Zero-order controlled release of BMP2-derived peptide P24 from the chitosan scaffold by chemical grafting modification technique for promotion of osteogenesis in vitro and enhancement of bone repair in vivo

Abstract

Combination of tissue-engineered bone scaffolds with cell-adhesive, osteoconductive, or osteoinductive biomolecules is a critical strategy to improve their properties that significantly influence cellular behaviors, such as adhesion, proliferation, and differentiation, which is beneficial for critical-sized bone defects repairing. However, the traditional surface modification techniques, such as physical adsorption, coating, and plasma treatment, et al, have great limitations for immobilization of bioactive molecules due to undesirable controlled delivery performance or overly complex multistep procedures. In this study, we functionalized the chitosan/hydroxyapatite (CS/HA) biomimetic composite scaffold for controlled delivery of BMP2-derived peptide (P24) by the chemical grafting modification technique: firstly, P24 was conjugated with a thiolated chitosan, chitosan-4-thiobutylamidine (CS-TBA); secondly, the resultant CS-P24 was then combined with HA to prepare CS-P24/HA scaffolds. The effect of CS-P24/HA scaffolds on bone regeneration was evaluated, along with the underlying biological mechanisms responsible in vitro and in vivo. In vitro, the controlled and sustained release of bioactive P24 could last up to 90 days, furthermore, the release profiles of CS-5%P24/HA and CS-10%P24/HA were linear and could be fitted according to zero-order kinetic model (R2=0.9929; R2=0.9757); P24 on the scaffold significantly promoted cell adhesion, proliferation, osteodifferentiation, and mineralization with synergistic effects. Bone marrow stromal cells (BMSCs) revealed spindle-shaped surface morphology, indicating the CS-P24/HA scaffolds supported cell adhesion and possessed a high proliferation rate that varied according to the P24 concentration levels. Furthermore, mRNA levels for OCN, Runx2, and collagen I were significantly up-regulated on CS-P24/HA scaffolds compared with cells grown on CS/HA scaffolds in vitro (p < 0.05). Similarly, the BMSCs exhibited a higher ALP expression and calcium deposition level on CS-P24/HA scaffolds compared with CS/HA scaffolds (p < 0.05). In vivo, osteoinductive studies revealed a significantly higher ectopic osteogenesis level of CS-10%P24/HA scaffolds in rat dorsal muscle pockets compared with that of CS/HA scaffolds. Finally, CS-P24/HA scaffolds showed superior performance in the reconstruction of rat calvarial bone defects. This novel CS-P24/HA scaffold is deemed a strong potential candidate for the repair of bone defects in human bone tissue engineering.

Bergenin Activates SIRT1 as a Novel Therapeutic Agent for Osteogenesis of Bone Mesenchymal Stem Cells

“…To conduct effective statistical analysis, sample size ≥ 4/group is required. In this study, n = 6/group was set, which was consistent with our previous study (Chen et al, 2017) and other published studies (Chen et al, 2017; Deng et al, 2018; Wang et al, 2018). As reported in previous studies (Gao et al, 2015; Yun et al, 2015; Wang et al, 2017), the Bergenin group was intraperitoneally treated with Bergenin in phosphate-buffered saline (PBS) at 50 mg/kg body weight weekly after surgery, throughout the 8 weeks; the sham group was treated with an equal volume of PBS.…”

Bioactive Scaffolds for Regeneration of Cartilage and Subchondral Bone Interface

“…Although many BMSCs-specific-affinity peptides and signaling molecules have been incorporated into scaffolds to promote osteochondral defect reconstruction, these strategies often induce various side effects. For instance, some peptides can specifically recognize and recruit pluripotent stem cells as well as promote osteogenesis in subchondral bone, which has the potential to increase cartilage calcification 15 , 56 , 57 . Some molecules which could preserve cartilage from degradation, such as TGF-β signaling trigger molecules, may trigger osteoarthritis via perturbing subchondral bone homeostasis 58 - 60 .…”

BMP2‐mimicking peptide modified with E7 coupling to calcined bovine bone enhanced bone regeneration associating with activation of the Runx2/SP7 signaling axis

“…It has been proved that long-term delivery of BMP2 enhances orthotopic bone formation more than short-term distribution. 26,27 In response to the issue of delivery of the BMP2-mimicking peptide, many novel immobilization strategies have emerged, such as the use of a chitosan scaffold, 28 layer-by-layer technology, non-viral delivery of plasmid DNA coding, 29 and electrodeposition. However, these strategies are not desirable for multistep procedures that are time-consuming and may lead to inconsistent results with undesirable delivery performance.…”