Manipulation of hydrophobic motifs and optimization of sequence patterns to design high stability peptides against piglet bacterial infections

The risk of resistance to traditional antibiotics has led to a shift in attention to novel antimicrobial functional biomaterials. Antimicrobial peptides (AMPs) have been recognized since the date of birth as a powerful candidate for antibiotic replacement materials. However, immature salt and protease stability, as well as systemic toxicity, hinder the translation of AMPs from the bench to the bedside. Herein, the original motif (KP)3(HYXP)n(KP)3-NH2 (X = Trp or Phe, Y = Ile or Leu, n = 2, 3, 4, 5, or 6) was designed based on the principles of manipulating hydrophobic motifs, optimizing sequence patterns, as well as circumventing cleavage sites of proteases. Original motif was derived a 20-member library for obtaining AMPs with excellent antimicrobial activity, high salt, and protease stability. Results indicated that the target peptides HLFP-5 and HLWP-4 obtained using a comprehensive and integrated screening process exhibited excellent antibacterial ability, salts stability, and protease stability. Membrane cleavage and cell cycle interference-dominated mechanisms of action make target peptides less susceptible to drug resistance than antibiotics. Additionally, advanced target peptides HLFP-5 and HLWP-4 were able to exert direct antimicrobial efficacy in vivo to treat piglets with a systemic bacterial infection. Collectively, these findings may provide novel insights for future design principles, and help drive the application of antibacterial biomaterials in animal husbandry for replacing antibiotics.