Induction of Bone Formation by 3D Biologically Active Scaffolds Containing RGD‐NPs, BMP2, and NtMPCs

Abstract

AbstractIt is demonstrated that nuclear transfer embryonic stem cells (NT‐ESCs) can be transformed into mesenchymal progenitor cells (NtMPCs) via culture under appropriate conditions and it is proposed that NtMPCs can be used for bone regeneration instead of bone marrow‐derived mesenchymal stem cells (BMSCs). In a 2‐dimensional culture, NtMPCs undergo chondrogenic and adipogenic differentiation more readily than BMSCs upon culture in appropriate media. However, the osteogenic differentiation ability of NtMPCs is lower than that of BMSCs. 3‐dimensional (3D) biologically active scaffolds (BAs) comprising poly(lactic‐co‐glycolic acid) (PLGA) microspheres are constructed to improve osteogenic differentiation. To generate BAs, nanoparticles containing an l‐Arginyl‐Glycyl‐l‐Aspartic acid (RGD) sequence (RGD‐NPs) and dexamethasone (DEX), a drug used to control differentiation and inflammation, are simultaneously encapsulated by PLGA to form particles measuring 150–250 µm. After that, bone morphogenetic protein 2 (BMP2) is immobilized on the surface of polyethylenimine (PEI)‐coated microspheres via formation of ionic bonds between O‐sulfate and N‐sulfate in heparin with lysine/arginine residues of BMP2. Gene expression profiling is performed via QuantSeq 3′ mRNA‐sequencing in mice transplanted with BAs containing NtMPCs and BMSCs. Expression of the osteogenic differentiation‐related genes collagen Type I Alpha 2 (COL1A2), Homeobox protein MSX‐2 (MSX2), Runt‐related transcription factor 2 (RUNX2), and bone morphogenetic protein 2 (BMP2) is 2–3‐fold higher in mice transplanted with BAs containing NtMPCs than in mice transplanted with BAs containing BMSCs.