Peptidoglycan Recognition Protein-S as a Dual-Action Antimicrobial and Immunomodulatory Agent Against Staphylococcus...

Area of Science:

• Biochemistry
• Immunology
• Microbiology

Background:

• The increasing prevalence of multidrug-resistant (MDR) pathogens like Staphylococcus aureus demands new therapeutic strategies.
• Peptidoglycan Recognition Protein-S (PGRP-S) is an innate immune protein that targets bacterial peptidoglycans.
• Camel milk is a natural source of PGRP-S, known for its immune-boosting properties.

Purpose of the Study:

• To investigate the antimicrobial and immunomodulatory potential of camel milk-derived PGRP-S (C-PGRP-S) against Staphylococcus aureus.
• To elucidate the mechanisms of action of C-PGRP-S.

Main Methods:

• Purification of C-PGRP-S and assessment of its antibacterial activity using MIC and time-kill kinetics assays.
• Scanning electron microscopy (SEM) to visualize bacterial morphological changes.
• Evaluation of immunomodulatory effects on macrophage cytokine production and reactive oxygen species (ROS) generation.

Main Results:

• C-PGRP-S demonstrated potent bactericidal activity, inhibiting S. aureus growth at 40 μg/mL and causing rapid cell death.
• SEM revealed dose-dependent damage to bacterial cell membranes.
• C-PGRP-S suppressed pro-inflammatory cytokine release and restored ROS production in M1 macrophages.

Conclusions:

• C-PGRP-S exhibits a dual mechanism of action: direct bacterial lysis and immune system modulation.
• Camel milk-derived PGRP-S is a promising therapeutic candidate for managing drug-resistant S. aureus infections.
• C-PGRP-S could serve as a natural alternative or adjunct to conventional antibiotics.