Trinucleotide CAG repeat expansion in the coding region of genes has a propensity to form polyglutamine (polyQ) aggregates that contribute to neuronal disorders. Strategies in elevating autophagy to disintegrate the insoluble aggregates without injuring cells have become a major goal for therapy. In this work, a triazole derivative, OC-13, was found accelerating autophagic clearance of polyQ aggregation in human neuroblastoma cells following induction of the enhanced green fluorescence-conjugated chimeric protein that enclosed 79 polyQ repeats (Q79-EGFP). OC-13 accelerated autophagy development and removed nuclear Q79-EGFP aggregates. The increase of Beclin-1, turnover of LC3-I to LC3-II and degradation of p62 supported autophagy activation. Pretreatment of autophagy inhibitor, bafilomycin A1, not only suppressed autophagolysome fusion, but also impeded aggregate eradication. The study also showed that c-Jun N-terminal kinase/Beclin-1 pathway was activated during OC-13 treatment and c-Jun N-terminal kinase inhibitor impaired autophagy and final breakdown. Autophagic clearance of the insoluble aggregates demonstrated the feasibility of OC-13 in alleviating neuronal disorders because of expanded glutamine stretches.
Keywords: JNK pathway; aggregates clearance; autophagic flux; green fluorescence protein; neuronal disorders; polyglutamine; triazole.