LUMINOL BASED BRET PHOTOOXIDATION OF AMYLOID β

Alzheimer`s disease (AD) is a cureless and age related neurodegenerative disease that affects approximately 24 million people worldwide. The disease is characterized by degeneration of brain cells over time, resulting in the loss of cognitive functions, primarily memory, judgment and reasoning, movement coordination and pattern recognition. In advanced stages of the disease, all memory and mental functioning may be lost. Amyloid beta (Aβ) is a short peptide (40 to 43 amino acids) that is formed by cleavage of the amyloid precursor protein (APP). The accumulation of Aβ deposits in the brain is considered to be the major cause of AD pathogenesis, which is currently the subject of intense study. At sufficiently high concentration, soluble Aβ monomers gradually undergo dramatic conformation changes to form soluble aggregates that are characterized by β-sheet-rich tertiary structure and eventually convert to insoluble fibrils. We have shown thatolyaromatic photosensitizers, such as chlorin e6 (Ce6), are potent inhibitors of Ab aggregation. Ce6 binds Aβ and inhibits its aggregation under darkness conditions. Remarkably, we have shown that the anti-amyloidogenic of Ce6 is significantly enhanced upon irradiation with visible light (Leshem,G. et al, unpublished).
Since deep tissue irritation of Ce6 in brain is not feasible, we propose in this study to use bioluminescence resonance energy transfer (BRET) using luminol-Horseradish Peroxidase (HRP)-H₂O₂ system as a source for activation of Ce6.