From bio-inspired molecules to Alzheimer's Disease prevention

Natural polyphenols are very important substances found in various natural sources (e.g. food and wood). Their antioxidant, anti-ageing, anti-inflammatory and cardioprotective activities are well known. In recent papers the ability of some natural polycyclic polyphenols, such as resveratrol, curcumin, flavonoids, and so on, to inhibit amyloid aggregation was reported,1 suggesting a potential utility of these compounds for the prevention of neurodegenerative disorders, such as Alzheimer's Disease (AD). Thus these molecules may be envisioned as very useful nutraceutical ingredients to prevent several age-related disorders. The project focusses on the synthesis of new polyphenolic compounds from a series of simple (only one benzene ring) phenolic compounds that can be extracted from natural sources or waste. The principal aim of the project is to valorize these starting materials. They will be used as such for the combinatorial synthesis of the final products, or converted into "second generation" building blocks, including amines. The synthesis of "second generation" building blocks will exploit operationally simple and sustainable synthetic steps that will adhere as much as possible to the "ideal synthesis" imperatives (step and atom economy, high rate of complexity increase). Then, all first generation or second generation building blocks will be assembled, in a combinatorial manner, using "smart" synthetic methodologies, such as multicomponent reactions or "click" reactions. Finally, further rigidification (guided by computational modelling) will be attained through post-condensation cyclization steps, producing heterocyclic scaffolds. In this way, a quite diverse collection of complex polyphenolic compounds, containing two or three of the starting fragments as well as other non-phenolic appendages, will be produced during the project. After the synthesis of the new molecules, the structure modification of the complexes bio-inspired molecules/A? peptides will be monitored versus time, using biophysical characterization. The experiments will be performed by keeping constant the total concentration of A? peptides with different amounts of each bio-inspired molecule. The resulting samples will be analyzed by: 1) circular dichroism, a spectroscopic technique able to evaluate the changes in the secondary structure with time; 2) multidimensional NMR spectroscopy to depict the interactions between A? peptides and the selected compounds at atomic level 3) ThT and ANS fluorescence to evaluate the changes in beta-sheets content and the changes in the amount of hydrophobic groups on the external surface of the amyloid structure; 4) measurements of sample turbidity (absorbance at 405 nm) to follow the polymerization kinetics, accompanied by 1D NMR experiments to monitor the intensity of selected signals over time; 5) Diffusion- Ordered Spectroscopy (DOSY) NMR experiments to measure translational properties of the molecules in solution and detect aggregation phenomena. 6) The time evolution of the ultrastructure morphology of the peptide aggregates in the presence of new synthesized molecules will be approached by transmission electron microscopy. The atomic details of the complexes A? peptides/selected bio-inspired molecules (SBIM) will be investigated by multidimensional NMR. All the acquired data will be used to propose a structural model of the complexes A? peptides/SBIM by experimental driven docking techniques. The neuroprotective efficacy of polyphenols will be investigated at multiple levels in vivo in APP/PS1 mice on learning and memory, synaptic structure, amyloid pathology and neuroinflammation. These Click to buy NOW! P D F - X C h a n g e P r o d u c t w w w . t r a c k e r - s o f t w a r e . c o m Click to buy NOW! P D F - X C h a n g e P r o d u c t w w w . t r a c k e r - s o f t w a r e . c o m neuropathological hallmarks will be investigated at the age of 12-13 months, age at which they are all detectable. The preventive potential of the polyphenols will be also investigated starting the treatment at a pre-symptomatic age of 5 months. Behavioural evaluation of mice will be carried to detect mouse memory deficits in APP/PS1 mice. The potential of polyphenols to recover alterations of synaptic structure, strongly affected in both humans and our APP/PS1 mice, will be carried out through histological or biochemical procedures. Amyloid pathology will be investigated by monitoring plaque numbers and area, levels of total Ab and, particularly important, of Ab oligomers (AbOs). By taking advantage of the newly developed acute mouse model in partner 2's lab, it will be investigated whether polyphenols can specifically counteract the action of AbOs. Thus, to reach our goal, it will be investigated whether pre- incubation of AbOs with polyphenols will abolish their detrimental activities on both memory and neuroinflammation.