title: Chaetocin inhibits RANKL-induced osteoclast differentiation through reduction of Blimp1 in Raw264.7 cells.
abstract: OBJECTIVE
  Periodontitis is one of the most common bone-destructive diseases. Osteoclast is differentiated from hematopoietic macrophage-like cells through receptor activator of NFκB ligand (RANKL)-RANK signaling system, and the reduction in osteoclast formation may result in prevention of bone-resorptive diseases. Chaetocin is a compound isolated from fungal cultures and has been reported as a potent and selective inhibitor of suppressor of variegation 3-9 homolog 1 (Suv39h1), which catalyzes histone methylation on histone H3 lysine 9 (H3K9) residues. However, the effect of chaetocin on osteoclast differentiation is uncertain. In this study, we examine the effect of chaetocin on RANKL-induced osteoclast differentiation and cell growth.
  
  
  METHODS
  Mouse macrophage-like Raw264.7 cells were treated with RANKL in the presence or absence of chaetocin, and tartrate-resistant acid phosphatase (TRAP) staining was performed. Cell growth was measured as the amount of DNA stained with SYTOX Green dye. Expression and production of osteoclast differentiation markers, anti-osteoclastogenic genes, B lymphocyte-induced maturation protein-1 (Blimp1), and cell growth suppressors were examined by qRT-PCR or/and Western blot analysis.
  
  
  RESULTS
  Here we show that chaetocin dose-dependently reduced RANKL-induced osteoclast differentiation and cell growth via Blimp1 downregulation which results in the upregulation of osteoclast differentiation inhibitors and cell growth suppressors. These effects were not derived from the chaetocin's inhibitory effect of Suv39h1.
  
  
  CONCLUSIONS
  These results suggest that chaetocin suppresses RANKL-induced osteoclastogenesis and cell growth through blimp1 downregulation, followed by induction of anti-osteoclastogenic genes and cell growth suppressors, without inhibition of Suv39h1. Thus, chaetocin might be a drug candidate for the prevention of bone resorption in bone-destructive diseases.
authors.affiliation: Department of Biochemistry, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Department of Endodontics, School of Dentistry, Shandong University, 44-1 West Wen Hua Road, Jinan, Shandong Province 250012, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Zhao
authors.affiliation: Department of Biochemistry, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Division of Functional Morphology, Dental Research Center, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan. Electronic address: tsuda.hiromasa@nihon-u.ac.jp.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Tsuda
authors.affiliation: Department of Biochemistry, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Murofushi
authors.affiliation: Department of Oral Microbiology, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Division of Immunology and Pathobiology, Dental Research Center, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Imai
authors.affiliation: Department of Oral Microbiology, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Division of Immunology and Pathobiology, Dental Research Center, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
authors.forename: Kuniyasu
authors.initials: K
authors.lastname: Ochiai
authors.affiliation: Department of Periodontics, School of Dentistry, Shandong University, 44-1 West Wen Hua Road, Jinan, Shandong Province 250012, China.
authors.forename: Pishan
authors.initials: P
authors.lastname: Yang
authors.affiliation: Department of Biochemistry, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Division of Functional Morphology, Dental Research Center, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D051379:Mice; D010010:Osteoclasts / Q000187:drug effects / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology; D000074462:Positive Regulatory Domain I-Binding Factor 1; D053245:RANK Ligand / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D010879:Piperazines; C513258:Prdm1 protein, mouse; D053245:RANK Ligand; C505689:Tnfsf11 protein, mouse; D014157:Transcription Factors; C002511:chaetocin; D000074462:Positive Regulatory Domain I-Binding Factor 1
keywords: Blimp1; Cell growth; Chaetocin; Osteoclast differentiation; Transcriptional repressors