Thymic Stromal Lymphopoietin Research Articles

Critical and diverse role of alarmin cytokines in parasitic infections

Alarmin cytokines including IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) function as danger signals to trigger host immunity in response to tissue injury caused by pathogenic factors such as parasitic infections. Parasitic diseases also provide an excellent context to study their functions and mechanisms. Numerous studies have indicated that alarmin cytokine released by non-immune cells such as epithelial and stromal cells induce the hosts to initiate a type 2 immunity that drives parasite expulsion but also host pathology such as tissue injury and fibrosis. By contrast, alarmin cytokines especially IL-33 derived from immune cells such as dendritic cells may elicit an immuno-suppressive milieu that promotes host tolerance to parasites. Additionally, the role of alarmin cytokines in parasite infections is reported to depend on species of parasites, cellular source of alarmin cytokines, and immune microenvironment, all of which is relevant to the parasitic sites or organs. This narrative review aims to provide information on the crucial and diverse role of alarmin cytokines in parasitic infections involved in different organs including intestine, lung, liver and brain.

Regulatory Effects of Ishige okamurae extract and Diphlorethohydroxycarmalol on Skin Barrier Function

Ethnopharmacological relevanceThe pharmacological potential of marine organisms remains largely unexplored. Ishige Okamurae, commonly known as Pae, is extensively distributed over Asia. Its antioxidant, antibacterial, antiobesity, and anti-inflammatory properties are also being investigated. Aim of the studyIn most cases of atopic dermatitis, the stratum corneum, the outermost layer of the epidermis, is damaged, causing symptoms such as dryness and hyperproliferation of the epidermis. In particular, the disruption of cell junctions leads to damage of the skin barrier, exacerbating the disease and becoming a target for therapeutic development. Our study aims to investigate of Ishige okamurae extract (IOE) and a major compound derived from it, called Diphlorethohydroxycarmalol (DPHC), can help strengthen the skin barrier in animals with atopic dermatitis induced by 2,4-dinitrochlorobenzene (DNCB). Materials and methodsIn keratinocyte cell lines, HaCaT cells, the cytotoxicity of IOE and DPHC was assessed by MTT analysis. The gene expression of skin barrier factors and tight junctions were determined by real-time PCR in tumor necrosis factor-α/interferon-γ-stimulated HaCaT cells. In addition, JAK/STAT signaling pathway was performed to evaluating the mechanism of drugs by Western blot. Next, we studied the effects of IOE and DPHC on the skin of animals with DNCB-induced atopic dermatitis. We measured the expression of genes related of the skin barrier and tight junctions in their ear tissue. ResultsAs a result, IOE and DPHC confirmed that the expression of skin barrier proteins (thymic stromal lymphopoietin, filaggrin, loricrin, and involucrin) was improved in the DNCB-induced atopic dermatitis model and HaCaT cells. In addition, the expression of tight junction-related proteins (claudin, occludin, and tight junction protein-1) were improved. ConclusionIOE and DPHC ameliorated the atopic dermatitis lesions through alleviating the pro-inflammatory responses and tight junction protein destruction. Our results suggest that IOE and DPHC could be promising candidates for enhancing skin barrier function.

The role of epithelial alarmins and Th2 cytokines in the inflammatory response in allergic rhinitis

Allergic rhinitis (AR) occupies a leading position among the causes of morbidity throughout the world, to date, it has been diagnosed in 400 million people. In the formation and progression of AR, a significant role is assigned to cytokines associated with the second type of immune response, in particular, IL-4, IL-5, IL-9, IL-13, IL-25, IL-33, thymic stromal lymphopoietin (TSLP). This literature review provides information on the influence of the listed mediators on the structural cells of the nasal cavity and blood immune cells (T- and B-lymphocytes, eosinophils, macrophages, dendritic cells), and discusses their association with the manifestation of AR symptoms and the severity of the disease. The results of studies aimed at establishing the level of IL-4, IL-5, IL-9, IL-13, IL-25, IL-33 and TSLP in biological fluids (blood serum, nasal lavage) and their expression in nasal epithelial cells in patients with AR compared to healthy people are assessed.

Co-Stimulation with TWEAK and TGF-β1 Induces Steroid-Insensitive TSLP and CCL5 Production in BEAS-2B Human Bronchial Epithelial Cells

Steroid-resistant asthma is a common cause of refractory asthma. Type 2 inflammation is the main inflammatory response in asthma, and the mechanism underlying the steroid-resistance of type 2 inflammation has not been completely elucidated. Tumor-necrosis-factor-like apoptosis-inducing factor (TWEAK) and transforming growth factor (TGF)-β1 are involved in epithelial–mesenchymal transition (EMT) and the production of thymic stromal lymphopoietin (TSLP) and C-C motif chemokine ligand 5 (CCL5). We herein hypothesize that the combined exposure to TWEAK and TGF-β1 may result in the development of steroid resistance in bronchial epithelial cells. The bronchial epithelial cell line BEAS-2B was cultured with or without TGF-β1 or TWEAK, in the presence or absence of dexamethasone (DEX). The roles of Smad-independent pathways and MAP kinase phosphatase 1 (MKP-1) were also explored. Co-stimulation of TWEAK and TGF-β1 induced E-cadherin reduction, N-cadherin upregulation, and TSLP and CCL5 production, which were not suppressed by DEX. Inhibition of the nuclear factor kappa beta (NF-κB) and mitogen-activated protein kinase pathways downregulated steroid-unresponsive TSLP and CCL5 production, whereas knockdown of MKP-1 improved steroid-unresponsive TSLP production, induced by co-stimulation with TWEAK and TGF-β1. Therefore, co-stimulation with TWEAK and TGF-β1 can induce the steroid-insensitive production of TSLP and CCL5 in the bronchial epithelium and may contribute to airway inflammation.

Elevated circulating group-2 innate lymphoid cells expressing activation markers and correlated tryptase AB1 levels in active ascariasis

IntroductionAscaris lumbricoides infection is one of the most common soil-transmitted helminthiasis and IgE response to this helminth may increase the risk of asthma, bronchial hyperreactivity and atopy. There is not enough evidence showing the role of group-2 innate lymphoid cells (ILC2) in the pathogenesis of helminth infections in humans. Here, we aimed to investigate and characterize the influence of Ascaris lumbricoides infection on circulating ILCs in endemically exposed subjects.MethodsNon-infected (NI; n=16) and Ascaris-infected (AI; n=16) subjects from an endemic area were included. Two consecutive stool samples from each subject were examined by Kato-Katz to define parasite infection. Antibodies to the ABA-1 antigen of Ascaris and Ascaris extract were measured by ELISA. ILC subsets and their activation markers (CD25, CD69, thymic stromal lymphopoietin receptor (TSLPR) were evaluated in its PBMC by flow cytometry. Proximity extension assay (PEA) was performed to explore plasma proteins associated to infection.ResultsNo significant differences in the relative or absolute frequencies of total ILCs, ILC1, ILC2 and ILC3 cells were observed regarding the infection status. However, within AI group, IgE-sensitized subjects to ABA-1 had higher frequencies and counts of ILC2 (p<0.05). Frequencies of CD25+, CD69+ and TSLPR+ ILC2 were higher in AI compared to the NI (p<0.01). Additionally, egg burden was positively correlated with CD69+ ILC2 frequencies (r=0.67; p=0.005). Tryptase alpha/beta 1 (TPSAB1), GP6 and several plasma proteins associated with cell growth and granulocyte chemotaxis were highly expressed in the AI group (p<0.05). Interestingly, TPSAB1 levels were positively correlated with ILC2 expressing activation markers frequencies, egg burden and IgE levels against Ascaris.DiscussionAscaris infection is associated with increased expression of ILC2 activation markers and TPSAB1, which may contribute to the type-2 response.

Lactobacillus rhamnosus RL-H3-005 and Pediococcus acidilactici RP-H3-006 ameliorate atopic dermatitis in offspring mice by modulating the gut microbiota

The increasing incidence of atopic dermatitis (AD) presents a public health issue, and thus there is an urgent need for safe and effective preventive strategies. In this study, a strategy to reduce the risk of AD in offspring by administering probiotics to the mother was explored. Female mice were given Lactobacillus rhamnosus RL-H3-005 (RL) and Pediococcus acidilactici RP-H3-006 (RP) during pregnancy and lactation period, and their inhibition effects on AD symptoms in offspring mice were evaluated. The results showed that supplementation with RL and RP during pregnancy and lactation period altered not only the gut microbiota community but also microbial community in milk in pregnant mice. Further study showed that pups from RL- and RP-treated pregnant mice had mild symptoms of AD, characterized by reduced epidermal thickness in the ear tissues and numbers of mast cells, which was associated with the reduction in secretory immunoglobulin A (sIgA), immunoglobulin E (IgE), IL-4, IL-5, IL-13, thymic stromal lymphopoietin (TSLP), and eosinophil cationic protein (Ecp). The underlying mechanism of RL and RP on the inhibition of AD symptom in offspring was closely associated with the alterations of the gut microbiota community in offspring, including an increase in Ligilactobacillus and Bacteroides. This study implies that RL and RP hold the potential to reduce the risk of AD in offspring via gut-mammary axis during the pregnancy and lactation period.

Interferon as an immunoadjuvant to enhance antibodies following influenza B infection and vaccination in ferrets

Despite annual vaccination, influenza B viruses (IBV) continue to cause significant morbidity and mortality in humans. We have found that IBV infection resulted in a weaker innate and adaptive immune response than influenza A viruses (IAV) in ferrets. To understand and overcome the weak immune responses to IBV in ferrets, we administered type-I or type-III interferon (IFN) to ferrets following infection or vaccination and evaluated their effects on the immune response. IFN signaling following viral infection plays an important role in the initial innate immune response and affects subsequent adaptive immune responses. In the respiratory tract, IFN lambda (IFNL) has regulatory effects on adaptive immunity indirectly through thymic stromal lymphopoietin (TSLP), which then acts on immune cells to stimulate the adaptive response. Following IBV infection or vaccination, IFN treatment (IFN-Tx) upregulated gene expression of early inflammatory responses in the upper respiratory tract and robust IFN, TSLP, and inflammatory responses in peripheral blood cells. These responses were sustained following challenge or vaccination in IFN-Tx animals. Serum IFNL and TSLP levels were enhanced in IFN-Tx animals following challenge/rechallenge over mock-Tx; however, this difference was not observed following vaccination. Antibody responses in serum of IFN-Tx animals following IBV infection or vaccination increased more quickly and to higher titers and were sustained longer than mock-Tx animals over 3 months. Following rechallenge of infected animals 3 months post treatment, antibody levels remained higher than mock-Tx. However, IFN-Tx did not have an effect on antibody responses following challenge of vaccinated animals. A strong direct correlation was found between TSLP levels and antibody responses following challenge-rechallenge and vaccination-challenge indicating it as a useful tool for predicting adaptive immune responses following IBV infection or vaccination. The effects of IFN on strengthening both innate and adaptive responses to IBV may aid in development of more effective treatments following infection and improved influenza vaccines.

Role of Thymic Stromal Lymphopoietin in the Pathophysiology of Asthma and Clinical and Biological Effects of Blockade With Tezepelumab.

The airway epithelium is the first line of defense of the respiratory system against the external environment. It plays an active role in the initiation of immune and allergic responses against potential hazards. Among the various specialized cells and cytokines that participate in epithelium-induced responses, alarmins are particularly interesting, given their ample role in mediating T2 and non-T2 inflammatory mechanisms involved in the pathogenesis of asthma. Thymic stromal lymphopoietin (TSLP) is an alarmin with broad effects in asthma that result from its widespread action on multiple cell types, including eosinophils, mast cells, dendritic cells, and group-2 innate lymphoid cells. Its role in allergy-mediated responses, eosinophilic inflammation, airway hyperresponsiveness, mucus hyperproduction, viral tolerance, and airway remodeling is of the utmost importance, as more comprehensive asthma assessments have been developed to explore these pathogenic features. Therefore, blockade with targeting molecules, such as monoclonal antibodies, has emerged as a promising therapeutic option, particularly in patients with multiple pathogenic pathways. In this review, we examine the roles of alarmins (mainly TSLP) in the pathogenesis of asthma and clinical expression and discuss the effects of inhibiting TSLP on several inflammatory and clinical outcomes. We also review the literature supporting treatment with anti-TSLP biologics and the unanswered questions and unmet needs associated with targeting alarmins in asthma.

Expression of Epithelial Alarmin Receptor on Innate Lymphoid Cells Type 2 in Eosinophilic Chronic Obstructive Pulmonary Disease.

Studies have shown that eosinophilic COPD (eCOPD) is a distinct phenotype of the disease. It is well established that innate lymphoid cells are involved in the development of eosinophilic inflammation. Interleukin(IL)-25, thymic stromal lymphopoietin (TSLP) and IL-33 are a group of cytokines produced by epithelium in response to danger signals, e.g., cigarette smoke, and potent activators of ILC2s. In the present study, we examined circulating and sputum ILC2 numbers and expression of intracellular IL-5 as well as receptors for TSLP, IL-33 and IL-25 by ILC2s in non-atopic COPD patients with and without (neCOPD) airway eosinophilic inflammation and healthy smokers. In addition, we examined the association between ILC2s and clinical indicators of COPD burden (i.e., symptom intensity and risk of exacerbations). ILC2s were enumerated in peripheral blood and induced sputum by means of flow cytometry. We noted significantly greater numbers of airway IL-5+ILC2s and TSLPR+ILC2s in eCOPD compared with neCOPD (p < 0.05 and p < 0.01, respectively) and HSs (p < 0.001 for both). In addition, we showed that IL-5+ILC2s, IL-17RB+ILC2s and ST2+ILC2s are significantly increased in the sputum of eCOPD patients compared with HSs. In all COPD patients, sputum ILC2s positively correlated with sputum eosinophil percentage (r = 0.48, p = 0.002). We did not find any significant correlations between sputum ILC2s and dyspnea intensity as measured by the modified Medical Research Council scale (mMRC) and symptom intensity measured by the COPD Assessment Test (CAT). These results suggest the involvement of epithelial alarmin-activated ILC2s in the pathobiology of eosinophilic COPD.

ACUTE EOSINOPHILIC APPENDICITIS IN A CHILD WITH NORMAL TOTAL LEUKOCYTE COUNT AND ABSOLUTE EOSINOPHILIC COUNT

Abstract Introduction/Objective Eosinophilic appendicitis is a rare condition with a reported incidence of 0.03% to 1.2%, and often presents with clinical manifestations indistinguishable from acute appendicitis. Eosinophilic appendicitis may be associated with a localized allergic phenomenon. Methods/Case Report We present a 13-year-old male with ~24-hour history of constipation who was brought to the emergency department because of right lower quadrant abdominal pain, nausea, and vomiting. He was afebrile and had no antecedent of atopy or parasitic infestation. Laboratory investigation revealed an elevated C-reactive protein: 0.7 mg/dL [0.0-0.3]; mildly decreased hemoglobin: 12.2 g/dL [12.6 -16.8]; normal white blood cell count: 9.7 x10 3/mcL [3.2-10.6]; eosinophil count:1.7% [&amp;lt;5] and mildly elevated monocyte count: 0.9 x103/mcL [0.2-0.7]. Ultrasound examination revealed a non-compressible 7mm in diameter hyperemic appendix. The laparoscopic appendectomy specimen measured 9.5 cm long by 0.8 cm in diameter. The serosa was focally congested and there was mild mural thickening but no obvious sign of active appendicitis. Microscopic examination showed focally abundant mucosal eosinophils and a considerable sprinkling of eosinophils throughout the muscularis propria. No intraluminal parasite or neutrophilic associated mucosal damage was seen. The final diagnosis was: Acute Eosinophilic Appendicitis. Results (if a Case Study enter NA) N/A Conclusion Among the many and still intriguing causes of appendicitis is acute eosinophilic appendicitis. Eosinophils exert homeostatic roles in the normal host and pathological eosinophil-mediated processes over different tissues and their varied milieu. While this patient did not have any evidence of allergy, parasitic infestation, or elevated eosinophilic count in his work up, the presentation of acute appendicitis without an increase in total leukocytic count may alert for the possibility of an eosinophilic appendicitis. Conceivably, eosinophil mediators, such as IL-5, IL-33, granulocyte–macrophage colony-stimulating factor, thymic stromal lymphopoietin, and eotaxin-1 determine eosinophil behavior in a rarified appendix microenvironment.

Regulation of Airway Epithelial-Derived Alarmins in Asthma: Perspectives for Therapeutic Targets.

Asthma is a chronic respiratory condition predominantly driven by a type 2 immune response. Epithelial-derived alarmins such as thymic stromal lymphopoietin (TSLP), interleukin (IL)-33, and IL-25 orchestrate the activation of downstream Th2 cells and group 2 innate lymphoid cells (ILC2s), along with other immune effector cells. While these alarmins are produced in response to inhaled triggers, such as allergens, respiratory pathogens or particulate matter, disproportionate alarmin production by airway epithelial cells can lead to asthma exacerbations. With alarmins produced upstream of the type 2 inflammatory cascade, understanding the pathways by which these alarmins are regulated and expressed is critical to further explore new therapeutics for the treatment of asthmatic patients. This review emphasizes the critical role of airway epithelium and epithelial-derived alarmins in asthma pathogenesis and highlights the potential of targeting alarmins as a promising therapeutic to improve outcomes for asthma patients.

Acetamiprid elicits oxidative stress, pro-inflammatory response, and cellular proliferation in human bronchial epithelial cells in vitro and in silico: alleviative implications of the mixture of heat-killed Lactobacillus strains

BackgroundAcetamiprid (ACE), a neonicotinoid insecticide, has been extensively used to control pests in agricultural and industrial environments. It has been reported that ACE is detrimental to the lungs. Nevertheless, the extent to which the activation of oxidative stress, inflammation, and cellular proliferation contributes to the pulmonary toxicity induced by ACE exposure remains insufficiently understood. This study explored the mechanism of toxicological consequences after ACE exposure in bronchial epithelial cells (BEAS-2B cells). The research also examined the potential ameliorative effects of the mixture of heat-killed Lactobacillus delbrueckii and Lactobacillus fermentum (HKL) on the toxicities of ACE.ResultsFollowing 14 days of exposure to ACE at 0.5 and 1 μM, oxidative stress was induced, as evidenced by the decreased levels of reduced glutathione, catalase, glutathione peroxidase, and superoxide dismutase, along with increased levels of malondialdehyde. Also, ACE exposure results in overexpression and raised protein levels of the IL-25, NF-κB1, NF-κB2, IL-33, TSLP, and NF-κB target genes, which induce inflammatory responses. In addition, ACE boosted Ki-67-positive BEAS-2B cells. The molecular docking of ACE with target genes and their proteins demonstrated a potent binding affinity, further supported by the presence of hydrophobic contacts, electrostatic interactions, and hydrogen bonds. The post-treatment of HKL following the ACE (1 μM) exhibited its antioxidant, anti-inflammatory, and antiproliferative activities in suppressing ACE-induced toxicity.ConclusionsOur research revealed that ACE toxicity in BEAS-2B cells is caused by driving oxidative stress, pro-inflammatory response, and cellular proliferation. This study would give us a strategy to alleviate ACE-induced lung impairment by heat-killed probiotic supplements. As a result, dietary supplements that contain these microorganisms may potentially be beneficial in countries with high levels of pesticide contamination.

IL-7Rα on CD4+ T cells is required for their survival and the pathogenesis of experimental autoimmune encephalomyelitis

BackgroundThe IL-7 receptor alpha (IL-7Rα) binds both IL-7 and thymic stromal lymphopoietin (TSLP). IL-7Rα is essential for the development and survival of naive CD4+ T cells and their differentiation to effector/memory CD4+ T cells. Mice lacking IL-7Rα have severe lymphopenia and are resistant to experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis. However, it has been reported that IL-7Rα on peripheral CD4+ T cells is disposable for their maintenance and EAE pathogenesis, which does not align with the body of knowledge on the role of IL-7Rα in the biology of CD4+ T cells. Given that a definitive study on this important topic is lacking, we revisited it using a novel approach, an inducible knockout of the IL-7Rα gene in CD4+ T cells.MethodsWe generated Il7rafl/fl/CD4CreERT2 double transgenic mouse line (henceforth CD4ΔIl7ra), susceptible to tamoxifen-induced knockout of the IL-7Rα gene in CD4+ T cells. CD4ΔIl7ra mice were immunized with MOG35 − 55 for EAE induction and monitored for disease development. The expression of IL-7Rα, CD4+ T cell numbers, and MOG35 − 55-specific CD4+ T cell response was evaluated in the central nervous system (CNS) and lymphoid tissues by flow cytometry. Additionally, splenocytes of CD4ΔIl7ra mice were stimulated with MOG35 − 55 to assess their proliferative response and cytokine production by T helper cells.ResultsLoss of IL-7Rα from the surface of CD4+ T cells in CD4ΔIl7ra mice was virtually complete several days after tamoxifen treatment. The loss of IL-7Rα in CD4+ T cells led to a gradual and substantial decrease in their numbers in both non-immunized and immunized CD4ΔIl7ra mice, followed by slow repopulation up to the initial numbers. CD4ΔIl7ra mice did not develop EAE. We found a decrease in the total numbers of TNF-, IFN-γ-, IL-17 A-, and GM-CSF-producing CD4+ T cells and regulatory T cells in the spleens and CNS of immunized CD4ΔIl7ra mice. Tracking MOG35 − 55-specific CD4+ T cells revealed a significant reduction in their numbers in CD4ΔIl7ra mice and decreased proliferation and cytokine production in response to MOG35 − 55.ConclusionOur study demonstrates that IL-7Rα on peripheral CD4+ T cells is essential for their maintenance, immune response, and EAE pathogenesis.

Thymic stromal lymphopoietin signaling in B cells from progenitors to plasma cells.

Thymic stromal lymphopoietin (TSLP) is an established pleotropic alarmin cytokine that is generated at barrier tissues to induce type 2 immune responses, but its role in regulating the diversity of B cells is poorly understood. Here, we will highlight the key findings that underpin our limited understanding of the role TSLP in modulating different stages of B cell development. We will also provide an overview of how TSLP drives B cell-mediated immune disease and how novel TSLP-blocking biologics could be used to modulate B cell responses. TSLP is critical for the regulation, diversity, and longevity of humoral immunity.

Emerging Biologic Therapies for the Treatment of Atopic Dermatitis.

Atopic dermatitis (AD) is a prevalent inflammatory skin disease having a significant impact on patients' quality of life. Conventional treatments, including topical therapies and systemic immunosuppressants, often have limited efficacy and long-term safety concerns. Emerging biologic therapies target specific immune pathways implicated in AD pathogenesis, offering new therapeutic options in a disease known for its complex immune pathomechanisms. This review focuses on novel biologics under investigation, particularly those targeting specific immune pathways such as interleukin-4 (IL-4), IL-13, IL-22, IL-31, thymic stromal lymphopoietin (TSLP), and OX40-OX40L axis. Interleukin-4 and IL-13 inhibitors aim to reduce Th2-driven inflammation, while IL-22 inhibitors focus on restoring skin barrier function. Interleukin-31 inhibitors help alleviate pruritus, a major symptom in AD. OX40-OX40L pathway inhibitors can selectively suppress the activity of pathogenic T cells, without inducing significant immunosuppression. Bispecific antibodies targeting both IL-4 and IL-31 pathways are emerging as potential dual-action treatment for AD. Thymic stromal lymphopoietin inhibitors offer a novel strategy to control inflammation. While many of these therapies offer promising safety and efficacy profiles, long-term studies and real-world data are essential to confirm their lasting impact. This review highlights the potential of these emerging systemic therapies to continue transforming AD management and improve patient outcomes.

MERS-CoV Infection and Its Impact on the Expression of TSLP Cytokine and IgG Antibodies: An In Vivo and In Vitro Study.

Thymic stromal lymphopoietin (TSLP) is a proinflammatory cytokine produced by epithelial cells that is involved in the activation of allergic disorders. To date, no study has examined TSLP induction during Middle East respiratory syndrome coronavirus (MERS-CoV) infection. Herein, we aimed to study the effects of the recombinant spike protein of MERS-CoV on TSLP production. Additionally, the effects of recombinant human TSLP (rhTSLP) on B cell survival and antibody production were investigated. B cells were separated using the Human B Cell Enrichment Kit, and B cell survival was measured using the WST-1 Assay Kit. Enzyme-linked immunosorbent assay (ELISA) was used to measure TSLP levels in the sera of both MERS-CoV-infected (n=4; median age, 53 years) and healthy individuals (n=5; median age, 35 years). We showed that the group of infected patients had significantly higher levels of TSLP than healthy controls (37.6 pg/mL vs 19.8 pg/mL, *p<0.05). The levels of TSLP in A549 cells were remarkably increased after 48h of stimulation with recombinant full-length spike protein (rSP) (32.2 pg/mL, p=0.01). B cell survival was greatly enhanced by rhTSLP alone or in combination with rSP (0.02 vs 0.046, and 0.045; **p<0.01, respectively). Our data also showed a significant synergistic effect of rhTSLP and rSP on the augmented response of IgG antibodies against the spike protein of MERS-CoV compared with unstimulated cells (0.156 vs 0.22; *p<0.05). TSLP production is induced in vivo after MERS-CoV infection and in vitro after treatment with the rSP of MERS-CoV, which has a significant effect on the survival of B cells. Our data suggest that TSLP can be used as a strong mucosal adjuvant for vaccine development against MERS-CoV infection. However, further investigation is required to study the functional role of TSLP in MERS-CoV infection.

Type 2 cytokine-JAK1 signaling is involved in the development of dry-skin induced mechanical alloknesis

BackgroundMechanical alloknesis (m-alloknesis) is itch hypersensitivity induced by normally innocuous stimuli. It is sometimes observed in dry skin based itch-related diseases such as atopic dermatitis (AD), and often triggers the vicious itch-scratch cycle. The acetone-ether and water (AEW) mouse model mimics dry skin induced m-alloknesis, yet its underlying mechanism remains unclear. Janus kinase (JAK) inhibitors are used to treat AD, but their effects on m-alloknesis are not fully known. ObjectiveTo reveal the effects of various oral JAK inhibitors on m-alloknesis and their action points, using AEW model. MethodsAEW model was prepared by treatment with a mixture of acetone-ether, and they were orally administrated a JAK1/2 inhibitor baricitinib, a selective JAK1 inhibitor abrocitinib, or a JAK2 selective inhibitor AZ960, and evaluated m-alloknesis score as the total number of scratching responses in 30 mechanical stimulations. To further elucidate the mechanism of action, IL-4, IL-13 or thymic stromal lymphopoietin (TSLP) or their neutralizing antibodies were also applied to mice. In addition, the levels of these cytokines in mouse skin were measured using multiple immunoassays. ResultsAll of JAK inhibitors effectively reduced m-alloknesis, with abrocitinib demonstrating the most significant inhibition. The neutralizing antibodies against IL-4, IL-13, and TSLP inhibited m-alloknesis in AEW mice. Intradermal administration of IL-4, IL-13, or TSLP induced m-alloknesis, and abrocitinib effectively mitigated each cytokine-induced response. Highly sensitive assays detected IL-4, IL-13, IL-31 and TSLP in AEW-treated skin, with TSLP levels significantly increased. ConclusionType 2 cytokine-JAK1 signaling is involved in the development of m-alloknesis in dry skin.

Local receptor-interacting protein kinase 2 inhibition mitigates house dust mite-induced asthma.

House dust mite is the most frequent trigger of allergic asthma, with innate and adaptive immune mechanisms playing critical roles in outcomes. We recently identified the nucleotide-binding oligomerisation domain 1 (NOD1)/receptor-interacting serine/threonine protein kinase 2 (RIPK2) signalling pathway as a relevant contributor to murine house dust mite-induced asthma. This study aimed to evaluate the effectiveness of a pharmacological RIPK2 inhibitor administered locally as a preventive and therapeutic approach using a house dust mite-induced asthma model in wild-type and humanised NOD1 mice harbouring an asthma-associated risk allele, and its relevance using air-liquid interface epithelial cultures from asthma patients. A RIPK2 inhibitor was administered intranasally either preventively or therapeutically in a murine house dust mite-induced asthma model. Airway hyperresponsiveness, bronchoalveolar lavage composition, cytokine/chemokine expression and mucus production were evaluated, as well as the effect of the inhibitor on precision-cut lung slices. Furthermore, the inhibitor was tested on air-liquid interface epithelial cultures from asthma patients and controls. While local preventive administration of the RIPK2 inhibitor reduced airway hyperresponsiveness, eosinophilia, mucus production, T-helper type 2 cytokines and interleukin 33 (IL-33) in wild-type mice, its therapeutic administration failed to reduce the above parameters, except IL-33. By contrast, therapeutic RIPK2 inhibition mitigated all asthma features in humanised NOD1 mice. Results in precision-cut lung slices emphasised an early role of thymic stromal lymphopoietin and IL-33 in the NOD1-dependent response to house dust mite, and a late effect of NOD1 signalling on IL-13 effector response. RIPK2 inhibitor downregulated thymic stromal lymphopoietin and chemokines in house dust mite-stimulated epithelial cultures from asthma patients. These data support that local interference of the NOD1 signalling pathway through RIPK2 inhibition may represent a new therapeutic approach in house dust mite-induced asthma.

Oral Administration of Taurodeoxycholate, A GPCR19 Agonist, Effectively Ameliorates Atopic Dermatitis in A Mouse Model.

Atopic dermatitis (AD) is the most prevalent chronic inflammatory skin disorder, characterised by intense pruritus and recurrent eczematous lesions. Recently, the US FDA has approved Janus kinase (JAK) inhibitors for oral treatment in AD patients. However, oral immunomodulatory agents have demonstrated adverse effects. In previous studies, we demonstrated the efficacy of topical taurodeoxycholate (TDCA), a G protein-coupled receptor 19 (GPCR19) agonist, on AD. In this study, we further evaluated the efficacy of orally administered TDCA on MC903- and dinitrochlorobenzene (DNCB)-induced AD mouse models. Oral administration of TDCA significantly ameliorated AD symptoms and reduced both epidermal and dermal thickness. Additionally, oral TDCA treatment inhibited the infiltration of myeloid and lymphoid cells into AD lesions. TDCA also suppressed the expression of thymic stromal lymphopoietin (TSLP), interleukin (IL)-4, IL-13, IL-33, IL-1β, tumour necrosis factor-alpha (TNF-α) and chemokine (C-C motif) ligand 17 in the skin and blood. Given the previously demonstrated safety profiles of TDCA, oral TDCA may offer a beneficial and safer alternative for AD patients.

IL-7-dependent and -independent lineages of IL-7R-dependent human T cells.

Infants with biallelic IL7R loss-of-function variants have severe combined immune deficiency (SCID) characterized by the absence of autologous T lymphocytes, but normal counts of circulating B and NK cells (T-B+NK+ SCID). We report 6 adults (aged 22 to 59 years) from 4 kindreds and 3 ancestries (Colombian, Israeli Arab, Japanese) carrying homozygous IL7 loss-of-function variants resulting in combined immunodeficiency (CID). Deep immunophenotyping revealed relatively normal counts and/or proportions of myeloid, B, NK, and innate lymphoid cells. By contrast, the patients had profound T cell lymphopenia, with low proportions of innate-like adaptive mucosal-associated invariant T and invariant NK T cells. They also had low blood counts of T cell receptor (TCR) excision circles, recent thymic emigrant T cells and naive CD4+ T cells, and low overall TCR repertoire diversity, collectively indicating impaired thymic output. The proportions of effector memory CD4+ and CD8+ T cells were high, indicating IL-7-independent homeostatic T cell proliferation in the periphery. Intriguingly, the proportions of other T cell subsets, including TCRγδ+ T cells and some TCRαβ+ T cell subsets (including Th1, Tfh, and Treg) were little affected. Peripheral CD4+ T cells displayed poor proliferation, but normal cytokine production upon stimulation with mitogens in vitro. Thus, inherited IL-7 deficiency impairs T cell development less severely and in a more subset-specific manner than IL-7R deficiency. These findings suggest that another IL-7R-binding cytokine, possibly thymic stromal lymphopoietin, governs an IL-7-independent pathway of human T cell development.