Nasal mucosa sensitization with toluene diisocyanate (TDI) increases preprotachykinin A (PPTA) and preproCGRP mRNAs in guinea pig trigeminal ganglion neurons

Effects of irradiation with narrowband-ultraviolet B on up-regulation of histamine H1 receptor mRNA and induction of apoptosis in HeLa cells and nasal mucosa of rats

Narrowband-ultraviolet B (NB-UVB) phototherapy is used for the treatment of atopic dermatitis. Previously, we reported that irradiation with 200 mJ/cm² of 310 nm NB-UVB suppressed phorbol-12-myristate-13-acetate (PMA)-induced up-regulation of histamine H₁ receptor (H1R) gene expression without induction of apoptosis in HeLa cells. However, the effect of NB-UVB irradiation on nasal symptoms is still unclear. Here, we show that low dose irradiation with 310 nm NB-UVB alleviates nasal symptoms in toluene 2,4-diisocyanate (TDI)-sensitized allergy model rats. Irradiation with 310 nm NB-UVB suppressed PMA-induced H1R mRNA up-regulation in HeLa cells dose-dependently at doses of 75-200 mJ/cm² and reversibly at a dose of 150 mJ/cm² without induction of apoptosis. While, at doses of more than 200 mJ/cm², irradiation with 310 nm NB-UVB induced apoptosis. Western blot analysis showed that the suppressive effect of NB-UVB irradiation on H1R gene expression was through the inhibition of ERK phosphorylation. In TDI-sensitized rat, intranasal irradiation with 310 nm NB-UVB at an estimated dose of 100 mJ/cm² once a day for three days suppressed TDI-induced sneezes and up-regulation of H1R mRNA in nasal mucosa without induction of apoptosis. These findings suggest that repeated intranasal irradiation with low dose of NB-UVB could be clinically used as phototherapy of AR.

Gastrin-Releasing Peptide Is Involved in the Establishment of Allergic Rhinitis in Mice

OBJECTIVE

Gastrin-releasing peptide (GRP) is a neuropeptide that targets transmembrane-type receptors. Its role in allergic rhinitis (AR) has yet to be investigated. The present study utilized the nasal mucosa of AR model mice to examine GRP and GRP receptor (GRPR) expression levels, localization, and other factors to evaluate their role in AR pathology.

STUDY DESIGN

In vivo study in an animal model.

METHODS

GRP and GRPR expression levels were examined in three different AR models established in BALB/c mice. In addition, a GRPR antagonist (RC-3095) was administered to AR mice to investigate its effect. The distribution of GRPR expression on mast cells in the nasal mucosa with AR was examined. Finally, we investigated the inhibitory effect of RC-3095 on allergy symptoms induced by histamine.

RESULTS

GRP and GRPR were highly expressed in the nasal mucosal epithelium and interstitial tissues surrounding the nasal glands in AR groups according to immunostaining. GRP and GRPR expression as determined by western blotting increased in the nasal mucosa as the degree of nasal sensitization increased. In addition, the average counts of sneezing and nasal rubbing after treatment in the AR + RC-3095 group were significantly lower than those in the AR + nasal saline group. Mast cells often colocalized with GRPR around nasal glands. Moreover, RC-3095 was effective in reducing sneezing induced by histamine.

CONCLUSION

The GRP-GRPR system is likely to be involved in allergic inflammation. This system may represent a novel therapeutic target for refractory AR.

LEVEL OF EVIDENCE

NA. Laryngoscope, E377-E384, 2018.

Nasal allergen deposition leads to conjunctival mast cell degranulation in allergic rhinoconjunctivitis

BACKGROUND

The naso-ocular interaction in allergic rhinoconjunctivitis is well recognized from epidemiological, clinical, and experimental observations. The precise mechanisms remain incompletely understood. A new mouse model of allergic rhinoconjunctivitis was used to investigate the contribution of mast cells and trigeminal ganglia activation to conjunctival (conj.) inflammation after nasal allergen provocation.

METHODS

Sensitized mice were exposed to ovalbumin (OVA) via the nose and/or conjunctiva, and conj. homogenates were analyzed for histamine and substance P (using ELISA) and by eosinophil peroxidase (EPO) and beta-hexosaminidase assays. The conj. effects of nasal allergen deposition were compared with those induced by the mast cell activator C48/80 and with pretreatment of the mast cell stabilizer ketotifen or the transient receptor potential channel receptor (TRP) agonist capsaicin. Protachykinin 1 (TAC1) expression was quantified in the trigeminal ganglia using real time polymerase chain reaction.

RESULTS

At 1 hour after nasal application of OVA, increased conj. levels of beta-hexosaminidase (0.68 ± 0.03 nm versus 0.56 ± 0.02 nm; p = 0.02), histamine (751.1 ± 52.17 ng/mL versus 546.3 ± 76.91 ng/mL; p = 0.05), and EPO (0.66 ± 0.09 nm versus 0.37 ± 0.03 nm; p = 0.02) were detected compared with saline. Higher levels of TAC1 expression were found in the trigeminal ganglia at 24 hours after OVA application (1326 ± 255 versus 687.5 ± 90.77 TAC1/beta-actin; p = 0.04). Nasal challenge with C48/80 increased substance P and beta-hexosaminidase levels in the conjunctiva, as well as TAC1 expression. Pretreatment with ketotifen resulted in lower levels of substance P as well as TAC1 expression. Destruction of sensory nerves in the nose by capsaicin reduced the OVA-induced conj. levels of substance P, histamine, and beta-hexosaminidase.

CONCLUSION

Nasal allergen deposition in sensitized mice induced trigeminal TAC1 expression and conj. mast cell degranulation. These data represent a significant step forward in understanding the close interaction between nasal and conj. inflammation in allergy.

Albizia lebbeck suppresses histamine signaling by the inhibition of histamine H1 receptor and histidine decarboxylase gene transcriptions

Histamine plays major roles in allergic diseases and its action is mediated mainly by histamine H(1) receptor (H1R). We have demonstrated that histamine signaling-related H1R and histidine decarboxylase (HDC) genes are allergic diseases sensitive genes and their expression level affects severity of the allergic symptoms. Therefore, compounds that suppress histamine signaling should be promising candidates as anti-allergic drugs. Here, we investigated the effect of the extract from the bark of Albizia lebbeck (AL), one of the ingredients of Ayruvedic medicines, on H1R and HDC gene expression using toluene-2,4-diisocyanate (TDI) sensitized allergy model rats and HeLa cells expressing endogenous H1R. Administration of the AL extract significantly decreased the numbers of sneezing and nasal rubbing. Pretreatment with the AL extract suppressed TDI-induced H1R and HDC mRNA elevations as well as [(3)H]mepyramine binding, HDC activity, and histamine content in the nasal mucosa. AL extract also suppressed TDI-induced up-regulation of IL-4, IL-5, and IL-13 mRNA. In HeLa cells, AL extract suppressed phorbol-12-myristate-13-acetate- or histamine-induced up-regulation of H1R mRNA. Our data suggest that AL alleviated nasal symptoms by inhibiting histamine signaling in TDI-sensitized rats through suppression of H1R and HDC gene transcriptions. Suppression of Th2-cytokine signaling by AL also suggests that it could affect the histamine-cytokine network.

Suplatast tosilate inhibits histamine signaling by direct and indirect down-regulation of histamine H1 receptor gene expression through suppression of histidine decarboxylase and IL-4 gene transcriptions

Allergic rhinitis (AR) is an inflammatory disorder typified by symptoms such as sneezing, congestion, and rhinorrhea. Histamine plays important roles in eliciting AR symptoms. Up-regulation of the histamine H(1) receptor (H1R) and histidine decarboxylase (HDC) mRNAs was observed in AR patients. Th2 cytokines are also involved in the pathogenesis of AR. We examined the effect of suplatast tosilate on nasal symptoms, and H1R, HDC, and IL-4 gene expression using toluene-2,4-diisocyanate (TDI)-sensitized rats and HeLa cells expressing endogenous H1R. Provocation with TDI increased nasal symptoms, HDC activity, the histamine content of nasal lavage fluid, and the expression of H1R, HDC, and IL-4 mRNAs in TDI-sensitized rats. Pretreatment with suplatast for 2 wk significantly suppressed TDI-induced nasal symptoms and elevation of H1R, HDC, and IL-4 mRNAs. Suplatast also suppressed HDC activity in the nasal mucosa and the histamine content of the nasal lavage fluid. Bilateral injection of IL-4 into the nasal cavity of normal rats up-regulated H1R mRNA, while intranasal application of histamine up-regulated IL-4 mRNA. Suplatast suppressed IL-4-induced up-regulation of H1R mRNA in HeLa cells. However, it did not inhibit histamine-induced H1R mRNA elevation. These results suggest that suplatast alleviates nasal symptoms by inhibiting histamine signaling in TDI-sensitized rats through the suppression of histamine- and IL-4-induced H1R gene expression by the inhibitions of HDC and IL-4 gene transcriptions, respectively.

Kujin suppresses histamine signaling at the transcriptional level in toluene 2,4-diisocyanate-sensitized rats

Kujin, the dried root of Sophorae flavescensis, has been used in Chinese folklore medicine against allergy. Evaluation of its anti-allergic potential as well as its mechanism of action has rarely been established. We investigated the effect of Kujin on toluene-2,4-diisocyanate (TDI)-induced allergic behavior and related histamine signaling including mRNA levels of histamine H(1) receptor (H1R) and histidine decarboxylase (HDC), H1R and HDC activities, and histamine content in rat nasal mucosa. We also investigated the effect of Kujin on the mRNA levels of helper T cell type 2 (Th2)-cytokine genes closely related to histamine signaling. TDI provocation caused acute allergic symptoms accompanied with up-regulations of H1R and HDC mRNAs and increases in HDC activity, histamine content, and [(3)H]mepyramine binding activity in the nasal mucosa, all of which were significantly suppressed by pretreatment with Kujin for 3 weeks. Kujin also suppressed the TDI-induced IL-4 and IL-5 mRNA elevations. These data suggest that oral administration of Kujin showed anti-allergic activity through suppression of histamine signaling by the inhibition of TDI-induced H1R and HDC mRNA elevations followed by decrease in H1R, HDC protein level, and histamine content in the nasal mucosa of TDI-sensitized rats. Suppression of Th2-cytokine signaling by Kujin also suggests that it could affect the histamine-cytokine network.

Repeated pre-treatment with antihistamines suppresses [corrected] transcriptional up-regulations of histamine H(1) receptor and interleukin-4 genes in toluene-2,4-diisocyanate-sensitized rats

Antihistamines are effective for treatment of seasonal nasal allergy. Recently, prophylactic treatment with antihistamines in patients with pollinosis was reported to be more effective when started before the pollen season. The administration with antihistamines from 2 to 6 weeks before onset of the pollen season is recommended for management of allergic rhinitis in Japan. To determine the reason for the effectiveness of prophylactic treatment with antihistamines, the effects of repeated pre-treatment with antihistamines before provocation with toluene 2,4-diisocyanate (TDI) on their nasal allergy-like behavior and up-regulations of histamine H(1) receptors (H1R) and interleukin (IL)-4 mRNAs in their nasal mucosa were examined. Provocation with TDI induced sneezing and up-regulations of H1R and IL-4 mRNAs in the nasal mucosa of TDI-sensitized rats. Repeated pre-treatments with antihistamines including epinastine, olopatadine, or d-chlorpheniramine for 1 to 5 weeks before provocation with TDI suppressed TDI-induced sneezing and the up-regulations of H1R and IL-4 mRNAs in the nasal mucosa more than their administrations once or for 3 days before TDI provocation. Our data indicate that repeated pre-treatment with antihistamines before provocation with TDI is more effective than their single treatment in reducing nasal allergy-like behavior by causing additional suppression of up-regulations of H1R and IL-4 mRNAs in the nasal mucosa.

Transient receptor potential ankyrin 1 mediates toluene diisocyanate-evoked respiratory irritation

Toluene diisocyanate (TDI), a reactive, hazardous irritant, causes respiratory symptoms such as cough, rhinitis, dyspnea, and chest tightness in exposed workers. Although previous animal studies have shown that TDI causes respiratory reflexes that are abolished by desensitization of capsaicin-sensitive sensory nerves, the specific molecular identity of the transducer(s) responsible for sensing this noxious stimulus has, to date, remained elusive. Recent studies have demonstrated that transient receptor potential ankyrin 1 (TRPA1), an ion channel largely restricted to a subset of capsaicin-sensitive sensory nerves, functions as a transducer capable of initiating reflex responses to many reactive chemical stimuli. We therefore hypothesized that TRPA1 is the primary molecular transducer through which TDI causes sensory nerve activation and respiratory reflexes. Consistent with this hypothesis, TDI activated TRPA1, but not the capsaicin-sensitive transient receptor potential vanilloid 1 channel, in heterologous expression systems. TDI also activated a subset of dissociated trigeminal sensory neurons from wild-type but not TRPA1-deficient mice. In vivo, TDI mimicked known TRPA1 agonists by causing a pronounced decrease in breathing rate, indicative of respiratory sensory irritation, and this reflex was abolished in TRPA1-deficient mice. Together, our data suggest that TDI causes sensory nerve activation and airway sensory irritation via the activation of the ion channel, TRPA1.

Dexamethasone suppresses histamine synthesis by repressing both transcription and activity of HDC in allergic rats

BACKGROUND

Histamine synthesized by histidine decarboxylase (HDC) from L-histidine is a major chemical mediator in the development of nasal allergy which is characterized by nasal hypersensitivity. However the regulatory mechanism of histamine synthesis by HDC remains to be elucidated. The objectives of the present study were to examine the changes of histamine content, HDC activity and HDC mRNA expression in the nasal mucosa of allergy model rats sensitized by the exposure to toluene diisocyanate (TDI) and to investigate the effect of dexamethasone on the above mentioned allergic parameters.

METHODS

Rats were sensitized and provocated by TDI and the nasal allergy-like behaviors were scored during a 10 minute period after provocation. Histamine content and HDC activity in the nasal mucosa were determined using fluorometric high performance liquid chromatography. The expression of HDC mRNA in nasal mucosa was determined using real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

In TDI-sensitized rats, nasal allergy-like behaviors such as sneezing and watery rhinorrhea were induced. Histamine content, HDC activity and HDC mRNA expression in nasal mucosa were also significantly increased after TDI provocation. Pretreatment with dexamethasone significantly suppressed nasal allergy-like behaviors, up-regulation of histamine content, HDC activity and HDC mRNA induced by TDI in TDI-sensitized rats.

CONCLUSIONS

These findings indicate that increased synthesis of histamine through up-regulation of HDC gene expression and HDC activity in nasal mucosa plays an important role in the development of nasal hypersensitivity. Repression of HDC gene expression and HDC activity by dexamethasone may underlie its therapeutic effect in the treatment of allergy.

Is occupational asthma to diisocyanates a non-IgE-mediated disease?

BACKGROUND

Exposure to diisocyanates in the workplace is an important cause of occupational asthma. The majority of patients with diisocyanate-induced asthma have no detectable diisocyanate-specific IgE antibodies in serum. There has been much debate as to whether this is due to diisocyanate-induced asthma being mediated by non-IgE mechanisms or whether it is the result of using inappropriate conjugates.

OBJECTIVE

We sought to determine whether RNA message for Cepsilon, IL-4, and other associated inflammatory markers could be detected locally within the bronchial mucosa after diisocyanate challenge.

METHODS

Fiberoptic bronchoscopic bronchial biopsy specimens were obtained at 24 hours after both a control and an active challenge in 5 patients with positive and 7 patients with negative inhalation test responses to diisocyanates. Using both immunohistochemistry and in situ hybridization, we determined mRNA for Cepsilon, IL-4, IL-5, and other associated inflammatory markers.

RESULTS

There was a striking absence of Cepsilon and IL-4 mRNA-positive cells in bronchial biopsy specimens from patients challenged with diisocyanate (Cepsilon median of 0 and interquartile range of 0-1.85; IL-4 median of 0 and interquartile range of 0-0.85). In contrast, there were increased numbers of IL-5-, CD25-, and CD4-positive cells and a trend toward an increase in eosinophils after active challenge with diisocyanate.

CONCLUSION

We found a striking absence of both bronchial Cepsilon and IL-4 RNA message after inhalation challenge with diisocyanates, irrespective of whether the challenge test response was positive or negative. We propose that diisocyanate-induced asthma is a non-IgE-mediated disease, at least in patients in whom specific IgE antibodies to diisocyanates are undetectable.

Quantitative expression levels of regulated on activation, normal T cell expressed and secreted and eotaxin transcripts in toluene diisocyanate-induced allergic rats

CONCLUSION

These results suggest that eotaxin may play a predominant role in controlling antigen-induced eosinophil recruitment into tissue. Objective To investigate the expression levels of regulated on activation, normal T cell expressed and secreted (RANTES) mRNA and eotaxin mRNA in the nasal mucosa of toluene diisocyanate (TDI)-induced allergic rats and to evaluate which of them is primarily related to selective eosinophilic infiltration by comparing their expression levels with the numbers of infiltrated eosinophils and vascular cell adhesion molecule-1 (VCAM-1).

MATERIAL AND METHODS

We quantified the expression levels of two strong eosinophilic CC chemokines (RANTES and eotaxin) and VCAM-1 at mRNA levels in the nasal mucosa of TDI-induced allergic rats using competitive polymerase chain reaction and compared their expression levels with the number of infiltrated eosinophils.

RESULTS

The number of infiltrated eosinophils was significantly increased between 3 h and Day 4 in TDI-induced allergic rats, but had decreased by Day 5. VCAM-1 mRNA expression was also increased between 3 h and Day 4. The number of infiltrated eosinophils correlated with the expression levels of VCAM-1 mRNA (p < 0.01). In contrast, expression of RANTES mRNA and eotaxin mRNA was increased between 3 h and Day 2, peaked between Days 1 and 2 and then declined. Although the expression of both chemokines correlated with the numbers of infiltrated eosinophils (p < 0.01), peak expression levels of eotaxin mRNA were 14-fold higher than baseline levels whereas RANTES mRNA expression increased 3-fold.

Effect of glucocorticoid on upregulation of histamine H1 receptor mRNA in nasal mucosa of rats sensitized by exposure to toluene diisocyanate

OBJECTIVE

Histamine is a major chemical mediator in the development of nasal allergy, which is characterized by nasal hypersensitivity. In this study, we used rats sensitized by exposure to toluene diisocyanate (TDI) as an animal model of nasal hypersensitivity and examined changes in expression of histamine H1 receptor (H1R) in the nasal mucosa. The effect of glucocorticoid on upregulation of H1R in nasal mucosa induced by TDI was also examined.

MATERIAL AND METHODS

In rats sensitized by exposure to TDI, nasal allergy-like behavior was scored during a 10-min period after TDI provocation. The expression of H1R in the nasal mucosa was determined by means of a real-time quantitative reverse transcriptase polymerase chain reaction and a [3H]mepyramine binding assay.

RESULTS

In TDI-sensitized rats, nasal allergy-like behavior, such as sneezing and watery rhinorrhea, was induced after intranasal application of TDI and nasal hypersensitivity to histamine was significantly increased. The level of H1R mRNA expression and the specific binding of [3H]mepyramine in the nasal mucosa were significantly increased after intranasal application of TDI in TDI-sensitized rats. Pretreatment with dexamethasone significantly reduced both nasal allergy-like behavior and the upregulation of H1R induced by TDI in the rats.

CONCLUSION

As shown in TDI-sensitized rats, our findings suggest that the upregulation of H1R in the nasal mucosa is one of the mechanisms responsible for nasal hypersensitivity behavior and nasal hypersensitivity to histamine and that the therapeutic effects of dexamethasone are, in part, due to its inhibitory action on the upregulation of H1R.

Inflammation-induced changes in primary afferent-evoked release of substance P within trigeminal ganglia in vivo

Substance P (SP) is synthesized in a subset of nociceptive sensory neurons and is released from their peripheral and central terminals. Here we demonstrate with the use of in vivo microdialysis and radioimmunoassay techniques that SP is also released within trigeminal ganglia following intraganglionic application of KCl, veratridine or capsaicin, and after electrical stimulation of peripheral afferent fibers. Both the basal and KCl-evoked release of SP are shown to be dependent on extracellular calcium. Using the turpentine-induced model of unilateral orofacial inflammation we also show that both the basal and KCl-evoked release of SP within trigeminal ganglia are greatly increased on the inflamed side 48 h after induction of inflammation. Coupled with previous demonstrations of excitatory effects of SP on sensory neurons, these results suggest that SP fulfils the role of a non-synaptically released diffusible chemical messenger that may modulate the somatic excitability of neurons within sensory ganglia in inflammatory pain states.

Toluene diisocyanate enhances substance P in sensory neurons innervating the nasal mucosa

Inhalation of irritants, such as toluene diisocyanate (TDI), stimulates substance P (SP) release from peripheral processes of sensory neurons innervating the airways. The purpose of this study was to determine if TDI inhalation affects intraneuronal levels of SP and preprotachykinin (PPT) messenger RNA (mRNA) in the sensory neurons of the trigeminal ganglion (TG) which innervate the nasal epithelium. The nasal cavity of Fisher-344 rats was instilled with rhodamine-labeled latex microspheres. Ten days later, the rats were exposed to 60 ppb of 2,4-2,6-TDI vapor for 2 h. The TG were removed 1, 12, 24, 48, 72, and 96 h after TDI treatment and prepared for SP immunocytochemistry and PPT in situ hybridization. SP nerve fiber density in nasal epithelium was significantly increased 12, 24, and 48 h after TDI exposure. The proportion of microsphere-labeled cell bodies expressing high levels of SP immunoreactivity was decreased at 24 h but was increased above controls at 48 and 72 h. The proportion of microsphere-labeled cell bodies expressing high levels of PPT mRNA was increased above control levels at 24 and 48 h. The percentage of leukocytes observed in nasal lavage fluid was significantly increased 12, 24, 48, and 72 h after inhalation. These studies indicate that SP production in TG neurons projecting to the nasal epithelium is transiently increased after TDI exposure, suggesting that TDI inhalation not only causes SP release but also increased intraneuronal neuropeptide levels. Increased neuronal SP levels may be involved in maintaining neurogenic inflammation or the development of airway hyperresponsiveness.

Histamine content, synthesis and degradation in nasal mucosa and lung of guinea-pigs treated with toluene diisocyanate (TDI)

We have reported the presence of a histamine synthesizing enzyme, histidine decarboxylase (HDC), and histamine degrading enzymes, histamine N-methyltransferase (HMT) and histaminase (diamine oxidase, DAO) in human nasal mucosa and the histamine content of the mucosa. In this study, we demonstrate the influences of the toluene diisocyanate (TDI) treatment on the histamine content and these enzyme activities in guinea-pigs as an animal model of respiratory hypersensitivity. Application of TDI to the nasal vestibuli induced intense nasal allergy-like and mild asthma-like responses in TDI-sensitized guinea pigs. Increases in the histamine content and HDC and HMT activities were observed in the nasal mucosa and lung of TDI-sensitized guinea pigs. No apparent changes in the histaminase activities were observed in either the nasal mucosa or the lung. These data suggest that the turnover rate of histamine is increased in the nasal mucosa and the lung of guinea pigs with respiratory hypersensitivity.

Neurogenic inflammation in nasal allergy: histochemical and pharmacological studies in guinea pigs. A review

The role of neuropeptides in nasal allergy was examined in guinea pigs by histochemical and pharmacological study. Intranasal application of toluene diisocyanate (TDI) induced nasal allergy-like behaviors: sneezing and watery rhinorrhea, and decreased histamine content in the nasal mucosa in guinea pigs sensitized with TDI. The immunoreactivity of substance P (SP) and calcitonin gene-related peptide (CGRP) in the nerve terminals in the nasal mucosa was increased after intranasal application of TDI. We also observed a decrease in the immunoreactivity of SP and CGRP, and an increase in their mRNA expression in the trigeminal ganglion neurons. These findings indicate that exposure to TDI enhanced the biosynthesis of both SP and CGRP in the trigeminal ganglion neurons and their axonal transportation to the terminals in the nasal mucosa. In animals pretreated with capsaicin before sensitization, TDI did not induce nasal allergy-like behaviors and histamine release in the nasal mucosa. Since capsaicin depletes SP and CGRP in the sensory nerves, this finding indicates neuropeptide-mediated histamine release in the nasal mucosa. All these findings suggest that, on exposure to TDI, the antidromic release of SP and CGRP in the nasal mucosa triggers the release of histamine, resulting in the development of symptoms of nasal allergy.