Thymus and activation-regulated chemokine (TARC)/CCL17 and IgE are associated with elderly asthmatics

Causal effects of pediatric asthma on psychiatric disorders: a bidirectional Mendelian randomization study

BACKGROUND

Previous studies have suggested a potential link between pediatric asthma and psychiatric disorders. However, the causal relationship between pediatric asthma and psychiatric disorders is unclear. Therefore, we used Mendelian randomization to explore causal relationships between pediatric asthma and depression, anxiety disorders, and attention deficit and hyperactivity disorder (ADHD).

METHODS

Genome-wide association studies (GWAS) meta-analyses with the largest possible sample size and independent individuals from European ancestry were selected. The genetic data for depression and anxiety are from FinnGen consortium, while the genetic data for ADHD is from the Psychiatric Genomics Consortium. Inverse variance weighted (IVW) was the main analysis method. The heterogeneity of the instrumental variables (IVs) was assessed using IVW, and the horizontal pleiotropy of the IVs was assessed using MR-Egger.

RESULT

The IVW results showed a significant causal relationship between pediatric asthma and depression (OR = 1.08, 95% CI = 1.02-1.15; p = 0.013). However, there is no evidence to suggest a causal relationship between pediatric asthma, anxiety, and ADHD. Reverse MR suggests a significant causal relationship (OR = 1.27, 95% CI [1.14-1.41], p = 9.64E - 06) between ADHD and pediatric asthma using the IVW method.

CONCLUSIONS

Our findings suggest a causal relationship between pediatric asthma and an increased risk of depression. Additionally, we found that ADHD is significantly associated with a higher risk of pediatric asthma.

C-C motif chemokine ligand 5 contributes to radon exposure-induced lung injury by recruiting dendritic cells to activate effector T helper cells

Radon (222Rn) is a naturally occurring radioactive gas, ionizing radiation emitted by the radon induces oxidative stress and the up-regulation of inflammatory proteins, which may cause lung damage or cancer. However, the underlying pathogenesis remains to be determined. Effector T helper cells are key in mediating the host's protection and immune homeostasis. In this study we revealed that, accompanied by the activation of effector T helper cells, there is a significant increase in C-C motif chemokine ligand 5 (Ccl5) in the lung of mice after cumulative inhalation of radon at 3, 9, 21, 45, 90, and 180 working level months (WLM). In vitro experiments showed that Ccl5 attracts DC migration and promotes the activation of effector T helper cells in the Ccl5-DC and T cells co-culture model. Of particular interest, Ccl5 neutralization in vivo inhibited the migration of DC cells and the subsequent activation of effector T helper cells, which finally protected mice from radon-induced lung damage and inflammatory response. Ultimately, transcriptome sequencing and western blot analysis showed that Ccl5 activates the CCR5/PI3K/AKT/Nr4a1 pathway to increase the secretion of IL-12 and IFN-γ by DC cells, which then promotes the activation of effector T helper cells. Overall, these results indicate that Ccl5 significantly contributes to the progression of radon-induced lung damage by modulating DC to activate effector T helper cells.

Diagnostic value of serum thymus and activation-regulated chemokine (TARC) in fatal asthma

OBJECTIVES

Asthma, a chronic inflammatory airway disease, is characterized by airway hyperresponsiveness and structural changes. Accurate postmortem diagnosis is crucial because of legal and insurance implications, necessitating differentiation from other causes of sudden death. Thymus and activation-regulated chemokine (TARC) is a chemokine that potentially acts as a biomarker of asthma. This study evaluated the diagnostic value of serum TARC combined with immunoglobulin E (IgE) levels as biomarkers in forensic settings.

RESULTS

The subjects were 100 autopsy cases, categorized into fatal asthma (n = 25), acute myocardial infarction (AMI) (n = 37), and traumatic deaths (n = 38). TARC levels were significantly elevated in asthma (525.68 ± 801.87 pg/mL) compared with AMI (180.35 ± 109.37 pg/mL) and trauma (173.26 ± 105.01 pg/mL) cases. Similarly, serum IgE levels were higher in asthma (3363.72 ± 7023.46 KU/L) than in AMI (130.92 ± 260.79 KU/L) and trauma (134.53 ± 195.41 KU/L) cases. ROC curve analysis showed that serum TARC had a sensitivity of 68.0 % and specificity of 73.6 % (AUC 0.763, cut-off value of 225 pg/mL). In comparison, serum IgE had a sensitivity of 80 % and specificity of 86.1 % (AUC 0.881, cut-off value of 307 KU/L). The combined use of TARC and IgE increased the diagnostic specificity to 95.8 %.

CONCLUSIONS

Serum TARC and IgE are valuable biomarkers for diagnosing fatal asthma in forensic settings. While serum TARC levels correlate with Th2-mediated inflammation, the combined measurement of TARC and IgE enhances the diagnostic accuracy, providing significant specificity for confirming asthma diagnosis.

Proteomic signatures of eosinophilic and neutrophilic asthma from serum and sputum

BACKGROUND

Eosinophilic and neutrophilic asthma defined by high levels of blood and sputum eosinophils and neutrophils exemplifies the inflammatory heterogeneity of asthma, particularly severe asthma. We analysed the serum and sputum proteome to identify biomarkers jointly associated with these different phenotypes.

METHODS

Proteomic profiles (N = 1129 proteins) were assayed in sputum (n = 182) and serum (n = 574) from two cohorts (U-BIOPRED and ADEPT) of mild-moderate and severe asthma by SOMAscan. Using least absolute shrinkage and selection operator (LASSO)-penalised logistic regression in a stability selection framework, we sought sparse sets of proteins associated with either eosinophilic or neutrophilic asthma with and without adjustment for established clinical factors including oral corticosteroid use and forced expiratory volume.

FINDINGS

We identified 13 serum proteins associated with eosinophilic asthma, including 7 (PAPP-A, TARC/CCL17, ALT/GPT, IgE, CCL28, CO8A1, and IL5-Rα) that were stably selected while adjusting for clinical factors yielding an AUC of 0.84 (95% CI: 0.83-0.84) compared to 0.62 (95% CI: 0.61-0.63) for clinical factors only. Sputum protein analysis selected only PAPP-A (AUC = 0.81 [95% CI: 0.80-0.81]). 12 serum proteins were associated with neutrophilic asthma, of which 5 (MMP-9, EDAR, GIIE/PLA2G2E, IL-1-R4/IL1RL1, and Elafin) complemented clinical factors increasing the AUC from 0.63 (95% CI: 0.58-0.67) for the model with clinical factors only to 0.89 (95% CI: 0.89-0.90). Our model did not select any sputum proteins associated with neutrophilic status.

INTERPRETATION

Targeted serum proteomic profiles are a non-invasive and scalable approach for subtyping of neutrophilic and eosinophilic asthma and for future functional understanding of these phenotypes.

FUNDING

U-BIOPRED has received funding from the Innovative Medicines Initiative (IMI) Joint Undertaking under grant agreement no. 115010, resources of which are composed of financial contributions from the European Union's Seventh Framework Programme (FP7/2007-2013), and European Federation of Pharmaceutical Industries and Associations (EFPIA) companies' in-kind contributions (www.imi.europa.eu). ADEPT was funded by Johnson & Johnson/Janssen pharmaceutical Company.

The role of inflammation in anxiety and depression in the European U-BIOPRED asthma cohorts

BACKGROUND

Growing evidence indicates high comorbid anxiety and depression in patients with asthma. However, the mechanisms underlying this comorbid condition remain unclear. The aim of this study was to investigate the role of inflammation in comorbid anxiety and depression in three asthma patient cohorts of the Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes (U-BIOPRED) project.

METHODS

U-BIOPRED was conducted by a European Union consortium of 16 academic institutions in 11 European countries. A subset dataset from subjects with valid anxiety and depression measures and a large blood biomarker dataset were analysed, including 198 non-smoking patients with severe asthma (SAn), 65 smoking patients with severe asthma (SAs), 61 non-smoking patients with mild-to-moderate asthma (MMA), and 20 healthy non-smokers (HC). The Hospital Anxiety and Depression Scale was used to measure anxiety and depression and a series of inflammatory markers were analysed by the SomaScan v3 platform (SomaLogic, Boulder, Colo). ANOVA and the Kruskal-Wallis test were used for multiple-group comparisons as appropriate.

RESULTS

There were significant group effects on anxiety and depression among the four cohort groups (p < 0.05). Anxiety and depression of SAn and SAs groups were significantly higher than that of MMA and HC groups (p < 0.05. There were significant differences in serum IL6, MCP1, CCL18, CCL17, IL8, and Eotaxin among the four groups (p < 0.05). Depression was significantly associated with IL6, MCP1, CCL18 level, and CCL17; whereas anxiety was associated with CCL17 only (p < 0.05).

CONCLUSIONS

The current study suggests that severe asthma patients are associated with higher levels of anxiety and depression, and inflammatory responses may underlie this comorbid condition.

Der p 38 Is a Bidirectional Regulator of Eosinophils and Neutrophils in Allergy

The house dust mite is the most common cause of allergic diseases, and TLR4 acts as an overarching receptor for allergic responses. This study aimed to identify novel allergen binding to TLR4 in house dust mites and unveil its unique role in allergic responses. Der p 38 was purified and characterized by liquid chromatography tandem mass spectrometry-based peptide mapping. Biolayer interferometry and structure modeling unveiled TLR4-binding activity and the structure of recombinant Der p 38. The allergenicity of Der p 38 was confirmed by a skin prick test, and basophil activation and dot blot assays. The skin prick test identified 24 out of 45 allergic subjects (53.3%) as Der p 38⁺ subjects. Der p 38-augmented CD203c expression was noted in the basophils of Der p 38⁺ allergic subjects. In animal experiments with wild-type and TLR4 knockout BALB/c mice, Der p 38 administration induced the infiltration of neutrophils as well as eosinophils and exhibited clinical features similar to asthma via TLR4 activation. Persistent Der p 38 administration induced severe neutrophil inflammation. Der p 38 directly suppressed the apoptosis of allergic neutrophils and eosinophils, and enhanced cytokine production in human bronchial epithelial cells, inhibiting neutrophil apoptosis. The mechanisms involved TLR4, LYN, PI3K, AKT, ERK, and NF-κB. These findings may contribute to a deep understanding of Der p 38 as a bridge allergen between eosinophilic and neutrophilic inflammation in the pathogenic mechanisms of allergy.

Der f 38 Is a Novel TLR4-Binding Allergen Related to Allergy Pathogenesis from Dermatophagoides farinae

It is difficult to treat allergic diseases including asthma completely because its pathogenesis remains unclear. House dust mite (HDM) is a critical allergen and Toll-like receptor (TLR) 4 is a member of the toll-like receptor family, which plays an important role in allergic diseases. The purpose of this study was to characterize a novel allergen, Der f 38 binding to TLR4, and unveil its role as an inducer of allergy. Der f 38 expression was detected in the body and feces of Dermatophagoides farinae (DF). Electron microscopy revealed that it was located in the granule layer, the epithelium layer, and microvilli of the posterior midgut. The skin prick test showed that 60% of allergic subjects were Der f 38-positive. Der f 38 enhanced surface 203c expression in basophils of Der f 38-positive allergic subjects. By analysis of the model structure of Der p 38, the expected epitope sites are exposed on the exterior side. In animal experiments, Der f 38 triggered an infiltration of inflammatory cells. Intranasal (IN) administration of Der f 38 increased neutrophils in the lung. Intraperitoneal (IP) and IN injections of Der f 38 induced both eosinophils and neutrophils. Increased total IgE level and histopathological features were found in BALB/c mice treated with Der f 38 by IP and IN injections. TLR4 knockout (KO) BALB/c mice exhibited less inflammation and IgE level in the sera compared to wild type (WT) mice. Der f 38 directly binds to TLR4 using biolayer interferometry. Der f 38 suppressed the apoptosis of neutrophils and eosinophils by downregulating proteins in the proapoptotic pathway including caspase 9, caspase 3, and BAX and upregulating proteins in the anti-apoptotic pathway including BCL-2 and MCL-1. These findings might shed light on the pathogenic mechanisms of allergy to HDM.

The potential role of mesenchymal stem cells in modulating antiageing process

Ageing and age-related diseases share some basic origin that largely converges on inflammation. Precisely, it boils down to a common pathway characterised by the appearance of a fair amount of proinflammatory cytokines known as inflammageing. Among the proposed treatment for antiageing, MSCs gained attention in recent years. Since mesenchymal stem cells (MSCs) can differentiate itself into a myriad of terminal cells, previously it was believed that these cells migrate to the site of injury and perform their therapeutic effect. However, with the more recent discovery of huge amounts of paracrine factors secreted by MSCs, it is now widely accepted that these cells do not engraft upon transplantation but rather unveil their benefits through excretion of bioactive molecules namely those involved in inflammatory and immunomodulatory activities. Conversely, the true function of these paracrine changes has not been thoroughly investigated all these years. Hence, this review will describe in detail on ways MSCs may capitalize its paracrine properties in modulating antiageing process. Through a comprehensive literature search various elements in the antiageing process, we aim to provide a novel treatment perspective of MSCs in antiageing related clinical conditions.

Biology and Clinical Applicability of Plasma Thymus and Activation-Regulated Chemokine (TARC) in Classical Hodgkin Lymphoma

Thymus and activation-regulated chemokine (TARC) is produced by different cell types and is highly expressed in the thymus. It plays an important role in T cell development, trafficking and activation of mature T cells after binding to its receptor C-C chemokine receptor type 4 (CCR4) and consecutive signal transducer and activator of transcription 6 (STAT6) activation. Importantly, TARC is also produced by malignant Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL). In cHL, HRS cells survive and proliferate due to the micro-environment consisting primarily of type 2 T helper (Th2) cells. TARC-mediated signaling initiates a positive feedback loop that is crucial for the interaction between HRS and T cells. The clinical applicability of TARC is diverse. It is useful as diagnostic biomarker in both children and adults with cHL and in other Th2-driven diseases. In adult cHL patients, TARC is also a biomarker for treatment response and prognosis. Finally, blocking TARC signaling and thus inhibiting pathological Th2 cell recruitment could be a therapeutic strategy in cHL. In this review, we summarize the biological functions of TARC and focus on its role in cHL pathogenesis and as a biomarker for cHL and other diseases. We conclude by giving an outlook on putative therapeutic applications of antagonists and inhibitors of TARC-mediated signaling.

Diagnostic value of thymus and activation-regulated chemokine and of periostin in eosinophilic asthma: A prospective study

Background: Serum thymus and activation-regulated chemokine (TARC) and periostin are reliable biomarkers in eosinophilic asthma. Objective: This study was carried out to determine the use of periostin and TARC as biomarkers in asthma and to compare the superiority of one over the other, especially in asthma with an eosinophilic phenotype. Methods: The study was conducted with 87 patients with asthma and 42 healthy control subjects. Patients with asthma were also divided into eosinophilic and non-eosinophilic phenotypes. A pulmonary function test was performed in all the participants, and serum and induced sputum TARC, periostin concentrations, eosinophils, and total immunoglobulin E values were examined. Results: TARC and periostin levels were significantly higher in the asthma group than in the control group (p < 0.001). The serum TARC level in the eosinophilic group was significantly higher than in the non-eosinophilic and control groups (p < 0.001). The induced sputum TARC level was significantly higher in the non-eosinophilic group than in the control group (p < 0.001). The TARC and periostin levels of the patients were evaluated by using receiver operator characteristic analysis. The cutoff value for TARC was determined to be 1415.39 ng/L; likewise, the cutoff value for periostin was 107.60 ng/L. The present study detected that serum levels of TARC correlated to serum levels of periostin (r = 0.54; p = 0.032). Furthermore, when evaluating correlations between serum and sputum levels, there was a correlation detected between TARC and periostin in serum, whereas this correlation was stronger in sputum: r = 0.66, p = 0.020; and r = 0.62, p = 0.028, respectively. Conclusion: Serum and sputum TARC and periostin may contribute for monitoring the improvement of patients, particularly those with asthma. Furthermore, TARC was a more reliable biomarker than periostin for patients with eosinophilic asthma.