Significant expression of FURIN and ACE2 on oral epithelial cells may facilitate the efficiency of SARS-CoV-2 entry

AbstractBackgroundLeading to a sustained epidemic spread with >2,000,000 confirmed human infections, including >100,000 deaths, COVID-19 was caused by SARS-CoV-2 and resulted in acute respiratory distress syndrome (ARDS) and sepsis, which brought more challenges to the patient’s treatment. The S-glycoprotein, which recognized as the key factor for the entry of SARS-CoV-2 into the cell, contains two functional domains: an ACE2 receptor binding domain and a second domain necessary for fusion of the coronavirus and cell membranes. FURIN activity, exposes the binding and fusion domains, is essential for the zoonotic transmission of SARS-CoV-2. Moreover, it has been reported that ACE2 is likely to be the receptor for SARS-CoV-2. In addition, FURIN enzyme and ACE2 receptor were expressed in airway epithelia, cardiac tissue, and enteric canals, which considered as the potential target organ of the virus. However, report about the expression of FURIN and ACE2 in oral tissues was limited.MethodsIn order to investigate the potential infective channel of new coronavirus in oral cavity, we analyze the expression of ACE2 and FURIN that mediate the new coronavirus entry into host cells in oral mucosa using the public single-cell sequence datasets. Furthermore, immunohistochemical staining experiment was performed to confirm the expression of ACE2 and FURIN in the protein level.ResultsThe bioinformatics results indicated the differential expression of ACE2 and FURIN on epithelial cells of different oral mucosal tissues and the proportion of FURIN-positive cells was obviously higher than that of ACE2-positive cells. IHC experiments revealed that both the ACE2-positive and FURIN-positive cells in the target tissues were mainly positioned in the epithelial layers, partly expressed in fibroblasts, which further confirm the bioinformatics results.ConclusionsBased on these findings, we speculated that SARS-CoV-2 could effectively invade oral mucosal cells though two possible routes: binding to the ACE2 receptor and fusion with cell membrane activated by FURIN protease. Our results indicated that oral mucosa tissues are susceptible to SARS-CoV-2, which provides valuable information for virus-prevention strategy in clinical care as well as daily life.

Download Full-text

ACE2 and Furin Expressions in Oral Epithelial Cells Possibly Facilitate COVID-19 Infection via Respiratory and Fecal–Oral Routes

Frontiers in Medicine ◽

10.3389/fmed.2020.580796 ◽

2020 ◽

Vol 7 ◽

Author(s):

Mei Zhong ◽

Bingpeng Lin ◽

Janak L. Pathak ◽

Hongbin Gao ◽

Andrew J. Young ◽

...

Keyword(s):

Epithelial Cells ◽

Oral Mucosa ◽

Cardiac Tissue ◽

Expression Patterns ◽

Mrna Level ◽

Cell Types ◽

Mucosal Cells ◽

Key Factor ◽

Epithelial Layers ◽

Different Cell Types

Background: Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that mainly transfers from human to human via respiratory and gastrointestinal routes. The S-glycoprotein in the virus is the key factor for the entry of SARS-CoV-2 into the cell, which contains two functional domains: S1 is an angiotensin-converting enzyme 2 (ACE2) receptor binding domain, and S2 is necessary for fusion of the coronavirus and cell membranes. Moreover, it has been reported that ACE2 is likely to be the receptor for SARS-CoV-2. In addition, mRNA level expression of Furin enzyme and ACE2 receptor had been reported in airway epithelia, cardiac tissue, and enteric canals. However, the expression patterns of ACE2 and Furin in different cell types of oral tissues are still unclear.Methods: In order to investigate the potential infective channel of the new coronavirus via the oropharyngeal cavity, we analyze the expression of ACE2 and Furin in human oral mucosa using the public single-cell sequence datasets. Furthermore, immunohistochemistry was performed in mucosal tissue from different oral anatomical sites to confirm the expression of ACE2 and Furin at the protein level.Results: The bioinformatics results indicated the differential expression of ACE2 and Furin on epithelial cells from different oral anatomical sites. Immunohistochemistry results revealed that both the ACE2-positive and Furin-positive cells in the target tissues were mainly positioned in the epithelial layers, partly expressed in fibroblasts, further confirming the bioinformatics results.Conclusions: Based on these findings, we speculated that SARS-CoV-2 could invade oral mucosal cells through two possible routes: binding to the ACE2 receptor and fusion with cell membrane activated by Furin protease. Our results indicated that oral mucosa tissues are susceptible to SARS-CoV-2 that could facilitate COVID-19 infection via respiratory and fecal–oral routes.

Download Full-text

Expression of toll-like and adhesive receptors on epithelial cells of the oral mucosa in periodontitis

Russian Clinical Laboratory Diagnostics ◽

10.18821/0869-2084-2020-65-10-645-648 ◽

2020 ◽

Vol 65 (10) ◽

pp. 645-648

Author(s):

O. A. Lukova ◽

M. I. Zaslavskaya ◽

T. V. Makhrova ◽

V. S. Kropotov ◽

E. V. Kitaeva

Keyword(s):

Epithelial Cells ◽

Oral Mucosa ◽

Functional State ◽

Chronic Periodontitis ◽

Inflammatory Process ◽

Microbial Colonization ◽

Oral Microbiota ◽

Flow Cytofluorometry ◽

Buccal Epithelial Cells ◽

Mucosal Cells

The expression of toll-like and adhesive receptors on epithelial cells of the oral mucosa changes in different pathological conditions, both local and systemic levels, in particular, in chronic periodontitis. The long-term presence of periodontal pathogenic microorganisms in the gingival furrow stimulates and supports the inflammatory process. The interaction of periodontal pathogens with epithelial cells of the oral mucosa is the first stage of the development of periodontitis. The pathological process affects the function of epithelial cells, in particular their ability to interact with representatives of microbiocenosis. Therefore, the natural colonization of normal oral microbiota on buccal epitheliocytes, reflecting the ability of epithelial cells to microbial adhesion, is a sensitive indicator of various destabilizing processes. Determining the level of expression of toll-like TLR2 and TLR4 receptors on epithelial cells also allows us to assess the functional state of cells and the severity of the inflammatory process at the level of the oral mucosa, in particular, in chronic periodontitis. In this paper, we studied the receptor-dependent reactions of buccal epithelial cells in chronic periodontitis using flow cytofluorometry and by determining the level of natural (microbial) colonization. The authors also compared these methods for determining the functional state of mucosal cells in chronic periodontitis. The results showed that in patients with periodontitis, the activity of receptors involved in adhesive reactions with the oral microbiota changed slightly and was little higher than in healthy donors. At the same time, the expression of TLRs on epithelial cells in periodontitis changed significantly. Thus, the percentage of cells expressing TLR2 significantly increased, while TLR4 decreased. Concurrently, the percentage of mucosal cells that do not have TLRs increased significantly in oral pathology. Thus, the study of TLR2 - and TLR4-expression on buccal epithelial cells is a more representative test in assessing the severity of the inflammatory process in chronic periodontitis than determining the level of natural colonization.

Download Full-text

Mucosal Tissue Invasion by Candida albicans Is Associated with E-Cadherin Degradation, Mediated by Transcription Factor Rim101p and Protease Sap5p

Infection and Immunity ◽

10.1128/iai.00054-07 ◽

2007 ◽

Vol 75 (5) ◽

pp. 2126-2135 ◽

Cited By ~ 127

Author(s):

C. C. Villar ◽

H. Kashleva ◽

C. J. Nobile ◽

A. P. Mitchell ◽

A. Dongari-Bagtzoglou

Keyword(s):

Candida Albicans ◽

Epithelial Cells ◽

Oral Mucosa ◽

Cell Junctions ◽

Fungal Virulence ◽

Oral Epithelial Cells ◽

Tissue Invasion ◽

Mucosal Tissues ◽

Oral Epithelial ◽

E Cadherin

ABSTRACT The ability of Candida albicans to invade mucosal tissues is a major virulence determinant of this organism; however, the mechanism of invasion is not understood in detail. Proteolytic breakdown of E-cadherin, the major protein in epithelial cell junctions, has been proposed as a mechanism of invasion of certain bacteria in the oral mucosa. The objectives of this study were (i) to assess whether C. albicans degrades E-cadherin expressed by oral epithelial cells in vitro; (ii) to compare the abilities of strains with different invasive potentials to degrade this protein; and (iii) to investigate fungal virulence factors responsible for E-cadherin degradation. We found that while E-cadherin gene expression was not altered, E-cadherin was proteolytically degraded during the interaction of oral epithelial cells with C. albicans. Moreover, C. albicans-mediated degradation of E-cadherin was completely inhibited in the presence of protease inhibitors. Using a three-dimensional model of the human oral mucosa, we found that E-cadherin was degraded in localized areas of tissue invasion by C. albicans. An invasion-deficient rim101 −/rim101 − strain was deficient in degradation of E-cadherin, and this finding suggested that proteases may depend on Rim101p for expression. Indeed, reverse transcription-PCR data indicated that expression of the SAP4, SAP5, and SAP6 genes is severely reduced in the rim101 −/rim101 − mutant. These SAP genes are functional Rim101p targets, because engineered expression of SAP5 in the rim101 −/rim101 − strain restored E-cadherin degradation and invasion in the mucosal model. Our data support the hypothesis that there is a mechanism by which C. albicans invades mucosal tissues by promoting the proteolytic degradation of E-cadherin in epithelial adherens junctions.

Download Full-text

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.

Download Full-text

Epithelial cells from oral mucosa: How to cultivate them?

Cytotechnology ◽

10.1007/s10616-016-9950-9 ◽

2016 ◽

Vol 68 (5) ◽

pp. 2105-2114 ◽

Cited By ~ 2

Author(s):

F. B. Russo ◽

G. C. Pignatari ◽

I. R. Fernandes ◽

J. L. R. M. Dias ◽

P. C. B. Beltrão-Braga

Keyword(s):

Epithelial Cells ◽

Oral Mucosa

Download Full-text

Motility of endodermal epithelial cells plays a major role in reorganizing the two epithelial layers in Hydra

Mechanisms of Development ◽

10.1016/j.mod.2004.08.004 ◽

2005 ◽

Vol 122 (1) ◽

pp. 109-122 ◽

Cited By ~ 16

Author(s):

Yasuharu Takaku ◽

Takahiko Hariyama ◽

Toshitaka Fujisawa

Keyword(s):

Epithelial Cells ◽

Epithelial Layers

Download Full-text

Host DNA Repair Proteins in Response toPseudomonas aeruginosain Lung Epithelial Cells and in Mice

Infection and Immunity ◽

10.1128/iai.00815-10 ◽

2010 ◽

Vol 79 (1) ◽

pp. 75-87 ◽

Cited By ~ 35

Author(s):

Min Wu ◽

Huang Huang ◽

Weidong Zhang ◽

Shibichakravarthy Kannan ◽

Andrew Weaver ◽

...

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Epithelial Cells ◽

Critical Role ◽

Lung Epithelial Cells ◽

Host Cells ◽

Myeloperoxidase Activity ◽

Gram Negative ◽

Lung Epithelial ◽

Dna Repair Proteins

ABSTRACTAlthough DNA repair proteins in bacteria are critical for pathogens' genome stability and for subverting the host defense, the role of host DNA repair proteins in response to bacterial infection is poorly defined. Here, we demonstrate, for the first time, that infection with the Gram-negative bacteriumPseudomonas aeruginosasignificantly altered the expression and enzymatic activity of 8-oxoguanine DNA glycosylase (OGG1) in lung epithelial cells. Downregulation of OGG1 by a small interfering RNA strategy resulted in severe DNA damage and cell death. In addition, acetylation of OGG1 is required for host responses to bacterial genotoxicity, as mutations of OGG1 acetylation sites increased Cockayne syndrome group B (CSB) protein expression. These results also indicate that CSB may be involved in DNA repair activity during infection. Furthermore, OGG1 knockout mice exhibited increased lung injury after infection withP. aeruginosa, as demonstrated by higher myeloperoxidase activity and lipid peroxidation. Together, our studies indicate thatP. aeruginosainfection induces significant DNA damage in host cells and that DNA repair proteins play a critical role in the host response toP. aeruginosainfection, serving as promising targets for the treatment of this condition and perhaps more broadly Gram-negative bacterial infections.

Download Full-text

Povidone-Iodine Attenuates Viral Replication in Ocular Cells: Implications for Ocular Transmission of RNA Viruses

Biomolecules ◽

10.3390/biom11050753 ◽

2021 ◽

Vol 11 (5) ◽

pp. 753

Author(s):

Sneha Singh ◽

Onkar B. Sawant ◽

Shahzad I. Mian ◽

Ashok Kumar

Keyword(s):

Epithelial Cells ◽

Viral Replication ◽

Povidone Iodine ◽

Rna Viruses ◽

Retinal Pigment ◽

Retinal Pigment Epithelial Cells ◽

Host Cells ◽

Eye Banking ◽

Antiviral Effects ◽

Infected Cells

Several RNA viruses, including SARS-CoV-2, can infect or use the eye as an entry portal to cause ocular or systemic diseases. Povidone-Iodine (PVP-I) is routinely used during ocular surgeries and eye banking as a cost-effective disinfectant due to its broad-spectrum antimicrobial activity, including against viruses. However, whether PVP-I can exert antiviral activities in virus-infected cells remains elusive. In this study, using Zika (ZIKV) and Chikungunya (CHIKV) virus infection of human corneal and retinal pigment epithelial cells, we report antiviral mechanisms of PVP-I. Our data showed that PVP-I, even at the lowest concentration (0.01%), drastically reduced viral replication in corneal and retinal cells without causing cellular toxicity. Antiviral effects of PVP-I against ZIKV and CHIKV were mediated by direct viral inactivation, thus attenuating the ability of the virus to infect host cells. Moreover, one-minute PVP-I exposure of infected ocular cells drastically reduced viral replication and the production of infectious progeny virions. Furthermore, viral-induced (CHIKV) expression of inflammatory genes (TNF-α, IL-6, IL-8, and IL1β) were markedly reduced in PVP-I treated corneal epithelial cells. Together, our results demonstrate potent antiviral effects of PVP-I against ZIKV and CHIKV infection of ocular cells. Thus, a low dose of PVP-I can be used during tissue harvesting for corneal transplants to prevent potential transmission of RNA viruses via infected cells.

Download Full-text

Evaluation of the Role of Staphylococci in the Pathomechanism of Conjunctivitis

10.21203/rs.3.rs-191872/v1 ◽

2021 ◽

Author(s):

Ewa Jasińska ◽

Agnieszka Bogut ◽

Agnieszka Magryś ◽

Alina Olender

Keyword(s):

Antibiotic Resistance ◽

Epithelial Cells ◽

Biofilm Formation ◽

Methicillin Resistance ◽

Microtiter Plate ◽

Host Cells ◽

Diffusion Method ◽

Microtiter Plate Assay ◽

Low Prevalence

Abstract Purpose: Determination of the association between ica genes and phenotypic biofilm formation in staphylococcal isolates involved in conjunctivitis, their antibiotic resistance as well as detection of selected virulence characteristics: adhesion to epithelial cells and in vitro cytotoxicity.Methods: The study included 26 Staphylococcus aureus (SA) and 26 Staphylococcus epidermidis (SE) isolates. The presence of icaAD genes and ica operon was determined by the PCR assay. Phenotypic biofilm formation was verified using the microtiter plate assay. Antibiotic resistance was performed using the disc diffusion method. Staphylococcal ability to attach to host cells was assessed by flow cytometry. Cytotoxicity on epithelial cells was evaluated by LDH assay.Results: The ica genes were detected in 26.9% of SE and in 42.3% of SA isolates. Only 15.3% of isolates (SE) were positive for both the icaAD and the ica operon. Phenotypically, 19.2% of SE isolates were strong biofilm producers, among which three were both icaAD- and ica operon-positive. 26.9% of SA isolates were strong biofilm producers. Methicillin resistance (MR) was detected in 34.6% of SE and 26.9% of SA isolates. 75% of MR isolates were multidrug resistant. SA isolates adhered to host cells more extensively than SE. SA isolates released higher level of LDH than SE.Conclusions: Adherence abilities were commonly observed in staphylococci associated with conjunctivitis. However, low prevalence of isolates positive for a complete and functional ica locus and low prevalence of strong biofilm producers was detected. SA adhered to a greater extent to eukaryotic cells than SE and were more cytotoxic.

Download Full-text

Interactions Between Salmonella Typhimurium, Enteropathogenic Escherichia Coli (EPEC), and Host Epithelial Cells

Advances in Dental Research ◽

10.1177/08959374950090010601 ◽

1995 ◽

Vol 9 (1) ◽

pp. 31-36 ◽

Cited By ~ 5

Author(s):

B.B. Finlay

Keyword(s):

Escherichia Coli ◽

Epithelial Cells ◽

Salmonella Typhimurium ◽

Host Cell ◽

Inositol Phosphate ◽

Enteric Pathogens ◽

Host Protein ◽

Host Cells ◽

Enteropathogenic Escherichia Coli ◽

Sequence Of Events

The interactions that occur between pathogenic micro-organisms and their host cells are complex and intimate. We have used two enteric pathogens, Salmonella typhimurium and enteropathogenic Escherichia coli (EPEC), to examine the interactions that occur between these organisms and epithelial cells. Although these are enteric pathogens, the knowledge and techniques developed from these systems may be applied to the study of dental pathogens. Both S. typhimurium and EPEC disrupt epithelial monolayer integrity, although by different mechanisms. Both pathogens cause loss of microvilli and re-arrangement of the underlying host cytoskeleton. Despite these similarities, both organisms send different signals into the host cell. EPEC signal transduction involves generation of intracellular calcium and inositol phosphate fluxes, and activation of host tyrosine kinases that results in tyrosine phosphorylation of a 90-kDa host protein. Bacterial mutants have been identifed that are deficient in signaling to the host. We propose a sequence of events that occur when EPEC interacts with epithelial cells. Once inside a host cell, S. typhimurium remains within a vacuole. To define some of the parameters of the intracellular environment, we constructed genetic fusions of known genes with lacZ, and used these fusions as reporter probes of the intracellular vacuolar environment. We have also begun to examine the bacterial and host cell factors necessary for S. typhimurium to multiply within epithelial cells. We found that this organism triggers the formation of novel tubular lysosomes, and these structures are linked with intracellular replication.

Download Full-text