Selective bacterial degradation of the extracellular matrix attaching the gingiva to the tooth

Abstract

The junctional epithelium (JE) is a specialized portion of the gingiva that seals off the tooth‐supporting tissues from the oral environment. This relationship is achieved via a unique adhesive extracellular matrix that is, in fact, a specialized basal lamina (sBL). Three unique proteins – amelotin (AMTN), odontogenic ameloblast‐associated (ODAM), and secretory calcium‐binding phosphoprotein proline‐glutamine rich 1 (SCPPPQ1) – together with laminin‐332 structure the supramolecular organization of this sBL and determine its adhesive capacity. Despite the constant challenge of the JE by the oral microbiome, little is known of the susceptibility of the sBL to bacterial degradation. Assays with trypsin‐like proteases, as well as incubation with Porphyromonas gingivalis, Prevotella intermedia, and Treponema denticola, revealed that all constituents, except SCPPPQ1, were rapidly degraded. Porphyromonas gingivalis was also shown to alter the supramolecular network of reconstituted and native sBLs. These results provide evidence that proteolytic enzymes and selected gram‐negative periodontopathogenic bacteria can attack this adhesive extracellular matrix, intimating that its degradation could contribute to progression of periodontal diseases.

A proline rich protein from the gingival seal around teeth exhibits antimicrobial properties against Porphyromonas gingivalis

“…The objective of our work was to better characterize the antibacterial potential of rat SCPPPQ1 protein, a structural matrix molecule produced by the JE that is resistant to bacterial degradation 13 . We have applied fluorescence and electron microscopy to evaluate whether SCPPPQ1 also has antimicrobial activity.…”

“…The SCPP gene cluster also encodes for a number of proteins possessing antimicrobial properties 21 , including some well-known AMPs such as Histatin1 14 . This link to the SCPP gene cluster, its proline rich nature, small size, and unique resistance to proteases 13 suggest that SCPPPQ1 may have antimicrobial capacity. To implicitly eliminate the null hypothesis (H0) that SCPPPQ1 has no antibacterial activity against P. gingivalis we have used a two-pronged approach that is, look for structural alterations and test for statistical difference between treatment parameters.…”

“…The keratinocytes of this JE produce a unique, adhesive extracellular matrix at the interface between the cells and the tooth surface 12 . While the focus has largely been on the destruction of connective tissue elements, we have recently shown that P. gingivalis can also affect the epithelially-derived adhesive matrix 13 . Three of its constituent proteins, Amelotin (AMTN), Odontogenic ameloblast-associated (ODAM) and Laminin-332 (Lam332) are rapidly and completely degraded by P. gingivalis 13 .…”

“…While the focus has largely been on the destruction of connective tissue elements, we have recently shown that P. gingivalis can also affect the epithelially-derived adhesive matrix 13 . Three of its constituent proteins, Amelotin (AMTN), Odontogenic ameloblast-associated (ODAM) and Laminin-332 (Lam332) are rapidly and completely degraded by P. gingivalis 13 . However, secretory calcium-binding phosphoprotein proline-glutamine rich 1 (SCPPPQ1) protein, is conspicuously resistant to degradation by P. gingivalis 13 .…”

“…Three of its constituent proteins, Amelotin (AMTN), Odontogenic ameloblast-associated (ODAM) and Laminin-332 (Lam332) are rapidly and completely degraded by P. gingivalis 13 . However, secretory calcium-binding phosphoprotein proline-glutamine rich 1 (SCPPPQ1) protein, is conspicuously resistant to degradation by P. gingivalis 13 . Therefore, SCPPPQ1 is the only of these 4 proteins implicated in the gingival adhesive “glue”, which is not affected by P. gingivalis .…”