| Multiple ways to die: Delineation of the unfolded protein response and apoptosis induced by Surfactant Protein C BRICHOS mutants. | |
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MedLine Citation:
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PMID: 22016030 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Epithelial cell dysfunction is now recognized as an important mechanism in the pathogenesis of interstitial lung diseases. Surfactant Protein C (SP-C), an alveolar type II cell specific protein, has contributed to this concept with the observation that heterozygous expression of SFTPC gene mutations are associated with chronic interstitial lung disease. We have shown that transient expression of aggregation prone mutant SP-C isoforms (SP-C BRICHOS) destabilizes ER quality control mechanisms resulting in the intracellular accumulation of aggregating propeptide, inhibition of the ubiquitin/proteasome system, and activation of apoptosis. The goal of the present study was to define signaling pathways linking the unfolded protein response (UPR) and subsequent ER stress with intrinsic apoptosis events observed following mutant SP-C expression. In vitro expression of the SP-C BRICHOS mutant, SP-C(Δexon4), was used as a model system. Here we show stimulation of a broad ER stress response in both transfected A549 and HEK293 cells with activation of all 3 canonical sensing pathways, IRE1/XBP-1, ATF6, and PERK/eIF2α. SP-C(Δexon4) expression also resulted in activation of caspase 3 but failed to stimulate expression of the apoptosis mediating transcription factors ATF4/CHOP. However, inhibition of either caspase 4 or c-jun kinase (JNK) each blocked caspase 3 mediated cell death. Taken together, these results suggest that expression of SP-C BRICHOS mutants induce apoptosis via activation multiple CHOP independent but specific UPR signaling pathways, and provide new therapeutic targets for the amelioration of ER stress induced cytotoxicity observed in fibrotic lung remodeling. |
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Authors:
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Jean Ann Maguire; Surafel Mulugeta; Michael F Beers |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-10-13 |
Journal Detail:
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Title: The international journal of biochemistry & cell biology Volume: - ISSN: 1878-5875 ISO Abbreviation: - Publication Date: 2011 Oct |
Date Detail:
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Created Date: 2011-10-21 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9508482 Medline TA: Int J Biochem Cell Biol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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Copyright © 2011. Published by Elsevier Ltd. |
Affiliation:
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Surfactant Biology Laboratories, Pulmonary and Critical Care Division, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, United States. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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