Lactoferrin Induces Osteoblast Growth through IGF-1R

Abstract EN

Objectives.

To investigate the role of the IGF-1R by which lactoferrin induces osteoblast growth.

Methods.

Osteoblast received 5 d lactoferrin intervention at a concentration of 0.1, 1, 10, 100, and 1000 μg/mL, and the IGF-1 and IGF-1R were detected using RT-PCR and western blot.

The osteoblast into the control, 100 μg/mL lactoferrin, Neo-scramble (NS, empty vector), NS + 100 μg/mL lactoferrin, shIGF-1R and shIGF-1R + 100 μg/mL lactoferrin group.

We test the apoptosis and proliferation and the level of PI3K and RAS in osteoblasts after 5 d intervention.

Results.

(1) 1, 10, 100, and 1000 μg/mL lactoferrin induced the expression of IGF-1 mRNA and protein.

10 μg/mL and 100 μg/mL lactoferrin induced the expression of IGF-1R mRNA and protein.

(2) Lactoferrin (100 μg/mL) induced osteoblast proliferation while inhibiting apoptosis.

Osteoblasts with silenced IGF-1R exhibited decreased proliferation but increased apoptosis.

MMT staining and flow cytometry both indicated that there was no significant difference between the shIGF-1R group and the shIGF-1R + 100 μg/mL lactoferrin group.

(3) Lactoferrin (100 μg/mL) induced PI3K and RAS phosphorylation and silence of IGF-1R resulted in decreased p-PI3K and p-RAS expression.

Lactoferrin-treated shIGF-1R cells showed significantly higher level of p-PI3K and p-RAS when compared with shIGF-1R.

Conclusion.

Lactoferrin induced IGF-1/IGF-1R in a concentration-dependent manner.

Lactoferrin promoted osteoblast proliferation while inhibiting apoptosis through IGF-1R.

Lactoferrin activated PI3K and RAS phosphorylation via an IGF-1R independent pathway.