Pyroglutamate-Mediated Mechanisms in Alzheimer's Disease

In Alzheimer’s disease, a subset of amyloid-β (Aβ) peptides undergoes N-terminal truncation followed by cyclisation to form pyroglutamate (pGlu) residues, most notably at positions 3 and 11. This modification is catalysed by the enzyme glutaminyl cyclase, which converts an N-terminal glutamine or glutamate into a cyclic pyroglutamate moiety. The resulting pGlu-Aβ species display enhanced hydrophobicity, resistance to proteolytic degradation and a remarkable propensity to form soluble oligomers. These oligomers are implicated in synaptic dysfunction, neuronal toxicity and downstream tau pathology. Their stabilised assembly accelerates plaque seeding and promotes neuroinflammation, contributing to the characteristic cognitive decline of Alzheimer’s disease. Recent efforts aim to delineate the precise biophysical properties of pGlu-Aβ aggregates, to visualise glutaminyl cyclase activity in vivo and to intercept pyroglutamate formation through small-molecule inhibitors or immunotherapy. Understanding these mechanisms holds potential for novel diagnostics and targeted interventions that disrupt a critical early step in the amyloid cascade.

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Pyroglutamate-Mediated Mechanisms in Alzheimer's Disease publication trend

The graph below shows the total number of articles in pyroglutamate-mediated mechanisms in alzheimer's disease across all publications each year (not limited to Nature Index journals).

Technical terms

Pyroglutamate (pGlu): A cyclic derivative of glutamine or glutamate formed by intramolecular cyclisation at the N-terminus of a peptide.

Glutaminyl cyclase: An enzyme that catalyses the conversion of N-terminal glutamine or glutamate residues into pyroglutamate, enhancing peptide stability and aggregation propensity.

Aβ oligomer: A soluble assembly of amyloid-β monomers, intermediate in the pathway to fibril and plaque formation, often associated with neurotoxicity.

N-terminal truncation: Proteolytic removal of one or more amino acids from the N-terminus of a protein or peptide, which can expose residues for further modification.

Immunotherapy: The use of antibodies to selectively bind pathological protein species—in this context, pyroglutamate-modified Aβ—to promote their clearance or neutralisation.

References

1. Synthesis and Evaluation of a Novel PET Radioligand for Imaging Glutaminyl Cyclase Activity as a Biomarker for Detecting Alzheimer’s Disease. ACS Sensors (2024).
2. Therapeutic potential of glutaminyl cyclases: Current status and emerging trends. Drug Discovery Today (2023).
3. Overexpression of Glutaminyl Cyclase, the Enzyme Responsible for Pyroglutamate Aβ Formation, Induces Behavioral Deficits, and Glutaminyl Cyclase Knock-out Rescues the Behavioral Phenotype in 5XFAD Mice*. Journal of Biological Chemistry (2010).
4. Pyroglutamate Aβ cascade as drug target in Alzheimer’s disease. Molecular Psychiatry (2021).
5. Pyroglutamate Amyloid-β (Aβ): A Hatchet Man in Alzheimer Disease*. Journal of Biological Chemistry (2011).
6. Glutaminyl Cyclase Inhibitor PQ912 Improves Cognition in Mouse Models of Alzheimer’s Disease—Studies on Relation to Effective Target Occupancy. Journal of Pharmacology and Experimental Therapeutics (2017).