A peptide targeting outer membrane protein A of Acinetobacter baumannii exhibits antibacterial activity by reducing
1Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, Shaanxi, China.
Abstract:
The World Health Organization has classified multidrug-resistant (MDR) Acinetobacter baumannii as a significant threat to human health, necessitating the urgent discovery of new antibacterial drugs to combat bacterial resistance. Outer membrane protein A of A. baumannii (AbOmpA) is an outer membrane-anchored β-barrel-shaped pore protein that plays a critical role in bacterial adhesion, invasion, and biofilm formation. Therefore, AbOmpA is considered a key virulence factor of A. baumannii. Herein, we screened three phage display peptide libraries targeting AbOmpA and identified several peptides. Among them, P92 (amino acid sequence: QMGFMTSPKHSV) exhibited the highest binding affinity with AbOmpA, with a KD value of 7.84 nM. In vitro studies demonstrated that although P92 did not directly inhibit bacterial growth, it significantly reduced the invasion and adhesion capabilities of multiple clinical isolates of MDR A. baumannii and concentration-dependently inhibited biofilm formation by acting on OmpA. Furthermore, the polymerase chain reaction results confirmed a significant positive correlation between the antibacterial effect of P92 and OmpA expression levels. Encouragingly, P92 also displayed remarkable therapeutic efficacy against A. baumannii infection in various models, including an in vitro cell infection model, a mouse skin infection model, and a mouse sepsis model. These results highlight P92 as a novel and highly effective antimicrobial molecule specifically targeting the virulence factor AbOmpA.
Insights
A novel peptide, P92, effectively targets the multidrug-resistant Acinetobacter baumannii virulence factor, Outer Membrane Protein A (AbOmpA). P92 significantly reduces bacterial invasion, adhesion, and biofilm formation, showing therapeutic promise against infections.
Area of Science:
- Microbiology
- Drug Discovery
- Infectious Diseases
Background:
- Multidrug-resistant Acinetobacter baumannii is a major global health threat.
- Outer Membrane Protein A (AbOmpA) is a key virulence factor in A. baumannii, crucial for adhesion, invasion, and biofilm formation.
- New therapeutic strategies targeting virulence factors are urgently needed to combat bacterial resistance.
Purpose of the Study:
- To identify and characterize novel antimicrobial peptides targeting AbOmpA.
- To evaluate the efficacy of identified peptides against multidrug-resistant A. baumannii.
- To assess the therapeutic potential of lead peptide candidates in preclinical models.
Main Methods:
- Screening of phage display peptide libraries against AbOmpA.
- Affinity determination (KD) of peptide-AbOmpA interactions.
- In vitro assessment of peptide effects on bacterial adhesion, invasion, and biofilm formation.
- In vivo efficacy studies in cell culture, mouse skin, and sepsis models.
Main Results:
- Peptide P92 demonstrated high binding affinity to AbOmpA (KD = 7.84 nM).
- P92 significantly reduced A. baumannii invasion, adhesion, and biofilm formation in a concentration-dependent manner.
- A positive correlation was observed between P92's antibacterial effect and OmpA expression levels.
- P92 showed significant therapeutic efficacy in vitro and in vivo models of A. baumannii infection.
Conclusions:
- P92 is a potent antimicrobial peptide that specifically targets the AbOmpA virulence factor.
- P92 effectively inhibits key virulence mechanisms of multidrug-resistant A. baumannii.
- P92 represents a promising novel therapeutic candidate for treating A. baumannii infections.
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