Inducible regulation of Runx2-stimulated osteogenesis.

Journal Article (Journal Article)

Ex vivo gene therapy is a promising approach to orthopedic regenerative medicine. These strategies typically focus on the constitutive overexpression of osteogenic factors to induce osteoblastic differentiation and matrix mineralization. However, the unregulated production of osteoinductive molecules has also resulted in abnormal bone formation and tumorigenesis. To address these limitations, this work describes a retroviral system to deliver the Runx2 osteoblastic transcription factor under control of the tetracycline-inducible (tet-off) promoter in primary skeletal myoblasts. Runx2 expression was tightly regulated by anhydrotetracyline (aTc) concentration in cell culture media. Osteoblastic gene expression, alkaline phosphatase activity, and matrix mineralization were also controlled by aTc in a dose-dependent manner. Additionally, osteoblastic differentiation was temporally regulated by adding and removing aTc from the culture media. Engineered cells were seeded onto collagen scaffolds and implanted intramuscularly in the hind limbs of syngeneic mice. In vivo mineralization by these constructs was regulated by supplementing the drinking water with aTc, as demonstrated by micro-computed tomography and histological analyses. Collectively, these results present a novel system for regulating osteoblastic differentiation of a clinically relevant autologous cell source. This system is significant to developing controlled and effective orthopedic gene therapy strategies and studying the regulation of osteoblastic differentiation.

Full Text

Duke Authors

Cited Authors

  • Gersbach, CA; Le Doux, JM; Guldberg, RE; García, AJ

Published Date

  • June 2006

Published In

Volume / Issue

  • 13 / 11

Start / End Page

  • 873 - 882

PubMed ID

  • 16496016

Electronic International Standard Serial Number (EISSN)

  • 1476-5462

International Standard Serial Number (ISSN)

  • 0969-7128

Digital Object Identifier (DOI)

  • 10.1038/


  • eng