Bacteria degrade the specialized basal lamina attaches the gingiva to teeth
Bibliographic record
Abstract
Introduction The junctional epithelium is a specialized portion of the gingiva that seals off the tooth supporting tissues from the oral environment. This relationship is achieved via a specialized basal lamina (sBL). Three unique proteins ‐AMTN, ODAM and SCPPPQ1‐ together with Laminin‐332 structure the supramolecular organization of this sBL and determine its adhesive capacity. Despite its critical and strategic importance and continued exposure to bacteria, little is known on the susceptibility of the sBL to bacterial activity. Methods The objective of this study was to evaluate the impact of various oral bacteria on the sBL using molecular biology and complementary imaging approaches. Results SDS‐PAGE and western blot analysis of degradation assays with trypsin like proteases as well as incubation with Porphyromonas gingivalis ( P. gingivalis ) revealed that all sBL constituents, except SCPPPQ1, were rapidly degraded. Mass spectrometry also confirmed that SCPPPQ1 was not degraded. We have previously shown that mixing the recombinant sBL proteins results in the formation a supramolecular network that mimicked the sBL. To observe the impact of oral bacteria on this ‘reconstituted’ sBL network, we exposed it to P. gingivalis and observed the results by atomic force microscopy and scanning electron microscopy (SEM). The bacteria destroyed the supramolecular network in their vicinity creating a peripheral space around them. SEM imaging further showed the presence of fine filamentous residual matrix on the exposed HOPG surface, suggesting the incomplete degradation of some component and a layered destruction of the network. Finally, to determine the effect of P. gingivalis on the native sBL itself, we exposed it ex‐vivo to bacteria. After two hours of exposure, SEM analysis revealed the presence of a shallow depression around the bacteria and after 6 h, the affected peri‐bacterial area became deeper and cavitated , suggesting active degradation of the native sBL as well. Conclusion We show here for the first time that enzymes and P. gingivalis , one of the major bacteria implicated in chronic periodontitis, can attack the individual components of the sBL as well as alter the supramolecular organization of this critical adhesive extracellular matrix. Because destruction of the sBL would open the door to bacterial infiltration around teeth. These results highlight the importance of the sBL in PD and open the door for new treatment paradigms. Support or Funding Information This work was supported by CIHR, Canada Research Chair, RSBO, and Shriners Hospital. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".