Hen egg yolk phosvitin stimulates osteoblast differentiation in the absence of ascorbic acid

Promoting effect of phosvitin in the mineralization of eggshell inner membrane with the application in osteogenic induction scaffold

Exploring affordable and easily prepared inorganic-organic hybrid membrane materials has attracted a great interest in the bone repair field. This study is based on biomimetic mineralization technique to study the role of phosvitin (PV) in the mineralized process of eggshell inner membrane. Results showed that PV promoted the formation of hydroxyapatite on the eggshell inner membrane surface, and the phosvitin content in the simulated body fluid was decreased during the mineralization process. Besides, in vitro preosteoblast experiments indicated that mineralized membrane with PV exhibited more conducive to cell proliferation and differentiation than that mineralized membrane without PV. Interestingly, with the increase of mineralization time, the stimulating ability of mineralized membranes with PV on adhesion, proliferation, alkaline phosphatase activity and collagen type I content gradually improved. In summary, the eggshell inner membrane composites mineralized with PV obtained by biomimetic mineralization might be potential scaffold materials for bone repair.

Effect of the phosphorylation structure in casein phosphopeptides on the proliferation, differentiation, and mineralization of osteoblasts and its mechanism

Our previous studies have shown that highly phosphorylated casein phosphopeptides (residues 1-25) P5 could efficiently bind calcium and promote intestinal calcium absorption, and enhanced bone development in rats. The purpose of this study was to investigate the effect of the phosphorylation structure in P5 on the proliferation, differentiation, and mineralization of osteoblasts (MC3T3-E1) and its mechanism. P5 was obtained by high-performance liquid chromatography (HPLC) and non-phosphorylated peptide P5-0 was obtained by chemical synthesis. Compared with the control group, the proliferation rate of MC3T3-E1 cells treated by P5 was 1.10 times that of P5-0 at 200 μg mL-1. P5 caused the cell cycle retention of MC3T3-E1 cells in the G2/M phase, while P5-0 had no significant difference in the G2/M phase. MC3T3-E1 cells incubated with P5 showed stronger alkaline phosphatase (ALP) activity than with P5-0, suggesting a tendency to promote cellular differentiation. Compared to the P5-0 treatment group, the P5 treatment group at concentrations of 10 μg mL-1 showed significant differences in the mineralization rates (p < 0.05). P5 significantly upregulated the expressions of Runx2, ALP, ColIα1, and OCN compared with the control group (p < 0.05). In addition, in silico molecular docking showed that the binding force of the P5-EGFR complex was stronger than that of the P5-0-EGFR complex, which was significantly related to the phosphorylation structure in P5 and might be an important reason for osteoblast proliferation. In conclusion, the phosphorylation structure and amino acid composition in P5 stimulated the osteogenic activity of MC3T3-E1 cells, and could be expected to be a functional food for the prevention of osteoporosis.

Novel extraction technologies and potential applications of egg yolk proteins

The high nutritional value and diverse functional properties of egg yolk proteins have led to its widespread use in the fields of food, medicine, and cosmetics. Various extraction methods have been reported to obtain the proteins from egg yolk, however, their utilization is limited due to the relatively low extraction efficiency and/or toxic solvents involved. Several simpler and greener technologies, especially physical fields (ultrasound), have been successfully developed to improve the extraction efficiency. The egg yolk proteins may exert multiple biological activities, enabling them to be a promising tool in improve human health and wellbeing, such as anti-obesity, anti-atherosclerosis, anti-osteoporosis, diagnosis and therapy for SARS-CoV-2 infections. This article summarizes the novel extraction technologies and latest applications of the egg yolk proteins in the recent 5 years, which should stimulate their utilization as health-promoting functional ingredients in foods and other commercial products.

Recent Advances in Applications of Bioactive Egg Compounds in Nonfood Sectors

Egg, a highly nutritious food, contains high-quality proteins, vitamins, and minerals. This food has been reported for its potential pharmacological properties, including antibacterial, anti-cancer, anti-inflammatory, angiotensin-converting enzyme (ACE) inhibition, immunomodulatory effects, and use in tissue engineering applications. The significance of eggs and their components in disease prevention and treatment is worth more attention. Eggs not only have been known as a "functional food" to combat diseases and facilitate the promotion of optimal health, but also have numerous industrial applications. The current review focuses on different perceptions and non-food applications of eggs, including cosmetics. The versatility of eggs from an industrial perspective makes them a potential candidate for further exploration of several novel components.

Avian Egg: A Multifaceted Biomaterial for Tissue Engineering

Most components in avian eggs, offering a natural and environmentally friendly source of raw materials, hold great potential in tissue engineering. An avian egg consists of several beneficial elements: the protective eggshell, the eggshell membrane, the egg white (albumen), and the egg yolk (vitellus). The eggshell is mostly composed of calcium carbonate and has intrinsic biological properties that stimulate bone repair. It is a suitable precursor for the synthesis of hydroxyapatite and calcium phosphate, which are particularly relevant for bone tissue engineering. The eggshell membrane is a thin protein-based layer with a fibrous structure and is constituted of several valuable biopolymers, such as collagen and hyaluronic acid, that are also found in the human extracellular matrix. As a result, the eggshell membrane has found several applications in skin tissue repair and regeneration. The egg white is a protein-rich material that is under investigation for the design of functional protein-based hydrogel scaffolds. The egg yolk, mostly composed of lipids but also diverse essential nutrients (e.g., proteins, minerals, vitamins), has potential applications in wound healing and bone tissue engineering. This review summarizes the advantages and status of each egg component in tissue engineering and regenerative medicine, but also covers their current limitations and future perspectives.

Phosvitin Derived Phospho-Peptides Show Better Osteogenic Potential than Intact Phosvitin in MC3T3-E1 Osteoblastic Cells

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.

Bioactive Minor Egg Components

In the last 15 years, the development of functional genomics has increased the number of egg proteins identified from 50 to about 1300. These proteins are initially present in eggs to support a harmonious embryonic development. Consequently, this closed embryonic chamber contains molecules exhibiting diverse functions, including defense, nutrition and many predicted biological activities, which have been investigated using both bioinformatics and experimental investigations. In this chapter, we focus on some very interesting activities of high potential reported for minor egg proteins (excluding ovalbumin, ovotransferrin and lysozyme). The shell matrix proteins are involved in the calcification process to define and control the final texture of the shell and thereby its mechanical properties. Antimicrobial proteins are part of innate immunity and are mainly present in the white and vitelline membranes. They encompass several protein families, including protease inhibitors, vitamin-binding proteins, defensins, LBP-PLUNC family proteins and heparin-binding proteins. The egg also possesses additional bioactive proteins with direct anti-cancerous and antioxidant activities or whose biochemical properties are currently used to develop diagnostic tools and strategies for targeted therapy. Finally, this chapter also reports some emerging functions in tissue remodeling/wound healing and proposes some relevant bioactive candidates and research fields that would be interesting to investigate further.

How Can the Value and Use of Egg Yolk Be Increased?

The major driving force for the egg consumption in the United States over the past few decades was processed egg. However, the consumption of egg through the processed egg reached the plateau in recent years because of the imbalance in the demands between the egg white and yolk products. The consumer demands for egg white products are very high while those for the egg yolk, the co-product of dried egg white, are low because of the negative perceptions on egg yolk. Two key approaches that can be used to increase the value and use of egg yolk are: (1) developing new commodity products by fractionating egg yolk and apply them in various food processing, and (2) separating functional proteins and lipids from yolk and use them as is or further develop functional peptides and functional lipids and use them as pharmaceutical, nutraceutical, and cosmeceutical agents. These approaches can diversify the use of egg yolk, which eventually will help increase the consumption of egg. This review (1) discusses the current use of egg yolk products and the development of new functional commodity products from egg yolk, (2) review the important functional components in egg yolk and overview the current separation methods and their applications, (3) discuss the production of functional peptides and lipids using the separated egg proteins and lipids, and (4) suggest the future directions for the best use of egg yolk components. Development of scale-up production methods, which is vital for the practical applications, is discussed when appropriate.

Phosphorylated serine clusters of phosvitin plays a crucial role in the regulatory mineralization

Phosphorylation of phosvitin has been proved to play an important role in the mineralization, but the active region of phosvitin is still not known yet. Four phosvitin phosphopeptides (PPPs) were obtained after separating from ion exchange column and desalting from gel filtration, and named as PPP0, PPP1, PPP3 and PPP4, respectively. The effect of PPP on the mineralization was investigated by pH-stat system, Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscope. SDS-PAGE and circular dichroism were applied to study the composition and the structure of PPP. Results showed that the order of promoting mineralization was as follows: PPP3 > phosvitin > PPP4 > PPP1 > control > PPP0. PPP0 and PPP1 was not involved in the mineralization, while the structure of PPP4 was too compact to promote mineralization because of its high β-sheet conformation. PPP3, which contained a 10 kDa peptide, is the most effective promoter for mineralization. LTQ-MS/MS results indicated that the phosphorylated serine clusters of phosvitin was the active region for promoting mineralization.

Effects of multiple freeze–thaw treatments on physicochemical and biological activities of egg phosvitin and its phosphopeptides

Multiple freeze–thaw treatments improved the emulsifying and biological activities of egg phosvitin.