Small Molecule Fluorescent Probes for the Detection of Amyloid Self-Assembly In Vitro and In Vivo

Carlos      W. Bertoncini; M.      Soledad Celej

doi:10.2174/138920311795860151

Abstract

The misfolding and aggregation of amyloidogenic polypeptides are characteristics of many neurodegenerative syndromes including Alzheimers and Parkinsons disease. There is a major interest in the availability of amyloid-specific probes that exhibit fluorescence properties for its use as reporters of protein aggregation in spectroscopy and microscopy methodologies. In this review we intend to provide an overview of novel fluorescence-based probes and procedures applied for addressing fundamental aspects of amyloid self-assembly in vitro and in vivo. We highlight the utilization in vitro of several small-molecule fluorescent probes as extrinsic and site-specific reporters of amyloid formation, including single-molecule determinations. Detection of amyloid self-assembly employing compounds such as JC-1, DCVJ, ANS derivatives and luminescent conjugated polymers, as well as site-specific probes such as pyrene and ESIPT is discussed. We further review novel fluorescent probes developed for the non-invasive optical imaging of protein aggregates in vivo, including BTA-1, Methoxy-X04, NIAD-4 and CRANAD-2. Availability of increasingly versatile amyloid-specific fluorescent probes is having a very positive impact in the drug discovery and diagnostics fields.

Keywords: Amyloid fibril, amyloid oligomer, amyloid probe, amyloid staining, fluorescence imaging, fluorescence microscopy, fluorescence spectroscopy, single-molecule fluorescence, amyloidogenic polypeptides, protein aggregation, Protein Misfolding, luminescent