Up-regulation of Orai1 in murine allergic rhinitis

Stabilization of activated mast cells by ORAI1 inhibitor suppresses peanut-induced anaphylaxis and acute diarrhea

Mast cell (MC) activation triggered by immunoglobulin E (IgE)-antigen crosslinking involves intracellular Ca2+ influx through the ORAI1 channel, which precedes granule exteriorization and de novo synthesis of mediators. Pharmacologically suppressing MCs via the inhibition of the ORAI1 Ca2+ channel may represent a potential strategy for preventing anaphylaxis. This study demonstrated that peanut-induced anaphylaxis in sensitized mice resulted in significant hypothermia and acute diarrhea. Utilizing the Mcpt5cre-DTA mouse model, we demonstrated that this anaphylactic response was mediated by IgE-antigen-induced MC activation. Prophylactic administration of MC suppressors was an effective means of preventing peanut-induced anaphylaxis. In addition, we observed the potent efficacy of an ORAI1 inhibitor in suppressing the FcεRI-mediated response of murine or human MCs, even when administered concurrently or post-allergen exposure. Mechanistically, the ORAI1 inhibitor was found to prevent the association of Synaptotagmin-2 with the SNARE complex. In an in vivo mouse model of peanut-induced anaphylaxis, the administration of the ORAI1 inhibitor after allergen challenge effectively suppressed allergic acute diarrhea and ameliorated anaphylaxis. Therefore, pharmacological intervention of ORAI1 channel inhibition in MCs represents a promising therapeutic avenue for the treatment of peanut-induced anaphylaxis and acute diarrhea in vivo.

In-vitro and in-vivo anti-allergic effects of magnolol on allergic rhinitis via inhibition of ORAI1 and ANO1 channels

ETHNOPHARMACOLOGICAL RELEVANCE

Flos Magnoliae (the dried flower buds of Magnolia biondii Pamp, FM) is a known herbal traditional medicine used for the symptomatic relief of nasal congestion and rhinorrhea caused by rhinitis and sinusitis. Magnolol, a neolignan from the magnolia family, is a secondary metabolite known to have anti-allergic and anti-inflammatory effects. However, the underlying mechanisms and therapeutic effect of magnolol in the treatment of allergic rhinitis (AR) remain elusive.

AIMS OF THE STUDY

Anoctamin 1 (ANO1), a calcium-activated anion channel, mediates mucus and electrolyte secretion in nasal airway epithelial cells, whereas calcium release-activated calcium channel protein 1 (ORAI1) participates in the activation of T-lymphocytes and mast cells. The aim of our study is to understand the mechanisms of action of magnolol against AR, i.e., whether it acts through the modulation of ANO1 and ORAI1 channels that are expressed in nasal epithelial cells and T-lymphocytes, respectively.

MATERIALS AND METHODS

Whole-cell patch clamp was used to record the activity of ORAI1 and ANO1 ion channels in ORAI1 or ANO1 overexpressed HEK293T cells, while the Ussing chamber apparatus was used to measure electrolyte transport via the epithelium, in Calu-3 cells cultured in an air-liquid interface. Additionally, calcium imaging of Jurkat T-lymphocytes was used to assess changes in the intracellular calcium concentration. Magnolol toxicity was assessed using the CCK-8 assay, and its effect on T-lymphocyte proliferation was measured by labeling human primary T-lymphocytes with carboxyfluorescein succinimidyl ester. Finally, OVA-induced Balb/c mice were employed to evaluate the effect of magnolol on nasal symptoms, as well as cytokine and eosinophil infiltration in AR.

RESULTS

Magnolol inhibits ORAI1 and ANO1 channels in a concentration-dependent manner. Magnolol (30 μM) inhibits anti-CD3 induced cellular proliferation and production of IL-2 via ORAI1 channels in T-lymphocytes. Further, ATP-induced electrolyte transport mediated by ANO1 channels is significantly inhibited by magnolol in IL-4 sensitized Calu-3 cells. Notably, 300 μM magnolol significantly attenuates cytokine and eosinophil infiltration, thus alleviating AR symptoms in mice OVA-induced AR.

CONCLUSION

Magnolol may be a promising therapeutic agent for the treatment and prevention of AR.

Epithelial and sensory mechanisms of nasal hyperreactivity

"Nasal hyperreactivity" is a key feature in various phenotypes of upper airway diseases, whereby reactions of the nasal epithelium to diverse chemical and physical stimuli are exacerbated. In this review, we illustrate how nasal hyperreactivity can result from at least three types of mechanisms: (1) impaired barrier function, (2) hypersensitivity to external and endogenous stimuli, and (3) potentiation of efferent systems. We describe the known molecular basis of hyperreactivity related to the functional impairment of epithelial cells and somatosensory innervation, and indicate that the thermal, chemical, and mechanical sensors determining hyperreactivity in humans remain to be identified. We delineate research directions that may provide new insights into nasal hyperreactivity associated with rhinitis/rhinosinusitis pathophysiology and therapeutics. The elucidation of the molecular mechanisms underlying nasal hyperreactivity is essential for the treatment of rhinitis according to the precepts of precision medicine.

Intervention of Orai1 Influences the Response of Nuocytes From Allergic Rhinitis Mice to IL-33

OBJECTIVE

Nuocytes are essential in innate type-2 immunity and contribute to the exacerbation of allergic rhinitis (AR). This study aimed to evaluate the intervention of Orai1 on the response of nuocytes from AR mice to interleukin (IL)-33.

METHODS

We established a murine model of AR. Nuocytes were obtained from the mouse nasal-associated lymphoid tissue. Then, we assessed expressions of Orai1, Ca²⁺ mean fluorescence intensity (MFI) in nuocytes, and their cellular response to mouse recombinant (rm) IL-33. After that, we administered rmlentivirus vectors (lenti) that encoded small hairpin RNA (shRNA) against ORAI1 (lenti-ORAI1) into nuocytes cultures and again evaluated Orai1 and Ca²⁺ MFI in nuocytes and their response to rmIL-33. Finally, we adoptively transferred nuocytes alone or nuocytes transfected by lenti or lenti-ORAI1 to AR models to investigate their roles during allergic inflammation.

RESULTS

We showed that Orai1 and Ca²⁺ MFI were upregulated in AR mice nuocytes. These cells were induced to produce more IL-5 and IL-13 by rmIL-33. However, the intervention of Orai1 by lenti-ORAI1 in nuocytes decreased Orai1 and Ca²⁺ MFI and reduced productions of aforementioned cytokines even after the administration of rmIL-33. Numbers of sneezing, nasal rubbing, and counts of eosinophils were all enhanced after the adoptive transfer of nuocytes. Concentrations of IL-5, IL-13, and IL-33 in the nasal lavage fluid (NLF) of allergic mice were also increased. However, the adoptive transfer of nuocytes transfected by lenti-ORAI1 decreased aforementioned parameters.

CONCLUSION

These findings show that the intervention of Orai1 in nuocytes influences the response of nuocytes to rmIL-33.

Calcium release-activated calcium modulator 1 as a therapeutic target in allergic skin diseases

Allergic skin disease is the most common skin condition, and considerably affects patients' life quality because of its recurrence and pruritus. Numbers of studies point out that immune cells, including mast cells and T cells, play pathogenic roles in allergic skin diseases, and share similarities in the activation and secretion of cytokines. Calcium Release-Activated Calcium Modulator 1(CRACM1/ORAI1) is a subtype of Ca²⁺ membrane channel, causing Ca²⁺ influx into the cells. As a second messenger, Ca²⁺ is an essential element that regulates immune responses, especially in the development and function of T and B cells. Thus, ORAI1 is considered to participate in allergic diseases. However, the specific mechanism of ORAI1 in skin disorders is still unclear. In order to investigate the roles of ORAI1 in allergic skin disorders, we reviewed the related articles and concluded that ORAI1 could be a potential therapeutic target for allergic skin diseases.

A proteomics analysis reveals that A2M might be regulated by STAT3 in persistent allergic rhinitis

BACKGROUND

Proteomics tools can be used to identify the differentially expressed proteins related to allergic rhinitis (AR). However, the large numbers of proteins related to AR have not yet been explored using an advanced quantitative proteomics approach, known as isobaric tags for relative and absolute quantitation (iTRAQ).

OBJECTIVES

To identify differentially expressed proteins in persistent AR patients and to explore the regulatory signalling pathways involving the identified proteins.

METHODS

Forty-five persistent AR patients and 20 healthy controls were recruited for this study. iTRAQ was used to identify the proteins that were differentially expressed between these two groups, and a bioinformatics analysis was then conducted to identify the signalling pathways associated with the identified proteins. Immunofluorescence labelling was performed to detect alpha-2-macroglobulin (A2M), STAT3, p-STAT3 and IL17 in the nasal mucosa.

RESULTS

A total of 133 differentially expressed proteins were identified. We then determined the top 10 regulatory pathways associated with these proteins and found that the blood coagulation pathway had the most significant association. A2M, a protein involved in the blood coagulation pathway, was found to be differentially expressed in the serum of AR patients. The bioinformatics analysis indicated that STAT3 is an upstream transcription factor that might regulate A2M expression. An immunofluorescence study further confirmed that STAT3 and A2M are co-localized in nasal mucosa cells. Additionally, A2M, STAT3, p-STAT3, and IL17 are elevated in AR patients. The expressional level of A2M is positively related to IL17 and the symptom of the congestion in AR subjects.

CONCLUSIONS

The blood coagulation pathway may be a key regulatory network pathway contributing to the allergic inflammatory response in AR patients. A2M, which is regulated by STAT3, may be an important protein in the pathogenesis of allergic rhinitis in AR patients.

Expression of ORAII, a plasma membrane resident subunit of the CRAC channel, in rodent and non-rodent species

We determined the expression of ORAI1 protein in rodent and non-rodent tissues using a monoclonal antibody directed against an extracellular loop of the protein. Previous reports using antibodies directed at the C-terminus of ORAI1 have not detected central nervous system (CNS) expression. Our results demonstrate broad tissue expression that includes the CNS using a unique monoclonal antibody specific to an extracellular loop of ORAI1. In addition, we present in situ hybridization (ISH) results using a probe within the middle of the mouse coding region showing CNS expression of Orai1 RNA. We contrast the patterns of rodent and human tissue expression and conclude that rodents have similar expression of ORAI1 in most tissue types when compared to primates, with an important exception being the male reproductive system, where human-specific expression is observed.

Amelioration of Muc5b mucin hypersecretion is enhanced by IL-33 after 2-APB administration in a murine model of allergic rhinitis

We attempted to clarify whether hypersecretion of Muc5b mucin from mouse nasal submucosal glands that is enhanced by interleukin (IL)-33 under allergic conditions can be ameliorated by administration of 2-APB. Immunohistochemistry was used to examine both the distribution of T cells in the nasal mucosa of an allergic rhinitis mouse model and expressions of IL-33 receptor ST2 and Muc5b protein in mouse submucosal gland cells. The amounts of protein and mRNA of Orai1, Muc5b, IL-4, IL-5, IL-13 and IL-33 in mouse nasal lavage fluid (NLF) and nasal mucosa were determined using enzyme-linked immunosorbent assay and real-time reverse transcription-polymerase chain reaction. Expressions of Orai1, Muc5b, IL-4, IL-5, IL-13 and IL-33 were up-regulated in the allergic state and IL-33 increased the levels of Muc5b, IL-4, IL-5 and IL-13, but did not influence proliferation of T cells; however, ST2 was diminished in nasal submucosal gland cells. 2-APB reduced proliferation of T cells and the Orai1 level in the nasal mucosa. It also reduced the concentrations of IL-4, IL-5 and IL-13 in NLF and nasal mucosa, and hypersecretion of Muc5b from glandular cells that was enhanced by IL-33, but did not affect IL-33 production. 2-APB decreased Muc5b mucin hypersecretion from submucosal gland that was enhanced by IL-33 in allergic mice by limiting Ca(2+) release-activated Ca(2+) channel activity in which Orai1 plays a crucial role in the gland cells and/or by controlling channel activation in T cells and proliferation of these cells.

Emerging roles of store-operated Ca²⁺ entry through STIM and ORAI proteins in immunity, hemostasis and cancer

Store-operated Ca(2+) entry (SOCE) is an important Ca(2+) influx pathway, which is defined by the fact that depletion of intracellular Ca(2+) stores, mainly the endoplasmic reticulum (ER), triggers the opening of Ca(2+) channels in the plasma membrane. The best characterized SOC channel is the Ca(2+) release-activated Ca(2+) (CRAC) channel, which was first described in cells of the immune system but has since been reported in many different cell types. CRAC channels are multimers of ORAI family proteins, of which ORAI1 is the best characterized. They are activated by stromal interaction molecules (STIM) 1 and 2, which respond to the depletion of intracellular Ca(2+) stores with oligomerization and binding to ORAI proteins. The resulting SOCE is critical for the physiological function of many cell types including immune cells and platelets. Recent studies using cell lines, animal models and primary cells from human patients with defects in SOCE have highlighted the importance of this Ca(2+) entry mechanism in a variety of pathophysiological processes. This review focuses on the role of SOCE in immunity to infection, allergy, hemostasis and cancer.

Molecular modulation of airway epithelial ciliary response to sneezing

Our purpose was to evaluate the effect of the mechanical force of a sneeze on sinonasal cilia function and determine the molecular mechanism responsible for eliciting the ciliary response to a sneeze. A novel model was developed to deliver a stimulation simulating a sneeze (55 mmHg for 50 ms) at 26°C to the apical surface of mouse and human nasal epithelial cells. Ciliary beating was visualized, and changes in ciliary beat frequency (CBF) were determined. To interrogate the molecular cascades driving sneeze-induced changes of CBF, pharmacologic manipulation of intra- and extracellular calcium, purinergic, PKA, and nitric oxide (NO) signaling were performed. CBF rapidly increases by ≥150% in response to a sneeze, which is dependent on the release of adenosine triphosphate (ATP), calcium influx, and PKA activation. Furthermore, apical release of ATP is independent of calcium influx, but calcium influx and subsequent increase in CBF are dependent on the ATP release. Lastly, we observed a blunted ciliary response in surgical specimens derived from patients with chronic rhinosinusitis compared to control patients. Apical ATP release with subsequent calcium mobilization and PKA activation are involved in sinonasal ciliary response to sneezing, which is blunted in patients with upper-airway disease.

Downregulation of Orai1 expression in the airway alleviates murine allergic rhinitis

Orai1 is the key subunit of the Ca(2+)-release-activated Ca(2+) channel. Our previous report has demonstrated that Orai1 expression in the airway was upregulated in the ovalbumin (OVA)-induced allergic rhinitis (AR) mouse models. To observe whether inhibition of Orai1 expression in the airway could suppress symptoms in a murine model of AR and to assess the impacts of this inhibition on the responses of local and systemic immunocytes, we administered recombinant lentivirus vectors that encoded shRNA against ORAI1 (lenti-ORAI1) into the nostrils of OVA-sensitized mice before the challenges, and analyzed its effect on allergic responses, as compared with the unsensitized mice and untreated AR mice. Administration of lenti-ORAI1 into the nasal cavity successfully infected cells in the epithelial layer of the nasal mucosa, and significantly decreased the frequencies of sneezing and nasal rubbing of the mice. Protein levels of leukotriene C4, OVA-specific IgE, and IL-4 in the nasal lavage fluid and serum and eosinophil cation protein in the serum were also significantly reduced by lenti-ORAI1, as were the mRNA levels of these factors in the nasal mucosa and spleen. These data suggested that administration of lenti-ORAI1 into the nasal cavity effectively decreased Orai1 expression in the nasal mucosa, alleviated AR symptoms, and partially inhibited the hyperresponsiveness of the local and systemic immune cells including T cells, B cells, mast cells and eosinophils that are involved in the pathogenesis of AR.

Influence of Orai1 intervention on mouse airway epithelium reactions in vivo and in vitro

BACKGROUND

Orai1 is crucial for store-operated Ca2(+) entry and Ca2(+) release-activated Ca2(+) channel activities. However, little is known about its function in allergic diseases.

OBJECTIVE

To assess the influence of Orai1 intervention on mouse airway epithelium reactions in vivo and in vitro.

METHODS

We used immunohistochemical staining, enzyme-linked immunosorbent assay, and real-time reverse transcription-polymerase chain reaction to evaluate Orai1 expression in nasal and tracheal mucosa epithelium of nonsensitized, control, and 2-aminoethoxydiphenyl borate (2-APB)-treated groups in vivo and in vitro. In addition, we analyzed concentrations of interleukin 1β, interleukin 6, macrophage inflammatory protein 2, and tumor necrosis factor α in nasal lavage fluid, bronchoalveolar lavage fluid, and culture supernatant and their messenger RNAs in nasal and tracheal mucosa and cultured nasal and tracheal epithelium.

RESULTS

Administration of 2-APB into the nostrils suppressed Orai1 expression in nasal and tracheal mucosa of treated mice compared with that in control mice and restrained the mediators in nasal lavage fluid, bronchoalveolar lavage fluid, and airway mucosa of treated groups compared with those in control groups. Similarly, the 2-APB intervention also alleviated Orai1 and the production of the mediators in culture supernatant and cultured airway epithelium under allergic conditions.

CONCLUSIONS

Our results indicate that 2-APB could effectively ameliorate reactions of upper and lower airway epithelial cells in mice in allergic states in vivo and in vitro.

Histochemistry and cell biology: the annual review 2010

This review summarizes recent advances in histochemistry and cell biology which complement and extend our knowledge regarding various aspects of protein functions, cell and tissue biology, employing appropriate in vivo model systems in conjunction with established and novel approaches. In this context several non-expected results and discoveries were obtained which paved the way of research into new directions. Once the reader embarks on reading this review, it quickly becomes quite obvious that the studies contribute not only to a better understanding of fundamental biological processes but also provide use-oriented aspects that can be derived therefrom.