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

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.

The Office for National Statistics shows that dementia is among the most common causes of death in the United Kingdom. Worldwide, approximately 50 million people suffer from dementia, and that this number will rise to 150 millions by 2050, unless a cure or effective treatments are found. Furthermore, the annual cost of these diseases to the UK economy exceeds £20 billion, which equals that of cancer and heart disorders combined, and are set to increase steadily in the future as the average human life expectancy extends.

Despite its high prevalence and societal costs, dementia receives a disproportionally small fraction of funding as compared to other diseases. There is currently only one dementia researcher in the UK for every four cancer researchers. This is due, in part, to the fact that the associated molecular markers and mechanisms of dementia are poorly defined and, consequently, dementia is still seen as part of 'normal' aging. My goal is to change this paradigm by unveiling the key molecular mechanisms of the pathology and creating molecules (such as antibodies) that could be translated into diagnostic and research tools to directly benefit society at different levels.

The stakeholders in this proposal include researchers, industrial scientists, medical doctors, and, most importantly, those directly affected by dementia. Researchers are likely to be the first to benefit from my work, as the insights that I will obtain regarding the effect of PTMs on the formation and toxicity of amyloids will shape future biomedical research. Furthermore, the antibody tools that I will produce will be widely shared within the scientific community to extend the scope of the study to new systems and models.

Secondly, it is my aim to develop the most promising antibodies with high specificities towards toxic amyloid aggregates into diagnostic tools. Currently, there is no simple biometric test for dementia. Instead, the diagnosis involves and extremely lengthy procedure based on behavioral and psychological evaluations. Very often this procedure can produce inconclusive and misleading results, making it extremely difficult to plan intervention and therapeutic approaches. The development of a fast diagnostic method that could be used to establish early onset of neurodegenerative disease would produce significant medical, emotional, and social benefit, and would also result in significant savings in medical and long-term care for both governments and diagnosed individuals.

Lastly, my research has the potential to be extended into of novel therapeutic strategies against these pathologies. Not only will a detailed understanding of the amyloid process in vivo create new avenues for therapeutic intervention by identifying new toxic species, but also the antibodies themselves may be further developed into therapeutic molecules to be integrated into clinical protocols. These outcomes will be achieved by developing a highly innovative antibody-discovery platform, which combines both computation and experiment. This platform will enable the production of antibodies that are readily able to target any given epitope in any conformation with a given chemical modification. This advance will enable scientists to bypass lengthy production procedures, which can take years, and instead produce biologically relevant molecules in a matter of months.

As a result of their strong binding abilities and high specificities, antibodies have recently become key tools in biomedical research and diagnostics, and represent the fastest-growing class of protein therapeutics on the market against cancer, autoimmune diseases, and neurodegeneration. The therapeutic antibody market is projected to steadily rise for the next several years, and it is expected to reach $125 billions by 2020. The technology I will create will open novel opportunities in all these sectors, and will eventually contribute and will benefit society in a way far beyond dementia.