Selective targeting of primary and secondary nucleation pathways in Aβ42 aggregation using a rational antibody scanning method

Abstract

A rational approach enables the almost complete suppression of nucleation events in Aβ42 aggregation using designed antibodies.

Differential Modulation of the Aggregation of N‐Terminal Truncated Aβ using Cucurbiturils

“…To gain a better understanding about the mechanisms of supramolecular inhibition, we referred to the chemical kinetics analysis . Generally speaking, nuclei were formed by monomers through primary nucleation, a rate‐limiting step in fibrillation.…”

“…Short protofibrils further grew into long mature fibrils through elongation, which exhibits either a linear (nonsaturated) or sub‐linear (saturated) dependence on the monomer concentration . In addition, surface catalysed secondary nucleation also played a role by providing an alternative way for generating new seeds in replace of primary nucleation and thus dramatically accelerating the aggregation process …”

“…As a further validation, we explored other possible inhibition mechanisms besides fibril‐end binding to see whether they can explain the data. Here, three additional mechanisms, inhibition of elongation, primary nucleation and secondary nucleation, were considered, respectively . In the first two cases, it was assumed that CB[7]/CB[8] could bind with Aβ monomers, which in turn decreased the effective monomer concentration and thus slowed down the fibril elongation/primary nucleation processes.…”

“…Firstly,w ee xamined the binding of Ab [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and Ab 4-16 with CB [7] and CB [8] by isothermal titration calorimetry (ITC). Our results showed that Ab 4-16 bound with CB[7] with K a ¼ 1:13 AE 0:14 ðÞ Â 10 6 M À1 ; N ¼ 0:92 AE 0:05 ( Figure 2), whereas Ab 1-16 showed much weaker binding affinity (around 1  10 4 M À1 ,F igure S2 A, Supporting Information).U sing at wosequential-binding-sites model, we calculated that Ab 4-16 boundw ith CB [8] with K a ¼ð5:46 AE 0:62Þ Â 10 10 M À2 (Figure 2B).…”

“…Our results showed that Ab 4-16 bound with CB[7] with K a ¼ 1:13 AE 0:14 ðÞ Â 10 6 M À1 ; N ¼ 0:92 AE 0:05 ( Figure 2), whereas Ab 1-16 showed much weaker binding affinity (around 1  10 4 M À1 ,F igure S2 A, Supporting Information).U sing at wosequential-binding-sites model, we calculated that Ab 4-16 boundw ith CB [8] with K a ¼ð5:46 AE 0:62Þ Â 10 10 M À2 (Figure 2B). In contrast, the ITC data for Ab [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] with CB [8] could not be distinguished from the background noise (Figure S2 B,C). As as ummary,C B [7] and CB [8] could bind with Ab 4-16 but not Ab [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] under neutralc onditions.…”