Thymic Stromal Lymphopoietin Secretion Research Articles

The roles of epidermal Blimp-1 in atopic dermatitis

Abstract Keratinocytes are the main cell type constructing the epidermis of animals, which can further differentiate into corneocytes and express multiple innate immune receptors. B lymphocyte-induced maturation protein-1 (Blimp-1) plays a crucial rule in directing cornification of keratinocytes. We previously reported that keratinocyte-specific deletion of Prdm1, the gene encoding Blimp-1, induced spontaneous inflammation in the skin of adult mice. We further found that deletion of Prdm1in keratinocytes in Balb/c genetic background caused hyper-production of type 2 cytokines and thymic stromal lymphopoietin (TSLP) in the skin, and staphylococci colonization, which are characteristics of atopic dermatitis (AD). Since K5-CreER+Prdm1f/f(CKO) mice in Balb/c background exhibited AD-like symptoms, we wondered whether they are more susceptible to the disease progression in a murine AD model induced by MC903, a vitamin D3 analog enhancing TSLP production by keratinocytes. We found that CKO mice showed more immune cell infiltration in ear skin, developed more severe epidermal hyperplasia, and induced more TSLP secretion in the skin following topical application of MC903. Recent studies showed that staphylococci colonization activated the transcription of endogenous retroviruses (ERVs) in murine skin, while excess ERV expression led to skin inflammation. As staphylococci colonized on our CKO mouse skin, we hypothesized that enhanced ERV expression may also link to skin inflammation of CKO mice. Indeed, both in vivoand in vitrodeletion of Prdm1in keratinocytes resulted in elevated levels of ERV transcripts. We are studying the contribution of elevated ERV transcripts in Blimp-1-reduction-mediated AD-like skin inflammation.

SARS-CoV-2-Induced TSLP Is Associated with Duration of Hospital Stay in COVID-19 Patients.

Thymic stromal lymphopoietin (TSLP) is an epithelium-derived pro-inflammatory cytokine involved in lung inflammatory responses. Previous studies show conflicting observations in blood TSLP in COVID-19, while none report SARS-CoV-2 inducing TSLP expression in bronchial epithelial cells. Our objective in this study was to determine whether TSLP levels increase in COVID-19 patients and if SARS-CoV-2 induces TSLP expression in bronchial epithelial cells. Plasma cytokine levels were measured in patients hospitalized with confirmed COVID-19 and age- and sex-matched healthy controls. Demographic and clinical information from COVID-19 patients was collected. We determined associations between plasma TSLP and clinical parameters using Poisson regression. Cultured human nasal (HNEpC) and bronchial epithelial cells (NHBEs), Caco-2 cells, and patient-derived bronchial epithelial cells (HBECs) obtained from elective bronchoscopy were infected in vitro with SARS-CoV-2, and secretion as well as intracellular expression of TSLP was detected by immunofluorescence. Increased TSLP levels were detected in the plasma of hospitalized COVID-19 patients (603.4 ± 75.4 vs 997.6 ± 241.4 fg/mL, mean ± SEM), the levels of which correlated with duration of stay in hospital (β: 0.11; 95% confidence interval (CI): 0.01-0.21). In cultured NHBE and HBECs but not HNEpCs or Caco-2 cells, TSLP levels were significantly elevated after 24 h post-infection with SARS-CoV-2 (p < 0.001) in a dose-dependent manner. Plasma TSLP in COVID-19 patients significantly correlated with duration of hospitalization, while SARS-CoV-2 induced TSLP secretion from bronchial epithelial cells in vitro. Based on our findings, TSLP may be considered an important therapeutic target for COVID-19 treatment.

Asthmatic lung fibroblasts promote type 2 immune responses via endoplasmic reticulum stress response dependent thymic stromal lymphopoietin secretion.

Lung fibroblasts contribute to asthma pathology partly through modulation of the immune environment in the airway. Tumor necrosis factor-α (TNFα) expression is upregulated in asthmatic lungs. How asthmatic lung fibroblasts respond to TNFα stimulation and subsequently regulate immune responses is not well understood. Endoplasmic reticulum (ER) stress and unfolded protein responses (UPR) play important roles in asthma, but their functional roles are still under investigation. In this study, we investigated TNFα-induced cytokine production in primary lung fibroblasts from asthmatic vs. non-asthmatic human subjects, and downstream effects on type 2 immune responses. TNFα significantly upregulated IL-6, IL-8, C-C motif chemokine ligand 5 (CCL5), and thymic stromal lymphopoietin (TSLP) mRNA expression and protein secretion by lung fibroblasts. Asthmatic lung fibroblasts secreted higher levels of TSLP which promoted IL-33-induced IL-5 and IL-13 production by peripheral blood mononuclear cells. TNFα exposure enhanced expression of ER stress/UPR pathways in both asthmatic and non-asthmatic lung fibroblasts, especially inositol-requiring protein 1α in asthmatics. ER stress/UPR inhibitors decreased IL-6, CCL5, and TSLP protein secretion by asthmatic lung fibroblasts. Our data suggest that TNFα and lung fibroblasts form an important axis in asthmatic lungs to promote asthmatic inflammation that can be attenuated by inhibiting ER stress/UPR pathway.

Nasal TSLP and periostin in infants with severe bronchiolitis and risk of asthma at 4 years of age

BackgroundSevere bronchiolitis is often associated with subsequent respiratory morbidity, mainly recurrent wheezing and asthma. However, the underlying immune mechanisms remain unclear. The main goal of this study was to investigate the association of nasal detection of periostin and thymic stromal lymphopoietin (TSLP) during severe bronchiolitis with the development of asthma at 4 years of age.MethodsObservational, longitudinal, post-bronchiolitis, hospital-based, follow-up study. Children hospitalized for bronchiolitis between October/2013 and July/2017, currently aged 4 years, included in a previous study to investigate the nasal airway secretion of TSLP and periostin during bronchiolitis, were included. Parents were contacted by telephone, and were invited to a clinical interview based on a structured questionnaire to obtain information on the respiratory evolution. The ISAAC questionnaire for asthma symptoms for 6–7-year-old children, was also employed.ResultsA total of 248 children were included (median age 4.4 years). The mean age at admission for bronchiolitis was 3.1 (IQR: 1.5–6.5) months. Overall, 21% had ever been diagnosed with asthma and 37% had wheezed in the last 12 months. Measurable nasal TSLP was detected at admission in 27(11%) cases and periostin in 157(63%). The detection of nasal TSLP was associated with the subsequent prescription of maintenance asthma treatment (p = 0.04), montelukast (p = 0.01), and the combination montelukast/inhaled glucocorticosteroids (p = 0.03). Admissions for asthma tended to be more frequent in children with TSLP detection (p = 0.07). In the multivariate analysis, adjusting for potential confounders, the detection of TSLP remained independently associated with chronic asthma treatment prescription (aOR:2.724; CI 1.051–7.063, p:0.04) and with current asthma (aOR:3.41; CI 1.20–9.66, p:0.02).Nasal detection of periostin was associated with lower frequency of ever use of short-acting beta2-agonists (SABA) (p = 0.04), lower prevalence of current asthma (p = 0.02), less prescription of maintenance asthma treatment in the past 12 months (p = 0.02, respectively). In the multivariate analysis, periostin was associated with lower risk of asthma at 4 years, independently of the atopic status (aOR:0.511 CI 95% 0.284–0.918, p:0.025).ConclusionsOur results show a positive correlation between nasal TSLP detection in severe bronchiolitis and the presence of current asthma, prescription of asthma maintenance treatment and respiratory admissions up to the age of 4 years. By contrast, we found a protective association between nasal periostin detection and current asthma at 4 years, ever diagnosis of asthma, maintenance asthma treatment prescription, and respiratory admissions.

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.

Epithelial cell alarmin cytokines: Frontline mediators of the asthma inflammatory response.

The exposure of the airway epithelium to external stimuli such as allergens, microbes, and air pollution triggers the release of the alarmin cytokines IL-25, IL-33 and thymic stromal lymphopoietin (TSLP). IL-25, IL-33 and TSLP interact with their ligands, IL-17RA, IL1RL1 and TSLPR respectively, expressed by hematopoietic and non-hematopoietic cells including dendritic cells, ILC2 cells, endothelial cells, and fibroblasts. Alarmins play key roles in driving type 2-high, and to a lesser extent type 2-low responses, in asthma. In addition, studies in which each of these three alarmins were targeted in allergen-challenged mice showed decreased chronicity of type-2 driven disease. Consequently, ascertaining the mechanism of activity of these upstream mediators has implications for understanding the outcome of targeted therapies designed to counteract their activity and alleviate downstream type 2-high and low effector responses. Furthermore, identifying the factors which shift the balance between the elicitation of type 2-high, eosinophilic asthma and type-2 low, neutrophilic-positive/negative asthma by alarmins is essential. In support of these efforts, observations from the NAVIGATOR trial imply that targeting TSLP in patients with tezepelumab results in reduced asthma exacerbations, improved lung function and control of the disease. In this review, we will discuss the mechanisms surrounding the secretion of IL-25, IL-33, and TSLP from the airway epithelium and how this influences the allergic airway cascade. We also review in detail how alarmin-receptor/co-receptor interactions modulate downstream allergic inflammation. Current strategies which target alarmins, their efficacy and inflammatory phenotype will be discussed.

7-Methoxyisoflavone ameliorates atopic dermatitis symptoms by regulating multiple signaling pathways and reducing chemokine production

7-Met, a derivative of soybean isoflavone, is a natural flavonoid compound that has been reported to have multiple signaling pathways regulation effects. This study investigated the therapeutic effects of 7-Met on mice with atopic dermatitis induced by fluorescein isothiocyanate (FITC), or oxazolone (OXZ). 7-Met ameliorated FITC or OXZ-induced atopic dermatitis symptoms by decreasing ear thickness, spleen index, mast cell activation, neutrophil infiltration and serum IgE levels in female BALB/c mice. In FITC-induced atopic dermatitis mice, 7-Met reduced Th1 cytokines production and regulated Th1/Th2 balance by downregulating the secretion of thymic stromal lymphopoietin (TSLP) via inactivation of the NF-κB pathway. In OXZ-induced atopic dermatitis, 7-Met functioned through the reduction of Th17 cytokine production. Our study showed that 7-Methoxyisoflavone alleviated atopic dermatitis by regulating multiple signaling pathways and downregulating chemokine production.

The role of interleukin-33 in the pathogenesis, and treatment of severe asthma

Interleukin-33 (IL-33) belongs to the IL-1 family of cytokines, which has 11 members, including IL-1α, IL-1β, IL-1Ra, IL-18, IL-36α, IL-36β, and IL-37. Unlike its family members, IL-33 mediates T helper type-2 (Th2) immune responses, and promotes eosinophilic inflammation, similar to the other epithelial-derived cytokines, such as IL-25, and thymic stromal lymphopoietin (TSLP). Epithelial injury due to viral, and bacterial infections, allergens, chemical irritants, and trauma lead to secretion of alarmin cytokines, including IL-25, IL-33, and TSLP. IL-33 plays an important role in activating Th2 lymphocytes, group 2 innate lymphoid cells, dendritic cells, mast cells, basophils, and eosinophils, which result in secretion of cytokines, such as IL-4, IL-13, and IL-5; chemokines, including CCL2, and CXCL8, and adhesion molecules. The inflammatory mediators promote eosinophilic airway inflammation, airway hyperresponsiveness, and remodeling. IL-33 signaling is via a complex heterodimeric receptor comprising of IL-1 receptor-like 1 (IL-1RL1), and IL-1 receptor accessory protein. Downstream signaling cascade leads to the transcription of multiple cytokines and chemokines, which orchestrate eosinophilic asthma. Treatment of severe eosinophilic asthma include long-acting beta2-agonists, and inhaled corticosteroids, and addition of biologics at GINA step 4/5, such as omalizumab, mepolizumab, dupilumab, and tezepelumab. Currently, there are no anti-IL-33 biologics which have been approved for the treatment of eosinophilic asthma. Etokimab is a first-in-class IgG1 monoclonal antibody which blocks the activity of IL-33, thereby, inhibiting its biological effects. Phase 2a proof-of-concept clinical trial in 25 patient with severe eosinophilic asthma, showed that a single intravenous dose of etokimab (330 mg) resulted in a rapid and sustained improvement in lung function, and reduction in the asthma control questionnaire-5 scores throughout the study period of 64 days. Recently, itepekimab has been shown to improve asthma control, lung function, and quality of life, although the effects of itepekimab were slightly lesser than those observed for dupilumab. The dual therapy of itepekimab plus dupilumab did not achieve optimal outcomes, moreover, treatment with the doublet resulted in minimal change in pre-bronchodilator FEV1 compared with placebo. Dual blockade of interleukins incriminated in the pathogenesis of eosinophilic asthma need further careful studies, because of the immunological consequences in the era of SARS-CoV-2.

Effect of the combination of theophylline and budesonide on production of proinflammatory cytokines by blood cells of patients with chronic obstructive pulmonary disease

The objective: to evaluate the ability of the combination of theophylline and budesonide to suppress proinflammatory cytokine production byblood cells in patients with chronic obstructive pulmonary disease (COPD).Subjects and Methods. Peripheral blood mononuclear cells (PBMCs) or whole blood cells of COPD patients (n = 27) were incubated with budesonide (10 nM), theophylline (1 μM), or the combination thereof and stimulated with phytohemagglutinin (PHA) or phorbol myristate acetate (PMA) and ionomycin. The enzyme immunoassay was used to evaluate the secretion of thymic stromal lymphopoietin (TSLP), macrophage migration inhibitory factor (MIF), interleukin 17A (IL-17A), IL-33, and other mediators of PBMC cells, and induced PHA. The flow cytometry was used to analyze intracellular production of proinflammatory cytokines stimulated by PMA/ionomycin in T-helpers (CD4+) and cytotoxic T-lymphocytes (CD8+).Results. Theophylline reduced the secretion of IL-4 and IL-17A by PBMC cells. The combination of budesonide with theophylline inhibited the synthesis of IL-4, IL-5, IL-8, IL-13, IL-17A, IL-33, TSLP, MIF by PBMC cells as well as the production of IL-4, IL-8, tumor necrosis factor-α, and interferon-γ by cytotoxic T-lymphocytes and T-helpers. The combination of theophylline and budesonide had a more pronounced inhibitory effect on the production of IL-4 and IL-8 by PBMC cells as well as the synthesis of IL-4 by CD4+ T-cells and IL8 by CD8+ T-lymphocytes versus the effect of monotherapy with budesonide.

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

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

Nortriptyline enhances corticosteroid sensitivity of blood T cells from patients with chronic obstructive pulmonary disease.

Steroid unresponsiveness is a significant problem in the management of chronic obstructive pulmonary disease (COPD). The tricyclic antidepressant nortriptyline has been reported to reverse corticosteroid resistance induced by oxidative stress. This study examined the potential synergistic anti-inflammatory effects of nortriptyline and corticosteroids in T lymphocytes from patients with COPD and the molecular mechanisms underlying their action. Peripheral blood mononuclear cells (PBMCs) or whole blood cells from COPD patients were incubated with budesonide, nortriptyline, or their combinations and stimulated with phytohaemagglutinin (PHA) or phorbol myristate acetate (PMA) plus ionomycin. The release of interleukin 4 (IL-4), IL-5, IL-8 and other mediators from PBMCs was measured by ELISA. Intracellular pro-inflammatory cytokines, glucocorticoid receptor (GR) and its isoform GRβ, histone deacetylase 2 (HDAC2), phosphorylated p38 mitogen-activated protein kinase (p38 MAPK) and p65 nuclear factor-κ (p65 NF-κB) were determined in CD4+ and CD8+ T cells using flow cytometry. Nortriptyline 10 μM decreased PHA-induced release of cytokines: IL-4, IL-5, IL-13, IL-17A, IL-33, macrophage migration inhibitory factor and thymic stromal lymphopoietin (TSLP). This drug alone also reduced the percentage of IL-4, IL-8, interferon gamma (IFNγ) positive CD4+ T cells and IL-4, IL-8 expressing CD8+ T cells stimulated with PMA/ionomycin, whereas nortriptyline 1 μM had less pronounced effect. The combination of budesonide 10 nM with nortriptyline 10 μM was more potent at suppressing IL-4, IL-5, IL-8, IL-13, IL-17A, TSLP secretion from PBMCs, as well as IL-4, IL-8, IFNγ, GRβ expression by CD4+ and CD8+ T cells when compared with single budesonide treatment. The association of budesonide 10 nM and Nt (1 μM to 10 μM) effectively decreased p38 MAPK and p65 NF-κB phosphorylation and increased HDAC2 expression in both CD4+ and CD8+ T cells. In conclusion, nortriptyline alone demonstrates anti-inflammatory effects on blood T lymphocytes from COPD patients. Nortriptyline may also potentiate the effects of glucocorticoids and overcome corticosteroid insensitivity.

Extracellular Mitochondrial Components and Effects on Cardiovascular Disease.

Besides being powerhouses of the cell, mitochondria released into extracellular space act as intercellular signaling. Mitochondria and their components mediate cell-to-cell communication in free form or embedded in a carrier. The pathogenesis of cardiovascular disease is complex, which shows close relationship with inflammation and metabolic abnormalities. Since mitochondria sustain optimal function of the heart, extracellular mitochondria are emerging as a key regulator in the development of cardiovascular disease. In this review, we provide recent findings in the presence and forms of mitochondria transfer between cells, as well as the effects of these mitochondria on vascular inflammation and ischemic myocardium. Mitochondrial transplantation is a novel treatment paradigm for patients suffering from acute cardiovascular accident and challenges the traditional methods of mitochondria isolation.

Glutathionylation chemistry promotes interleukin-1 beta-mediated glycolytic reprogramming and pro-inflammatory signaling in lung epithelial cells.

Glycolysis is a well-known process by which metabolically active cells, such as tumor or immune cells meet their high metabolic demands. Previously, our laboratory has demonstrated that in airway epithelial cells, the pleiotropic cytokine, interleukin-1 beta (IL1B) induces glycolysis and that this contributes to allergic airway inflammation and remodeling. Activation of glycolysis is known to increase NADPH reducing equivalents generated from the pentose phosphate pathway, linking metabolic reprogramming with redox homeostasis. In addition, numerous glycolytic enzymes are known to be redox regulated. However, whether and how redox chemistry regulates metabolic reprogramming more generally remains unclear. In this study, we employed a multi-omics approach in primary mouse airway basal cells to evaluate the role of protein redox biochemistry, specifically protein glutathionylation, in mediating metabolic reprogramming. Our findings demonstrate that IL1B induces glutathionylation of multiple proteins involved in metabolic regulation, notably in the glycolysis pathway. Cells lacking Glutaredoxin-1 (Glrx), the enzyme responsible for reversing glutathionylation, show modulation of multiple metabolic pathways including an enhanced IL1B-induced glycolytic response. This was accompanied by increased secretion of thymic stromal lymphopoietin (TSLP), a cytokine important in asthma pathogenesis. Targeted inhibition of glycolysis prevented TSLP release, confirming the functional relevance of enhanced glycolysis in cells stimulated with IL1B. Collectively, data herein point to an intriguing link between glutathionylation chemistry and glycolytic reprogramming in epithelial cells and suggest that glutathionylation chemistry may represent a therapeutic target in pulmonary pathologies with perturbations in the glycolysis pathway.

3,3'-Diindolylmethane alleviates acute atopic dermatitis by regulating T cell differentiation in a mouse model

Atopic dermatitis is a severe, chronic relapsing inflammatory disease of the skin with family clustering. It is characterized into acute phase, which is dominated by T helper 2-type immune responses, and chronic phase, which is dominated by T helper 1-type immune responses. Studies have shown that 3,3′-diindolylmethane not only has antitumor effects but also can relieve symptoms of inflammatory diseases by inhibiting the nuclear factor-κB signaling pathway and regulating T cell differentiation. To study the effect of 3,3′-diindolylmethane on atopic dermatitis and the underlying mechanism, a mouse model of acute atopic dermatitis was established using 2,4-dinitrofluorobenzene. After intraperitoneal injection of 3,3′-diindolylmethane, skin erythema and edema in mice were significantly alleviated. Furthermore, 3,3′-diindolylmethane reduced immune activation, probably by inhibiting the secretion of thymic stromal lymphopoietin by keratinocytes. 3,3′-Diindolylmethane also promoted the differentiation of regulatory T cells and inhibited the activation of T helper 2 and T helper 17 cells to reduce atopic dermatitis-related immune responses. However, it showed no significant effect on the differentiation of T helper 1 cells. These results indicate that 3,3′-diindolylmethane has a significant inhibitory effect on T helper 2 cells in the acute phase of atopic dermatitis. Our findings may provide not only more insights into the pathological mechanism of AD, but also a new candidate medicine for it.

Regulators of thymic stromal lymphopoietin production by human adipocytes

Thymic stromal lymphopoietin (TSLP) is a cytokine that is known to play a role in inflammatory conditions, especially asthma and atopic dermatitis. It is also recognized to be expressed in human adipose tissue. TSLP production from human adipocytes is stimulated by thyroid-stimulating hormone (TSH). This study aimed to identify TSH-dependent signaling routes that regulate TSLP, to determine if TSLP production is stimulated by other cytokines (IL-1β and TNF-α), and to examine if TSLP production depends on the adipose depot. Human abdominal differentiated adipocytes were stimulated with TSH, IL-1β, or TNF-α. Activation of cell signaling kinases was measured by phospho-immunoblot analysis, and TSLP in medium was assessed by ELISA. TSLP responses from abdominal subcutaneous and omental adipocytes were compared. TSH-stimulated TSLP secretion from subcutaneous adipocytes was enhanced by IBMX (raises cAMP levels) and was blocked by UO126 (inhibitor of MEK1/2-ERK1/2). TSLP secretion was stimulated by IL-1β and by TNF-α. SC-514 (inhibitor of IKKβ/NF-κB) only reduced the former. There was no effect of SB203580 (p38 MAPK inhibitor) or SP600125 (JNK inhibitor) on the stimulation by TSH, IL-1β or TNF-α. Interferon-γ inhibited TSLP responses to TSH, IL-1β, and TNF-α; IL-4 only blocked the response to TNFα. Intra-abdominal omental adipocytes also release TSLP in response to TSH, IL-1β, and TNF-α. We conclude TSLP is produced by human differentiated adipocytes derived from subcutaneous or omental depots in response to a variety of agonists. Further studies will be needed to understand what role it may play in adipose biology.

Inhibition of thymic stromal lymphopoietin production to improve pruritus and quality of life in infants and children with atopic dermatitis

BackgroundAtopic dermatitis (AD) is an inflammatory pruritic chronic dermatosis involving the alarmin thymic stromal lymphopoietin (TSLP), which is directly implicated in AD pruritus.AimsTo evaluate the efficacy of Tambourissa trichophylla leaf extract (TTLE) titrated in polyphenols and 18β‐glycyrrhetinic acid (GA) in vitro and in vivo for AD pruritus.Patients/MethodsInitially, in vitro assessment of TSLP production in keratinocytes was undertaken. In normal human keratinocytes in vitro, TSLP was induced by polyinosinic:polycytidylic acid (Poly:IC), tumor necrosis factor (TNF)‐α, and interleukin (IL)‐4 and then quantified by ELISA in supernatants. Some cells were pretreated with TTLE and/or GA. Thereafter, an in vivo clinical study was performed including 48 infants and children with mild to severe AD flare‐ups, some of which were treated with topical corticosteroids. A topical spray containing TTLE and GA was applied. After 21 days of topical spray application, pruritus, sleeplessness, the SCORing Atopic Dermatitis (SCORAD) index, the Infant's Dermatitis Quality of Life index (IDQOL), and the Dermatitis Family Impact Questionnaire (DFIQ) were assessed.ResultsThymic stromal lymphopoietin secretion was inhibited significantly in an AD environment by TTLE and GA by up to 57.2% and 73.3%, respectively. The use of the topical spray induced a significant reduction in pruritus and sleeplessness scores, as well as the SCORAD, IDQOL, and DFIQ indexes in the total group. Similar results were observed in patient subgroups with or without topical corticosteroid treatment.ConclusionsA topical spray containing TTLE and GA, which inhibit TSLP secretion, efficiently decreases AD pruritus and improves the quality of life of AD patients.

Enhanced Thermal Sensitivity of TRPV3 in Keratinocytes Underlies Heat-Induced Pruritogen Release and Pruritus in Atopic Dermatitis

Itch in atopic dermatitis (AD) is aggravated under warm conditions. Transient receptor potential vanilloid (TRPV) 3, a member of the thermosensitive transient receptor potential channels, is activated by innocuous heat and is abundantly expressed in keratinocytes. The potential role of TRPV3 in itch is illustrated in TRPV3 channelopathies of humans and mice. However, the role of TRPV3 in heat-induced itch in AD and the underlying mechanisms are unclear. Here we showed that keratinocytes isolated from patients with AD exhibit enhanced expression and heat sensitivity with hyperactive channel function of TRPV3. Heat stimulus induced enhanced secretion of thymic stromal lymphopoietin, nerve growth factor, and prostaglandin E2 by keratinocytes from patients with AD through TRPV3 activation. TRPV3 agonists increased thymic stromal lymphopoietin, nerve growth factor, prostaglandin E2, and IL-33 production in human keratinocytes and induced scratching behavior upon intradermal injection in mice. TRPV3 was upregulated in the skin of MC903-induced AD mouse model. Heat stimulation to MC903-treated mice increased scratching behavior and produced higher levels of thymic stromal lymphopoietin, nerve growth factor, prostaglandin E2, and IL-33 from the epidermis, which were attenuated by pharmacologic inhibition of TRPV3. Moreover, neutralization of thymic stromal lymphopoietin reduced heat-evoked scratching in MC903-challenged mice. These results suggest that TRPV3 is a potential therapeutic target for heat-induced itch in AD.

Effects of Honokiol on Activation of Transient Receptor Potential Channel V1 and Secretion of Thymic Stromal Lymphopoietin in HaCaT Keratinocytes

Abstract Objective: This study was performed to investigate the effects of honokiol on the activation of transient receptor potential channel V1 (TRPV1) and the secretion of thymic stromal lymphopoietin (TSLP) in a human benign epidermal keratinocyte line (HaCaT). Methods: HaCaT keratinocytes were cultivated and divided into six groups: capsaicin-induced model control group, capsazepine control group, solvent control group, and three honokiol treatment groups (7.81, 15.63, and 31.25 mg/L of honokiol). The effect of honokiol on calcium (Ca2+) influx was measured by a Ca2+ fluorescence imaging system. The fluorescence intensity (F) of cells was measured. The rate of change in F (ΔF/F 0) was calculated, and the ΔF/F 0–time curve was constructed. HaCaT keratinocytes were stimulated with polyinosinic:polycytidylic acid, recombinant human tumor necrosis factor α, and recombinant human interleukin 4. Different concentrations of honokiol (15.63, 7.81, and 3.91 mg/L) were added to the cells in the respective honokiol groups; 20 mg/L of dexamethasone or 0.5% dimethyl sulfoxide was added to the cells in the positive control group or solvent control group. The TSLP concentration in the HaCaT keratinocytes of each group was detected by enzyme-linked immunosorbent assay. Statistical analysis was performed by one-way analysis of variance and Dunnett t test. Results: The capsazepine-induced Ca2+ fluorescence intensity in HaCaT keratinocytes was significantly inhibited in the 31.25 mg/L honokiol group; ΔF/F 0 at 45 second was 0.76 in the model control group and 0 in the 31.25 mg/L honokiol group. The TSLP level in the 15.63 and 7.81 mg/L honokiol groups was lower than that in the solvent control group (t = 7.382, P = 0.003, and t = 2.766, P = 0.023, respectively), while the TSLP level in the 3.91 mg/L honokiol group was not significantly different from that in the solvent control group (t = 1.872, P = 0.124). Conclusions: Honokiol inhibited the Ca2+ influx induced by capsazepine (TRPV1 agonist) in HaCaT keratinocytes. Honokiol has an inhibitory effect on TSLP secretion in HaCaT keratinocytes.

Subcutaneous injection of recombinant heat shock protein 70 ameliorates atopic dermatitis skin lesions in a mouse model.

Atopic dermatitis (AD) is a chronic inflammatory skin disease and sometimes is a tough challenge for physicians. We previously reported that in Th2 environment, the production and secretion of thymic stromal lymphopoietin (TSLP) from human keratinocytes was inhibited by recombinant heat shock protein 70 (rHSP70). The present study assessed the therapeutic effectiveness of rHSP70 in a mouse model of AD. An experimental model of AD was reproduced by systemic sensitization and local epicutaneous challenge with ovalbumin (OVA). Treatment of rHSP70 was performed by subcutaneous administration. The levels of OVA-specific IgE, as well as cytokines, were detected by ELISA. Skin samples from patch areas were also taken for histologic examination. Injection of rHSP70 improved the histologic picture by reducing the thickness of epidermis and allergic inflammation. Skin sonography revealed rHSP70 ameliorated skin remodeling. rHSP70 also significantly decreased the protein expression of TSLP of skin from patch areas. Furthermore, in ex vivo studies also showed group of rHSP70 treatment decreased IL-13, RANTES, MIP-1β and increased IFN-γ secreted from splenocytes stimulated with OVA. The rHSP70 intervention in the mouse model of AD reduced the skin expression of TSLP and attenuated the clinical appearance of OVA-induced AD mice. The effect was achieved by suppressed Th2 immune response in injected skin tissue and enhanced systemic Th1 immune response. These results suggest that rHSP70 have potential as a promising protein for the treatment of AD.

The Kiwifruit Allergen Act d 1 Activates NF-κB Signaling and Affects mRNA Expression of TJ Proteins and Innate Pro-Allergenic Cytokines.

Impairment of the intestinal barrier is one of the key events in the initiation of the sensitization process in food allergy. The aim of this study was to explore the effects of kiwifruit allergen Act d 1 on intestinal permeability and tight junction protein (TJP) gene expression in vivo and to explore its potential to activate the NF-ĸB signaling pathway and to regulate expression of epithelial pro-allergenic cytokines. Influences of Act d 1 on TJP gene expression and pro-allergenic cytokines in the mouse intestine was analyzed by qPCR upon allergen administration by oral gavage. The effect on the in vivo intestinal permeability was assessed in ELISA by measuring the translocation of β-lactoglobulin (BLG) into circulation. The capacity of Act d 1 to activate the NF-ĸB pathway was tested in HEK293 cells by fluorescent microscopy and flow cytometry. Administration of Actinidin (Act d 1) increased intestinal permeability to the BLG. This was accompanied by changes in gene expression of TJP mRNA and pro-allergenic cytokines IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) compared to the control. Act d 1 reduced TEER of the HEK293 monolayer, was positive in an NF-ĸB-reporter HEK293 cell assay, and induced secretion of TSLP. These findings shed more light on the molecular events in the sensitization process of kiwifruit but possibly also of other protease food allergens.