Sialoglycoprotein isolated from Carassius auratus eggs promotes osteoblast differentiation via targeting the p38 mitogen-activated protein kinase-dependent Wnt/β-catenin and BMP2/Smads pathways

In the current study, sialoglycoprotein isolated from eggs of Carassius auratus promoted MC3T3-E1 cells proliferation and differentiation, as assessed by MTT, mineralized nodule formation in vitro, as well as new osteoid formation in neonatal mouse calvarias ex vivo. Further research revealed that Ca-SGP facilitated osteogenesis via activating BMP2/Smads, Wnt/-catenin, and p38MAPK signaling pathways. What is more, p38MAPK inhibitor SB203580 down-regulated related mRNA and protein expression of BMP2/Smads and Wnt/-catenin signaling pathways, suggesting that p38MAPK pathway might be important for activation of BMP2/Smads and Wnt/-catenin pathways in Ca-SGP-induced osteoblastic differentiation. In conclusion, it was demonstrated that Ca-SGP promotes osteoblasts differentiation via activating p38MAPK-dependent BMP2/Smads and Wnt/-catenin signaling pathways, which may provide basis for the use of Ca-SGP as a potential agent to treat bone loss-associated diseases such as osteoporosis. Practical applicationCarassius auratus eggs are one of the major by-products during fish processing and contain sialoglycoprotein which plays an important role in biological functions. However, they have not been high-value utilized. This study demonstrated that Sialoglycoprotein isolated from eggs of C. auratus (Ca-SGP) promoted MC3T3-E1 cells proliferation, differentiation and mineralized nodule formation in vitro, as well as neonatal mouse calvarias formation ex vivo, which may provide basis for a novel application of C. auratus eggs as a functional food used to accelerate bone formation.