Human epithelial (A549) cells exposed to hyperoxia die by cellular necrosis. In the current study, we demonstrated the involvement of apoptogenic factors in epithelial cell necrosis in response to hyperoxia, including the formation of the Fas-related death-inducing signaling complex and initiation of mitochondria-dependent apoptotic pathways. We showed increased activation of both Bid and Bax in A549 cells subjected to hyperoxia. Bax activation involved a Bid-assisted conformational change. We discovered that the response to hyperoxia in vivo predominantly involved the activation of the Bid/caspase-8 pathway without apparent increases in Bax expression. Disruption of the Bid pathway by gene deletion protected against cell death in vivo and in vitro. Likewise, inhibition of caspase-8 by Flip also protected against cell death. Taken together, we have demonstrated the involvement of apoptogenic factors in epithelial cell responses to hyperoxia, despite a final outcome of cellular necrosis. We have, for the first time, identified a predominant role for the caspase-8/Bid pathway in signaling associated with hyperoxic lung injury and cell death in vivo and in vitro.
Necrotic Cell Death in Response to Oxidant Stress Involves the Activation of the Apoptogenic Caspase-8/Bid Pathway*
Xue Wang,S. Ryter,Chunsun Dai,Zi-Lue Tang,Simon C Watkins,Xiao-Ming Yin,R. Song,A. Choi
Published 2003 in Journal of Biological Chemistry
ABSTRACT
PUBLICATION RECORD
- Publication year
2003
- Venue
Journal of Biological Chemistry
- Publication date
2003-08-01
- Fields of study
Biology, Medicine
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
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