Reverse engineering synthetic antiviral amyloids

Human amyloids have been shown to interact with viruses and interfere with viral replication. Based on this observation, we employed a synthetic biology approach in which we engineered virus-specific amyloids against influenza A and Zika proteins. Each amyloid shares a homologous aggregation-prone fragment with a specific viral target protein. For influenza we demonstrate that a designer amyloid against PB2 accumulates in influenza A-infected tissue in vivo. Moreover, this amyloid acts specifically against influenza A and its common PB2 polymorphisms, but not influenza B, which lacks the homologous fragment. Our model amyloid demonstrates that the sequence specificity of amyloid interactions has the capacity to tune amyloid-virus interactions while allowing for the flexibility to maintain activity on evolutionary diverging variants. Some human amyloid proteins have been shown to interact with viral proteins, suggesting that they may have potential as therapeutic agents. Here the authors design synthetic amyloids specific for influenza A and Zika virus proteins, respectively, and show that they can inhibit viral replication

Aggregating sequences that occur in many proteins constitute weak spots of bacterial proteostasis

Aggregation is a sequence-specific process, nucleated by short aggregation-prone regions (APRs) that can be exploited to induce aggregation of proteins containing the same APR. Here, we find that most APRs are unique within a proteome, but that a small minority of APRs occur in many proteins. When aggregation is nucleated in bacteria by such frequently occurring APRs, it leads to massive and lethal inclusion body formation containing a large number of proteins. Buildup of bacterial resistance against these peptides is slow. In addition, the approach is effective against drug-resistant clinical isolates of Escherichiacoli and Acinetobacterbaumannii, reducing bacterial load in a murine bladder infection model. Our results indicate that redundant APRs are weak points of bacterial protein homeostasis and that targeting these may be an attractive antibacterial strategy

Retro-inversal of intracellular selected ?-amyloid-interacting peptides: implications for a novel Alzheimer's disease treatment

The aggregation of ?-amyloid (A?) into toxic oligomers is a hallmark of Alzheimer's disease pathology. Here we present a novel approach for the development of peptides capable of preventing amyloid aggregation based upon the previous selection of natural all-l peptides that bind A?1-42. Using an intracellular selection system, successful library members were further screened via competition selection to identify the most effective peptides capable of reducing amyloid levels. To circumvent potential issues arising from stability and protease action for these structures, we have replaced all l residues with d residues and inverted the sequence. These retro-inverso (RI) peptide analogues therefore encompass reversed sequences that maintain the overall topological order of the native peptides. Our results demonstrate that efficacy in blocking and reversing amyloid formation is maintained while introducing desirable properties to the peptides. Thioflavin-T assays, circular dichroism, and oblique angle fluorescence microscopy collectively indicate that RI peptides can reduce amyloid load, while 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays demonstrate modest reductions in cell toxicity. These conclusions are reinforced using Drosophila melanogaster studies to monitor pupal hatching rates and fly locomotor activity in the presence of RI peptides delivered via RI-trans-activating transcriptional activator peptide fusions. We demonstrate that the RI-protein fragment complementation assay approach can be used as a generalized method for deriving A?-interacting peptides. This approach has subsequently led to several peptide candidates being further explored as potential treatments for Alzheimer's disease