Expression and purification of FGF21 in Pichia pastoris and its effect on fibroblast-cell migration

Fibroblast growth factor (FGF) 21 functions in the maintenance of glucose homeostasis and exerts protective effects on the liver, heat and kidneys. However, the roles of FGF21 in other tissue types are yet to be fully elucidated. The present study detected elevated expression levels of FGF21 in skin tissue. Furthermore, it was revealed that FGF21 expression in the skin was induced upon wounding. In addition, beta-klotho expression was detected in the skin tissue. To examine the role of FGF21 in the wound healing process, recombinant human (h) FGF21 was expressed in a the yeast strain Pichia (P.) pastoris, a well-known system for recombinant protein production. Based on the sequence of hFGF21 and the optimal codon of P. pastoris, codon-optimized FGF21 open reading frame sequences were obtained using seven pairs of 55-59-nt primers with seven rounds of PCR. The recombinant FGF21 was purified and its function was examined in human fibroblast cells using a wound healing cell migration assay. Treatment with FGF21 promoted cell migration, which is an important step in wound healing. Furthermore, FGF21 treatment enhanced the activity of c-Jun N-terminal kinase, a key regulator in fibroblast-cell migration. In conclusion, FGF21 is induced after wounding and FGF21 expressed and purified from yeast markedly accelerates wound healing. The present study was the first to elucidate the function of FGF21 in skin tissues and provided a theoretical basis for the use of FGF21 in the treatment of skin wounds.