Targeting Alpha-Synuclein for treating Multiple System Atrophy (ARTEMIS)

Multiple system atrophy is a fatal disorder with severe motor impairment and dysautonomia affecting over 30,000 people in Europe. Accumulation of a-synuclein in oligodendrocytes plays a pivotal role, leading to glial and neuronal dysfunction and degeneration. These features are recapitulated in the PLP-SYN mouse model expressing a-synuclein in oligodendrocytes. This project aims at counteracting disease progression by targeting key mechanisms contributing to a-synuclein accumulation. Using complementary in-vitro and in-vivo models, we will test the efficacy of: 1) increasing a-synuclein clearance by activating autophagy with rapamycin, 2) reducing seeding of aggregation by preventing its cleavage with VX-765, 3) reducing a-synuclein aggregation using the oligomer inhibitor anle138b, and 4) preventing a-synuclein propagation via active and passive immunotherapy using AFFITOPE. Finally, we will test the combination of the most promising strategies to obtain synergistic therapeutic effect. Efficacy readouts will include oxidative stress, unfolded protein response (in-vitro), cell survival, monomeric, oligomeric and post-translational modifications of a-synuclein (in-vitro and in-vivo), astroglial and microglial activation, as well as motor deficits (in-vivo). This project involves academic partners with strong expertise in multiple system atrophy and industrial partners with innovative therapeutic candidates. This unique combination at the European level will allow a rapid translation of successful strategies into clinical trials.

The project tested whether candidate interventions including Anle138b, AFFITOPEs, and combined Anle138b and AFFITOPEs are effective in the PLP-aSyn mouse model of multiple system atrophy (MSA) The experimental results provide a preclinical rationale for disease modifying therapies targeting -synuclein (-syn) pathology in MSA. Anle 138b is a small molecule inhibiting -synuclein (-syn) oligomerization and aggregation. Anle 138b can be delivered orally and penetrates the blood brain barrier, entering the brain with high efficacy. It is characterized by high bioavailability and low toxicity. We hypothesized that Anle138b may attenuate disease progression in MSA. PLP-aSyn mice treated with Anle138b maintained normal motor function, showed preserved dopaminergic neurons in the SNc and significant reduction of -syn inclusions. Anle138b reduced microglial activation in the SN back to its normal levels as observed in healthy control mice. Initial studies in synucleinopathy mouse models demonstrated the efficacy of the AFFITOPE approach to trigger specific antibody generation with CNS penetrance and lowering of -syn aggregates and oligomers which led to neuroprotection and had beneficial effect on locomotor behaviour. In our second experiment we compared for the first time the in vivo effects of two different AFFITOPEs side-by-side in a mouse model of synucleinoapthy and demonstrated differential efficacy. The treatment ameliorated the motor deficits, and was linked to rescue of dopaminergic neurons in SNc in this model of MSA. The reduction of -syn oligomeric species after AFFITOPE therapy was associated with a reduction of microglial activation in the PLP--syn brain. In a third experiment we combined Anle138b and AFFITOPE for the treatment of PLP-aSyn mice to identify potential interactions between the two approaches. Similar to single therapies, the combination provided motor improvement, rescue of dopaminergic neurons in SNc, reduction of the -syn aggregates and suppression of microglial activation without a cumulative or antagonizing effect of the two approaches. The study provided indirect information about the shared target engagement of Anle 138b and AFFITOPE.