Article: article from journal or magazin.
Overexpression of the autophagic beclin-1 protein clears mutant ataxin-3 and alleviates Machado-Joseph disease.
Publication types: Journal Article ; Research Support, Non-U.S. Gov'tPublication Status: ppublish
Machado-Joseph disease, also known as spinocerebellar ataxia type 3, is the most common of the dominantly inherited ataxias worldwide and is characterized by mutant ataxin-3 misfolding, intracellular accumulation of aggregates and neuronal degeneration. Here we investigated the implication of autophagy, the major pathway for organelle and protein turnover, in the accumulation of mutant ataxin-3 aggregates and neurodegeneration found in Machado-Joseph disease and we assessed whether specific stimulation of this pathway could mitigate the disease. Using tissue from patients with Machado-Joseph disease, transgenic mice and a lentiviral-based rat model, we found an abnormal expression of endogenous autophagic markers, accumulation of autophagosomes and decreased levels of beclin-1, a crucial protein in the early nucleation step of autophagy. Lentiviral vector-mediated overexpression of beclin-1 led to stimulation of autophagic flux, mutant ataxin-3 clearance and overall neuroprotective effects in neuronal cultures and in a lentiviral-based rat model of Machado-Joseph disease. These data demonstrate that autophagy is a key degradation pathway, with beclin-1 playing a significant role in alleviating Machado-Joseph disease pathogenesis.
Aged, Animals, Apoptosis Regulatory Proteins/genetics, Apoptosis Regulatory Proteins/metabolism, Autophagy/genetics, Brain/metabolism, Brain/pathology, Carrier Proteins/genetics, Cell Line, Tumor, Female, Flow Cytometry, Gene Expression Regulation/genetics, Humans, Machado-Joseph Disease/genetics, Machado-Joseph Disease/pathology, Male, Membrane Proteins/genetics, Membrane Proteins/metabolism, Mice, Mice, Inbred C57BL, Mice, Transgenic, Middle Aged, Mutation/genetics, Nerve Tissue Proteins/genetics, Nuclear Proteins/genetics, RNA-Binding Proteins/genetics, Rats, Rats, Wistar, Repressor Proteins/genetics, Transfection/methods, Trinucleotide Repeat Expansion/genetics
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