Carbon nanotube–collagen three-dimensional culture of mesenchymal stem cells promotes expression of neural phenotypes and secretion of neurotrophic factors

• Published in: Acta biomaterialia 2014-10, Vol.10 (10), p.4425-4436
• Main Authors: Lee, Jae Ho, Lee, Ja-Yeon, Yang, Sung Hee, Lee, Eun-Jung, Kim, Hae-Won
• Format: Article
• Language: English
• Subjects: Animals; Antigens, Differentiation - biosynthesis; Brain-Derived Neurotrophic Factor - biosynthesis; Carbon nanotubes; Cells, Cultured; Collagen - chemistry; Collagen hydrogel; Collagens; GAP-43 Protein - biosynthesis; Gene Expression Regulation; Hydrogels; Hydrogels - chemistry; Male; Markers; Mathematical models; Mesenchymal stem cells; Mesenchymal Stromal Cells - cytology; Mesenchymal Stromal Cells - metabolism; Nanostructure; Nanotubes, Carbon - chemistry; Neural regeneration; Neurotrophic factors; PC12 Cells; Rats; Rats, Sprague-Dawley; Secretions; Stem cells; Three dimensional; Tubulin - biosynthesis
• ISSN: 1742-7061; 1878-7568
• DOI: 10.1016/j.actbio.2014.06.023

CNT-incorporated collagen gels provide 3D matrix environments for MSCs to express neural phenotypes and to secrete neurotrophic factors, proposing a novel approach of cell-matrix system for neural therapies. [Display omitted] Microenvironments provided by three-dimensional (3-D) hydrogels mimic native tissue conditions, supplying appropriate physical cues for regulating stem cell behaviors. Here, we focused on carbon nanotubes (CNTs) dispersed within collagen hydrogels to provide 3-D microenvironmental conditions for mesenchymal stem cells (MSCs) in stimulating biological functions for neural regeneration. Small concentrations of CNTs (0.1–1wt.%) did not induce toxicity to MSCs, and even improved the proliferative potential of the cells. MSCs cultured within the CNT–collagen hydrogel expressed considerable levels of neural markers, including GAP43 and βIII tubulin proteins by immunostaining as well as GAP43 and synapse I genes by reverse transcriptase polymerase chain reaction (RT-PCR). Of note was that neurotrophic factors, particularly nerve growth factor and brain derived neurotrophic factor, were significantly promoted by the incorporation of CNTs as confirmed by RT-PCR and Western blot analysis. A model experiment involving neuritogenesis of PC12 cells influenced by those releasing neurotrophic factors from MSCs cultured within the CNT–collagen hydrogel demonstrated the significant enhancement in neurite outgrowth behaviors. Taken together, collagen hydrogel provides excellent 3-D conditions for MSC growth, and a small incorporation of CNTs within the hydrogel significantly stimulates MSC expression of neural markers and secretion of neurotrophic factors.