Allergens abrogate antiinflammatory DNA effects and unmask macrophage-driven neutrophilic asthma via ILC2/STING/TNF-α signaling
Anand Sripada, Divya Verma, Rangati Varma, Kapil Sirohi, Carolyn Kwiat, Mohini Pathria, Mukesh Verma, Anita Sahu, Vamsi Guntur, Laurie Manka, Brian Vestal, Camille Moore, Richard J. Martin, Magdalena M. Gorska, John Cambier, Andrew Getahun, Rafeul Alam
Anand Sripada, Divya Verma, Rangati Varma, Kapil Sirohi, Carolyn Kwiat, Mohini Pathria, Mukesh Verma, Anita Sahu, Vamsi Guntur, Laurie Manka, Brian Vestal, Camille Moore, Richard J. Martin, Magdalena M. Gorska, John Cambier, Andrew Getahun, Rafeul Alam
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Research Article Immunology Inflammation Pulmonology

Allergens abrogate antiinflammatory DNA effects and unmask macrophage-driven neutrophilic asthma via ILC2/STING/TNF-α signaling

Abstract

The mechanisms of neutrophilic and mixed neutrophilic-eosinophilic asthma are poorly understood. We found that extracellular DNA and nucleosomes (Nucs) were elevated in the airways of patients with neutrophilic-eosinophilic asthma and correlated with bronchoalveolar lavage neutrophils. Bronchial tissue from neutrophilic-eosinophilic asthma had more DNA sensor–positive cells. Intranasally administered DNA did not induce airway hyperreactivity (AHR) or any pathology but induced AHR and neutrophilic-eosinophilic inflammation when coadministered with the allergen Alternaria (Alt). Nuc alone induced antiinflammatory/defensive genes, whereas the Nuc-Alt combination increased levels of TNF-α and innate cytokines. The Alt-Nuc phenotype was abolished in Cgas–/–, ALR–/–, Sting–/–, LysMCre:Stingfl/fl, IL7RCre:Rorαfl/fl, and Tnfr2–/– mice. Alt, unexpectedly, played an essential role in the Nuc-induced phenotype. It abrogated Nuc induction of antiinflammatory genes, facilitated Nuc uptake, induced type 2 innate lymphoid cells, which, in the presence of Nuc, produced high levels of TNF-α, and promoted neutrophilic infiltration. We established a paradigm whereby allergens inhibit the antiinflammatory effects of DNA/Nuc and facilitate STING-TNF-α–driven neutrophilic-eosinophilic inflammation in asthma.

Authors

Anand Sripada, Divya Verma, Rangati Varma, Kapil Sirohi, Carolyn Kwiat, Mohini Pathria, Mukesh Verma, Anita Sahu, Vamsi Guntur, Laurie Manka, Brian Vestal, Camille Moore, Richard J. Martin, Magdalena M. Gorska, John Cambier, Andrew Getahun, Rafeul Alam

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Figure 8

Role of TNF-α and TNFR2 in Alt-Nuc–induced asthma.

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Role of TNF-α and TNFR2 in Alt-Nuc–induced asthma. (A) AHR following Alt...
(A) AHR following Alt-Nuc, Alt, Nuc and Sal exposure in WT and Tnfr2–/– mice as measured by flexiVent. RRS, respiratory system resistance. δWT-Sal versus WT-Nuc, P < 0.0001; εWT-Sal versus WT-Alt, P < 0.0001; §WT-Sal versus Tnfr2–/–-Alt, P < 0.0001; *WT-Sal versus WT-Alt-Nuc, P < 0.0001; #WT-Nuc versus WT-Alt, P = 0.006; φWT-Alt versus WT-Alt-Nuc, P < 0.0001; ΨWT-Alt-Nuc versus Tnfr2–/–-Alt-Nuc, P < 0.0001. (n = 5; 2-way ANOVA with Tukey’s multiple comparisons test). (B–E) Quantification of eosinophils and neutrophils in BAL, morphometric quantification of lung inflammation and mucus production in WT and Tnfr2–/– mice treated with Alt-Nuc, Alt, Nuc, or Sal (groups are color-coded as in A). (n = 5; 2-way ANOVA with Tukey’s multiple comparisons test). BM, basement membrane. (F) ICAM1 expression in the lung tissue of WT and Tnfr2–/– mice (n = 4) treated with Alt-Nuc. (G) Quantification of ICAM1 staining intensity in the lung tissue from WT and Tnfr2–/– mice treated with Alt-Nuc. Comparison made by Student’s 2-tailed t test. Scale bar, 50 μm. (H and I) Comparison of TNF-α+ lung hematopoietic cells (frequency and MFI) from the Alt-Nuc model (n = 4). (J and K) TNF-α (ELISA) in BAL from ILC2 KO (IL7RCre:Rorαfl/fl) and Sting–/– mice (n = 4). (L and M) ICAM1 expression (immunostaining and mean intensity quantification) in the lung tissue from Alt-Nuc–treated IL7RCre:Rorαfl/fl and Rorαfl/fl mice (n = 4). Scale bar, 50 μm. Comparison made by Student’s 2-tailed t test. Data are presented as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.