Runx2/Cbfa1 stimulates transdifferentiation of primary skeletal myoblasts into a mineralizing osteoblastic phenotype.

Journal Article

Runx2, a transcriptional activator downstream of bone morphogenetic protein (BMP) signaling, is essential to osteoblastic differentiation and bone formation and maintenance. BMPs activate complex signaling networks, utilizing numerous signaling molecules and transcription factors to induce expression of osteoblastic markers in mesenchymal cell types. However, the role of Runx2 in this process, particularly in an environment independent of the other regulatory elements modulated by BMPs, remains poorly understood. In the present study, we used retroviral gene delivery to examine the effects of sustained Runx2 expression in primary myoblasts. Runx2 inhibited myogenesis, as demonstrated by suppression of MyoD and myogenin mRNA levels and reduced myotube formation. Additionally, Runx2-stimulated osteogenesis including osteoblastic gene expression, alkaline phosphatase activity, and biological mineral deposition. Notably, these osteogenic markers were induced to significantly greater levels than those observed in BMP-2-treated controls. These results demonstrate that direct exogenous expression of the Runx2 transcription factor, only one of numerous downstream targets of BMP signaling, is sufficient to induce transdifferentiation of myogenic cells into a mineralizing osteogenic lineage. This work underscores the potency of Runx2 as a regulator of osteogenesis and cell differentiation and provides new insights into the plasticity of committed mesenchymal cells.

Full Text

Duke Authors

Cited Authors

  • Gersbach, CA; Byers, BA; Pavlath, GK; García, AJ

Published Date

  • November 1, 2004

Published In

Volume / Issue

  • 300 / 2

Start / End Page

  • 406 - 417

PubMed ID

  • 15475005

International Standard Serial Number (ISSN)

  • 0014-4827

Digital Object Identifier (DOI)

  • 10.1016/j.yexcr.2004.07.031

Language

  • eng

Conference Location

  • United States