Genetically Engineered Epidermal Growth Factor Conjugate Crosses Cell Membrane

Expression, purification and functional identification of the modified hEGF protein

Human epidermal growth factor (hEGF) plays an important role in the growth and division of epithelial cells and has good application prospects in skin-related injuries and diseases. Weak skin penetration and rapid clearance of hEGF in skin via the mononuclear phagocyte system have restricted the application of hEGF. To overcome these shortcomings, the recombinant gene TAT-hEGF-CD47 was constructed in our experiments, and the fusion protein TAT-hEGF-CD47 was expressed, purified and renatured. The cell proliferation-promoting function, skin penetration and concentration of TAT-hEGF-CD47 in skin after its application were determined. The results showed that TAT-hEGF-CD47 effectively promoted human skin fibroblast and skin epithelial cell proliferation, and the proliferation-promoting effect was positively correlated with the TAT-hEGF-CD47 concentration. After administration to the skin, TAT-hEGF-CD47 effectively penetrated the epidermal layer of the skin because of the TAT domain and stayed in the skin for a long time because the CD47 fragment slowed its clearance via the mononuclear phagocytic system. In conclusion, TAT-hEGF-CD47 exhibits high cell proliferation-promoting activity, high skin penetration efficiency and long retention time in skin and has laid the foundation for its wide application in skin repair, ulcer, diabetes and even cancer treatments.

Increased synthesis of hyaluronic acid by enhanced penetration of CTP-EGF recombinant in human keratinocytes

BACKGROUND

Epidermal growth factor (EGF) plays an important role in regeneration and proliferation of skin cells. It synthesizes fibrous proteins, such as collagen, and induces the proliferation of keratinocytes and fibroblasts. It can also induce hyaluronic acid synthesis, which subsequently leads to improved skin elasticity, wrinkle improvement, and moisturizing effects. Thus, the EGF is an attractive cosmetic additive for skin care.

OBJECTIVES

We tested the use of cytoplasmic transduction peptide (CTP) as a delivery peptide for EGF into skin cells. Additionally, we characterized the skin permeability of CTP-EGF for its potential use in skin antiaging and antiwrinkle cosmetics.

METHODS

Skin penetration by recombinant CTP-EGF protein was confirmed using fluorescent imaging techniques. The ability to synthesize hyaluronic acid was confirmed by immunoblotting and ELISA.

RESULTS

CTP-EGF displayed cell membrane permeability and could penetrate skin cells. Treatment with CTP-EGF increased collagen protein formation, which is a major regulator of skin elasticity. Further, CTP-EGF treatment led to increased expression of HAS3 enzyme and subsequently boosted hyaluronic acid synthesis. The CTP-EGF also performed better than natural EGF in wound healing assays.

CONCLUSIONS

CTP-EGF has a superior ability, compared with natural EGF, to permeate skin and induce hyaluronic acid synthesis and collagen formation. Thus, it has great potential to be used in cosmetics and therapeutic agents to improve wrinkles and health of the skin.

PEP-1-PON1 protein regulates inflammatory response in raw 264.7 macrophages and ameliorates inflammation in a TPA-induced animal model

Paraoxonase 1 (PON1) is an antioxidant enzyme which plays a central role in various diseases. However, the mechanism and function of PON1 protein in inflammation are poorly understood. Since PON1 protein alone cannot be delivered into cells, we generated a cell permeable PEP-1-PON1 protein using protein transduction domains, and examined whether it can protect against cell death in lipopolysaccharide (LPS) or hydrogen peroxide (H₂O₂)-treated Raw 264.7 cells as well as mice with 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced skin inflammation. We demonstrated that PEP-1-PON1 protein transduced into Raw 264.7 cells and markedly protected against LPS or H₂O₂-induced cell death by inhibiting cellular reactive oxygen species (ROS) levels, the inflammatory mediator’s expression, activation of mitogen-activated protein kinases (MAPKs) and cellular apoptosis. Furthermore, topically applied PEP-1-PON1 protein ameliorates TPA-treated mice skin inflammation via a reduction of inflammatory response. Our results indicate that PEP-1-PON1 protein plays a key role in inflammation and oxidative stress in vitro and in vivo. Therefore, we suggest that PEP-1-PON1 protein may provide a potential protein therapy against oxidative stress and inflammation.