Construction and expression of releasable glucagon-like peptide-1 and human serum albumin fusion proteins and preliminary evaluation of their pharmacodynamics and pharmacokinetics / 军事医学

ABSTRACT

Objective To construct four types of glucagon-like peptide-1 (GLP-1) and human serum albumin (HSA) fusion proteins that can be realeased at different rate in vivo by introducing protease cleavage sites between these two moieties.The therapeutic effect and release rate are studied to achieve balanced pharmacokinetics ( PK) and pharmacody-namics ( PD) of GLP-1 and HSA fusion proteins.Methods The gene with different polypeptide joint of GLP-1 and HSA fusion proteins were synthesized by overlap extension PCR amplification, cloned into expression vector pPIC9 and transformed into Pichia pastoris GS115.Then, fusion proteins were obtained by protein purification after being induced by methanol.The preliminary PK and PD of the fusion proteins were studied after purification.Results The fusion protein Gly2-GLP-1-GGGGG-HSA showed no release while Gly2-GLP-1-VTR-HSA, Gly2-GLP-1-SARSVRA-HSA, and Gly2-GLP-1-GRSRVTRSV-HSA showed a slow, medium and fast release rate, respectively, after incubation with furin.In vitro biological activity test results dispalyed that each type of fusion protein promoted insulin secretion of MIN6 cells.In vivo PK test indicated the half-life size of fusion proteins was the largest in Gly2-GLP-1-GGGGG-HSA, followed by Gly2-GLP-1-VTR-HSA, Gly2-GLP-1-SARSVRA-HSA, and Gly2-GLP-1-GRSRVTRSV-HSA.In vivo PD test exhibited hypoglycemic activity that was the highest in Gly2-GLP-1-VTR-HSA, followed by Gly2-GLP-1-SARSVRA-HSA, Gly2-GLP-1-GRSRVTRSV-HSA, and Gly2-GLP-1-GGGGG-HSA.Conclusion GLP-1 can be released from fusion proteins with full activity after the introduction of protease cleavage sites.Releasable fusion proteins at an appropriate release rate have the most balanced PK and PD.