905 TRPA1 in Mast Cell Activation-Induced Mechano-Hyperexcitability of Vagal Afferent C Fibers in Guinea Pig Esophagus: A Novel Mechanism of Visceral Peripheral Sensitization

Sensitization of esophageal sensory afferents by inflammatory mediators plays an important role in esophageal nociception. We have shown esophageal mast cell activation induces long-lasting mechanical hypersensitivity in vagal nodose C-fibers. However, the roles of mast cell mediators and downstream ion channels in this process are unclear. Mast cell tryptase via protease-activated receptor 2 (PAR2)-mediated pathways sensitizes sensory nerves and induces hyperalgesia. Transient receptor potential A1 (TRPA1) plays an important role in mechanosensory transduction and nociception. Here we tested the hypothesis that mast cell activation via a PAR2-dependent mechanism sensitizes TRPA1 to induce mechanical hypersensitivity in esophageal vagal C-fibers. The expression profiles of PAR2 and TRPA1 in vagal nodose ganglia were determined by immunostaining, Western blot, and RT-PCR. Extracellular recordings from esophageal nodose neurons were performed in ex vivo guinea pig esophageal-vagal preparations. Action potentials evoked by esophageal distention and chemical perfusion were compared. Both PAR2 and TRPA1 expressions were identified in vagal nodose neurons by immunostaining, Western blot, and RT-PCR. Ninety-one percent of TRPA1-positive neurons were of small and medium diameters, and 80% coexpressed PAR2. Esophageal mast cell activation significantly enhanced the response of nodose C-fibers to esophageal distension (mechanical hypersensitivity). This was mimicked by PAR2-activating peptide, which sustained for 90 min after wash, but not by PAR2 reverse peptide. TRPA1 inhibitor HC-030031 pretreatment significantly inhibited mechanical hypersensitivity induced by either mast cell activation or PAR2 agonist. Collectively, our data provide new evidence that sensitizing TRPA1 via a PAR2-dependent mechanism plays an important role in mast cell activation-induced mechanical hypersensitivity of vagal nodose C-fibers in guinea pig esophagus.

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Role of prostaglandin D2 in mast cell activation-induced sensitization of esophageal vagal afferents

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00448.2012 ◽

2013 ◽

Vol 304 (10) ◽

pp. G908-G916 ◽

Cited By ~ 11

Author(s):

Shizhong Zhang ◽

Gintautas Grabauskas ◽

Xiaoyin Wu ◽

Moon Kyung Joo ◽

Andrea Heldsinger ◽

...

Keyword(s):

Mast Cell ◽

Action Potential ◽

Cell Activation ◽

Vagal Afferents ◽

Mast Cell Activation ◽

Lipid Mediator ◽

Prostaglandin D2 ◽

Patch Clamp Recording ◽

C Fibers ◽

Ganglion Neurons

Sensitization of esophageal afferents plays an important role in esophageal nociception, but the mechanism is less clear. Our previous studies demonstrated that mast cell (MC) activation releases the preformed mediators histamine and tryptase, which play important roles in sensitization of esophageal vagal nociceptive C fibers. PGD2 is a lipid mediator released by activated MCs. Whether PGD2 plays a role in this sensitization process has yet to be determined. Expression of the PGD2 DP1 and DP2 receptors in nodose ganglion neurons was determined by immunofluorescence staining, Western blotting, and RT-PCR. Extracellular recordings were performed in ex vivo esophageal-vagal preparations. Action potentials evoked by esophageal distension were compared before and after perfusion of PGD2, DP1 and DP2 receptor agonists, and MC activation, with or without pretreatment with antagonists. The effect of PGD2 on 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI)-labeled esophageal nodose neurons was determined by patch-clamp recording. Our results demonstrate that DP1 and DP2 receptor mRNA and protein were expressed mainly in small- and medium-diameter neurons in nodose ganglia. PGD2 significantly increased esophageal distension-evoked action potential discharges in esophageal nodose C fibers. The DP1 receptor agonist BW 245C mimicked this effect. PGD2 directly sensitized DiI-labeled esophageal nodose neurons by decreasing the action potential threshold. Pretreatment with the DP1 receptor antagonist BW A868C significantly inhibited PGD2 perfusion- or MC activation-induced increases in esophageal distension-evoked action potential discharges in esophageal nodose C fibers. In conclusion, PGD2 plays an important role in MC activation-induced sensitization of esophageal nodose C fibers. This adds a novel mechanism of visceral afferent sensitization.

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Intraluminal acid activates esophageal nodose C fibers after mast cell activation

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00142.2013 ◽

2014 ◽

Vol 306 (3) ◽

pp. G200-G207 ◽

Cited By ~ 14

Author(s):

Shizhong Zhang ◽

Zhenyu Liu ◽

Andrea Heldsinger ◽

Chung Owyang ◽

Shaoyong Yu

Keyword(s):

Mast Cell ◽

Action Potential ◽

Cell Activation ◽

Ex Vivo ◽

Mast Cell Activation ◽

Noncardiac Chest Pain ◽

Acid Infusion ◽

C Fibers ◽

Ganglion Neurons ◽

Zona Occludens

Acid reflux in the esophagus can induce esophageal painful sensations such as heartburn and noncardiac chest pain. The mechanisms underlying acid-induced esophageal nociception are not clearly understood. In our previous studies, we characterized esophageal vagal nociceptive afferents and defined their responses to noxious mechanical and chemical stimulation. In the present study, we aim to determine their responses to intraluminal acid infusion. Extracellular single-unit recordings were performed in nodose ganglion neurons with intact nerve endings in the esophagus using ex vivo esophageal-vagal preparations. Action potentials evoked by esophageal intraluminal acid perfusion were compared in naive and ovalbumin (OVA)-challenged animals, followed by measurements of transepithelial electrical resistance (TEER) and the expression of tight junction proteins (zona occludens-1 and occludin). In naive guinea pigs, intraluminal infusion with either acid (pH = 2–3) or capsaicin did not evoke an action potential discharge in esophageal nodose C fibers. In OVA-sensitized animals, following esophageal mast cell activation by in vivo OVA inhalation, intraluminal acid infusion for about 20 min started to evoke action potential discharges. This effect is further confirmed by selective mast cell activation using in vitro tissue OVA challenge in esophageal-vagal preparations. OVA inhalation leads to decreased TEER and zona occludens-1 expression, suggesting an impaired esophageal epithelial barrier function after mast cell activation. These data for the first time provide direct evidence of intraluminal acid-induced activation of esophageal nociceptive C fibers and suggest that mast cell activation may make esophageal epithelium more permeable to acid, which subsequently may increase esophageal vagal nociceptive C fiber activation.

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Novel airway smooth muscle–mast cell interactions and a role for the TRPV4-ATP axis in non-atopic asthma

European Respiratory Journal ◽

10.1183/13993003.01458-2019 ◽

2020 ◽

Vol 56 (1) ◽

pp. 1901458 ◽

Cited By ~ 2

Author(s):

Sara J. Bonvini ◽

Mark A. Birrell ◽

Eric Dubuis ◽

John J. Adcock ◽

Michael A. Wortley ◽

...

Keyword(s):

Mast Cell ◽

Smooth Muscle ◽

Mast Cells ◽

Guinea Pig ◽

Airway Smooth Muscle ◽

Cell Activation ◽

Transient Receptor Potential ◽

Atopic Asthma ◽

Mast Cell Activation ◽

Tracheal Tissue

Mast cell–airway smooth muscle (ASM) interactions play a major role in the immunoglobulin (Ig)E- dependent bronchoconstriction seen in asthma but less is known about IgE-independent mechanisms of mast cell activation. Transient receptor potential cation channel, subfamily V, member 4 (TRPV4) activation causes contraction of human ASM via the release of cysteinyl leukotrienes (cysLTs) but the mechanism is unknown. The objective of the present study was to investigate a role for IgE-independent, mast cell–ASM interaction in TRPV4-induced bronchospasm.Bronchoconstriction was measured in anaesthetised guinea pigs and contraction of human and guinea-pig airway tissue assessed using isometric tension measurements. Increases in intracellular [Ca2+] were imaged using the Ca2+-sensitive dye FURA2, and time-lapse ptychography was utilised as a surrogate for contraction of ASM cells.The TRPV4 agonist GSK1016790A caused contraction in vivo in the guinea pig, and in human and guinea-pig tracheal tissue, which was inhibited by the TRPV4 antagonist GSK2193874. GSK1016790A increased [Ca2+]i and released ATP in human ASM cells without causing contraction. TRPV4 and ATP evoked contraction in isolated tracheal tissue but co-culture experiments indicated a requirement for human lung mast cells. Expression profiling and pharmacological studies demonstrated that mast cell activation was dependent upon ATP activating the P2X4 receptor. Trypsin was shown to evoke contraction of tracheal tissue via activation of PAR-2-TRPV4-ATP-cysLT axis indicating the potential disease relevance of this signalling pathway.TRPV4 activation increases [Ca2+]i and releases ATP from ASM cells triggering P2X4-dependent release of cysLTs from mast cells resulting in ASM contraction. This study delineates a novel mast cell–ASM interaction and TRPV4 as a driver of IgE-independent mast cell-dependent bronchospasm.

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