Publication:

A pyrene-inhibitor fluorescent probe with large stokes shift for the staining of Aβ1–42, α-synuclein, and amylin amyloid fibrils as well as amyloid-containing staphylococcus aureus biofilms

Amyloid fibrils formed by a variety of peptides are biological markers of different human diseases, such as Alzheimer, Parkinson or Type II diabetes, and are structural constituents of bacterial biofilms. Novel fluorescent probes offering improved sensitivity or specificity towards that diversity of amyloid fibrils, or providing alternative spectral windows are needed to improve the detection or the identification of amyloid structures. One potential source for such new probes is offered by molecules known to interact with fibrils, such as the inhibitors of amyloid aggregation found in drug discovery projects. Here, we show the feasibility of the approach by designing, synthesizing and testing several pyrene-based fluorescent derivatives of a previously discovered inhibitor of the aggregation of the Aβ1-42 peptide. All the derivatives tested retain the interaction with the amyloid architecture and allow its staining. The more soluble derivative, compound 1D, stains similarly well amyloid fibrils formed by Aβ1-42, α-synuclein or amylin, provides a sensitivity only slightly lower than that of Thioflavin T, displays a large Stokes shift, allows an efficient excitation in the UV spectral region,and it is not cytotoxic. Compound 1D can also stain amyloid fibrils formed by Staphylococcal peptides present in biofilm matrices and can be used to distinguish, by direct staining,S. aureus biofilms containing amyloid forming phenol soluble modulins from those lacking them.