Calcified Tissue International

, 85:356

Marrow Stromal Cell-Based Cyclooxygenase 2 Ex Vivo Gene-Transfer Strategy Surprisingly Lacks Bone-Regeneration Effects and Suppresses the Bone-Regeneration Action of Bone Morphogenetic Protein 4 in a Mouse Critical-Sized Calvarial Defect Model

  • K.-H. William Lau
  • Reinhard Gysin
  • Shin-Tai Chen
  • Jon E. Wergedal
  • David J. Baylink
  • Subburaman Mohan
Article

DOI: 10.1007/s00223-009-9282-2

Cite this article as:
Lau, KH.W., Gysin, R., Chen, ST. et al. Calcif Tissue Int (2009) 85: 356. doi:10.1007/s00223-009-9282-2

Abstract

This study evaluated whether the murine leukemia virus (MLV)–based cyclooxygenase-2 (Cox-2) ex vivo gene-transfer strategy promotes healing of calvarial defects and/or synergistically enhances bone morphogenetic protein (BMP) 4–mediated bone regeneration. Gelatin scaffolds impregnated with mouse marrow stromal cells (MSCs) transduced with MLV-expressing BMP4, Cox-2, or a control gene were implanted into mouse calvarial defects. Bone regeneration was assessed by X-ray, dual-energy X-ray absorptiometry, and histology. In vitro, Cox-2 or prostanglandin E2 enhanced synergistically the osteoblastic differentiation action of BMP4 in mouse MSCs. In vivo, implantation of BMP4-expressing MSCs yielded massive bone regeneration in calvarial defects after 2 weeks, but the Cox-2 strategy surprisingly did not promote bone regeneration even after 4 weeks. Staining for alkaline phosphatase (ALP)–expressing osteoblasts was strong throughout the defect of animals receiving BMP2/4-expressing cells, but defects receiving Cox-2-expressing cells displayed weak ALP staining along the edge of original intact bone, indicating that the Cox-2 strategy lacked bone-regeneration effects. The Cox-2 strategy not only lacked bone-regeneration effects but also suppressed the BMP4-induced bone regeneration. In vitro coculture of Cox-2-expressing MSCs with BMP4-expressing MSCs in gelatin scaffolds reduced BMP4 mRNA transcript levels, suggesting that Cox-2 may promote BMP4 gene silencing in BMP4-expressing cells, which may play a role in the suppressive action of Cox-2 on BMP4-mediated bone formation. In summary, the Cox-2 ex vivo gene-transfer strategy not only lacks bone-regeneration effects but also suppresses the bone-regeneration action of BMP4 in healing of calvarial defects.

Keywords

Bone morphogenetic protein 4 Cyclooxygenase 2 Marrow stromal cell Calvarial defect Bone regeneration Gene therapy Ex vivo Mice 

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • K.-H. William Lau
    • 1
    • 2
    • 3
  • Reinhard Gysin
    • 1
    • 2
  • Shin-Tai Chen
    • 1
    • 2
    • 3
  • Jon E. Wergedal
    • 1
    • 2
    • 3
  • David J. Baylink
    • 2
  • Subburaman Mohan
    • 1
    • 2
    • 3
    • 4
  1. 1.Musculoskeletal Disease Center (151)Jerry L. Pettis Memorial VA Medical CenterLoma LindaUSA
  2. 2.Department of MedicineLoma Linda University School of MedicineLoma LindaUSA
  3. 3.Department of BiochemistryLoma Linda University School of MedicineLoma LindaUSA
  4. 4.Department of PhysiologyLoma Linda University School of MedicineLoma LindaUSA

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