title: Osteoprotegerin (OPG) and RANKL expression and distribution in developing human craniomandibular joint.
abstract: During embryogenesis the bone tissue of craniomandibular joint (CMJ) is formed through two pathways: intramembranous ossification and endochondral ossification. The development process is under the control of regulatory factors. The osteoprotegerin (OPG) and the receptor activator of nuclear factor (NF)-kappaB ligand are key regulators of osteoclastogenesis. The aim of this study is the localization of OPG and RANKL mRNA and protein in the foetal CMJ by immunohistochemistry (IHC) and in situ hybridization (ISH). The main results were: OPG and RANKL mRNA and protein were co-localized in the same cell types; OPG and RANKL were specially immunolocated in osteogenic cells; immunolabeling was often seen in the nucleus and cytoplasm of otherwise negative hypertrophic chondrocytes; IHC and ISH labeling decreased from proliferative to hypertrophic chondrocytes; early osteocytes showed dual protein expression and some of the mature osteocytes were ISH-negative; periosteal osteoclasts and chondroclasts were mostly stained by IHC and variably labeled by ISH; the new bone matrix and trabecular borders showed intense immunolabeling. The co-expression of OPG and RANKL in the same bone cell types confirms their strictly coupled action in the regulation of bone metabolism in the CMJ development and their extracellular presence in the new bone matrix and trabecular borders suggests a local regulatory role.
authors.affiliation: Department of Pathology, Medical School, University of Valencia, Av Blasco Ibañez 17, 46010 Valencia, Spain. carmen.carda@uv.es
authors.forename: C
authors.initials: C
authors.lastname: Carda
authors.forename: G
authors.initials: G
authors.lastname: Silvestrini
authors.forename: M E
authors.initials: ME
authors.lastname: Gomez de Ferraris
authors.forename: A
authors.initials: A
authors.lastname: Peydró
authors.forename: E
authors.initials: E
authors.lastname: Bonucci
mesh_terms: D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D002358:Cartilage, Articular / Q000196:embryology / Q000378:metabolism; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D010012:Osteogenesis; D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger / Q000096:biosynthesis; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis* / Q000235:genetics; D018124:Receptors, Tumor Necrosis Factor / Q000096:biosynthesis* / Q000235:genetics; D013704:Temporomandibular Joint / Q000196:embryology / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C505686:TNFRSF11A protein, human; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human