title: Nuclear Nrf2 induction by protein transduction attenuates osteoclastogenesis.
abstract: It has been reported that reactive oxygen species (ROS) play a role as intracellular signaling molecules in RANKL stimulation. Previously we demonstrated that induction of cytoprotective enzyme expression by Nrf2-gene transfer successfully ameliorated RANKL-dependent osteoclastogenesis. In the present study, we hypothesized that Nrf2 activation by inhibiting ubiquitination and degradation of Nrf2 by ETGE-peptide would induce Nrf2-dependent cytoprotective enzyme expression, attenuate ROS signaling, and thereby inhibit RANKL-dependent osteoclastogenesis. ETGE-peptide containing a cell-permeable sequence (seven consecutive arginine; 7R-ETGE) was applied to a mouse macrophage cell-line RAW 264.7 cell or a primary macrophage culture. ETGE-peptide prevents Keap1 from binding to Nrf2. Nrf2 nuclear translocation and Nrf2-dependent cytoprotective enzyme induction was observed. The effects of 7R-ETGE on RANKL-dependent induction of intracellular ROS levels and osteoclastogenesis were examined. Finally, the protective effect of 7R-ETGE on RANKL-mediated bone destruction was investigated in mice. 7R-ETGE dose-dependently induced nuclear Nrf2, followed by the induction of cytoprotective enzyme expression at both the gene and protein level. 7R-ETGE inhibited upregulation of intracellular ROS levels by RANKL stimulation, and osteoclastogenesis was attenuated. Of particular interest was that local injection of 7R-ETGE ameliorated RANKL-mediated bone destruction. Local induction of nuclear Nrf2 by protein transduction is a potential novel therapeutic target for bone destruction diseases such as periodontitis and rheumatoid arthritis.
authors.affiliation: Tohoku University Hospital, Maxillo-Oral Disorders; Department of orthodontics, School of Dental Medicine, Tsurumi University 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa 230-8501, Japan. Electronic address: kanzaki-h@tsurumi-u.ac.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kanzaki
authors.affiliation: Tohoku University Graduate School of Dentistry, Oral MicrobiologySendai, Miyagi 980-8577, Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Shinohara
authors.affiliation: Department of Periodontal Medicine, Division of Applied Life Science, Hiroshima University Graduate School of Biomedical & Health Sciences Hiroshima University, Hiroshima, Japan.
authors.forename: Mikihito
authors.initials: M
authors.lastname: Kajiya
authors.affiliation: Department of orthodontics, School of Dental Medicine, Tsurumi University 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa 230-8501, Japan.
authors.forename: Sari
authors.initials: S
authors.lastname: Fukaya
authors.affiliation: Department of orthodontics, School of Dental Medicine, Tsurumi University 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa 230-8501, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Miyamoto
authors.affiliation: Department of orthodontics, School of Dental Medicine, Tsurumi University 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa 230-8501, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Nakamura
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D008297:Male; D008810:Mice, Inbred C57BL; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology*; D010010:Osteoclasts / Q000187:drug effects / Q000502:physiology*; D053245:RANK Ligand / Q000494:pharmacology / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: C000600163:7R-ETGE peptide; D050071:Bone Density Conservation Agents; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; D009842:Oligopeptides; D053245:RANK Ligand; D017382:Reactive Oxygen Species
keywords: Cytoprotective enzyme; Nrf2; Osteoclast; Oxidative stress; RANKL; ROS