Acute nutrient ingestion leads to a rapid inhibition of bone resorption while effects on makers of bone formation are less marked or absent, suggesting that there is a transient shift toward skeletal accretion in the immediate postprandial period. The cellular bases for these effects are not clear. Glucose-dependent insulinotropic peptide (GIP), a known modulator of glucose-induced insulin secr...

The EphB4 receptor and ephrin B2 ligand were recently reported to influence the coupling between osteoclasts and osteoblasts in bone biology, but their downstream signaling pathways remain unclear. This study focuses on the preliminary identification of downstream PDZ-domain proteins involved in EphB4/ephrin B2 reverse signaling in osteoclasts. Similarly to primary osteoclast precursors isolate...

Osteoclasts are the sole bone resorbing cells. Heightened activity of these cells under pathological conditions leads to the development of bone loss diseases, such as osteolysis, osteoporosis and rheumatoid arthritis. We have shown previously that TNF strongly induces osteoclastogenesis of pre-osteoclasts and do so through activation of the transcription factor, NF-κB. Most importantly, recent...

In human prostate to bone metastases and in a novel rodent model that recapitulates prostate tumor-induced osteolytic and osteogenic responses, we found that osteoclasts are a major source of the proteinase, matrix metalloproteinase (MMP)-9. Because MMPs are important mediators of tumor-host communication, we tested the effect of host-derived MMP-9 on prostate tumor progression in the bone. To ...

STATEMENT OF THE PROBLEM Various researchers have suggested the use of β2-adrenergic receptor antagonists in prevention or treatment of bone resorption. PURPOSE This study aimed to evaluate the effect of β2-adrenergic receptor antagonists on number of osteoclasts and osteoblasts involved in the healing of extraction socket of maxillary first molar in rats. MATERIALS AND METHOD Maxillary fir...

Myeloid differentiation factor 88 (MyD88) plays essential roles in the signaling of the Toll/interleukin (IL)-1 receptor family. Toll-IL-1 receptor domain-containing adaptor inducing interferon-beta (TRIF)-mediated signals are involved in lipopolysaccharide (LPS)-induced MyD88-independent pathways. Using MyD88-deficient (MyD88-/-) mice and TRIF-deficient (TRIF-/-) mice, we examined roles of MyD...

Osteoclasts are highly specialized cells that are derived from the monocyte/macrophage lineage of the bone marrow. Their unique ability to resorb both the organic and inorganic matrices of bone means that they play a key role in regulating skeletal remodeling. Together, osteoblasts and osteoclasts are responsible for the dynamic coupling process that involves both bone resorption and bone forma...

BACKGROUND Increased reactive oxygen species and estrogen deficiency contribute to the pathophysiology of postmenopausal osteoporosis. Reactive oxygen species contribute to bone degradation and is necessary for RANKL-induced osteoclast differentiation. In postmenopausal bone loss, reactive oxygen species can also activate immune cells to further enhance bone resorption. Here, we investigated th...

It is well established that activation of Wnt/βcatenin signaling in the osteoblast lineage leads to an increase in bone mass through a dual mechanism: increased osteoblastogenesis and decreased osteoclastogenesis. However, the effect of this pathway on the osteoclast lineage has been less explored. Here, we aimed to examine the effects of Wnt/βcatenin signaling in mature osteoclasts by generati...

Osteoclasts are large, multinucleated cells, which originate from the fusion of macrophages. They play a central role in bone development and remodeling via the resorption of bone and are thus important mediators of bone loss, which leads to osteoporosis. IL-1R-associated kinase (IRAK)-M is a pseudokinase, which acts as a negative modulator of innate immune responses mediated by TLRs and IL-1R....