overexpressing Cdh2 in osteoblasts are also osteopenic; an action linked to a negative effect of N−cadherin (Ncad) on Wnt signaling, via sequestration of low density lipoprotein receptor−related protein−...