Targeting Cytokines as Evolving Treatment Strategies in Chronic Inflammatory Airway Diseases

Smoke exposure from chronic biomass burning induces distinct accumulative systemic inflammatory cytokine alterations compared to tobacco smoking in healthy women

Long-term exposure to biomass-burning smoke (BS) is associated with chronic obstructive pulmonary disease (COPD), asthma, and other chronic inflammatory lung diseases. BS results from such processes as the burning of wood for indoor cooking and heating, with women and children having the highest exposure rate. This study aimed to analyze the accumulative alterations in cytokine levels associated with BS (from wood) compared to tobacco smoke (TS) in healthy adult women. The levels of 27 cytokines were analyzed in the serum of 100 women, including 40 tobacco smokers/non-exposed to BS (TS+/BS-), 30 never-smokers/exposed to BS (TS-/BS+) and 30 never-smokers/non-exposed to BS (TS-/BS-) as controls, using 27-Plex immunoassay. The chronic BS exposure index was rated at ≥100 h-years, and the tobacco-smoking index was ≥10 pack-years. Compared to TS-/BS-, TS+/BS- had higher levels of IL-2, IL-9, MCP-1, MIP-1β, and VEGF, while TS-/BS+ showed higher levels of IL-1ra, IL-6, IL-8, Eotaxin, IP-10, RANTES, and VEGF, presenting a distinct inflammatory profile that may favor an eosinophil-derived inflammatory response to BS exposure. Compared to TS+/BS-, TS-/BS+ expressed higher levels of IP-10 and IL-8, but lower levels of IL-2 and MIP-1β. Gene-disease database analysis showed that altered cytokines in both TS+/BS- and TS-/BS+ are associated with asthma, COPD, lung fibrosis, and lung cancer. In conclusion, chronic BS exposure induces distinct systemic inflammatory cytokine alterations compared to tobacco smokers in healthy women. These findings provide new insights into how long-term exposure to BS affects the inflammatory response-and potentially the health-of adult women.

Salidroside suppresses group 2 innate lymphoid cell-mediated allergic airway inflammation by targeting IL-33/ST2 axis

Salidroside, an active component extracted from Rhodiola rosea, has been reported to inhibit allergic asthma. However, its mechanism has not been fully elucidated. Group 2 innate lymphoid cells (ILC2s) accumulate in the lung and cooperate with other cells to drive type 2 inflammation stimulated by inhaled allergens. The study aims to explore the suppressive effect of salidroside on ILC2s and IL-33/IL-33R (ST2) axis in allergic airway inflammation. The ovalbumin (OVA)-sensitized/challenged mice were established. Airway eosinophil recruitment, increased total IgE in the serum and type 2 cytokines IL-4, IL-5, and IL-13 in the bronchoalveolar lavage fluids and lung tissues were identified in the OVA-induced mice model, all of which were inhibited by pretreatment with different doses of salidroside. Moreover, salidroside suppressed lung total ILC2 and ST2-expressing ILC2 accumulation, lung IL-33 and ST2 expressions in mice. In vitro, OVA could induce IL-33 expression in BEAS-2B cells, which was also effectively inhibited by salidroside. This study firstly reveals salidroside as a potential therapeutic drug for allergic asthma by inhibiting ILC2-mediated airway inflammation via targeting IL-33/ST2 axis.

IL-33 blockade affects mediators of persistence and exacerbation in a model of chronic airway inflammation

BACKGROUND

Severe inflammatory airway diseases are associated with inflammation that does not resolve, leading to structural changes and an overall environment primed for exacerbations.

OBJECTIVE

We sought to identify and inhibit pathways that perpetuate this heightened inflammatory state because this could lead to therapies that allow for a more quiescent lung that is less predisposed to symptoms and exacerbations.

METHODS

Using prolonged exposure to house dust mite in mice, we developed a mouse model of persistent and exacerbating airway disease characterized by a mixed inflammatory phenotype.

RESULTS

We show that lung IL-33 drives inflammation and remodeling beyond the type 2 response classically associated with IL-33 signaling. IL-33 blockade with an IL-33 neutralizing antibody normalized established inflammation and improved remodeling of both the lung epithelium and lung parenchyma. Specifically, IL-33 blockade normalized persisting and exacerbating inflammatory end points, including eosinophilic, neutrophilic, and ST2⁺CD4⁺ T-cell infiltration. Importantly, we identified a key role for IL-33 in driving lung remodeling because anti-IL-33 also re-established the presence of ciliated cells over mucus-producing cells and decreased myofibroblast numbers, even in the context of continuous allergen exposure, resulting in improved lung function.

CONCLUSION

Overall, this study shows that increased IL-33 levels drive a self-perpetuating amplification loop that maintains the lung in a state of lasting inflammation and remodeled tissue primed for exacerbations. Thus IL-33 blockade might ameliorate symptoms and prevent exacerbations by quelling persistent inflammation and airway remodeling.

Progression of Cystic Fibrosis Lung Disease from Childhood to Adulthood: Neutrophils, Neutrophil Extracellular Trap (NET) Formation, and NET Degradation

Genetic defects in cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene cause CF. Infants with CFTR mutations show a peribronchial neutrophil infiltration prior to the establishment of infection in their lung. The inflammatory response progressively increases in children that include both upper and lower airways. Infectious and inflammatory response leads to an increase in mucus viscosity and mucus plugging of small and medium-size bronchioles. Eventually, neutrophils chronically infiltrate the airways with biofilm or chronic bacterial infection. Perpetual infection and airway inflammation destroy the lungs, which leads to increased morbidity and eventual mortality in most of the patients with CF. Studies have now established that neutrophil cytotoxins, extracellular DNA, and neutrophil extracellular traps (NETs) are associated with increased mucus clogging and lung injury in CF. In addition to opportunistic pathogens, various aspects of the CF airway milieux (e.g., airway pH, salt concentration, and neutrophil phenotypes) influence the NETotic capacity of neutrophils. CF airway milieu may promote the survival of neutrophils and eventual pro-inflammatory aberrant NETosis, rather than the anti-inflammatory apoptotic death in these cells. Degrading NETs helps to manage CF airway disease; since DNAse treatment release cytotoxins from the NETs, further improvements are needed to degrade NETs with maximal positive effects. Neutrophil-T cell interactions may be important in regulating viral infection-mediated pulmonary exacerbations in patients with bacterial infections. Therefore, clarifying the role of neutrophils and NETs in CF lung disease and identifying therapies that preserve the positive effects of neutrophils, while reducing the detrimental effects of NETs and cytotoxic components, are essential in achieving innovative therapeutic advances.