Document Detail


Autophagy protein microtubule-associated protein 1 light chain-3B (LC3B) activates extrinsic apoptosis during cigarette smoke-induced emphysema.
MedLine Citation:
PMID:  20956295     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Chronic obstructive pulmonary disease (COPD) is a debilitating disease caused by chronic exposure to cigarette smoke (CS), which involves airway obstruction and alveolar loss (i.e., emphysema). The mechanisms of COPD pathogenesis remain unclear. Our previous studies demonstrated elevated autophagy in human COPD lung, and as a cellular and tissue response to CS exposure in an experimental model of emphysema in vivo. We identified the autophagic protein microtubule-associated protein 1 light chain-3B (LC3B) as a positive regulator of CS-induced lung epithelial cell death. We now extend these initial observations to explore the mechanism by which LC3B mediates CS-induced apoptosis and emphysema development in vivo. Here, we observed that LC3B(-/-) mice had significantly decreased levels of apoptosis in the lungs after CS exposure, and displayed resistance to CS-induced airspace enlargement, relative to WT littermate mice. We found that LC3B associated with the extrinsic apoptotic factor Fas in lipid rafts in an interaction mediated by caveolin-1 (Cav-1). The siRNA-dependent knockdown of Cav-1 sensitized epithelial cells to CS-induced apoptosis, as evidenced by enhanced death-inducing signaling complex formation and caspase activation. Furthermore, Cav-1(-/-) mice exhibited higher levels of autophagy and apoptosis in the lung in response to chronic CS exposure in vivo. In conclusion, we demonstrate a pivotal role for the autophagic protein LC3B in CS-induced apoptosis and emphysema, suggestive of novel therapeutic targets for COPD treatment. This study also introduces a mechanism by which LC3B, through interactions with Cav-1 and Fas, can regulate apoptosis.
Authors:
Zhi-Hua Chen; Hilaire C Lam; Yang Jin; Hong-Pyo Kim; Jiaofei Cao; Seon-Jin Lee; Emeka Ifedigbo; Harikrishnan Parameswaran; Stefan W Ryter; Augustine M K Choi
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2010-10-18
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  107     ISSN:  1091-6490     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-11-03     Completed Date:  2010-11-30     Revised Date:  2011-07-28    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  18880-5     Citation Subset:  IM    
Affiliation:
Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Antigens, CD95 / genetics,  metabolism
Apoptosis*
Autophagy / genetics
Caveolin 1 / genetics,  metabolism
Humans
Lung / metabolism*
Membrane Microdomains / genetics,  metabolism
Mice
Mice, Knockout
Microtubule-Associated Proteins / genetics,  metabolism*
Pulmonary Disease, Chronic Obstructive / chemically induced,  genetics,  metabolism*
Pulmonary Emphysema / chemically induced,  genetics,  metabolism*
Respiratory Mucosa / metabolism
Smoking / adverse effects*,  genetics,  metabolism
Grant Support
ID/Acronym/Agency:
R01-HL079904/HL/NHLBI NIH HHS; R01-HL090757/HL/NHLBI NIH HHS; R01-HL55330/HL/NHLBI NIH HHS; R01-HL60234/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Antigens, CD95; 0/CAV1 protein, human; 0/Cav1 protein, mouse; 0/Caveolin 1; 0/FAS protein, human; 0/Fas protein, mouse; 0/MAP1LC3 protein, mouse; 0/Microtubule-Associated Proteins; 0/light chain 3, human
Comments/Corrections

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