title: Primary human bone marrow adipocytes support TNF-α-induced osteoclast differentiation and function through RANKL expression.
abstract: OBJECTIVE
  In previous reports, it was demonstrated that bone marrow adipocytes were related to steroid osteoporosis through osteoclastogenesis induced by Receptor Activator of Nuclear factor κ-B Ligand (RANKL) expression. The purpose of this study was to evaluate the effect of Tumor necrosis factor-alpha (TNF-α) on RANKL expression in bone marrow adipocytes, and osteoclast differentiation supported by human bone marrow adipocytes.
  
  
  METHODS
  RANKL, osteoprotegerin (OPG), and macrophage-colony stimulating factor (M-CSF) mRNA expression in bone marrow adipocytes and their regulation by TNF-α treatment were measured by real-time RT-PCR. Co-cultures of bone marrow adipocytes and osteoclast precursors were performed with or without TNF-α, and osteoclast differentiation was evaluated morphologically and functionally.
  
  
  RESULTS
  RANKL expression and an increase in the RANKL/OPG ratio in bone marrow adipocytes were stimulated by TNF-α treatment. In co-culture of bone marrow adipocytes and osteoclast precursors with TNF-α, the number of TRAP-positive multinuclear cells and resorption cavity formations of calcium phosphate film were increased. Osteoclast differentiation was suppressed by anti-RANKL antibody treatment. In co-culture with non-cell-contact conditions, no TRAP-positive cells or resorption cavity formations were observed.
  
  
  CONCLUSIONS
  TNF-α increased RANKL expression in primary human bone marrow adipocytes. TNF-α induced the ability of bone marrow adipocytes to promote osteoclast differentiation and activity in a manner directly related to RANKL expression.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Biomedical Science, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan.
authors.forename: Hisataka
authors.initials: H
authors.lastname: Goto
authors.forename: Akira
authors.initials: A
authors.lastname: Hozumi
authors.forename: Makoto
authors.initials: M
authors.lastname: Osaki
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Fukushima
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Sakamoto
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yonekura
authors.forename: Masato
authors.initials: M
authors.lastname: Tomita
authors.forename: Keizo
authors.initials: K
authors.lastname: Furukawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shindo
authors.forename: Hideo
authors.initials: H
authors.lastname: Baba
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D017667:Adipocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D000368:Aged; D000369:Aged, 80 and over; D001854:Bone Marrow Cells / Q000166:cytology*; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics; D002478:Cells, Cultured; D018920:Coculture Techniques; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D053245:RANK Ligand / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D013194:Staining and Labeling; D000071681:Tartrate-Resistant Acid Phosphatase; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D007527:Isoenzymes; D053245:RANK Ligand; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase