Raftery, RM, Mencía-Castaño, I, Sperger, S et al. (6 more authors) (2018) Delivery of the improved BMP-2-Advanced plasmid DNA within a gene-activated scaffold accelerates mesenchymal stem cell osteogenesis and critical size defect repair. Journal of Controlled Release, 283. pp. 20-31. ISSN 0168-3659
Abstract
Gene-activated scaffolds have been shown to induce controlled, sustained release of functional transgene both in vitro and in vivo. Bone morphogenetic proteins (BMPs) are potent mediators of osteogenesis however we found that the delivery of plasmid BMP-2 (pBMP-2) alone was not sufficient to enhance bone formation. Therefore, the aim of this study was to assess if the use of a series of modified BMP-2 plasmids could enhance the functionality of a pBMP-2 gene-activated scaffold and ultimately improve bone regeneration when implanted into a critical sized bone defect in vivo. A multi-cistronic plasmid encoding both BMP-2 and BMP-7 (BMP-2/7) was employed as was a BMP-2-Advanced plasmid containing a highly truncated intron sequence. With both plasmids, the highly efficient cytomegalovirus (CMV) promoter sequence was used. However, as there have been reports that the elongated factor 1-α promoter is more efficient, particularly in stem cells, a BMP-2-Advanced plasmid containing the EF1α promoter was also tested. Chitosan nanoparticles (CS) were used to deliver each plasmid to MSCs and induced transient up-regulation of BMP-2 protein expression, in turn significantly enhancing MSC-mediated osteogenesis when compared to untreated controls (p < 0.001). When incorporated into a bone mimicking collagen-hydroxyapatite scaffold, the BMP-2-Advanced plasmid, under the control of the CMV promotor, induced MSCs to produce approximately 2500 μg of calcium per scaffold, significantly higher (p < 0.001) than all other groups. Just 4 weeks post-implantation in vivo, this cell-free gene-activated scaffold induced significantly more bone tissue formation compared to a pBMP-2 gene-activated scaffold (p < 0.001) as indicated by microCT and histomorphometry. Immunohistochemistry revealed that the BMP-2-Advanced plasmid accelerated differentiation of osteoprogenitor cells to mature osteoblasts, thus causing rapid healing of the bone defects. This study confirms that optimising the plasmid construct can enhance the functionality of gene-activated scaffolds and translate to accelerated bone formation in a critical sized defect.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2018 Elsevier B.V. This is an author produced version of a paper published in the Journal of Controlled Release. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | BMP-2; Plasmid; Gene delivery; Gene-activated scaffold; Osteogenesis; Bone regeneration |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Medicine and Health (Leeds) > School of Dentistry (Leeds) > Oral Biology (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 06 Jun 2018 10:05 |
Last Modified: | 19 May 2019 00:41 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.jconrel.2018.05.022 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:131677 |
Download
Filename: Delivery of the improved BMP-2-Advanced plasmid DNA.pdf
Licence: CC-BY-NC-ND 4.0