Nanoscale metallomics and mineralization: advanced spectro-microscopy determination of the role of iron and calcium in Alzheimer's disease

Lead Research Organisation: University of Warwick
Department Name: Sch of Engineering

Abstract

The most common form of dementia is Alzheimer's disease, a neurodegenerative disorder that reportedly affects 30 million people worldwide, yet for which there is no cure and only limited opportunities for accurate diagnosis and treatment. The disease is characterised by pathological hallmarks in the brain including dense amyloid protein aggregates (plaques) that are deposited outside cells in the grey matter of the brain, together with significant damage internally in neurons due to 'tangles' of abnormal tau protein. These plaques and tangles are understood to contribute to the death of neurons and the progressive degeneration of the brain. Exactly how this degeneration is mediated by these protein deposits is not yet properly understood. However, oxidative stress damage to neurons, catalysed by highly reactive chemical species known as free radicals, is understood to play a significant role. In addition, substantial evidence now suggests that the dysregulation of iron resulting in a harmful excess of reactive (ferrous) iron in the brain, is a contributing factor in the disease, and may be implicated in the processes leading to oxidative stress.

Interactions between aberrant protein deposits and iron, as well as other metals, are common features of neurodegenerative disorders. In Alzheimer's disease, metal-protein interactions are hypothesized to contribute to the formation of deposits containing reactive (harmful) iron observed post-mortem in diseased brain tissue. In addition, unusual calcium bio-mineralisation has been observed within areas of aberrant protein deposition suggesting that calcium could also play a significant role in the disease. Identifying these mineral products is an important first step in describing this aspect of Alzheimer's disease. However in order to make progress in diagnosing and treating the disease, it is necessary to understand how the metal-protein interactions contribute to the disease process at a level facilitating therapeutic intervention, and the extent to which resulting iron and calcium mineralization in the protein deposits can serve as an early-stage marker of the disease.

We aim to explore the chemical and mineral state of iron and calcium in Alzheimer's disease brain tissue using sensitive and specific analytical methods, as well performing experiments to investigate how metal-protein interactions can lead to the initiation and evolution (both chemical and structural) of the protein deposits. Further, we will assess how the metal-protein aggregates formed in human brain tissue, as well as those created artificially, respond to treatments with the metal chelating agents that are currently being developed as potential drug therapies for Alzheimer's and other neurodegenerative conditions.

To ensure the success of this project we have assembled a unique interdisciplinary research team, with a strong international track record, to build upon our successful preliminary work in this area, applying a combination of advanced synchrotron x-ray microscopy and mass spectrometry techniques to probe nanoscale variations in the bio-inorganic chemistry occurring in Alzheimer's tissue. An important aspect of the project is that in all cases we will support our evaluation using these specialist techniques, with conventional imaging and histology. From this we will build a comprehensive description of this fundamental process in Alzheimer's disease, addressing key outstanding questions about the metal-protein interactions and how they may be modified. The parallels between aberrant protein deposition and altered handling of iron and other metals in related disorders, will allow the approach developed in this project to be readily translated, enabling equivalent impact for other forms of neurodegenerative disease. With clinical advances in chelation therapy and improved scope to track brain iron status non-invasively by clinical MRI, this project is not just timely but also urgent.

Publications

10 25 50
 
Description The methodologies we have developed in this project represent a significant advance in the application of synchrotron x-ray approaches to analyze human tissues. In particular, we have used the exceptional chemical and magnetic sensitivity of x-ray techniques to map the biochemistry of brain tissue on sub-cellular length scales, enabling the detection of nanoscale deposits of copper and iron in differing forms. These nanoscale deposits were found within amyloid plaques, a hallmark pathological lesion of Alzheimer's disease. We relate them to links between disrupted metal homeostasis, the development of Alzheimer's disease, and the formation of pathological amyloid lesions. Concurrently, we developed new methods that use x-ray chemical spectroscopic signatures to map the spatial distribution of important biological compounds of relevance to neurodegenerative diseases. In addition to studying ex vivo tissue, we also performed experiments on in vitro samples, and established a link between amyloid aggregation and the chemical reduction of iron biominerals within the iron storage protein ferritin. Together, these experiments reveal a new level of complexity in the role of metals in neurodegenerative diseases and add new concepts to our current understanding of human neurobiology. Further to this, the project unveiled an unexplored fundamental step in the development of Alzheimer's and related diseases, and opened up new research avenues for the study of disease aetiology, treatment, and diagnosis. In addition, our findings offer a new explanation for toxicity associated with amyloid structures within Alzheimer's disease tissues, and a "metal-dependent" caveat to the amyloid hypothesis cascade.
Exploitation Route Through this project, we were able to engage with the global academic and clinical research communities, and successfully demonstrated how specialist techniques such as x-ray spectromicroscopy and FTICR mass spectrometry can be applied to new research areas crossing biochemistry and medical themes. The results of the project have opened up new research avenues for the study of the aetiology, treatment, and diagnosis of neurodegenerative and other diseases where nanoscale biochemistry plays a significant role. We are already observing evidence of the impact of our work with our project publications receiving rapid and diverse recognition across the global academic and medical community. Further collaborative projects that build on our successes here are currently in development.
Sectors Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology

 
Description Input into Diamond II Science Case
Geographic Reach Multiple continents/international 
Policy Influence Type Participation in a national consultation
 
Description Roundtable on air pollution and dementia hosted by the Alzheimer's Society
Geographic Reach National 
Policy Influence Type Participation in a advisory committee
URL https://www.alzheimers.org.uk/for-researchers/report-on-link-between-air-pollution-and-dementia
 
Description Diamond Light Source Programme Access - Long Term Research
Amount £0 (GBP)
Organisation Diamond Light Source 
Sector Private
Country United Kingdom
Start 04/2017 
End 03/2019
 
Description UKRI COVID-19 Grant Extension Allocation
Amount £104,408 (GBP)
Organisation United Kingdom Research and Innovation 
Sector Public
Country United Kingdom
Start 01/2021 
End 09/2021
 
Title Neuromelanin imaging 
Description Identification and use of feature in soft x-ray spectrum to image neuromelanin, demonstrated in human brain tissue where the neuromelanin was identified independently of the surrounding tissue. 
Type Of Material Technology assay or reagent 
Year Produced 2020 
Provided To Others? Yes  
Impact 1. Supported progression of researcher into funded postdoctoral position. 2. Work featured in forthcoming DLS Annual Report to showcase work at the beamline where the method was developed. 
URL https://onlinelibrary.wiley.com/doi/full/10.1002/anie.202000239
 
Title XMCD technique developed at Diamond beamline I08 
Description We successfully demonstrated the x-ray magnetic circular diochroism method for use in spectromicroscopy, for the first time at beamline I08 at Diamond Light Source. This method enables the magnetic character of nanoscale regions to be assessed within sample. Using this method we were able to determine the magnetic state of some iron biomineral inclusions in Alzheimer's plaque material extracted from human brain tissue. We have added this new data to paper currently under revision for the journal Nanoscale. 
Type Of Material Technology assay or reagent 
Year Produced 2018 
Provided To Others? Yes  
Impact Broader impacts will be generated in the longer term. 
 
Description AlzForum debate 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Contributed invited response to an article on the USA AlzForum site: "Does High Iron Push a Person With Pathology Into Dementia?"
Year(s) Of Engagement Activity 2019
URL https://www.alzforum.org/news/research-news/does-high-iron-push-person-pathology-dementia
 
Description Frederik Leremyte presentation at 66th Conference on Mass Spectrometry and Allied Topics 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Presentation delivered at the 66th ASMS Conference on Mass Spectrometry and Allied Topics. The conference remains at the forefront of mass spectrometry and attracts a wide range of delegates from academic and R&D areas.
Year(s) Of Engagement Activity 2018
URL https://www.asms.org/conferences/annual-conference/annual-conference-homepage
 
Description James Everett invited talk at Diamond-II Workshop: Imaging 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Other audiences
Results and Impact The aims of the workshop were to introduce Diamond-II, to discuss its potential benefits for the existing facilities, and to develop the science case for the machine upgrade. James's talk presented our work on x-ray spectromicroscopy and discussed how Diamon-II would impact on this.
Year(s) Of Engagement Activity 2018
URL https://www.diamond.ac.uk/Home/Events/2018/DiamondIIBioIma.html
 
Description James Everett presentation at UKSR50 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact A conference to celebrate the achievements and explore the future of the light sources (Synchrotrons and FELs) and their applications in the coming decades.
Year(s) Of Engagement Activity 2018
URL http://www.uksr50.org/
 
Description James Everett talk at XRM2018 conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Oral presentation by team member at the International Conference on X-ray Microscopy (XRM2018).

XRM2018 brought together experts in the development and use of X-ray microscopes. This conference addressed the most recent advances in X-ray microscopy technology and applications through a program of talks, posters, and social interaction.
Year(s) Of Engagement Activity 2018
URL http://xrm2018.com/
 
Description STEM for Britain 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Selected presentation by JB of selected work arising from this project at the 2020 STEM for Britain event, showcasing the work to Members of Parliament.
Year(s) Of Engagement Activity 2020
URL https://stemforbritain.org.uk/