Clearance of Aggresome‐Like Inclusion Bodies from SK‐N‐SH Human Neuroblastoma Cells through Increasing Autophagic Flux

Pathological inclusion bodies containing aggregated proteins are characteristic of various neurodegenerative diseases, including Parkinson's, Alzheimer's and Huntington's disease. Aggresomes and related inclusion bodies may serve as storage depots for the disposal of toxic protein aggregates by the autophagy pathway. One strategy for reducing cytotoxicity associated with aggregated protein accumulation is by enhancing their clearance through activation of autophagy. The SK‐N‐SH human neuroblastoma cell line was induced to form inclusion bodies by incubation with amyloid beta 1–42 peptide, thus mimicking the accumulation of â‐amyloid within neurons in Alzheimer's disease. Members of a focused compound library, containing well‐characterized small molecules with defined modes of action relevant to autophagy, were screened for their impact upon inclusion body accumulation using a fluorogenic dye that selectively highlights aggregated protein cargo. Certain compounds, such as chloroquine, promoted aggregate accumulation. Others, like SMER28, an inducer of autophagy that acts via an mTOR‐independent mechanism to increase autophagosome synthesis and enhance autophagic flux, reduced accumulation of â‐amyloid peptide within the cells. The described cell‐based screening assay facilitates identification of activators of autophagic flux that promote clearance of aggregated protein cargo.