Hall Susan L, Chen Shin-Tai, Gysin Reinhard, Gridley Daila S, Mohan Subburaman, Lau K-H William
Musculoskeletal Disease Center (151), Jerry L. Pettis Memorial VA Medical Center, 11201 Benton Street, Loma Linda, California 92357, USA.
J Gene Med. 2009 Oct;11(10):877-88. doi: 10.1002/jgm.1369.
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.
Sublethally irradiated recipient mice were transplanted with lentiviral (LV)-BMP2/4-transduced Sca-1+ cells. Bone parameters were monitored by pQCT and microCT. Gene expression was assessed by the real-time reverse transcriptase-polymerase chain reaction.
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 microCT 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.
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.
本研究评估了一种基于Sca-1+细胞的体外基因转移策略，该策略已被证明可通过修饰的成纤维细胞生长因子-2（FGF2）基因促进强大的骨内膜骨形成，是否可扩展用于骨形态发生蛋白（BMP）2/4杂交基因。
对接受亚致死剂量照射的受体小鼠移植慢病毒（LV）-BMP2/4转导的Sca-1+细胞。通过外周定量计算机断层扫描（pQCT）和显微计算机断层扫描（microCT）监测骨参数。通过实时逆转录聚合酶链反应评估基因表达。
LV-BMP2/4转导的Sca-1+细胞的受体小鼠具有高植入率，且骨髓细胞中BMP4 mRNA水平升高；但与对照小鼠相比，血清和骨碱性磷酸酶活性仅略有增加。对股骨的pQCT和microCT分析表明，除LV-BMP2/4小鼠的小梁骨矿物质密度和皮质骨矿物质含量有微小变化外，LV-BMP2/4组小鼠与对照组小鼠的测量骨参数无差异。BMP4策略缺乏大的骨内膜骨形成效应，这不能归因于表达BMP4的Sca-1+细胞植入无效或扩增不足、转导细胞无法分泌活性BMP4蛋白或使用基于LV的载体。
基于Sca-1+细胞的BMP4体外策略未促进强大的骨内膜骨形成，这增加了基于FGF2和BMP4的策略在促进骨内膜骨形成能力方面存在内在差异的可能性。这强调了选择合适的骨生长因子基因通过这种基于Sca-1+细胞的体外全身基因转移策略来促进骨形成的重要性。
