Role of OmpA2 surface regions of Porphyromonas gingivalis in host-pathogen interactions with oral epithelial cells
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Updated: Mar 15, 2026
Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells
Published on: December 17, 2015
Kathryn L Naylor1, Magdalena Widziolek2, Stuart Hunt1
1School of Clinical Dentistry, University of Sheffield, Sheffield, United Kingdom.
Abstract:
Outer membrane protein A (OmpA) is a key outer membrane protein found in Gram-negative bacteria that contributes to several crucial processes in bacterial virulence. In Porphyromonas gingivalis, OmpA is predicted as a heterotrimer of OmpA1 and OmpA2 subunits encoded by adjacent genes. Here we describe the role of OmpA and its individual subunits in the interaction of P. gingivalis with oral cells. Using knockout mutagenesis, we show that OmpA2 plays a significant role in biofilm formation and interaction with human epithelial cells. We used protein structure prediction software to identify extracellular loops of OmpA2, and determined these are involved in interactions with epithelial cells as evidenced by inhibition of adherence and invasion of P. gingivalis by synthetic extracellular loop peptides and the ability of the peptides to mediate interaction of latex beads with human cells. In particular, we observe that OmpA2-loop 4 plays an important role in the interaction with host cells. These data demonstrate for the first time the important role of P. gingivalis OmpA2 extracellular loops in interaction with epithelial cells, which may help design novel peptide-based antimicrobial therapies for periodontal disease.
Insights
Outer membrane protein A2 (OmpA2) in Porphyromonas gingivalis is crucial for biofilm formation and interacting with human oral cells. Its extracellular loops, particularly loop 4, are key to these interactions, offering potential therapeutic targets for periodontal disease.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Oral Health
Background:
- Outer membrane protein A (OmpA) is vital for Gram-negative bacteria virulence.
- In Porphyromonas gingivalis, OmpA consists of OmpA1 and OmpA2 subunits.
- Understanding OmpA's role in P. gingivalis interaction with oral cells is crucial for treating periodontal disease.
Purpose of the Study:
- To investigate the role of OmpA and its subunits, particularly OmpA2, in the interaction of P. gingivalis with oral cells.
- To identify specific regions of OmpA2 involved in host cell interactions.
- To explore the potential of OmpA2 extracellular loops as therapeutic targets for periodontal disease.
Main Methods:
- Knockout mutagenesis to generate OmpA2-deficient P. gingivalis.
- Protein structure prediction to identify OmpA2 extracellular loops.
- Inhibition assays using synthetic OmpA2 extracellular loop peptides to block P. gingivalis adherence and invasion.
- Assays to test peptide-mediated interaction with human cells.
Main Results:
- OmpA2 significantly contributes to P. gingivalis biofilm formation and interaction with human epithelial cells.
- Extracellular loops of OmpA2 are involved in epithelial cell interactions.
- Synthetic peptides corresponding to OmpA2 extracellular loops inhibit P. gingivalis adherence and invasion.
- OmpA2-loop 4 is particularly important for host cell interaction.
- These peptides can mediate interactions between latex beads and human cells.
Conclusions:
- P. gingivalis OmpA2 plays a critical role in virulence by mediating interactions with host epithelial cells.
- OmpA2 extracellular loops are key functional domains for host cell engagement.
- OmpA2 extracellular loop peptides represent promising candidates for novel peptide-based antimicrobial therapies against periodontal disease.
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