Luis Pereira de Almeida
Partner Luis Pereira de Almeida provided evidence of the implication of autophagy in the accumulation of mutant ATXN3 aggregates and neurodegeneration in Machado-Joseph disease and demonstrated that specific stimulation of this pathway by overexpression of beclin-1 could mitigate the disease. Using tissue from MJD patients, transgenic mice and a lentiviral-based rat model, LPA and col. found abnormal levels of endogenous autophagic markers, accumulation of autophagosomes and decreased levels of beclin-1. Lentiviral vectors-mediated overexpression of beclin-1 led to stimulation of autophagic flux, mutant ATXN3 clearance and overall neuroprotective effects in vitro and in vivo. These data demonstrate that autophagy is a key degradation pathway, with beclin-1 playing a significant role in alleviating Machado-Joseph disease pathogenesis (Nascimento-Ferreira et al., Brain, 2011, 2013).
The project will take advantage of the available expertise with lentiviral vectors for production of models of disease and study of disease-modifying approaches (de Almeida et al., J Neurosci, 2002; Alves et al., Hum Mol Genet, 2008b and PLoS One, 2008a; Simoes et al Brain, Gonçalves et al Annals of Neurology 2013) aiming at answering the questions: How is the autophagy pathway regulated in MJD? Which autophagy-related genes are down or up-regulated in MJD? Which specific molecular pathway is impaired? Which specific pathways should be modulated to obtain therapeutic effects?
Autophagy is impaired in Machado-Joseph disease (MJD) and its activation alleviates neuropathology and motor impairments. A. Abnormal accumulation of autophagosomes in post mortem MJD brain tissue suggests impairments in autophagy in MJD. B- Levels of beclin-1, a protein involved in early and late stages of autophagy are decreased in MJD fibroblasts. Overexpression of beclin-1 promotes clearance of mutant ataxin-3 oligomers and aggregates in striatal cultures. D- Lentiviral-mediated overexpression of beclin-1 prevents loss of brain markers such as darpp-32 in a lentiviral mouse model of MJD. Beclin-1 overexpression alleviates motor impairments robustly increasing performance of transgenic mice in the rotarod test. Data from Nascimento-Ferreira et al Brain 2011 and 2013.