TY - JOUR
T1 - Autophagy regulates DUOX1 localization and superoxide production in airway epithelial cells during chronic IL-13 stimulation
AU - Dickinson, John D.
AU - Sweeter, Jenea M.
AU - Warren, Kristi J.
AU - Ahmad, Iman M.
AU - De Deken, Xavier
AU - Zimmerman, Matthew C.
AU - Brody, Steven L.
N1 - Funding Information:
We thank Sean Gunsten for assistance with primary cell culture, Elizabeth Staab for assistance with the OVA challenged mouse model, and Jeff Haspel for his helpful comments. This work was supported by NIH Grants 1K08HL131992 - 01 (JDD) and R01HL122585 (SLB) and the Hubert C. and Dorothy R. Moog Professorship (SLB). EPR Spectroscopy data was collected in the University of Nebraska's EPR Spectroscopy Core, which is supported, in part, by a NIH grant from the National Institute of General Medical Sciences of the ( P30GM103335 ) awarded to the University of Nebraska's Redox Biology Center. Appendix A
Publisher Copyright:
© 2017 The Authors
PY - 2018/4
Y1 - 2018/4
N2 - The airway epithelium is a broad interface with the environment, mandating well-orchestrated responses to properly modulate inflammation. Classically, autophagy is a homeostatic pathway triggered in response to external cellular stresses, and is elevated in chronic airway diseases. Recent findings highlight the additional role of autophagy in vesicle trafficking and protein secretion, implicating autophagy pathways in complex cellular responses in disease. Th2 cytokines, IL-13 and IL-4, are increased in asthma and other airway diseases contributing to chronic inflammation. Previously, we observed that IL-13 increases reactive oxygen species (ROS) in airway epithelial cells in an autophagy-dependent fashion. Here, we tested our hypothesis that autophagy is required for IL-13-mediated superoxide production via the NADPH oxidase DUOX1. Using a mouse model of Th2-mediated inflammation induced by OVA-allergen, we observed elevated lung amounts of IL-13 and IL-4 accompanied by increased autophagosome levels, determined by LC3BII protein levels and immunostaining. ROS levels were elevated and DUOX1 expression was increased 70-fold in OVA-challenged lungs. To address the role of autophagy and ROS in the airway epithelium, we treated primary human tracheobronchial epithelial cells with IL-13 or IL-4. Prolonged, 7-day treatment increased autophagosome formation and degradation, while brief activation had no effect. Under parallel culture conditions, IL-13 and IL-4 increased intracellular superoxide levels as determined by electron paramagnetic resonance (EPR) spectroscopy. Prolonged IL-13 activation increased DUOX1, localized at the apical membrane. Silencing DUOX1 by siRNA attenuated IL-13-mediated increases in superoxide, but did not reduce autophagy activities. Notably, depletion of autophagy regulatory protein ATG5 significantly reduced superoxide without diminishing total DUOX1 levels. Depletion of ATG5, however, diminished DUOX1 localization at the apical membrane. The findings suggest non-canonical autophagy activity regulates DUOX1-dependent localization required for intracellular superoxide production during Th2 inflammation. Thus, in chronic Th2 inflammatory airway disease, autophagy proteins may be responsible for persistent intracellular superoxide production.
AB - The airway epithelium is a broad interface with the environment, mandating well-orchestrated responses to properly modulate inflammation. Classically, autophagy is a homeostatic pathway triggered in response to external cellular stresses, and is elevated in chronic airway diseases. Recent findings highlight the additional role of autophagy in vesicle trafficking and protein secretion, implicating autophagy pathways in complex cellular responses in disease. Th2 cytokines, IL-13 and IL-4, are increased in asthma and other airway diseases contributing to chronic inflammation. Previously, we observed that IL-13 increases reactive oxygen species (ROS) in airway epithelial cells in an autophagy-dependent fashion. Here, we tested our hypothesis that autophagy is required for IL-13-mediated superoxide production via the NADPH oxidase DUOX1. Using a mouse model of Th2-mediated inflammation induced by OVA-allergen, we observed elevated lung amounts of IL-13 and IL-4 accompanied by increased autophagosome levels, determined by LC3BII protein levels and immunostaining. ROS levels were elevated and DUOX1 expression was increased 70-fold in OVA-challenged lungs. To address the role of autophagy and ROS in the airway epithelium, we treated primary human tracheobronchial epithelial cells with IL-13 or IL-4. Prolonged, 7-day treatment increased autophagosome formation and degradation, while brief activation had no effect. Under parallel culture conditions, IL-13 and IL-4 increased intracellular superoxide levels as determined by electron paramagnetic resonance (EPR) spectroscopy. Prolonged IL-13 activation increased DUOX1, localized at the apical membrane. Silencing DUOX1 by siRNA attenuated IL-13-mediated increases in superoxide, but did not reduce autophagy activities. Notably, depletion of autophagy regulatory protein ATG5 significantly reduced superoxide without diminishing total DUOX1 levels. Depletion of ATG5, however, diminished DUOX1 localization at the apical membrane. The findings suggest non-canonical autophagy activity regulates DUOX1-dependent localization required for intracellular superoxide production during Th2 inflammation. Thus, in chronic Th2 inflammatory airway disease, autophagy proteins may be responsible for persistent intracellular superoxide production.
KW - Asthma
KW - Autophagy
KW - DUOX1
KW - Electron Paramagnetic Resonance Spectroscopy
KW - Epithelial cells
KW - IL-13
KW - IL-4
KW - Reactive oxygen species
KW - Superoxide
UR - http://www.scopus.com/inward/record.url?scp=85030329063&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85030329063&partnerID=8YFLogxK
U2 - 10.1016/j.redox.2017.09.013
DO - 10.1016/j.redox.2017.09.013
M3 - Article
C2 - 28982074
AN - SCOPUS:85030329063
VL - 14
SP - 272
EP - 284
JO - Redox Biology
JF - Redox Biology
SN - 2213-2317
ER -