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Ultrafast photonics for the detection and recognition of toxic spine-structures of amyloid aggregates linked to neurodegenerative disease

Periodic Reporting for period 1 - UPRECON (Ultrafast photonics for the detection and recognition of toxic spine-structures of amyloid aggregates linked to neurodegenerative disease)

Reporting period: 2018-08-01 to 2020-07-31

Neurodegeneration becomes one of the most commonly diagnosed dysfunctions with no certain cure or successful therapy. Projections indicate that, by 2050 over 150M people will be suffering. Neurodegenerative diseases have a greater chance of affecting individuals with the age of 65 years or older. The final product which is a fibrillar structure of the protein is often found in the form of plaques in brains of persons having Parkinson’s, Alzheimer’s, frontotemporal dementia (FTD) and many other neurological diseases.
Disease development is related to molecular machinery where mistakes in protein functioning lead to misfolding and aggregation. The consensus is that neurodegeneration starts years before clinical symptoms occur when smaller oligomers start to aggregate. It is accepted that formation of the specific oligomer structures may cause toxicity in terms of neurodegeneration progression.
Photonics technology has the accurate sensitivity for early stage amyloid aggregates detection and light can be used to penetrate non-invasively the tissue. That can be used for diagnostics for patients with mild cognitive problems.

The UPRECON project was relevant to human medicine for the diagnosis and successful treatment of neurodegenerative diseases in an increasingly aging population worldwide and particularly in developed countries. Finding non-invasive methods for detection of early stage neurodegeneration before clinical symptoms occur is critical for longevity in good health. The idea of the project was to examine laser-based methods that could be developed as diagnostic tools that will not be harmful to patients since the applied light will be in the optically transparent window for living organisms.

The overall objectives were focused on detecting early stage amyloidic structures. The key questions were how to develop diagnostic tools capable of detecting structures prone for neurodegeneration and possibly how to differentiate the toxic species by using photonic methods.
Photonic methods were evaluated in terms of detection sensitivity to the amyloid oligomers and their structures. The aim was to resolve the toxic oligomer specious and structural architectures (so called steric zippers) in similar dilutions to those present in cerebrospinal fluids (CSF) of patients with cognitive diseases. Among examined techniques amplified spontaneous emission (ASE) supported with time-resolved fluorescence (TRF) revealed great potential in detecting early stage aggregates. Applying femtosecond ultrafast pulses it was possible to induce ASE effect in one- and two-photon excited process. Especially the two-photon excited ASE was promising in terms of the development of non-invasive diagnostic tool.
In contrast to fluorescence, ASE appeared only when intensity of the exciting light exceeds a certain energy threshold which was dictated by the interplay between the energy gain due to stimulated emission and energy losses. The latter was linked to the microscopic structure of the medium. In the particular case of protein aggregation the energy losses were increasing with the yield of light scattering. That fact made the ASE a parameter which was directly related to the aggregated form of the protein. Therefore, ASE provided additional bioanalytical information that complemented traditional fluorescence methodology.
Time-resolved fluorescence (TRF) was found to be sensitive for weakly emissive fluorophores interacting with amyloid oligomers. It was possible because single photon events could have been detected and their time of arrival (fluorescence lifetime) was correlated to the laser pulse which was used for excitation of the sample. The results showed that time-resolved fluorescence had better recognition rate for oligomers than standard fluorescence. Based on the results obtained in the project, access to shorter lived pathologically relevant species of in vivo aggregates was achieved. ASE and TRF techniques were further development for the diagnostics of the early stage amyloid oligomers. For improving the public understanding of scientific problems and challenges related to the neurodegeneration and potential solution to the diseases developments the PI was actively involved in education and media programs. The report summarizing the situation on neurodegeneration worldwide was prepared.
In the UPRECON project photonic technology was developed to detect early stage amyloid aggregates named oligomers that are associated with neurodegeneration. Using laser-based techniques in the project the detection was explored in high dilutions, similar to those present in cerebrospinal fluid (CSF) collected from patient's with Alzheimer disease, and in terms of differentiation of the strand organization of the Beta-sheets in the aggregates which can be related with oligomers toxicity.
The project aimed to explore the intrinsic optical properties of amyloid fibrils and use that knowledge for improving the detection sensitivity for amyloids in CSF. The broader technical scope beyond the conventional methods was shown and implemented to study protein and peptide aggregation in CSF. The collected data in the UPRECON supported further development of the diagnostic tool for amyloid oligomers detection.
The knowledge obtained during the UPRECON project paved the ground for establishing a research team at the University of Warsaw, Physics Faculty in the field related to neurodegeneration which is of high societal importance and is one of the EU health priorities. The team is member of the consortium in the joint programme – neurodegenerative disease research (JPND) project. The multinational project focus is on the detection of early symptoms of neurodegeneration and propose personalized therapies for Parkison’s disease.
The project matches with the UPRECON impact which was aiming for development of the photonic detection tool for patients with mild cognitive symptoms. The general concept about the early detection of neurodegenerative symptoms methodology based on light remains valid and meets the expectation of society for sustaining long life vitality in the aging population. UPRECON results fits the prevention strategy approach which is the most promising for the neurodegeneration because it will not require expensive pharmacologic therapies in which the drugs must be administered for long periods and guarantee only inhibition of disease progression.
The impact of UPRECON project is timely in relation to societal needs for the diagnosis of neurodegenerative diseases before clinical symptoms occur.