title: Enhanced RANK ligand expression and responsivity of bone marrow cells in Paget's disease of bone.
abstract: Paget's disease is characterized by highly localized areas of increased osteoclast (OCL) activity. This suggests that the microenvironment in pagetic lesions is highly osteoclastogenic, or that OCL precursors in these lesions are hyperresponsive to osteoclastogenic factors (or both). To examine these possibilities, we compared RANK ligand (RANKL) mRNA expression in a marrow stromal cell line developed from a pagetic lesion (PSV10) with that in a normal stromal cell line (Saka), and expression in marrow samples from affected bones of Paget's patients with that in normal marrow. RANKL mRNA was increased in PSV10 cells and pagetic marrow compared with Saka cells and normal marrow, and was also increased in marrow from affected bones compared with uninvolved bones from Paget's patients. Furthermore, pagetic marrow cells formed OCLs at much lower RANKL concentrations than did normal marrow. Anti-IL-6 decreased the RANKL responsivity of pagetic marrow to normal levels, whereas addition of IL-6 to normal marrow enhanced RANKL responsivity. Thus, RANKL expression and responsivity is increased in pagetic lesions, in part mediated by IL-6. These data suggest that the combination of enhanced expression of RANKL in affected bones and increased RANKL sensitivity of pagetic OCL precursors may contribute to the elevated numbers of OCLs in Paget's disease.
authors.affiliation: Department of Medicine/Hematology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
authors.forename: C
authors.initials: C
authors.lastname: Menaa
authors.forename: S V
authors.initials: SV
authors.lastname: Reddy
authors.forename: N
authors.initials: N
authors.lastname: Kurihara
authors.forename: H
authors.initials: H
authors.lastname: Maeda
authors.forename: D
authors.initials: D
authors.lastname: Anderson
authors.forename: T
authors.initials: T
authors.lastname: Cundy
authors.forename: J
authors.initials: J
authors.lastname: Cornish
authors.forename: F R
authors.initials: FR
authors.lastname: Singer
authors.forename: J M
authors.initials: JM
authors.lastname: Bruder
authors.forename: G D
authors.initials: GD
authors.lastname: Roodman
mesh_terms: D000906:Antibodies / Q000494:pharmacology; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D001842:Bone and Bones / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D002352:Carrier Proteins / Q000235:genetics*; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D006801:Humans; D015850:Interleukin-6 / Q000502:physiology; D008562:Membrane Glycoproteins / Q000235:genetics*; D010001:Osteitis Deformans / Q000378:metabolism* / Q000473:pathology; D010010:Osteoclasts / Q000378:metabolism; D053245:RANK Ligand; D012333:RNA, Messenger / Q000235:genetics; D053246:Receptor Activator of Nuclear Factor-kappa B; D012016:Reference Values; D017154:Stromal Cells / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D014158:Transcription, Genetic; D000093242:Interleukin-6 Inhibitors
chemical_list: D000906:Antibodies; D002352:Carrier Proteins; D015850:Interleukin-6; D008562:Membrane Glycoproteins; D053245:RANK Ligand; D012333:RNA, Messenger; D053246:Receptor Activator of Nuclear Factor-kappa B; D000093242:Interleukin-6 Inhibitors; C505686:TNFRSF11A protein, human; C505688:TNFSF11 protein, human