# An Overview of Glutaminyl Cyclase as a Promising Drug Target for Alzheimer’s Disease

## TL;DR

This paper reviews glutaminyl cyclase as a new drug target for Alzheimer's disease, focusing on how inhibiting it could prevent harmful amyloid plaque formation.

## Contribution

The paper provides an overview of glutaminyl cyclase inhibition as a novel therapeutic strategy for Alzheimer’s disease.

## Key findings

- Glutaminyl cyclase inhibition prevents the formation of pyroglutamated Aβ, a key seed for amyloid plaques.
- Imidazole-based inhibitors have been developed and optimized, with Varoglutamstat entering clinical trials.
- Future research aims to improve the specificity and potency of glutaminyl cyclase inhibitors.

## Abstract

Alzheimer’s disease (AD) has become an increasingly pressing concern for the aging population. Current AD treatments mainly focus on cognitive and neuropsychiatric symptoms—with few FDA-approved treatments targeting disease progression itself. The amyloid cascade hypothesis describes the formation and accumulation of β-amyloid (Aβ) oligomers and plaques as a primary event in AD pathogenesis. This hypothesis has served as the foundation of disease-modifying treatment development over the last decade. Recently, glutaminyl cyclase (QC) has been identified as a potential drug target in the amyloid cascade. QC catalyzes the cyclization of Aβ to form pyroglutamated Aβ (pEAβ). pEAβ acts as the seed for the formation of Aβ plaques, thus preventing the formation of pEAβ via QC inhibition, and offers a promising therapeutic strategy against AD. Here, we offer an overview of the pathway QCI research has followed—from the initial testing of imidazole-based inhibitor scaffolds to QCI structural optimization via pharmacophore identification, Varoglutamstat entering clinical trials, and further avenues of bettering specificity and potency for future QCI development.