A novel antimicrobial peptide derived from membrane-proximal external region of human immunodeficiency virus type 1

Area of Science:

• Microbiology
• Biochemistry
• Drug Discovery

Background:

• Rising global antimicrobial drug resistance necessitates novel therapeutic strategies.
• Antimicrobial peptides (AMPs) are explored as potential alternatives due to their broad-spectrum activity.
• The membrane-proximal external region (MPER) of HIV-1 envelope protein serves as a basis for designing new AMPs.

Purpose of the Study:

• To design and evaluate synthetic peptides based on the HIV-1 MPER for antimicrobial properties.
• To identify a lead peptide with potent activity against Gram-negative and Gram-positive bacteria.
• To elucidate the mechanism of action and assess the safety profile of the lead peptide.

Main Methods:

• Design and synthesis of peptides inspired by the HIV-1 MPER.
• Antimicrobial activity testing using minimal bactericidal concentration (MBC) assays.
• Cytotoxicity evaluation in cell cultures and a mouse model.
• Confocal fluorescence microscopy and SYTOX Green uptake assays to determine bacterial killing mechanisms.

Main Results:

• Peptide AP16-A demonstrated significant antimicrobial activity against both Gram-negative and Gram-positive bacteria, with MBCs ranging from 2 to 16 μg/ml.
• AP16-A exhibited no detectable cytotoxicity in various tissue cultures and a mouse model.
• AP16-A employs a dual mechanism: slow membrane permeabilization and intracellular targeting for Gram-negative bacteria, and rapid membrane permeabilization for Gram-positive bacteria.

Conclusions:

• The synthetic peptide AP16-A shows potent antimicrobial efficacy and a favorable safety profile.
• AP16-A's distinct mechanisms of action against different bacterial types highlight its versatility.
• AP16-A represents a promising candidate for development as a novel antimicrobial agent to combat drug-resistant microbes.