| First Author | Caffrey AK | Year | 2015 |
| Journal | PLoS Pathog | Volume | 11 |
| Issue | 1 | Pages | e1004625 |
| PubMed ID | 25629406 | Mgi Jnum | J:248552 |
| Mgi Id | MGI:5919882 | Doi | 10.1371/journal.ppat.1004625 |
| Citation | Caffrey AK, et al. (2015) IL-1alpha signaling is critical for leukocyte recruitment after pulmonary Aspergillus fumigatus challenge. PLoS Pathog 11(1):e1004625 |
| abstractText | Aspergillus fumigatus is a mold that causes severe pulmonary infections. Our knowledge of how A. fumigatus growth is controlled in the respiratory tract is developing, but still limited. Alveolar macrophages, lung resident macrophages, and airway epithelial cells constitute the first lines of defense against inhaled A. fumigatus conidia. Subsequently, neutrophils and inflammatory CCR2+ monocytes are recruited to the respiratory tract to prevent fungal growth. However, the mechanism of neutrophil and macrophage recruitment to the respiratory tract after A. fumigatus exposure remains an area of ongoing investigation. Here we show that A. fumigatus pulmonary challenge induces expression of the inflammasome-dependent cytokines IL-1beta and IL-18 within the first 12 hours, while IL-1alpha expression continually increases over at least the first 48 hours. Strikingly, Il1r1-deficient mice are highly susceptible to pulmonary A. fumigatus challenge exemplified by robust fungal proliferation in the lung parenchyma. Enhanced susceptibility of Il1r1-deficient mice correlated with defects in leukocyte recruitment and anti-fungal activity. Importantly, IL-1alpha rather than IL-1beta was crucial for optimal leukocyte recruitment. IL-1alpha signaling enhanced the production of CXCL1. Moreover, CCR2+ monocytes are required for optimal early IL-1alpha and CXCL1 expression in the lungs, as selective depletion of these cells resulted in their diminished expression, which in turn regulated the early accumulation of neutrophils in the lung after A. fumigatus challenge. Enhancement of pulmonary neutrophil recruitment and anti-fungal activity by CXCL1 treatment could limit fungal growth in the absence of IL-1alpha signaling. In contrast to the role of IL-1alpha in neutrophil recruitment, the inflammasome and IL-1beta were only essential for optimal activation of anti-fungal activity of macrophages. As such, Pycard-deficient mice are mildly susceptible to A. fumigatus infection. Taken together, our data reveal central, non-redundant roles for IL-1alpha and IL-1beta in controlling A. fumigatus infection in the murine lung. |
