Downregulation of Orai1 expression in the airway alleviates murine allergic rhinitis

HDAC3-mediated lncRNA ZFAS1 inhibited IL-13-induced secretion of proinflammatory cytokines in nasal epithelial cells by regulating the miR-7-5p/SIRT1 pathway

Allergic rhinitis (AR) is a disease that is difficult to cure and accompanies the patient's life. Proinflammatory cytokines (GM-CSF and eotaxin) and MUC5AC are key mediators promoting AR progression. Herein, the function of lncRNA ZFAS1 in AR was investigated. Nasal epithelial cells (NECs) were subjected to 50 ng/mL IL-13 for 24 h to construct an AR cell model. The mRNA and protein expressions were assessed using qRT-PCR and western blot. The levels of GM-CSF, eotaxin, IL-1β, IL-6, TNF-α and MUC5AC in cell supernatant were examined by ELISA. The binding relationships between HDAC3, ZFAS1, miR-7-5p and SIRT1 were analysed using dual luciferase reporter or ChIP assays. Herein, our results displayed that ZFAS1 and SIRT1 were lowly expressed in AR, while miR-7-5p and HDAC3 were highly expressed. Functional experiments displayed that ZFAS1 overexpression suppressed IL-13-induced proinflammatory cytokines and mucin production in NECs. The highly expressed HDAC3 in AR inhibited ZFAS1 expression by binding with ZFAS1 promoter. In addition, our experiments revealed that ZFAS1 targeted miR-7-5p, and miR-7-5p targeted SIRT1. As expected, miR-7-5p overexpression or SIRT1 silencing abrogated ZFAS1 upregulation's repression on IL-13-induced proinflammatory cytokines and MUC5AC secretory levels in NECs. ZFAS1 suppressed proinflammatory cytokines, inflammatory cytokines, and MUC5AC secretory levels in AR by regulating the miR-7-5p/SIRT1 axis. Thus, our work suggested that ZFAS1 might serve as a novel target for AR treatment and prevention.

MIR222HG attenuates macrophage M2 polarization and allergic inflammation in allergic rhinitis by targeting the miR146a-5p/TRAF6/NF-κB axis

Although M2 macrophages are involved in the orchestration of type 2 inflammation in allergic diseases, the mechanisms underlying non-coding RNA (ncRNA)-mediated macrophage polarization in allergic rhinitis (AR) have not been systematically understood. Here, we identified long non-coding RNA (lncRNA) MIR222HG as a key regulator of macrophage polarization and revealed its role in AR. Consistent with our bioinformatic analysis of GSE165934 dataset derived from the Gene Expression Omnibus (GEO) database, lncRNA-MIR222HG and murine mir222hg were downregulated in our clinical samples and animal models of AR, respectively. Mir222hg was upregulated in M1 macrophages and downregulated in M2 macrophages. The allergen-ovalbumin facilitated polarization of RAW264.7 cells to the M2 phenotype, accompanied by the downregulation of mir222hg expression in a dose-dependent manner. Mir222hg facilitates macrophage M1 polarization and reverses M2 polarization caused by ovalbumin. Furthermore, mir222hg attenuates macrophage M2 polarization and allergic inflammation in the AR mouse model. Mechanistically, a series of gain- and loss-of-function experiments and rescue experiments were performed to verify the role of mir222hg as a ceRNA sponge that adsorbed miR146a-5p, upregulated Traf6, and activated the IKK/IκB/P65 pathway. Collectively, the data highlight the remarkable role of MIR222HG in the modulation of macrophage polarization and allergic inflammation, as well as its potential role as a novel AR biomarker or therapeutic target.

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.

MicroRNA-182-5p relieves murine allergic rhinitis via TLR4/NF-κB pathway

Allergic rhinitis (AR) is one of the most common chronic diseases. This study examined whether microRNA (miR)-182-5p plays a role in AR by regulating toll-like receptor 4 (TLR4). First, data demonstrated that TLR4 was a target of miR-182-5p. Subsequently, AR mouse model was established to explore the role of miR-182-5p and TLR4 in AR in vivo. Initially, quantitative reverse transcription-PCR (qRT-PCR) analysis indicated that miR-182-5p was downregulated, while TLR4 expression was upregulated in AR mice. Then we found that miR-182-5p mimic reduced the frequency of sneezing and nose rubbing of the AR mice. In addition, miR-182-5p mimic significantly increased ovalbumin (OVA)-specific IgE and leukotriene C4 expression levels in nasal lavage fluid (NLF) and serum of AR mice. miR-182-5p mimic decreased the number of inflammatory cells in NLF of AR mice. It also reduced the levels of inflammatory factors in the serum of AR mice, such as interleukin (IL)-4, IL-5, IL-13, IL-17 and tumor necrosis factor (TNF)-α, while increasing the release of IFN-γ and IL-2. Finally, miR-182-5p mimic inhibited NF-κB signaling pathway activation in AR mice. However, all effects of miR-182-5p mimic on AR mice were reversed by TLR4-plasmid. In conclusion, miR-182-5p/TLR4 axis may represent a novel therapeutic target for AR.

Silencing of CD86 in dendritic cells by small interfering RNA regulates cytokine production in T cells from patients with allergic rhinitis in vitro

The aim of the present study was to investigate the expression and role of the co‑stimulatory molecule T‑lymphocyte activation antigen CD86 (CD86) in dendritic cells (DCs) from the peripheral blood of patients with allergic rhinitis (AR) compared with those from healthy individuals. It was observed that mature DCs from the peripheral blood of patients with AR expressed high levels of the co‑stimulatory molecule CD86, but not CD80, compared with healthy control subjects. CD86 expression levels in DCs decreased significantly following transfection with siRNA in a lentiviral vector. Furthermore, the level of transforming growth factor‑β1 produced by T cells co‑cultured with DCs was significantly increased in the siRNA group, while interleukin (IL)‑4 and IL‑5 production was significantly decreased. The findings of the present study indicated that CD86 may play a pivotal role in the regulatory T cell/type 2 helper T cell imbalance in allergic inflammation.

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.

Inhibition of TLR4 inhibits allergic responses in murine allergic rhinitis by regulating the NF-κB pathway

The present study investigated the underlying mechanisms and effects of toll-like receptor 4 (TLR4) on a mouse model of allergic rhinitis (AR). An ovalbumin (OVA)-induced mouse model of AR was treated with TLR4-short hairpin RNA (shRNA). Allergic symptoms were then subsequently assessed. Protein levels of OVA-specific immunoglobulin E (IgE), eosinophil cation protein (ECP), leukotriene C4 (LTC4) and prostaglandin D2 (PGD2) in mice serum and nasal lavage fluid, as well as various inflammatory cytokine mediators in mice serum, were determined by ELISA. Protein level detection was performed using reverse transcription-quantitative PCR and western blot analysis. The results revealed that TLR4 was highly expressed in the nasal mucosa of AR mice. TLR4 inhibition significantly relieved OVA-induced AR symptoms. Relief of symptoms was evidenced by a decreased frequency of sneezing and nose friction, reduced levels of OVA-specific IgE, ECP, LTC4, PGD2, less inflammatory cells and decreased levels of T-helper 2 type cytokines. In addition, the data indicated that OVA-induced activation of the NF-κB pathway was repressed by TLR4-shRNA. The results of the current study indicate that TLR4 may be a promising therapeutic target of AR.

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.

Integrins are Mechanosensors That Modulate Human Eosinophil Activation

Eosinophil migration to the lung is primarily regulated by the eosinophil-selective family of eotaxin chemokines, which mobilize intracellular calcium (Ca²⁺) and orchestrate myriad changes in cell structure and function. Eosinophil function is also known to be flow-dependent, although the molecular cognate of this mechanical response has yet to be adequately characterized. Using confocal fluorescence microscopy, we determined the effects of fluid shear stress on intracellular calcium concentration ([Ca²⁺]_i) in human peripheral blood eosinophils by perfusing cells in a parallel-plate flow chamber. Our results indicate that fluid perfusion evokes a calcium response that leads to cell flattening, increase in cell area, shape change, and non-directional migration. None of these changes are seen in the absence of a flow stimulus, and all are blocked by chelation of intracellular Ca²⁺ using BAPTA. These changes are enhanced by stimulating the cells with eotaxin-1. The perfusion-induced calcium response (PICR) could be blocked by pre-treating cells with selective (CDP-323) and non-selective (RGD tripeptides) integrin receptor antagonists, suggesting that α₄β₇/α₄β₁ integrins mediate this response. Overall, our study provides the first pharmacological description of a molecular mechanosensor that may collaborate with the eotaxin-1 signaling program in order to control human eosinophil activation.

Lentiviral shRNA against KCa3.1 inhibits allergic response in allergic rhinitis and suppresses mast cell activity via PI3K/AKT signaling pathway

Calcium-activated potassium ion channel-3.1 (KCa3.1) plays a pivotal role in the potassium-calcium exchange involved in atopy. This study aimed to explore the impact of lentiviral-mediated shRNA silencing KCa3.1 on allergic response in a murine allergic rhinitis (AR) model. The BALB/c mice were divided into four groups: untreated AR group, negative control AR group, lentiviral KCa3.1-shRNA treated AR group and normal control group. Concentrations of ovalbumin (OVA)-specific IgE, histamine and leukotrienes C4 (LTC4) in serum, and IL-4, IL-9 and IL-17 in nasal lavage fluid (NLF) were analyzed. Goblet cells and mast cells were counted. KCa3.1 positive cells were counted after immunolabelling by immunofluorescence method. KCa3.1, Mucin 5AC (MUC5AC), and tryptase mRNA levels were determined using real-time polymerase chain reaction. Furthermore, P815 cell line was used to explore the role and mechanism of lentiviral KCa3.1-shRNA on mast cells. The results showed that LV-KCa3.1-shRNA intervention effectively attenuated allergic responses in LV-KCa3.1-shRNA treated mice. LV-KCa3.1-shRNA intervention effectively suppressed KCa3.1 levels and phosphorylation of AKT in P815 cells, leading to the downregulation of tryptase, IL-6 and IL-8 levels. LV-KCa3.1-shRNA intervention effectively attenuated the allergic responses in AR and suppressed mast cell activity by inhibiting PI3K/AKT signaling pathway.

Ca2+ -activated K+ channel-3.1 blocker TRAM-34 alleviates murine allergic rhinitis

The precise pathogenesis of allergic rhinitis (AR) remains unclear and AR is less easily cured. Recent evidence has suggested that calcium-activated K+ channel-3.1(KCa3.1) is implicated in the immune response of allergic and inflammatory diseases and TRAM-34 is a selective KCa3.1 blocker. However, little is known about its role in AR. We aimed to investigate the effect of TRAM-34 in a mouse model of AR induced by ovalbumin (OVA). The BALB/c mice were divided into six groups: untreated AR group, 200 μg TRAM-34 treated AR group, 400 μg TRAM-34 treated AR group, 200 μg TRAM-34 treated normal group, 400 μg TRAM-34 treated normal group and untreated normal control group. Histopathological characteristics were assessed by HE staining. KCa3.1 protein expression was investigated by immunohistochemistry and western blotting method, and mRNA expression of KCa3.1, stromal interaction molecule1 (STIM1) and Orai1 in nasal tissues were assessed by real-time PCR. Furthermore, concentrations of OVA-specific IgE, ECP, IL-4, IL-5, IL-17 and IL-1β in nasal lavage fluid (NLF) were analyzed by enzyme-linked immunosorbent assay (ELISA). Results showed that TRAM-34 administration into the nostril attenuated sneezing, nasal rubbing, epithelial cell proliferation, eosinophil infiltration and inhibited nasal mucosa KCa3.1, STIM1 and Orai1 expression in TRAM-34 treated mice compared with untreated AR mice and suppressed inflammatory cytokines in the NLF of TRAM-34 treated groups compared with untreated AR mice. In conclusion, TRAM-34 could effectively alleviate murine allergic rhinitis by suppressing KCa3.1 and leads to reduction of K+ efflux and Ca2 + influx, leading to inflammation reduction and allergic responses attenuation.

Accelerating cancer modeling with RNAi and nongermline genetically engineered mouse models

For more than two decades, genetically engineered mouse models have been key to our mechanistic understanding of tumorigenesis and cancer progression. Recently, the massive quantity of data emerging from cancer genomics studies has demanded a corresponding increase in the efficiency and throughput of in vivo models for functional testing of putative cancer genes. Already a mainstay of cancer research, recent innovations in RNA interference (RNAi) technology have extended its utility for studying gene function and genetic interactions, enabling tissue-specific, inducible and reversible gene silencing in vivo. Concurrent advances in embryonic stem cell (ESC) culture and genome engineering have accelerated several steps of genetically engineered mouse model production and have facilitated the incorporation of RNAi technology into these models. Here, we review the current state of these technologies and examine how their integration has the potential to dramatically enhance the throughput and capabilities of animal models for cancer.

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.

STIM proteins: dynamic calcium signal transducers

Stromal interaction molecule (STIM) proteins function in cells as dynamic coordinators of cellular calcium (Ca(2+)) signals. Spanning the endoplasmic reticulum (ER) membrane, they sense tiny changes in the levels of Ca(2+) stored within the ER lumen. As ER Ca(2+) is released to generate primary Ca(2+) signals, STIM proteins undergo an intricate activation reaction and rapidly translocate into junctions formed between the ER and the plasma membrane. There, STIM proteins tether and activate the highly Ca(2+)-selective Orai channels to mediate finely controlled Ca(2+) signals and to homeostatically balance cellular Ca(2+). Details are emerging on the remarkable organization within these STIM-induced junctional microdomains and the identification of new regulators and alternative target proteins for STIM.