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J Proteome Res. 2016 Sep 2;15(9):3188-95. doi: 10.1021/acs.jproteome.6b00413. Epub 2016 Jul 28.

Proteomic Profiling of Cardiomyocyte-Specific Cathepsin A Overexpression Links Cathepsin A to the Oxidative Stress Response.

Author information

1
Institute of Molecular Medicine and Cell Research, University of Freiburg , Stefan Meier Strasse 17, 79104 Freiburg, Germany.
2
Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes , 66424 Homburg/Saar, Germany.
3
Diabetes Division, Sanofi-Aventis Deutschland GmbH , 65926 Frankfurt, Germany.

Abstract

Cathepsin A (CTSA) is a lysosomal carboxypeptidase present at the cell surface and secreted outside the cell. Additionally, CTSA binds to β-galactosidase and neuraminidase 1 to protect them from degradation. CTSA has gained attention as a drug target for the treatment of cardiac hypertrophy and heart failure. Here, we investigated the impact of CTSA on the murine cardiac proteome in a mouse model of cardiomyocyte-specific human CTSA overexpression using liquid chromatography-tandem mass spectrometry in conjunction with an isotopic dimethyl labeling strategy. We identified up to 2000 proteins in each of three biological replicates. Statistical analysis by linear models for microarray data (limma) found >300 significantly affected proteins (moderated p-value ≤0.01), thus establishing CTSA as a key modulator of the cardiac proteome. CTSA strongly impaired the balance of the proteolytic system by upregulating several proteases such as cathepsin B, cathepsin D, and cathepsin Z while down-regulating numerous protease inhibitors. Moreover, cardiomyocyte-specific human CTSA overexpression strongly reduced the levels of numerous antioxidative stress proteins, i.e., peroxiredoxins and protein deglycase DJ-1. In vitro, using cultured rat cardiomyocytes, ectopic overexpression of CTSA resulted in accumulation of reactive oxygen species. Collectively, our proteomic and functional data strengthen an association of CTSA with the cellular oxidative stress response.

KEYWORDS:

mass spectrometry; oxidative stress; proteolysis; transgenic mouse

PMID:
27432266
DOI:
10.1021/acs.jproteome.6b00413
[Indexed for MEDLINE]

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