| First Author | Lewis BW | Year | 2017 |
| Journal | J Immunol | Volume | 199 |
| Issue | 3 | Pages | 1170-1183 |
| PubMed ID | 28667160 | Mgi Jnum | J:254542 |
| Mgi Id | MGI:6100221 | Doi | 10.4049/jimmunol.1700144 |
| Citation | Lewis BW, et al. (2017) Early Postnatal Secondhand Smoke Exposure Disrupts Bacterial Clearance and Abolishes Immune Responses in Muco-Obstructive Lung Disease. J Immunol 199(3):1170-1183 |
| abstractText | Secondhand smoke (SHS) exposure has been linked to the worsening of ongoing lung diseases. However, whether SHS exposure affects the manifestation and natural history of imminent pediatric muco-obstructive airway diseases such as cystic fibrosis remains unclear. To address these questions, we exposed Scnn1b transgenic (Scnn1b-Tg(+)) mice to SHS from postnatal day (PND) 3-21 and lung phenotypes were examined at PND22. Although a majority of filtered air (FA)-exposed Scnn1b-Tg(+) (FA-Tg(+)) mice successfully cleared spontaneous bacterial infections by PND22, the SHS-exposed Scnn1b-Tg(+) (SHS-Tg(+)) mice failed to resolve these infections. This defect was associated with suppressed antibacterial defenses, i.e., phagocyte recruitment, IgA secretion, and Muc5b expression. Whereas the FA-Tg(+) mice exhibited marked mucus obstruction and Th2 responses, SHS-Tg(+) mice displayed a dramatic suppression of these responses. Mechanistically, downregulated expression of IL-33, a stimulator of type II innate lymphoid cells, in lung epithelial cells was associated with suppression of neutrophil recruitment, IgA secretions, Th2 responses, and delayed bacterial clearance in SHS-Tg(+) mice. Cessation of SHS exposure for 21 d restored previously suppressed responses, including phagocyte recruitment, IgA secretion, and mucous cell metaplasia. However, in contrast with FA-Tg(+) mice, the SHS-Tg(+) mice had pronounced epithelial necrosis, alveolar space consolidation, and lymphoid hyperplasia; indicating lagged unfavorable effects of early postnatal SHS exposure in later life. Collectively, our data show that early postnatal SHS exposure reversibly suppresses IL-33 levels in airspaces which, in turn, results in reduced neutrophil recruitment and diminished Th2 response. Our data indicate that household smoking may predispose neonates with muco-obstructive lung disease to bacterial exacerbations. |
