Stem cell antigen-1+ cell-based bone morphogenetic protein-4 gene transfer strategy in mice failed to promote endosteal bone formation

✍ Scribed by Susan L. Hall; Shin-Tai Chen; Reinhard Gysin; Daila S. Gridley; Subburaman Mohan; K.-H. William Lau

• Book ID: 102339764
• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 255 KB
• Volume: 11
• Category: Article
• ISSN: 1099-498X
• DOI: 10.1002/jgm.1369

✦ Synopsis

Abstract

Background

This study assessed whether a Sca‐1^+^ cell‐based ex vivo gene transfer strategy, which has been shown to promote robust endosteal bone formation with a modified fibroblast growth factor‐2 (FGF2) gene, can be extended to use with bone morphogenetic protein (BMP)2/4 hybrid gene.

Methods

Sublethally irradiated recipient mice were transplanted with lentiviral (LV)‐BMP2/4‐transduced Sca‐1^+^ cells. Bone parameters were monitored by pQCT and µCT. Gene expression was assessed by the real‐time reverse transcriptase‐polymerase chain reaction.

Results

Recipient mice of LV‐BMP2/4‐transduced Sca‐1^+^ cells yielded high engraftment and increased BMP4 mRNA levels in marrow cells; but exhibited only insignificant increases in serum and bone alkaline phosphatase activity compared to control mice. pQCT and µCT analyses of femurs showed that, with the exception of small changes in trabecular bone mineral density and cortical bone mineral content in LV‐BMP2/4 mice, there were no differences in measured bone parameters between mice of the LV‐BMP2/4 group and controls. The lack of large endosteal bone formation effects with the BMP4 strategy could not be attributed to ineffective engraftment or expansion of BMP4‐expressing Sca‐1^+^ cells, an inability of the transduced cells to secrete active BMP4 proteins, or to use of the LV‐based vector.

Conclusions

Sca‐1^+^ cell‐based BMP4 ex vivo strategy did not promote robust endosteal bone formation, raising the possibility of intrinsic differences between FGF2‐ and BMP4‐based strategies in their ability to promote endosteal bone formation. It emphasizes the importance of choosing an appropriate bone growth factor gene for delivery by this Sca‐1^+^ cell‐based ex vivo systemic gene transfer strategy to promote bone formation. Copyright © 2009 John Wiley & Sons, Ltd.