Thesis title: Small molecules loaded on nanocarriers protecting from amyloid neurotoxicity
Biological issue Misfolding of amyloid proteins results in a self-assembling process where metastable, soluble prefibrillar oligomers (PFOs) are the most neurotoxic intermediates. Previously, we proposed the innovative “amyloid mediated excitotoxicity” paradigm, where PFOs interaction with GM-1 enriched lipid rafts, on neuronal membranes, induces the formation of low conductance-amyloid pores and the subsequent calcium overload results in NMDARs-mediated excitotoxicity.
Currently, no consensus has been reached on the therapeutic implications of monoclonal antibodies against amyloid-related diseases. Here, we propose a new pharmacological approach based on the protective effects of small diffusible and biocompatible compounds able both to interfere in the PFOs interactions with lipid membranes and to disaggregate them down to non-toxic species.
Results. We first successfully found the optimal aggregation conditions for salmon Calcitonin (sCT) amyloid aggregates yielding a substantial amount of highly cytotoxic oligomers. Then we Investigated the EPPS disaggregating properties; we found that EPPS can disassemble PFOs into non-toxic species. Moreover, we demonstrated that EPPS effectively act also on amyloid fibres, thus is able to affect both the primary and secondary nucleation. We also confirmed that GM1 is a pivotal player in the amyloid toxicity since a NAA treatment restored the cellular viability to the controls, in primary hippocampal neurons.
Conclusions EPPS and NAA represent good candidates as drugs against early amyloid toxicity. In the next future, my results will be pivotal to administer a mixture of EPPS and NAA-loaded liposomes to directly reach target sites in the Central Nervous System.
Keywords: misfolding, prefibrillar oligomers, amyloid toxicity, membrane damage, neurodegeneration