E-Cigarette Vapor Induces an Apoptotic Response in Human Gingival Epithelial Cells Through the Caspase-3 Pathway

Apoptosis is thought to contribute to the progression of periodontitis. It has been suggested that the apoptosis of epithelial cells may contribute to the loss of epithelial barrier function. Smad2, a downstream signaling molecule of TGF-β receptors (TGF-βRs), is critically involved in apoptosis in several cell types. However, the relationship between smad2 and bacteria-induced apoptosis has not yet been elucidated. It is possible that the regulation of apoptosis induced by periodontopathic bacteria may lead to novel preventive therapies for periodontitis. Therefore, in the present study, we investigated the involvement of smad2 phosphorylation in apoptosis of human gingival epithelial cells induced by Aggregatibacter actinomycetemcomitans ( Aa). Aa apparently induced the phosphorylation of smad2 in primary human gingival epithelial cells (HGECs) or the human gingival epithelial cell line, OBA9 cells. In addition, Aa induced phosphorylation of the serine residue of the TGF-β type I receptor (TGF-βRI) in OBA9 cells. SB431542 (a TGF-βRI inhibitor) and siRNA transfection for TGF-βRI, which reduced both TGF-βRI mRNA and protein levels, markedly attenuated the Aa-induced phosphorylation of smad2. Furthermore, the disruption of TGF-βRI signaling cascade by SB431542 and siRNA transfection for TGF-βRI abrogated the activation of cleaved caspase-3 expression and repressed apoptosis in OBA9 cells treated with Aa. Thus, Aa induced apoptosis in gingival epithelial cells by activating the TGF-βRI-smad2-caspase-3 signaling pathway. The results of the present study may suggest that the periodontopathic bacteria, Aa, activates the TGF-βR/smad2 signaling pathway in human gingival epithelial cells and induces apoptosis in epithelial cells, which may lead to new therapeutic strategies that modulate the initiation of periodontitis.

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Porphyromonas gingivalis enhances FasL expression via up-regulation of NFκB-mediated gene transcription and induces apoptotic cell death in human gingival epithelial cells

Microbiology ◽

10.1099/mic.0.28472-0 ◽

2006 ◽

Vol 152 (3) ◽

pp. 797-806 ◽

Cited By ~ 40

Author(s):

Suzana Brozovic ◽

Rashmita Sahoo ◽

Shirish Barve ◽

Hideki Shiba ◽

Silvia Uriarte ◽

...

Keyword(s):

Cell Death ◽

Epithelial Cells ◽

Porphyromonas Gingivalis ◽

Caspase 3 ◽

Apoptotic Cell ◽

Apoptotic Cell Death ◽

Luciferase Assay ◽

Caspase 8 ◽

Gingival Epithelial Cells ◽

Human Gingival Epithelial Cells

The interaction between epithelial cells and micro-organisms is often a crucial initiating event in infectious diseases. Infection with Porphyromonas gingivalis, a Gram-negative anaerobe, is strongly associated with severe periodontal disease. This bacterium possesses an array of virulence factors, some of which can induce apoptosis. The tumour necrosis factor (TNF) receptor family is involved in the regulation of cellular homeostasis, cell surface molecules involved in phagocytosis, Fas ligand (L) expression and activation of the caspase cascade resulting in DNA fragmentation and cell blebbing. The current study examined the role of nuclear factor-κB (NFκB) in FasL-mediated apoptotic cell death in primary human gingival epithelial cells (HGEC) induced by heat-killed P. gingivalis, probably through TLR signalling pathways. A marked up-regulation of TLR2 and Fas–FasL was detected in HGEC stimulated with P. gingivalis. Activation of NFκB by P. gingivalis in HGEC was demonstrated by an NFκB promoter luciferase assay as well as by phosphorylation of p65 as detected by Western blotting. Activation of cleaved caspase-3 and caspase-8 resulted in apoptotic cell death of HGEC. The survival proteins c-IAP-1/c-IAP-2 were decreased in HGEC exposed to P. gingivalis. HGEC apoptosis induced by P. gingivalis was inhibited by an anti-human FasL monoclonal antibody. Blockade of NFκB by helenalin resulted in down-regulation of FasL whereas a caspase-8 inhibitor did not decrease FasL. Taken together, these studies show that P. gingivalis can induce epithelial cell apoptosis through Fas–FasL up-regulation and activation of caspase-3 and caspase-8.

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Cigarette Smoke Stimulates SARS-CoV-2 Internalization by Activating AhR and Increasing ACE2 Expression in Human Gingival Epithelial Cells

International Journal of Molecular Sciences ◽

10.3390/ijms22147669 ◽

2021 ◽

Vol 22 (14) ◽

pp. 7669

Author(s):

Cassio Luiz Coutinho Almeida-da-Silva ◽

Harmony Matshik Dakafay ◽

Kaitlyn Liu ◽

David M. Ojcius

Keyword(s):

Epithelial Cells ◽

Oral Cavity ◽

Cigarette Smoke ◽

Large Body ◽

Receptor Expression ◽

Host Cells ◽

Dependent Manner ◽

Gingival Epithelial Cells ◽

Human Gingival Epithelial Cells ◽

Oral Cells

A large body of evidence shows the harmful effects of cigarette smoke to oral and systemic health. More recently, a link between smoking and susceptibility to coronavirus disease 2019 (COVID-19) was proposed. COVID-19 is due to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which uses the receptor ACE2 and the protease TMPRSS2 for entry into host cells, thereby infecting cells of the respiratory tract and the oral cavity. Here, we examined the effects of cigarette smoke on the expression of SARS-CoV-2 receptors and infection in human gingival epithelial cells (GECs). We found that cigarette smoke condensates (CSC) upregulated ACE2 and TMPRSS2 expression in GECs, and that CSC activated aryl hydrocarbon receptor (AhR) signaling in the oral cells. ACE2 was known to mediate SARS-CoV-2 internalization, and we demonstrate that CSC treatment potentiated the internalization of SARS-CoV-2 pseudovirus in GECs in an AhR-dependent manner. AhR depletion using small interference RNA decreased SARS-CoV-2 pseudovirus internalization in CSC-treated GECs compared with control GECs. Our study reveals that cigarette smoke upregulates SARS-CoV-2 receptor expression and infection in oral cells. Understanding the mechanisms involved in SARS-CoV-2 infection in cells of the oral cavity may suggest therapeutic interventions for preventing viral infection and transmission.

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Pro-inflammatory cytokine responses in human gingival epithelial cells after stimulation with cell wall extract of Aggregatibacter actinomycetemcomitans subtypes

Anaerobe ◽

10.1016/j.anaerobe.2017.08.001 ◽

2017 ◽

Vol 48 ◽

pp. 103-109 ◽

Cited By ~ 5

Author(s):

Nuntiya Pahumunto ◽

Pareena Chotjumlong ◽

Anupong Makeudom ◽

Suttichai Krisanaprakornkit ◽

Gunnar Dahlen ◽

...

Keyword(s):

Cell Wall ◽

Epithelial Cells ◽

Inflammatory Cytokine ◽

Aggregatibacter Actinomycetemcomitans ◽

Cytokine Responses ◽

Gingival Epithelial Cells ◽

Cell Wall Extract ◽

Human Gingival Epithelial Cells

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Identification of Porphyromonas gingivalis Genes Specifically Expressed in Human Gingival Epithelial Cells by Using Differential Display Reverse Transcription-PCR

Infection and Immunity ◽

10.1128/iai.72.7.3752-3758.2004 ◽

2004 ◽

Vol 72 (7) ◽

pp. 3752-3758 ◽

Cited By ~ 34

Author(s):

Yoonsuk Park ◽

Özlem Yilmaz ◽

Il-Young Jung ◽

Richard J. Lamont

Keyword(s):

Epithelial Cells ◽

Porphyromonas Gingivalis ◽

Abc Transporter ◽

Differential Display ◽

Molecular Mechanisms ◽

Gene Products ◽

Reverse Transcription Pcr ◽

Gingival Epithelial Cells ◽

Insertional Inactivation ◽

Human Gingival Epithelial Cells

ABSTRACT Porphyromonas gingivalis, one of the causative agents of adult periodontitis, can invade and survive within host epithelial cells. The molecular mechanisms by which P. gingivalis induces uptake and adapts to an intracellular environment are not fully understood. In this study, we have investigated the genetic responses of P. gingivalis internalized within human gingival epithelial cells (GECs) in order to identify factors involved in invasion and survival. We compared the differential display of arbitrarily PCR-amplified gene transcripts in P. gingivalis recovered from GECs with the display of transcripts in P. gingivalis control cultures. Over 20 potential differentially expressed transcripts were identified. Among these, pepO, encoding an endopeptidase, and genes encoding an ATP-binding cassette (ABC) transporter and a cation-transporting ATPase were upregulated in GECs. To investigate the functionality of these gene products, mutants were generated by insertional inactivation. Compared to the parental strain, mutants of each gene showed a significant reduction in their invasion capabilities. In addition, GEC cytoskeletal responses to the mutants were distinct from those induced by the parent. In contrast, adhesion of the mutant strains to GECs was not affected by lack of expression of the gene products. These results suggest that PepO, a cation-transporting ATPase, and an ABC transporter are required for the intracellular lifestyle of P. gingivalis.

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