Novel Small-Molecule Analogues of IU1 Ameliorate Amyloid-β Mediated Toxicity in Alzheimer's Disease Cell and Worm Models.

Dysregulation of the deubiquitinating enzyme Ubiquitin-specific peptidase 14 (USP14) is implicated in several neurodegenerative diseases, and IU1, an allosteric inhibitor, has shown neuroprotective effects by reducing protein aggregate toxicity. This study aimed to develop new IU1 analogues and evaluate their ability to mitigate amyloid-β (Aβ) accumulation and toxicity in Alzheimer's disease (AD) cell and Caenorhabditis elegans worm models. IU1 and 71 newly designed analogues identified using the AtomNet® virtual screening platform were assessed in an amyloid precursor protein-C terminal fragment/amyloid-β (APP-C99/Aβ)-producing AD cell model using a high-throughput toxicity assay. Lead compounds were further evaluated for their effects on neurodegeneration, behaviour, and survival. IU1 reduced Aβ-mediated toxicity and neurodegeneration in cell and worm models. Of the 71 analogues predicted to bind ubiquitin-specific peptidase 14 (USP14), two compounds, AA10 and AA51, showed >50% rescue of Aβ-induced toxicity and robust enhancement of autophagy and proteasome activity. In Caenorhabditis elegans, both compounds alleviated glutamatergic neuron loss and rescued behavioural impairments. IU1 and analogues exhibit protective effects against Aβ toxicity in AD models. Analogues AA10 and AA51 showed greater potency than IU1 and effectively enhanced proteostasis pathways. These findings support USP14 as a promising therapeutic target and provide a basis for the development of improved IU1-derived compounds for AD and related disorders.