Reactive oxygen species derived from Nox4 mediate BMP2 gene transcription and osteoblast differentiation

Chandi C. Mandal, Suthakar Ganapathy, Yves Gorin, Kalyankar Mahadev, Karen Block, Hanna E. Abboud, Stephen E. Harris, Goutam Ghosh-Choudhury, Nandini Ghosh-Choudhury

Research output: Contribution to journalArticle

87 Scopus citations

Abstract

BMP-2 (bone morphogenetic protein-2) promotes differentiation of osteoblast precursor cells to mature osteoblasts that form healthy bone. In the present study, we demonstrate a novel mechanism of BMP-2-induced osteoblast differentiation. The antioxidant NAC (N-acetyl-L-cysteine) and the flavoprotein enzyme NAD(P)H oxidase inhibitor DPI (diphenyleneiodonium) prevented BMP-2-stimulated alkaline phosphatase expression and mineralized bone nodule formation in mouse 2T3 pre-osteoblasts. BMP-2 elicited a rapid generation of ROS (reactive oxygen species) concomitant with increased activation of NAD(P)H oxidase. NAC andDPI inhibited BMP-2-induced ROS production and NAD(P)H oxidase activity respectively. NAD(P)H oxidases display structurally similar catalytic subunits (Nox1-5) with differential expression in various cells. We demonstrate that 2T3 pre-osteoblasts predominantly express the Nox4 isotype of NAD(P)H oxidase. To extend this finding, we tested the functional effects of Nox4. Adenovirus-mediated expression of dominant-negative Nox4 inhibited BMP-2-induced alkaline phosphatase expression. BMP-2 promotes expression of BMP-2 for maintenance of the osteoblast phenotype. NAC and DPI significantly blocked BMP-2-stimulated expression of BMP2 mRNA and protein due to a decrease in BMP2 gene transcription. Dominant-negative Nox4 also mimicked this effect of NAC and DPI. Our results provide the first evidence for a new signalling pathway linking BMP-2-stimulated Nox4-derived physiological ROS to BMP-2 expression and osteoblast differentiation.

Original languageEnglish (US)
Pages (from-to)393-402
Number of pages10
JournalBiochemical Journal
Volume433
Issue number2
DOIs
StatePublished - Jan 15 2011

Keywords

  • Bone morphogenetic protein-2 (BMP-2)
  • Bone morphogenetic protein-2 gene autoregulation
  • Bone morphogenetic protein-2 signalling
  • Osteoblast differentiation
  • Reactive oxygen species

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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    Mandal, C. C., Ganapathy, S., Gorin, Y., Mahadev, K., Block, K., Abboud, H. E., Harris, S. E., Ghosh-Choudhury, G., & Ghosh-Choudhury, N. (2011). Reactive oxygen species derived from Nox4 mediate BMP2 gene transcription and osteoblast differentiation. Biochemical Journal, 433(2), 393-402. https://doi.org/10.1042/BJ20100357