The misfolding and aggregation of amyloidogenic proteins such as amyloid-β (Aβ1–42) represent key pathogenic mechanisms in neurodegenerative diseases such as Alzheimer’s disease. Soluble oligomers are considered early and pathological relevant intermediates in this process, but they remain difficult to detect and distinguish from other amyloidogenic species, such as human islet amyloid polypeptide (hIAPP).
Fluorescent probes provide a tool to monitor aggregation species in vitro. However, most currently available molecules lack the selectivity to recognize oligomeric species and, more importantly, to differentiate between distinct amyloidogenic proteins.
In this study, we present peptide– rotor-based fluorophore conjugates as a novel approach for the detection of soluble oligomers and as an effective strategy to enhance the specificity and functionality of molecular probes. Various conjugation strategies were applied for the late-stage diversification of a BODIPY-based fluorophore scaffold and were systematically compared. The resulting conjugates exhibited significantly improved sensitivity towards oligomers compared to taBODIPY, [1,2] and enabled discrimination between oligomeric species derived from the highly homologous peptides Aβ1–42 and hIAPP.
We demonstrate the effect and pharmacological relevance of the peptide sequences and their conjugated probes. Furthermore, the results of the conjugated probes were validated using an optimized protocol under controlled Aβ1–42 aggregation conditions and the probes were successfully applied in an assay for the detection of early species of Aβ1–42. These findings highlight the potential of peptide–fluorophore conjugates as a modular platform for the targeted development of oligomer-specific detection tools in vitro.