A role for neuropilins in the interaction between Schwann cells and meningeal cells

SDF-1α gene-activated collagen scaffold enhances provasculogenic response in a coculture of human endothelial cells with human adipose-derived stromal cells

Novel biomaterials can be used to provide a better environment for cross talk between vessel forming endothelial cells and wound healing instructor stem cells for tissue regeneration. This study seeks to investigate if a collagen scaffold containing a proangiogenic gene encoding for the chemokine stromal-derived factor-1 alpha (SDF-1α GAS) could be used to enhance functional responses in a coculture of human umbilical vein endothelial cells (HUVECs) and human adipose-derived stem/stromal cells (ADSCs). Functional responses were determined by (1) monitoring the amount of junctional adhesion molecule VE-cadherin released during 14 days culture, (2) expression of provasculogenic genes on the 14th day, and (3) the bioactivity of secreted factors on neurogenic human Schwann cells. When we compared our SDF-1α GAS with a gene-free scaffold, the results showed positive proangiogenic determination characterized by a transient yet controlled release of the VE-cadherin. On the 14th day, the coculture on the SDF-1α GAS showed enhanced maturation than its gene-free equivalent through the elevation of provasculogenic genes (SDF-1α-7.4-fold, CXCR4-1.5-fold, eNOS-1.5-fold). Furthermore, we also found that the coculture on SDF-1α GAS secretes bioactive factors that significantly (p < 0.01) enhanced human Schwann cells' clustering to develop toward Bünger band-like structures. Conclusively, this study reports that SDF-1α GAS could be used to produce a bioactive vascularized construct through the enhancement of the cooperative effects between endothelial cells and ADSCs.

Secretome analysis of nerve repair mediating Schwann cells reveals Smad-dependent trophism

Schwann cells promote nerve regeneration by adaptation of a regenerative phenotype referred to as repair mediating Schwann cell. Down-regulation of myelin proteins, myelin clearance, formation of Bungner's bands, and secretion of trophic factors characterize this cell type. We have previously shown that the sphingosine-1-phosphate receptor agonist Fingolimod/FTY720P promotes the generation of this particular Schwann cell phenotype by activation of dedifferentiation markers and concomitant release of trophic factors resulting in enhanced neurite growth of dorsal root ganglion neurons. Despite its biomedical relevance, a detailed characterization of the corresponding Schwann cell secretome is lacking, and the impact of FTY720P on enhancing neurite growth is not defined. Here, we applied a label-free quantitative mass spectrometry approach to characterize the secretomes derived from primary neonatal and adult rat Schwann cells in response to FTY720P. We identified a large proportion of secreted proteins with a high overlap between the neonatal and adult Schwann cells, which can be associated with biologic processes such as development, axon growth, and regeneration. Moreover, FTY720P-treated Schwann cells release proteins downstream of Smad signaling known to support neurite growth. Our results therefore uncover a network of trophic factors involved in glial-mediated repair of the peripheral nervous system.-Schira, J., Heinen, A., Poschmann, G., Ziegler, B., Hartung, H.-P., Stühler, K., Küry, P. Secretome analysis of nerve repair mediating Schwann cells reveals Smad-dependent trophism.