Nox 2 stimulates muscle differentiation via NF-kappaB/iNOS pathway.
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.
Piao
Yu Ji
YJ
Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, #1, Hoegi-dong, Dongdaemoon-gu, Seoul 130-701, Korea.
Seo
Yong Hak
YH
Hong
Feng
F
Kim
Jin Hwan
JH
Kim
Young-Joo
YJ
Kang
Myung Ho
MH
Kim
Bum Shik
BS
Jo
Sangmee Ahn
SA
Jo
Inho
I
Jue
Dae-Myung
DM
Kang
Insug
I
Ha
Joohun
J
Kim
Sung Soo
SS
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
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