Gelatinase-Responsive Short Peptide Conjugate as a Precision Therapy Against Methicillin-Resistant Staphylococcus...

Area of Science:

• Biochemistry and Molecular Biology
• Materials Science
• Infectious Diseases

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) presents a significant therapeutic challenge due to its widespread antibiotic resistance.
• Targeted antimicrobial strategies are needed to combat MRSA infections while preserving beneficial microflora.

Purpose of the Study:

• To design and synthesize a gelatinase-responsive peptide (Py-FGGK) for selective MRSA targeting.
• To evaluate the peptide's mechanism of action, including self-assembly and biofilm disruption.
• To assess the therapeutic efficacy and biocompatibility of Py-FGGK in preclinical models of MRSA infection and wound healing.

Main Methods:

• Synthesis of Py-FGGK, a peptide incorporating a pyrene fluorescent marker, a gelatinase-cleavable linker, and a heparan sulfate (HS)-binding motif.
• Characterization of peptide stability (serum half-life), HS binding affinity (isothermal calorimetry), and self-assembly.
• In vitro assays for biofilm disruption, cellular leakage, reactive oxygen species (ROS) generation, and cytotoxicity.
• In vivo studies in MRSA-infected rats to evaluate wound healing efficacy and biocompatibility assessments (hemolysis, cell viability).

Main Results:

• Py-FGGK demonstrated selective binding to HS on MRSA-infected sites, followed by gelatinase-mediated cleavage to release the active Py-FG peptide.
• The released Py-FG self-assembled into amyloid fibrils on MRSA surfaces, leading to significant antibacterial activity, biofilm disruption, and cell death.
• Py-FGGK promoted cellular migration, indicating potential for wound healing, and exhibited good biocompatibility with low cytotoxicity.

Conclusions:

• The developed peptide Py-FGGK offers a promising targeted therapeutic strategy against MRSA by leveraging a stimuli-responsive mechanism and self-assembling amyloid formation.
• Py-FGGK effectively combats MRSA biofilms and demonstrates potential for accelerating wound healing, supported by favorable biocompatibility profiles.
• This approach highlights the potential of rationally designed peptides in addressing antibiotic resistance and improving treatment outcomes for challenging infections.