title: Role of HSP27 in tumor necrosis factor-α-stimulated interleukin-6 synthesis in osteoblasts.
abstract: Heat shock protein 27 (HSP27) is known to act as a molecular chaperone. We have recently reported that HSP27 regulates osteocalcin synthesis in osteoblast-like MC3T3-E1 cells. In the present study, we investigated the role of HSP27 in tumor necrosis factor-α (TNF-α)-stimulated interleukin-6 (IL-6) synthesis in MC3T3-E1 cells. The levels of IL-6 release and IL-6 mRNA stimulated by TNF-α in MC3T3-E1 cells transfected with HSP27 was significantly higher than those in the control cells. In addition, the levels of secreted IL-6 and IL-6 mRNA in the phospho-mimic HSP27-overexpressing cells were significantly higher than those in the non-phosphoryl-atable HSP27-overexpressing cells. Furthermore, we observed no significant differences in the phosphorylation levels of IκB/NFκB, Akt, and p44/p42 mitogen-activated protein kinase among the 4 types of transfected cells. Therefore, these results strongly suggest that HSP27 enhances TNF-α-stimulated IL-6 synthesis, and that the phosphorylation status of HSP27 is related to IL-6 synthesis in osteoblasts.
authors.affiliation: Department of Orthopedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya , Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kato
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Tokuda
authors.forename: Jun
authors.initials: J
authors.lastname: Mizutani
authors.forename: Seiji
authors.initials: S
authors.lastname: Adachi
authors.forename: Rie
authors.initials: R
authors.lastname: Matsushima-Nishiwaki
authors.forename: Hideo
authors.initials: H
authors.lastname: Natsume
authors.forename: Osamu
authors.initials: O
authors.lastname: Kozawa
authors.forename: Takanobu
authors.initials: T
authors.lastname: Otsuka
mesh_terms: D000818:Animals; D002460:Cell Line; D055551:HSP27 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D055551:HSP27 Heat-Shock Proteins; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha