Tezepelumab in patients with allergic and eosinophilic asthma

Asthma is a heterogeneous disease commonly driven by allergic and/or eosinophilic inflammation, both of which may be present in severe disease. Most approved biologics for severe asthma are indicated for specific phenotypes and target individual downstream type 2 components of the inflammatory cascade. Tezepelumab, a human monoclonal antibody (immunoglobulin G2λ), binds specifically to thymic stromal lymphopoietin (TSLP), an epithelial cytokine that initiates and sustains allergic and eosinophilic inflammation in asthma. By blocking TSLP, tezepelumab has demonstrated efficacy across known asthma phenotypes and acts upstream of all current clinically used biomarkers. In a pooled analysis of the phase 2b PATHWAY (NCT02054130) and phase 3 NAVIGATOR (NCT03347279) studies, compared with placebo, tezepelumab reduced the annualized asthma exacerbation rate over 52 weeks by 62% (95% confidence interval [CI]: 53, 70) in patients with perennial aeroallergen sensitization (allergic asthma); by 71% (95% CI: 62, 78) in patients with a baseline blood eosinophil count ≥300 cells/μL; and by 71% (95% CI: 59, 79) in patients with allergic asthma and a baseline blood eosinophil count ≥300 cells/μL. This review examines the efficacy and mode of action of tezepelumab in patients with allergic asthma, eosinophilic asthma and coexisting allergic and eosinophilic phenotypes.

Multifactorial Causes and Consequences of TLSP Production, Function, and Release in the Asthmatic Airway

Disruption of the airway epithelium triggers a defensive immune response that begins with the production and release of alarmin cytokines. These epithelial-derived alarmin cytokines, including thymic stromal lymphopoietin (TSLP), are produced in response to aeroallergens, viruses, and toxic inhalants. An alarmin response disproportionate to the inhaled trigger can exacerbate airway diseases such as asthma. Allergens inhaled into previously sensitized airways are known to drive a T2 inflammatory response through the polarization of T cells by dendritic cells mediated by TSLP. Harmful compounds found within air pollution, microbes, and viruses are also triggers causing airway epithelial cell release of TSLP in asthmatic airways. The release of TSLP leads to the development of inflammation which, when unchecked, can result in asthma exacerbations. Genetic and inheritable factors can contribute to the variable expression of TSLP and the risk and severity of asthma. This paper will review the various triggers and consequences of TSLP release in asthmatic airways.

Vernix caseosa reveals mechanistic clues linking maternal obesity to atopic dermatitis pathogenesis

BACKGROUND

Maternal overweight and obesity have been associated with an increased risk of atopic dermatitis (AD) in the offspring, but the underlying mechanisms are unclear. Vernix caseosa (VC) is a proteolipid material covering the fetus produced during skin development. However, whether maternal prepregnancy weight excess influences fetal skin development is unknown. Characterizing the VC of newborns from mothers with prepregnancy overweight and obesity might reveal AD-prone alterations during fetal skin development.

OBJECTIVE

We sought to explore AD biomarkers and staphylococcal loads in VC from the offspring of mothers who were overweight/obese (O/O) before pregnancy versus in those from offspring of normal weight mothers.

METHODS

The VC of newborns of 14 O/O and 12 normal weight mothers were collected immediately after birth. Biomarkers were determined by ELISA and staphylococcal species by quantitative PCR.

RESULTS

The VC from the O/O group showed decreased expression of skin barrier proteins (filaggrin and loricrin) and increased levels of proinflammatory biomarkers (IgA, thymic stromal lymphopoietin [TSLP], S100A8, IL-25, and IL-33). No differences in concentrations of antimicrobial peptides and enzymes were detected. The VC from the O/O group had a lower Staphylococcus epidermidis and Staphylococcus hominis commensal bacterial load, whereas Staphylococcus aureus bacterial load was not significantly different between the 2 groups. Maternal body mass index was negatively correlated with VC filaggrin expression and S epidermidis load and was positively associated with TSLP concentration. One-year follow-up established that the offspring of O/O mothers had a higher incidence of AD that was specifically linked with decreased VC filaggrin expression and lower S epidermidis load.

CONCLUSIONS

VC from neonates of mothers with prepregnancy overweight and obesity exhibit skin barrier molecular alterations and staphylococcal dysbiosis that suggest early mechanistic clues to this population's increased risk of AD.

Antibody targeting TSLP suppresses DSS-induced colitis and activation of the JAK2/STAT5 pathway in mice

There is currently no safe or effective treatment for inflammatory bowel disease (IBD), which is defined as recurrent and persistent intestinal inflammation. Thymic stromal lymphopoietin (TSLP) has been shown to be associated with the pathogenesis of IBD, and the JAK2/STAT5 signalling pathway has demonstrated much promise as a novel therapeutic target for IBD. In this study, we first evaluated levels of TSLP in dextran sodium sulphate (DSS)-induced IBD mice. Second, we applied tezepelumab, an anti-TSLP monoclonal antibody (20 μg per mouse, intraperitoneally), to DSS-induced IBD mice and quantified the signs of histopathological change, intestinal inflammation, and integrity of the mucosal barrier. In addition, the effect of DSS and/or tezepelumab on the phosphorylation of the JAK/STAT pathway was investigated. TSLP expression levels were elevated in DSS-induced IBD mice, whereas TSLP antibody treatment suppressed the pathological features associated with IBD and alleviated intestinal inflammation and mucosal barrier disruption. Moreover, level of phosphorylated JAK2/STAT5 were increased in DSS-induced IBD mice, but were strongly decreased in the presence of tezepelumab. Our findings suggest that targeting TSLP via the JAK2/STAT5 signalling pathway may be an effective approach for the treatment of IBD.

Tezepelumab: an anti-thymic stromal lymphopoietin monoclonal antibody for the treatment of asthma

Asthma is a common chronic respiratory disease in which epithelial cytokines and airway inflammation play critical pathophysiological roles. Thymic stromal lymphopoietin (TSLP), an epithelial cytokine, is central in the initiation and persistence of airway inflammation in asthma. Tezepelumab is a human immunoglobulin G2λ (IgG2λ) monoclonal antibody developed for treating moderate-to-severe asthma by specifically binding to TSLP and preventing its binding to the TSLP receptor on inflammatory cells. In this narrative review, we describe the results of clinical trials that evaluated the pharmacokinetics, pharmacodynamics, efficacy and safety of tezepelumab in patients with moderate-to-severe asthma. We also introduce the ongoing clinical trials in patients with asthma as well as future trials investigating the use of tezepelumab for other indications.

TSLP Induces Epithelial-Mesenchymal Transition in Nasal Epithelial Cells From Allergic Rhinitis Patients Through TGF-β1/Smad2/3 Signaling

BACKGROUND

Airway remodeling is demonstrated in Asian patients with allergic rhinitis (AR). The epithelial-mesenchymal transition (EMT) is one of the key mechanisms underlying airway remodeling. Thymic stromal lymphopoietin (TSLP) is an important contributor to airway remodeling. Although increased TSLP is found in AR, little is known about whether TSLP is involved in airway remodeling through induction of the EMT.

OBJECTIVE

We investigated the effect of TSLP on the EMT in human nasal epithelial cells (HNECs) from AR patients.

METHODS

Human nasal epithelial cells from AR patients were stimulated with TSLP in the absence or presence of the preincubation with a selective inhibitor of transforming growth factor beta 1 (TGF-β1) receptor (SB431542). The expression of TGF-β1 in the cells was evaluated by using real-time polymerase chain reaction, Western blotting, and immunocytochemistry. Western blotting and immunocytochemistry were used to assay EMT markers including vimentin, fibroblast-specific protein 1 (FSP1) and E-cadherin, small mothers against decapentaplegic homolog2/3 (Smad2/3), and phosphorylated Smad2/3 in the cells. The levels of extracellular matrix components such as collagens I and III in supernatants were measured by enzyme-linked immunoassay. Morphological changes of the cells were observed under inverted phase-contrast microscope.

RESULTS

A concentration-dependent increase of TGF-β1 mRNA and protein was observed following stimulation with TSLP. Furthermore, TSLP decreased the expression of E-cadherin protein, but upregulated the production of FSP1 and vimentin proteins along with increased levels of collagens I and III, and the morphology of the cells was transformed into fibroblast-like shape. Additionally, a significant increase was found in phosphorylation of Smad2/3 protein. However, these effects were reversed by SB431542 preincubation.

CONCLUSION

TSLP-induced HNECs to undergo the EMT process via TGF-β1-mediated Smad2/3 activation. TSLP is an activator of the EMT in HNECs and might be a potential target for inhibiting EMT and reducing airway remodeling in AR.

Association of Periodontitis and Atopic Dermatitis with the Levels of IL-13, IL-31, and TSLP in the Gingival Crevicular Fluid

Emerging epidemiological evidence links atopic dermatitis (AD) and periodontitis, although the mechanisms remain unclear. Th2-derived cytokines are key in the development of both diseases, and different gingival crevicular fluid (GCF) profiles among healthy and diseased subjects have been previously reported. This case-control study examined the GCF levels of interleukins (IL)-13, IL-31, and thymic stromal lymphopoietin (TSLP) in 29 subjects with moderate-to-severe AD and 33 controls. All subjects underwent comprehensive clinical and oral evaluations, followed by GCF collection. GCF levels of IL-13, IL-31, and TSLP were assessed using a multiplex-bead immunoassay. Demographic and periodontal parameters were similar among groups (p > 0.05). The GCF levels of IL-31 and TSLP were higher in AD subjects compared to controls (p < 0.05), whereas no significant differences in the GCF levels of IL-13 were noticed (p = 0.377). Moderate-to-severe AD was positively associated with the GCF levels of IL-31 and TSLP, whereas severe periodontitis was negatively associated with IL-31 (p < 0.05). The GCF levels of IL-13 showed no significant associations with either condition (p = 0.689). There was no significant interaction between AD and periodontitis for IL-31 (p < 0.869). These results suggest that AD and periodontitis independently influence the GCF levels of IL-31 in opposing ways, whereas AD alone influences the levels of TSLP.

Serum alarmins and the risk of incident interstitial lung disease in rheumatoid arthritis

OBJECTIVES

To quantify associations of serum alarmins with risk of rheumatoid arthritis-associated interstitial lung disease (RA-ILD).

METHODS

Using serum collected at enrolment, three alarmins (interleukin [IL]-33, thymic stromal lymphopoietin [TSLP], and IL-25) were measured in a multicentre prospective RA cohort. ILD was classified using systematic medical record review. Cross-sectional associations of log-transformed (IL-33, TSLP) or quartile (IL-25) values with RA-ILD at enrolment (prevalent RA-ILD) were examined using logistic regression, while associations with incident RA-ILD developing after enrolment were examined using Cox proportional hazards. Covariates in multivariate models included age, sex, race, smoking status, RA disease activity score, and anti-cyclic citrullinated antibody positivity.

RESULTS

Of 2,835 study participants, 115 participants (4.1%) had prevalent RA-ILD at baseline and an additional 146 (5.1%) developed incident ILD. There were no associations between serum alarmin concentrations and prevalent ILD in unadjusted or adjusted logistic regression models. In contrast, there was a significant inverse association between IL-33 concentration and the risk of developing incident RA-ILD in unadjusted (HR 0.73 per log-fold increase; 95% CI 0.57-0.95; p= 0.018) and adjusted (HR 0.77; 95% CI 0.59-1.00, p= 0.047) models. No significant associations of TSLP or IL-25 with incident ILD were observed.

CONCLUSIONS

In this study, we observed a significant inverse association between serum IL-33 concentration and the risk of developing incident RA-ILD, but no associations with prevalent ILD. Additional investigation is required to better understand the mechanisms driving this relationship and how serum alarmin IL-33 assessment might contribute to clinical risk stratification in patients with RA.

Type III interferon exerts thymic stromal lymphopoietin in mediating adaptive antiviral immune response

Previously, it was believed that type III interferon (IFN-III) has functions similar to those of type I interferon (IFN-I). However, recently, emerging findings have increasingly indicated the non-redundant role of IFN-III in innate antiviral immune responses. Still, the regulatory activity of IFN-III in adaptive immune response has not been clearly reported yet due to the low expression of IFN-III receptors on most immune cells. In the present study, we reviewed the adjuvant, antiviral, antitumor, and disease-moderating activities of IFN-III in adaptive immunity; moreover, we further elucidated the mechanisms of IFN-III in mediating the adaptive antiviral immune response in a thymic stromal lymphopoietin (TSLP)-dependent manner, a pleiotropic cytokine involved in mucosal adaptive immunity. Research has shown that IFN-III can enhance the antiviral immunogenic response in mouse species by activating germinal center B (GC B) cell responses after stimulating TSLP production by microfold (M) cells, while in human species, TSLP exerts OX40L for regulating GC B cell immune responses, which may also depend on IFN-III. In conclusion, our review highlights the unique role of the IFN-III/TSLP axis in mediating host adaptive immunity, which is mechanically different from IFN-I. Therefore, the IFN-III/TSLP axis may provide novel insights for clinical immunotherapy.

Tezepelumab Efficacy in Patients with Severe, Uncontrolled Asthma with Comorbid Nasal Polyps in NAVIGATOR

Purpose

Tezepelumab, a human monoclonal antibody, blocks thymic stromal lymphopoietin. In the phase 3 NAVIGATOR study (NCT03347279), tezepelumab reduced annualized asthma exacerbation rates (AAERs) versus placebo, irrespective of baseline disease characteristics, and improved lung function and symptom control versus placebo in adults and adolescents with severe, uncontrolled asthma. We assessed the efficacy of tezepelumab in patients with severe asthma with or without nasal polyps (NPs) in the 2 years before randomization in NAVIGATOR.

Methods

Patients with severe asthma (N=1059) were randomized (1:1) and received tezepelumab 210 mg or placebo every 4 weeks subcutaneously for 52 weeks. Prespecified exploratory analyses included: AAER over 52 weeks and changes from baseline to week 52 in pre-bronchodilator forced expiratory volume in 1 second, Sino-Nasal Outcome Test (SNOT)-22 scores, and asthma control and health-related quality life (HRQoL) outcomes in NP subgroups. Changes from baseline in fractional exhaled nitric oxide (FeNO), blood eosinophil counts, total immunoglobulin E (IgE), eosinophil-derived neurotoxin (EDN), matrix metalloproteinase-10 (MMP-10), and serum interleukin (IL)-5, IL-6, IL-8 and IL-13 were assessed (post hoc).

Results

Tezepelumab reduced the AAER over 52 weeks versus placebo by 85% (95% confidence interval [CI]: 72, 92; n=118) and 51% (95% CI: 40, 60; n=941) in patients with and without NPs, respectively. At week 52, tezepelumab improved lung function, asthma control and HRQoL versus placebo in patients with and without NPs. Tezepelumab reduced SNOT-22 total scores (least-squares mean difference versus placebo [95% CI]) in patients with NPs at 28 weeks (-12.57 points [-19.40, -5.73]) and 52 weeks (-10.58 points [-17.75, -3.41]). At week 52, tezepelumab reduced blood eosinophil counts and FeNO, IgE, IL-5, IL-13, EDN and MMP-10 levels versus placebo, irrespective of NP status.

Conclusion

Tezepelumab resulted in clinically meaningful improvements in sino-nasal symptoms and asthma outcomes in patients with severe asthma with comorbid NPs.

Thymic Stromal Lymphopoietin (TSLP), Its Isoforms and the Interplay with the Epithelium in Allergy and Asthma

Thymic stromal lymphopoietin (TSLP) is a pleiotropic cytokine that has emerged as a critical player in the development and progression of allergy and asthma. It is primarily produced by epithelial cells and functions as a potent immune system activator. TSLP acts through interaction with its receptor complex, composed of the TSLP receptor (TSLPR) and interleukin-7 receptor alpha chain (IL-7Rα), activating downstream complex signalling pathways. The TSLP major isoform, known as long-form TSLP (lfTSLP), is upregulated in the airway epithelium of patients with allergic diseases. More research is warranted to explore the precise mechanisms by which short-form TSLP (sfTSLP) regulates immune responses. Understanding the dynamic interplay between TSLP and the dysfunctional epithelium provides insights into the mechanisms underlying allergy and asthma pathogenesis. Targeting TSLP represents an important therapeutic strategy, as it may upstream disrupt the inflammatory cascade and alleviate symptoms associated with allergic inflammation.

Efficacy of Tezepelumab in Severe, Uncontrolled Asthma: Pooled Analysis of the PATHWAY and NAVIGATOR Clinical Trials

Rationale: Tezepelumab reduced exacerbations in patients with severe, uncontrolled asthma across a range of baseline blood eosinophil counts and fractional exhaled nitric oxide levels, and irrespective of allergy status, in the phase 2b PATHWAY (Study to Evaluate the Efficacy and Safety of MEDI9929 [AMG 157] in Adult Subjects With Inadequately Controlled, Severe Asthma; NCT02054130) and phase 3 NAVIGATOR (Study to Evaluate Tezepelumab in Adults & Adolescents With Severe Uncontrolled Asthma; NCT03347279) trials. Objectives: To examine the efficacy and safety of tezepelumab in additional clinically relevant subgroups using pooled data from PATHWAY and NAVIGATOR. Methods: PATHWAY and NAVIGATOR were randomized, double-blind, placebo-controlled trials with similar designs. This pooled analysis included patients with severe, uncontrolled asthma (PATHWAY, 18-75 years old; NAVIGATOR, 12-80 years old) who received tezepelumab 210 mg or placebo subcutaneously every 4 weeks for 52 weeks. The annualized asthma exacerbation rate over 52 weeks and secondary outcomes were calculated in the overall population and in subgroups defined by inflammatory biomarker levels or clinical characteristics. Measurements and Main Results: Overall, 1,334 patients were included (tezepelumab, n = 665; placebo, n = 669). Tezepelumab reduced the annualized asthma exacerbation rate versus placebo by 60% (rate ratio, 0.40 [95% confidence interval, 0.34-0.48]) in the overall population, and clinically meaningful reductions in exacerbations were observed in tezepelumab-treated patients with type 2-high and type 2-low disease by multiple definitions. Tezepelumab reduced exacerbation-related hospitalization or emergency department visits and improved secondary outcomes compared with placebo overall and across subgroups. The incidence of adverse events was similar between treatment groups. Conclusions: Tezepelumab resulted in clinically meaningful reductions in exacerbations and improvements in other outcomes in patients with severe, uncontrolled asthma, across clinically relevant subgroups. Clinical trials registered with www.clinicaltrials.gov (NCT02054130 [PATHWAY], NCT03347279 [NAVIGATOR]).

IL-31-generating network in atopic dermatitis comprising macrophages, basophils, thymic stromal lymphopoietin, and periostin

BACKGROUND

IL-31 is a type 2 cytokine involved in the itch sensation in atopic dermatitis (AD). The cellular origins of IL-31 are generally considered to be T_H2 cells. Macrophages have also been implicated as cellular sources of IL-31.

OBJECTIVE

We sought to determine the expression of IL-31 by macrophages and to elucidate the productive mechanisms and contributions to itch in AD skin lesions.

METHODS

Expression of IL-31 by macrophages, expressions of thymic stromal lymphopoietin (TSLP) and periostin, and presence of infiltrating basophils in human AD lesions were examined through immunofluorescent staining, and correlations were assessed. Furthermore, mechanisms of inducing IL-31-expressing macrophages were analyzed in an MC903-induced murine model for AD in vivo and in mouse peritoneal macrophages ex vivo.

RESULTS

A significant population of IL-31⁺ cells in human AD lesions was that of CD68⁺ cells expressing CD163, an M2 macrophage marker. The number of IL-31⁺/CD68⁺ cells correlated with epidermal TSLP, dermal periostin, and the number of dermal-infiltrating basophils. In the MC903-induced murine AD model, significant scratching behaviors with enhanced expressions of TSLP and periostin were observed, accompanied by massive infiltration of basophils and IL-31⁺/MOMA-2⁺/Arg-1⁺ cells. Blockade of IL-31 signaling with anti-IL-31RA antibody or direct depletion of macrophages by clodronate resulted in attenuation of scratching behaviors. To effectively reduce lesional IL-31⁺ macrophages and itch, basophil depletion was essential in combination with TSLP- and periostin-signal blocking. Murine peritoneal macrophages produced IL-31 when stimulated with TSLP, periostin, and basophils.

CONCLUSIONS

A network comprising IL-31-expressing macrophages, TSLP, periostin, and basophils plays a significant role in AD itch.

Crosstalk between ILC2s and Th2 cells varies among mouse models

Type 2 T helper (Th2) cells and group 2 innate lymphoid cells (ILC2s) provide protection against helminth infection and are involved in allergic responses. However, their relative importance and crosstalk during type 2 immune responses are still controversial. By generating and utilizing mouse strains that are deficient in either ILC2s or Th2 cells, we report that interleukin (IL)-33-mediated ILC2 activation promotes the Th2 cell response to papain; however, the Th2 cell response to ovalbumin (OVA)/alum immunization is thymic stromal lymphopoietin (TSLP) dependent but independent of ILC2s. During helminth infection, ILC2s and Th2 cells collaborate at different phases of the immune responses. Th2 cells, mainly through IL-4 production, induce the expression of IL-25, IL-33, and TSLP, among which IL-25 and IL-33 redundantly promote ILC2 expansion. Thus, while Th2 cell differentiation can occur independently of ILC2s, activation of ILC2s may promote Th2 responses, and Th2 cells can expand ILC2s by inducing type 2 alarmins.

NOD2 Agonism Counter-Regulates Human Type 2 T Cell Functions in Peripheral Blood Mononuclear Cell Cultures: Implications for Atopic Dermatitis

Atopic dermatitis (AD) is known as a skin disease; however, T cell immunopathology found in blood is associated with its severity. Skin Staphylococcus aureus (S. aureus) and associated host-pathogen dynamics are important to chronic T helper 2 (Th2)-dominated inflammation in AD, yet they remain poorly understood. This study sought to investigate the effects of S. aureus-derived molecules and skin alarmins on human peripheral blood mononuclear cells, specifically testing Th2-type cells, cytokines, and chemokines known to be associated with AD. We first show that six significantly elevated Th2-related chemokine biomarkers distinguish blood from adult AD patients compared to healthy controls ex vivo; in addition, TARC/CCL17, LDH, and PDGF-AA/AB correlated significantly with disease severity. We then demonstrate that these robust AD-associated biomarkers, as well as associated type 2 T cell functions, are readily reproduced from healthy blood mononuclear cells exposed to the alarmin TSLP and the S. aureus superantigen SEB in a human in vitro model, including IL-13, IL-5, and TARC secretion as well as OX-40-expressing activated memory T cells. We further show that the agonism of nucleotide-binding oligomerization domain-containing protein (NOD)2 inhibits this IL-13 secretion and memory Th2 and Tc2 cell functional activation while inducing significantly increased pSTAT3 and IL-6, both critical for Th17 cell responses. These findings identify NOD2 as a potential regulator of type 2 immune responses in humans and highlight its role as an endogenous inhibitor of pathogenic IL-13 that may open avenues for its therapeutic targeting in AD.

Increased expression of long-isoform thymic stromal lymphopoietin is associated with rheumatoid arthritis and fosters inflammatory responses

Thymic stromal lymphopoietin (TSLP) is a pleiotropic cytokine that is involved in the pathogenesis of inflammatory diseases and asthma, but the expression and biological implications of the existence of two isoforms, long TSLP (lTSLP) and short TSLP (sTSLP), in RA have yet to be elucidated. Here we report that lTSLP is the predominant TSLP isoform in RA and active RA, whereas sTSLP is the major TSLP isoform in inactive RA and healthy controls. lTSLP expression is associated with disease activity, including 28-joint Disease Activity Score (DAS28) and erythrocyte sedimentation rate (ESR), as well as proinflammatory cytokine expression, irrespective of other laboratory parameters. Importantly, lTSLP alone or combined with LPS promotes the expression of proinflammatory cytokines IL-1β, IL-6, and IL-8 in PBMCs of RA, but restrains anti-inflammatory cytokine IL-10 expression in PBMCs of RA. Furthermore, we found that STAT5 signaling is involved in lTSLP-induced inflammatory accumulation in PBMCs of RA. Therefore, these results highlight the clinical significance of lTSLP in RA pathology and inflammatory response in acute-phase disease, which may provide a therapeutic target for RA.

The Protective Effect of a Functional Food Consisting of Astragalus membranaceus, Trichosanthes kirilowii, and Angelica gigas or Its Active Component Formononetin against Inflammatory Skin Disorders through Suppression of TSLP via MDM2/HIF1α Signaling Pathways

An herbal mixture (SH003) of Astragalus membranaceus, Trichosanthes kirilowii, and Angelica gigas exhibits therapeutic effects on carcinomas and immunosuppression. However, the role of JRP-SNF102, which is an advanced mixture of SH003, in regulating inflammatory responses is unexplored. We aim to substantiate the therapeutic potential of JRP-SNF102 and its active component, formononetin (FMN), as a functional food that moderates inflammatory responses. The inhibitory effects of JRP-SNF102 or FMN on thymic stromal lymphopoietin (TSLP) levels were evaluated in phorbol 12-myristate 13-acetate (PMA) plus A23187-activated human mast cell line-1 (HMC-1) cells and a mouse model of PMA-induced ear edema. The JRP-SNF102 or FMN inhibited the secretion and mRNA expression of TSLP and vascular endothelial growth factor (VEGF) in the activated HMC-1 cells. The expression levels of murine double minute 2 (MDM2), hypoxia-inducible factor 1α (HIF1α), and NF-κB were also suppressed by JRP-SNF102 or FMN in the activated HMC-1 cells. The JRP-SNF102 or FMN inhibited TSLP and VEGF levels, attenuating redness and ear thickness in mice with acute ear edema; JRP-SNF102 or FMN reduced the expression levels of MDM2, HIF1α, and NF-κB in the ear tissues. These findings suggest the potential for JRP-SNF102 as a functional food in the treatment of inflammatory skin disorders through suppression of TSLP and VEGF.

Effects of combination treatment with tezepelumab and allergen immunotherapy on nasal responses to allergen: A randomized controlled trial

BACKGROUND

Thymic stromal lymphopoietin (TSLP) has been shown to play a central role in the initiation and persistence of allergic responses.

OBJECTIVE

We evaluated whether tezepelumab, a human monoclonal anti-TSLP antibody, improved the efficacy of subcutaneous allergen immunotherapy (SCIT) and promoted the development of tolerance in patients with allergic rhinitis.

METHODS

We conducted a double-blind parallel design trial in patients with cat allergy. A total of 121 patients were randomized to receive either intravenous tezepelumab plus subcutaneous cat SCIT, cat SCIT alone, tezepelumab alone, or placebo for 52 weeks, followed by 52 weeks of observation. Nasal allergen challenge (NAC), skin testing, and blood and nasal samples were obtained throughout the study.

RESULTS

At week 52, the NAC-induced total nasal symptom scores (TNSS) (calculated as area under the curve [AUC0-1h] and as peak score [Peak0-1h] during the first hour after NAC) were significantly reduced in patients receiving tezepelumab/SCIT compared to SCIT alone. At week 104, one year after stopping treatment, the primary end point TNSS AUC0-1h was not significantly different in the tezepelumab/SCIT group compared to SCIT alone, while TNSS Peak0-1h was significantly lower in those receiving combination treatment versus SCIT. Transcriptomic analysis of nasal epithelial samples demonstrated that treatment with the combination of SCIT/tezepelumab, but neither monotherapy, caused persistent downregulation of a gene network related to type 2 inflammation that was associated with improvement in NAC responses.

CONCLUSIONS

Inhibition of TSLP augments the efficacy of SCIT during therapy and may promote tolerance after a 1-year course of treatment. (ClinicalTrials.gov NCT02237196).

The Impact of Tezepelumab in Uncontrolled Severe Asthma: A Systematic Review of Randomized Controlled Trials

Asthma, a chronic illness, is characterized by inflammation and airway constriction. Uncontrolled severe asthma is related to poor quality of life and increased utilization of health resources. Conventional treatments are associated with a significant amount of adverse effects. Recent years have seen the identification of various molecular effectors and signaling pathways as interesting targets for the biological therapy of severe asthma that is resistant to current therapies. Because they only target some downstream components of the inflammatory response in asthma, leaving other components unaffected, current biologic treatments only lower the exacerbation rate by 50%. If we focus on the upstream mediators of the inflammatory response in asthma, it might have a greater effect and be more efficient. Tezepelumab is a human monoclonal IgG2 antibody that specifically binds to thymic stromal lymphopoietin (TSLP) at the level of its TSLPR (thymic stromal lymphopoietin receptor) binding site, inhibiting the interaction between human TSLP and TSLPR. It is being used to treat the cytokines on the respiratory epithelial layer known as "alarmins." It is the only biologic drug available for treating severe uncontrolled asthma, despite limitations in biomarker and phenotype. In light of recent developments, the lack of knowledge on tezepelumab prompts us to publish a comprehensive systematic review. We discovered that regardless of blood eosinophil level and fractional exhaled nitric oxide levels, tezepelumab dramatically lowers asthma exacerbation in patients with severe uncontrolled asthma when compared to placebo. Tezepelumab also lessens patients' demand for healthcare resources while improving clinical indicators of lung function, health-related quality of life, and asthma management in patients. Tezepelumab plays a role in enhancing pre-bronchodilator FEV1 and lowering blood eosinophil count and fractional exhaled nitric oxide in patients with or without chronic allergies (FeNO). There have been no reports of fatalities or severe adverse events connected to tezepelumab.

β-Caryophyllene Ameliorates 2,4-Dinitrochlorobenzene-Induced Atopic Dermatitis through the Downregulation of Mitogen-Activated Protein Kinase/EGR1/TSLP Signaling Axis

Atopic dermatitis (AD) is one of the most common inflammatory skin diseases accompanied by severe itching. β-caryophyllene (BCP), which displays anti-inflammatory activity, is a natural agonist of cannabinoid receptor 2. However, the therapeutic effects of BCP on atopic dermatitis (AD) remain poorly understood. The current study aimed to evaluate the topical therapeutic efficacy of BCP in an AD-like mouse model. Thymic Stromal Lymphopoietin (TSLP) is a keratinocyte-derived cytokine that drives AD pathogenesis. This study also investigated the effect of BCP on the interleukin 4 (IL-4)-induced expression of TSLP in HaCaT keratinocytes. We found that the topical application of BCP alleviated AD-like skin inflammation and inhibited the infiltration of proinflammatory cells into skin lesions. Moreover, the topical application of BCP reduced EGR1 (Early Growth Response 1) and TSLP expression in AD-like skin lesions. We also found that BCP inhibited IL-4-induced TSLP expression by downregulating mitogen-activated protein kinase (MAPK)-mediated EGR1 expression in HaCaT keratinocytes. These findings demonstrate that BCP ameliorates DNCB-induced AD-like skin lesions through the downregulation of the MAPK/EGR1/TSLP signaling axis. BCP may be applicable for developing topical therapeutic agents for chronic skin inflammatory diseases, such as AD.

Downregulation of deubiquitinating enzyme USP25 promotes the development of allergic rhinitis by enhancing TSLP signaling in the nasal epithelium

Ubiquitin-specific peptidase 25 (USP25) is a key deubiquitylase belonging to the USP superfamily that is primarily involved in inflammation and the immune response. Thymic stromal lymphopoietin (TSLP) is an epithelial-derived cytokine that is regarded as the master switch that initiates and maintains the type 2 immune response in allergic rhinitis (AR). However, the molecular mechanisms by which USP25 regulates TSLP signaling in the nasal epithelium in AR remain unclear. The present study assessed the protein expression levels of USP25 in the nasal epithelium of patients with AR. Moreover, USP25 knockout (KO) and wild-type (WT) mice were treated with ovalbumin (OVA) to establish a model of AR. The results of western blotting and immunohistochemistry in the present study demonstrated that the protein expression levels of USP25 were significantly decreased in the nasal mucosa of patients with AR and AR mice, whereas the protein expression levels of TSLP were significantly increased. Allergic inflammation was more severe in USP25 KO mice compared with WT mice exposed to OVA, as demonstrated by increased nose scratching and sneezing, increased eosinophil infiltration, goblet cell hyperplasia and enhanced T helper type 2 (Th2) cytokine production. The results of in vitro experiments demonstrated that silencing or overexpression of USP25 decreased or increased TNF receptor-associated factor 3 (TRAF3) protein expression levels, respectively, in human nasal epithelial cells, whereas TSLP protein expression levels were negatively associated with the expression of USP25 and TRAF3. In summary, USP25 downregulation enhanced TSLP signaling in the nasal mucosal epithelium via decreased TRAF3 expression, thereby exacerbating inflammation in AR. Therefore, USP25 may act as a novel therapeutic target in AR.

A Comparison for Type 2 Cytokines and Lesional Inflammatory Infiltrations in Bullous Pemphigoid and Atopic Dermatitis

Background

Bullous pemphigoid (BP) and atopic dermatitis (AD) are both type 2 inflammatory skin diseases with similar clinical features. Thymic stromal lymphopoietin (TSLP) is an epithelial-derived cytokine which is upregulated in AD. However, the expression of TSLP in BP and the correlation between TSLP and inflammatory infiltrations have not been fully studied.

Objective

To characterize the serum Th2 cytokines level and Th2 inflammatory cell infiltrations in BP and AD. To study TSLP levels in serum, blister fluids and expression in lesional skin in patients with BP and AD.

Methods

TSLP level in serum and blister fluids was measured by enzyme-linked immunosorbent assay (ELISA). Inflammatory cells (CD4+ T cells, CD8+ T cells, CD1a+ cells, eosinophils and mast cells) were stained immunohistochemically and quantified by image analysis.

Results

TSLP level was significantly increased in blister fluids of BP and was highly expressed in lesional skin of BP and AD. Serum levels of IL-6, IL-4, IL-22, IFN-γ and thymic activation regulates chemokines (TARC) were significantly higher in patients with BP and AD than in healthy controls. CD4+ T cells, CD8+ T cells and CD1a+ cells were significantly more in upper dermis of BP and AD lesions. Eosinophils were found more in BP lesions while mast cells were found more in AD lesions than in healthy controls. A distinct correlation was found between TSLP levels and the intensities of CD4+ T cells, CD1a+ cells infiltrations.

Conclusion

TSLP was significantly higher in blister fluids and skin lesions of BP, suggesting that it might contribute to the pathogenesis of BP. BP exhibited a similar type 2 immune response and a slight difference in cells infiltrations with AD.

Targeting TSLP in Asthma

Thymic stromal lymphopoietin (TSLP) is an epithelial cell-derived cytokine implicated in the initiation and persistence of inflammatory pathways in asthma. Released in response to a range of epithelial insults (eg, allergens, viruses, bacteria, pollutants, and smoke), TSLP initiates multiple downstream innate and adaptive immune responses involved in asthma inflammation. Inhibition of TSLP is postulated to represent a novel approach to treating the diverse phenotypes and endotypes of asthma. Tezepelumab, the TSLP inhibitor farthest along in clinical development, is a human monoclonal antibody (IgG2λ) that binds specifically to TSLP, preventing interactions with its heterodimeric receptor. Results of recently published phase 2 and 3 studies, reviewed in this article, provide evidence of the safety and efficacy of tezepelumab that builds on initial findings. Tezepelumab is safe, well tolerated, and provides clinically meaningful improvements in asthma control, including reduced incidence of exacerbations and hospitalizations in patients with severe asthma. Clinical benefits were associated with reductions in levels of a broad spectrum of cytokines (eg, interleukin [IL]-5, IL-13) and baseline biomarkers (eg, blood eosinophils, immunoglobulin [Ig]E, fractional exhaled nitric oxide [FeNO]) and were observed across a range of severe asthma phenotypes (ie, eosinophilic and non-eosinophilic). These data strengthen the notion that anti-TSLP elicits broad inhibitory effects on pathways that are key to asthma inflammation rather than on narrower inhibition of individual downstream factors. This review presents the rationale for targeting TSLP to treat asthma, as well as the clinical effects of TSLP blockade on asthma outcomes, biomarkers of disease activity, airway inflammation, lung physiology, and patient symptoms.

Alarmins and innate lymphoid cells 2 activation: A common pathogenetic link connecting respiratory syncytial virus bronchiolitis and later wheezing/asthma?

Severe respiratory syncytial virus (RSV) infection in infancy is associated with increased risk of recurrent wheezing in childhood. Both acute and long-term alterations in airway functions are thought to be related to inefficient antiviral immune response. The airway epithelium, the first target of RSV, normally acts as an immunological barrier able to elicit an effective immune reaction but may also be programmed to directly promote a Th2 response, independently from Th2 lymphocyte involvement. Recognition of RSV transcripts and viral replication intermediates by bronchial epithelial cells brings about release of TSLP, IL-33, HMGB1, and IL-25, dubbed "alarmins." These epithelial cell-derived proteins are particularly effective in stimulating innate lymphoid cells 2 (ILC2) to release IL-4, IL-5, and IL-13. ILC2, reflect the innate counterparts of Th2 cells and, when activate, are potent promoters of airway inflammation and hyperresponsiveness in RSV bronchiolitis and childhood wheezing/asthma. Long-term epithelial progenitors or persistent epigenetic modifications of the airway epithelium following RSV infection may play a pathogenetic role in the short- and long-term increased susceptibility to obstructive lung diseases in response to RSV in the young. Additionally, ILC2 function may be further regulated by RSV-induced changes in gut microbiota community composition that can be associated with disease severity in infants. A better understanding of the alarmin-ILC interactions in childhood might provide insights into the mechanisms characterizing these immune-mediated diseases and indicate new targets for prevention and therapeutic interventions.

Thymic Stromal Lymphopoietin Induction Suppresses Lung Cancer Development

Simple Summary

The recurrence rate for lung cancer is high after the removal of the primary tumor. Herein, we demonstrate the potential of immunotherapy against lung cancer by examining the impact of Thymic Stromal Lymphopoietin (TSLP) cytokine induction on early lung cancer development. TSLP induction suppresses the development of invasive lung tumors in a mouse model of spontaneous lung cancer. This cancer suppression is dependent on CD4⁺ T cells, which highlights the role of adaptive immune response in protection against lung cancer progression.

Abstract

Lung cancer is the leading cause of cancer deaths in the United States and across the world. Immunotherapies, which activate tumor-infiltrating cytotoxic T lymphocytes, have demonstrated efficacy for the treatment of advanced-stage lung cancer. However, the potential for harnessing the immune system against the early stages of lung carcinogenesis to prevent cancer development and recurrence remains unexplored. Using a mouse model of lung adenocarcinoma, we investigated the effects of thymic stromal lymphopoietin (TSLP) induction on early cancer development in the lungs. Herein, we demonstrate that systemic TSLP induction suppressed spontaneous lung cancer development in Kras^G12D mice. TSLP drove a significant CD4⁺ T cell response to block lung cancer progression from atypical alveolar hyperplasia to adenocarcinoma. Our findings suggest that TSLP can be used in the early stages of lung cancer development to trigger a lasting immunity in the tissue and prevent the development of advanced disease.

Saikosaponin A and Saikosaponin C Reduce TNF-α-Induced TSLP Expression through Inhibition of MAPK-Mediated EGR1 Expression in HaCaT Keratinocytes

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases worldwide, characterized by intense pruritus and eczematous lesions. Aberrant expression of thymic stromal lymphopoietin (TSLP) in keratinocytes is associated with the pathogenesis of AD and is considered a therapeutic target for the treatment of this disease. Saikosaponin A (SSA) and saikosaponin C (SSC), identified from Radix Bupleuri, exert anti-inflammatory effects. However, the topical effects of SSA and SSC on chronic inflammatory skin diseases are unclear. In this study, we investigated the effects of SSA and SSC on TSLP suppression in an AD-like inflammatory environment. We observed that SSA and SSC suppressed tumor necrosis factor-α-induced TSLP expression by downregulating the expression of the transcription factor early growth response 1 (EGR1) via inhibition of the extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase 1/2, and p38 mitogen-activated protein kinase pathways. We also confirmed that topical application of SSA or SSC reduced AD-like skin lesions in BALB/c mice challenged with 2,4-dinitrochlorobenzene. Our findings suggest that suppression of EGR1-regulated TSLP expression in keratinocytes might be attributable to the anti-inflammatory effects of SSA and SSC in AD-like skin lesions.

Involvement of autophagy in exacerbation of eosinophilic airway inflammation in a murine model of obese asthma

Obesity is a common comorbidity in patients with asthma, and obese asthma patients present the most refractory phenotype among patients with severe asthma. Similar to the observations in non-obese asthma patients, clinical studies have revealed heterogeneity in obese asthma patients, including the occurrences of T helper (Th)2-high and Th2-low phenotypes. However, the mechanisms underlying obesity-related asthma are not completely understood. Though macroautophagy/autophagy is involved in asthma and obesity, its role in obesity-associated asthma is unknown. We hypothesized that autophagy is involved in the pathogenesis of obese asthma. For our investigations, we used high-fat diet-induced Atg5 (autophagy related 5)-deficient mice and epithelial cell-specific atg5^−/− (Scgb1a1/CCSP-atg5^−/−) obesity-induced mice. House dust mite (HDM)-sensitized atg5^−/− obese mice exhibited marked eosinophilic inflammation and airway hyper-reactivity (AHR), compared to wild-type (WT) obese mice. Analyses of atg5^−/− obese mice showed increased levels of Th2 cells but not ILC2s together with elevated expression of Th2 cytokines in the lung. In response to the HDM challenge, activated epithelial autophagy was observed in lean but not obese WT mice. Epithelium-specific deletion of Atg5 induced eosinophilic inflammation in Scgb1a1/CCSP-atg5^−/− obese mice, and genetic analyses of epithelial cells from HDM-immunized atg5^−/− obesity-induced mice showed an elevated expression of thymic stromal lymphopoietin (TSLP) and IL33. Notably, HDM-sensitized atg5^−/− mice developed TSLP- and IL33-dependent eosinophilic inflammation and AHR. Our results suggest that autophagy contributes to the exacerbation of eosinophilic inflammation in obese asthma. Modulations of autophagy may be a therapeutic target in obesity-associated asthma.

Abbreviations: AHR: airway hyper-reactivity; BAL: bronchoalveolar lavage; C_dyn: dynamic compliance; BM: bone marrow; HDM: house dust mite; HFD: high-fat diet; ILC2s: type 2 innate lymphocyte cells; ROS: reactive oxygen species; R_L: lung resistance; TSLP: thymic stromal lymphopoietin; TCC: total cell count; WT: wild type.

TSLP up-regulates inflammatory responses through induction of autophagy in T cells

Thymic stromal lymphopoietin (TSLP), a type I cytokine belonging to the IL-2 cytokine family, promotes Th2-mediated inflammatory responses. The aim of this study is to investigate whether TSLP increases inflammatory responses via induction of autophagy using a murine T cell lymphoma cell line, EL4 cells, and lipopolysaccharide (LPS)-injected mice. TSLP increased expression levels of autophagy-related factors, such as Beclin-1, LC3-II, p62, Atg5, and lysosome associated membrane protein 1/2, whereas these factors increased by TSLP disappeared by neutralization of TSLP in EL4 cells. TSLP activated JAK1/JAK2/STAT5/JNK/PI3K, while the blockade of JAK1/JAK2/STAT5/JNK/PI3K signaling pathways reduced the expression levels of Beclin-1, LC3-II, and p62 in TSLP-stimulated EL4 cells. In addition, TSLP simultaneously increased levels of inflammatory cytokines via induction of autophagy by activation of JAK1/JAK2/STAT5/JNK/PI3K signaling pathways. In an LPS-induced acute liver injury (ALI) mouse model, exogenous TSLP increased expression levels of Beclin-1 and LC3-II, whereas functional deficiency of TSLP by TSLP siRNA resulted in lower expression of Beclin-1, LC3-II, and inflammatory cytokines, impairing their ability to form autophagosomes in ALI mice. Thus, our findings show a new role of TSLP between autophagy and inflammatory responses. In conclusion, regulating TSLP-induced autophagy may be a potential therapeutic strategy for inflammatory responses.

Thymic stromal lymphopoietin and alarmins as possible therapeutical targets for asthma

PURPOSE OF REVIEW

Overview of epithelial cytokines, particularly thymic stromal lymphopoietin (TSLP), released by the airway epithelium and the effects of their inhibition on the outcomes of patients with asthma.

RECENT FINDINGS

The epithelial cytokines are early mediators at the top of the inflammatory cascade and are attractive therapeutic targets to prevent exacerbations and improve lung function in patients with type 2 and nontype 2 asthma.

SUMMARY

Clinical trials demonstrated that tezepelumab, an anti-TSLP monoclonal antibody, is a promising alternative treatment for asthma that is effective also in nontype 2 asthma. The PATHWAY and NAVIGATOR trials have assessed its effects in improving outcomes on broad clinically diverse populations. The identification of biomarkers will help to predict potential responders and help in asthma treatment personalization.

Functional characterisation of two receptor interaction determinants in human thymic stromal lymphopoietin

Thymic stromal lymphopoietin (TSLP) is a pro-inflammatory cytokine with important pathological roles in Asthma bronchiale, malignant tumours and other diseases. The heterodimeric human TSLP receptor (hTSLPR) consists of the TSLP-binding subunit (TSLPRα) and the IL-7Rα-subunit. We studied the properties of hTSLP variants with mutations in their bipartite interaction interface towards IL-7Rα. One mutant (T46D/K101D) showed only mild impairment in receptor affinity but a massive reduction in biological activity. To facilitate the future development of hTSLP mutants with drug properties, we have devised a eukaryontic cytokine display assay with activity read-out and intrinsic genotype-phenotype coupling.

Interactions of thymic stromal lymphopoietin with interleukin-4 in adaptive immunity during Aspergillus fumigatus keratitis

AIM

To investigate the potential interactions of thymic stromal lymphopoietin (TSLP) with interleukin-4 (IL-4) in adaptive immunity during fungal keratitis (FK).

METHODS

An FK mouse model was induced with Aspergillus fumigatus (AF) hyphal infection. Mice were divided into several groups: untreated, phosphate buffer saline (PBS), infected with AF, and pretreated with a scrambled siRNA, a TSLP-specific siRNA (TSLP siRNA), murine recombinant TSLP (rTSLP), immunoglobulin G (IgG), murine recombinant IFN (rIFN-γ), murine recombinant IL-4 (rIL-4), rIL-13, murine recombinant IL-17A (rIL-17A), and murine recombinant IL-17F (rIL-17F) groups. Quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) or Western blot were performed to determine mRNA and protein levels in the inflamed cornea. Cytokine locations were observed by immunofluoresence staining after AF hyphal infection.

RESULTS

Compared to those in the untreated group, TSLP and T helper type 1 (Th1) cytokine levels in the AF group were upregulated at 24h post infection (hpi), and those of T helper type 2 (Th2) and T helper type 17 (Th17) cytokines were increased at 5d post infection (dpi). Th2 cytokine levels were decreased in the TSLP siRNA-pretreated group and increased in the rTSLP-pretreated group compared with the AF group. The TSLP level was increased in the rIL-4-pretreated group, but there were no significant changes among the other groups. Immunofluorescence staining showed cytokine locations after AF hyphal infection.

CONCLUSION

TSLP induces a Th2 immune response and promots Th2 T cell differentiation in vivo. IL-4 promotes TSLP secretion. Therefore, TSLP with IL-4 regulates adaptive immunity in FK.

[Search for Compounds Regulating TSLP Production]

Thymic stromal lymphopoietin (TSLP) is an epithelial cell-derived immunostimulatory factor, which activates several immune cells such as dendritic cells, T cells, and mast cells. Recently, epithelial cell-derived TSLP has gained immense attention as a cytokine that induces allergic immune responses. Therefore, understanding the regulation of TSLP production is an important step in uncovering the pathophysiology of allergic diseases. Moreover, the compounds that regulate TSLP production can be used as therapeutic drugs for the treatment of allergic diseases. We aim to elucidate the detailed regulation of TSLP production from epithelial cells, and in doing so discovered new regulating factors and an inhibitor of TSLP production. This review article explains the role of TSLP in allergic diseases, its regulation, and our research results.

Human Lung-Resident Macrophages Express and Are Targets of Thymic Stromal Lymphopoietin in the Tumor Microenvironment

Thymic stromal lymphopoietin (TSLP) is a pleiotropic cytokine highly expressed by epithelial cells and several innate and adaptive immune cells. TSLP exerts its biological effects by binding to a heterodimeric complex composed of TSLP receptor (TSLPR) and IL-7Rα. In humans, there are two TSLP isoforms: the short form (sfTSLP), constitutively expressed, and the long form (lfTSLP), which is upregulated in inflammation. TSLP has been implicated in the induction and progression of several experimental and human cancers. Primary human lung macrophages (HLMs), monocyte-derived macrophages (MDMs), and peripheral blood monocytes consitutively expressed sfTSLP mRNA. Incubation of HLMs, MDMs, and monocytes with lipopolysaccharide (LPS) or IL-4, but not with IL-13, induced TSLP release from HLMs. LPS, but not IL-4 or IL-13, induced CXCL8 release from HLMs. LPS, IL-4 alone or in combination with IL-13, induced the expression of lfTSLP, but not of sfTSLP from HLMs. Preincubation of HLMs with IL-4, alone or in combination with IL-13, but not IL-13 alone, synergistically enhanced TSLP release from LPS-activated macrophages. By contrast, IL-4, alone or in combination with IL-13, inhibited LPS-induced CXCL8 release from HLMs. Immunoreactive TSLP was detected in lysates of HLMs, MDMs, and monocytes. Incubation of HLMs with TSLP induced the release of proinflammatory (TNF-α), angiogenic (VEGF-A, angiopoietin 2), and lymphangiogenic (VEGF-C) factors. TSLP, TSLPR, and IL-7Rα were expressed in intratumoral and peritumoral areas of human lung cancer. sfTSLP and lfTSLP mRNAs were differentially expressed in peritumoral and intratumoral lung cancer tissues. The TSLP system, expressed in HLMs, MDMs, and monocytes, could play a role in chronic inflammatory disorders including lung cancer.

Genotype Associations with the Different Phenotypes of Atopic Dermatitis in Children

This study deals with detecting the associations of atopic dermatitis' (AD) phenotypes in children: alone or combined with seasonal allergic rhino-conjunctivitis (SARC) and/or perennial allergic rhinitis (PAR), and/or with bronchial asthma (BA) with single nucleotide polymorphisms (SNP) of filaggrin (FLG), thymic stromal lymphopoietin (TSLP) and orsomucoid-like-1 protein 3 (ORMDL3) genes. Male and female pediatric patients aged from 3 to 18 years old were recruited into the main (AD in different combinations with SARC, PAR, BA) and control groups (disorders of digestives system, neither clinical nor laboratory signs of atopy). Patients were genotyped for SNP of rs_7927894 FLG, rs_11466749 TSLP, rs_7216389 ORMDL3 variants. Statistically significant associations of the increased risk were detected of AD combined with SARC and/or PAR and AD combined with BA (possibly, SARC and/or PAR) with C/T rs_7927894 FLG and T/T rs_7216389 ORMDL3 genotypes. Genotype C/C rs_7927894 FLG significantly decreases the risk of AD combined with SARC and/or PAR by 2.56 fold. Several genotypes' associations had a trend to significance: C/C rs_7216389 ORMDL3 decreases and C/T rs_7216389 ORMDL3 increases the risk for developing AD alone phenotype; A/G rs_11466749 TSLP decreases the risk of AD combined with BA (possibly, SARC and/or PAR) phenotype development.

Molecular Targets for Biological Therapies of Severe Asthma: Focus on Benralizumab and Tezepelumab

Asthma is a heterogeneous respiratory disease characterized by usually reversible bronchial obstruction, which is clinically expressed by different phenotypes driven by complex pathobiological mechanisms (endotypes). In recent years several molecular effectors and signaling pathways have emerged as suitable targets for biological therapies of severe asthma, refractory to standard treatments. Indeed, various therapeutic mono-clonal antibodies currently allow one to intercept at different levels the chain of pathogenic events leading to type 2 (T2) airway inflammation. Pro-allergic immunoglobulin E (IgE) is the first molecule against which an anti-asthma monoclonal antibody (omalizumab) was developed; today other targets are successfully being exploited by biological treatments for severe asthma. In particular, pro-eosinophilic interleukin 5 (IL-5) can be targeted by mepolizumab or reslizumab, whereas benralizumab is a selective blocker of IL-5 receptor, and IL-4 and IL-13 can be targeted by dupilumab. Besides these drugs, which are already available in medical practice, other biologics are under clinical development such as those targeting innate cytokines, including the alarmin thymic stromal lymphopoietin (TSLP), which plays a key role in the pathogenesis of type 2 asthma. Therefore, ongoing and future biological therapies are significantly changing severe asthma management on a global level. These new therapeutic options make it possible to implement phenotype/endotype-specific treatments, which are delineating personalized approaches precisely addressing the individual traits of asthma pathobiology. The aim of the study is to review the immunopathology and treatment efficacy for severe asthma and focused on new biological agents with benralizumab (anti-IL-5) and tezepelumab (anti-TSLP).

Vitamin D3-elicited CD14+ human skin dendritic cells promote thymic stromal lymphopoietin-independent type 2 T-helper responses

BACKGROUND

Immune modulation by vitamin D3 through dendritic cells (DCs) remains controversial. Human DCs exposed in vitro counteract type-1 T-helper (Th1) differentiation and induce regulatory T cells. However, cutaneous application on mice promotes Th2-driven inflammation resembling atopic dermatitis and relying on thymic stromal lymphopoietin (TSLP) from keratinocytes and T-cell orientation by TSLP-stimulated skin DCs. We studied the effects of vitamin D3 in human skin, focusing on TSLP production and the role of skin DCs in T-cell differentiation.

METHODS

Human healthy skin explants were exposed in vitro to vitamin D3 analogs. Migrating DCs were analyzed and TSLP quantified in the supernatant. Allogeneic naïve CD4+ T cells were cocultured with DCs to assess their proliferation and cytokine production.

RESULTS

Vitamin D3 induced skin DCs to differentiate Th2 cells producing IL-4 and IL-13. Vitamin D3 triggered TSLP release in ~30% of skin explants, correlating with IL-13 detection in Th2 cells. In these donors, blocking TSLP receptor during skin explant cultures abrogated IL-13 production, yet IL-4+ Th2 cells were unaffected. Among skin DCs emerged CD14+ cells that had responded directly to vitamin D3 and differed from classical CD14+ dermal emigrants. Vitamin D3-elicited CD14+ DCs sufficed to promote IL-4+ Th2 cells in a TSLP-independent manner.

CONCLUSION

Vitamin D3, despite inducing TSLP in some donors, had a direct influence on skin DCs, affecting their phenotype and ability to drive Th2 responses independently of TSLP. Our findings pave the way toward in vitro systems that accurately model human cutaneous Th2 responses, notably involved in atopic dermatitis.

Th2 Modulation of Transient Receptor Potential Channels: An Unmet Therapeutic Intervention for Atopic Dermatitis

Atopic dermatitis (AD) is a multifaceted, chronic relapsing inflammatory skin disease that affects people of all ages. It is characterized by chronic eczema, constant pruritus, and severe discomfort. AD often progresses from mild annoyance to intractable pruritic inflammatory lesions associated with exacerbated skin sensitivity. The T helper-2 (Th2) response is mainly linked to the acute and subacute phase, whereas Th1 response has been associated in addition with the chronic phase. IL-17, IL-22, TSLP, and IL-31 also play a role in AD. Transient receptor potential (TRP) cation channels play a significant role in neuroinflammation, itch and pain, indicating neuroimmune circuits in AD. However, the Th2-driven cutaneous sensitization of TRP channels is underappreciated. Emerging findings suggest that critical Th2-related cytokines cause potentiation of TRP channels, thereby exaggerating inflammation and itch sensation. Evidence involves the following: (i) IL-13 enhances TRPV1 and TRPA1 transcription levels; (ii) IL-31 sensitizes TRPV1 via transcriptional and channel modulation, and indirectly modulates TRPV3 in keratinocytes; (iii) The Th2-cytokine TSLP increases TRPA1 synthesis in sensory neurons. These changes could be further enhanced by other Th2 cytokines, including IL-4, IL-25, and IL-33, which are inducers for IL-13, IL-31, or TSLP in skin. Taken together, this review highlights that Th2 cytokines potentiate TRP channels through diverse mechanisms under different inflammatory and pruritic conditions, and link this effect to distinct signaling cascades in AD. This review strengthens the notion that interrupting Th2-driven modulation of TRP channels will inhibit transition from acute to chronic AD, thereby aiding the development of effective therapeutics and treatment optimization.

Thymic Stromal Lymphopoietin in Cutaneous Immune-Mediated Diseases

Thymic stromal lymphopoietin (TSLP) was initially demonstrated to be critical in regulating inflammatory responses among various allergic disorders (such as atopic dermatitis, food allergy, and asthma). Although two isoforms (short form and long form) of TSLP have been demonstrated in human tissues, the long form of TSLP (lfTSLP) is strongly implicated in the pathogenesis of allergies and cutaneous immune-mediated diseases. The immunomodulatory activity of lfTSLP varies widely, driving T helper (Th) cells polarizing Th2 and Th17 immune responses and inducing itch. Moreover, lfTSLP is closely associated with skin fibrosis, epidermal hyperplasia, angiogenesis, and homeostatic tolerogenic regulations. This review highlights significant progress from experimental and clinical studies on lfTSLP in cutaneous immune-mediated diseases (atopic dermatitis, psoriasis, bullous pemphigoid, systemic sclerosis, chronic spontaneous urticaria, Behçet’s disease, vitiligo, rosacea, systemic lupus erythematosus, and alopecia areata). We also offer original insights into the pleiotropic properties of the cytokine TSLP in various pathophysiological conditions, with significant clinical implications of TSLP-targeted therapies for immune-mediated skin diseases in the future.

Topical application of an amygdalin analogue reduces inflammation and keratinocyte proliferation in a psoriasis mouse model

Psoriasis is a chronic inflammatory skin disease without cure. Systemic and biological therapies are the most effective treatments for patients with severe psoriasis. However, these drugs can cause serious side effects from extended use. Safe and effective topical drugs are needed to decrease psoriatic plaques and reduce the risk of adverse effects. Amygdalin analogues are stable small molecules that showed benefits in psoriasis xenografts to immune‐deficient mice by systemic application. However, whether topical application of these amygdalin analogues could reduce the progression of the psoriatic phenotype in an immune‐competent organism is unknown. Here, we analyse the efficiency of topical application of an amygdalin analogue cream on a well‐established genetic and immune‐competent mouse model of psoriasis. Topical application of an amygdalin analogue cream ameliorates psoriasis‐like disease in mice, reduces epidermal hyperplasia and skin inflammation. Amygdalin analogue treatment leads to reduced expression of local pro‐inflammatory cytokines, but systemic pro‐inflammatory cytokines that are highly expressed in psoriasis patients such as IL‐17A, IL6 or G‐CSF are also decreased. Furthermore, expression of important mediators of psoriasis initiation and epidermal hyperplasia, such as TNFa, S100A9 and TSLP, is decreased in lesional epidermis after amygdalin analogue treatment. In conclusion, we show that amygdalin analogue reduces the proliferative capacity of psoriasis‐like stimulated keratinocytes and their inflammatory response in vivo and in vitro. These results suggest that topical application of amygdalin analogues may represent a safe and effective treatment for psoriasis.

A murine model of eosinophilic chronic rhinosinusitis using the topical application of a vitamin D3 analog

BACKGROUND

Eosinophilic chronic rhinosinusitis (ECRS) is a chronic inflammatory disease, characterized by eosinophilic infiltration, T-helper type 2 (Th2-type) response, and olfactory dysfunction. A master regulator of Th2-type inflammation, thymic stromal lymphopoietin (TSLP), is important for basophil activation. TSLP-elicited basophils are a key factor in the pathogenesis of ECRS.

METHODS

In order to elucidate the mechanisms of ECRS in humans, we aimed to establish a murine model of ECRS based on TSLP production in response to the topical application of MC903 (a vitamin D3 analog) and the subsequent TSLP-induced basophil activation. Histological analyses were performed to assess immune cell infiltration into the nasal mucosa and to explore the impact of eosinophilic inflammation on the olfactory epithelium. The status of Th2-type inflammation was evaluated by quantitative real-time PCR and enzyme-linked immunosorbent assay (ELISA).

RESULTS

Eosinophils, basophils, and M2 macrophages increased significantly in the nasal mucosa of the mice treated with MC903 and ovalbumin (OVA), compared to those treated with OVA alone or the controls. Quantitative real-time PCR and ELISA revealed elevated expression of interleukin (IL)-4, IL-5, IL-13, TSLP, the chemokine CCL11, and CCL24 in the nasal mucosa of the ECRS mice. In parallel, thinned olfactory epithelium and decreased mature olfactory sensory neurons were observed in the ECRS mice.

CONCLUSIONS

Our model of ECRS displayed Th2-type inflammation in the sinonasal region, including both eosinophil infiltration and basophil infiltration. Additionally, olfactory epithelium turned out to be affected by eosinophilic inflammation. These features are consistent with the characteristics of the human ECRS.

Chrysin Inhibits TNFα-Induced TSLP Expression through Downregulation of EGR1 Expression in Keratinocytes

Thymic stromal lymphopoietin (TSLP) is an epithelial cell-derived cytokine that acts as a critical mediator in the pathogenesis of atopic dermatitis (AD). Various therapeutic agents that prevent TSLP function can efficiently relieve the clinical symptoms of AD. However, the downregulation of TSLP expression by therapeutic agents remains poorly understood. In this study, we investigated the mode of action of chrysin in TSLP suppression in an AD-like inflammatory environment. We observed that the transcription factor early growth response (EGR1) contributed to the tumor necrosis factor alpha (TNFα)-induced transcription of TSLP. Chrysin attenuated TNFα-induced TSLP expression by downregulating EGR1 expression in HaCaT keratinocytes. We also showed that the oral administration of chrysin improved AD-like skin lesions in the ear and neck of BALB/c mice challenged with 2,4-dinitrochlorobenzene. We also showed that chrysin suppressed the expression of EGR1 and TSLP by inhibiting the extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK) 1/2 mitogen-activated protein kinase pathways. Collectively, the findings of this study suggest that chrysin improves AD-like skin lesions, at least in part, through the downregulation of the ERK1/2 or JNK1/2-EGR1-TSLP signaling axis in keratinocytes.

Potential Targets to Mitigate Trauma- or Sepsis-Induced Immune Suppression

In sepsis and trauma, pathogens and injured tissue provoke a systemic inflammatory reaction which can lead to overwhelming inflammation. Concurrent with the innate hyperinflammatory response is adaptive immune suppression that can become chronic. A current key issue today is that patients who undergo intensive medical care after sepsis or trauma have a high mortality rate after being discharged. This high mortality is thought to be associated with persistent immunosuppression. Knowledge about the pathophysiology leading to this state remains fragmented. Immunosuppressive cytokines play an essential role in mediating and upholding immunosuppression in these patients. Specifically, the cytokines Interleukin-10 (IL-10), Transforming Growth Factor-β (TGF-β) and Thymic stromal lymphopoietin (TSLP) are reported to have potent immunosuppressive capacities. Here, we review their ability to suppress inflammation, their dynamics in sepsis and trauma and what drives the pathologic release of these cytokines. They do exert paradoxical effects under certain conditions, which makes it necessary to evaluate their functions in the context of dynamic changes post-sepsis and trauma. Several drugs modulating their functions are currently in clinical trials in the treatment of other pathologies. We provide an overview of the current literature on the effects of IL-10, TGF-β and TSLP in sepsis and trauma and suggest therapeutic approaches for their modulation.

Efficacy of Tezepelumab in Patients with Severe, Uncontrolled Asthma with and without Nasal Polyposis: A Post Hoc Analysis of the Phase 2b PATHWAY Study

Background

Tezepelumab is a human monoclonal antibody that blocks thymic stromal lymphopoietin, an epithelial cytokine implicated in asthma pathogenesis, from binding to its heterodimeric receptor. In the phase 2b PATHWAY study, tezepelumab significantly reduced annualized asthma exacerbation rates (AAERs) versus placebo, irrespective of baseline disease characteristics, and improved lung function and symptom control, in adults with severe, uncontrolled asthma. This post hoc analysis assessed the efficacy of tezepelumab in adults with severe, uncontrolled asthma with and without nasal polyposis (NP).

Methods

In this post hoc analysis of the PATHWAY study (NCT02054130), participants (N=550) were randomized 1:1:1:1 to receive subcutaneous tezepelumab 70 mg every 4 weeks (Q4W), 210 mg Q4W or 280 mg every 2 weeks (Q2W), or placebo Q2W, for 52 weeks. The AAER over 52 weeks and the change from baseline to week 52 in blood eosinophil count, fractional exhaled nitric oxide (FeNO) levels and serum levels of interleukin (IL)-5 and IL-13 with tezepelumab 210 mg (the phase 3 dose) and placebo were analyzed in patients grouped by self-reported presence (NP+) or absence (NP-) of NP at screening.

Results

At baseline, NP+ patients had higher blood eosinophil counts, higher FeNO levels and higher serum IL-5 and IL-13 levels than NP- patients. Tezepelumab 210 mg reduced the AAER versus placebo to a similar extent in both NP+ and NP- patients (NP+, 75% [95% confidence interval (CI): 15, 93], n=23; NP-, 73% [95% CI: 47, 86], n=112). Patients treated with tezepelumab 210 mg demonstrated greater reductions in blood eosinophil count and levels of FeNO, IL-5 and IL-13 than placebo-treated patients, irrespective of NP status.

Discussion

Tezepelumab reduced exacerbations and reduced type 2 inflammatory biomarkers in patients with and those without NP, supporting its efficacy in a broad population of patients with severe asthma.

Skin-resident natural killer T cells participate in cutaneous allergic inflammation in atopic dermatitis

BACKGROUND

Natural killer T (NKT) cells are unconventional T cells that bridge innate and adaptive immunity. NKT cells have been implicated in the development of atopic dermatitis (AD).

OBJECTIVE

We aimed to investigate the role of NKT cells in AD development, especially in skin.

METHODS

Global proteomic and transcriptomic analyses were performed by using skin and blood from human healthy-controls and patients with AD. Levels of CXCR4 and CXCL12 expression in skin NKT cells were analyzed in human AD and mouse AD models. By using parabiosis and intravital imaging, the role of skin CXCR4⁺ NKT cells was further evaluated in models of mice with AD by using CXCR4-conditionally deficient or CXCL12 transgenic mice.

RESULTS

CXCR4 and its cognate ligand CXCL12 were significantly upregulated in the skin of humans with AD by global transcriptomic and proteomic analyses. CXCR4⁺ NKT cells were enriched in AD skin, and their levels were consistently elevated in our models of mice with AD. Allergen-induced NKT cells participate in cutaneous allergic inflammation. Similar to tissue-resident memory T cells, the predominant skin NKT cells were CXCR4⁺ and CD69⁺. Skin-resident NKT cells uniquely expressed CXCR4, unlike NKT cells in the liver, spleen, and lymph nodes. Skin fibroblasts were the main source of CXCL12. CXCR4⁺ NKT cells preferentially trafficked to CXCL12-rich areas, forming an enriched CXCR4⁺ tissue-resident NKT cells/CXCL12⁺ cell cluster that developed in acute and chronic allergic inflammation in our models of mice with AD.

CONCLUSIONS

CXCR4⁺ tissue-resident NKT cells may form a niche that contributes to AD, in which CXCL12 is highly expressed.

Tezepelumab Reduces Exacerbations Across All Seasons in Patients with Severe, Uncontrolled Asthma: A Post Hoc Analysis of the PATHWAY Phase 2b Study

Introduction

Tezepelumab is a human monoclonal antibody that blocks thymic stromal lymphopoietin (TSLP), an epithelial cytokine implicated in airway inflammation in asthma, from binding to its heterodimeric receptor. In the PATHWAY phase 2b study, tezepelumab significantly reduced exacerbation rates compared with placebo in adults with severe, uncontrolled asthma, irrespective of baseline disease characteristics.

Objective

To evaluate the effect of tezepelumab on asthma exacerbations on a seasonal basis.

Methods

This was a post hoc analysis of the PATHWAY study (NCT02054130). Adults (N=550) with severe, uncontrolled asthma were randomized 1:1:1:1 to receive subcutaneous tezepelumab 70 mg every 4 weeks (Q4W), 210 mg Q4W or 280 mg every 2 weeks (Q2W), or placebo Q2W, for 52 weeks. The annualized asthma exacerbation rate (AAER), total number of days with an exacerbation, proportion of patients with at least one exacerbation or 0, 1 or ≥2 exacerbations, and proportion of patients experiencing an exacerbation per day were evaluated by season and over the year, by treatment in the overall study population and in subgroups according to baseline blood eosinophil count (≥300 cells/µL or <300 cells/µL) or atopic asthma status (fluoro-enzyme immunoassay [FEIA]+ or FEIA-).

Results

Seasonal variations in exacerbation rates were found, with peaks observed in fall and winter, and greater variations in patients with high blood eosinophil counts (≥300 cells/µL). Tezepelumab treatment consistently reduced exacerbation rates across all seasons compared with placebo. Furthermore, there was a trend, which was not significant, toward a reduction in the total number of days with exacerbations and in the proportion of patients with exacerbations during each season in patients treated with tezepelumab compared with those who received placebo, irrespective of blood eosinophil count or atopic asthma status.

Conclusion

Tezepelumab reduced exacerbations across all seasons, irrespective of evaluated baseline disease characteristics. These data support the efficacy of tezepelumab in a broad population of patients with severe, uncontrolled asthma.

Effects of Resveratrol on Thymic Stromal Lymphopoietin Expression in Mast Cells

Background and objectives: Cytokine thymic stromal lymphopoietin (TSLP) plays a pivotal role in the pathogenesis of atopic diseases such as atopic dermatitis, allergic rhinitis, and asthma. Resveratrol (RSV) exerts various pharmacological effects such as antioxidant, anti-inflammatory, neuroprotective, and anticancer. Although, it has been verified the beneficial effects of RSV on various subjects, the effect of RSV on thymic stromal lymphopoietin (TSLP) regulation has not been elucidated. Materials and Methods: Here, we examined how RSV regulates TSLP in HMC-1 cells. Enzyme-linked immunosorbent assay, real-time polymerase chain reaction, Western blotting, and calcium assay were performed to evaluate the effect of RSV. Results: TSLP production and mRNA expression were reduced by RSV. RSV down-regulated nuclear factor-κB activation, IκBα phosphorylation as well as activation of receptor-interacting protein2 and caspase-1 in HMC-1 cells. In addition, RSV treatment decreased the up-regulation of intracellular calcium in HMC-1 cells. Conclusions: These results suggest that RSV might be useful for the treatment of atopic diseases through blocking of TSLP.

Tezepelumab Pharmacokinetics, Safety, and Tolerability After Administration via Vial-and-syringe, Accessorized Prefilled Syringe, or Autoinjector: A Randomized Trial in Healthy Volunteers

PURPOSE

Tezepelumab is an anti-thymic stromal lymphopoietin monoclonal antibody therapeutic in development for patients with severe, uncontrolled asthma. In ongoing Phase III studies, tezepelumab is administered via subcutaneous (SC) injections using a vial-and-syringe (V-S). This study compared the pharmacokinetic (PK) parameters, safety, and tolerability of tezepelumab administered subcutaneously via V-S versus via an accessorized prefilled syringe (APFS) or autoinjector (AI).

METHODS

This single-center, randomized, open-label, parallel-group study was conducted in healthy volunteers aged 18-65 years. Participants, stratified according to weight (50 to <70 kg, 70 to <80 kg, or 80-90 kg), were randomized evenly to 9 groups representing injections to the abdomen, thigh, or upper arm via V-S, APFS, or AI. Tezepelumab PK parameters over 113 days were evaluated after a single 210-mg SC dose. The primary end points were comparison of C_max and AUC_0-∞ between device groups. Further PK parameters, immunogenicity, safety (including injection site reactions [ISRs] and injection site pain [visual analog scale]) were also assessed.

FINDINGS

A total of 315 adults were randomized to treatment. Geometric mean ratios for comparisons between device groups of C_max, AUC_0-∞, and AUC_0-last were close to 1, with 90% CIs all within the range of 0.8-1.25, meeting bioequivalence criteria. PK variables were also similar between devices across injection sites and weight categories. Across devices, thigh injection resulted in slightly higher exposure than upper arm injection, and abdomen injection resulted in exposure similar to or slightly lower than thigh injection; however, these differences were not clinically meaningful. Treatment-emergent anti-tezepelumab antibodies were present in 3 (2.9%), 1 (1.0%), and 0 participants in the V-S, APFS, and AI groups, respectively. Treatment-related adverse events were reported in 15.0% of participants overall (V-S, 10.7%; APFS, 18.1%; AI, 16.0%), including ISRs in 1 (1.0%), 3 (2.9%), and 3 (2.8%) participants in the V-S, APFS, and AI groups. Median visual analog scale pain score (0-100 mm scale) was 2 mm immediately after injection and was 0 mm at 30 min for all groups.

IMPLICATIONS

Tezepelumab PK parameters after a single 210-mg SC dose were comparable when administered via V-S, APFS, or AI. In all groups, immunogenicity rate and injection site pain were low, and ISRs were uncommon. These findings support administration of tezepelumab via APFS or AI, in addition to V-S, providing patients and physicians with greater choice and the potential convenience of at-home use. ClinicalTrials.gov identifier: NCT03989544.