Journal article
Impaired function of epithelial plakophilin-2 is associated with periodontal disease
Journal of periodontal research, Vol.56(6), pp.1046-1057
12/2021
DOI: 10.1111/jre.12918
PMCID: PMC8627832
PMID: 34368962
Abstract
Plakophilin-2 (PKP2) is an intracellular desmosomal anchoring protein that has been implicated in a genome-wide association study, in which genetic variants of PKP2 are associated with Porphyromonas gingivalis (P.gingivalis) -dominant periodontal dysbiosis. In this study, we compared the ex vivo PKP2 expression in periodontitis gingival biopsies to periodontitis-free subjects and assessed the in vitro role of PKP2 in gingival epithelial barrier function and the mechanism by which P.gingivalis modulates PKP2 expression.
Using reverse transcription quantitative real-time PCR (RT-qPCR), we determined PKP2 mRNA expression levels in gingival biopsies collected from 11 periodontally healthy, 10 experimental gingivitis, and 10 chronic periodontitis subjects. PKP2 protein expression in gingival biopsies was detected by immunohistochemistry. We then challenged primary gingival epithelial cells with bacteria including P.gingivalis, Campylobacter rectus, and various Toll-like receptor agonists. Western blot and immunofluorescence staining were used to detect protein expression. Inhibitors blocking proteases pathways were tested for P.gingivalis-mediated PKP2 protein degradations. We also knocked down endogenous epithelial PKP2 using lentiviral short-hairpin RNA (shRNA) and evaluated cell proliferation, spreading, and barrier function.
Periodontitis gingival biopsies had approximately twofold less PKP2 mRNA than did healthy controls (p < .05). PKP2 protein was predominantly expressed in gingival epithelium. In primary gingival epithelial cells, P.gingivalis challenge increased PKP2 mRNA levels, while protein expression decreased, which suggests that P.gingivalis has a protein degradation mechanism. Cysteine proteases inhibitors greatly attenuated P.gingivalis-mediated PKP2 protein degradation. Epithelial cells with deficient PKP2 exhibited inhibited cell proliferation and spreading and failed to form monolayers. Finally, P.gingivalis impaired gingival epithelial barrier function.
PKP2 appears to be critical in maintaining gingival epithelial barrier function and is susceptible to degradation by cysteine proteases produced by P.gingivalis. Our findings have identified a mechanism by which P.gingivalis impairs epithelial barrier function by promoting PKP2 degradation.
Details
- Title: Subtitle
- Impaired function of epithelial plakophilin-2 is associated with periodontal disease
- Creators
- Ning Yu - The Forsyth InstituteJinmei Zhang - University of IowaSherill T Phillips - University of North Carolina at Chapel HillSteven Offenbacher - University of North Carolina at Chapel HillShaoping Zhang - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Journal of periodontal research, Vol.56(6), pp.1046-1057
- DOI
- 10.1111/jre.12918
- PMID
- 34368962
- PMCID
- PMC8627832
- NLM abbreviation
- J Periodontal Res
- ISSN
- 0022-3484
- eISSN
- 1600-0765
- Grant note
- R90DE022527 / NIDCR NIH HHS K99 DE027086 / NIDCR NIH HHS R00 DE027086 / NIDCR NIH HHS R90 DE022527 / NIDCR NIH HHS R00DE027086 / NIDCR NIH HHS
- Language
- English
- Date published
- 12/2021
- Academic Unit
- Periodontics
- Record Identifier
- 9984367655502771
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