Probing Post-Translational Modification in Neurodegenerative Protein Aggregation with a Novel Antibody-Based Technology

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Dementia, including Alzheimer's disease, is among the most common causes of death in the U.K. Worldwide, it is estimated that 50 million people suffer from dementia, and that this number will rise to 150 million by 2050 unless effective treatments are found. The formation of amyloid aggregates is a hallmark of many of these pathologies. In the last decade, research efforts have focused on understanding the aggregation process and the associated toxicity caused by monitoring amyloid formation of a single protein in isolation under highly controlled conditions. This approach helped unveil the physical phenomena that regulate amyloid formation; nevertheless, often it provides overly simplistic descriptions of the process, as it fails to account for the contributions of many coordinated events that occur in the human body. The most striking evidence of this fact is the observation that aggregates formed in vitro are significantly different from those observed in patients, which, for example, show multiple chemical modifications (also called post-translational modifications or PTMs), which likely arise as a result of the interactions of these proteins within the complex environment of the brain.In theory, antibodies are ideal tools to accurately investigate amyloid processes, as they can be used for both highly quantitative in vitro studies and imaging of complex biological samples. As such, antibodies could, in principle, enable a high level of interdisciplinarity, which is necessary to extrapolate complex information intricate biological systems. Nevertheless, despite their potential, the use of antibodies in the amyloid field is currently hindered by several challenges linked to their production. In particular, current antibody-discovery strategies do not always allow one to target specific protein regions (i.e. epitopes) a priori or to target specific chemical features (such as modified epitopes) or conformations (such as aggregated).As a UKRI Future Leader Fellow at the Department of Chemistry of Imperial College London, my goal will be to develop an innovative antibody-discovery platform, which combines molecular and chemical biology with protein design. I will exploit this platform to characterise the mechanisms of formation and nature of amyloids formed in vivo. In particular, I will use this platform to generate antibodies to understand the role of PTMs in the amyloid aggregation process.A vast body of literature has identified PTMs of amyloid proteins in people affected by dementia. As the exact role of PTMs in amyloid formation and toxicity has yet to be determined, current drug discovery approaches generally disregard PTMs and are based on unmodified proteins. Nevertheless, such drug discovery approaches have yet to lead to a cure. PTMs represent an unexplored opportunity for therapeutic intervention and diagnosis of dementia. Despite their clinical promise, PTMs are difficult to characterise in biological contexts due to the complex makeup of in vivo samples. The high specificity and affinity afforded by antibodies make them perfect probes for identifying and localising PTMs in heterogeneous contexts.To understand the relevance of PTMs in dementia, I propose to generate antibodies that target specific PTM-amyloids, which is currently not possible with state-of-the-art methodology. I will then use these antibodies to study aggregates from biological samples and to determine which modifications are responsible for the formation and toxicity of these self-assemblies. To do so, I will combine biophysical methods (such as protein aggregation studies), imaging on biological samples, and C. elegans studies.The results of this study will enable the identification of new pathological mechanisms and biomarkers towards novel diagnostic and therapeutic approaches against dementia.