Schrammel A, Mussbacher M, Winkler S, Haemmerle G, Stessel H, Wölkart G, Zechner R, Mayer B. Cardiac oxidative stress in a mouse model of neutral lipid storage disease.
Biochim Biophys Acta Mol Cell Biol Lipids 2013;
1831:1600-8. [PMID:
23867907 PMCID:
PMC3795454 DOI:
10.1016/j.bbalip.2013.07.004]
[Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/19/2013] [Accepted: 07/08/2013] [Indexed: 12/11/2022]
Abstract
Cardiac oxidative stress has been implicated in the pathogenesis of hypertrophy, cardiomyopathy and heart failure. Systemic deletion of the gene encoding adipose triglyceride lipase (ATGL), the enzyme that catalyzes the rate-limiting step of triglyceride lipolysis, results in a phenotype characterized by severe steatotic cardiac dysfunction. The objective of the present study was to investigate a potential role of oxidative stress in cardiac ATGL deficiency. Hearts of mice with global ATGL knockout were compared to those of mice with cardiomyocyte-restricted overexpression of ATGL and to those of wildtype littermates. Our results demonstrate that oxidative stress, measured as lucigenin chemiluminescence, was increased ~ 6-fold in ATGL-deficient hearts. In parallel, cytosolic NADPH oxidase subunits p67phox and p47phox were upregulated 4–5-fold at the protein level. Moreover, a prominent upregulation of different inflammatory markers (tumor necrosis factor α, monocyte chemotactant protein-1, interleukin 6, and galectin-3) was observed in those hearts. Both the oxidative and inflammatory responses were abolished upon cardiomyocyte-restricted overexpression of ATGL. Investigating the effect of oxidative and inflammatory stress on nitric oxide/cGMP signal transduction we observed a ~ 2.5-fold upregulation of soluble guanylate cyclase activity and a ~ 2-fold increase in cardiac tetrahydrobiopterin levels. Systemic treatment of ATGL-deficient mice with the superoxide dismutase mimetic Mn(III)tetrakis (4-benzoic acid) porphyrin did not ameliorate but rather aggravated cardiac oxidative stress. Our data suggest that oxidative and inflammatory stress seems involved in lipotoxic heart disease. Upregulation of soluble guanylate cyclase and cardiac tetrahydrobiopterin might be regarded as counterregulatory mechanisms in cardiac ATGL deficiency.
ATGL(−/−) mice suffer from severe cardiac oxidative stress originating from upregulation of NOX2-dependent NADPH oxidase.
Inflammation markers TNFα, MCP-1, IL-6, and Mac-2 are increased in cardiac ATGL deficiency.
Activity of sGC and cardiac BH4 levels are elevated in ATGL(−/−) hearts.
Systemic treatment of ATGL(−/−) mice with the SOD mimetic MnTBAP did not ameliorate oxidative stress.
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