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Updated: Sep 4, 2025
A Mouse Model to Assess Innate Immune Response to Staphylococcus aureus Infection
Published on: February 28, 2019
Transcriptome change of Staphylococcus aureus in infected mouse liver
Hiroshi Hamamoto1, Suresh Panthee2,3, Atmika Paudel4
1Teikyo University Institute of Medical Mycology, 359 Otsuka, Hachio-ji shi, Tokyo, 192-0395, Japan.
Abstract:
We performed in vivo RNA-sequencing analysis of Staphylococcus aureus in infected mouse liver using the 2-step cell-crush method. We compared the transcriptome of S. aureus at 6, 24, and 48 h post-infection (h.p.i) in mice and in culture medium. Genes related to anaerobic respiration were highly upregulated at 24 and 48 h.p.i. The gene expression patterns of virulence factors differed depending on the type of toxin. For example, hemolysins, but not leukotoxins and serine proteases, were highly upregulated at 6 h.p.i. Gene expression of metal transporters, such as iron transporters, gradually increased at 24 and 48 h.p.i. We also analyzed the transcriptome of mouse liver infected with S. aureus. Hypoxia response genes were upregulated at 24 and 48 h.p.i., and immune response genes were upregulated from 6 h.p.i. These findings suggest that gene expression of S. aureus in the host changes in response to changes in the host environment, such as the oxygenation status or immune system attacks during infection.
Insights
Staphylococcus aureus gene expression shifts during mouse liver infection, adapting to host conditions like low oxygen and immune responses. This reveals bacterial survival strategies within the host environment.
Area of Science:
- Microbiology
- Infectious Diseases
- Genomics
Background:
- Staphylococcus aureus is a significant human pathogen causing diverse infections.
- Understanding bacterial adaptation within the host is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the in vivo transcriptome of Staphylococcus aureus during mouse liver infection.
- To compare bacterial gene expression in the host environment versus in vitro culture.
Main Methods:
- In vivo RNA-sequencing of Staphylococcus aureus in infected mouse liver using a 2-step cell-crush method.
- Transcriptome analysis at 6, 24, and 48 hours post-infection (h.p.i.) in mice and in culture medium.
Main Results:
- Bacterial genes for anaerobic respiration and iron transport were upregulated at later infection stages (24-48 h.p.i.).
- Virulence factor gene expression varied, with hemolysins upregulated early (6 h.p.i.) but not leukotoxins or serine proteases.
- Host mouse liver showed upregulated hypoxia response genes (24-48 h.p.i.) and immune response genes (from 6 h.p.i.).
Conclusions:
- Staphylococcus aureus dynamically alters its gene expression in response to the host environment, including oxygen levels and immune pressure.
- Bacterial adaptation mechanisms are evident, with distinct temporal regulation of virulence factors and metabolic pathways.
