The physical stability of peptide-based drugs is of great interest to the pharmaceutical industry. Glucagon-like peptide 1 (GLP-1) is a 31-amino acid peptide hormone, the analogs of which are frequently used in the treatment of type 2 diabetes. We investigated the physical stability of GLP-1 and its C-terminal amide derivative, GLP-1-Am, both of which aggregate into amyloid fibrils. While off-pathway oligomers have been proposed to explain the unusual aggregation kinetics observed previously for GLP-1 under specific conditions, these oligomers have not been studied in any detail. Such states are important as they may represent potential sources of cytotoxicity and immunogenicity. Here, we identified and isolated stable, low-molecular-weight oligomers of GLP-1 and GLP-1-Am, using size-exclusion chromatography. Under the conditions studied, isolated oligomers were shown to be resistant to fibrillation or dissociation. These oligomers contain between two and five polypeptide chains and they have a highly disordered structure as indicated by a variety of spectroscopic techniques. They are highly stable with respect to time, temperature, or agitation despite their noncovalent character, which was established using liquid chromatography-mass spectrometry and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These results provide evidence of stable, low-molecular-weight oligomers that are formed by an off-pathway mechanism which competes with amyloid fibril formation.
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http://dx.doi.org/10.1016/j.bpj.2023.04.027 | DOI Listing |
Neurobiol Dis
December 2024
Department of Neurology, Kanazawa University Graduate School of Medical Sciences, 13-1, Kanazawa 920-8640, Japan. Electronic address:
The accumulation of amyloid β-proteins (Aβ) in the extracellular space, forming insoluble plaques, is a primary pathological process underlying Alzheimer's disease (AD). Among the various Aβ species that appear during Aβ aggregation, Aβ oligomers are considered the most neurotoxic form. However, the precise mechanisms of their molecular functions within the Aβ aggregation cascade have not been clarified so far.
View Article and Find Full Text PDFBiol Pharm Bull
December 2024
Institute of Life and Environmental Sciences, University of Tsukuba.
Amyloid polypeptide aggregation is considered one of the factors involved in the pathogenesis of Alzheimer's disease (AD) and type 2 diabetes (T2D), and the number of affected patients increases as the population ages. Amyloid β (Aβ) found in the brain of patients with AD and human islet amyloid polypeptide (hIAPP) found in the pancreas of patients with T2D are thought to be cytotoxic during the aggregation process, especially the low-molecular-weight oligomers that are aggregation intermediates. In this study, meroterpenoids isolated and structurally determined from the brown alga Sargassum macrocarpum were evaluated for their ability to inhibit hIAPP aggregation.
View Article and Find Full Text PDFJ Alzheimers Dis
November 2024
Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA.
Background: Insulin-like growth factor-1 (IGF-1) promotes neurogenesis, cell survival, and glial function, making it a promising candidate therapy in Alzheimer's disease (AD).
Objective: Long arginine 3-IGF-1 (LR3-IGF-1) is a potent IGF-1 analogue. We sought to determine whether intranasal (IN) LR3 treatment would delay cognitive decline and pathology in 5XFAD mice.
Antioxidants (Basel)
November 2024
Department of Biochemistry & Molecular Medicine, University of California, Davis, CA 95616, USA.
The disorder and heterogeneity of low-molecular-weight amyloid-beta oligomers (AβOs) underlie their participation in multiple modes of cellular dysfunction associated with the etiology of Alzheimer's disease (AD). The lack of specified conformational states in these species complicates efforts to select or design small molecules to targeting discrete pathogenic states. Furthermore, targeting AβOs alone may be therapeutically insufficient, as AD progresses as a multifactorial, self-amplifying cascade.
View Article and Find Full Text PDFChembiochem
January 2025
Laboratory of biophysics, National University of Science and Technology MISIS, Leninskiy ave. 4, Moscow, 119049, Russia.
This study aims to investigate the potential role of antioxidants in oxidative stress and its consequent impact on the mechanical properties of neuronal cells, particularly the stress induced by amyloid-beta (1-42) (Aβ) aggregates. A key aspect of our research involved using scanning ion-conductance microscopy (SICM) to assess the mechanical properties (Young's modulus) of neuronal cells under oxidative stress. Reactive oxygen species (ROS) level was measured in single-cell using the electrochemical method by low-invasive Pt nanoelectrode.
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