title: Osteogenic differentiation of human mesenchymal stem cells through alginate-graft-poly(ethylene glycol) microsphere-mediated intracellular growth factor delivery.
abstract: The intracellular delivery of growth factors increases opportunities for controlling cell behavior and maintaining tissue homeostasis. Recently, VEGFA was reported to enhance osteogenic differentiation of mesenchymal stem cells (MSCs) through an intracrine mechanism, suggesting a new strategy to promote bone tissue formation in osteoporotic patients. The goal of this study was to design and fabricate ligand-conjugated alginate-graft-poly(ethylene glycol) microspheres for intracellular delivery and release of VEGFA in primary human MSCs to enhance osteogenic differentiation as a potential therapeutic. Three types of microspheres were synthesized and characterized by scanning electron microscopy, in vitro drug release kinetics, MSC uptake and internalization: alginate alone (Alg), alginate-graft-poly(ethylene glycol) (Alg-g-PEG) and alginate-graft-poly(ethylene glycol)-S-S-arginine-glycine-aspartic acid (Alg-g-RGD). Each of the different microsphere formulations successfully transported bioactive VEGFA into primary human MSCs within 48h of culture, and significantly enhanced osteogenic differentiation compared to control treatments with empty microspheres (intracellular control) or non-encapsulated VEGFA (extracellular control). Adipogenic differentiation was not affected by the presence of VEGFA intracellularly or extracellularly. These results demonstrating the internalization of alginate-based microspheres and intracellular delivery of VEGFA support the efficacy of using this drug delivery and intracrine mechanism to control the fate of human MSCs and enhance osteogenic differentiation.
authors: Bioengineering Program, College of Engineering and Mathematical Sciences, College of Medicine, University of Vermont, Burlington VT 05405, USA. Electronic address: tmiao@uvm.edu.
authors: Tianxin
authors: T
authors: Miao
authors: Cell and Molecular Biology Graduate Program, College of Medicine, University of Vermont, Burlington, VT 05405, USA. Electronic address: krao@uvm.edu.
authors: Krithika S
authors: KS
authors: Rao
authors: Cell and Molecular Biology Graduate Program, College of Medicine, University of Vermont, Burlington, VT 05405, USA; Stem Cell Core, University of Vermont, Colchester, VT 05446, USA. Electronic address: jspees@uvm.edu.
authors: Jeffrey L
authors: JL
authors: Spees
authors: Bioengineering Program, College of Engineering and Mathematical Sciences, College of Medicine, University of Vermont, Burlington VT 05405, USA; Mechanical Engineering Program, College of Engineering and Mathematical Sciences, University of Vermont, Burlington, VT 05405, USA; Department of Orthopaedics and Rehabilitation, College of Medicine, University of Vermont, Burlington, VT 05405, USA. Electronic address: oldinski@uvm.edu.
authors: Rachael A
authors: RA
authors: Oldinski
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002454:Cell Differentiation; D002478:Cells, Cultured; D016503:Drug Delivery Systems; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D008863:Microspheres; D010012:Osteogenesis / Q000187:drug effects*; D011092:Polyethylene Glycols / Q000737:chemistry*; D042461:Vascular Endothelial Growth Factor A / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D011092:Polyethylene Glycols; D020723:Glucuronic Acid
keywords: Alginate; Growth factor delivery; Mesenchymal stem cells; Microspheres; Poly(ethylene glycol); RGD