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Background: Interleukin (IL)‐33 is an upstream regulator of type 2 (T2) eosinophilic inflammation and has been proposed as a key driver of some asthma phenotypes. Objective: To derive gene signatures from in vitro studies of IL‐33‐stimulated cells and use these to determine IL‐33‐associated enrichment patterns in asthma. Methods: Signatures downstream of IL‐33 stimulation were derived from our in vitro study of human mast cells and from public datasets of in vitro stimulated human basophils, type 2 innate lymphoid cells (ILC2), regulatory T cells (Treg) and endothelial cells. Gene Set Variation Analysis (GSVA) was used to probe U‐BIOPRED and ADEPT sputum transcriptomics to determine enrichment scores (ES) for each signature according to asthma severity, sputum granulocyte status and previously defined molecular phenotypes. Results: IL‐33‐activated gene signatures were cell‐specific with little gene overlap. Individual signatures, however, were associated with similar signalling pathways (TNF, NF‐κB, IL‐17 and JAK/STAT signalling) and immune cell differentiation pathways (Th17, Th1 and Th2 differentiation). ES for IL‐33‐activated gene signatures were significantly enriched in asthmatic sputum, particularly in patients with neutrophilic and mixed granulocytic phenotypes. IL‐33 mRNA expression was not elevated in asthma whereas the expression of mRNA for IL1RL1, the IL‐33 receptor, was up‐regulated in the sputum of severe eosinophilic asthma. The mRNA expression for IL1RAP, the IL1RL1 co‐receptor, was greatest in severe neutrophilic and mixed granulocytic asthma. Conclusions: IL‐33‐activated gene signatures are elevated in neutrophilic and mixed granulocytic asthma corresponding with IL1RAP co‐receptor expression. This suggests incorporating T2‐low asthma in anti‐IL‐33 trials. [ABSTRACT FROM AUTHOR]

The airway epithelium is remodelled in patients with SA and plays a pivotal role in orchestrating airway inflammation.1 However, airway epithelial cell-directed therapies have not been explored due to the lack of specific targets. CEACAM5 is an IL-13-regulated epithelial gene that mediates transcription in type-2 (T2) high severe asthma Severe asthma (SA) is a heterogeneous disease characterized by airflow restriction, frequent exacerbations and lack of effective treatments that improve quality of life and prevent exacerbations. [Extracted from the article]

Keywords: asthma; bioinformatics; endotypes; precision medicine; systems biology EN asthma bioinformatics endotypes precision medicine systems biology 380 383 4 01/09/21 20210101 NES 210101 I To the Editor, i Asthma is a complex heterogeneous disease that presents with varying degrees of severity. We identified four optimal clusters (TAC*1, TAC*2, TAC*3a and TAC*3b) (Figure S3), in agreement with our previous clustering1 where TAC*3a and TAC*3b were combined. Asthma, bioinformatics, endotypes, precision medicine, systems biology. [Extracted from the article]

ABSTRACT Background and objective Nuclear factor kappa B ( NF-kB)-mediated inflammatory gene expression and vascular endothelial cell proliferation/remodelling are implicated in the pathophysiology of the fatal disease, pulmonary arterial hypertension ( PAH). Bromodomain and extra-terminal ( BET) proteins are essential for the expression of a subset of NF-kB-induced inflammatory genes. BET mimics including JQ1+ prevent binding of BETs to acetylated histones and down-regulate the expression of selected genes. Methods The effects of JQ1+ on the proliferation of primary human pulmonary microvascular endothelial cells ( HPMECs) from healthy subjects were measured by bromodeoxyuridine ( BrdU) incorporation. Cell cycle progression was assessed by flow cytometry; mRNA and protein levels of cyclin-dependent kinases ( CDKs), inhibitors and cytokines were determined by reverse transcription-quantitative PCR ( RT-qPCR), Western blotting or ELISA. Histone acetyltransferase ( HAT) and deacetylase ( HDAC) activities were determined in nuclear extracts from whole lung of PAH and control patients. Results JQ1+ significantly inhibited IL6 and IL8 ( IL6 and CXCL8) mRNA and protein in HPMECs compared with its inactive enantiomer JQ1−. JQ1+ decreased NF-kB p65 recruitment to native IL6 and IL8 promoters. JQ1+ showed a concentration-dependent decrease in HPMEC proliferation compared with JQ1−-treated cells. JQ1+ induced G1 cell cycle arrest by increasing the expression of the CDK inhibitors (CDKN) 1A (p21cip) and CDKN2D ( p19INK4D ) and decreasing that of CDK2, CDK4 and CDK6. JQ1+ also inhibited serum-stimulated migration of HPMECs. Finally, HAT activity was significantly increased in the lung of PAH patients. Conclusion Inhibition of BETs in primary HPMECs decreases inflammation and remodelling. BET proteins could be a target for future therapies for PAH. [ABSTRACT FROM AUTHOR]