title: Nox 2 stimulates muscle differentiation via NF-kappaB/iNOS pathway.
abstract: The NF-kappaB/iNOS pathway stimulates muscle differentiation downstream of the PI 3-kinase/p38 MAPK pathway and diverse antioxidants block muscle differentiation. Therefore, we here investigated whether Nox 2 links those two myogenic pathways in H9c2 and C2C12 myoblasts. Compared with the proliferation stage, ROS generation was enhanced from the early stage of differentiation and gradually increased as differentiation progressed. Antioxidants suppressed the activated NF-kappaB/iNOS pathway during muscle differentiation. Nox 2 activity was also increased during muscle differentiation. Treatment with DPI and apocynin, two inhibitors of NADPH oxidase, and suppression of Nox 2 expression using siRNA, but not Nox 1, inhibited NADPH oxidase activity, muscle differentiation, and the NF-kappaB/iNOS pathway. Inhibition of PI 3-kinase and p38 MAPK suppressed the Nox 2/NF-kappaB/iNOS pathway. Nitric oxide restored muscle differentiation blocked by treatment with antioxidants or suppression of the Nox 2/NF-kappaB/iNOS pathway. In conclusion, Nox 2 stimulates muscle differentiation downstream of the PI 3-kinase/p38 MAPK pathway by activating the NF-kappaB/iNOS pathway via ROS generation.
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, #1, Hoegi-dong, Dongdaemoon-gu, Seoul 130-701, Korea.
authors.forename: Yu Ji
authors.initials: YJ
authors.lastname: Piao
authors.forename: Yong Hak
authors.initials: YH
authors.lastname: Seo
authors.forename: Feng
authors.initials: F
authors.lastname: Hong
authors.forename: Jin Hwan
authors.initials: JH
authors.lastname: Kim
authors.forename: Young-Joo
authors.initials: YJ
authors.lastname: Kim
authors.forename: Myung Ho
authors.initials: MH
authors.lastname: Kang
authors.forename: Bum Shik
authors.initials: BS
authors.lastname: Kim
authors.forename: Sangmee Ahn
authors.initials: SA
authors.lastname: Jo
authors.forename: Inho
authors.initials: I
authors.lastname: Jo
authors.forename: Dae-Myung
authors.initials: DM
authors.lastname: Jue
authors.forename: Insug
authors.initials: I
authors.lastname: Kang
authors.forename: Joohun
authors.initials: J
authors.lastname: Ha
authors.forename: Sung Soo
authors.initials: SS
authors.lastname: Kim
mesh_terms: D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002460:Cell Line; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D008562:Membrane Glycoproteins / Q000502:physiology*; D051379:Mice; D009132:Muscles / Q000166:cytology* / Q000201:enzymology / Q000378:metabolism; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000502:physiology*; D016328:NF-kappa B / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species; D020133:Reverse Transcriptase Polymerase Chain Reaction; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D017931:DNA Primers; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C496318:Nos2 protein, rat; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; D019869:Phosphatidylinositol 3-Kinases; D048051:p38 Mitogen-Activated Protein Kinases