Approaches to Optimizing Fibroblast Growth Factor 18 Protein Expression in Escherichia coli and its Osteogenic Activity

Background: The fibroblast growth factor (FGF) family is essential to tissue development and stem cell differentiation; therefore, there is increasing interest in the clinical application of FGFs, resulting in increasing demand for active recombinant human FGFs (rhFGFs). Objective: To improve the production of rhFGF18, we determined the optimal culture conditions required to maximize rhFGF18 protein expression E. coli. Method: Competent cell type, inducer concentration, induction temperature, and induction time for the optimal expression of rhFGF18 were analysed. Results: The rhFGF18 protein expression was highest in BL21 competent cells at an L-arabinose induction concentration of 0.1% (w/v), an induction temperature of 10 °C, and an induction time of 6 h under the control of an araBAD promoter introduced using the pBAD-HisA vector. Conclusion: Under optimal culture conditions, the rhFGF18 protein could induce osteogenic differentiation by increasing the alkaline phosphatase activity and mineralization activity. The approaches described herein may be useful for producing active rhFGF18 to meet the increasing demands for its pharmacological application, allowing for its future clinical use.