Meteorin-β/Meteorin like/IL-41 attenuates airway inflammation in house dust mite-induced allergic asthma

We sought to examine the regulatory effect of Meteorin-β(Metrnβ)/Meteorin like(Metrnl)/IL-41 on lung inflammation in allergic asthma.We found that Metrnβwas elevated significantly in asthmatic patients and in mice with allergic asthma induced by house dust mite(HDM)extract.Upon exposure to HDM,Metrnβwas secreted predominantly by airway epithelial cells and inflammatory cells,including macrophages and eosinophils.The increased Metrnβeffectively blocked the development of airway hyperreactivity(AHR)and decreased inflammatory cell airway infiltration and type 2 cytokine production,which was associated with downregulated DC-mediated adaptive immune responses.Moreover,Metrnβimpaired the maturation and function of bone marrow-derived dendritic cells in vitro.Asthmatic mice adoptively transferred with dendritic cells isolated from Metrnβ-treated allergic mice displayed decreased AHR,airway inflammation,and lung injury.Metrnβalso displayed anti-inflammatory properties in immunodeficient SCID mice with allergic asthma and in in vitro 3D ALI airway models.Moreover,blockade of Metrnβby anti-Metrnβantibody treatment promoted the development of allergic asthma.These results revealed the unappreciated protective roles of Metrnβin alleviating DC-mediated Th2 inflammation in allergic asthma,providing the novel treatment strategy of therapeutic targeting of Metrnβin allergic asthma.

Anti-inflammatory mechanisms of the novel cytokine interleukin-38 in allergic asthma

We elucidated the anti-inflammatory mechanisms of IL-38 in allergic asthma.Human bronchial epithelial cells and eosinophils were cocultured upon stimulation with the viral RLR ligand poly(I:C)/LyoVec or infection-related cytokine TNF-αto induce expression of cytokines/chemokines/adhesion molecules.House dust mite(HDM)-induced allergic asthma and humanized allergic asthma NOD/SCID murine models were established to assess anti-inflammatory mechanisms in vivo.IL-38 significantly inhibited induced proinflammatory IL-6,IL-1β,CCL5,and CXCL10 production,and antiviral interferon-βand intercellular adhesion molecule-1 expression in the coculture system.Mass cytometry and RNA-sequencing analysis revealed that IL-38 could antagonize the activation of the intracellular STAT1,STAT3,p38 MAPK,ERK1/2,and NF-κB pathways,and upregulate the expression of the host defense-related gene POU2AF1 and anti-allergic response gene RGS13.Intraperitoneal injection of IL-38 into HDM-induced allergic asthma mice could ameliorate airway hyperreactivity by decreasing the accumulation of eosinophils in the lungs and inhibiting the expression of the Th2-related cytokines IL-4,IL-5,and IL-13 in the bronchoalveolar lavage fluid(BALF)and lung homogenates.Histological examination indicated lung inflammation was alleviated by reductions in cell infiltration and goblet cell hyperplasia,together with reduced Th2,Th17,and innate lymphoid type 2 cell numbers but increased proportions of regulatory T cells in the lungs,spleen,and lymph nodes.IL-38 administration suppressed airway hyperreactivity and asthma-related IL-4 and IL-5 expression in humanized mice,together with significantly decreased CCR3^(+) eosinophil numbers in the BALF and lungs,and a reduced percentage of human CD4^(+)CRTH2^(+)Th2 cells in the lungs and mediastinal lymph nodes.Together,our results demonstrated the anti-inflammatory mechanisms of IL-38 and provided a basis for the development of a regulatory cytokine-based treatment for allergic asthma.