Although group 2 Innate Lymphoid Cells (ILC2s) play important roles in driving the pathogenesis of allergic airway
inflammation, the molecular mechanisms regulating ILC2 responses remain to be fully elucidated.
Adenosine signaling is emerging as an important factor to limit excessive
inflammation and tissue damage, its role in ILC2-driven airway
inflammation remains to be understood. Here we identify
adenosine as a negative regulator of ILC2s and allergic airway
inflammation. Elevation of
adenosine was observed in lungs after
protease papain challenge.
Adenosine receptor A2A was abundantly expressed in lung ILC2s. The
adenosine analog
NECA significantly suppress ILC2s responses and relieved airway
inflammation induced by
IL-33 or
papain. Conversely, blockage of
adenosine synthesis by CD73 inhibitor
APCP or deficiency of A2A aggravated murine airway
inflammation. Adoptive transfer of ILC2s into immunodeficiency NCG mice demonstrated that the regulation of ILC2 by
adenosine was cell intrinsic. Mechanistic studies showed that the effects of
adenosine on ILC2s were associated with changes in transcriptional profiling, and the elevation of intracellular cAMP and resulted NF-κB downregulation. These observations indicate that adenosine-A2A signaling is a negative regulator of ILC2s, which confers protection against airway
inflammation and represents a novel therapeutic target for controlling
asthma.