Addition of a cysteine to glucagon-like peptide-1 (GLP-1) conjugates GLP-1 to albumin in serum and prolongs GLP-1 action in vivo.
Glucagon-like peptide-1 (GLP-1) is a promising new therapeutic agent for the treatment of type 2 diabetes. However, GLP-1 has a short half-life (t(1/)(2)<2min) due to rapid degradation by dipeptidyl peptidase IV in vivo. To circumvent this problem, a recombinant mGLP-1 with a cysteine at the C-terminus of GLP-1 was expressed in Escherichia coli and purified by affinity and reverse-phase chromatography. This addition of a cysteine facilitates mGLP-1 binding to serum albumin both in vitro and in vivo, thus protecting mGLP-1 from protease degradation. Similar to GLP-1, mGLP-1 stimulated cAMP production in PC12 cells and exhibited insulinotropic activity in MIN6 cells under in vitro culture conditions. Importantly, in glucose tolerance tests mice treated with mGLP-1 exhibited much lower glucose levels and much higher insulin levels versus that in mice treated with unmodified GLP-1. Furthermore, the effects of mGLP-1 on reduction of blood glucose levels lasted for 6-7h, while the effects of unmodified GLP-1 only lasted for 0.5-1h after injection. These results demonstrate that mGLP-1 is biologically active and its pharmaceutical efficacy is largely enhanced by the cysteine-mediated covalent conjugation with albumin in the serum after injection. Therefore, the mGLP-1 with a cysteine may be a better potential therapeutic drug than the unmodified GLP-1 for treating type 2 diabetes.
Wu
Ye-Lin
YL
School of Life Science, East China Normal University, 3663 Zhongshan North Road, Shanghai, 200062, PR China.
Huang
Jing
J
Xu
Jin
J
Liu
Jian
J
Feng
Zhen
Z
Wang
Yang
Y
Lai
Yuping
Y
Wu
Zi-Rong
ZR
D000818:Animals; D002460:Cell Line; D003545:Cysteine / Q000737:chemistry / Q000235:genetics*; D052216:Glucagon-Like Peptide 1 / Q000235:genetics / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D051379:Mice; D016501:Neurites / Q000378:metabolism; D016716:PC12 Cells; D011485:Protein Binding / Q000235:genetics / Q000502:physiology; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D012709:Serum Albumin / Q000378:metabolism*
D007328:Insulin; D011994:Recombinant Proteins; D012709:Serum Albumin; D052216:Glucagon-Like Peptide 1; D003545:Cysteine