Developing GLP-1 Conjugated Self-Assembling Nanofibers Using Copper-Catalyzed Alkyne-Azide Cycloaddition and Evaluation of Their Biological Activity

Bioconjug Chem. 2021 Apr 21;32(4):810-820. doi: 10.1021/acs.bioconjchem.1c00091. Epub 2021 Apr 12.

Abstract

Glucagon-like peptide-1 GLP-1 is a gut-derived peptide secreted from pancreatic β-cells that reduces blood glucose levels and body weight; however, native GLP-1 (GLP-1(7-36)-NH2 and GLP-1(7-37)) have short in vivo circulation half-lives (∼2 min) due to proteolytic degradation and rapid renal clearance due to its low molecular weight (MW; 3297.7 Da). This study aimed to improve the proteolytic stability and delivery properties of glucagon-like peptide-1 (GLP-1) through modifications that form nanostructures. For this purpose, N- (NtG) and C-terminal (CtG), and Lys26 side chain (K26G) alkyne-modified GLP-1 analogues were conjugated to an azide-modified lipidic peptide (L) to give N-L, C-L, and K-26-L, respectively; or CtG was conjugated with a fibrilizing self-assembling peptide (SAP) (AEAEAKAK)3 to yield C-S, using copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). N-L demonstrated the best serum stability (t1/2 > 48 h) compared to K-26-L (44 h), C-L (20 h), C-S (27 h), and the parental GLP-1(7-36;A8G)-NH2 (A8G) (19 h) peptides. Each conjugate demonstrated subnanomolar hGLP-1RA potency, and none demonstrated toxicity toward PC-3 cells at concentrations up to 1 μM. Each analogue was observed by transmission electron microscopy to form fibrils in solution. K-26-L demonstrated among the best human serum stability (t1/2 = 44 h) and similar hGLP-1RA potency (EC50 48 pM) to C-S. In conclusion, this study provided an alternative to lipid modification, i.e., fibrillizing peptides, that could improve pharmacokinetic parameters of GLP-1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkynes / chemistry*
  • Amino Acid Sequence
  • Animals
  • Azides / chemistry*
  • Catalysis
  • Cell Line
  • Cell Survival / drug effects
  • Copper / chemistry*
  • Cycloaddition Reaction
  • Glucagon-Like Peptide 1 / chemistry*
  • Glucagon-Like Peptide 1 / pharmacology
  • Glucagon-Like Peptide-1 Receptor / agonists
  • Humans
  • Microscopy, Electron, Transmission
  • Nanofibers / chemistry*

Substances

  • Alkynes
  • Azides
  • GLP1R protein, human
  • Glucagon-Like Peptide-1 Receptor
  • Copper
  • Glucagon-Like Peptide 1