Osteoclasts, the only cells with bone resorption functions in vivo, maintain the balance of bone metabolism by cooperating with osteoblasts, which are responsible for bone formation. Excessive activity of osteoclasts causes many diseases such as osteoporosis, periprosthetic osteolysis, bone tumors, and Paget's disease. In contrast, osteopetrosis results from osteoclast deficiency. Available str...

Gene expressionis controlled by epigenetic mechanisms including histone methylation. Osteoclasts are bone-resorptive cells that differentiate from hematopoietic-precursor cells by receptor activator of nuclear factor-κB ligand (RANKL) stimulation. Although BIX01294, a specific inhibitor of G9a, which works as a histone H3 lysine 9 (H3K9) methyltransferase, reportedly changes cellular differenti...

Multinucleated osteoclasts differentiate from hematopoietic progenitors of the monocyte/macrophage lineage. Because of its pivotal role in bone resorption, regulation of osteoclast differentiation is a potential therapeutic approach to the treatment of erosive bone disease. In this study, we have found that fucoidan, a sulfated polysaccharide extracted from brown seaweed, inhibited osteoclast d...

Multiple myeloma is characterized by the clonal expansion of malignant plasma cells (multiple myeloma cells [MMCs]), in the bone marrow. Osteolytic bone lesions are detected in 80% of patients because of increased osteoclastic bone resorption and reduced osteoblastic bone formation. MMCs are found closely associated with sites of increased bone resorption. Osteoclasts strongly support MMC survi...

PTH is an anabolic agent used to treat osteoporosis, but its mechanisms of action are unclear. This study elucidated target cells and mechanisms for anabolic actions of PTH in mice during bone growth. Mice with c-fos ablation are osteopetrotic and lack an anabolic response to PTH. In this study, there were no alterations in PTH-regulated osteoblast differentiation or proliferation in vitro in c...

Osteoclasts mediate the process of bone resorption. However, little is known about the mechanisms that regulate the formation of either osteoclasts or osteoclast precursors. In contrast, colonystimulating factors (CSFs) are well-known to regulate the formation of myeloid cells and their precursors. Because osteoclasts and myeloid cells may originate from a common stem cell, we examined the effe...

A2B adenosine receptor (A2BAR) is known to be the regulator of bone homeostasis, but its regulatory mechanisms in osteoclast formation are less well-defined. Here, we demonstrate the effect of A2BAR stimulation on osteoclast differentiation and activity by RANKL. A2BAR was expressed in bone marrow-derived monocyte/macrophage (BMM) and RANKL increased A2BAR expression during osteoclastogenesis. ...

BACKGROUND Osteoclasts and osteoblasts regulate bone resorption and formation to allow bone remodeling and homeostasis. The balance between bone resorption and formation is disturbed by abnormal recruitment of osteoclasts. Osteoclast differentiation is dependent on the receptor activator of nuclear factor NF-kappa B (RANK) ligand (RANKL) as well as the macrophage colony-stimulating factor (M-CS...

Long-term administration of glucocorticoids (GCs) causes osteoporosis with a rapid and severe bone loss and with a slow and prolonged bone disruption. Although the involvement of GCs in osteoblastic proliferation and differentiation has been studied extensively, their direct action on osteoclasts is still controversial and not conclusive. In this study, we investigated the direct participation ...

The phytocomponent p-hydroxycinnamic acid (HCA) has been shown to have inhibitory effects on bone-resorbing factor-stimulated bone resorption in rat femoral tissues in vitro. The effects of HCA on osteoclast-like cell formation in mouse bone marrow cultures in vitro were investigated. The bone marrow cells were cultured for 7 days in alpha-minimal essential medium containing a bone-resorbing ag...