Anti-ORAI1 antibody DS-2741a, a specific CRAC channel blocker, shows ideal therapeutic profiles for allergic disease via suppression of aberrant T-cell and mast cell activation

Therapeutic monoclonal antibodies in allergy: Targeting IgE, cytokine, and alarmin pathways

The etiology of allergy is closely linked to type 2 inflammatory responses ultimately leading to the production of allergen-specific immunoglobulin E (IgE), a key driver of many allergic conditions. At a high level, initial allergen exposure disrupts epithelial integrity, triggering local inflammation via alarmins including IL-25, IL-33, and TSLP, which activate type 2 innate lymphoid cells as well as other immune cells to secrete type 2 cytokines IL-4, IL-5 and IL-13, promoting Th2 cell development and eosinophil recruitment. Th2 cell dependent B cell activation promotes the production of allergen-specific IgE, which stably binds to basophils and mast cells. Rapid degranulation of these cells upon allergen re-exposure leads to allergic symptoms. Recent advances in our understanding of the molecular and cellular mechanisms underlying allergic pathophysiology have significantly shaped the development of therapeutic intervention strategies. In this review, we highlight key therapeutic targets within the allergic cascade with a particular focus on past, current and future treatment approaches using monoclonal antibodies. Specific targeting of alarmins, type 2 cytokines and IgE has shown varying degrees of clinical benefit in different allergic indications including asthma, chronic spontaneous urticaria, atopic dermatitis, chronic rhinosinusitis with nasal polyps, food allergies and eosinophilic esophagitis. While multiple therapeutic antibodies have been approved for clinical use, scientists are still working on ways to improve on current treatment approaches. Here, we provide context to understand therapeutic targeting strategies and their limitations, discussing both knowledge gaps and promising future directions to enhancing clinical efficacy in allergic disease management.

Agrimonia coreana Extract Exerts Its Therapeutic Effect through CRAC Channel Inhibition for Atopic Dermatitis Treatment

Atopic dermatitis (AD) is a common allergic inflammatory skin condition marked by severe itching, skin lichenification, and chronic inflammation. AD results from a complex immune response, primarily driven by T lymphocytes and environmental triggers, leading to a disrupted epidermal barrier function. Traditional treatments, such as topical corticosteroids, have limitations due to long-term side effects, highlighting the need for safer alternatives. Here, we aimed to show that Agrimonia coreana extract (ACext) can be used in treating AD-related dermatologic symptoms. ACext could inhibit CRAC (Calcium Release-Activated Calcium) channel activity, reducing Orai1/CRAC currents and decreasing intracellular calcium signaling. This inhibition was further confirmed by the reduced IL-2 levels and T cell proliferation upon ACext treatment. In a mouse model of AD, ACext significantly ameliorates symptoms, improves histological parameters, and enhances skin barrier function, demonstrating its potential for treating AD.

Regulation of T Lymphocyte Functions through Calcium Signaling Modulation by Nootkatone

Recent advancements in understanding the intricate molecular mechanisms underlying immunological responses have underscored the critical involvement of ion channels in regulating calcium influx, particularly in inflammation. Nootkatone, a natural sesquiterpenoid found in Alpinia oxyphylla and various citrus species, has gained attention for its diverse pharmacological properties, including anti-inflammatory effects. This study aimed to elucidate the potential of nootkatone in modulating ion channels associated with calcium signaling, particularly CRAC, KV1.3, and KCa3.1 channels, which play pivotal roles in immune cell activation and proliferation. Using electrophysiological techniques, we demonstrated the inhibitory effects of nootkatone on CRAC, KV1.3, and KCa3.1 channels in HEK293T cells overexpressing respective channel proteins. Nootkatone exhibited dose-dependent inhibition of channel currents, with IC50 values determined for each channel. Nootkatone treatment did not significantly affect cell viability, indicating its potential safety for therapeutic applications. Furthermore, we observed that nootkatone treatment attenuated calcium influx through activated CRAC channels and showed anti-proliferative effects, suggesting its role in regulating inflammatory T cell activation. These findings highlight the potential of nootkatone as a natural compound for modulating calcium signaling pathways by targeting related key ion channels and it holds promise as a novel therapeutic agent for inflammatory disorders.

Orai1 Ca2+ channel modulators as therapeutic tools for treating cancer: Emerging evidence!

In non-excitable cells, Orai proteins represent the main channel for Store-Operated Calcium Entry (SOCE), and also mediate various store-independent Calcium Entry (SICE) pathways. Deregulation of these pathways contribute to increased tumor cell proliferation, migration, metastasis, and angiogenesis. Among Orais, Orai1 is an attractive therapeutic target explaining the development of specific modulators. Therapeutic trials using Orai1 channel inhibitors have been evaluated for treating diverse diseases such as psoriasis and acute pancreatitis, and emerging data suggest that Orai1 channel modulators may be beneficial for cancer treatment. This review discusses herein the importance of Orai1 channel modulators as potential therapeutic tools and the added value of these modulators for treating cancer.

House dust mite allergens, store-operated Ca2+ channels and asthma

The house dust mite is the principal source of aero-allergen worldwide. Exposure to mite-derived allergens is associated with the development of asthma in susceptible individuals, and the majority of asthmatics are allergic to the mite. Mite-derived allergens are functionally diverse and activate multiple cell types within the lung that result in chronic inflammation. Allergens activate store-operated Ca2+ release-activated Ca2+ (CRAC) channels, which are widely expressed in multiple cell types within the lung that are associated with the pathogenesis of asthma. Opening of CRAC channels stimulates Ca2+ -dependent transcription factors, including nuclear factor of activated T cells and nuclear factor-κB, which drive expression of a plethora of pro-inflammatory cytokines and chemokines that help to sustain chronic inflammation. Here, I describe drivers of asthma, properties of mite-derived allergens, how the allergens are recognized by cells, the signalling pathways used by the receptors and how these are transduced into functional effects, with a focus on CRAC channels. In vivo experiments that demonstrate the effectiveness of targeting CRAC channels as a potential new therapy for treating mite-induced asthma are also discussed, in tandem with other possible approaches.

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.

Super resolution microscopy analysis reveals increased Orai1 activity in asthma and cystic fibrosis lungs

QUESTION

In diseases such as asthma and cystic fibrosis (CF), the immune response is dysregulated and the lung is chronically inflamed. Orai1 activation is required for the initiation and persistence of inflammation. However, Orai1 expression in the lung is poorly understood. We therefore tested the hypothesis that Orai1 expression was upregulated in asthmatic and CF lungs.

MATERIALS AND METHODS

We used LungMAP to analyze single-cell RNAseq data of Orai1 and stromal interaction molecule 1 (STIM1) expression in normal human lungs. We then performed RNAscope analysis and immunostaining on lung sections from normal, asthma, and CF donors. We imaged sections by confocal and super resolution microscopy, and analyzed Orai1 and STIM1 expression in different pulmonary cell types.

RESULTS

Orai1 was broadly-expressed, but expression was greatest in immune cells. At mRNA and protein levels, there were no consistent trends in expression levels between the three phenotypes. Orai1 must interact with STIM1 in order to activate and conduct Ca2+. We therefore used STIM1/Orai1 co-localization as a marker of Orai1 activity. Using this approach, we found significantly increased co-localization between these proteins in epithelia, interstitial and luminal immune cells, but not alveoli, from asthma and CF lungs. Orai1 also aggregates as part of its activation process. Using super resolution microscopy, we also found significantly increased Orai1 aggregation in immune cells from asthmatic and CF lungs.

CONCLUSION

We found evidence that Orai1 was more active in asthma and CF than normal lungs. These data suggest that Orai1 is a relevant target for reducing pulmonary inflammation.

PLC-IP3-ORAI pathway participates in the activation of the MRGPRB2 receptor in mouse peritoneal mast cells

A novel mast cell-specific G-protein-coupled receptor (GPCR), known as Mas-related G protein-coupled receptor-B2 (MRGPRB2), plays important roles in immune response. However, the opening of ion channels mediated by MRGPRB2 activation remains unclear. In this study, we found that [Ca²⁺]i elevation and voltage-dependent current generated by MRGPRB2 activation were correlated with extracellular calcium concentration. The increases in [Ca²⁺]i and voltage-dependent current caused by MRGPRB2 activation were blocked by U73122 (PLC blocker) or 2-APB (IP3 blocker) or synta66 (ORAI blocker). The voltage-dependent current induced by MRGPRB2 was inhibited by calcium-activated chlorine channel (CACCS) blockers, DIDS, or NPPB. Our results indicated the involvement of the PLC-IP3-ORAI signaling pathway and CACCS in MRGPRB2-mediated mast cell activation.

Pharmacological blockade of KV1.3 channel as a promising treatment in autoimmune diseases

There are more than 100 autoimmune diseases (AD), which have a high prevalence that ranges between 5% and 8% of the general population. Type I diabetes mellitus, multiple sclerosis, systemic lupus erythematosus and rheumatoid arthritis remain the health problem of highest concern among people worldwide due to its high morbidity and mortality. The development of new treatment strategies has become a research hotspot. In recent years, the study of the ion channels presents in the cells of the immune system, regarding their functional role, the consequences of mutations in their genes and the different ways of blocking them are the subject of intense research. Pharmacological blockade of KV1.3 channel inhibits Ca2+ signaling, T cell proliferation, and pro-inflammatory interleukins production in human CD4⁺ effector memory T cells. These cells mediated most of the AD and their inhibition is a promising therapeutic target. In this review, we will highlight the biological function of KV1.3 channel in T cells, consequence of the pharmacological inhibition (through anemone and scorpion toxins, synthetic peptides, nanoparticles, or monoclonal antibodies) as well as the possible therapeutical application in AD.

Targeted Therapies in Autoimmune Skin Diseases

Unlike the established anti-inflammatory drugs with a broad range, new-targeted therapeutic approaches have emerged in the management of autoimmune skin diseases to increase efficacy and decrease adverse reactions on the basis of an improved molecular understanding of pathogenesis. Most inflammatory dermatoses are driven by misled immune responses physiologically directed at exogenous pathogens, that is, type 1 immunity against viral pathogens, type 2 immunity against parasites, and type 3 immunity against fungi and bacteria. Pathogenic hallmarks of these major immune reaction patterns are characterized within this article, and a comprehensive overview of current clinical trials evaluating targeted therapeutics for respective dermatoses is outlined.

Store-operated Ca2+ entry as a key oncogenic Ca2+ signaling driving tumor invasion-metastasis cascade and its translational potential

Tumor metastasis is the primary cause of treatment failure and cancer-related deaths. Store-operated Ca²⁺ entry (SOCE), which is mediated by stromal interaction molecules (STIM) and ORAI proteins, has been implicated in the tumor invasion-metastasis cascade. Epithelial-mesenchymal transition (EMT) is a cellular program that enables tumor cells to acquire the capacities needed for migration and invasion and the formation of distal metastases. Tumor-associated angiogenesis contributes to metastasis because aberrantly developed vessels offer a path for tumor cell dissemination as well as supply sufficient nutrients for the metastatic colony to develop into metastasis. Recently, increasing evidence has indicated that SOCE alterations actively participate in the multi-step process of tumor metastasis. In addition, the dysregulated expression of STIM/ORAI has been reported to be a predictor of poor prognosis. Herein, we review the latest advances about the critical role of SOCE in the tumor metastasis cascade and the underlying regulatory mechanisms. We emphasize the contributions of SOCE to the EMT program, tumor cell migration and invasion, and angiogenesis. We further discuss the possibility of modulating SOCE or intervening in the downstream signaling pathways as a feasible targeting therapy for cancer treatment.

Flos magnoliae constituent fargesin has an anti-allergic effect via ORAI1 channel inhibition

Flos magnoliae (FM), the dry flower buds of Magnolia officinalis or its related species, is a traditional herbal medicine commonly used in Asia for symptomatic relief of and treating allergic rhinitis, headache, and sinusitis. Although several studies have reported the effects of FM on store-operated calcium entry (SOCE) via the ORAI1 channel, which is essential during intracellular calcium signaling cascade generation for T cell activation and mast cell degranulation, the effects of its isolated constituents on SOCE remain unidentified. Therefore, we investigated which of the five major constituents of 30% ethanoic FM (vanillic acid, tiliroside, eudesmin, magnolin, and fargesin) inhibit SOCE and their physiological effects on immune cells. The conventional whole-cell patch clamp results showed that fargesin, magnolin, and eudesmin significantly inhibited SOCE and thus human primary CD4⁺ T lymphocyte proliferation, as well as allergen-induced histamine release in mast cells. Among them, fargesin demonstrated the most potent inhibitory effects not only on ORAI1 (IC50 = 12.46 ± 1.300 μM) but also on T-cell proliferation (by 87.74% ± 1.835%) and mast cell degranulation (by 20.11% ± 5.366%) at 100 μM. Our findings suggest that fargesin can be a promising candidate for the development of therapeutic drugs to treat allergic diseases.

Mini-review: antibody therapeutics targeting G protein-coupled receptors and ion channels

Antibodies are now well established as therapeutics with many additional advantages over small molecules and peptides relative to their selectivity, bioavailability, half-life and effector function. Major classes of membrane-associated protein targets include G protein-coupled receptors (GPCRs) and ion channels that are linked to a wide range of disease indications across all therapeutic areas. This mini-review summarizes the antibody target landscape for both GPCRs and ion channels as well as current progress in the respective research and development pipelines with some example case studies highlighted from clinical studies, including those being evaluated for the treatment of symptoms in COVID-19 infection.