Periodic Reporting for period 1 - miRs4Staph (Functional high-throughput analysis of the role of microRNAs in regulating Staphylococcus aureus infection)
Période du rapport: 2020-10-15 au 2022-10-14
Nowadays, it is known that S. aureus can live inside host cells and this intracellular lifestyle is crucial for infection dissemination and persistence. Also, intracellular bacteria may be protected from the activity of antimicrobials, leading to treatment failure and post-therapy relapse. In order to successfully invade and survive inside host cells, S. aureus needs to modulate host cell functions through several mechanisms. MiRNAs are small molecules present in host cells, which are capable of regulating cellular gene expression and, thus, influence the outcome of S. aureus infection.
In this context, the goal of this study was to discover miRNAs that regulate S. aureus invasion, survival, and replication within host cells. The knowledge of these factors may potentially reveal novel therapeutical targets to control S. aureus infection.
To increase the biological/clinical relevance of our findings, we validated the effect of this subset of 87 miRNAs on infection by S. aureus clinical isolates obtained from patients with different clinical manifestations, namely bone/joint infections, infective endocarditis and bacteraemia. We observed a strong conservation of the effect of the selected miRNAs on the infection and replication of the tested S. aureus isolates. We also performed time course experiments to determine which stages of S. aureus infection cycle were affected by specific miRNAs, and discovered that both the invasion and replication of S. aureus were regulated.
We have now selected two miRNAs that increase intracellular replication of S. aureus for detailed characterization, which is underway.
The results were presented by the Fellow at several advanced courses, meetings and conferences. An article describing the characterization of S. aureus intracellular lifestyles has been published, and additional manuscripts are expected. The Fellow participated in outreach activities, namely in the European Researcher’s Night.
Therefore, the knowledge acquired from this project on host mechanisms relevant for S. aureus infection may reveal novel targets for therapeutic intervention and thus lead to the development of novel antimicrobial therapies based on host targets rather than aiming at the pathogen, which has high capacity of acquiring antibiotic resistance.