TRPV1-Induced ATP Production by Human Esophageal Epithelial Cells Mediates Release of CGRP and Substance P From Esophageal Mucosa

Human esophageal epithelium is continuously exposed to physical stimuli or to gastric acid that sometimes causes inflammation of the mucosa. Transient receptor potential vanilloid 1 (TRPV1) is a nociceptive, Ca2+-selective ion channel activated by capsaicin, heat, and protons. It has been reported that activation of TRPV1 expressed in esophageal mucosa is involved in gastroesophageal reflux disease (GERD) or in nonerosive GERD symptoms. In this study, we examined the expression and function of TRPV1 in the human esophageal epithelial cell line Het1A, focusing in particular on the role of oxidative stress. Interleukin-8 (IL-8) secreted by Het1A cells upon stimulation by capsaicin or acid with/without 4-hydroxy-2-nonenal (HNE) was measured by ELISA. Following capsaicin stimulation, the intracellular production of reactive oxygen species (ROS) was determined using a redox-sensitive fluorogenic probe, and ROS- and HNE-modified proteins were determined by Western blotting using biotinylated cysteine and anti-HNE antibody, respectively. HNE modification of TRPV1 proteins was further investigated by immunoprecipitation after treatment with synthetic HNE. Capsaicin and acid induced IL-8 production in Het1A cells, and this production was diminished by antagonists of TRPV1. Capsaicin also significantly increased the production of intracellular ROS and ROS- or HNE-modified proteins in Het1A cells. Moreover, IL-8 production in capsaicin-stimulated Het1A cells was enhanced by synthetic HNE treatment. Immunoprecipitation studies revealed that TRPV1 was modified by HNE in synthetic HNE-stimulated Het1A cells. We concluded that TRPV1 functions in chemokine production in esophageal epithelial cells, and this function may be regulated by ROS via posttranslational modification of TRPV1.

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ATP: a mediator for HCl-induced TRPV1 activation in esophageal mucosa

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00336.2011 ◽

2011 ◽

Vol 301 (6) ◽

pp. G1075-G1082 ◽

Cited By ~ 22

Author(s):

Jie Ma ◽

Annamaria Altomare ◽

Florian Rieder ◽

Jose Behar ◽

Piero Biancani ◽

...

Keyword(s):

Epithelial Cells ◽

Platelet Activating Factor ◽

Atp Release ◽

Repeated Exposure ◽

Epithelial Cell Line ◽

Esophageal Mucosa ◽

Coa Transferase ◽

Paf Antagonists ◽

Esophageal Epithelial Cells ◽

Trpv1 Antagonist

In esophageal mucosa, HCl causes TRPV1-mediated release of calcitonin gene-related peptide (CGRP) and substance P (SP) from submucosal neurons and of platelet-activating factor (PAF) from epithelial cells. CGRP and SP release was unaffected by PAF antagonists but reduced by the purinergic antagonist suramin. ATP caused CGRP and SP release from esophageal mucosa, confirming a role of ATP in the release. The human esophageal epithelial cell line HET-1A was used to identify epithelial cells as the site of ATP release. HCl caused ATP release from HET-1A, which was reduced by the TRPV1 antagonist 5-iodoresiniferatoxin. Real-time PCR demonstrated the presence of mRNA for several P2X and P2Y purinergic receptors in epithelial cells. HCl also increased activity of lyso-PAF acetyl-CoA transferase (lyso-PAF AT), the enzyme responsible for production of PAF. The increase was blocked by suramin. ATP caused a similar increase, confirming ATP as a mediator for the TRPV1-induced increase in enzyme activity. Repeated exposure of HET-1A cells to HCl over 2 days caused upregulation of mRNA and protein expression for lyso-PAF AT. Suramin blocked this response. Repeated exposure to ATP caused a similar mRNA increase, confirming ATP as a mediator for upregulation of the enzyme. Thus, HCl-induced activation of TRPV1 causes ATP release from esophageal epithelial cells that causes release of CGRP and SP from esophageal submucosal neurons and activation of lyso-PAF AT, the enzyme responsible for the production of PAF in epithelial cells. Repeated application of HCl or of ATP causes upregulation of lyso-PAF AT in epithelial cells.

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HCl-activated neural and epithelial vanilloid receptors (TRPV1) in cat esophageal mucosa

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.90386.2008 ◽

2009 ◽

Vol 297 (1) ◽

pp. G135-G143 ◽

Cited By ~ 30

Author(s):

Ling Cheng ◽

Suzanne de la Monte ◽

Jie Ma ◽

Jie Hong ◽

Ming Tong ◽

...

Keyword(s):

Substance P ◽

Epithelial Cells ◽

Transient Receptor Potential ◽

Platelet Activating Factor ◽

Circular Muscle ◽

Receptor Potential ◽

Transient Receptor Potential Channel ◽

Esophageal Mucosa ◽

Transient Receptor ◽

Krebs Buffer

To test whether transient receptor potential channel vanilloid subfamily member-1 (TRPV1) mediates acid-induced inflammation in the esophagus, a tubular segment of esophageal mucosa was tied at both ends, forming a sac. The sac was filled with 0.01 N HCl (or Krebs buffer for control) and kept in oxygenated Krebs buffer at 37°C. The medium around the sac (supernatant) was collected after 3 h. Supernatant of the HCl-filled sac abolished contraction of esophageal circular muscle strips in response to electric field stimulation. Contraction was similarly abolished by supernatant of mucosal sac filled with the TRPV1 agonist capsaicin (10−6 M). These effects were reversed by the selective TRPV1 antagonist 5′-iodoresiniferatoxin (IRTX) and by the platelet-activating factor (PAF) receptor antagonist CV9388. Substance P and CGRP levels in mucosa and in supernatant increased in response to HCl, and these increases were abolished by IRTX and by tetrodotoxin (TTX) but not affected by CV9388, indicating that substance P and CGRP are neurally released and PAF independent. In contrast, the increase in PAF was blocked by IRTX but not by TTX. Presence of TRPV1 receptor was confirmed by RT-PCR and by Western blot analysis in whole mucosa and in esophageal epithelial cells enzymatically isolated and sorted by flow cytometry or immunoprecipitated with cytokeratin antibodies. In epithelial cells PAF increased in response to HCl, and the increase was abolished by IRTX. We conclude that HCl-induced activation of TRPV1 receptors in esophageal mucosa causes release of substance P and CGRP from neurons and release of PAF from epithelial cells.

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HCl-induced and ATP-dependent upregulation of TRPV1 receptor expression and cytokine production by human esophageal epithelial cells

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00097.2012 ◽

2012 ◽

Vol 303 (5) ◽

pp. G635-G645 ◽

Cited By ~ 29

Author(s):

Jie Ma ◽

Annamaria Altomare ◽

Michele Guarino ◽

Michele Cicala ◽

Florian Rieder ◽

...

Keyword(s):

Epithelial Cells ◽

Transient Receptor Potential ◽

Inflammatory Responses ◽

Atp Release ◽

Erosive Esophagitis ◽

Receptor Expression ◽

Epithelial Cell Line ◽

Esophageal Mucosa ◽

Proinflammatory Mediators ◽

Esophageal Epithelial Cells

The pathogenesis of gastroesophageal reflux disease (GERD) remains elusive, but recent evidence suggests that early secretion of inflammatory cytokines and chemokines by the mucosa leads to influx of immune cells followed by tissue damage. We previously showed that exposure of esophageal mucosa to HCl causes ATP release, resulting in activation of acetyl-CoA:1- O-alkyl- sn-glycero-3-phosphocholine acetyltransferase (lyso-PAF AT), the enzyme responsible for the production of platelet-activating factor (PAF). In addition, HCl causes release of IL-8 from the esophageal mucosa. We demonstrate that esophageal epithelial cells secrete proinflammatory mediators in response to HCl and that this response is mediated by ATP. Monolayers of the human esophageal epithelial cell line HET-1A were exposed to acidified cell culture medium (pH 5) for 12 min, a total of seven times over 48 h, to simulate the recurrent acid exposure clinically occurring in GERD. HCl upregulated mRNA and protein expression for the acid-sensing transient receptor potential cation channel, subfamily vanilloid member 1 (TRPV1), lyso-PAF AT, IL-8, eotaxin-1, -2, and -3, macrophage inflammatory protein-1α, and monocyte chemoattractant protein-1. The chemokine profile secreted by HET-1A cells in response to repeated HCl exposure parallels similar findings in erosive esophagitis patients. In HET-1A cells, the TRPV1 agonist capsaicin reproduced these findings for mRNA of the inflammatory mediators lyso-PAF AT, IL-8, and eotaxin-1. These effects were blocked by the TRPV1 antagonists iodoresiniferatoxin and JNJ-17203212. These effects were imitated by direct application of ATP and blocked by the nonselective ATP antagonist suramin. We conclude that HCl/TRPV-induced ATP release upregulated secretion of various chemoattractants by esophageal epithelial cells. These chemoattractants are selective for leukocyte subsets involved in acute inflammatory responses and allergic inflammation. The data support the validity of HET-1A cells as a model of the response of the human esophageal mucosa in GERD.

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Effect of Calcium on the Growth and Differentiation of Cultured Rat Esophageal Epithelial Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053383 ◽

1982 ◽

Vol 40 ◽

pp. 132-133

Author(s):

W.T. Gunning ◽

M.R. Marino ◽

M.S. Babcock ◽

G.D. Stoner

Keyword(s):

Epithelial Cells ◽

Cell Types ◽

Replication Rate ◽

Enzymatic Dissociation ◽

Growth Assay ◽

Epidermal Growth ◽

Fetal Bovine ◽

Esophageal Epithelial Cells ◽

Cellular Replication

The role of calcium in modulating cellular replication and differentiation has been described for various cell types. In the present study, the effects of Ca++ on the growth and differentiation of cultured rat esophageal epithelial cells was investigated.Epithelial cells were isolated from esophagi taken from 8 week-old male CDF rats by the enzymatic dissociation method of Kaighn. The cells were cultured in PFMR-4 medium supplemented with 0.25 mg/ml dialyzed fetal bovine serum, 5 ng/ml epidermal growth factor, 10-6 M hydrocortisone 10-6 M phosphoethanolamine, 10-6 M ethanolamine, 5 pg/ml insulin, 5 ng/ml transferrin, 10 ng/ml cholera toxin and 50 ng/ml garamycin at 36.5°C in a humidified atmosphere of 3% CO2 in air. At weekly intervals, the cells were subcultured with a solution containing 1% polyvinylpyrrolidone, 0.01% EGTA, and 0.05% trypsin. After various passages, the replication rate of the cells in PFMR-4 medium containing from 10-6 M to 10-3 M Ca++ was determined using a clonal growth assay.

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