Local administration of AAV-DJ pseudoserotype expressing COX2 provided early onset of transgene expression and promoted bone fracture healing in mice
Local administration of AAV-DJ pseudoserotype expressing COX2 provided early onset of transgene expression and promoted bone fracture healing in mice
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DOI：
10.1038/gt.2015.40
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发表时间：
2015-09-01
期刊：
影响因子：
5.1
通讯作者：
Qin, X.
中科院分区：
文献类型：
--
作者：
Lakhan, R.;Baylink, D. J.;Qin, X.
我们之前已经获得了令人信服的原则证据，证明了使用整合的逆转录病毒载体进行COX2基因治疗用于骨折修复。为了使这种疗法适合患者使用，必须使用具有高安全性的合适的媒介。因此，这项研究试图评估AAV作为COX2基因治疗载体的可行性，因为AAV比以前使用的逆转录病毒载体引起的安全问题更少。然而，需要适当的AAV血清型来提供骨折修复所需的早期增加和足够水平的COX2表达。在此，我们报道了AAV-DJ，一种人工AAV假型，在小鼠股骨骨折模型中高效地将COX2基因转移到骨折部位。与AAV-2相比，AAV-DJ的使用使间充质干细胞(MSCs)的感染性增加了近5倍，并在骨折部位提供了更早和更高水平的转基因表达。X线片和MU-CT分析显示，以7.5×10(11)个基因组拷贝的剂量注射该载体后第3天，骨折处COX2水平升高，第21天时显著促进骨折愈合。治疗效果似乎涉及促进MSCs的成骨分化和骨痂组织向板层骨的重塑。这一解释得到了参与骨折修复过程的几个关键基因表达增强的支持。综上所述，AAV-DJ是以AAV为基础的COX2基因治疗人类骨折修复的一种很有前景的血清型。
We have previously obtained compelling proof-of-principle evidence for COX2 gene therapy for fracture repair using integrating retroviral vectors. For this therapy to be suitable for patient uses, a suitable vector with high safety profile must be used. Accordingly, this study sought to evaluate the feasibility of AAV as the vector for this COX2 gene therapy, because AAV raises less safety issues than the retroviral vectors used previously. However, an appropriate AAV serotype is required to provide early increase in and adequate level of COX2 expression that is needed for fracture repair. Herein, we reported that AAV-DJ, an artificial AAV pseudoserotype, is highly effective in delivering COX2 gene to fracture sites in a mouse femoral fracture model. Compared with AAV-2, the use of AAV-DJ led to similar to 5-fold increase in infectivity in mesenchymal stem cells (MSCs) and provided an earlier and significantly higher level of transgene expression at the fracture site. Injection of this vector at a dose of 7.5 x 10(11) genomic copies led to high COX2 level at the fracture site on day 3 after injections and significantly promoted fracture union at 21 days, as analyzed by radiography and mu-CT. The therapeutic effect appears to involve enhanced osteoblastic differentiation of MSCs and remodeling of callus tissues to laminar bone. This interpretation is supported by the enhanced expression of several key genes participating in the fracture repair process. In conclusion, AAV-DJ is a promising serotype for the AAV-based COX2 gene therapy of fracture repair in humans.