Human Adipose-Derived Mesenchymal Stem Cells: Direction to a Phenotype Sharing Similarities with the Disc, Gene Expression Profiling, and Coculture with Human Annulus Cells

Biologic therapies for disc degeneration hold great promise as an emerging concept. Due to ease of harvest and abundance, adipose derived-mesenchymal stem cells (AD-MSC) are a readily available cell source for such therapies. Our objectives in this study were (1) to develop/validate methods to harvest AD-MSC and direct them to a disc-like phenotype by three-dimensional (3D) culture and transforming growth factor (TGF)-beta 3 exposure, (2) to assess cell phenotypes with gene expression profiling for these human AD-MSC and annulus cells, and (3) to test whether disc cell-AD-MSC coculture could augment glycosaminoglycan (GAG) production. When AD-MSC were exposed to TGF-beta 3, greater extracellular matrix was formed containing types I and II collagen, keratan sulfate, and decorin. Biochemical GAG measurement showed that production was significantly greater in TGF-beta 3- treated AD-MSC in 3D culture versus untreated controls (p<0.05). Gene expression patterns in AD-MSC were compared to annulus cells; 4424 genes were significantly upregulated, and 2290 genes downregulated. Coculture resulted in a 44% greater GAG content compared with AD-MSC or annulus culture alone (p-0.04). Data indicated that human AD-MSC can successfully be manipulated in 3D culture to express gene products important in the disc, and that coculture of annulus cells with AD-MSC enhances total GAG production.