Chondrogenic differentiation of human mesenchymal stem cell aggregates via controlled release of TGF‐β1 from incorporated polymer microspheres

Abstract

Aggregate culture is a useful method for inducing chondrogenic differentiation of human mesenchymal stem cells (hMSC) in a three-dimensional in vitro culture environment. Conventional aggregate culture, however, typically requires repeated growth factor supplementation during media changes, which is both expensive and time-intensive. In addition, homogenous cell differentiation is limited by the diffusion of chondrogenic growth factor from the culture medium into the aggregate and peripheral cell consumption of the growth factor. We have engineered a technology to incorporate growth factor-loaded polymer microspheres within hMSC aggregates themselves. Here, we report on the system’s capacity to induce chondrogenesis via sustained delivery of transforming growth factor-b1 (TGF-β1). Cartilage formation after 3 weeks in the absence of externally supplied growth factor approached that of aggregates cultured by conventional methods. Chondrogenesis in the central region of the aggregates is enabled at TGF-β1 levels much lower than those required by conventional culture using exogenously supplied TGF-β1, which is likely a result of the system’s ability to overcome limitations of growth factor diffusion from cell culture media surrounding the exterior of the aggregates. Importantly, the inclusion of growth factor-releasing polymer microspheres in hMSC aggregates could enable in vivo chondrogenesis for cartilage tissue engineering applications without extensive in vitro culture.

MicroRNA Levels as Prognostic Markers for the Differentiation Potential of Human Mesenchymal Stromal Cell Donors

“…It is plausible that differences in TGFb responsiveness of hMSC donors might lead to distinct chondrogenic performance of hMSCs. Indeed, exogenous supplementation of TGFb is a main driver of chondrogenic differentiation in hMSC pellet cultures [38]. In addition, TGFb is a key upstream regulator of AP-1 activity through its downstream effectors SMAD2 and SMAD3 [39].…”

The Multiparametric Effects of Hydrodynamic Environments on Stem Cell Culture

“…Microspheres have been incorporated within stem cell aggregates, enabling delivery of morphogens more homogeneously throughout the multicellular microenvironment. 104,[141][142][143][144][145] The combination of the hydrodynamic culture environment with microsphere-mediated delivery may enable analysis of the impact of fluid shear on cell spheroids, independent of small molecule and growth factor transport limitations. Additionally, combinatorial methods for simultaneously controlling morphogen delivery and the hydrodynamic environment could lead to synergistic methods to more efficiently and effectively direct stem cell differentiation.…”

Transforming growth factor‐β in liver cancer stem cells and regeneration

“…5), through cross‐talk involving the Smad pathway, non‐Smad pathways including MAP kinase pathways, PI3K/AKT pathways, and Rho‐like GTPase signaling pathways. For instance, TGF‐β promotes the differentiation of stem cells into smooth muscle cells,34, 35, 36, 37 chondrocytes,38, 39, 40 neurocytes, hepatic stellate cells, Th17 cells, dendritic cells, and cardiomyocytes 41. However, TGF‐β inhibits the differentiation of stem cells into myotubes,42 adipocytes, endothelial cells, and natural killer cells 41.…”