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Ishikawa S, Nikaido M, Otani T, Ogata K, Iida H, Inai Y, Tamaoki S, Inai T. Inhibition of Retinoid X Receptor Improved the Morphology, Localization of Desmosomal Proteins, and Paracellular Permeability in Three-Dimensional Cultures of Mouse Keratinocytes. Microscopy (Oxf) 2022; 71:152-160. [PMID: 35289919 PMCID: PMC9169536 DOI: 10.1093/jmicro/dfac007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/04/2022] [Accepted: 02/16/2022] [Indexed: 11/14/2022] Open
Abstract
Retinoic acid (RA) plays an important role in epithelial homeostasis and influences the morphology, proliferation, differentiation and permeability of epithelial cells. Mouse keratinocytes, K38, reconstituted non-keratinized stratified epithelium in three-dimensional (3D) cultures with serum, which contains retinol (a source of RA), but the morphology was different from in vivo epithelium. The formed epithelium was thick, with loosened cell–cell contacts. Here, we investigated whether the inhibition of RA receptor (RAR)/retinoid X receptor (RXR)-mediated signaling by an RXR antagonist, HX 531, improved K38 3D cultures in terms of morphology and intercellular junctions. The epithelium formed by 0.5 μM HX531 was thin, and the intercellular space was narrowed because of the restoration of the layer-specific distribution of desmoglein (DSG)-1, DSG3 and plakoglobin (PG). Moreover, the levels of desmosomal proteins and tight junction proteins, including DSG1, DSG2, DSG3, PG, claudin (CLDN)-1 and CLDN4 increased, but the adherens junction protein, E-cadherin, did not show any change. Furthermore, CLDN1 was recruited to occludin-positive cell–cell contacts in the superficial cells and transepithelial electrical resistance was increased. Therefore, K38 3D cultures treated with 0.5 μM HX531 provides a useful in vitro model to study intercellular junctions in the non-keratinized epithelium.
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Affiliation(s)
- Shoko Ishikawa
- Department of Oral Growth and Development, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka 814-0193, Japan
| | - Misaki Nikaido
- Department of Odontology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka 814-0193, Japan
| | - Takahito Otani
- Department of Morphological Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka 814-0193, Japan
| | - Kayoko Ogata
- Department of Morphological Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka 814-0193, Japan
- Oral Medicine Research Center, Fukuoka Dental College, Fukuoka, 814-0193, Japan
| | - Hiroshi Iida
- Laboratory of Zoology, Graduate School of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yuko Inai
- Division of General Dentistry, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Sachio Tamaoki
- Department of Oral Growth and Development, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka 814-0193, Japan
| | - Tetsuichiro Inai
- Department of Morphological Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka 814-0193, Japan
- Oral Medicine Research Center, Fukuoka Dental College, Fukuoka, 814-0193, Japan
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Ergün P, Capanoglu D, Kipcak S, Bor S. Response of Esophageal Epithelium to Acute and Chronic Stress in Rabbits. Bull Exp Biol Med 2021; 171:582-587. [PMID: 34617182 DOI: 10.1007/s10517-021-05273-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Indexed: 12/17/2022]
Abstract
We studied electrophysiological changes in rabbit esophageal epithelium following acute (AS) and chronic stress (CS). Esophageal tissue was placed in Ussing chamber and the potential difference U between the luminal and abluminal sides, the short-circuit current Isc, as well as the tissue resistance R were measured. The initial values of these parameters for each sample were determined after the samples were stabilized in Ringer solution. Then, the tissues were exposed for 1 h to normal Ringer solution or Ringer solution with pH 4.0 and pH 1.7 with or without pepsin (0.25 mg/ml). Fluorescein was added to the luminal side of the sample to measure its permeability. In the AS group, U at Ringer solution (pH 1.7)+pepsin was significantly decreased in comparison with the baseline and control values (by 46 and 22%, respectively, p<0.05). R decreased by 74% in comparison with baseline, which little differed from the decrease in control samples exposed to Ringer solution (pH 1.7)+pepsin (by 62%). CS did not change U relative to baseline values, while changes in R were similar to those in the AS group. In the AS group, the permeability of the esophageal tissue perfused with Ringer solution (pH 1.7)+pepsin was significantly higher than in both the control and CS groups. AS, but not CS, made the esophageal epithelium more sensitive to the effects of noxious agents, disrupted barrier properties, and increased permeability. The effects of stress on gastroesophageal reflux disease symptoms can be related to severe exposure to acid and/or pepsin; however, the mechanisms other than epithelial defense should be evaluated.
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Affiliation(s)
- P Ergün
- Ege Reflux Study Group, Division of Gastroenterology, Izmir, Turkey.,Department of Medical Biochemistry, Izmir, Turkey
| | - D Capanoglu
- Ege Reflux Study Group, Division of Gastroenterology, Izmir, Turkey
| | - S Kipcak
- Ege Reflux Study Group, Division of Gastroenterology, Izmir, Turkey.,Department of Medical Biology, Faculty of Medicine, Ege University, Izmir, Turkey
| | - S Bor
- Ege Reflux Study Group, Division of Gastroenterology, Izmir, Turkey.
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Genes coding for transcription factors involved in stem cell maintenance are repressed by TGF-β and downstream of Slug/Snail2 in COPD bronchial epithelial progenitors. Mol Biol Rep 2021; 48:6729-6738. [PMID: 34436724 DOI: 10.1007/s11033-021-06664-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/17/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Basal stem/progenitor cells of airway epithelium from chronic obstructive pulmonary disease (COPD) patients have a decrease in differentiation and self-renewal potential. Our study aimed at identifying deregulations in the genetic program of these cells that could account for their exhaustion, focusing on genes downstream of the epithelial-mesenchymal transition-inducing transcription factor Slug/Snail2 and responding to transforming growth factor (TGF)-β. TGF-β is at higher levels in COPD patient lungs, plays a role in stem/progenitor cell fate and regulates the expression of Slug/Snail2 that is highly expressed in airway basal stem/progenitors. METHODS AND RESULTS We reanalyzed a gene expression dataset that we generated from COPD and normal primary bronchial basal progenitor cells knocked down for Slug/Snail2 gene. Among the genes that we identified to be repressed downstream of Slug/Snail2 in COPD, we selected those responding to differentiation and TGF-β. The large majority of these genes are upregulated with differentiation but repressed by TGF-β. Pathway and ontology enrichment analysis revealed a set of genes coding for transcription factors involved in stem cell maintenance that are repressed downstream of Slug/Snail2 and by TGF-β in COPD but not normal basal progenitor cells. We also reveal a link between Slug/Snail2 expression and the repressive effect of TGF-β on these stem cell maintenance genes. CONCLUSION Our work brings a new insight and molecular perspective to the exhaustion of basal stem/progenitor cells observed in the airway epithelium of COPD patients, revealing that stem cell maintenance genes are repressed in these cells, with TGF-β and Slug/Snail2 being involved in this deregulation.
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Nordberg M, Täubel M, Jalava PI, BéruBé K, Tervahauta A, Hyvärinen A, Huttunen K. Human airway construct model is suitable for studying transcriptome changes associated with indoor air particulate matter toxicity. INDOOR AIR 2020; 30:433-444. [PMID: 31883508 PMCID: PMC7217003 DOI: 10.1111/ina.12637] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 12/18/2019] [Accepted: 12/23/2019] [Indexed: 05/08/2023]
Abstract
In vitro models mimicking the human respiratory system are essential when investigating the toxicological effects of inhaled indoor air particulate matter (PM). We present a pulmonary cell culture model for studying indoor air PM toxicity. We exposed normal human bronchial epithelial cells, grown on semi-permeable cell culture membranes, to four doses of indoor air PM in the air-liquid interface. We analyzed the chemokine interleukin-8 concentration from the cell culture medium, protein concentration from the apical wash, measured tissue electrical resistance, and imaged airway constructs using light and transmission electron microscopy. We sequenced RNA using a targeted RNA toxicology panel for 386 genes associated with toxicological responses. PM was collected from a non-complaint residential environment over 1 week. Sample collection was concomitant with monitoring size-segregated PM counts and determination of microbial levels and diversity. PM exposure was not acutely toxic for the cells, and we observed up-regulation of 34 genes and down-regulation of 17 genes when compared to blank sampler control exposure. The five most up-regulated genes were related to immunotoxicity. Despite indications of incomplete cell differentiation, this model enabled the comparison of a toxicological transcriptome associated with indoor air PM exposure.
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Affiliation(s)
- Maria‐Elisa Nordberg
- Department of Environmental and Biological SciencesUniversity of Eastern Finland (UEF)KuopioFinland
| | - Martin Täubel
- Environmental Health UnitNational Institute for Health and WelfareKuopioFinland
| | - Pasi I. Jalava
- Department of Environmental and Biological SciencesUniversity of Eastern Finland (UEF)KuopioFinland
| | - Kelly BéruBé
- Cardiff School of BiosciencesCardiff Institute Tissue Engineering and Repair (CITER)Cardiff UniversityWalesUK
| | - Arja Tervahauta
- Department of Environmental and Biological SciencesUniversity of Eastern Finland (UEF)KuopioFinland
| | - Anne Hyvärinen
- Environmental Health UnitNational Institute for Health and WelfareKuopioFinland
| | - Kati Huttunen
- Department of Environmental and Biological SciencesUniversity of Eastern Finland (UEF)KuopioFinland
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Yin XL, Zhong L, Lin CY, Shi XS, Zhang J, Chen ZY, Che H, Ma XX, Tian YX, Duan YZ, Lu L, Ji HJ, Zhao YP, Tang XD, Wang FY. Tojapride Reverses Esophageal Epithelial Inflammatory Responses on Reflux Esophagitis Model Rats. Chin J Integr Med 2020; 27:604-612. [PMID: 32248515 DOI: 10.1007/s11655-019-3027-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2017] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To investigate the mechanism of Tojapride, a Chinese herbal formula extract, on strengthening the barrier function of esophageal epithelium in rats with reflux esophagitis (RE). METHODS Ten out of 85 SD rats were randomly selected as the sham group (n10), and 75 rats were developed a reflux esophagitis model (RE) by the esophageal and duodenal side-to-side anastomosis. Fifty successful modeling rats were divided into different medicated groups through a random number table including the model, low-, medium-, and high-dose of Tojapride as well as omeprazole groups (n10). Three doses of Tojapride [5.73, 11.46, 22.92 g/(kg•d)] and omeprazole [4.17 mg/(kg•d)] were administrated intragastrically twice daily for 3 weeks. And the rats in the sham and model groups were administered 10 mL/kg distilled water. Gastric fluid was collected and the supernatant was kept to measure for volume, pH value and acidity. Esophageal tissues were isolated to monitor the morphological changes through hematoxylin-eosin (HE) staining, and esophageal epithelial ultrastructure was observed by transmission electron microscopy. The expressions of nuclear factor kappa-light-chain-enhancer of activated B cells p65 (NF-KBp65), κB kinase beta (IKKß), occludin, and zonula occludens-1 (ZO-1) in the esophageal tissues were measured by immunohistochemistry and Western blot, respectively. RESULTS The gastric pH value in the model group was significantly lower than the sham group (P<0.05). Compared with the model group, gastric pH value in the omeprazole and medium-dose of Tojapride groups were significantly higher (P<0.05). A large area of ulceration was found on the esophageal mucosa from the model rats, while varying degrees of congestion and partially visible erosion was observed in the remaining groups. Remarkable increase in cell gap width and decrease in desmosome count was seen in RE rats and the effect was reversed by Tojapride treatment. Compared with the sham group, the IKKß levels were significantly higher in the model group (P<0.05). However, the IKKß levels were down-regulated after treatment by all doses of Tojapride (P<0.01 or P<0.05). The occluding and ZO-1 levels decreased in the model group compared with the sham group (Ps0.01 or Ps0.05), while both indices were significantly up-regulated in the Tojapride-treated groups (P<0.01 or P<0.05). CONCLUSIONS Tojapride could improve the pathological conditions of esophageal epithelium in RE rats. The underlying mechanisms may involve in down-regulating the IKKß expression and elevating ZO-1 and occludin expression, thereby alleviating the inflammation of the esophagus and strengthening the barrier function of the esophageal epithelium.
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Affiliation(s)
- Xiao-Lan Yin
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China
| | - Linda Zhong
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region, Kowloon, China
| | - Cheng-Yuan Lin
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong Special Administrative Region, Kowloon, China
| | - Xiao-Shuang Shi
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China
| | - Jiao Zhang
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China
- Department of Gastroenterology, Changping Hospital of Traditional Chinese Medicine, Beijing, 102200, China
| | - Zheng-Yi Chen
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China
- Department of Traditional Chinese Medicine, Dongfeng General Hospital, Shiyan, Hubei Province, 442000, China
| | - Hui Che
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China
| | - Xiang-Xue Ma
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China
| | - Ya-Xin Tian
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China
| | - Yuan-Zhi Duan
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China
| | - Lin Lu
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China
| | - Hai-Jie Ji
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China
| | - Ying-Pan Zhao
- Center of Clinical Pharmacology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China
| | - Xu-Dong Tang
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China
| | - Feng-Yun Wang
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, 100091, China.
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Leung C, Wadsworth SJ, Yang SJ, Dorscheid DR. Structural and functional variations in human bronchial epithelial cells cultured in air-liquid interface using different growth media. Am J Physiol Lung Cell Mol Physiol 2020; 318:L1063-L1073. [PMID: 32208929 DOI: 10.1152/ajplung.00190.2019] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The human bronchial epithelium is an important barrier tissue that is damaged or pathologically altered in various acute and chronic respiratory conditions. To represent the epithelial component of respiratory disease, it is essential to use a physiologically relevant model of this tissue. The human bronchial epithelium is a highly organized tissue consisting of a number of specialized cell types. Primary human bronchial epithelial cells (HBEC) can be differentiated into a mucociliated tissue in air-liquid interface (ALI) cultures using appropriately supplemented media under optimized growth conditions. We compared the histology, ciliary length, and function, diffusion, and barrier properties of HBEC from donors with no respiratory disease grown in two different media, PneumaCult-ALI or Bronchial Epithelial Differentiation Medium (BEDM). In the former group, HBEC have a more physiological pseudostratified morphology and mucociliary differentiation, including increased epithelial thickness, intracellular expression of airway-specific mucin protein MUC5AC, and total expression of cilia basal-body protein compared with cells from the same donor grown in the other medium. Baseline expression levels of inflammatory mediators, thymic stromal lymphopoietin (TSLP), soluble ST2, and eotaxin-3 were lower in PneumaCult-ALI. Additionally, the physiological cilia beat frequency and electrical barrier properties with transepithelial electrical resistance were significantly different between the two groups. Our study has shown that these primary cell cultures from the same donor grown in the two media possess variable structural and functional characteristics. Therefore, it is important to objectively validate primary epithelial cell cultures before experimentation to ensure they are appropriate to answer a specific scientific question.
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Affiliation(s)
- Clarus Leung
- Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Samuel J Wadsworth
- Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - S Jasemine Yang
- Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Delbert R Dorscheid
- Centre for Heart Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
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Miyazono S, Otani T, Ogata K, Kitagawa N, Iida H, Inai Y, Matsuura T, Inai T. The reduced susceptibility of mouse keratinocytes to retinoic acid may be involved in the keratinization of oral and esophageal mucosal epithelium. Histochem Cell Biol 2020; 153:225-237. [PMID: 32006103 DOI: 10.1007/s00418-020-01845-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2020] [Indexed: 10/24/2022]
Abstract
Keratinocytes take up serum-derived retinol (vitamin A) and metabolize it to all-trans-retinoic acid (atRA), which binds to the nuclear retinoic acid receptor (RAR). We previously reported that serum-affected keratinocyte differentiation and function; namely, it inhibited keratinization, decreased loricrin (LOR) and claudin (CLDN) 1 expression, increased keratin (K) 4 and CLDN4 levels, and reduced paracellular permeability in three-dimensional (3D) cultures of mouse keratinocytes (COCA). Contrarily, RAR inhibition reversed these changes. Here, we aimed to examine whether atRA exerted the same effects as serum, and whether it was involved in the differential oral mucosa keratinization among animal species. Porcine oral mucosal keratinocytes, which form non-keratinized epithelium in vivo, established keratinized epithelium in 3D cultures. Both mouse and porcine sera induced non-keratinized epithelium at 0.1% in COCA 3D cultures. Although atRA caused the same changes as serum, its effective concentration differed. atRA inhibited keratinization at 0.1 nM and 1 nM in porcine or human keratinocytes and COCA, respectively. Furthermore, atRA upregulated CLDN7 in the cytoplasm but not in cell-cell contacts. These atRA-induced changes were reverted by RAR inhibition. The results indicate that serum-induced changes are probably due to the effect of serum-derived atRA, and that mouse keratinocytes require higher atRA concentrations to suppress keratinization than porcine and human keratinocytes. We propose that the lower susceptibility of mouse keratinocytes to atRA, rather than a lower retinol concentration, is a possible reason for the keratinization of mouse oral mucosal epithelium.
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Affiliation(s)
- Shoji Miyazono
- Department of Oral Rehabilitation, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - Takahito Otani
- Department of Morphological Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - Kayoko Ogata
- Department of Morphological Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - Norio Kitagawa
- Department of Morphological Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - Hiroshi Iida
- Laboratory of Zoology, Graduate School of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Yuko Inai
- Division of General Dentistry, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Takashi Matsuura
- Department of Oral Rehabilitation, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan
| | - Tetsuichiro Inai
- Department of Morphological Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, 814-0193, Japan.
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Nakhoul NL, Tu CL, Brown KL, Islam MT, Hodges AG, Abdulnour-Nakhoul SM. Calcium-sensing receptor deletion in the mouse esophagus alters barrier function. Am J Physiol Gastrointest Liver Physiol 2020; 318:G144-G161. [PMID: 31709833 PMCID: PMC6985844 DOI: 10.1152/ajpgi.00021.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Calcium-sensing receptor (CaSR) is the molecular sensor by which cells respond to small changes in extracellular Ca2+ concentrations. CaSR has been reported to play a role in glandular and fluid secretion in the gastrointestinal tract and to regulate differentiation and proliferation of skin keratinocytes. CaSR is present in the esophageal epithelium, but its role in this tissue has not been defined. We deleted CaSR in the mouse esophagus by generating keratin 5 CreER;CaSRFlox+/+compound mutants, in which loxP sites flank exon 7 of CaSR gene. Recombination was initiated with multiple tamoxifen injections, and we demonstrated exon 7 deletion by PCR analysis of genomic DNA. Quantitative real-time PCR and Western blot analyses showed a significant reduction in CaSR mRNA and protein expression in the knockout mice (EsoCaSR-/-) as compared with control mice. Microscopic examination of EsoCaSR-/- esophageal tissues showed morphological changes including elongation of the rete pegs, abnormal keratinization and stratification, and bacterial buildup on the luminal epithelial surface. Western analysis revealed a significant reduction in levels of adherens junction proteins E-cadherin and β catenin and tight junction protein claudin-1, 4, and 5. Levels of small GTPase proteins Rac/Cdc42, involved in actin remodeling, were also reduced. Ussing chamber experiments showed a significantly lower transepithelial resistance in knockout (KO) tissues. In addition, luminal-to-serosal-fluorescein dextran (4 kDa) flux was higher in KO tissues. Our data indicate that CaSR plays a role in regulating keratinization and cell-cell junctional complexes and is therefore important for the maintenance of the barrier function of the esophagus.NEW & NOTEWORTHY The esophageal stratified squamous epithelium maintains its integrity by continuous proliferation and differentiation of the basal cells. Here, we demonstrate that deletion of the calcium-sensing receptor, a G protein-coupled receptor, from the basal cells disrupts the structure and barrier properties of the epithelium.
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Affiliation(s)
- Nazih L. Nakhoul
- 1Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana,2Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Chia-Ling Tu
- 3Endocrine Unit, Veterans Affairs Medical Center, University of California, San Francisco, California
| | - Karen L. Brown
- 1Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana,2Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana
| | - M. Toriqul Islam
- 1Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana,2Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Anna G. Hodges
- 1Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana,2Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Solange M. Abdulnour-Nakhoul
- 1Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana,2Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana,4Southeast Louisiana Veterans Health Care System, New Orleans, Louisiana
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Ozaki A, Otani T, Kitagawa N, Ogata K, Iida H, Kojima H, Inai T. Serum affects keratinization and tight junctions in three-dimensional cultures of the mouse keratinocyte cell line COCA through retinoic acid receptor-mediated signaling. Histochem Cell Biol 2018; 151:315-326. [DOI: 10.1007/s00418-018-1741-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/09/2018] [Indexed: 01/15/2023]
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Anisomycin, a JNK and p38 activator, suppresses cell-cell junction formation in 2D cultures of K38 mouse keratinocyte cells and reduces claudin-7 expression, with an increase of paracellular permeability in 3D cultures. Histochem Cell Biol 2018; 151:369-384. [PMID: 30284609 DOI: 10.1007/s00418-018-1736-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2018] [Indexed: 01/28/2023]
Abstract
Keratinocytes in the oral mucosal epithelium, which is a non-keratinized stratified epithelium, are exposed to various stimuli from the oral cavity. JNK and p38 are stress-activated mitogen-activated protein kinases (MAPKs) that are phosphorylated by various stimuli and are involved in the assembly and disassembly of tight junctions (TJs) in keratinocytes. Therefore, we investigated the effects of stress-activated MAPKs on TJs in a mouse keratinocyte cell line during cell-cell junction formation in two-dimensional (2D) cultures or stratification to form non-keratinized epithelium in 3D cultures. In 2D cultures, calcium induced zipper-like staining for ZO-1 at 2 h and string-like staining for ZO-1 at 12 h, which indicated immature and mature cell-cell junctions, respectively. Anisomycin (AM), a JNK and p38 activator, inhibited formation of string-like staining for ZO-1, whereas inhibition of JNK, but not p38, after AM treatment restored string-like staining for ZO-1, although claudins (CLDNs) 4, 6, and 7 did not completely colocalize to ZO-1-positive sites. In 3D cultures, AM treatment for 2 weeks activated only p38, suppressed flattening of the superficial cells, removed CLDN7 from ZO-1-positive spots on the surface of 3D cultures, which represent TJs, and decreased transepithelial electrical resistance. Thus, short-term AM treatment inhibited maturation of cell-cell junctions by JNK, but not p38, activation. p38 activation by long-term AM treatment affected morphology of stratified structures and paracellular permeability, which was increased by CLDN7 removal from TJs. Various chronic stimuli that activate stress-activated MAPKs may weaken the keratinocyte barrier and be involved in TJ-related diseases.
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Wu L, Oshima T, Li M, Tomita T, Fukui H, Watari J, Miwa H. Filaggrin and tight junction proteins are crucial for IL-13-mediated esophageal barrier dysfunction. Am J Physiol Gastrointest Liver Physiol 2018; 315:G341-G350. [PMID: 29746170 DOI: 10.1152/ajpgi.00404.2017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Eosinophilic esophagitis (EoE) is an allergy-mediated disease that is accompanied by IL-13 overexpression and an impaired esophageal barrier. Filaggrin (FLG) and tight junction (TJ) proteins are considered to contribute to epithelial barrier function. However, their functional involvement in EoE has not been elucidated. Here, we aimed to determine the IL-13-mediated barrier dysfunction and expression of TJ-related proteins in EoE and to characterize interactions among TJ-related proteins involved in the barrier function of the esophageal epithelium. Biopsy specimens from EoE patients were analyzed. Primary human esophageal epithelial cells (HEECs) were cultured using an air-liquid interface (ALI) system. The permeability of TJs was assayed by biotinylation. Transepithelial electrical resistance (TEER) was measured after stimulation with IL-13 and after siRNA silencing of FLG expression. FLG and TJ genes and proteins were assessed by quantitative RT-PCR, Western blot analysis, and immunofluorescent staining. The biotinylation reagent diffused through the paracellular spaces of whole stratified epithelial layers in EoE biopsy samples. The TEER decreased in ALI-cultured HEECs after IL-13 stimulation. Although the protein level of FLG decreased, that of the TJ proteins increased in the mucosa of EoE biopsy samples and in ALI-cultured HEECs after IL-13 stimulation. IL-13 altered the staining patterns of TJ proteins and the epithelial morphology. FLG siRNA transfection significantly decreased TEER. The IL-13-mediated reduced esophageal barrier is associated with the altered expression pattern but not with the levels of TJ-associated proteins. A deficiency of FLG altered the stratified epithelial barrier. NEW & NOTEWORTHY Esophageal permeability to small molecules was increased in patients with eosinophilic esophagitis (EoE) and could be induced by IL-13 in our unique air-liquid interface-cultured primary multilayer human esophageal epithelial cells in vitro. A deficiency of filaggrin disrupted the esophageal stratified epithelial barrier. The decreased esophageal barrier in EoE was associated with the altered staining pattern of tight junction proteins, although the levels of the proteins themselves do not appear to be changed.
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Affiliation(s)
- Liping Wu
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine , Nishinomiya , Japan.,Department of Gastroenterology, The Third People's Hospital of Chengdu , Chengdu , China
| | - Tadayuki Oshima
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine , Nishinomiya , Japan
| | - Min Li
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine , Nishinomiya , Japan.,Department of Gastroenterology, The Third People's Hospital of Chengdu , Chengdu , China
| | - Toshihiko Tomita
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine , Nishinomiya , Japan
| | - Hirokazu Fukui
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine , Nishinomiya , Japan
| | - Jiro Watari
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine , Nishinomiya , Japan
| | - Hiroto Miwa
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine , Nishinomiya , Japan
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12
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Wu L, Oshima T, Fukui H, Watari J, Miwa H. Adenosine triphosphate induces P2Y2 activation and interleukin-8 release in human esophageal epithelial cells. J Gastroenterol Hepatol 2017; 32:1341-1347. [PMID: 27977904 DOI: 10.1111/jgh.13672] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 10/05/2016] [Accepted: 12/07/2016] [Indexed: 12/17/2022]
Abstract
BACKGROUND AND AIM Immune-mediated mucosal inflammation characterized by the release of interleukin (IL)-8 is associated with gastroesophageal reflux disease. ATP released by human esophageal epithelial cells (HEECs) mediates the release of cytokines through P2 nucleotide receptors that are present on various cells, including HEECs. This study characterized and identified human esophageal epithelial P2 receptors that are responsible for ATP-mediated release of IL-8 by using a human esophageal stratified squamous epithelial model. METHODS Primary HEECs were cultured with the use of an air-liquid interface (ALI) system. The ATP analogue adenosine 5'-O-3-thiotriphosphate (ATP-γ-S) was added to the basolateral compartment, and IL-8 release was measured. Involvement of the P2Y2 receptor was assessed with the use of selective and non-selective receptor antagonists and a P2Y2 receptor agonist. Expression of the P2Y2 receptor was assessed using western blotting and immunohistochemistry. RESULTS Adenosine triphosphate-γ-S induced IL-8 release through the P2Y2 receptor. A P2Y2 receptor antagonist but not a P2X3 receptor antagonist or a P2Y1 receptor antagonist blocked ATP-γ-S-mediated IL-8 release. Conversely, a P2Y2 receptor agonist induced IL-8 release. Western blotting and immunohistochemistry of the P2Y2 receptor showed strong expression of the P2Y2 receptor on ALI-cultured HEECs and in human esophagus. Inhibition of extracellular signal-regulated kinase but not of protein kinase C blocked the ATP-mediated release of IL-8. ATP-γ-S induced phosphorylation of extracellular signal-regulated kinase, and a P2Y2 receptor antagonist blocked this phosphorylation. CONCLUSIONS Interleukin-8 release after purinergic stimulation in ALI-cultured HEECs is mediated through P2Y2 receptor activation. ATP-induced IL-8 release maybe involved in the pathogenesis of refractory gastroesophageal reflux disease.
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Affiliation(s)
- Liping Wu
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan.,Department of Gastroenterology, The Third People's Hospital of Chengdu, Chengdu, China
| | - Tadayuki Oshima
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Hirokazu Fukui
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Jiro Watari
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Hiroto Miwa
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
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13
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Wu L, Oshima T, Tomita T, Ohda Y, Fukui H, Watari J, Miwa H. Serotonin disrupts esophageal mucosal integrity: an investigation using a stratified squamous epithelial model. J Gastroenterol 2016; 51:1040-1049. [PMID: 26984549 DOI: 10.1007/s00535-016-1195-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 03/06/2016] [Indexed: 02/04/2023]
Abstract
BACKGROUND Serotonin regulates gastrointestinal function, and mast cells are a potential nonneuronal source of serotonin in the esophagus. Tight junction (TJ) proteins in the esophageal epithelium contribute to the barrier function, and the serotonin signaling pathway may contribute to epithelial leakage in gastroesophageal reflux disease. Therefore, the aim of this study was to investigate the role of serotonin on barrier function, TJ proteins, and related signaling pathways. METHODS Normal primary human esophageal epithelial cells were cultured with use of an air-liquid interface system. Serotonin was added to the basolateral compartment, and transepithelial electrical resistance (TEER) was measured. The expression of TJ proteins and serotonin receptor 7 (5-HT7) was assessed by Western blotting. The involvement of 5-HT7 was assessed with use of an antagonist and an agonist. The underlying cellular signaling pathways were examined with use of specific blockers. RESULTS Serotonin decreased TEER and reduced the expression of TJ proteins ZO-1, occludin, and claudin 1, but not claudin 4. A 5-HT7 antagonist blocked the serotonin-induced decrease in TEER, and a 5-HT7 agonist decreased TEER. Inhibition of p38 mitogen-activated protein kinase (MAPK) reduced the serotonin-induced decrease in TEER. Inhibition of p38 MAPK blocked the decrease of ZO-1 levels, whereas extracellular-signal-regulated kinase (ERK) inhibition blocked the decrease in occludin levels. Cell signaling pathway inhibitors had no effect on serotonin-induced alterations in claudin 1 and claudin 4 levels. Serotonin induced phosphorylation of p38 MAPK and ERK, and a 5-HT7 antagonist partially blocked serotonin-induced phosphorylation of p38 MAPK but not that of ERK. CONCLUSIONS Serotonin disrupted esophageal squamous epithelial barrier function by modulating the levels of TJ proteins. Serotonin signaling pathways may mediate the pathogenesis of gastroesophageal reflux disease.
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Affiliation(s)
- Liping Wu
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan.,Department of Gastroenterology, The Third People's Hospital of Chengdu, Chengdu, China
| | - Tadayuki Oshima
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan.
| | - Toshihiko Tomita
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan
| | - Yoshio Ohda
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan
| | - Hirokazu Fukui
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan
| | - Jiro Watari
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan
| | - Hiroto Miwa
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan
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14
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Abstract
The gastrointestinal mucosal barrier plays an essential role in the separation of the inside of the body from the outside environment. Tight junctions (TJs) are the most important component for construction of a constitutive barrier of epithelial cells, and they regulate the permeability of the barrier by tightly sealing the cell-cell junctions. TJ proteins are represented by claudins, occludin, junctional adhesion molecules, and scaffold protein zonula occludens. Among these TJ proteins, claudins are the major components of TJs and are responsible for the barrier and the polarity of the epithelial cells. Gastrointestinal diseases including reflux esophagitis, inflammatory bowel disease, functional gastrointestinal disorders, and cancers may be regulated by these molecules, and disruption of their functions leads to chronic inflammatory conditions and chronic or progressive disease. Therefore, regulation of the barrier function of epithelial cells by regulating the expression and localization of TJ proteins is a potential new target for the treatment of these diseases. Treatment strategies for these diseases might thus be largely altered if symptom generation and/or immune dysfunction could be regulated through improvement of mucosal barrier function. Since TJ proteins may also modify tumor infiltration and metastasis, other important goals include finding a good TJ biomarker of cancer progression and patient prognosis, and developing TJ protein-targeted therapies that can modify patient prognosis. This review summarizes current understanding of gastrointestinal barrier function, TJ protein expression, and the mechanisms underlying epithelial barrier dysregulation in gastrointestinal diseases.
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15
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Li J, Chen XL, Shaker A, Oshima T, Shan J, Miwa H, Feng C, Zhang J. Contribution of immunomodulators to gastroesophageal reflux disease and its complications: stromal cells, interleukin 4, and adiponectin. Ann N Y Acad Sci 2016; 1380:183-194. [PMID: 27441783 DOI: 10.1111/nyas.13157] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 05/29/2016] [Accepted: 06/01/2016] [Indexed: 12/15/2022]
Abstract
Gastroesophageal reflux disease (GERD) has become the most commonly seen gastrointestinal disorder in outpatient clinics. In the United States, around 20% of the general population experience heartburn on a weekly basis. Although clinical complaints can be mild or moderate, patients with GERD may develop further complications, such as peptic strictures, Barrett's esophagus (BE), and even esophageal adenocarcinoma. Pathologically, GERD is developed as a result of chronic and enhanced exposure of the esophageal epithelium to noxious gastric refluxate. In this review article, we provide an overview of GERD and then focus on the roles of stromal cells, interleukin 4, and adiponectin in GERD and BE. The importance of inflammation and immunomodulators in GERD pathogenesis is highlighted. Targeting the immunomodulators or inflammation in general may improve the therapeutic outcome of GERD, in particular, in those refractory to proton pump inhibitors.
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Affiliation(s)
- Jing Li
- Department of Thoracic Surgery, Ningxia Medical University General Hospital, Yinchuan, Ningxia, China.,Cancer Research Program, JLC-BBRI, North Carolina Central University, Durham, North Carolina
| | - Xiaoxin Luke Chen
- Cancer Research Program, JLC-BBRI, North Carolina Central University, Durham, North Carolina. .,Center for Esophageal Disease and Swallowing, Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
| | - Anisa Shaker
- Division of Gastroenterology, Department of Medicine, University of Southern California, Keck School of Medicine, Los Angeles, California.
| | - Tadayuki Oshima
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
| | - Jing Shan
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Hiroto Miwa
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Cheng Feng
- Department of Gastroenterology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China.
| | - Jun Zhang
- Department of Gastroenterology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
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16
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Gastroesophageal reflux disease-related and functional heartburn: pathophysiology and treatment. Curr Opin Gastroenterol 2016; 32:344-52. [PMID: 27206157 DOI: 10.1097/mog.0000000000000282] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW Patients who continue to experience heartburn symptoms despite adequate-dose proton pump inhibitor therapy have unmet clinical needs. In this review, we focus on the most recent findings related to the mechanism of heartburn symptom generation, and on the treatment of gastroesophageal reflux disease-related and functional heartburn. RECENT FINDINGS The immunological mechanism in the esophageal mucosa has been addressed as a potential mechanism of the onset of esophageal mucosa damage and the generation of heartburn symptoms. Peripheral or central hypersensitivity in viscera is a potentially unifying pathophysiological concept in functional heartburn. Vonoprazan, a novel and potent first-in-class potassium-competitive acid blocker, is expected to prove useful in the treatment of reflux disease. SUMMARY New findings in the mechanisms of heartburn symptom generation are emerging, including the immunological mediation of esophageal mucosal damage and the development of visceral hypersensitivity in functional heartburn. In the future, we anticipate the emergence of new and specific therapeutic options based on these mechanisms, with less dependence on acid-suppressing agents.
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17
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Shan J, Oshima T, Wu L, Fukui H, Watari J, Miwa H. Interferon γ-Induced Nuclear Interleukin-33 Potentiates the Release of Esophageal Epithelial Derived Cytokines. PLoS One 2016; 11:e0151701. [PMID: 26986625 PMCID: PMC4795790 DOI: 10.1371/journal.pone.0151701] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 03/02/2016] [Indexed: 12/14/2022] Open
Abstract
Background Esophageal epithelial cells are an initiating cell type in esophageal inflammation, playing an essential role in the pathogenesis of gastroesophageal reflux disease (GERD). A new tissue-derived cytokine, interleukin-33 (IL-33), has been shown to be upregulated in esophageal epithelial cell nuclei in GERD, taking part in mucosal inflammation. Here, inflammatory cytokines secreted by esophageal epithelial cells, and their regulation by IL-33, were investigated. Methods In an in vitro stratified squamous epithelial model, IL-33 expression was examined using quantitative RT-PCR, western blot, ELISA, and immunofluorescence. Epithelial cell secreted inflammatory cytokines were examined using multiplex flow immunoassay. IL-33 was knocked down with small interfering RNA (siRNA) in normal human esophageal epithelial cells (HEECs). Pharmacological inhibitors and signal transducers and activators of transcription 1 (STAT1) siRNA were used to explore the signaling pathways. Results Interferon (IFN)γ treatment upregulated nuclear IL-33 in HEECs. Furthermore, HEECs can produce various inflammatory cytokines, such as IL-6, IL-8, monocyte chemoattractant protein 1 (MCP-1), regulated on activation normal T-cell expressed and presumably secreted (RANTES), and granulocyte-macrophage colony-stimulating factor (GM-CSF) in response to IFNγ. Nuclear, but not exogenous IL-33, amplified IFN induction of these cytokines. P38 mitogen-activated protein kinase (MAPK) and janus protein tyrosine kinases (JAK)/STAT1 were the common signaling pathways of IFNγ-mediated induction of IL-33 and other cytokines. Conclusions Esophageal epithelial cells can actively participate in GERD pathogenesis through the production of various cytokines, and epithelial-derived IL-33 might play a central role in the production of these cytokines.
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Affiliation(s)
- Jing Shan
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
- Department of Gastroenterology, The Third People's Hospital of Chengdu, Chengdu, China
| | - Tadayuki Oshima
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
- * E-mail:
| | - Liping Wu
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
- Department of Gastroenterology, The Third People's Hospital of Chengdu, Chengdu, China
| | - Hirokazu Fukui
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Jiro Watari
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Hiroto Miwa
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
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18
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Song MJ, Davis CI, Lawrence GG, Margulies SS. Local influence of cell viability on stretch-induced permeability of alveolar epithelial cell monolayers. Cell Mol Bioeng 2015; 9:65-72. [PMID: 26958093 DOI: 10.1007/s12195-015-0405-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Ventilator induced lung injury (VILI), often attributed to over-distension of the alveolar epithelial cell layer, can trigger loss of barrier function. Alveolar epithelial cell monolayers can be used as an idealized in vitro model of the pulmonary epithelium, with cell death and tight junction disruption and permeability employed to estimate stretch-induced changes in barrier function. We adapted a method published for vascular endothelial permeability, compare its sensitivity with our previously published method, and determine the relationship between breeches in barrier properties after stretch and regions of cell death After 4-5 days in culture, primary rat alveolar epithelial cells seeded on plasma treated polydimethylsiloxane membrane coated with biotin-labeled fibronectin, or fibronectin alone were stretched in the presence of FITC-tagged streptavidin (biotin-labeled membrane) or BODIPY-ouabain. We found that the FITC-labeling method was a more sensitive indicator of permeability disruption, with significantly larger positively stained areas visible in the presence of stretch and with ATP production inhibitor Antimycin-A. Triple-stained images with Hoescht (nuclei), Ethidium Homodimer (EthD, damaged cell nuclei) and FITC (permeable regions) were used to determine that within permeable regions intact cells were positioned closer to damaged cells than in non-permeable regions. We concluded that local cell death may be an important contributor to barrier integrity.
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Affiliation(s)
- M J Song
- Department of Bioengineering, University of Pennsylvania 210 South 33rd Street, Philadelphia, PA 19104-6321, USA
| | - C I Davis
- Department of Bioengineering, University of Pennsylvania 210 South 33rd Street, Philadelphia, PA 19104-6321, USA
| | - G G Lawrence
- Department of Bioengineering, University of Pennsylvania 210 South 33rd Street, Philadelphia, PA 19104-6321, USA
| | - S S Margulies
- Department of Bioengineering, University of Pennsylvania 210 South 33rd Street, Philadelphia, PA 19104-6321, USA
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19
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Woodland P, Batista-Lima F, Lee C, Preston SL, Dettmar P, Sifrim D. Topical protection of human esophageal mucosal integrity. Am J Physiol Gastrointest Liver Physiol 2015; 308:G975-80. [PMID: 25907692 DOI: 10.1152/ajpgi.00424.2014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 04/15/2015] [Indexed: 01/31/2023]
Abstract
Patients with nonerosive reflux disease exhibit impaired esophageal mucosal integrity, which may underlie enhanced reflux perception. In vitro topical application of an alginate solution can protect mucosal biopsies against acid-induced changes in transepithelial electrical resistance (TER). We aimed to confirm this finding in a second model using 3D cell cultures and to assess prolonged protection in a biopsy model. We assessed the protective effect of a topically applied alginate solution 1 h after application. 3D cell cultures were grown by using an air-liquid interface and were studied in Ussing chambers. The apical surface was "protected" with 200 μl of either alginate or viscous control or was unprotected. The tissue was exposed to pH 3 + bile acid solution for 30 min and TER change was calculated. Distal esophageal mucosal biopsies were taken from 12 patients and studied in Ussing chambers. The biopsies were coated with either alginate or viscous control solution. The biopsies were then bathed in pH 7.4 solution for 1 h. The luminal chamber solution was replaced with pH 2 solution for 30 min. Percentage changes in TER were recorded. In five biopsies fluorescein-labeled alginate solution was used to allow immunohistological localization of the alginate after 1 h. In the cell culture model, alginate solution protected tissue against acid-induced change in TER. In biopsies, 60 min after protection with alginate solution, the acidic exposure caused a -8.3 ± 2.2% change in TER compared with -25.1 ± 4.5% change after protection with the viscous control (P < 0.05). Labeled alginate could be seen coating the luminal surface in all cases. In vitro, alginate solutions can adhere to the esophageal mucosa for up to 1 h and exert a topical protectant effect. Durable topical protectants can be further explored as first-line/add-on therapies for gastroesophageal reflux disease.
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Affiliation(s)
- P Woodland
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - F Batista-Lima
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK; Universidade Federal do Ceará, Fortaleza, Brazil; and
| | - C Lee
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - S L Preston
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | | | - D Sifrim
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK;
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20
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Shan J, Oshima T, Muto T, Yasuda K, Fukui H, Watari J, Nakanishi K, Miwa H. Epithelial-derived nuclear IL-33 aggravates inflammation in the pathogenesis of reflux esophagitis. J Gastroenterol 2015; 50:414-23. [PMID: 25129514 DOI: 10.1007/s00535-014-0988-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 08/03/2014] [Indexed: 02/07/2023]
Abstract
BACKGROUND IL-33 is a new tissue-derived cytokine constitutively expressed in epithelial cells and plays a role in sensing damage caused by inflammatory diseases. The function of IL-33 in the esophageal mucosa has not been previously described. Accordingly, we examined the expression of IL-33 and its role in the pathogenesis of reflux esophagitis (RE). METHODS IL-33 in the esophageal mucosa of RE patients and in an in vitro stratified normal esophageal squamous epithelial model was examined at the messenger RNA and protein levels. The correlation of the level of IL-33 and IL-8 or IL-6 was examined. Cell layers were stimulated with bile acids and cytokines. IL-33 was knocked down by small interfering RNA (siRNA). Pharmacological inhibitors and signal transducer and activator of transcription 1 (STAT1) siRNA were used. RESULTS IL-33 was significantly upregulated in RE patients, and was located in the nuclei of basal and suprabasal layers. Upregulated IL-33 messenger RNA expression was correlated with IL-8 and IL-6 expression. In vitro, IL-33 was upregulated in the nuclei of basal and suprabasal layers by interferon-γ (IFNγ), and the upregulation was aggravated by the combination of deoxycholic acid (DCA) and IFNγ. IL-33 knockdown dampened IFNγ- and DCA-induced IL-8 and IL-6 production. IFNγ-induced IL-33 was inhibited by a Janus kinase inhibitor, a p38 mitogen-activated protein kinase inhibitor, and STAT1 siRNA. CONCLUSIONS Nuclear IL-33 is upregulated in erosive mucosa of RE patients and is correlated with IL-8 and IL-6 levels. The normal esophageal epithelial model enables us to show for the first time that epithelial-cell-derived nuclear but not exogenous IL-33 is located upstream of the production of inflammatory cytokines and can aggravate the inflammation.
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Affiliation(s)
- Jing Shan
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan
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Srinivasan B, Kolli AR, Esch MB, Abaci HE, Shuler ML, Hickman JJ. TEER measurement techniques for in vitro barrier model systems. ACTA ACUST UNITED AC 2015; 20:107-26. [PMID: 25586998 DOI: 10.1177/2211068214561025] [Citation(s) in RCA: 1263] [Impact Index Per Article: 140.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Transepithelial/transendothelial electrical resistance (TEER) is a widely accepted quantitative technique to measure the integrity of tight junction dynamics in cell culture models of endothelial and epithelial monolayers. TEER values are strong indicators of the integrity of the cellular barriers before they are evaluated for transport of drugs or chemicals. TEER measurements can be performed in real time without cell damage and generally are based on measuring ohmic resistance or measuring impedance across a wide spectrum of frequencies. The measurements for various cell types have been reported with commercially available measurement systems and also with custom-built microfluidic implementations. Some of the barrier models that have been widely characterized using TEER include the blood-brain barrier (BBB), gastrointestinal (GI) tract, and pulmonary models. Variations in these values can arise due to factors such as temperature, medium formulation, and passage number of cells. The aim of this article is to review the different TEER measurement techniques and analyze their strengths and weaknesses, determine the significance of TEER in drug toxicity studies, examine the various in vitro models and microfluidic organs-on-chips implementations using TEER measurements in some widely studied barrier models (BBB, GI tract, and pulmonary), and discuss the various factors that can affect TEER measurements.
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Affiliation(s)
- Balaji Srinivasan
- NanoScience Technology Center, University of Central Florida, Orlando, FL, USA
| | - Aditya Reddy Kolli
- NanoScience Technology Center, University of Central Florida, Orlando, FL, USA
| | | | | | | | - James J Hickman
- NanoScience Technology Center, University of Central Florida, Orlando, FL, USA Biomolecular Science Center, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, USA
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Shan J, Oshima T, Farre R, Fukui H, Watari J, Miwa H. IL-4 induces columnar-like differentiation of esophageal squamous epithelium through JAK/PI3K pathway: possible role in pathogenesis of Barrett's esophagus. Am J Physiol Gastrointest Liver Physiol 2014; 306:G641-9. [PMID: 24578343 DOI: 10.1152/ajpgi.00386.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Barrett's esophagus is characterized by a distinct Th2-predominant cytokine profile (IL-4) from in vivo or ex vivo evidence. The detailed role of cytokines in Barrett's esophagus, particularly whether Th2 cytokines are causative factors driving metaplastic processes, remains unknown. In this study, air-liquid interface-cultured human esophageal epithelial cells were stimulated by a Th2 cytokine, IL-4, and Th1 cytokines, TNF-α and IL-1β, continuously for 10 days. Barrier function was determined by transepithelial electrical resistance. Morphological changes were investigated by hematoxylin and eosin staining. Keratin profile (keratin 7, 8, 13, and 14) and squamous differentiation markers (involucrin) were investigated by RT-quantitative PCR, Western blotting, and immunohistochemical staining. Pharmacological inhibitors were used to identify the underlying cellular signaling. We report that IL-4, TNF-α, and IL-1β decrease barrier function, but only IL-4 significantly increases cell layers and changes cell morphology. IL-4 time dependently downregulates the expression levels of the squamous cell markers involucrin and keratin 13 and upregulates the expression levels of the columnar cell markers keratin 7 and 8. Neither TNF-α nor IL-1β shows any effect on these indexes. JAK inhibitor I and PI3K inhibitors significantly block the IL-4-induced changes in the levels of keratin 8 and 13. In conclusion, IL-4 inhibits squamous differentiation program of esophageal epithelial cells and induces differentiation toward columnar cells through the JAK/PI3K pathway. Thus IL-4 may be involved in the early stages of Barrett's esophagus development.
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Affiliation(s)
- Jing Shan
- Division of Upper Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
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Shan J, Oshima T, Fukui H, Watari J, Miwa H. Acidic deoxycholic acid and chenodeoxycholic acid induce interleukin-8 production through p38 mitogen-activated protein kinase and protein kinase A in a squamous epithelial model. J Gastroenterol Hepatol 2013; 28:823-8. [PMID: 23425072 DOI: 10.1111/jgh.12139] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/20/2013] [Indexed: 12/17/2022]
Abstract
BACKGROUND AND AIM Immune-mediated mucosal inflammation characterized by the production of interleukin (IL)-8 is associated with the development of gastroesophageal reflux disease. The effects of bile acids, which are major components of reflux fluid, on the production of IL-8 and related mechanisms remain unclear. This study aimed to address these questions using an esophageal stratified squamous epithelial model. METHODS Normal human esophageal epithelial cells were seeded on the Transwell inserts and cultured with the air-liquid interface system to establish the model. Bile acids under different pH conditions were added to the apical compartment to examine their effects on IL-8 production and the underlying cellular signaling. RESULTS Conjugated bile acids under a neutral or acidic condition did not induce IL-8 production, and unconjugated bile acids, deoxycholic acid (DCA), and chenodeoxycholic acid (CDCA) all significantly induced IL-8 production, dose- and time-dependently, only under weakly acid conditions. Inhibition of p38 mitogen-activated protein kinase (p38 MAPK) and protein kinase A (PKA) attenuated the production of IL-8 induced by acidic DCA and CDCA. Inhibition of PKA did not block the bile acid-induced p38 MAPK activation. CONCLUSIONS Compared with conjugated bile acids, the unconjugated bile acids DCA and CDCA are more likely to induce IL-8 production in vivo, especially under weakly acid conditions. This process involves two independent signaling pathways, p38 MAPK and PKA.
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Affiliation(s)
- Jing Shan
- Division of Upper Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
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Shan J, Oshima T, Chen X, Fukui H, Watari J, Miwa H. Trypsin impaired epithelial barrier function and induced IL-8 secretion through basolateral PAR-2: a lesson from a stratified squamous epithelial model. Am J Physiol Gastrointest Liver Physiol 2012; 303:G1105-12. [PMID: 22997195 DOI: 10.1152/ajpgi.00220.2012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Immune-mediated injury by the protease-activated receptor-2-interleukin-8 (PAR-2-IL8) pathway may underlie the development of gastroesophageal reflux disease (GERD). However, the localization of PAR-2 and the mechanism of PAR-2 activation remain unclear. This study aimed to address these questions on an esophageal stratified squamous epithelial model and in the human esophageal mucosa of GERD patients. Normal human esophageal epithelial cells were cultured with the air-liquid interface system to establish the model. SLIGKV-NH2 (PAR-2 synthetic agonist), trypsin (PAR-2 natural activator), and weak acid (pH 4, 5, and 6) were added to either the apical or basolateral compartment to evaluate their effects on transepithelial electrical resistance (TEER) and IL-8 production. PAR-2 localization was examined both in the cell model and biopsies from GERD patients by immunohistochemistry. Apical trypsin stimulation induced IL-8 accompanied by decreased TEER in vitro, whereas the effective concentration from the basolateral side was 10 times lower. SLIGKV-NH2 from basolateral but not apical stimulation induced IL-8 production. Apical weak acid stimulation did not influence TEER or IL-8 production. Immunohistochemistry showed intense reactivity of PAR-2 in the basal and suprabasal layers after stimulation with trypsin. A similar PAR-2 reactivity that was mainly located at the basal and suprabasal layers was detected in GERD patients. In conclusion, the activation of the PAR-2-IL-8 pathway probably occurred at the basal and suprabasal layers, while the esophageal epithelial barrier may influence the activation of PAR-2. Under proton pump inhibitor therapy, refluxed trypsin may remain active and be a potential agent in the pathogenesis of refractory GERD.
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Affiliation(s)
- Jing Shan
- Division of Upper Gastroenterology, Dept. of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
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Chen X, Oshima T, Shan J, Fukui H, Watari J, Miwa H. Bile salts disrupt human esophageal squamous epithelial barrier function by modulating tight junction proteins. Am J Physiol Gastrointest Liver Physiol 2012; 303:G199-208. [PMID: 22575221 DOI: 10.1152/ajpgi.00454.2011] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Reflux of acid and bile acids contributes to epithelial tissue injury in gastro-esophageal reflux disease. However, the influence of refluxed material on human esophageal stratified epithelial barrier function and tight junction (TJ) proteins has not been fully elucidated. Here, we investigated the influence of acid and bile acids on barrier function and TJ protein distribution using a newly developed air-liquid interface (ALI) in vitro culture model of stratified squamous epithelium based on primary human esophageal epithelial cells (HEECs). Under ALI conditions, HEECs formed distinct epithelial layers on Transwell inserts after 7 days of culture. The epithelial layers formed TJ, and the presence of claudin-1, claudin-4, and occludin were detected by immunofluorescent staining. The NP-40-insoluble fraction of these TJ proteins was significantly higher by day 7 of ALI culture. Exposure of HEECs to pH 2, and taurocholic acid (TCA) and glycocholic acid (GCA) at pH 3, but not pH 4, for 1 h decreased transepithelial electrical resistance (TEER) and increased paracellular permeability. Exposure of cell layers to GCA (pH 3) and TCA (pH 3) for 1 h also markedly reduced the insoluble fractions of claudin-1 and -4. We found that deoxycholic acid (pH 7.4 or 6, 1 h) and pepsin (pH 3, 24 h) significantly decreased TEER and increased permeability. Based on these findings, ALI-cultured HEECs represent a new in vitro model of human esophageal stratified epithelium and are suitable for studying esophageal epithelial barrier functions. Using this model, we demonstrated that acid, bile acids, and pepsin disrupt squamous epithelial barrier function partly by modulating TJ proteins. These results provide new insights into understanding the role of TJ proteins in esophagitis.
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Affiliation(s)
- Xin Chen
- Division of Upper Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
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Chen H, Li J, Li H, Hu Y, Tevebaugh W, Yamamoto M, Que J, Chen X. Transcript profiling identifies dynamic gene expression patterns and an important role for Nrf2/Keap1 pathway in the developing mouse esophagus. PLoS One 2012; 7:e36504. [PMID: 22567161 PMCID: PMC3342176 DOI: 10.1371/journal.pone.0036504] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 04/02/2012] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND AND AIMS Morphological changes during human and mouse esophageal development have been well characterized. However, changes at the molecular level in the course of esophageal morphogenesis remain unclear. This study aims to globally profile critical genes and signaling pathways during the development of mouse esophagus. By using microarray analysis this study also aims to determine how the Nrf2/Keap1 pathway regulates the morphogenesis of the esophageal epithelium. METHODS Gene expression microarrays were used to survey gene expression in the esophagus at three critical phases: specification, metaplasia and maturation. The esophagi were isolated from wild-type, Nrf2(-/-), Keap1(-/-), or Nrf2(-/-)Keap1(-/-) embryos or young adult mice. Array data were statistically analyzed for differentially expressed genes and pathways. Histochemical and immunohistochemical staining were used to verify potential involvement of the Wnt pathway, Pparβ/δ and the PI3K/Akt pathway in the development of esophageal epithelium. RESULTS Dynamic gene expression patterns accompanied the morphological changes of the developing esophagus at critical phases. Particularly, the Nrf2/Keap1 pathway had a baseline activity in the metaplasia phase and was further activated in the maturation phase. The Wnt pathway was active early and became inactive later in the metaplasia phase. In addition, Keap1(-/-) mice showed increased expression of Nrf2 downstream targets and genes involved in keratinization. Microarray and immunostaining data also suggested that esophageal hyperkeratosis in the Keap1(-/-) mice was due to activation of Pparβ/δ and the PI3K/Akt pathway. CONCLUSIONS Morphological changes of the esophageal epithelium are associated with dynamic changes in gene expression. Nrf2/Keap1 pathway activity is required for maturation of mouse esophageal epithelium.
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Affiliation(s)
- Hao Chen
- Cancer Research Program, JLC-BBRI, North Carolina Central University, Durham, North Carolina, United States of America
| | - Jianying Li
- Frontier Bioinformatics Solution, LLC, Cary, North Carolina, United States of America
| | - Haiyan Li
- Center for Musculoskeletal Research, University of Rochester, Rochester, New York, United States of America
| | - Yuhui Hu
- Cancer Research Program, JLC-BBRI, North Carolina Central University, Durham, North Carolina, United States of America
| | - Whitney Tevebaugh
- Cancer Research Program, JLC-BBRI, North Carolina Central University, Durham, North Carolina, United States of America
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Jianwen Que
- Department of Biomedical Genetics, University of Rochester, Rochester, New York, United States of America
| | - Xiaoxin Chen
- Cancer Research Program, JLC-BBRI, North Carolina Central University, Durham, North Carolina, United States of America
- Division of Gastroenterology and Hepatology, Center of Esophageal Disease and Swallowing, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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Acid modulates the squamous epithelial barrier function by modulating the localization of claudins in the superficial layers. J Transl Med 2012; 92:22-31. [PMID: 21912379 DOI: 10.1038/labinvest.2011.139] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Acid is a major cause of gastro-esophageal reflux disease. However, the influence of acid on the esophageal stratified epithelial barrier function and tight junction (TJ) proteins is not fully understood. Here, we explore the influence of acid on barrier function and TJ proteins using a newly developed model of the esophageal-like squamous epithelial cell layers that employs an air-liquid interface (ALI) system. Barrier function was determined by measuring trans-epithelial electrical resistance (TEER) and diffusion of paracellular tracers. TJ-related protein (claudin-1, claudin-4, occludin and ZO-1) expression and localization was examined by immunofluorescent staining, and by western blotting of 1% NP-40 soluble and insoluble fractions. We also examined the influence of acid (pH 2-4) on the barrier created by these cells. The in vitro ALI culture system showed a tight barrier (1500-2500 Ω·cm(2)) with the expression of claudin-1, claudin-4, occludin and ZO-1 in the superficial layers. Claudin-1, claudin-4, occludin and ZO-1 were detected as dots and whisker-like lines in the superficial layers, and as a broad line in the suprabasal layers. These localization patterns are similar to those in the human esophagus. On day 7 under ALI culture, TJ proteins were detected in the superficial layers with functional properties, including decreased permeability and increased TEER. Dilated intercellular spaces were detected at the suprabasal cell layers even under the control conditions of ALI cells. pH 2 acid on the apical side significantly reduced the TEER in ALI-cultured cells. This decrease in TEER by the acid was in parallel with the decreased amount of detergent-insoluble claudin-4. Claudin-4 delocalization was confirmed by immunofluorescent staining. In conclusion, TJs are located in the superficial layers of the esophagus, and acid stimulation disrupts barrier function, at least in part by modulating the amount and localization of claudin-4 in the superficial layers.
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Chen X, Oshima T, Tomita T, Fukui H, Watari J, Matsumoto T, Miwa H. Acidic bile salts modulate the squamous epithelial barrier function by modulating tight junction proteins. Am J Physiol Gastrointest Liver Physiol 2011; 301:G203-9. [PMID: 21617116 DOI: 10.1152/ajpgi.00096.2011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Experimental models for esophageal epithelium in vitro either suffer from poor differentiation or complicated culture systems. An air-liquid interface system with normal human bronchial epithelial cells can serve as a model of esophageal-like squamous epithelial cell layers. Here, we explore the influence of bile acids on barrier function and tight junction (TJ) proteins. The cells were treated with taurocholic acid (TCA), glycocholic acid (GCA), or deoxycholic acid (DCA) at different pH values, or with pepsin. Barrier function was measured by transepithelial electrical resistance (TEER) and the diffusion of paracellular tracers (permeability). The expression of TJ proteins, including claudin-1 and claudin-4, was examined by Western blotting of 1% Nonidet P-40-soluble and -insoluble fractions. TCA and GCA dose-dependently decreased TEER and increased paracellular permeability at pH 3 after 1 h. TCA (4 mM) or GCA (4 mM) did not change TEER and permeability at pH 7.4 or pH 4. The combination of TCA and GCA at pH 3 significantly decreased TEER and increased permeability at lower concentrations (2 mM). Pepsin (4 mg/ml, pH 3) did not have any effect on barrier function. DCA significantly decreased the TEER and increased permeability at pH 6, a weakly acidic condition. TCA (4 mM) and GCA (4 mM) significantly decreased the insoluble fractions of claudin-1 and claudin-4 at pH 3. In conclusion, acidic bile salts disrupted the squamous epithelial barrier function partly by modulating the amounts of claudin-1 and claudin-4. These results provide new insights for understanding the role of TJ proteins in esophagitis.
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Affiliation(s)
- Xin Chen
- Division of Upper Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
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