Xu Fangfang, Wang Kevin Yueju, Wang Nan, Li Gangqiang, Liu Dehu
Institute of Biotechnology Research, Chinese Academy of Agricultural Sciences, Beijing, China.
Natural Sciences Department, Northeastern State University. Broken Arrow, OK, United States of America.
PLoS One. 2017 Jul 27;12(7):e0181939. doi: 10.1371/journal.pone.0181939. eCollection 2017.
Glucagon-like peptide 1 (GLP-1) is a very potent insulinotropic hormone secreted into the blood stream after eating. Thus, it has potential to be used in therapeutic treatment of diabetes. The half-life of GLP-1, however, is very short due to its rapid cleavage by dipeptidyl peptidase IV (DPP-IV). This presents a great challenge if it is to be used as a therapeutic drug. GLP-1, like many other small peptides, is commonly produced through chemical synthesis, but is limited by cost and product quantity. In order to overcome these problems, a sequence encoding a six codon-optimized tandem repeats of modified GLP-1 was constructed and expressed in the E. coli to produce a protease-resistant protein, 6×mGLP-1. The purified recombinant 6×mGLP-1, with a yield of approximately 20 mg/L, could be digested with trypsin to obtain single peptides. The single mGLP-1 peptides significantly stimulated the proliferation of a mouse pancreatic β cell line, MIN6. The recombinant peptide also greatly improved the oral glucose tolerance test of mice, exerted a positive glucoregulatory effect, and most notably had a glucose lowering effect for as long as 16.7 hours in mice altered to create a type 2 diabetic condition and exerted a positive glucoregulatory effect in db/db mice. These results indicate that recombinant 6×mGLP-1 has great potential to be used as an effective and cost-efficient drug for the treatment of type 2 diabetes.
胰高血糖素样肽1（GLP-1）是一种在进食后分泌到血流中的强效促胰岛素分泌激素。因此，它有潜力用于糖尿病的治疗。然而，由于GLP-1会被二肽基肽酶IV（DPP-IV）快速裂解，其半衰期非常短。如果要将其用作治疗药物，这将是一个巨大的挑战。与许多其他小肽一样，GLP-1通常通过化学合成产生，但受到成本和产品数量的限制。为了克服这些问题，构建了一个编码经过六个密码子优化的修饰GLP-1串联重复序列，并在大肠杆菌中表达以产生一种抗蛋白酶的蛋白质，即6×mGLP-1。纯化后的重组6×mGLP-1产量约为20 mg/L，可用胰蛋白酶消化以获得单个肽段。单个mGLP-1肽段显著刺激了小鼠胰腺β细胞系MIN6的增殖。该重组肽还极大地改善了小鼠的口服葡萄糖耐量试验，发挥了积极的血糖调节作用，最值得注意的是，在诱导形成2型糖尿病状态的小鼠中，其降血糖作用长达16.7小时，并在db/db小鼠中发挥了积极的血糖调节作用。这些结果表明，重组6×mGLP-1有很大潜力用作治疗2型糖尿病的有效且经济高效的药物。
