Regulation of Osteoclastogenesis by Gap Junction Communication.
From: Department of Odontology, Division of Oral Cell Biology, Umeå University, SE 901 87, Umeå, Sweden.
Journal of cellular biochemistry
- Publish Date: Oct 2006
- ISSN: 0730-2312
- Volume: 99
- Issue: 2
- Pages: 528-37
- Medium: Print
- Language: English
- Citation (JAMA): Matemba Stephen F, Lie Anita, Ransjö Maria, et al. Regulation of Osteoclastogenesis by Gap Junction Communication.. J. Cell. Biochem. Oct 2006;99:528-37
Abstract
Receptor activator of NF-kappaB ligand (RANKL) is crucial in osteoclastogenesis but signaling events involved in osteoclast differentiation are far from complete and other signals may play a role in osteoclastogenesis. A more direct pathway for cellular crosstalk is provided by gap junction intercellular channel, which allows adjacent cells to exchange second messengers, ions, and cellular metabolites. Here we have investigated the role of gap junction communication in osteoclastogenesis in mouse bone marrow cultures. Immunoreactive sites for the gap junction protein connexin 43 (Cx43) were detected in the marrow stromal cells and in mature osteoclasts. Carbenoxolone (CBX) functionally blocked gap junction communication as demonstrated by a scrape loading Lucifer Yellow dye transfer technique. CBX caused a dose-dependent inhibition (significant > or = 90 microM) of the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells formed in 7- to 8-day marrow cultures stimulated by parathyroid hormone (PTH; 10 nM) or forskolin (FSK; 1 microM). Furthermore, CBX (100 microM) significantly inhibited prostaglandin E2 (PGE2; 10 microM) and 1,25(OH)2-vitamin D3 stimulated osteoclast differentiation in the mouse bone marrow cultures. Consequently, quantitative real-time polymerase chain reaction (PCR) analysis demonstrated that CBX downregulated the expression of osteoclast phenotypic markers, but without having any significant effects on RANK, RANKL, and osteoprotegerin (OPG) mRNA expression. However, the results demonstrated that CBX significantly inhibits RANKL-stimulated (100 ng/ml) osteoclastogenesis in the mouse bone marrow cultures. Taken together, our results suggests that gap junctional diffusion of messenger molecules interacts with signaling pathways downstream RANKL in osteoclast differentiation. Further studies are required to define the precise mechanisms and molecular targets involved.
Mesh Headings (Keywords): Animals, Base Sequence, Bone Resorption, Calcitriol, Carbenoxolone, Carrier Proteins, Cell Communication, Cell Differentiation, Cells, Cultured, Connexin 43, DNA, Complementary, Dinoprostone, Forskolin, Gap Junctions, Glycoproteins, Membrane Glycoproteins, Mice, Osteoclasts, Osteoprotegerin, Parathyroid Hormone, RANK Ligand, RNA, Messenger, Receptor Activator of Nuclear Factor-kappa B, Receptors, Cytoplasmic and Nuclear, Receptors, Tumor Necrosis Factor, Signal Transduction
Check for Full Text / PubMed Unique Identifier (PMID): 16639710
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