The promotion of neural progenitor cells proliferation by aligned and randomly oriented collagen nanofibers through β1 integrin/MAPK signaling pathway

Abstract

In regenerative medicine, accumulating evidence demonstrates that the property of substrates monitors neural stem cells behavior. However, how stem cells sense and interpret biochemical and topographical cues remains elusive. This study aimed to explore the mechanism how nanofibrous scaffold modulated stem cells behavior. Spinal cord derived neural progenitor cells (NPCs) were cultured on electrospun aligned and randomly oriented collagen nanofibrous scaffolds. A 30% increase in proliferation and an elevation of BrdU incorporation were observed in NPCs on collagen nanofibers, compared to that on collagen-coated surface. In particular, NPCs expanded faster on aligned nanofibers in comparison with that on randomly oriented nanofibers. Moreover, an alteration in cell cycle progression with a reduced percentage of cells in G0/G1 phase and increased cell proliferation index (S phase plus G2/M phase) was also detected in NPCs cultured on collagen nanofibers. Incubating NPCs with anti-β1 integrin antibody or U1026 (an inhibitor of mitogen-activated protein kinase kinase, MEK) eliminated the altered cell cycle dynamics and BrdU incorporation induced by collagen nanofibers. In addition, cyclin D1 and cyclin dependent kinase 2 (CDK2), downstream genes of β1 integrin/mitogen-activated protein kinase (MAPK) pathway that control G1/S phase transition, were correspondingly regulated by nanofibers. Collectively, these data suggested that the property of substrate modulated NPCs proliferation by promoting cell cycle through β1 integrin/MAPK pathway. Our findings provide a better understanding of the interaction between NPCs and the substrate and therefore will pave way for regenerative medicine.