Impact of Cigarette Smoke Exposure on the Lung Fibroblastic Response after Influenza Pneumonia

• DOI: 10.1165/rcmb.2018-0004oc
• Publication Date: 2018-08-15T19:33:54Z
• Authors: Sei Won Lee; Lokesh Sharma; Young Ae Kang; Sang-Hun Kim; Sreelakshmi Chand...; Ashley Losier; Virginia Brady; Santos Bermejo; Nathaniel Andrews; Chang-Min Yoon; Wei Liu; Jung-Yeon Lee; Min-Jong Kang; Charles S. Dela Cruz
• Keywords: Male; 0301 basic medicine; Pulmonary Fibrosis; fibrosis; Pneumonia, Viral; 610; Fibroblasts; fibroblast; influenza virus; smoking; Cigarette Smoking; 3. Good health; Mice, Inbred C57BL; Mice; 03 medical and health sciences; Orthomyxoviridae Infections; Influenza A virus; pneumonia; Animals; Cells, Cultured

Influenza viruses can result in significant lung injury with significant morbidity and mortality. In this study, we evaluated the impact of cigarette smoke (CS) exposure on the pulmonary fibroblastic response after influenza infection. We used a murine model in which animals were exposed to CS or room air and subsequently infected with H1N1 influenza virus. Inflammatory and fibrotic responses were measured at different time points after influenza infection. Primary fibroblasts were isolated from the lungs of mice and their characteristics were evaluated. Exposure to CS significantly increased the amount of collagen in the lungs of mice infected with influenza virus compared with the nonsmoking group at 30 days after infection. Furthermore, the presence of fibroblast-specific protein-positive cells increased in the lungs of influenza-infected mice that were exposed to CS compared with the infection-alone group. The smoking group also showed delays in weight recovery and higher cell counts in BAL fluid after infection. Active transforming growth factor β1 levels in BAL fluid increased in both groups; however, CS-exposed mice had a later surge in active transforming growth factor β1 (Day 24). Ex vivo cultures of lung-derived fibroblasts from CS-exposed mice with influenza infection showed rapid proliferation, increased expression of α-smooth muscle actin-stained stress fibers, and higher expression of growth factors compared with fibroblasts from room air-exposed lungs after infection. These results suggest that CS exposure changes the fibroblastic potential, leading to increased fibrosis after influenza infection.