Secretome analysis and virulence assessment in Abiotrophia defectiva

Abstract

Background

Abiotrophia defectiva, although infrequently occurring, is a notable cause of culture-negative infective endocarditis with limited research on its virulence. Associated with oral infections such as dental caries, exploring its secretome may provide insights into virulence mechanisms. Our study aimed to analyze and characterize the secretome of A. defectiva strain CCUG 27639.

Methods

Secretome of A. defectiva was prepared from broth cultures and subjected to mass spectrometry and proteomics for protein identification. Inflammatory potential of the secretome was assessed by ELISA.

Results

Eighty-four proteins were identified, with diverse subcellular localizations predicted by PSORTb. Notably, 20 were cytoplasmic, 12 cytoplasmic membrane, 5 extracellular, and 9 cell wall-anchored proteins. Bioinformatics tools revealed 54 proteins secreted via the ‘Sec’ pathway and 8 via a non-classical pathway. Moonlighting functions were found in 23 proteins, with over 20 exhibiting potential virulence properties, including peroxiredoxin and oligopeptide ABC transporter substrate-binding protein. Gene Ontology and KEGG analyses categorized protein sequences in various pathways. STRING analysis revealed functional protein association networks. Cytokine profiling demonstrated significant proinflammatory cytokine release (IL-8, IL-1β, and CCL5) from human PBMCs.

Conclusions

Our study provides a comprehensive understanding of A. defectiva‘s secretome, laying the foundation for insights into its pathogenicity.

Keywords:

• Abiotrophia defectiva
• infective endocarditis
• secretome
• proteomics
• oral infections

Acknowledgments

This study was supported by Kuwait University Grant SRUL 01/14. We thank Dr. Nupur Sharma for critical reading and commenting on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

The raw data supporting the conclusions of this manuscript has been submitted to ‘PRIDE Archive’ (https://www.ebi.ac.uk/pride/archive/) repository with the project accession number PXD015631. The data files can be accessed with the username [email protected] and password: gCB24pty.

Ethics statement

This study was carried out in accordance with the recommendations of the Ethical Committee of Health Sciences Center (HSC), Kuwait University. Written informed consent was obtained from the human volunteer and the consent was in accordance with the Declaration of Helsinki. The protocol was approved by the Ethical Committee of the HSC, Kuwait University.

Author contribution statement

MK: Conceived and designed the study, bioinformatics analyses

RGB, MEK, MK: Performed the laboratory experiments, bioinformatics analyses

MK, RGB, MEK: Wrote the manuscript

Additional information

Funding

This study was funded by Kuwait University Grant SRUL 01/14.