Influenza-mediated reduction of lung epithelial ion channel activity leads to dysregulated pulmonary fluid homeostasis
Jeffrey D. Brand, … , Sadis Matalon, Kevin S. Harrod
Jeffrey D. Brand, … , Sadis Matalon, Kevin S. Harrod
Published October 18, 2018
Citation Information: JCI Insight. 2018;3(20):e123467. https://doi.org/10.1172/jci.insight.123467.
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Research Article Pulmonology Virology

Influenza-mediated reduction of lung epithelial ion channel activity leads to dysregulated pulmonary fluid homeostasis

Abstract

Severe influenza (IAV) infection can develop into bronchopneumonia and edema, leading to acquired respiratory distress syndrome (ARDS) and pathophysiology. Underlying causes for pulmonary edema and aberrant fluid regulation largely remain unknown, particularly regarding the role of viral-mediated mechanisms. Herein, we show that distinct IAV strains reduced the functions of the epithelial sodium channel (ENaC) and the cystic fibrosis transmembrane regulator (CFTR) in murine respiratory and alveolar epithelia in vivo, as assessed by measurements of nasal potential differences and single-cell electrophysiology. Reduced ion channel activity was distinctly limited to virally infected cells in vivo and not bystander uninfected lung epithelium. Multiple lines of evidence indicated ENaC and CFTR dysfunction during the acute infection period; however, only CFTR dysfunction persisted beyond the infection period. ENaC, CFTR, and Na,K-ATPase activities and protein levels were also reduced in virally infected human airway epithelial cells. Reduced ENaC and CFTR led to changes in airway surface liquid morphology of human tracheobronchial cultures and airways of IAV-infected mice. Pharmacologic correction of CFTR function ameliorated IAV-induced physiologic changes. These changes are consistent with mucous stasis and pulmonary edema; furthermore, they indicate that repurposing therapeutic interventions correcting CFTR dysfunction may be efficacious for treatment of IAV lung pathophysiology.

Authors

Jeffrey D. Brand, Ahmed Lazrak, John E. Trombley, Ren-Jay Shei, A. Timothy Adewale, Jennifer L. Tipper, Zhihong Yu, Amit R. Ashtekar, Steven M. Rowe, Sadis Matalon, Kevin S. Harrod

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Figure 1

IAV infection reduces ENaC and CFTR function in vivo.

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IAV infection reduces ENaC and CFTR function in vivo. Mice were infected...
Mice were infected with 4,000 PFU of PR8ΔGFP. NPD of control and infected mice were measured as described in Methods. (A) Recording traces depicting NPD in noninfected control mice, immediately after the probe was inserted in one the mouse nares; a negative voltage deflection was recorded and is indicative of the active Na+ ion absorption. Addition of 200 μM amiloride in the perfusate inhibited the voltage difference, indicating the role of ENaC in maintaining the initially recorded NPD. Subsequent perfusion with 10–20 μM forskolin activated a second potential difference due to the movement of Cl– and HCO3–, which was inhibited by 50 μM GlyH-101, showing the role of CFTR in this process. Representative NPD recordings from uninfected (Control) mice, 5 and 15 days p.i. are shown, with the electrical potential scale noted for each time point (bottom left). (B) ENaC activity, as measured by NPD across time course of IAV. Scatter plots with NPD value ± SEM at 2, 5, 10, and 15 days p.i. (C) Scatter plots of GlyH-101–sensitive (CFTR) NPD at days 2, 5, 10, and 15 p.i. Each data point corresponds to a single mouse, N = 9–13 per group; mean ± SEM. Significance was determined by 1-way ANOVA and post hoc Tukey test for multiple comparisons. *P < 0.0001 compared with noninfected controls.