title: Histone deacetylase inhibition enhances in-vivo bone regeneration induced by human periodontal ligament cells.
abstract: Periodontal ligament cells have the potential to differentiate into bone forming osteoblasts and thus represent a good cellular candidate for bone regeneration. This study aimed to investigate the effect of inhibition of histone deacetylases, using the inhibitor Trichostatin A (TSA), on bone regeneration by human periodontal ligament cells (hPDLCs) in a mouse calvaria bone defect.
  
  
  
  RUNX2 protein and its acetylation was analyzed by immunoprecipitation and western blotting. The effect of TSA on osteogenic differentiation of hPDLCs was investigated using in vitro 3D cultures. hPDLCs were pre-incubated with and without TSA and implanted in mouse calvaria defects with polycaprolactone/polyethylene glycol (PCL/PEG) co-polymer scaffold. Micro-CT scanning and bone histomorphometric analysis were used to quantify the amount of bone. Survival of hPDLCs as xenogenic grafts was verified by immunohistochemistry with anti-human β1-integrin. The immunological response of mice against hPDLCs xenografts was evaluated by measuring total IgG and hPDLCs-specific IgG.
  
  
  
  Beside affecting histone protein, TSA also induced hyper-acetylation of RUNX2 which might be a crucial mechanism for enhancing osteogenesis by hPDLCs. TSA enhanced mineral deposition by hPDLCs in in vitro 3D cultures and had no effect on cell viability. In vivo bone regeneration of mouse calvaria defects was significantly enhanced by TSA pre-treated hPDLCs. By using anti-human ß1 integrin hPDLCs were shown to differentiate into osteocyte-like cells that were present in newly formed bone. hPDLCs, as a xenograft, slightly but not significantly induced an immunological response in recipient mice as demonstrated by the level of total IgG and hPDLCs-specific IgG.
  
  
  
  Inhibition of histone deacetylases by TSA enhanced in vivo bone regeneration by hPDLCs. The data strongly suggest a novel approach to regenerate bone tissue.
authors.affiliation: Mineralized Tissue Research Unit, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand; Department of Dental Basic Sciences, Faculty of Odonto-Stomatology, University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam; Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Nam Cong-Nhat
authors.initials: NC
authors.lastname: Huynh
authors.affiliation: Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, Research Institute MOVE, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands.
authors.forename: Vincent
authors.initials: V
authors.lastname: Everts
authors.affiliation: Department of Pharmacology, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Nifuji
authors.affiliation: Mineralized Tissue Research Unit, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand; Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Prasit
authors.initials: P
authors.lastname: Pavasant
authors.affiliation: Research Unit on Oral Microbiology and Immunology, Microbiology Department, Faculty of Dentistry Chulalongkorn University, Bangkok, Thailand. Electronic address: ruchanee.a@chula.ac.th.
authors.forename: Ruchanee Salingcarnboriboon
authors.initials: RS
authors.lastname: Ampornaramveth
mesh_terms: D000107:Acetylation; D000293:Adolescent; D000328:Adult; D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects*; D002113:Calcification, Physiologic / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D007074:Immunoglobulin G / Q000378:metabolism; D019012:Integrin beta1 / Q000378:metabolism; D051379:Mice; D010011:Osteocytes / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects; D010513:Periodontal Ligament / Q000166:cytology*; D012886:Skull / Q000000981:diagnostic imaging / Q000502:physiology; D055114:X-Ray Microtomography; D055815:Young Adult
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D007074:Immunoglobulin G; D019012:Integrin beta1; C012589:trichostatin A
keywords: Bone regeneration; Histone deacetylase; Osteoblast; Periodontal ligament cells; Trichostatin