Dual Inhibitors of Amyloid-β and Tau Aggregation with Amyloid-β Disaggregating Properties: Extended In Cellulo, In Silico, and Kinetic Studies of Multifunctional Anti-Alzheimer’s Agents

Abstract

In Alzheimer’s disease, neurons slowly degenerate due to the accumulation of misfolded amyloid β and tau proteins. In our research, we performed extended studies directed at amyloid β and tau aggregation inhibition using in cellulo ( Escherichia coli model of protein aggregation), in silico , and in vitro kinetic studies. We tested our library of 1-benzylamino-2-hydroxyalkyl multifunctional anti-Alzheimer’s agents and identified very potent dual aggregation inhibitors. Among the tested derivatives, we selected compound 18 , which exhibited a unique profile of biological activity. This compound was the most potent and balanced dual aggregation inhibitor (Aβ 42 inhibition (inh.) 80.0%, tau inh. 68.3% in 10 μM), with previously reported in vitro inhibitory activity against h BuChE, h BACE1, and Aβ ( h BuChE IC 50 = 5.74 μM; h BACE1 IC 50 = 41.6 μM; Aβ aggregation (aggr.) inh. IC 50 = 3.09 μM). In docking studies for both proteins, we tried to explain the different structural requirements for the inhibition of Aβ vs tau. Moreover, docking and kinetic studies showed that compound 18 could inhibit the amyloid aggregation process at several steps and also displayed disaggregating properties. These results may help to design the next generations of dual or selective aggregation inhibitors.

Amyloid Cross-Seeding: Mechanism, Implication, and Inhibition

“…It was also observed that injecting α-syn monomers exogenously in mice promoted faster aggregation of IAPP, whereas IAPP amyloid formation was reduced in mice lacking the gene encoding α-syn [ 191 ], further implying the cross-seeding interaction between α-syn and hIAPP. Recently, it was reported that the octapeptide TKEQVTNV from α-syn can cross-seed with hIAPP monomers and facilitate hIAPP fibrillation [ 192 ]. Moreover, the cross-seeding between the octapeptide from α-syn and hIAPP could increase cell viability and reduce cell apoptosis by reducing hIAPP induced cytotoxicity [ 192 ], suggesting a broader impact of cross-seeding.…”

“…Recently, it was reported that the octapeptide TKEQVTNV from α-syn can cross-seed with hIAPP monomers and facilitate hIAPP fibrillation [ 192 ]. Moreover, the cross-seeding between the octapeptide from α-syn and hIAPP could increase cell viability and reduce cell apoptosis by reducing hIAPP induced cytotoxicity [ 192 ], suggesting a broader impact of cross-seeding.…”

“…Several dual inhibitors against Aβ and tau have been reported. Recently, an extended in cellulo, in silico, and kinetic study was performed to test the inhibition efficiency of 1-benzylamino-2-hydroxyalkyl derivatives to identify a potent inhibitor against Aβ and tau [ 192 ]. It was observed that one of the compounds could inhibit 80% Aβ42 aggregation and 68.3% tau aggregation.…”

“…The data from the docking studies also suggested the significant impact of chirality on the antiaggregation property of the inhibitor. The researchers suggested that S-isomers are favorable for Aβ and R-isomers for tau [ 192 ]. A series of peptide-based inhibitors have been designed that act as dual inhibitors against Aβ and tau [ 168 ].…”

A unifiedin vitrotoin vivofluorescence lifetime screening platform yields amyloid β aggregation inhibitors

“…After years of failing to find a suitable therapeutic drug against AD, researchers are still using historically established assays, such as MTT, Thioflavin S staining or fluorescence intensity based aggregate counting to validate their in vitro or in silico hits. 53, 54, 55 The unified fluorescence lifetime screening system described in this work overcomes this historical burden and bridges the gap that intrinsically exists between in vitro and in vivo approaches, permitting results from a medium-throughput microfluidic screen to be directly compared to physiologically relevant cellular and whole organism analysis.…”