<p>Ultra-Small Lysozyme-Protected Gold Nanoclusters as Nanomedicines Inducing Osteogenic Differentiation</p>

Abstract

Ultra-small gold nanoclusters (AuNCs), as emerging fluorescent nanomaterials with excellent biocompatibility, have been widely investigated for in vivo biomedical applications. However, their effects in guiding osteogenic differentiation have not been investigated, which are important for osteoporosis therapy and bone regeneration. Herein, for the first time, lysozymeprotected AuNCs (Lys-AuNCs) are used to stimulate osteogenic differentiation, which have the potential for the treatment of bone disease. Methods: Proliferation of MC3T3E-1 is important for osteogenic differentiation. First, the proliferation rate of MC3T3E-1 was studied by Cell Counting Kit-8 (CCK8) assays. Signaling pathways of PI3K/Akt play central roles in controlling proliferation throughout the body. The expression of PI3K/Akt was investigated in the presence of lysozyme, and lysozyme-protected AuNCs (Lys-AuNCs) by Western blot (WB) and intracellular cell imaging to evacuate the osteogenic differentiation mechanisms. Moreover, the formation of osteoclasts (OC) plays a negative role in the differentiation of osteoblasts. Nuclear factor κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) signaling pathways are used to understand the negative influence of the osteogenic differentiation by the investigation of Raw 264.7 cell line. Raw 264.7 (murine macrophage-like) cells and NIH/3T3 (mouse fibroblast) cells were treated with tyloxapol, and the cell viability was assessed. Raw 264.7 cells have also been used for in vitro studies, on understanding the osteoclast formation and function. The induced osteoclasts were identified by TRAP confocal fluorescence imaging. These key factors in osteoclast formation, such as (NFATc-1, c-Fos, V-ATPase-2 and CTSK), were investigated by Western blot. Results: Based on the above investigation, Lys-AuNCs were found to promote osteogenic differentiation and decrease osteoclast activity. It is noteworthy that the lysozyme (protected template), AuNPs, or the mixture of Lysozyme and AuNPs have negligible effects on osteoblastic differentiation compared to Lys-AuNCs. Conclusion: This study opens up a novel avenue to develop a new gold nanomaterial for promoting osteogenic differentiation. The possibility of using AuNCs as nanomedicines for the treatment of osteoporosis can be expected.

Effects of Gold Nanoparticles Combined Human β-defensin 3 on The Alveolar Bone of Experimental Periodontitis

“…In our study, the administration of AuNPs combined hBD3 increased the expression of ALP, while decreased TRAP expression. Similar effects were observed in MG-63 cells and MC3T3E-1 treated by human beta-defensins and gold nanoclusters respectively [22,23].…”

Effects of gold nanoparticles combined with human β-defensin 3 on the alveolar bone loss of periodontitis in rat

“…In our study, the administration of AuNPs combined with hBD3 increased the expression of ALP while decreasing TRAP expression. Similar effects were observed in MG-63 cells and MC3T3E-1 cells treated with human beta-defensins and gold nanoclusters, respectively [ 29 , 30 ].…”

Effects of lactoferrin on osteogenic differentiation and related gene expressions of osteoblast precursor cells MC3T3-E1 under mechanical strain

“…ALP is a sign of early osteoblast differentiation, and OCN represents osteoblast maturation. COL-1 is one of the main components that constitute the extracellular matrix of bone tissues, indicating that early strain stimulation can promote the synthesis of extracellular matrix of bone tissues, and it is the material basis of bone tissue remod-eling under strain (18). IL-6, as a multifunctional cytokine, participates in the periodontal tissue remodeling during orthodontic tooth movement and acts as an effective osteoclast activating factor to stimulate osteoclast production and bone resorption activities.…”