Glucagon-Like Peptide-1 Receptor Agonists Inhibit the Initiation of Toxic Amyloid-β42 Aggregation.
This study investigated whether five FDA-approved glucagon-like peptide-1 receptor agonists (GLP-1RAs) — semaglutide, tirzepatide, liraglutide, and two others — could directly inhibit the aggregation of the 42-residue amyloid-β peptide (Aβ42), a key process implicated in Alzheimer's disease (AD). Using in vitro aggregation kinetics and microscopic analysis, researchers found that semaglutide, tirzepatide, and liraglutide inhibited Aβ42 aggregation, primarily by targeting the primary nucleation step — the initial formation of amyloid seeds. Semaglutide and tirzepatide delayed aggregation with submicromolar potency, while liraglutide showed the strongest suppression of primary nucleation and additionally modestly inhibited secondary nucleation. Liraglutide also altered fibril structure — producing less mature, more tortuous, and longer fibrils — and reduced the ability of fibrils to self-replicate (template). The study was conducted entirely in vitro (no cell, animal, or human data), which is a significant limitation for clinical translation. The authors conclude that certain GLP-1RAs can directly interfere with molecular steps of Aβ42 aggregation, and call for further studies to determine whether these mechanisms contribute to potential AD-protective effects observed in preclinical and clinical research.
Why this grade: All experiments were performed in cell-free, test-tube aggregation assays; no animal models or human subjects were involved, limiting direct inference about clinical efficacy.
The aggregation of the 42-residue form of the amyloid-β peptide (Aβ 42 ) is important in Alzheimer's disease (AD). Preclinical and clinical findings support that glucagon-like peptide-1 receptor agonists (GLP-1RAs) can protect against neuroinflammation and neurodegeneration with potential therapeutic relevance for AD, but studies of their direct effects on Aβ 42 are limited. Herein, we investigated five FDA-approved GLP-1RAs, and show semaglutide, tirzepatide, and liraglutide inhibit Aβ 42 aggregation. Semaglutide and tirzepatide delayed Aβ 42 aggregation by targeting the primary nucleation microscopic step, with submicromolar IC 50 values for primary nucleation ( K IP ). Liraglutide was highly effective at suppressing primary nucleation with a very low K IP value, and it demonstrated an additional modest inhibition of secondary nucleation. Consistent with a dominant effect on primary nucleation, Aβ 42 formed β-sheet-rich fibrils in the presence of these GLP-1RAs. Aβ 42 fibrils formed with semaglutide or tirzepatide had morphological properties and templating efficiencies that were similar to unmodified fibrils, while liraglutide significantly reduced fibril maturity, increased fibril tortuosity and length, and attenuated the ability of fibrils to passively self-replicate whether they were formed in the presence of liraglutide or exposed to this GLP-1RA after their formation. These results provide molecular-level insight into how specific GLP-1RAs can selectively target the fundamental steps governing toxic Aβ 42 aggregation. Further studies are warranted to determine if current or next-generation anti-amyloid GLP-1RAs can delay or prevent AD through multifaceted protective mechanisms, including the direct inhibition of Aβ 42 aggregation.
Educational summary of published research — not medical advice. License: cc by. Full text is shown only where licensing permits.