title: Receptor activator of nuclear factor-kappaB ligand-induced mouse osteoclast differentiation is associated with switching between NADPH oxidase homologues.
abstract: Reactive oxygen species (ROS) have been suggested to regulate receptor activator of nuclear factor-kappaB ligand (RANKL)-stimulated osteoclast differentiation. Stimulation of wild-type mouse bone marrow monocyte/macrophage lineage (BMM) cells by RANKL down-regulated NADPH oxidase 2 (Nox2) mRNA expression by half. RANKL reciprocally increased Nox1 mRNA levels and newly induced Nox4 transcript expression. BMM cells from Nox1 knockout (Nox1(-/-)) as well as Nox2(-/-) mice generated ROS in response to RANKL and differentiated into osteoclasts in the same way as wild-type BMM cells, which was assessed by the appearance of tartrate-resistant acid phosphatase-positive, multinucleated cells having the ability to form resorption pits and by the expression of osteoclast marker genes. A small interfering RNA (siRNA) targeting Nox1 or Nox2 failed to inhibit the RANKL-stimulated ROS generation and osteoclast formation in wild-type cells, whereas Nox1 and Nox2 siRNAs significantly suppressed the ROS generation and osteoclast formation in Nox2(-/-) and Nox1(-/-) cells, respectively. We also confirmed that Nox4 siRNA did not affect the RANKL-dependent events in Nox2(-/-) cells, whereas p22(phox) siRNA suppressed the events in both wild-type and Nox1(-/-) cells. Collectively, our results suggest that there may be a flexible compensatory mechanism between Nox1 and Nox2 for RANKL-stimulated ROS generation to facilitate osteoclast differentiation.
authors.affiliation: Department of Stress Science, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima 770-8503, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Sasaki
authors.forename: Hironori
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Kumiko
authors.initials: K
authors.lastname: Tominaga
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Masuda
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kawai
authors.forename: Shigetada
authors.initials: S
authors.lastname: Teshima-Kondo
authors.forename: Kuniharu
authors.initials: K
authors.lastname: Matsuno
authors.forename: Chihiro
authors.initials: C
authors.lastname: Yabe-Nishimura
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Rokutan
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D008264:Macrophages / Q000166:cytology / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D009000:Monocytes / Q000166:cytology / Q000502:physiology; D019255:NADPH Oxidases / Q000378:metabolism*; D010010:Osteoclasts / Q000166:cytology* / Q000502:physiology; D020033:Protein Isoforms / Q000378:metabolism; D053245:RANK Ligand / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D053246:Receptor Activator of Nuclear Factor-kappa B / Q000502:physiology
chemical_list: D020033:Protein Isoforms; D053245:RANK Ligand; D017382:Reactive Oxygen Species; D053246:Receptor Activator of Nuclear Factor-kappa B; D019255:NADPH Oxidases