A Novel Cu(II)-Binding Peptide Identified by Phage Display Inhibits Cu2+-Mediated Aβ Aggregation

Abstract

Copper (Cu) has been implicated in the progression of Alzheimer’s disease (AD), and aggregation of Cu and amyloid β peptide (Aβ) are considered key pathological features of AD. Metal chelators are considered to be potential therapeutic agents for AD because of their capacity to reduce metal ion-induced Aβ aggregation through the regulation of metal ion distribution. Here, we used phage display technology to screen, synthesize, and evaluate a novel Cu(II)-binding peptide that specifically blocked Cu-triggered Aβ aggregation. The Cu(II)-binding peptide (S-A-Q-I-A-P-H, PCu) identified from the phage display heptapeptide library was used to explore the mechanism of PCu inhibition of Cu2+-mediated Aβ aggregation and Aβ production. In vitro experiments revealed that PCu directly inhibited Cu2+-mediated Aβ aggregation and regulated copper levels to reduce biological toxicity. Furthermore, PCu reduced the production of Aβ by inhibiting Cu2+-induced BACE1 expression and improving Cu(II)-mediated cell oxidative damage. Cell culture experiments further demonstrated that PCu had relatively low toxicity. This Cu(II)-binding peptide that we have identified using phage display technology provides a potential therapeutic approach to prevent or treat AD.

Phage display derived peptides for Alzheimer's disease therapy and diagnosis

“…Thioflavin T (ThT) fluorescence assay was used to monitor the process of peptide inhibition of amyloid fibrillation in real time, because the fluorescence intensity of ThT positively correlates with the content of the misfolded protein β-sheet structure 56 . Similarly, the morphological changes of phage display peptides affecting the aggregation of Aβ peptide or tau protein are usually observed by transmission electron microscopy (TEM) and atomic force microscopy (AFM) 57 , 58 . Furthermore, CD spectra 59 and two-dimensional nuclear magnetic resonance (2D-NMR) 60 are also complemented with fixed point and in vitro detection.…”

“…At the cellular level, it mainly evaluates the biocompatibility of phage-derived peptides, whether it can penetrate cell membranes, and recuse toxic factors such as Aβ/tau oligomers and fibers induced cell cytotoxicity 57 , 58 . The application of functional peptides in animal models of AD represents a more realistic therapeutic efficiency under physiological conditions.…”

“…A very recent paper using the similar strategy reported a novel Cu-binding peptide using the phage display technique to screen for a potential inhibitor for Cu(II)-induced Aβ peptide aggregation 58 . A heptapeptide sequence of SAQIAPH (PCu) as a potential Cu(II)-binding peptide was identified, which could remarkably inhibit Cu(II)-induced Aβ aggregation and mediates the cellular toxicity.…”

Aspartic Acid-Modified Phospholipids Regulate Cell Response and Rescue Memory Deficits in APP/PS1 Transgenic Mice

“…Therefore, the effects of chiral liposomes and Aβ 40 on the stability of MMP were investigated by JC-1 fluorescent staining. JC-1 is an ideal fluorescent probe for MMP detection in cell biology. − JC-1 accumulates to form J-aggregates in mitochondria at the normal MMP level and emits red fluorescence (with the maximum emission at 590 nm). Conversely, in nonhealthy or apoptotic cells, low-levels of mitochondrial MMP could not attract enough JC-1 molecules, and thus JC-1 cannot form aggregates and maintains its monomer state, which emits green fluorescence with the maximum emission at 527 nm.…”

A Novel polysaccharide DSPP-1 from Durian seed: structure characterization and its neuroprotective effects against Alzheimer's disease in a transgenic Caenorhabditis elegans model

“…Aβ 1−40 and Aβ 1−42 are the two most abundant forms of Aβ in the brain (Yu et al, 2021). Moreover, Aβ 1−42 readily forms aggregates and has higher neurotoxicity than Aβ 1−40 (Zhang et al, 2021). The evidence indicates that Aβ oligomers perturb the integrity of membrane lipid bilayers, increase ion permeability, cause calcium in ux and consequently affect synaptic transmission and neuronal viability (Tao et al, 2020).…”