Phosphorylated proteins from food sources have been investigated as regulators of bone formation with potential benefits in treating osteoporosis. Egg, a cheap and nutritious food, is also the source of various proteins and bioactive peptides with applications in human health. Egg yolk is rich in phosvitin, the most phosphorylated protein in nature. Phosvitin has been shown to improve bone health in experimental animals, although the molecular mechanisms and its specific effects on bone-forming osteoblastic cells are incompletely understood. Previous work in our group has identified pancreatin-generated phosvitin phospho-peptides (PPP) as a potential source for bioactive peptides. Given this background, we examined the roles of both phosvitin and PPP in the function of osteoblastic cells. Our results demonstrated their potential to improve bone health by promoting osteoblast differentiation and proliferation, suppressing osteoclast recruitment and the deposition of extracellular matrix, although PPP appeared to demonstrate superior osteogenic functions compared to phosvitin alone.
Keywords: ECM; RANKL; osteoblast; phosphopeptides; phosphoprotein; phosvitin.