Aurélien Fouillen (1,2), Charline Mary (1,2), Katia Julissa Ponce (2), Pierre Mofatt (3,4), Antonio Nanci (1,2)
Scientific Reports, 11, Issue 2353, January 2021. DOI: 10.1038/s41598-021-81791-7

Keywords

Antimicrobials; Bacteria; Proteins

Abstract

The gingival seal around teeth prevents bacteria from destroying the tooth-supporting tissues and disseminating throughout the body. Porphyromonas gingivalis, a major periodontopathogen, degrades components of the specialized extracellular matrix that mediates attachment of the gingiva to the tooth. Of these, secretory calcium-binding phosphoprotein proline-glutamine rich 1 (SCPPPQ1) protein has a distinctive resistance to degradation, suggesting that it may offer resistance to bacterial attack. In silico analysis of its amino acid sequence was used to explore its molecular characteristics and to predict its two- and three-dimensional structure. SCPPPQ1 exhibits similarities with both proline-rich and cationic antimicrobial proteins, suggesting a putative antimicrobial potential. A combination of imaging approaches showed that incubation with 20 μM of purified SCPPPQ1 decrease bacterial number (p<0.01). Fluorescence intensity decreased by 70% following a 2 h incubation of Porphyromonas gingivalis with the protein. Electron microscopy analyses revealed that SCPPPQ1 induced bacterial membrane disruption and breaches. While SCPPPQ1 has no effect on mammalian cells, our results suggest that it is bactericidal to Porphyromonas gingivalis, and that this protein, normally present in the gingival seal, may be exploited to maintain a healthy seal and prevent systemic dissemination of bacteria.

How Our Software Was Used

Dragonfly was used for the alignment and 3D reconstruction of FIB-SEM image stacks.

Author Affiliation

(1) Laboratory for the Study of Calcifed Tissues and Biomaterials, Faculty of Dental Medicine, Université de Montréal, Montreal, QC, Canada.
(2) Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada.
(3) Department of Human Genetics, McGill University, Montreal, QC, Canada.
(4) Shriners Hospitals for Children - Canada, Montreal, QC, Canada.