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Published on: May 23, 2021
Proteomic analysis of Proteus mirabilis outer membrane proteins reveals differential expression in vivo vs. in vitro
Bruno D'Alessandro1, Leticia M S Lery, Wanda M A von Krüger
1Departamento de Microbiología, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.
Abstract:
Proteus mirabilis is an opportunistic pathogen that frequently causes complicated urinary tract infections. Among a wide spectrum of potential virulence factors, outer membrane proteins (OMPs) are critical for bacterial interactions and survival in different environments. In this work, we used a proteomic approach to assess P. mirabilis in vivo OMPs expression compared to in vitro, including iron replete and iron-restricted conditions. Three putative iron receptors, IreA, PMI0842, and PMI2596, were detected both in bacterium grown in vivo and in vitro under iron-restricted conditions. A prophage gene product, PMI1721, was detected only on in vivo growing bacterium, suggesting a potential role yet to be disclosed on the surface of P. mirabilis. Plasminogen, a host protein, was co-purified with OMPs of in vivo grown bacteria, which is in accordance with previous observations and suggests that plasminogen bound to P. mirabilis surface may be associated to virulence as seen in other bacterial pathogens. Western blots using sera of experimentally challenged mice showed that iron-regulated proteins are expressed and highly immunogenic during infection. This work confirms observations made by others for P. mirabilis and reveals details not yet described, suggesting new aspects of the bacterium pathogenesis that remain unknown.
Insights
Proteus mirabilis outer membrane proteins (OMPs) were analyzed in vivo versus in vitro. Iron-regulated OMPs are expressed and immunogenic during infection, suggesting roles in virulence.
Area of Science:
- Microbiology
- Proteomics
- Pathogenesis
Background:
- Proteus mirabilis is an opportunistic pathogen causing urinary tract infections.
- Outer membrane proteins (OMPs) are crucial for bacterial survival and interaction.
- Understanding OMPs in vivo is key to deciphering virulence factors.
Purpose of the Study:
- To compare in vivo and in vitro outer membrane protein expression of Proteus mirabilis.
- To identify iron-regulated outer membrane proteins and their expression patterns.
- To investigate the role of specific proteins and host interactions in P. mirabilis pathogenesis.
Main Methods:
- Proteomic analysis of P. mirabilis grown in vivo and in vitro under varying iron conditions.
- Identification of differentially expressed outer membrane proteins.
- Western blot analysis using sera from infected mice to assess immunogenicity.
Main Results:
- Three iron receptors (IreA, PMI0842, PMI2596) were identified in vivo and in vitro under iron restriction.
- A prophage gene product (PMI1721) was exclusively detected in vivo.
- Host plasminogen co-purified with in vivo OMPs, indicating potential virulence association.
- Iron-regulated proteins were found to be immunogenic during infection.
Conclusions:
- Proteomic analysis reveals distinct OMP profiles in vivo versus in vitro.
- Iron-regulated outer membrane proteins are immunogenic and likely contribute to P. mirabilis virulence.
- Further research into PMI1721 and plasminogen interaction may uncover novel virulence mechanisms.
