Modulating the catalytic activity of AMPK has neuroprotective effects against α-synuclein toxicity

Wojciech Bobela, Sameer Nazeeruddin, Graham Knott, Patrick Aebischer, Bernard L. Schneider

Metabolic perturbations and slower renewal of cellular components associated with aging increase the risk of Parkinson's disease (PD). Declining activity of AMPK, a critical cellular energy sensor, may therefore contribute to neurodegeneration. Here, we overexpress various genetic variants of the catalytic AMPKα subunit to determine how AMPK activity affects the survival and function of neurons overexpressing human α-synuclein in vivo. Both AMPKα1 and α2 subunits have neuroprotective effects against human α-synuclein toxicity in nigral dopaminergic neurons. Remarkably, a modified variant of AMPKα1 (T172Dα1) with constitutive low activity most effectively prevents the loss of dopamine neurons, as well as the motor impairments caused by α-synuclein accumulation. In the striatum, T172Dα1 decreases the formation of dystrophic axons, which contain aggregated α-synuclein. In primary cortical neurons, overexpression of human α-synuclein perturbs mitochondrial and lysosomal activities. Co-expressing AMPKα with α-synuclein induces compensatory changes, which limit the accumulation of lysosomal material and increase the mitochondrial mass. Together, these results indicate that modulating AMPK activity can mitigate α-synuclein toxicity in nigral dopamine neurons, which may have implications for the development of neuroprotective treatments against PD.