Design and Engineering of Amyloid Aggregation‐Prone Fragments and Their Antimicrobial Conjugates with Multi‐Target Functionality

Abstract

AbstractAmyloid aggregation and microbial infection are considered major risk factors for neurodegeneration and neuroinflammation in protein misfolding diseases (PMDs), including Alzheimer's disease (AD) and Type 2 diabetes (T2D). However, current amyloid inhibitors are mostly limited to single‐target prevention strategies against specific amyloid proteins or pathogenic microbes, leading to no success for clinical cures of PMDs. Here, a step‐by‐step strategy to design new, multi‐target amyloid aggregation‐prone fragments (APFs) and their APFs antimicrobial agent conjugates is proposed, capable of achieving the stepwise improved multifunctionality of amyloid inhibition, antimicrobial activity, and amyloid imaging. The two APFs of KLVFF from Aβ (associated with AD) and FGAIL from hIAPP (associated with T2D) with β‐structure‐forming property are selected and used as building block to construct a hybrid KLVFFGAIL peptide (K9) and a K9‐AMC (7‐amino‐4‐methylcoumarin) fluorescence conjugate, both of which have demonstrated the improved, multiple‐target, sequence‐independent functions to inhibit the aggregation of both Aβ and hIAPP, reduce both Aβ‐ and hIAPP‐induced cell toxicity, prevent different microbial growth, and introduce fluorescence images for amyloid fibrils. The sequence‐independent amyloid inhibition function of K9 and K9‐AMC mainly stems from their cross‐interactions with amyloid proteins via β‐structure and aromatic interactions. This work provides a proof‐of‐concept example to not only explore a new family of APFs as antimicrobial and anti‐amyloid drugs for the therapeutic potential of PMDs, but also better understand the pathological links between protein aggregation and microbial infection in PMDs along the gut–brain axis.