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Synucleinopathies are a group of disorders characterized by the accumulation of a-Synuclein amyloid inclusions in the brain. Preventing a-Synuclein aggregation is challenging because of the disordered nature of the protein and the stochastic nature of fibrillogenesis, but, at the same time, it is a promising approach for therapeutic intervention in these pathologies. A high-throughput screening initiative allowed us to discover ZPDm, the smallest active molecule in a library of more than 14.000 compounds. Although the ZPDm structure is highly related to that of the previously described ZPD-2 aggregation inhibitor, we show here that their mechanisms of action are entirely different. ZPDm inhibits the aggregation of wild-type, A30P, and H50Q a-Synuclein variants in vitro and interferes with a-Synuclein seeded aggregation in protein misfolding cyclic amplification assays. However, ZPDm distinctive feature is its strong potency to dismantle preformed a-Synuclein amyloid fibrils. Studies in a Caenorhabditis elegans model of Parkinson’s Disease, prove that these in vitro properties are translated into a significant reduction in the accumulation of a-Synuclein inclusions in ZPDm treated animals. Together with previous data, the present work illustrates how different chemical groups on top of a common molecular scaffold can result in divergent but complementary anti-amyloid activities.

Parkinson''s disease (PD) is characterized by a progressive loss of dopaminergic neurons, a process that current therapeutic approaches cannot prevent. In PD, the typical pathological hallmark is the accumulation of intracellular protein inclusions, known as Lewy bodies and Lewy neurites, which are mainly composed of alpha-synuclein. Here, we exploited a high-throughput screening methodology to identify a small molecule (SynuClean-D) able to inhibit alpha-synuclein aggregation. SynuClean-D significantly reduces the in vitro aggregation of wildtype alpha-synuclein and the familiar A30P and H50Q variants in a substoichiometric molar ratio. This compound prevents fibril propagation in protein-misfolding cyclic amplification assays and decreases the number of alpha-synuclein inclusions in human neuroglioma cells. Computational analysis suggests that SynuClean-D can bind to cavities in mature alpha-synuclein fibrils and, indeed, it displays a strong fibril disaggregation activity. The treatment with SynuClean-D of two PD Caenorhabditis elegans models, expressing alpha-synuclein either in muscle or in dopaminergic neurons, significantly reduces the toxicity exerted by alpha- synuclein. SynuClean-D-treated worms show decreased alpha-synuclein aggregation in muscle and a concomitant motility recovery. More importantly, this compound is able to rescue dopaminergic neurons from alpha-synuclein-induced degeneration. Overall, SynuClean-D appears to be a promising molecule for therapeutic intervention in Parkinson's disease.

Trabajo presentado en el 6th International Symposium on Emerging and Re-emerging pig Diseases, celebrado en Barcelona (España) del 12 al 15 de julio de 2011.