Peroxisome proliferator activated receptor gamma interacts with bone morphogenetic protein, Wnt, TAZ, and insulin-like growth factor-I, which are required for the process of osteoblast differentiation, regulating the mesenchymal stem cells (MSCs) into adipocytes and osteoblasts differentiation, thus impact on the osteoblast-mediated bone formation in bone remodeling, and, through RANKL and other factors directly or indirectly, regulate osteoclast-mediated bone resorption. This article reviews new researches for the influence of peroxisome proliferator activated receptor gamma on osteoblast and osteoclast function in bone remodeling.
Bone Remodeling ; physiology ; Humans ; Osteoblasts ; physiology ; Osteoclasts ; physiology ; PPAR gamma ; physiology

Osteoclast, a huge coenocytes,originates from mononuclear macrophages or monocytic series hematopoietic precursor cell, plays an important role in the progree of bone resorption. Formation and abnormal activity of osteoclast may cause osteoprosis, rheumatoid arthritis and aseptic loosening after arthroplasty. Therefore, osteoclast is the target for treating these disease. At present, a lot of study on formation of osteoclast were reported, but the study on how to identify and degradation of bone tissue is not yet reported. Bone mineral are seen as important component of identifing osteoclast, and the research suggested that bone matrix is not the essential ingredients of activiting osteoclast, petri dish covered by vitronectin also can make osteoclast occure certain form of bone resorption, vitronectin plays an significant role in activiting osteoclast. Otherwise, the research found that swallowing and secretion of bone matrix degradation products is benefit for differentiation of osteoclast and maintain of function, and this may be therapeutic target for treatment of musculoskeletal disorders.
Animals ; Bone Matrix ; metabolism ; Bone Resorption ; Humans ; Osteoclasts ; physiology

Tunneling nanotube (TNT) is a newly discovered communication mode between animal cells in recent years, which have important physiological and pathological significance. However, the role of TNT in bone biology is still unclear. At present, there are many reports about tunneling nanotubes in bone marrow mesenchymal stem cells, osteoclast precursor cells, osteoblasts and immune cells. This review describes the research advances of TNT and its research progress in bone biology. It looks forward to the research direction of TNT in oral and maxillofacial bone development and bone biology, to provide new strategies for the maintenance of bone homeostasis and the treatment of bone diseases.
Animals ; Bone and Bones ; Nanotubes ; Osteoclasts ; Biology ; Cell Communication/physiology*

The physiological reconstruction of bone is strictly dependent on bone resorption. Bone resorption is believed to be a complicated molecular reaction process that occurs in the microcircumstance of bone tissue. A lot of enzymes and factors take part in this process, yet there are not enough data with reference to the activation of osteoclast, resorption of bone matrix, regulation of bone resorption. In this paper we review the importance of matrix metalloproteinases (MMPs) in transfer of osteoclast and degradation of bone matrix, and the function of receptor activator of NF-kappaB-ligand (RANKL) and osteoprotegerin (OPG) in regulation of bone resorption.
Bone Resorption ; Humans ; Matrix Metalloproteinases ; metabolism ; Osteoclasts ; physiology ; Osteoprotegerin ; physiology ; RANK Ligand ; physiology

Osteogenesis and angiogenesis are two closely correlated processes during bone growth, development, remodelling and repair.Vascular endothelial growth factor (VEGF) is an essential mediator during the process of angiogenesis. Based on an extensive literature search, which was carried out using the PubMed database and the keywords of osteogenesis, VEGF, endochondral ossification and intramembranous ossification, this manuscript reviews the role of VEGF in ossification, with emphasis on its effect in endochondral and intramembranous ossification. Osteogenesis and angiogenesis are closely correlated processes. VEGF acts as an essential mediator during these processes. It not only functions in bone angiogenesis but also in various aspects of bone development.
Animals ; Bone Remodeling ; physiology ; Bone and Bones ; cytology ; physiology ; Calcification, Physiologic ; physiology ; Cartilage ; cytology ; physiology ; Humans ; Neovascularization, Physiologic ; physiology ; Osteoclasts ; physiology ; Osteogenesis ; physiology ; Vascular Endothelial Growth Factor A ; physiology

Bidirectional Eph-Ephrin signaling as a focal point of research in cell-cell communications is critical for generation of nerves and vesssels as well as invation and metastasis of tumor cells. The roles for Ephrin-Eph bidirectional signaling in bone remodeling were important. EphrinB2 is expressed on osteoblasts and EphB4 is expressed on osteoclasts. Forward signaling through the EphB4 receptor into mesenchymal precursors promotes osteoblast differentiation, while reverse signaling through the EphrinB2 ligand into osteoclast suppresses differentiation. Signaling between the ligand EphrinB2 and the receptors EphB4 explains bidirectional signaling between osteoblasts and osteoclasts,bone absorption and remodeling, which may lay a theoretical foundation for identifying drug targeting and preventing and treating bone loss.
Animals ; Bone Remodeling ; physiology ; Ephrin-B2 ; physiology ; Humans ; Osteoblasts ; cytology ; Osteoclasts ; cytology ; Receptor, EphB4 ; physiology ; Signal Transduction ; physiology

Androgen is an anabolic steroid composed of 19 carbon atoms. As a sex hormone, it has far-ranging effects on many sites within the body, including bone metabolism. Androgen has important effects on bone development and homeostasis. It has been proved that the androgen receptor (AR) expresses in bone cells, which indicates that androgen has direct effects on bone cells. Furthermore there is convincing evidence that aromatization to estrogen is an important way of mediating the action of testosterone. Androgen not only plays an important role in gaining the peak bone mass and maintaining the bone mass, but also has a close correlation with aging-related bone loss.
Androgens ; physiology ; Animals ; Bone Density ; physiology ; Bone and Bones ; physiology ; Female ; Humans ; Male ; Osteoblasts ; physiology ; Osteoclasts ; physiology ; Osteoporosis ; physiopathology ; Rats ; Receptors, Androgen ; physiology

Tooth eruption is a series of complicated physiological processes occurring once the crown is formed completely, as well as when the tooth moves toward the occasion plane. As such, the tooth moves through the alveolar bone and the oral mucosa until it finally reaches its functional position. Most studies indicate that the process of tooth eruption involves the alveolar bone, dental follicles, osteoclasts, osteoblasts, and multiple cytokines. Dental follicles regulate both resorption and formation of the alveolar bone, which is required for tooth eruption. Furthermore, root formation with periodontal ligament facilitates continuous tooth eruption. However, the exact mechanism underlying tooth eruption remains unclear. Hence, this review describes the recent research progress on the cellular and molecular mechanisms of tooth eruption.
Dental Sac ; Humans ; Osteoblasts ; Osteoclasts ; Periodontal Ligament ; Tooth ; Tooth Eruption ; physiology ; Tooth Root

Cellular immune responses as well as generalized and periarticular bone loss are the key pathogenic features of rheumatoid arthritis (RA). Under the pathological conditions of RA, dysregulated inflammation and immune processes tightly interact with skeletal system, resulting in pathological bone damage via inhibition of bone formation or induction of bone resorption. Single-cell omics technologies are revolutionary tools in the field of modern biological research.They enable the display of the state and function of cells in various environments from a single-cell resolution, thus making it conducive to identify the dysregulated molecular mechanisms of bone destruction in RA as well as the discovery of potential therapeutic targets and biomarkers. Here, we summarize the latest findings of single-cell omics technologies in osteoimmunology research in RA. These results suggest that single-cell omics have made significant contributions to transcriptomics and dynamics of specific cells involved in bone remodeling, providing a new direction for our understanding of cellular heterogeneity in the study of osteoimmunology in RA.
Humans ; Osteoclasts/physiology* ; Arthritis, Rheumatoid/pathology* ; Inflammation/pathology* ; Bone and Bones/pathology* ; Bone Resorption/pathology*

Our previous studies on the function of the osteoblasts (OBs) have shown that worn titanium particles decrease osteoblast function and promot secretion of bone resorption cytokines of OBs surrounding the synovium-like interface membrane of loosening implants. The current study was aimed to test the hypothesis that osteoclasts (OCs) bone absorption function is induced by conditioned media (CM) prepared from OBs loaded in the presence or absence of titanium particles (with three mean diameters 6.9 microm, 2.7 microm, and 0.9 microm, respectively). The effects of CM on OCs function were examined using a combination of the morphological characteristics tests, i.e., TRAP dyeing, scanning electron microscopy, F-actin immunofluorescence protocol for confocal microscopy, bone resorption lacunae assay, osteoclastic calcium tracking, with biochemical evaluation, i.e., C-terminal cross-linked telopeptides of type I collagen evaluated with ABC-ELISA method. The results showed that CM from 0.9 microm titanium particles could induce osteoclastic differentiation and formation, could partially influence the survival of the OCs; while CM of 2.7 microm and 6.9 microm titanium particles, especially the latter, could obviously augmented osteoclastic activity, survival, or differentiation. The stimulation of osteoclast function may be due to a parallel increase in the intracellular free calcium concentration. The present study provides strong support for the hypothesis that osteoclastic activity, survival, or differentiation are very important in the development of aseptic loosening. The development of therapeutic interventions to reduce osteoclastic function and optimization of biomaterials may be useful approaches for improving the performance of orthopaedic implants.
Animals ; Bone Resorption ; Cells, Cultured ; Osteoblasts ; cytology ; physiology ; Osteoclasts ; cytology ; physiology ; Particle Size ; Prosthesis Failure ; Rabbits ; Titanium ; pharmacology