| First Author | Simões AT | Year | 2012 |
| Journal | Brain | Volume | 135 |
| Issue | Pt 8 | Pages | 2428-39 |
| PubMed ID | 22843411 | Mgi Jnum | J:318907 |
| Mgi Id | MGI:6861895 | Doi | 10.1093/brain/aws177 |
| Citation | Simoes AT, et al. (2012) Calpastatin-mediated inhibition of calpains in the mouse brain prevents mutant ataxin 3 proteolysis, nuclear localization and aggregation, relieving Machado-Joseph disease. Brain 135(Pt 8):2428-39 |
| abstractText | Machado-Joseph disease is the most frequently found dominantly-inherited cerebellar ataxia. Over-repetition of a CAG trinucleotide in the MJD1 gene translates into a polyglutamine tract within the ataxin 3 protein, which upon proteolysis may trigger Machado-Joseph disease. We investigated the role of calpains in the generation of toxic ataxin 3 fragments and pathogenesis of Machado-Joseph disease. For this purpose, we inhibited calpain activity in mouse models of Machado-Joseph disease by overexpressing the endogenous calpain-inhibitor calpastatin. Calpain blockage reduced the size and number of mutant ataxin 3 inclusions, neuronal dysfunction and neurodegeneration. By reducing fragmentation of ataxin 3, calpastatin overexpression modified the subcellular localization of mutant ataxin 3 restraining the protein in the cytoplasm, reducing aggregation and nuclear toxicity and overcoming calpastatin depletion observed upon mutant ataxin 3 expression. Our findings are the first in vivo proof that mutant ataxin 3 proteolysis by calpains mediates its translocation to the nucleus, aggregation and toxicity and that inhibition of calpains may provide an effective therapy for Machado-Joseph disease. |
