Modulation of osteoclastogenesis through adrenomedullin receptors on osteoclast precursors: initiation of differentiation by asymmetric cell division.

Adrenomedullin (ADM), a member of the calcitonin family of peptides, is a potent vasodilator and was shown to have the ability to modulate bone metabolism. We have previously found a unique cell surface antigen (Kat1 antigen) expressed in rat osteoclasts, which is involved in the functional regulation of the calcitonin receptor (CTR). Cross-linking of cell surface Kat1 antigen with anti-Kat1 antigen monoclonal antibody (mAbKat1) stimulated osteoclast formation only under conditions suppressed by calcitonin.

In vitro and in vivo detection of tunneling nanotubes in normal and pathological osteoclastogenesis involving osteoclast fusion.

Osteoclasts are multinucleated cells formed through specific recognition and fusion of mononuclear osteoclast precursors derived from hematopoietic stem cells. Detailed cellular events concerning cell fusion in osteoclast differentiation remain ambiguous. Tunneling nanotubes (TNTs), actin-based membrane structures, play an important role in intercellular communication between cells.

Replacement Process of Carbonate Apatite by Alveolar Bone in a Rat Extraction Socket.

The objective of this study was to investigate a bone graft substitute containing carbonate apatite (COAp) to analyze bone replacement and the state of bone formation in vitro and in vivo compared with autogenous bone (AB) or control. An osteoclast precursor cell line was cultured with AB or COAp, and morphological analysis using scanning electron microscopy and a tartrate-resistant acid phosphatase activity assay were performed. The right maxillary first and second molars of Wistar rats were extracted and compensated by AB or COAp granules.

IgG immune complexes with Staphylococcus aureus protein A enhance osteoclast differentiation and bone resorption by stimulating Fc receptors and TLR2.

Staphylococcus aureus is a main pathogen of osteomyelitis and protein A is a virulence factor with high affinity for IgG. In this study, we investigated whether S. aureus affects the differentiation and bone resorption of osteoclasts through the IgG-binding capacity of protein A.

Enhanced junctional epithelial permeability in TRPV4-deficient mice.

Background And Objective: As the interface between the oral cavity and the teeth, the junctional epithelial barrier is critical for gingival defense. The junctional epithelium is subject to mechanical stresses from biting force or external insults such as bacterial attacks, but little is known about the effects of mechanical stimuli on epithelial functions. Transient receptor potential vanilloid 4 (TRPV4) functions as a mechanosensitive nonselective cation channel.

Membrane nanotube formation in osteoclastogenesis.

Membrane tunneling nanotubes (TNTs) are unique intercellular structures, which enable rapid transport of various materials and rapid communication between cells present in a long distance. During osteoclastogenesis, mononuclear osteoclast precursors form abundant TNTs in prior to cell-cell fusion. Here we introduce a protocol for detecting TNTs during osteoclastogenesis by use of live cell imaging utilizing a confocal laser microscopy.

The thermosensitive TRPV3 channel contributes to rapid wound healing in oral epithelia.

The oral cavity provides an entrance to the alimentary tract to serve as a protective barrier against harmful environmental stimuli. The oral mucosa is susceptible to injury because of its location; nonetheless, it has faster wound healing than the skin and less scar formation. However, the molecular pathways regulating this wound healing are unclear.

Regulation of osteoclastogenesis through Tim-3: possible involvement of the Tim-3/galectin-9 system in the modulation of inflammatory bone destruction.

Galectins are a unique family of lectins bearing one or two carbohydrate recognition domains (CRDs) that have the ability to bind molecules with β-galactoside-containing carbohydrates. It has been shown that galectins regulate not only cell growth and differentiation but also immune responses, as well as inflammation. Galectin-9, a tandem repeat type of galectin, was originally identified as a chemotactic factor for eosinophils, and is also involved in the regulatory process of inflammation.

Tunneling nanotube formation is essential for the regulation of osteoclastogenesis.

Osteoclasts are the multinucleated giant cells formed by cell fusion of mononuclear osteoclast precursors. Despite the finding of several membrane proteins involving DC-STAMP as regulatory proteins required for fusion among osteoclast precursors, cellular and molecular events concerning this process are still ambiguous. Here we identified Tunneling Nanotubes (TNTs), long intercellular bridges with small diameters, as the essential cellular structure for intercellular communication among osteoclast precursors in prior to cell fusion.

TRPV2 expression in rat oral mucosa.

The oral mucosa is a highly specialised, stratified epithelium that confers protection from infection and physical, chemical and thermal stimuli. The non-keratinised junctional epithelium surrounds each tooth like a collar and is easily attacked by foreign substances from the oral sulcus. We found that TRPV2, a temperature-gated channel, is highly expressed in junctional epithelial cells, but not in oral sulcular epithelial cells or oral epithelial cells.

Capsaicin receptor expression in the rat temporomandibular joint.

Experimentally, temporomandibular joint (TMJ) nerve units respond to capsaicin, which is used clinically to treat TMJ pain. However, the existence of capsaicin receptors in the TMJ has not previously been clearly demonstrated. Immunohistochemical analysis has revealed the presence of transient receptor potential vanilloid subtype 1 (TRPV1) expression in the nerves and synovial lining cells of the TMJ.

Immunocytochemical localization of the neurokinin 1 receptor in rat dental pulp.

The dentin-pulp complex is a peripheral end-organ supplied by dense sensory nerve fibers. Substance P, a representative neuropeptide widely distributed in the dental pulp, has been reported to play roles in pain transmission and the amplification of inflammation. We analyzed here the expression of the neurokinin 1 (NK1) receptor, preferentially activated by substance P, using immunocytochemistry in rat dental pulp at both the light and electron microscopic levels.

[Effect of endogenous carbon monoxide on oxidant-mediated multiple organ injury following limb ischemia-reperfusion in rats].

Objective: To determine the role of endogenous carbon monoxide(CO) in oxidant-mediated organ injury following limb ischemia-reperfusion (I/R) in rats.

Methods: Sixty-four SD rats were divided into 4 groups: Sham group, Sham + zinc protoporphyrin (ZnPP, an inhibitor of heme oxygenase activity), 2-hour ischemia followed by 4-hour reperfusion (I/R) group and I/R + ZnPP group. Carboxyhemoglobin (COHb) level in the artery blood, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in the lung, heart, liver and kidney were detected.

Three-dimensional wall structure and the innervation of dental pulp blood vessels.

The involvement of neural components in plasma extravasation and blood flow in the dental pulp has been established by pharmacological and physiological studies. We review here the segmental constitution of pulp vessels and the possible involvement of neural components in both the contractility and permeability of the pulp vessels from a morphological viewpoint. Six vascular segments can be identified based on the morphology of peri-endothelial cells, such as smooth muscle cells and pericytes.