Identification of druggable targets against Vibrio pathogens

Toxigenic Vibrio species cause disease in farmed shrimp, costing tens of billions of dollars of damage to the global shrimp industry. Building on previous work that contributed to understanding the causative agent, we now propose to develop neutralizing toxin-binders for use in rearing and farming food shrimp. Peptide based inhibitors have been successfully tested on pathogenic shrimp viruses, but not yet implemented to target bacterial toxins. Peptides that are efficacious in preventing shrimp disease will be of significant global economic value as they are cheap to produce and can be conveniently deployed in yeast, which are already a component of shrimp feed. The project objectives are to determine whether peptides identified by a combination of large-scale peptide panning and genome-wide CRISPR screening are protective against two Vibrio-borne toxins that cause disease, vPirAB and nigritoxin. Overlaying peptide panning on genetic screening reveals candidate peptides and a rationale for their inhibition, which could mimic binding between the toxin and the host receptor. For vPirAB, we have already conducted both screens, revealing partial overlap between the hits as predicted. Here, we propose to follow up on this finding by validating the genetic screens, optimizing the peptides using our cell culture model, testing the peptides on shrimp with a toxin challenge, and producing the expressed peptides cheaply in yeast. To our knowledge, this is the first merged application of these two approaches to identify host factors required for toxin activity and inhibitors, and could pave the way for expanded use of peptide therapeutics in aquaculture.