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 2

Effect of i.n. exposure to DNA, Nuc, and Alt (alone or in combination) on mouse AHR, inflammation, and mucus production.

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Effect of i.n. exposure to DNA, Nuc, and Alt (alone or in combination) o...
(A) A schematic of the i.n. administration of various agents and the experimental end point. (B) AHR after Sal, DNA, Alt, or Alt+DNA exposure as measured by flexiVent. εSal versus Alt+DNA, P < 0.0001; φSal versus Alt, P < 0.0001; #DNA versus Alt, P = 0.0001; δDNA versus Alt+DNA, P < 0.0001. (C–F) Differential counts of BAL macrophages, lymphocytes, eosinophils, and neutrophils (n = 5). (G and H) Morphometric quantification of peribronchial and perivascular inflammation (H&E staining of the lungs) and mucus production (PAS staining) in Sal-, DNA-, Alt-, or Alt+DNA–treated mice (n = 5). (Groups are color-coded as in B). (I) AHR after Sal, Nuc, Alt, or Alt-Nuc exposure as measured by flexiVent. RRS, respiratory system resistance. *Sal versus Nuc, P = 0.02; φSal versus Alt, P < 0.0001; εSal versus Alt-Nuc, P < 0.0001; #Nuc versus Alt, P = 0.02; δNuc versus Alt-Nuc, P < 0.0001; ψAlt versus Alt-Nuc, P = 0.006. (n = 7). (J–M) Differential counts of BAL macrophages, lymphocytes, eosinophils, and neutrophils (n = 7). (N and O) Morphometric quantification of peribronchial and perivascular inflammation and mucus production in mice treated with Sal, Nuc, Alt, or Alt-Nuc (n = 7). BM, basement membrane. (Groups are color coded as in I). (P and Q) Expression (semi-quantitative) of select cytokines and chemokines in BAL from mice treated with Sal, Nuc, Alt or Alt-Nuc, as measured by a cytokine array (n = 3). (R) AHR after Sal, DNA, or histone exposure in B6 mice (n = 5). δSal versus histone, P < 0.001; εDNA versus histone, P < 0.001. A 2-way ANOVA with Tukey’s multiple comparisons test was used to determine the statistical significance between groups. Data are presented as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001. ****P < 0.0001.