Modified horseshoe crab peptides target and kill bacteria inside host cells - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Access content directly
Journal Articles Cellular and Molecular Life Sciences Year : 2021

Modified horseshoe crab peptides target and kill bacteria inside host cells

Anna Amiss
Nicholas Condon
Peta Harvey
David Craik


Bacteria that occupy an intracellular niche can evade extracellular host immune responses and antimicrobial molecules. In addition to classic intracellular pathogens, other bacteria including uropathogenic Escherichia coli (UPEC) can adopt both extracellular and intracellular lifestyles. UPEC intracellular survival and replication complicates treatment, as many therapeutic molecules do not effectively reach all components of the infection cycle. In this study, we explored cell-penetrating antimicrobial peptides from distinct structural classes as alternative molecules for targeting bacteria. We identified two β-hairpin peptides from the horseshoe crab, tachyplesin I and polyphemusin I, with broad antimicrobial activity toward a panel of pathogenic and non-pathogenic bacteria in planktonic form. Peptide analogs [I11A]tachyplesin I and [I11S]tachyplesin I maintained activity toward bacteria, but were less toxic to mammalian cells than native tachyplesin I. This important increase in therapeutic window allowed treatment with higher concentrations of [I11A]tachyplesin I and [I11S]tachyplesin I, to significantly reduce intramacrophage survival of UPEC in an in vitro infection model. Mechanistic studies using bacterial cells, model membranes and cell membrane extracts, suggest that tachyplesin I and polyphemusin I peptides kill UPEC by selectively binding and disrupting bacterial cell membranes. Moreover, treatment of UPEC with sublethal peptide concentrations increased zinc toxicity and enhanced innate macrophage antimicrobial pathways. In summary, our combined data show that cell-penetrating peptides are attractive alternatives to traditional small molecule antibiotics for treating UPEC infection, and that optimization of native peptide sequences can deliver effective antimicrobials for targeting bacteria in extracellular and intracellular environments.


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Dates and versions

hal-04300472 , version 1 (22-11-2023)





Anna Amiss, Jessica von Pein, Jessica Webb, Nicholas Condon, Peta Harvey, et al.. Modified horseshoe crab peptides target and kill bacteria inside host cells. Cellular and Molecular Life Sciences, 2021, 79 (1), pp.38. ⟨10.1007/s00018-021-04041-z⟩. ⟨hal-04300472⟩


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