An epithelial gene signature of trans-IL-6 signaling defines a subgroup of type 2-low asthma.

BACKGROUND: Asthma is stratified into type 2-high and type 2-low inflammatory phenotypes. Limited success has been achieved in developing drugs that target type 2-low inflammation. Previous studies have linked IL-6 signaling to severe asthma. IL-6 cooperates with soluble-IL-6Rα to activate cell signaling in airway epithelium. OBJECTIVE: We sought to study the role of sIL-6Rα amplified IL-6 signaling in airway epithelium and to develop an IL-6+ sIL-6Rα gene signature that may be used to select asthma patients who potentially respond to anti-IL-6 therapy. METHODS: Human airway epithelial cells were stimulated with combinations of IL-6, sIL-6Rα, and inhibitors, sgp130 (Olamkicept), and anti-IL-6R (Tocilizumab), to assess effects on pathway activation, epithelial barrier integrity, and gene expression. A gene signature was generated to identify IL-6 high patients using bronchial biopsies and nasal brushes. RESULTS: Soluble-IL-6Rα amplified the activation of the IL-6 pathway, shown by the increase of STAT3 phosphorylation and stronger gene induction in airway epithelial cells compared to IL-6 alone. Olamkicept and Tocilizumab inhibited the effect of IL-6 + sIL-6Rα on gene expression. We developed an IL-6 + sIL-6Rα gene signature and observed enrichment of this signature in bronchial biopsies but not nasal brushes from asthma patients compared to healthy controls. An IL-6 + sIL-6Rα gene signature score was associated with lower levels of sputum eosinophils in asthma. CONCLUSION: sIL-6Rα amplifies IL-6 signaling in bronchial epithelial cells. Higher local airway IL-6 + sIL-6Rα signaling is observed in asthma patients with low sputum eosinophils.

Current Smoking Alters Gene Expression and DNA Methylation in the Nasal Epithelium of Patients with Asthma.

Current smoking contributes to worsened asthma prognosis and more severe symptoms and limits the beneficial effects of corticosteroids. As the nasal epithelium can reflect smoking-induced changes in the lower airways, it is a relevant source to investigate changes in gene expression and DNA methylation. This study explores gene expression and DNA methylation changes in current and ex-smokers with asthma. Matched gene expression and epigenome-wide DNA methylation samples collected from nasal brushings of 55 patients enrolled in a clinical trial investigation of current and ex-smoker patients with asthma were analyzed. Differential gene expression and DNA methylation analyses were conducted comparing current smokers with ex-smokers. Expression quantitative trait methylation (eQTM) analysis was completed to explore smoking-relevant genes by CpG sites that differ between current and ex-smokers. To investigate the relevance of the smoking-associated DNA methylation changes for the lower airways, significant CpG sites were explored in bronchial biopsies from patients who had stopped smoking. A total of 809 genes and 18,814 CpG sites were differentially associated with current smoking in the nose. The cis-eQTM analysis uncovered 171 CpG sites with a methylation status associated with smoking-related gene expression, including AHRR, ALDH3A1, CYP1A1, and CYP1B1. The methylation status of CpG sites altered by current smoking reversed with 1 year of smoking cessation. We confirm that current smoking alters epigenetic patterns and affects gene expression in the nasal epithelium of patients with asthma, which is partially reversible in bronchial biopsies after smoking cessation. We demonstrate the ability to discern molecular changes in the nasal epithelium, presenting this as a tool in future investigations into disease-relevant effects of tobacco smoke.

Chronic Social Defeat Stress Shifts Peripheral Circadian Clocks in Male Mice in a Tissue-Specific and Time-of-Day Dependent Fashion.

Uncontrollable stress is linked to the development of many diseases, some of which are associated with disrupted daily rhythms in physiology and behavior. While available data indicate that the master circadian pacemaker in the suprachiasmatic nucleus (SCN) is unaffected by stress, accumulating evidence suggest that circadian oscillators in peripheral tissues and organs can be shifted by a variety of stressors and stress hormones. In the present study, we examined effects of acute and chronic social defeat stress in mice and addressed the question of whether effects of uncontrollable stress on peripheral clocks are tissue specific and depend on time of day of stress exposure. We used mice that carry a luciferase reporter gene fused to the circadian clock gene Period2 (PER2::LUC) to examine daily rhythms of PER2 expression in various peripheral tissues. Mice were exposed to social defeat stress in the early (ZT13-14) or late (ZT21-22) dark phase, either once (acute stress) or repeatedly on 10 consecutive days (chronic stress). One hour after the last stressor, tissue samples from liver, lung, kidney, and white adipose tissue (WAT) were collected. Social defeat stress caused a phase delay of several hours in the rhythm of PER2 expression in lung and kidney, but this delay was stronger after chronic than after acute stress. Moreover, shifts only occurred after stress in the late dark phase, not in the early dark phase. PER2 rhythms in liver and WAT were not significantly shifted by social defeat, suggesting a different response of various peripheral clocks to stress. This study indicates that uncontrollable social defeat stress is capable of shifting peripheral clocks in a time of day dependent and tissue specific manner. These shifts in peripheral clocks were smaller or absent after a single stress exposure and may therefore be the consequence of a cumulative chronic stress effect.