Publications by authors named "Denis Kinane"

84 Publications

Decitabine Inhibits Bone Resorption in Periodontitis by Upregulating Anti-Inflammatory Cytokines and Suppressing Osteoclastogenesis.

Biomedicines 2021 Feb 17;9(2). Epub 2021 Feb 17.

Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.

DNA methylation controls several inflammatory genes affecting bone homeostasis. Hitherto, inhibition of DNA methylation in vivo in the context of periodontitis and osteoclastogenesis has not been attempted. Ligature-induced periodontitis in C57BL/6J mice was induced by placing ligature for five days with Decitabine (5-aza-2'-deoxycytidine) (1 mg/kg/day) or vehicle treatment. We evaluated bone resorption, osteoclast differentiation by tartrate-resistant acid phosphatase (TRAP) and mRNA expression of anti-inflammatory molecules using cluster differentiation 14 positive (CD14) monocytes from human peripheral blood. Our data showed that decitabine inhibited bone loss and osteoclast differentiation experimental periodontitis, and suppressed osteoclast CD14 human monocytes; and conversely, that it increased bone mineralization in osteoblastic cell line MC3T3-E1 in a concentration-dependent manner. In addition to increasing (interleukin-10), (transforming growth factor beta-1) in CD14 monocytes, decitabine upregulated KLF2 (Krüppel-like factor-2) expression. Overexpression of KLF2 protein enhanced the transcription of and On the contrary, site-directed mutagenesis of binding site in and abrogated luciferase activity in HEK293T cells. Decitabine reduces bone loss in a mouse model of periodontitis by inhibiting osteoclastogenesis through the upregulation of anti-inflammatory cytokines via KLF2 dependent mechanisms. DNA methyltransferase inhibitors merit further investigation as a possible novel therapy for periodontitis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/biomedicines9020199DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7922804PMC
February 2021

TLR3-Dependent Activation of TLR2 Endogenous Ligands via the MyD88 Signaling Pathway Augments the Innate Immune Response.

Cells 2020 08 17;9(8). Epub 2020 Aug 17.

Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19004, USA.

The role of the adaptor molecule MyD88 is thought to be independent of Toll-like receptor 3 (TLR3) signaling. In this report, we demonstrate a previously unknown role of MyD88 in TLR3 signaling in inducing endogenous ligands of TLR2 to elicit innate immune responses. Of the various TLR ligands examined, the TLR3-specific ligand polyinosinic:polycytidylic acid (poly I:C), significantly induced TNF production and the upregulation of other TLR transcripts, in particular, TLR2. Accordingly, TLR3 stimulation also led to a significant upregulation of endogenous TLR2 ligands mainly, HMGB1 and Hsp60. By contrast, the silencing of TLR3 significantly downregulated MyD88 and TLR2 gene expression and pro-inflammatory IL1β, TNF, and IL8 secretion. The silencing of MyD88 similarly led to the downregulation of TLR2, IL1β, TNF and IL8, thus suggesting MyD88 to somehow act downstream of TLR3. Corroborating in vitro data, Myd88 knockout mice downregulated TNF, CXCL1; and phospho-p65 and phospho-IRF3 nuclear localization, upon poly I:C treatment in a mouse model of skin infection. Taken together, we identified a previously unknown role for MyD88 in the TLR3 signaling pathway, underlying the importance of TLRs and adapter protein interplay in modulating endogenous TLR ligands culminating in pro-inflammatory cytokine regulation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cells9081910DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7464415PMC
August 2020

Distinct Signaling Pathways Between Human Macrophages and Primary Gingival Epithelial Cells by .

Pathogens 2020 Mar 27;9(4). Epub 2020 Mar 27.

Department of Periodontology, School of Dental Medicine, University of Geneva Faculty of Medicine, Geneve 12114, Switzerland.

In aggressive periodontitis, the dysbiotic microbial community in the subgingival crevice, which is abundant in Aggregatibacter actinomycetemcomitans, interacts with extra- and intracellular receptors of host cells, leading to exacerbated inflammation and subsequent tissue destruction. Our goal was to understand the innate immune interactions of A. actinomycetemcomitans with macrophages and human gingival epithelial cells (HGECs) on the signaling cascade involved in inflammasome and inflammatory responses. U937 macrophages and HGECs were co-cultured with A. actinomycetemcomitans strain Y4 and key signaling pathways were analyzed using real-time PCR, Western blotting and cytokine production by ELISA. A. actinomycetemcomitans infection upregulated the transcription of TLR2, TLR4, NOD2 and NLRP3 in U937 macrophages, but not in HGECs. Transcription of IL-1β and IL-18 was upregulated in macrophages and HGECs after 1 h interaction with A. actinomycetemcomitans, but positive regulation persisted only in macrophages, resulting in the presence of IL-1β in macrophage supernatant. Immunoblot data revealed that A. actinomycetemcomitans induced the phosphorylation of AKT and ERK1/2, possibly leading to activation of the NF-κB pathway in macrophages. On the other hand, HGEC signaling induced by A. actinomycetemcomitans was distinct, since AKT and 4EBP1 were phosphorylated after stimulation with A. actinomycetemcomitans, whereas ERK1/2 was not. Furthermore, A. actinomycetemcomitans was able to induce the cleavage of caspase-1 in U937 macrophages in an NRLP3-dependent pathway. Differences in host cell responses, such as those seen between HGECs and macrophages, suggested that survival of A. actinomycetemcomitans in periodontal tissues may be favored by its ability to differentially activate host cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/pathogens9040248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7238148PMC
March 2020

Epigenetic and inflammatory events in experimental periodontitis following systemic microbial challenge.

J Clin Periodontol 2019 08 25;46(8):819-829. Epub 2019 Jun 25.

Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Aim: The purpose of this study was to determine inflammatory and epigenetic features following induction of oral and gut dysbiosis in experimental periodontitis in order to examine the interplay between oral and systemic infection.

Materials And Methods: Periodontitis was induced in 6- to 8-week-old C57BL/6 mice by (a) Ligature placement (Lig group) (oral challenge); (b) P. gingivalis gavage (Pg group) (systemic challenge); and (c) the combination of the two models oral and systemic challenge (Pg + Lig). The duration of the experiment was 60 days, and the animals were then sacrificed for analyses. Alveolar bone loss was assessed, and a multiplex immunoassay was performed. Maxillae and gut tissues were immunostained for DNMT3b (de novo methylation marker), B and T lymphocyte attenuator (BTLA) and IL-18R1 (inflammation markers).

Results: Pg and Pg + Lig groups exhibited higher bone loss when compared to Sham. BAFF, VEGF, RANKL, RANTES and IP-10 were significantly higher with Pg gavage. Likewise, DNMT3b was overexpressed in both gut and maxilla after the Pg administration. The same pattern was observed for BTLA and IL-18R1 in gut tissues.

Conclusions: The systemic microbial challenge either alone or in combination with local challenge leads to distinct patterns of inflammatory and epigenetic features when compared to simply locally induced experimental periodontitis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcpe.13151DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6641985PMC
August 2019

IFN-β secretion is through TLR3 but not TLR4 in human gingival epithelial cells.

Mol Immunol 2019 07 4;111:27-31. Epub 2019 Apr 4.

Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia PA 19004, USA. Electronic address:

The oral cavity is home for a plethora of bacteria and viruses. Epithelial barriers encounter these micro-organisms and recognize them via pathogen recognition receptors (PRRs) that instigate antibacterial and antiviral responses. We and others have shown that human gingival epithelial cells (HGECs) express PRRs to defend invading pathogens. Among these PRRs, TLR2, TLR3 and TLR4 are highly expressed in HGECs and appear to be important based on our previous findings. IFN-β is one of the major type 1 interferons induced to defend viral attack. In this report, we sought to dissect TLR3 and TLR4 mediated secretion of IFN-β in HGECs. We stimulated HGECs with ultrapure LPS (TLR4 ligand) and Poly I:C (TLR3 ligand) for 24 h and supernatant was used to determine IFN-β secretion. We show that cells treated with Poly I:C induced IFN-β secretion but not cells treated with LPS. In addition, silencing of TLR3 prior to Poly I:C stimulation significantly downregulated IFN-β secretion. On the contrary, overexpression of MD2 and TLR4 in HGECs restored IFN-β secretion. Upon further evaluation, we found that TLR3 stimulation but not TLR4 induced the phosphorylation of interferon regulatory factor 3 (IRF3), which is critical for IFN-β secretion. We conclude that IFN-β secretion is through TLR3 and not via TLR4 in HGECs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.molimm.2019.03.006DOI Listing
July 2019

Role of NOD1/NOD2 receptors in Fusobacterium nucleatum mediated NETosis.

Microb Pathog 2019 Jun 30;131:53-64. Epub 2019 Mar 30.

Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA. Electronic address:

Polymorphonuclear neutrophils (PMNs) are indispensable in fighting infectious microbes by adopting various antimicrobial strategies including phagocytosis and neutrophil extracellular traps (NETs). Although the role and importance of PMNs in periodontal disease are well established, the specific molecular mechanisms involved in NET formation are yet to be characterized. In the present study, we sought to determine the role of periodontal pathogen on NET formation by utilizing Fusobacterium nucleatum. Our data demonstrates that F. nucleatum activates neutrophils and induces robust NETosis in a time-dependent manner via the upregulation of the Nucleotide oligomerization domain 1 (NOD1) and NOD2 receptors. Furthermore, CRISPR/Cas9 knockout of HL-60 cells and the use of ligands/inhibitors confirmed the involvement of NOD1 and NOD2 receptors in F. nucleatum-mediated NET formation. When treated with NOD1 and NOD2 inhibitors, we observed a significant downregulation of peptidylarginine deiminase 4 (PAD4) activity. In addition, neutrophils showed a significant increase and decrease of myeloperoxidase (MPO) and neutrophil elastase (NE) when treated with NOD1/NOD2 ligands and inhibitors, respectively. Taken together, CRISPR/Cas9 knockout of NOD1/NOD2 HL-60 cells and inhibitors of NOD signaling confirmed the role of NLRs in F. nucleatum-mediated NETosis. Our data demonstrates an important pathway linking NOD1 and NOD2 to NETosis by F. nucleatum, a prominent microbe in periodontal biofilms. This is the first study to elucidate the role of NOD-like receptors in NETosis and their downstream signaling network.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.micpath.2019.03.036DOI Listing
June 2019

Meeting report: a close look at oral biofilms and microbiomes.

Int J Oral Sci 2018 08 15;10(3):28. Epub 2018 Aug 15.

State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.

The "Biofilms, Microbiomes and Oral Diseases: Challenges and Future Perspectives" symposium jointly organized by Penn Dental Medicine and West China School of Stomatology was held on 30 September 2017 at Penn Wharton China Center (PWCC) in Beijing, China. The topics included the pathogenicity of oral biofilms, novel strategies for the control of biofilm-related diseases, oral microbiome and single-cell approaches, and the link between oral diseases and overall health. Researchers from a number of disciplines, representing institutions from China and Penn Dental Medicine, gathered to discuss advances in our understanding of biofilms, as well as future directions for the control of biofilm-related oral and systemic diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41368-018-0030-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6093876PMC
August 2018

Periodontitis: Consensus report of workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

J Periodontol 2018 06;89 Suppl 1:S173-S182

University of Hong Kong, Hong Kong, SAR China.

A new periodontitis classification scheme has been adopted, in which forms of the disease previously recognized as "chronic" or "aggressive" are now grouped under a single category ("periodontitis") and are further characterized based on a multi-dimensional staging and grading system. Staging is largely dependent upon the severity of disease at presentation as well as on the complexity of disease management, while grading provides supplemental information about biological features of the disease including a history-based analysis of the rate of periodontitis progression; assessment of the risk for further progression; analysis of possible poor outcomes of treatment; and assessment of the risk that the disease or its treatment may negatively affect the general health of the patient. Necrotizing periodontal diseases, whose characteristic clinical phenotype includes typical features (papilla necrosis, bleeding, and pain) and are associated with host immune response impairments, remain a distinct periodontitis category. Endodontic-periodontal lesions, defined by a pathological communication between the pulpal and periodontal tissues at a given tooth, occur in either an acute or a chronic form, and are classified according to signs and symptoms that have direct impact on their prognosis and treatment. Periodontal abscesses are defined as acute lesions characterized by localized accumulation of pus within the gingival wall of the periodontal pocket/sulcus, rapid tissue destruction and are associated with risk for systemic dissemination.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/JPER.17-0721DOI Listing
June 2018

Periodontitis: Consensus report of workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

J Clin Periodontol 2018 06;45 Suppl 20:S162-S170

University of Hong Kong, Hong Kong, SAR China.

A new periodontitis classification scheme has been adopted, in which forms of the disease previously recognized as "chronic" or "aggressive" are now grouped under a single category ("periodontitis") and are further characterized based on a multi-dimensional staging and grading system. Staging is largely dependent upon the severity of disease at presentation as well as on the complexity of disease management, while grading provides supplemental information about biological features of the disease including a history-based analysis of the rate of periodontitis progression; assessment of the risk for further progression; analysis of possible poor outcomes of treatment; and assessment of the risk that the disease or its treatment may negatively affect the general health of the patient. Necrotizing periodontal diseases, whose characteristic clinical phenotype includes typical features (papilla necrosis, bleeding, and pain) and are associated with host immune response impairments, remain a distinct periodontitis category. Endodontic-periodontal lesions, defined by a pathological communication between the pulpal and periodontal tissues at a given tooth, occur in either an acute or a chronic form, and are classified according to signs and symptoms that have direct impact on their prognosis and treatment. Periodontal abscesses are defined as acute lesions characterized by localized accumulation of pus within the gingival wall of the periodontal pocket/sulcus, rapid tissue destruction and are associated with risk for systemic dissemination.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcpe.12946DOI Listing
June 2018

Authors' reply: Predictive diagnostic tests in periodontal diseases.

Nat Rev Dis Primers 2017 09 14;3:17070. Epub 2017 Sep 14.

Columbia University College of Dental Medicine, New York, New York, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/nrdp.2017.70DOI Listing
September 2017

Periodontal diseases.

Nat Rev Dis Primers 2017 Jun 22;3:17038. Epub 2017 Jun 22.

Columbia University College of Dental Medicine, New York, New York, USA.

Periodontal diseases comprise a wide range of inflammatory conditions that affect the supporting structures of the teeth (the gingiva, bone and periodontal ligament), which could lead to tooth loss and contribute to systemic inflammation. Chronic periodontitis predominantly affects adults, but aggressive periodontitis may occasionally occur in children. Periodontal disease initiation and propagation is through a dysbiosis of the commensal oral microbiota (dental plaque), which then interacts with the immune defences of the host, leading to inflammation and disease. This pathophysiological situation persists through bouts of activity and quiescence, until the affected tooth is extracted or the microbial biofilm is therapeutically removed and the inflammation subsides. The severity of the periodontal disease depends on environmental and host risk factors, both modifiable (for example, smoking) and non-modifiable (for example, genetic susceptibility). Prevention is achieved with daily self-performed oral hygiene and professional removal of the microbial biofilm on a quarterly or bi-annual basis. New treatment modalities that are actively explored include antimicrobial therapy, host modulation therapy, laser therapy and tissue engineering for tissue repair and regeneration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/nrdp.2017.38DOI Listing
June 2017

A Building with a Provenance: The Thomas W. Evans Building at Penn Dental Medicine.

Authors:
Denis F Kinane

J Hist Dent 2017 ;65(1):7-15

Penn Dental Medicine, University of Pennsylvania.

View Article and Find Full Text PDF

Download full-text PDF

Source
July 2018

Investigation of the functional role of human Interleukin-8 gene haplotypes by CRISPR/Cas9 mediated genome editing.

Sci Rep 2016 08 8;6:31180. Epub 2016 Aug 8.

Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.

Interleukin-8 (IL-8) gene polymorphisms have been considered as susceptibility factors in periodontal disease. However, the functional roles of IL-8 gene haplotypes have not been investigated. Here, we demonstrate for the first time the use of the CRISPR/Cas9 system to engineer the IL-8 gene, and tested the functionality of different haplotypes. Two sgRNAs vectors targeting the IL-8 gene and the naked homologous repair DNA carrying different haplotypes were used to successfully generate HEK293T cells carrying the AT genotype at the first SNP - rs4073 (alias -251), TT genotype at the second SNP - rs2227307 (alias +396), TC or CC genotypes at the third SNP - rs2227306 (alias +781) at the IL-8 locus. When stimulated with Poly I:C, ATC/TTC haplotype, cells significantly up-regulated the IL-8 at both transcriptional and translational levels. To test whether ATC/TTC haplotype is functional, we used a trans-well assay to measure the transmigration of primary neutrophils incubated with supernatants from the Poly I:C stimulation experiment. ATC/TTC haplotype cells significantly increased transmigration of neutrophils confirming the functional role for this IL-8 haplotype. Taken together, our data provides evidence that carriage of the ATC/TTC haplotype in itself may increase the influx of neutrophils in inflammatory lesions and influence disease susceptibility.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep31180DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4976357PMC
August 2016

The B Cell-Stimulatory Cytokines BLyS and APRIL Are Elevated in Human Periodontitis and Are Required for B Cell-Dependent Bone Loss in Experimental Murine Periodontitis.

J Immunol 2015 Aug 6;195(4):1427-35. Epub 2015 Jul 6.

Department of Microbiology, Penn Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104;

B-lineage cells (B lymphocytes and plasma cells) predominate in the inflammatory infiltrate of human chronic periodontitis. However, their role in disease pathogenesis and the factors responsible for their persistence in chronic lesions are poorly understood. In this regard, two cytokines of the TNF ligand superfamily, a proliferation-inducing ligand (APRIL) and B-lymphocyte stimulator (BLyS), are important for the survival, proliferation, and maturation of B cells. Thus, we hypothesized that APRIL and/or BLyS are upregulated in periodontitis and contribute to induction of periodontal bone loss. This hypothesis was addressed in both human and mouse experimental systems. We show that, relative to healthy controls, the expression of APRIL and BLyS mRNA and protein was upregulated in natural and experimental periodontitis in humans and mice, respectively. The elevated expression of these cytokines correlated with increased numbers of B cells/plasma cells in both species. Moreover, APRIL and BLyS partially colocalized with κ L chain-expressing B-lineage cells at the epithelial-connective tissue interface. Ligature-induced periodontitis resulted in significantly less bone loss in B cell-deficient mice compared with wild-type controls. Ab-mediated neutralization of APRIL or BLyS diminished the number of B cells in the gingival tissue and inhibited bone loss in wild-type, but not in B cell-deficient, mice. In conclusion, B cells and specific cytokines involved in their growth and differentiation contribute to periodontal bone loss. Moreover, APRIL and BLyS have been identified as potential therapeutic targets in periodontitis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4049/jimmunol.1500496DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4530049PMC
August 2015

Host response in aggressive periodontitis.

Periodontol 2000 2014 Jun;65(1):79-91

It is critical to understand the underlying host responses in aggressive periodontitis to provide a better appreciation of the risk and susceptibility to this disease. Such knowledge may elucidate the etiology and susceptibility to aggressive periodontitis and directly influence treatment decisions and aid diagnosis. This review is timely in that several widely held tenets are now considered unsupportable, namely the concept that Aggregatibacter actinomycetemycomitans is the key pathogen and that chemotactic defects in polymorphonuclear leukocytes are part of the etiopathology. This review also serves to put into context key elements of the host response that may be implicated in the genetic background of aggressive periodontitis. Furthermore, key molecules unique to the host response in aggressive periodontitis may have diagnostic utility and be used in chairside clinical activity tests or as population screening markers. It is becoming increasingly appreciated that the microbial etiology of aggressive periodontitis and the histopathology of this disease are more similar to than different from that of chronic periodontitis. An important therapeutic consideration from the lack of support for A. actinomycetemycomitans as a critical pathogen here is that the widely held belief that tetracycline had a role in aggressive periodontitis therapy is now not supported and that antibiotics such as those used effectively in chronic periodontitis (metronidazole and amoxicillin) are not contraindicated. Furthermore, A. actinomycetemycomitans-related molecules, such as cytolethal distending toxin and leukotoxin, are less likely to have utility as diagnosis agents or as therapeutic targets.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/prd.12017DOI Listing
June 2014

P. gingivalis modulates keratinocytes through FOXO transcription factors.

PLoS One 2013 12;8(11):e78541. Epub 2013 Nov 12.

Department of Implant Dentistry, Peking University, School and Hospital of Stomatology, Beijing, China ; Departments of Pathology and Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

P. gingivalis is a prominent periodontal pathogen that has potent effects on host cells. In this study we challenged gingival epithelial cells with P. gingivalis with the aim of assessing how mRNA levels of key target genes were modulated by P. gingivalis via the transcription factors FOXO1 and FOXO3. Primary mono- and multi-layer cultures of gingival epithelial cells were challenged and barrier function was examined by fluorescent dextran and apoptosis was measured by cytoplasmic histone associated DNA. Gene expression levels were measured by real-time PCR with and without FOXO1 and FOXO3 siRNA compared to scrambled siRNA. P. gingivalis induced a loss of barrier function and stimulated gingival epithelial cell apoptosis in multilayer cultures that was in part gingipain dependent. P. gingivalis stimulated an increase in FOXO1 and FOXO3 mRNA, enhanced mRNA levels of genes associated with differentiated keratinocyte function (keratin-1, -10, -14, and involucrin), increased mRNA levels of apoptotic genes (BID and TRADD), reduced mRNA levels of genes that regulate inflammation (TLR-2 and -4) and reduced those associated with barrier function (integrin beta-1, -3 and -6). The ability of P. gingivalis to modulate these genes was predominantly FOXO1 and FOXO3 dependent. The results indicate that P. gingivalis has pronounced effects on gingival keratinocytes and modulates mRNA levels of genes that affect host response, differentiation, apoptosis and barrier function. Moreover, this modulation is dependent upon the transcription factors FOXO1 or FOXO3. In addition, a new function for FOXO1 was identified, that of suppressing TLR-2 and TLR-4 and maintaining integrin beta -1, beta -3 and beta -6 basal mRNA levels in keratinocytes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0078541PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3827038PMC
September 2014

Influence of periodontal disease, Porphyromonas gingivalis and cigarette smoking on systemic anti-citrullinated peptide antibody titres.

J Clin Periodontol 2013 Oct 1;40(10):907-15. Epub 2013 Aug 1.

Infection and Immunity, University of Glasgow Dental School, School of Medicine, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, UK.

Background: Anti-citrullinated protein antibody (ACPA) responses may precede clinical onset of rheumatoid arthritis. Porphyromonas gingivalis peptidylarginine deiminase can citrullinate proteins possibly inducing autoimmunity in susceptible individuals.

Aim: To determine whether periodontitis, carriage of P. gingivalis, smoking and periodontal therapy influence ACPA titres.

Methods: Serum and plaque samples were collected from 39 periodontitis patients before and after non-surgical periodontal treatment, and from 36 healthy subjects. Carriage of P. gingivalis was determined by PCR of plaque DNA. ACPA was determined by anti-cyclic citrullinated peptide (CCP) enzyme-linked immunosorbent assay (ELISA). Anti-P. gingivalis titres were determined by ELISA.

Results: Untreated periodontitis patients had higher anti-CCP antibody titres than healthy controls [three patients (8%) greater than manufacturer suggested assay diagnostic threshold (5 Assay Units/AU) versus none (0%); mean ± SEM: 1.37 ± 0.23 versus 0.40 ± 0.10 AU, p < 0.0001]. Periodontitis patients who smoked demonstrated lower anti-P. gingivalis (15956 ± 4385 versus 2512 ± 1290 Units/ml, p < 0.05), but similar anti-CCP than non-smoking periodontitis patients (smokers: 1.31 ± 0.35; non-smokers: 1.41 ± 0.32 AU). Healthy smokers demonstrated elevated anti-CCP titres (0.75 ± 0.19 AU), at levels between healthy non-smokers (0.15 ± 0.05 AU) and non-smoker periodontitis patients. Six months after periodontal treatment, there were significant reductions in anti-CCP (non-smokers p < 0.05) and anti-P. gingivalis (all participants p < 0.01).

Conclusion: In subjects with periodontitis, P. gingivalis infection may be responsible for inducing autoimmune responses that characterize rheumatoid arthritis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcpe.12138DOI Listing
October 2013

Periodontal therapy in chronic periodontitis lowers gingival crevicular fluid interleukin-1beta and DAS28 in rheumatoid arthritis patients.

Rheumatol Int 2013 Oct 1;33(10):2607-16. Epub 2013 Jun 1.

Department of Periodontology, School of Dentistry, Ege University, Bornova, 35100, Izmir, Turkey.

To evaluate clinical outcomes and effects of non-surgical periodontal therapy on serum, gingival crevicular fluid (GCF) interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) levels in chronic periodontitis patients with/without rheumatoid arthritis (RA), fifteen RA patients with chronic periodontitis (RA-P) and 15 systemically healthy non-RA chronic periodontitis patients (H-P) were recruited. Clinical periodontal recordings, GCF, and blood samples were obtained at baseline, 1, 3, and 6 months after periodontal treatment. GCF, serum IL-1β, TNF-α levels were analyzed by ELISA. Disease activity score 28 (DAS28) was used to assess RA clinical morbidity. Study groups were compared by Mann-Whitney U test. Wilcoxon test was used to compare the data at baseline, 1, 3, and 6 months after periodontal therapy within the same group. DAS28 decreased significantly after periodontal therapy in RA-P group (p < 0.01). Serum TNF-α concentrations of H-P group were significantly higher than those of RA-P group (p < 0.01), whereas IL-1β levels were similar. No significant change was observed in serum levels of these cytokines after periodontal therapy. GCF IL-1β amounts decreased significantly in both groups following treatment (p < 0.01). At 6-months, H-P GCF IL-1β concentrations were significantly lower than baseline. DAS28 and GCF IL-1β correlated with clinical periodontal indices (p < 0.01). Significant decreases in DAS28 and GCF IL-1β amounts after periodontal treatment suggest that periodontal therapy synergizes with systemic RA therapy to improve RA status.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00296-013-2781-5DOI Listing
October 2013

Porphyromonas gingivalis influences actin degradation within epithelial cells during invasion and apoptosis.

Cell Microbiol 2012 Jul 28;14(7):1085-96. Epub 2012 Mar 28.

Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.

Porphyromonas gingivalis, a Gram-negative oral pathogen, has been shown to induce apoptosis in human gingival epithelial cells, yet the underlining cellular mechanisms controlling this process are poorly understood. We have previously shown that the P. gingivalis proteases arginine and lysine gingipains, are necessary and sufficient to induce host cell apoptosis. In the present study, we demonstrate that 'P. gingivalis-induced apoptosis' is mediated through degradation of actin leading to cytoskeleton collapse. Stimulation of human gingival epithelial cells with P. gingivalis strains 33277 and W50 at moi:100 induced β-actin cleavage as early as 1 h and human serum inhibited this effect. By using gingipain-deficient mutants of P. gingivalis and purified gingipains, we demonstrate that lysine gingipain is involved in actin hydrolysis in a dose and time-dependent manner. Use of Jasplakinolide and cytochalasin D revealed that P. gingivalis internalization is necessary for actin cleavage. Further, we also show that lysine gingipain from P. gingivalis can cleave active caspase 3. Taken together, we have identified actin as a substrate for lysine gingipain and demonstrated a novel mechanism involved in microbial host cell invasion and apoptosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1462-5822.2012.01780.xDOI Listing
July 2012

Mapping biological to clinical phenotypes during the development (21 days) and resolution (21 days) of experimental gingivitis.

J Clin Periodontol 2012 Feb 12;39(2):123-31. Epub 2011 Dec 12.

Unilever Oral Care, Bebington, UK.

Aim: To characterize and map temporal changes in the biological and clinical phenotype during a 21-day experimental gingivitis study.

Materials And Methods: Experimental gingivitis was induced over 21 days in healthy human volunteers (n = 56), after which normal brushing was resumed (resolution phase). Gingival and plaque indices were assessed. Gingival crevicular fluid was collected from four paired test and contra-lateral control sites in each volunteer during induction (Days 0, 7, 14 and 21) and resolution (Days 28 and 42) of experimental gingivitis. Fluid volumes were measured and a single analyte was quantified from each site-specific, 30s sample. Data were evaluated by analysis of repeated measurements and paired sample tests.

Results: Clinical indices and gingival crevicular fluid volumes at test sites increased from Day 0, peaking at Day 21 (test/control differences all p < 0.0001) and decreased back to control levels by Day 28. Levels of four inflammatory markers showed similar patterns, with significant differences between test and control apparent at Day 7 (substance P, cathepsin G, interleukin-1β, elastase: all p < 0.03) and peaking at Day 21 (all p < 0.002). Levels of α-1-antitrypsin showed no pattern.

Conclusions: Levels of substance P, cathepsin G, interleukin-1β and neutrophil elastase act as objective biomarkers of gingival inflammation induction and resolution that typically precede phenotypical changes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1600-051X.2011.01825.xDOI Listing
February 2012

Innate cellular responses to the periodontal biofilm.

Front Oral Biol 2012 11;15:41-55. Epub 2011 Nov 11.

Department of Periodontics, University of Pennsylvania, Philadelphia, PA, USA.

This chapter addresses the host responses to the microbial biofilm that constitutes the subgingival dental plaque. The host response to infection draws upon the innate, inflammatory and adaptive immune systems, whose role is to provide the appropriate response to the offending microorganisms. In some cases, this will be little or no response when encountering 'commensals', and in other cases a gradated response depending very much on the host's own determination of the pathogenic nature of the microbial insult: and herein lies the root of variation in host responses that govern individual susceptibility. In some individuals and with some bacteria this will be an innate-only response, others will need to invoke the inflammatory response, and yet others will require the adaptive immune response - be it cellular, humoral or both - to reduce or remove the challenge from the microbes. Of course these responses would be somewhat easier to predict with a single pathogen challenge, and become infinitely more complex as the biofilm increases in complexity. Oral infections, in particular gingival inflammation, originate from not just one but many microorganisms. This polymicrobial infection may result in chronic inflammation, which may lead to tissue destruction, as evident in chronic periodontitis. Although many organisms are present in the subgingival biofilm, interestingly, the putative pathogens associated with gingivitis and periodontitis may comprise very small fractions of the total biomass. An understanding of the interaction of structural and defensive host cells with the biofilm is pivotal to understanding periodontal disease etiology and to developing tailored therapeutics. Thus, this chapter addresses the main structural cells, i.e. epithelial cells, exposed to the biofilm.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000329670DOI Listing
January 2012

Host-response: understanding the cellular and molecular mechanisms of host-microbial interactions--consensus of the Seventh European Workshop on Periodontology.

J Clin Periodontol 2011 Mar;38 Suppl 11:44-8

University of Pensylvania School of Dental Medicine, 240 South 40th Street, Philadelphia, PA 19104-6030, USA.

Background: Major challenges in periodontology include understanding the pathophysiology, the interplay between various components of the host response, parallels with other diseases and identifying biomarkers of the disease.

Objectives: Four reviews were compiled with the aim of better understanding: (1) the role of polymorphic nuclear leucocytes (PMNs), i.e. neutrophils; (2) the function of cytokine networks in the host response; (3) whether parallels exist with rheumatoid arthritis (RA); and (4) whether useful biomarkers currently exist to help in the management of periodontal disease.

Material And Methods: Based on the focused questions, electronic and manual searches were conducted for human, animal and cellular studies on the above topics.

Results: Papers fulfilling the inclusion criteria were selected and reviews were written and reviewed and corrected before the academy meeting to produce consensus statements.

Conclusion: The following consensus statements were produced. PMNs are important in the pathophysiology of periodontal disease but there is limited evidence on their much quoted destructive potential. Cytokine networks are enormously complex and we are really at the beginning of understanding their role in the disease process. RA has both similarities and marked differences to periodontal disease although the existing utilization of anti-cytokine therapies and other molecules in its treatment may have importance in periodontal disease therapy. Biomarkers for periodontal disease have yet to be completely defined but the ratio of receptor activator of NF-κB ligand to osteoprotegerin appears to be a biomarker test with utility for detecting bone destruction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1600-051X.2010.01682.xDOI Listing
March 2011

Host-derived diagnostic markers related to soft tissue destruction and bone degradation in periodontitis.

J Clin Periodontol 2011 Mar;38 Suppl 11:85-105

Department of Periodontology, School of Dentistry, Ege University, Izmir, Turkey.

Background: A major challenge in clinical periodontics is to find a reliable molecular marker of periodontal tissue destruction with high sensitivity, specificity and utility.

Objectives: The aim of this systematic review is to evaluate available literature on 'the utility of molecular markers of soft and hard periodontal tissue destruction'.

Materials And Methods: Based on the focused question, 'What is the utility of molecular markers of soft and hard periodontal tissue destruction', an electronic and manual search was conducted for human studies presenting clinical data for the potential of molecular markers of tissue destruction in biofluids; gingival crevicular fluid (GCF), saliva, and serum.

Results: Papers fulfilling the inclusion criteria were selected. All relevant data from the selected papers were extracted and recorded in separate tables for molecules in GCF, saliva, and serum.

Conclusion: Within the defined limits of the Problem/Population, Intervention, Comparison, Outcome, the present analysis reveals that (a) no single or combination of markers exists that can disclose periodontal tissue destruction adequately; (b) while the most fruitful source of biomarkers for periodontal destruction appears to be in molecules tightly related to bone and soft tissue destruction, this remains to be objectively demonstrated. Currently, clinical measurements are still the most reliable.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1600-051X.2010.01670.xDOI Listing
March 2011

The role of glycogen synthase kinase 3 in regulating IFN-β-mediated IL-10 production.

J Immunol 2011 Jan 15;186(2):675-84. Epub 2010 Dec 15.

Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, KY 40202, USA.

The ability of IFN-β to induce IL-10 production from innate immune cells is important for its anti-inflammatory properties and is believed to contribute to its therapeutic value in treating multiple sclerosis patients. In this study, we identified that IFN-β stimulates IL-10 production by activating the JAK1- and PI3K-signaling pathways. JAK1 activity was required for IFN-β to activate PI3K and Akt1 that resulted in repression of glycogen synthase kinase 3 (GSK3)-β activity. IFN-β-mediated suppression of GSK3-β promoted IL-10, because IL-10 production by IFN-β-stimulated dendritic cells (DC) expressing an active GSK3-β knockin was severely reduced, whereas pharmacological or genetic inhibition of GSK3-β augmented IL-10 production. IFN-β increased the phosphorylated levels of CREB and STAT3 but only CREB levels were affected by PI3K. Also, a knockdown in CREB, but not STAT3, affected the capacity of IFN-β to induce IL-10 from DC. IL-10 production by IFN-β-stimulated DC was shown to suppress IFN-γ and IL-17 production by myelin oligodendrocyte glycoprotein-specific CD4(+) T cells, and this IL-10-dependent anti-inflammatory effect was enhanced by directly targeting GSK3 in DC. These findings highlight how IFN-β induces IL-10 production and the importance that IL-10 plays in its anti-inflammatory properties, as well as identify a therapeutic target that could be used to increase the IL-10-dependent anti-inflammatory properties of IFN-β.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4049/jimmunol.1001473DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3606930PMC
January 2011

Gingival crevicular fluid IL-6, tPA, PAI-2, albumin levels following initial periodontal treatment in chronic periodontitis patients with or without type 2 diabetes.

Inflamm Res 2011 Feb 17;60(2):143-51. Epub 2010 Sep 17.

Department of Periodontology, School of Dentistry, Ege University, 35100 Bornova, İzmir, Turkey.

Objectives: To evaluate initial periodontal treatment effects on gingival crevicular fluid (GCF) interleukin-6 (IL-6), tissue-type plasminogen activator (tPA), plasminogen activator inhibitor-2 (PAI-2), albumin levels in type 2 diabetic patients.

Design And Methods: GCF samples were collected from 20 type 2 diabetic, 22 non-diabetic non-smokers all with chronic periodontitis at baseline, 1-, 3-months following initial periodontal treatment. Biochemical analysis was performed by ELISA. Data were tested by Mann-Whitney U, Wilcoxon tests.

Results: The total amounts of albumin, IL-6, tPA, PAI-2 decreased significantly in diabetics after treatment (1- and 3-months) whereas, only PAI-2 decreased in non-diabetic group at 3-months (p < 0.05). There were statistically significant differences between the diabetics and non-diabetics at all time points for albumin, PAI-2 and at 1-, 3-months for GCF volume (p < 0.050) but only at baseline for IL-6 (p < 0.050).

Conclusion: Present data suggest clinical improvements are less apparent in diabetic chronic periodontitis patients as reflected by disease markers in GCF and by an increase in concentrations of inflammatory proteins IL-6, tPA, and PAI-2 in GCF of this patient group following initial periodontal treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00011-010-0248-7DOI Listing
February 2011

Mammalian target of rapamycin (mTOR) regulates TLR3 induced cytokines in human oral keratinocytes.

Mol Immunol 2010 Nov-Dec;48(1-3):294-304. Epub 2010 Aug 21.

Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 South 40th Street, Philadelphia, PA 19104, USA.

Recent studies implicate the mammalian target of rapamycin (mTOR) pathway in the control of inflammatory responses following Toll-like receptor (TLR) stimulation in myeloid cells but its role in non-myeloid cells such as human keratinocytes is unknown. Here we show that TLR3 signaling can induce robust cytokine secretion including interleukin 1 beta (IL-1β), tumor necrosis factor alpha (TNFα), IL-12p70 and interferon beta (IFN-β), and our data reveal for the first time that inhibiting mTOR with rapamycin, suppresses these TLR3 induced responses but actually enhances bioactive IL-12p70 production in human oral keratinocytes. Rapamycin inhibited the phosphorylation of the 70-kDa ribosomal protein S6 kinase (p70S6K) and the 4E binding protein 1 (4EBP-1), and suppressed the mitogen activated protein kinase (MAPK) pathway by decreasing phosphorylation of c-Jun N-terminal kinase (JNK). We also show that TLR3 induces interferon regulatory factor 3 (IRF3) activation by Akt via an mTOR-p70S6K-4EBP1 pathway. Furthermore, we provide evidence that Poly I:C induced expression of IL-1β, TNFα, IL-12p70 and IFN-β was blocked by JNK inhibitor SP600125. TLR3 preferentially phosphorylated IKKα through mTOR to activate nuclear factor kappa beta (NF-κB) in human oral keratinocytes. Taken together, these data demonstrate p70S6K, p4EBP1, JNK, NF-κB and IRF3 are involved in the regulation of inflammatory mediators by TLR3 via the mTOR pathway. mTOR is a novel pathway modulating TLR3 induced inflammatory and antiviral responses in human oral keratinocytes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.molimm.2010.07.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4372152PMC
January 2011

Sphingosine kinase-1 is required for toll mediated beta-defensin 2 induction in human oral keratinocytes.

PLoS One 2010 Jul 9;5(7):e11512. Epub 2010 Jul 9.

Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

Background: Host defense against invading pathogens is triggered by various receptors including toll-like receptors (TLRs). Activation of TLRs is a pivotal step in the initiation of innate, inflammatory, and antimicrobial defense mechanisms. Human beta-defensin 2 (HBD-2) is a cationic antimicrobial peptide secreted upon gram-negative bacterial perturbation in many cells. Stimulation of various TLRs has been shown to induce HBD-2 in oral keratinocytes, yet the underlying cellular mechanisms of this induction are poorly understood.

Principal Findings: Here we demonstrate that HBD-2 induction is mediated by the Sphingosine kinase-1 (Sphk-1) and augmented by the inhibition of Glycogen Synthase Kinase-3beta (GSK-3beta) via the Phosphoinositide 3-kinase (PI3K) dependent pathway. HBD-2 secretion was dose dependently inhibited by a pharmacological inhibitor of Sphk-1. Interestingly, inhibition of GSK-3beta by SB 216763 or by RNA interference, augmented HBD-2 induction. Overexpression of Sphk-1 with concomitant inhibition of GSK-3beta enhanced the induction of beta-defensin-2 in oral keratinocytes. Ectopic expression of constitutively active GSK-3beta (S9A) abrogated HBD-2 whereas kinase inactive GSK-3beta (R85A) induced higher amounts of HBD-2.

Conclusions/significance: These data implicate Sphk-1 in HBD-2 regulation in oral keratinocytes which also involves the activation of PI3K, AKT, GSK-3beta and ERK 1/2. Thus we reveal the intricate relationship and pathways of toll-signaling molecules regulating HBD-2 which may have therapeutic potential.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0011512PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2901390PMC
July 2010

Nonsurgical mechanical treatment strategies for periodontal disease.

Dent Clin North Am 2010 Jan;54(1):1-12

Dental School, Department of Preventive Dentistry, Periodontology and Biology of Implants, Aristotle University of Thessaloniki, University Campus, 54124 Greece.

The comparison of the efficacy of surgical and nonsurgical procedures revealed that scaling and root planing alone or in combination with flap procedures are effective methods for the treatment of chronic periodontitis. Also, the consistent message is that in treating deep pockets, open-flap debridement results in greater probing pocket depth reduction and clinical attachment gain than nonsurgical modalities. Nonsurgical modalities in shallower pockets consistently involve less post-therapy recession and are clearly recognized as being more conservative. Research is still needed on the clinical benefit of the granulation tissue removal that is a feature of periodontal surgical therapy and, to a lesser extent, occurs through indirect trauma in nonsurgical therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cden.2009.08.006DOI Listing
January 2010