Glutathione homeostasis in ventricular myocytes from rat hearts with chronic myocardial infarction

Shumin Li, Ming Qi Zheng, George J. Rozanski

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Abstract

The ubiquitous tripeptide glutathione (GSH) is an essential factor in many biological processes, thus its depletion has a major impact on cell function and survival. In this study, we examined regulation of GSH in cardiomyocytes under chronic oxidative stress elicited by myocardial infarction (MI). Cardiac dysfunction was induced in rats by coronary artery ligation, and experiments were conducted in myocytes isolated from non-infarcted left ventricle and septum after 6-8 weeks. Fluorescence microscopy studies using the probe monochlorobimane showed that [GSH] in myocytes from post-MI hearts was 42% less than in sham control hearts (P < 0.05). However, depleted GSH levels were normalized after 5-6 h by an insulin mimetic (bis-peroxovanadium-1,10- phenanthroline, bpV(phen); 10 μmol l-1) or by exogenous pyruvate (5 mmol l-1). The increase in [GSH] by bpV(phen) was partly inhibited by buthionine sulphoximine (BSO; 50 μmol l-1), a blocker of GSH synthesis, and by 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU; 100 μmol l-1), an inhibitor of glutathione disulphide reductase. By comparison, the effect of pyruvate was not altered by BSO but was completely blocked by BCNU. Studies using inhibitors of signalling cascades indicated that upregulation of [GSH] by bpV(phen) in myocytes from post-MI hearts was mediated by mitogen activated protein kinase/extracellular signal-regulated kinase kinase 1/2 and p38 mitogen-activated protein kinase but not by phosphatidylinositol 3-kinase. The effect of pyruvate was not altered by any kinase inhibitor tested. In cells loaded with the probe TEMPO-9-AC to monitor superoxide anion, baseline fluorescence was 2.3-fold greater in post-MI myocytes than in sham control myocytes (P < 0.05) and was markedly decreased by diphenyleneiodonium (30 μmol l-1), an inhibitor of NADPH oxidase, exogenous GSH (10 mmol l-1) or bpV(phen). In parallel studies, [GSH] in post-MI myocytes was also normalized by diphenyleneiodonium or exogenous GSH. These data show that GSH is differentially regulated by receptor tyrosine kinase-dependent and -independent agonists that maintain functional GSH levels necessary to neutralize excess generation of reactive oxygen species in the failing heart.

Original languageEnglish (US)
Pages (from-to)815-824
Number of pages10
JournalExperimental Physiology
Volume94
Issue number7
DOIs
StatePublished - Jul 2009

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Muscle Cells
Glutathione
Homeostasis
Myocardial Infarction
Carmustine
Phenanthrolines
Pyruvic Acid
Phosphotransferases
Phosphatidylinositol 3-Kinase
Buthionine Sulfoximine
Biological Phenomena
Glutathione Reductase
Extracellular Signal-Regulated MAP Kinases
Receptor Protein-Tyrosine Kinases
p38 Mitogen-Activated Protein Kinases
Mitogen-Activated Protein Kinases
Fluorescence Microscopy
Cardiac Myocytes
Superoxides
Heart Ventricles

ASJC Scopus subject areas

  • Physiology
  • Nutrition and Dietetics
  • Physiology (medical)

Cite this

Glutathione homeostasis in ventricular myocytes from rat hearts with chronic myocardial infarction. / Li, Shumin; Zheng, Ming Qi; Rozanski, George J.

In: Experimental Physiology, Vol. 94, No. 7, 07.2009, p. 815-824.

Research output: Contribution to journalArticle

Li, Shumin ; Zheng, Ming Qi ; Rozanski, George J. / Glutathione homeostasis in ventricular myocytes from rat hearts with chronic myocardial infarction. In: Experimental Physiology. 2009 ; Vol. 94, No. 7. pp. 815-824.
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