Understanding the Critical Step for the Cellular Toxicity of Protein Oligomers.

Protein molecules have evolved to attain functional and soluble states under normal and physiological conditions. In some cases, however, some protein molecules are unable to remain stable as monomers and consequently associate into protein aggregates having a fibrilar nature. These aggregates, designated as amyloids, have a large biological relevance and are in fact considered attractive structures for targeting new generations of biomaterials. Early states of amyloids, namely protein oligomers, are important biological targets as they can be inherently toxic. Understanding the bases of the oligomers toxicity is essential to develop the next generation of biomaterials as well as to understand the nature of some aberrant diseases that are connected to the amyloid formation, including Alzheimer's, Parkinson's and type II diabetes.

An crucial step that defines the biological properties of protein oligomers is the interaction with the cell membrane. This interaction represents the key event in the toxicity of protein oligomers. Understanding the molecular basis of the interaction with the membrane will provide a significant step forward in our understanding of the biology of protein oligomers. Many aspects of this interaction are currently unknown. What makes a prefibrilar oligomer toxic? Why only some protein oligomers are able to penetrate the membrane? How the membrane properties dictate the interplay with protein oligomers?

The present project will provide a novel and innovative platform of experiments and theory to investigate in detail on the structural nature of prefibrilar protein oligomers. The project will shed light in the selective interaction with phospholipid membranes that distinguishes between toxic and non-toxic oligomers. To this aim, the research will combine cutting-edge experiments of nuclear magnetic resonance with advanced molecular computation. Thus, in addition to the specific biological target of tackling the molecular origins of the oligomers toxicity, this research will extend our ability to study complex molecular mechanisms, with a large number of applications ranging from structural biology to synthetic and system biology and to material sciences.

The assembly of proteins and peptides into fibrilar amyloids is a highly promising route to define a new generation of biomaterials. The inherent toxicity of some these aggregates, however, represents a major limiting factor. Understanding the bases of this toxicity, which also plays a role in disorders such as Alzheimer's and Parkinson's, is a major scientific challenge. Several evidences have shown that prefibrilar protein oligomers are the most toxic amyloidogenic species. It is also well established that the interaction with the cell membrane is the key step for oligomers toxicity.

The characterisation of the structures and interactions of the pre-fibrillar oligomers is therefore a top scientific priority for biosciences. This goal currently remains elusive, mainly because of the difficulties of standard approaches of structural investigation to study such transient and dynamical molecular interactions.

I propose to unveil the molecular bases of the cellular toxicity of prefibrilar protein oligomers by characterising and compare the structural properties of toxic and non-toxic HypF-N oligomers in view of their selective interaction with biological membranes. We will achieve this goal by using a combination of solution and solid-state nuclear magnetic resonance (NMR) spectroscopy and advanced tools computational biology. Biophysical and cellular studies will be used to validate our structural results. The collected preliminary data suggest that the research plan is optimally suited for achieving this top scientific goal.

The outcomes of this research impact both the academic sector and the industry as well as both basic and applied sciences. The project will provide a key knowlege for design the next generation of biomaterials based on amyloids. Moreover, the mechanisms of protein oligomers toxicity are important also in the research on amyloid disorders, including Alzheimer's Parkinson's and Diabetes TypeII. This will enhance dramatically our ability to study key molecular processes that are relevant to both academia and industry and extend the applicability of current spectroscopic methods to more complex processes.

INDUSTRIAL BENEFICIARIES: The project is likely to provide a significant impact to industrial research by advancing the use of NMR spectroscopy. Beneficiaries include biotechnological and pharma industry. A key area for applied sciences is the exploitation of new biomaterials based on protein fibrils. In order to develop such biotechnologies, it is necessary understanding and controlling the processes by which protein oligomers elicit cellular toxicity. Additional beneficiaries include those pharmaceutical companies working at the definition of therapeutic approaches to combat amyloid diseases such as Alzheimer's and Parkinson's. These will benefit by the knowledge and data produced in this project. More broadly, the interdisciplinary approaches here proposed will enhance our ability to characterise the mechanisms of heterogeneous biological processes, with key impact on many bio-industrial areas.

SUSTAINABILITY CHALLENGES: The definition of new biomaterials with novel mechanical, chemical and biological properties is a key target for sustainability. By advancing the understanding of the toxicity of some of these oligomers the project will boost this research of new environmentally friendly materials based on protein amyloids.

DISSEMINATION: We will make every effort to ensure that research is disseminated widely to the research community by the Open Access publication in high-impact journals, presentation at international research meetings and the development of new collaborations. Furthermore, protocols and algorithms developed for the analysis of complex NMR data will be made available through the PI website (http://www3.imperial.ac.uk/people/a.de-simon) and the Collaborative Computing project for NMR (CCPN: http://www.ccpn.ac.uk/ccpn).
Where possible, we will also make our findings available to the wider public. Presentations explaining how NMR spectroscopy assists in the drug development, biotechnology and scientific discovery will be made School-oriented presentations and Schools Open Days. The press offices at Imperial will assist in disseminating discoveries via the popular science press and other media formats.

TRAINING: In the proposed research we will employ and develop state-of-the-art methods of NMR spectroscopy to contribute in the wide area of structural biology. This provides an excellent platform to enhance training of PDRAs, PhDs as well as undergraduate students at the interface of biology, chemistry, medicine and chemical engineering.