Instructive nanofibrous scaffold comprising runt-related transcription factor 2 gene delivery for bone tissue engineering

"Epub 2014 Jul. 30"Inducer molecules capable of regulating mesenchymal stem cells (MSCs) differentiation into specific lineages have proven effective in basic science and in preclinical studies. Runt-related transcription factor 2 (RUNX2) is considered to be the central gene involved in the osteoblast phenotype induction, which may be advantageous for inducing bone tissue regeneration. This work envisions the development of a platform for gene delivery, combining liposomes as gene delivery devices, with electrospun nanofiber mesh (NFM) as a tissue engineering scaffold. pDNA-loaded liposomes were immobilized at the surface of functionalized PCL NFM. Human bone marrow-derived mesenchymal stem cells (hBMSCs) cultured on RUNX2-loaded liposomes immobilized at the surface of electrospun PCL NFM showed enhanced levels of metabolic activity and total protein synthesis. RUNX2-loaded liposomes immobilized at the surface of electrospun PCL NFMs induce a long-term gene expression of eGFP and RUNX2 by cultured hBMSCs. Furthermore, osteogenic differentiation of hBMSCs was also achieved by the overexpression of other osteogenic markers in medium free of osteogenic supplementation. These findings demonstrate that surface immobilization of RUNX2 plasmid onto elestrospun PCL NFM can produce long-term gene expression in vitro, which may be employed to enhance the osteoinductive properties of scaffolds used for bone tissue engineering strategies.The authors thank the Portuguese Foundation for Science and Technology for the PhD grant of N.M. (SFRH/BD/62465/2009), and the Post-Doc grants of A.M. (SFRH/BPD/70669/2010), and the OsteoGraphy project (PTDC/EME-MFE/2008). This work was partly supported by the POLARIS (FP7-REGPOT-2012-2013-1), MaxBone (PTDC/SAU -ENB/115179/2009), and RL3-TECT-NORTE-01-0124-FEDER-000020, co-financed by North Portugal Regional Operational Programme (ON.2 - O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF) projects