Doxorubicin (DOX) is an effective anti-cancer agent. However, DOX treatment increases patient susceptibility to dilated cardiomyopathy. DOX predisposes cardiomyocytes to insult by suppressing mitochondrial energy metabolism, altering calcium flux, and disrupting proteolysis and proteostasis. Prior studies have assessed the role of macroautophagy in DOX cardiotoxicity; however, limited studies have examined whether DOX mediates cardiac injury through dysfunctions in inter- and/or intra-lysosomal signaling events. Lysosomal signaling and function is governed by transcription factor EB (TFEB). In the present study, we hypothesized that DOX caused myocyte injury by impairing lysosomal function and signaling through negative regulation of TFEB. Indeed, we found that DOX repressed cellular TFEB expression, which was associated with impaired cathepsin proteolytic activity across in vivo, ex vivo, and in vitro models of DOX cardiotoxicity. Furthermore, we observed that loss of TFEB was associated with reduction in macroautophagy protein expression, inhibition of autophagic flux, impairments in lysosomal cathepsin B activity, and activation of cell death. Restoration and/or activation of TFEB in DOX-treated cardiomyocytes prevented DOX-induced suppression of cathepsin B activity, reduced DOX-mediated reactive oxygen species (ROS) overproduction, attenuated activation of caspase-3, and improved cellular viability. Collectively, loss of TFEB inhibits lysosomal autophagy, rendering cardiomyocytes susceptible to DOX-induced proteotoxicity and injury. Our data reveal a novel mechanism wherein DOX primes cardiomyocytes for cell death by depleting cellular TFEB.
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November 2016
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From untargeted plasma metabolomics from carriers affected with the FMR1 premutation and control subjects, putative target proteins were identified which were used as input data to build a protein-protein interaction network. Please see pp. 3871–3888 for further information. Image provided by C. Guilivi.
Research Article|
October 27 2016
Doxorubicin impairs cardiomyocyte viability by suppressing transcription factor EB expression and disrupting autophagy
Jordan J. Bartlett;
Jordan J. Bartlett
*
1Faculty of Medicine, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
2Dalhousie Medicine New Brunswick, Saint John, NB, Canada
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Purvi C. Trivedi;
Purvi C. Trivedi
*
1Faculty of Medicine, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
2Dalhousie Medicine New Brunswick, Saint John, NB, Canada
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Pollen Yeung;
Pollen Yeung
3College of Pharmacy and Department of Medicine (Cardiology), Dalhousie University, Halifax, NS, Canada
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Petra C. Kienesberger;
Petra C. Kienesberger
1Faculty of Medicine, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
2Dalhousie Medicine New Brunswick, Saint John, NB, Canada
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Thomas Pulinilkunnil
Thomas Pulinilkunnil
1Faculty of Medicine, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
2Dalhousie Medicine New Brunswick, Saint John, NB, Canada
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Biochem J (2016) 473 (21): 3769–3789.
Article history
Received:
April 22 2016
Revision Received:
July 20 2016
Accepted:
August 03 2016
Accepted Manuscript online:
August 03 2016
Citation
Jordan J. Bartlett, Purvi C. Trivedi, Pollen Yeung, Petra C. Kienesberger, Thomas Pulinilkunnil; Doxorubicin impairs cardiomyocyte viability by suppressing transcription factor EB expression and disrupting autophagy. Biochem J 1 November 2016; 473 (21): 3769–3789. doi: https://doi.org/10.1042/BCJ20160385
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