Synthesis and Evaluation of a Series of Long‐Acting Glucagon‐Like Peptide‐1 (GLP‐1) Pentasaccharide Conjugates for the Treatment of Type 2 Diabetes

Abstract

The present study details the development of a family of novel D-Ala(8) glucagon-like peptide-1 (GLP-1) peptide conjugates by site specific conjugation to an antithrombin III (ATIII) binding carrier pentasaccharide through tetraethylene glycol linkers. All conjugates were found to possess potent insulin-releasing activity. Peptides with short linkers (<25 atoms) conjugated at Lys(34) and Lys(37) displayed strong GLP-1 receptor (GLP-1-R) binding affinity. All D-Ala(8) GLP-1 conjugates exhibited prominent glucose-lowering action. Biological activity of the Lys(37) short-linker peptide was evident up to 72 h post-injection. In agreement, the pharmacokinetic profile of this conjugate (t1/2 , 11 h) was superior to that of the GLP-1-R agonist, exenatide. Once-daily injection of the Lys(37) short-linker peptide in ob/ob mice for 21 days significantly decreased food intake and improved HbA1c and glucose tolerance. Islet size was decreased, with no discernible change in islet number. The beneficial effects of the Lys(37) short-linker peptide were similar to or better than either exenatide or liraglutide, another GLP-1-R agonist. In conclusion, GLP-1 peptides conjugated to an ATIII binding carrier pentasaccharide have a substantially prolonged bioactive profile compatible for possible once-weekly treatment of type 2 diabetes in humans.

Beneficial long‐term antidiabetic actions of N‐ and C‐terminally modified analogues of apelin‐13 in diet‐induced obese diabetic mice

“…Twice-daily administration of (pGlu)apelin-13 amide or exendin-4 produced distinct reductions in non-fasting glucose levels, accompanied by hyperinsulinaemia, elevated circulating GLP-1 levels, increased pancreatic insulin stores and enhanced glucose-induced insulin secretion. Such effects are well established for GLP-1 mimetics 30,31 and are also consistent with our previous data showing positive actions of apelin-13 on insulin secretion, cellular glucose uptake and as a modulator of incretins. 16 Administration of apelin-13 amide also induced a range of beneficial actions in DIO mice but the effects were generally inferior to those observed with additional Nterminal pyroglutamate modification, which seemed to confer greater stability and bioactivity in vitro.…”

“…Effects of twice daily i.p. administration of saline, exendin‐4, apelin‐13amide or (pGlu)apelin‐13amide (each at 25 nmol/kg bw) on A, α‐amylase activity; B, plasma GLP‐1; C, pancreatic insulin content; D, body weight (at end of study); E, fat mass (%), and F, bone mineral content measured by DXA scanner. Observations were made after 40 days of treatment of high‐fat‐fed (HF) and lean control mice.…”

Chemical Glycosylation and Its Application to Glucose Homeostasis-Regulating Peptides

“…Interestingly, insulin and GLP-1 were each modified by a novel CarboCarrier R technology bearing a sulfated pentasaccharide (De Kort et al, 2008;Irwin et al, 2015). The pentasaccharide specifically binds to plasma protein antithrombin III (ATIII) thereby increasing the plasma half-life of the conjugated protein at sub-anticoagulant concentrations.…”

“…They further studied the pharmacokinetic and pharmacodynamic properties of CarboCarrier R insulin analog modified at LysB29 (SCH 900948) in humans (Miltenburg et al, 2013) and their phase 1 studies confirmed an extended half-life when compared to endogenous insulin. The CarboCarrier R technology was also applied to a D-Ala 8 GLP-1 analog to produce 17 novel long-acting GLP-1 conjugates (Irwin et al, 2015). GLP-1 was modified at three positions by varying the length and chemical nature of the linker.…”

Exendin‐4(Lys27PAL)/gastrin/xenin‐8‐Gln: A novel acylated GLP‐1/gastrin/xenin hybrid peptide that improves metabolic status in obese‐diabetic (ob/ob) mice

“…20 Indeed, this is exemplified by liraglutide, the clinically approved T2DM drug that has a C-16 fatty acid molecule attached to Lys 26 , enabling noncovalent self-association with albumin. 20,21 For liraglutide, acylation does result in slightly lower intrinsic in vivo bioactivity, 22 but this is more than compensated for by a significant extension to the circulating half-life. 23 In accord with this, acylation has been employed to generate many longacting peptide analogues, including but not limited to, apelin, 24 insulin, 25 glucose-dependent insulinotropic polypeptide (GIP), [26][27][28][29] and xenin.…”