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Title: Mast cell chymase induces smooth muscle cell apoptosis by disrupting NF-{kappa}B-mediated survival signaling

Abstract

Chymase released from activated mast cells induces apoptosis of vascular smooth muscle cells (SMCs) in vitro by degrading the pericellular matrix component fibronectin, so causing disruption of focal adhesion complexes and Akt dephosphorylation, which are necessary for cell adhesion and survival. However, the molecular mechanisms of chymase-mediated apoptosis downstream of Akt have remained elusive. Here, we show by means of RT-PCR, Western blotting, EMSA, immunocytochemistry and confocal microscopy, that chymase induces SMC apoptosis by disrupting NF-{kappa}B-mediated survival signaling. Following chymase treatment, the translocation of active NF-{kappa}B/p65 to the nucleus was partly abolished and the amount of nuclear p65 was reduced. Pretreatment of SMCs with chymase also inhibited LPS- and IL-1{beta}-induced nuclear translocation of p65. The chymase-induced degradation of p65 was mediated by active caspases. Loss of NF-{kappa}B-mediated transactivation resulted in downregulation of bcl-2 mRNA and protein expression, leading to mitochondrial swelling and release of cytochrome c. The apoptotic process involved activation of both caspase 9 and caspase 8. The results reveal that, by disrupting the NF-{kappa}B-mediated survival-signaling pathway, activated chymase-secreting mast cells can mediate apoptosis of cultured arterial SMCs. Since activated mast cells colocalize with apoptotic SMCs in vulnerable areas of human atherosclerotic plaques, they may participate in the weakeningmore » and rupture of atherosclerotic plaques.« less

Authors:
 [1];  [1];  [2];  [1];  [3];  [1];  [4]
  1. Wihuri Research Institute, Kalliolinnantie 4, FI-00140 Helsinki (Finland)
  2. Bioengineering Department, University of Washington, Seattle, WA 98195 (United States)
  3. Department of Medicine, Helsinki University Central Hospital and Minerva Institute for Medical Research, Helsinki (Finland)
  4. Wihuri Research Institute, Kalliolinnantie 4, FI-00140 Helsinki (Finland). E-mail: ken.lindstedt@wri.fi
Publication Date:
OSTI Identifier:
20775366
Resource Type:
Journal Article
Resource Relation:
Journal Name: Experimental Cell Research; Journal Volume: 312; Journal Issue: 8; Other Information: DOI: 10.1016/j.yexcr.2005.12.033; PII: S0014-4827(05)00610-5; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; APOPTOSIS; BORON CHLORIDES; CELL NUCLEI; IN VITRO; MAST CELLS; MICROSCOPY; MUSCLES; POLYMERASE CHAIN REACTION; PROTEINS; RUPTURES; SWELLING; TRANSLOCATION

Citation Formats

Leskinen, Markus J., Heikkilae, Hanna M., Speer, Mei Y., Hakala, Jukka K., Laine, Mika, Kovanen, Petri T., and Lindstedt, Ken A. Mast cell chymase induces smooth muscle cell apoptosis by disrupting NF-{kappa}B-mediated survival signaling. United States: N. p., 2006. Web. doi:10.1016/j.yexcr.2005.12.033.
Leskinen, Markus J., Heikkilae, Hanna M., Speer, Mei Y., Hakala, Jukka K., Laine, Mika, Kovanen, Petri T., & Lindstedt, Ken A. Mast cell chymase induces smooth muscle cell apoptosis by disrupting NF-{kappa}B-mediated survival signaling. United States. doi:10.1016/j.yexcr.2005.12.033.
Leskinen, Markus J., Heikkilae, Hanna M., Speer, Mei Y., Hakala, Jukka K., Laine, Mika, Kovanen, Petri T., and Lindstedt, Ken A. Mon . "Mast cell chymase induces smooth muscle cell apoptosis by disrupting NF-{kappa}B-mediated survival signaling". United States. doi:10.1016/j.yexcr.2005.12.033.
@article{osti_20775366,
title = {Mast cell chymase induces smooth muscle cell apoptosis by disrupting NF-{kappa}B-mediated survival signaling},
author = {Leskinen, Markus J. and Heikkilae, Hanna M. and Speer, Mei Y. and Hakala, Jukka K. and Laine, Mika and Kovanen, Petri T. and Lindstedt, Ken A.},
abstractNote = {Chymase released from activated mast cells induces apoptosis of vascular smooth muscle cells (SMCs) in vitro by degrading the pericellular matrix component fibronectin, so causing disruption of focal adhesion complexes and Akt dephosphorylation, which are necessary for cell adhesion and survival. However, the molecular mechanisms of chymase-mediated apoptosis downstream of Akt have remained elusive. Here, we show by means of RT-PCR, Western blotting, EMSA, immunocytochemistry and confocal microscopy, that chymase induces SMC apoptosis by disrupting NF-{kappa}B-mediated survival signaling. Following chymase treatment, the translocation of active NF-{kappa}B/p65 to the nucleus was partly abolished and the amount of nuclear p65 was reduced. Pretreatment of SMCs with chymase also inhibited LPS- and IL-1{beta}-induced nuclear translocation of p65. The chymase-induced degradation of p65 was mediated by active caspases. Loss of NF-{kappa}B-mediated transactivation resulted in downregulation of bcl-2 mRNA and protein expression, leading to mitochondrial swelling and release of cytochrome c. The apoptotic process involved activation of both caspase 9 and caspase 8. The results reveal that, by disrupting the NF-{kappa}B-mediated survival-signaling pathway, activated chymase-secreting mast cells can mediate apoptosis of cultured arterial SMCs. Since activated mast cells colocalize with apoptotic SMCs in vulnerable areas of human atherosclerotic plaques, they may participate in the weakening and rupture of atherosclerotic plaques.},
doi = {10.1016/j.yexcr.2005.12.033},
journal = {Experimental Cell Research},
number = 8,
volume = 312,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2006},
month = {Mon May 01 00:00:00 EDT 2006}
}
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