Self-assembling peptides with hBMP7 biological activity promote the differentiation of ADSCs into nucleus pulposus-like cells.

Functionalized self-assembling peptides, which display functional growth-factor bioactivity, can be designed by connecting the C-terminus of a pure self-assembling peptide with a short functional motif. In this study, we designed a novel functionalized peptide (RADA16-SNVI) in which an SNVI motif with hBMP-7 activity was conjugated onto the C-terminus of the RADA16 peptide via solid-phase synthesis. A mix of RADA16-SNVI and RADA16 solutions was used to create a functionalized peptide nanofiber scaffold (SNVI-RADA16). The hydrogels were analyzed by atomic force microscopy, circular dichroism, and scanning electron microscopy. The results showed that the SNVI-RADA16 solution effectively formed hydrogel. Next, we seeded the SNVI-RADA16 scaffold with adipose-derived stem cells (ADSCs) and investigated whether it displayed biological properties of nucleus pulposus tissue. SNVI-RADA16 displayed good biocompatibility with the ADSCs and induced their expression. Cells in SNVI-RADA16 gel had a greater secretion of the extracellular matrix marker collagen type II and aggrecan compared to ADSCs grown in monolayer and control gel (p < 0.05). The ratio of the aggrecan to collagen in cells in SNVI-RADA16 gel is approximately 29:1 after culture for 21 days. ADSCs in SNVI-RADA16 gels expressed the hypoxia-inducible factor 1α(HIF-1α) mRNA by real-time PCR. However, HIF-1 mRNA is absence in control gel and monolayer. The results suggested that the functionalized self-assembled peptide promotes the differentiation of ADSCs into nucleus pulposus-like cells. Thus, the designed SNVI-RADA16 self-assembling peptide hydrogel scaffolds may be suitable for application in nucleus pulposus tissue regeneration.