IL-17 enhances osteogenic differentiation of MSCs in 3D-printed PCL scaffold

Abstract

Objectives: Interleukin (IL)-17 has been found to play an essential role in bone remodeling, and we have proved that IL-17 regulates the osteogenesis of mesenchymal stem cells (MSCs) trough osteocyte-specific pathways. Polycaprolactone (PCL) is a biodegradable polyester material approved by the FDA for its use in implants, drug delivery devices and tissue engineering. This study aimed to employ a 3D-printed PCL scaffold exploited for bone tissue engineering and use Transwell assays with osteocytes co-culture to examine whether the PCL scaffold could further enhance osteogenic differentiation and mineralization. Methods: Mouse MSCs purified from mouse long bones were cultured on 3D-printed PCL discs. The scaffolds with mMSCs were placed at the bottom chamber of Transwell plates and MLO-Y4 osteocytes seeded in the upper chambers were placed over scaffolds in osteogenic media. After 10 d of culture in osteogenic media containing IL-17, Alizarin red staining was used to analyze the appearance of mineralized nodules. Furthermore, we repeated the assay with human induced pluripotent stem cell-derived MSCs which were previously obtained with a clinically compliant protocol and successfully used in regeneration. Results: Compared with the control, cultures grown on the 3D-printed PCL scaffold showed an obvious increase in mineralized nodule formation in both mouse and human MSCs as early as day 10. Additionally, IL-17 alone or co-culture with MLO-Y4 osteocytes enhanced osteogenesis in these cultures. Furthermore, the synergistically role of IL-17 and osteocytes could be found in the osteogenesis within the scaffold. Conclusions: The present study confirms that the 3D culture on PCL scaffold enhances IL-17–stimulated osteogenesis of MSCs when co-cultured with MLO-Y4 osteocytes. These synergistic effects by using PCL 3D-scaffolds support the potential benefits of IL-17–induced MSCs in the treatment of bone loss diseases and in the induction of self-renewal and self-repair of damaged osseous tissue through tissue engineering.