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1.
Intracellular Cl- Regulation of Ciliary Beating in Ciliated Human Nasal Epithelial Cells: Frequency and Distance of Ciliary Beating Observed by High-Speed Video Microscopy.
Yasuda, M, Inui, TA, Hirano, S, Asano, S, Okazaki, T, Inui, T, Marunaka, Y, Nakahari, T
International journal of molecular sciences. 2020;(11)
Abstract
Small inhaled particles, which are entrapped by the mucous layer that is maintained by mucous secretion via mucin exocytosis and fluid secretion, are removed from the nasal cavity by beating cilia. The functional activities of beating cilia are assessed by their frequency and the amplitude. Nasal ciliary beating is controlled by intracellular ions (Ca2+, H+ and Cl-), and is enhanced by a decreased concentration of intracellular Cl- ([Cl-]i) in ciliated human nasal epithelial cells (cHNECs) in primary culture, which increases the ciliary beat amplitude. A novel method to measure both ciliary beat frequency (CBF) and ciliary beat distance (CBD, an index of ciliary beat amplitude) in cHNECs has been developed using high-speed video microscopy, which revealed that a decrease in [Cl-]i increased CBD, but not CBF, and an increase in [Cl-]i decreased both CBD and CBF. Thus, [Cl-]i inhibits ciliary beating in cHNECs, suggesting that axonemal structures controlling CBD and CBF may have Cl- sensors and be regulated by [Cl-]i. These observations indicate that the activation of Cl- secretion stimulates ciliary beating (increased CBD) mediated via a decrease in [Cl-]i in cHNECs. Thus, [Cl-]i is critical for controlling ciliary beating in cHNECs. This review introduces the concept of Cl- regulation of ciliary beating in cHNECs.
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2.
Effects of Short-Chain Fatty Acids on Human Oral Epithelial Cells and the Potential Impact on Periodontal Disease: A Systematic Review of In Vitro Studies.
Magrin, GL, Strauss, FJ, Benfatti, CAM, Maia, LC, Gruber, R
International journal of molecular sciences. 2020;(14)
Abstract
Short-chain fatty acids (SCFA), bacterial metabolites released from dental biofilm, are supposed to target the oral epithelium. There is, however, no consensus on how SCFA affect the oral epithelial cells. The objective of the present study was to systematically review the available in vitro evidence of the impact of SCFA on human oral epithelial cells in the context of periodontal disease. A comprehensive electronic search using five databases along with a grey literature search was performed. In vitro studies that evaluated the effects of SCFA on human oral epithelial cells were eligible for inclusion. Risk of bias was assessed by the University of Bristol's tool for assessing risk of bias in cell culture studies. Certainty in cumulative evidence was evaluated using GRADE criteria (grading of recommendations assessment, development, and evaluation). Of 3591 records identified, 10 were eligible for inclusion. A meta-analysis was not possible due to the heterogeneity between the studies. The risk of bias across the studies was considered "serious" due to the presence of methodological biases. Despite these limitations, this review showed that SCFA negatively affect the viability of oral epithelial cells by activating a series of cellular events that includes apoptosis, autophagy, and pyroptosis. SCFA impair the integrity and presumably the transmigration of leucocytes through the epithelial layer by changing junctional and adhesion protein expression, respectively. SCFA also affect the expression of chemokines and cytokines in oral epithelial cells. Future research needs to identify the underlying signaling cascades and to translate the in vitro findings into preclinical models.
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3.
Regulation of mucin 1 expression and its relationship with oral diseases.
Kashyap, B, Kullaa, AM
Archives of oral biology. 2020;:104791
Abstract
OBJECTIVE The aim of this study is to describe the polymorphic mucin 1 (MUC1), and to provide an overview of the known complex and multiple functions of MUC1 in normal oral mucosa and oral mucosal lesions in compromised situations as well as exploring the challenges associated with the heterogeneous nature of MUC1. We will review the current knowledge and provide insights into the future management possibilities of using MUC1 as a therapeutic agent. METHODS A literature search of the electronic databases included MEDLINE (1966 -December 2019) and hand searches of cross-references were undertaken using terms related to mucins, MUC1. RESULTS MUC1 is a large transmembrane glycoprotein expressed on the apical surface of most of epithelial cell surfaces. Not only is it involved in lubrication, cell surface hydration, and protection against degrading enzymes, MUC1 also promotes abnormal cellular signalling, angiogenesis, anti-adhesion and tumorigenesis. Aberrant glycosylation, overexpression, loss of apical constraint are characteristics of the transformation of a normal cell to a cancerous cell. This review summarizes studies of MUC1 expression and function with a special emphasis on oral epithelial cells in normal and abnormal conditions. In addition, current knowledge of MUC1 and unexplored areas of MUC1 are presented. CONCLUSION MUC1 is an archetypical transmembrane protein, the presence of MUC1 in ectopic regions may lead to dysregulation of certain enzymes and activation of various pathways, favouring the development of inflammatory responses and tumour formation. This review examines the potential of MUC1 in the development of future therapeutics.
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4.
Antiepithelial-Mesenchymal Transition of Herbal Active Substance in Tumor Cells via Different Signaling.
Cui, X, Lin, Q, Huang, P, Liang, Y
Oxidative medicine and cellular longevity. 2020;:9253745
Abstract
Epithelial-mesenchymal transition (EMT) is a biological process through which epithelial cells differentiate into mesenchymal cells. EMT plays an important role in embryonic development and wound healing; however, EMT also contributes to some pathological processes, such as tumor metastasis and fibrosis. EMT mechanisms, including gene mutation and transcription factor regulation, are complicated and not yet well understood. In this review, we introduce some herbal active substances that exert antitumor activity through inhibiting EMT that is induced by hypoxia, high blood glucose level, lipopolysaccharide, or other factors.
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5.
Mucosal-Associated Invariant T Cells in Tumors of Epithelial Origin.
Zumwalde, NA, Gumperz, JE
Advances in experimental medicine and biology. 2020;:63-77
Abstract
Mucosal-associated invariant T (MAIT) cells are innate T lymphocytes that circulate in blood and also reside in mucosal tissues. Blood MAIT cells are typically highly Th1-polarized, while those in mucosal tissues include both Th1- and Th17-polarized subsets. MAIT cells mount cytokine and cytolytic responses as a result of T cell receptor (TCR)-mediated recognition of microbially derived metabolites of riboflavin (vitamin B2) presented by the MR1 antigen-presenting molecule. Additionally, MAIT cells can be activated by inflammatory cytokines produced by antigen-presenting cells (APCs) that have been exposed to pathogen-associated molecular patterns (PAMPs). Since the antigenic metabolites of riboflavin recognized by MAIT cells are produced by many microorganisms, including pathogens as well as non-pathogenic colonists, the inflammatory state of the tissue may be a key feature that determines the nature of MAIT cell responses. Under normal conditions where inflammatory cytokines are not produced, MAIT cell responses to microbial metabolites may simply serve to help maintain a healthy balance between epithelial cells and microbial colonists. In contrast, in situations where inflammatory cytokines are produced (e.g., pathogenic infection or damage to epithelial tissue), MAIT cell responses may be more potently pro-inflammatory. Since chronic inflammation and microbial drivers are associated with tumorigenesis and also trigger MAIT cell responses, the nexus of MAIT cells, local microbiomes, and epithelial cells may play an important role in epithelial carcinogenesis. This chapter reviews current information about MAIT cells and epithelial tumors, where the balance of evidence suggests that enrichment of Th17-polarized MAIT cells at tumor sites associates with poor patient prognosis. Studying the role of MAIT cells and their interactions with resident microbes offers a novel view of the biology of epithelial tumor progression and may ultimately lead to new approaches to target MAIT cells clinically.
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6.
Personal level exposure and hazard potential of particulate matter during haze and non-haze periods in Singapore.
George, S, Chua, ML, ZheWei, DZ, Das, R, Bijin, VA, Connolly, JE, Lee, KP, Yung, CF, Teoh, OH, Thomas, B
Chemosphere. 2020;:125401
Abstract
Severe haze episodes originating from biomass burning are common in Southeast Asia. However, there is a paucity of data on the personal exposure and characteristics of Particulate Matter (PM) present in ambient air during haze and non-haze periods. Aims of this study were to monitor 24 h ambulatory exposure to PM among school children in Singapore; characterize haze and non-haze PM for their physicochemical properties, cytotoxicity and inflammatory potential, using bronchial epithelial cell culture model (BEAS-2B). Forty-six children had ambulatory PM exposure monitored using portable Aethalometer and their hourly activity recorded. The mean (±SE) PM exposure on a typical school day was 3343 (±174.4) ng/m3/min. Higher PM exposure was observed during haze periods and during commuting to and from the school. Characterization of PM collected showed a drastic increase in the proportion of ultrafine particle (UFP) in haze PM. These PM fraction showed higher level of sulphur, potassium and trace metals in comparison to those collected during non-haze periods. Dose dependent increases in abiotic reactive oxygen species generation, activation of NF-κB and cytotoxicity were observed for both haze and non-haze PM. Generally, haze PM induced significantly higher release of IL-6, IL-8 and TNFα by BEAS-2B cells in comparison to non-haze PM. In summary, this study provides experimental evidence for higher PM exposure during haze period which has the potential to elicit oxidative stress and pro-inflammatory cytokine release from airway epithelial cells.
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7.
Mycotoxins: Biotransformation and Bioavailability Assessment Using Caco-2 Cell Monolayer.
Tran, VN, Viktorová, J, Ruml, T
Toxins. 2020;(10)
Abstract
The determination of mycotoxins content in food is not sufficient for the prediction of their potential in vivo cytotoxicity because it does not reflect their bioavailability and mutual interactions within complex matrices, which may significantly alter the toxic effects. Moreover, many mycotoxins undergo biotransformation and metabolization during the intestinal absorption process. Biotransformation is predominantly the conversion of mycotoxins meditated by cytochrome P450 and other enzymes. This should transform the toxins to nontoxic metabolites but it may possibly result in unexpectedly high toxicity. Therefore, the verification of biotransformation and bioavailability provides valuable information to correctly interpret occurrence data and biomonitoring results. Among all of the methods available, the in vitro models using monolayer formed by epithelial cells from the human colon (Caco-2 cell) have been extensively used for evaluating the permeability, bioavailability, intestinal transport, and metabolism of toxic and biologically active compounds. Here, the strengths and limitations of both in vivo and in vitro techniques used to determine bioavailability are reviewed, along with current detailed data about biotransformation of mycotoxins. Furthermore, the molecular mechanism of mycotoxin effects is also discussed regarding the disorder of intestinal barrier integrity induced by mycotoxins.
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8.
Transcytosis of Bacillus subtilis extracellular vesicles through an in vitro intestinal epithelial cell model.
Rubio, APD, Martínez, J, Palavecino, M, Fuentes, F, López, CMS, Marcilla, A, Pérez, OE, Piuri, M
Scientific reports. 2020;(1):3120
Abstract
Bacterial EVs have been related to inter-kingdom communication between probiotic/pathogenic bacteria and their hosts. Our aim was to investigate the transcytosis process of B. subtilis EVs using an in vitro intestinal epithelial cell model. In this study, using Confocal Laser Scanning Microscopy, we report that uptake and internalization of CFSE-labeled B. subtilis EVs (115 nm ± 27 nm) by Caco-2 cells are time-dependent. To study the transcytosis process we used a transwell system and EVs were quantified in the lower chamber by Fluorescence and Nanoparticle Tracking Analysis measurements. Intact EVs are transported across a polarized cell monolayer at 60-120 min and increased after 240 min with an estimated average uptake efficiency of 30% and this process is dose-dependent. EVs movement into intestinal epithelial cells was mainly through Z axis and scarcely on X and Y axis. This work demonstrates that EVs could be transported across the gastrointestinal epithelium. We speculate this mechanism could be the first step allowing EVs to reach the bloodstream for further delivery up to extraintestinal tissues and organs. The expression and further encapsulation of bioactive molecules into natural nanoparticles produced by probiotic bacteria could have practical implications in food, nutraceuticals and clinical therapies.
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9.
Unravelling the transcriptional responses of TGF-β: Smad3 and EZH2 constitute a regulatory switch that controls neuroretinal epithelial cell fate specification.
Andrews, D, Oliviero, G, De Chiara, L, Watson, A, Rochford, E, Wynne, K, Kennedy, C, Clerkin, S, Doyle, B, Godson, C, et al
FASEB journal : official publication of the Federation of American Societies for Experimental Biology. 2019;(5):6667-6681
Abstract
Cell differentiation is directed by extracellular cues and intrinsic epigenetic modifications, which control chromatin organization and transcriptional activation. Central to this process is PRC2, which modulates the di- and trimethylation of lysine 27 on histone 3; however, little is known concerning the direction of PRC2 to specific loci. Here, we have investigated the physical interactome of EZH2, the enzymatic core of PRC2, during retinoic acid-mediated differentiation of neuroepithelial, pluripotent NT2 cells and the dedifferentiation of neuroretinal epithelial ARPE19 cells in response to TGF-β. We identified Smad3 as an EZH2 interactor in both contexts. Co-occupation of the CDH1 promoter by Smad3 and EZH2 and the cooperative, functional nature of the interaction were established. We propose that the interaction between Smad3 and EZH2 targets the core polycomb assembly to defined regions of the genome to regulate transcriptional repression and forms a molecular switch that controls promoter access through epigenetic mechanisms leading to gene silencing.-Andrews, D., Oliviero, G., De Chiara, L., Watson, A., Rochford, E., Wynne, K., Kennedy, C., Clerkin, S., Doyle, B., Godson, C., Connell, P., O'Brien, C., Cagney, G., Crean, J. Unravelling the transcriptional responses of TGF-β: Smad3 and EZH2 constitute a regulatory switch that controls neuroretinal epithelial cell fate specification.
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10.
n-3 Polyunsaturated fatty acids alter benzo[a]pyrene metabolism and genotoxicity in human colon epithelial cell models.
Tylichová, Z, Neča, J, Topinka, J, Milcová, A, Hofmanová, J, Kozubík, A, Machala, M, Vondráček, J
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. 2019;:374-384
Abstract
Dietary carcinogens, such as benzo[a]pyrene (BaP), are suspected to contribute to colorectal cancer development. n-3 Polyunsaturated fatty acids (PUFAs) decrease colorectal cancer risk in individuals consuming diets rich in PUFAs. Here, we investigated the impact of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid on metabolism and genotoxicity of BaP in human cell models derived from the colon: HT-29 and HCT-116 cell lines. Both PUFAs reduced levels of excreted BaP metabolites, in particular BaP-tetrols and hydroxylated BaP metabolites, as well as formation of DNA adducts in HT-29 and HCT-116 cells. However, EPA appeared to be a more potent inhibitor of formation of some intracellular BaP metabolites, including BaP-7,8-dihydrodiol. EPA also reduced phosphorylation of histone H2AX (Ser139) in HT-29 cells, which indicated that it may reduce further forms of DNA damage, including DNA double strand breaks. Both PUFAs inhibited induction of CYP1 activity in colon cells determined as 7-ethoxyresorufin-O-deethylase (EROD); this was at least partly linked with inhibition of induction of CYP1A1, 1A2 and 1B1 mRNAs. The downregulation and/or inhibition of CYP1 enzymes by PUFAs could thus alter metabolism and reduce genotoxicity of BaP in human colon cells, which might contribute to known chemopreventive effects of PUFAs in colon epithelium.