TY - JOUR

T1 - Enhancement of Autophagy and Solubilization of Ataxin-2 Alleviate Apoptosis in Spinocerebellar Ataxia Type 2 Patient Cells

AU - Wardman, Jonathan Henry

AU - Henriksen, Emil Elbæk

AU - Marthaler, Adele Gabriele

AU - Nielsen, Jørgen Erik

AU - Nielsen, Troels Tolstrup

PY - 2020/4

Y1 - 2020/4

N2 - Spinocerebellar ataxia type 2 (SCA2), a rare polyglutamine neurodegenerative disorder caused by a CAG repeat expansion in the ataxin-2 gene, exhibits common cellular phenotypes with other neurodegenerative disorders, including oxidative stress and mitochondrial dysfunction. Here, we show that SCA2 patient cells exhibit higher levels of caspase-8- and caspase-9-mediated apoptotic activation than control cells, cellular phenotypes that we find to be exacerbated by reactive oxygen species (ROS) and inhibition of autophagy. We also suggest that oligomerization of mutant ataxin-2 protein is likely to be the cause of the observed cellular phenotypes by causing inhibition of autophagy and by inducing ROS generation. Finally, we show that removal of ataxin-2 oligomers, either by increasing autophagic clearance or by oligomer dissolution, appears to alleviate the cellular phenotypes. Our results suggest that oligomerized ataxin-2 and oxidative stress affect autophagic clearance in SCA2 cells, contributing to the pathophysiology, and that activation of autophagy or clearance of oligomers may prove to be effective therapeutic strategies.

AB - Spinocerebellar ataxia type 2 (SCA2), a rare polyglutamine neurodegenerative disorder caused by a CAG repeat expansion in the ataxin-2 gene, exhibits common cellular phenotypes with other neurodegenerative disorders, including oxidative stress and mitochondrial dysfunction. Here, we show that SCA2 patient cells exhibit higher levels of caspase-8- and caspase-9-mediated apoptotic activation than control cells, cellular phenotypes that we find to be exacerbated by reactive oxygen species (ROS) and inhibition of autophagy. We also suggest that oligomerization of mutant ataxin-2 protein is likely to be the cause of the observed cellular phenotypes by causing inhibition of autophagy and by inducing ROS generation. Finally, we show that removal of ataxin-2 oligomers, either by increasing autophagic clearance or by oligomer dissolution, appears to alleviate the cellular phenotypes. Our results suggest that oligomerized ataxin-2 and oxidative stress affect autophagic clearance in SCA2 cells, contributing to the pathophysiology, and that activation of autophagy or clearance of oligomers may prove to be effective therapeutic strategies.

U2 - 10.1007/s12311-019-01092-8

DO - 10.1007/s12311-019-01092-8

M3 - Journal article

C2 - 31898278

VL - 19

SP - 165

EP - 181

JO - Cerebellum (London, England)

JF - Cerebellum (London, England)

SN - 1473-4222

IS - 2

ER -