A novel DNase assay reveals low DNase activity in severe asthma

Annabelle R. Charbit, Maude A. Liegeois, Wilfred W. Raymond, Suzy A.A. Comhair, Mats W. Johansson, Annette T. Hastie, Eugene R. Bleecker, Merritt Fajt, Mario Castro, Kaharu Sumino, Serpil C. Erzurum, Elliot Israel, Nizar N. Jarjour, David T. Mauger, Wendy C. Moore, Sally E. Wenzel, Prescott G. Woodruff, Bruce D. Levy, Monica C. Tang, John V. Fahy

Research output: Contribution to journalArticlepeer-review

Abstract

Secreted deoxyribonucleases (DNases), such as DNase-I and DNase-IL3, degrade extracellular DNA, and endogenous DNases have roles in resolving airway inflammation and guarding against autoimmune responses to nucleotides. Subsets of patients with asthma have high airway DNA levels, but information about DNase activity in health and in asthma is lacking. To characterize DNase activity in health and in asthma, we developed a novel kinetic assay using a Taqman probe sequence that is quickly cleaved by DNase-I to produce a large product signal. We used this kinetic assay to measure DNase activity in sputum from participants in the Severe Asthma Research Program (SARP)-3 (n ¼ 439) and from healthy controls (n ¼ 89). We found that DNase activity was lower than normal in asthma [78.7 relative fluorescence units (RFU)/min vs. 120.4 RFU/min, P < 0.0001]. Compared to patients with asthma with sputum DNase activity in the upper tertile activity levels, those in the lower tertile of sputum DNase activity were characterized clinically by more severe disease and pathologically by airway eosinophilia and airway mucus plugging. Carbamylation of DNase-I, a post-translational modification that can be mediated by eosinophil peroxidase, inactivated DNase-I. In summary, a Taqman probe-based DNase activity assay uncovers low DNase activity in the asthma airway that is associated with more severe disease and airway mucus plugging and may be caused, at least in part, by eosinophil-mediated carbamylation.

Original languageEnglish (US)
Pages (from-to)L796-L804
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume326
Issue number6
DOIs
StatePublished - Jun 2024

All Science Journal Classification (ASJC) codes

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

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