Cell-cell interactions of human neural progenitor-derived astrocytes within a microstructured 3D-scaffold.

In the present in vitro study, the axon growth promoting effects of human neural progenitor-derived astrocytes (hNP-AC) were investigated in simple 2D- as well as in more complex 3D-culture systems. The interactions of the hNP-AC with migrating Schwann cells and fibroblasts were also studied. hNP-AC were found to promote extensive dorsal root ganglion axon regeneration in 2D cultures, being even greater than that observed on the positive control, laminin-coated substrate. Contact-mediated mechanisms and the release of substances into the medium both played a role in supporting axon regeneration. Following seeding onto 3D collagen scaffolds, hNP-AC also promoted significantly greater axon regeneration from DRG explants than was seen on non-seeded scaffolds. The highly orientated, porous microstructure of the scaffold also supported substantial intermixing of hNP-AC and migrating Schwann cells/fibroblasts from the DRG explant, cell populations that are normally mutually repulsive. This suggests that the topography of 3D scaffolds may not only influence cell-substrate interactions but also cell-cell interactions within the scaffold. This opens the possibility that the design of future scaffolds could be optimised to enhance cell integration as well as modulating complex cell-cell interactions.