The repair of bone tissue injuries, especially those occurring in the craniofacial region, is a significant challenge in orthopaedics. There are currently few effective treatments available for these injuries. Tissue engineering seeks to repairor replace the damaged tissue by encouraging regeneration of the host tissue through provision of the necessary biochemical, cellular, and mechanical cues. Human mesenchymal stem cells (hMSCs) are a promising cell source for bone regeneration as they are capable of differentiating into osteogenic tissue, are easily obtainable from bone marrow, and can proliferate in culture readily so that it is possible to obtain a sufficient number of cells for tissue engineering approaches. RNA interference is a powerful gene silencing mechanism that inhibits gene expression at the translational level by the targeted destruction of specific mRNA molecules, and has the potential to revolutionize disease treatment and aid in the functional repair of damaged tissue by decreasing the expression of specific proteins. Additionally, the potential for delivering short interfering RNA (siRNA) to stem cells to direct their differentiation to promote the desired tissue growth is exciting. However, effectively delivering bioactive siRNA to damaged tissue sites remains a challenge, and more research is needed to determine its effectiveness in the differentiation of hMSCs and enhancement of resultant tissue formation. Thus, this proposed work seeks to engineer novel biomaterial systems for controlled and sustained delivery of siRNA and to examine the effect of delivering siRNA against BMP antagonists on the osteogenic diferentiation of hMSCs and bone formation. The central hypothesis is that silencing the expression of BMP antagonists via controlled delivery of siRNA will promote the osteogenic response of hMSCs, and enhance bone regeneration. This will be addressed by the following specific aims: (1) engineer novel biopolymer hydrogels capable of releasing siRNA in a sustained and controllable manner over time, (2) deliver siRNA against a BMP antagonist from biopolymer hydrogels and investigate its effect on guiding encapsulated and surrounding hMSCs down the osteogenic lineage and (3) assess the ability of the system to drive bone formation in vivo upon implantation of hydrogel constructs containing siRNA and hMSCs into a critical-size bone defect. This proposal aims to demonstrate the utility of a new approach to improve the repair of bony defects, which would have great clinical benefit, in addition to creating a platform technology that could then be used for other therapeutic applications.

Public Health Relevance

Treating bone defects incurred by mililons of Americans each year, especially those occurring in the craniofacial region, remains a significant chalenge to the orthopaedics community as there are few viable options for those that exhibit problematic healing. We propose to engineer biopolymer systems for the delivery of siRNA to mesenchymal stem cells to silence the expresion of bone morphogenetic protein (BMP) antagonists and thereby increase their osteogenic response. The results from this proposal will represent a significant advance for osteogenic tissue regeneration for healing bone defects, provide an increased understanding of stem cell diferentiation decision pathways, and lead to the development of a platform technology for the effective delivery of siRNA that may hold promise for many applications in regenerative and therapeutic medicine.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
High Priority, Short Term Project Award (R56)
Project #
1R56DE022376-01A1
Application #
8521781
Study Section
Musculoskeletal Tissue Engineering Study Section (MTE)
Program Officer
Lumelsky, Nadya L
Project Start
2012-08-09
Project End
2014-07-31
Budget Start
2012-08-09
Budget End
2014-07-31
Support Year
1
Fiscal Year
2012
Total Cost
$345,969
Indirect Cost
$120,969
Name
Case Western Reserve University
Department
Biomedical Engineering
Type
Schools of Engineering
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106
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Samorezov, Julia E; Alsberg, Eben (2015) Spatial regulation of controlled bioactive factor delivery for bone tissue engineering. Adv Drug Deliv Rev 84:45-67
Hill, Michael C; Nguyen, Minh K; Jeon, Oju et al. (2015) Spatial control of cell gene expression by siRNA gradients in biodegradable hydrogels. Adv Healthc Mater 4:714-22
Jeon, Oju; Wolfson, David W; Alsberg, Eben (2015) In-situ formation of growth-factor-loaded coacervate microparticle-embedded hydrogels for directing encapsulated stem cell fate. Adv Mater 27:2216-23
Samorezov, Julia E; Morlock, Colin M; Alsberg, Eben (2015) Dual Ionic and Photo-Crosslinked Alginate Hydrogels for Micropatterned Spatial Control of Material Properties and Cell Behavior. Bioconjug Chem 26:1339-47
Nguyen, Minh Khanh; Alsberg, Eben (2014) Bioactive factor delivery strategies from engineered polymer hydrogels for therapeutic medicine. Prog Polym Sci 39:1236-1265
Cheng, Christina W; Solorio, Loran D; Alsberg, Eben (2014) Decellularized tissue and cell-derived extracellular matrices as scaffolds for orthopaedic tissue engineering. Biotechnol Adv 32:462-84
Nguyen, Minh K; Jeon, Oju; Krebs, Melissa D et al. (2014) Sustained localized presentation of RNA interfering molecules from in situ forming hydrogels to guide stem cell osteogenic differentiation. Biomaterials 35:6278-86
Jeon, Oju; Alsberg, Eben (2013) Regulation of Stem Cell Fate in a Three-Dimensional Micropatterned Dual-Crosslinked Hydrogel System. Adv Funct Mater 23:4765-4775
Jeon, Oju; Alsberg, Eben (2013) Photofunctionalization of alginate hydrogels to promote adhesion and proliferation of human mesenchymal stem cells. Tissue Eng Part A 19:1424-32

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