title: Diclofenac induces proteasome and mitochondrial dysfunction in murine cardiomyocytes and hearts.
abstract: BACKGROUND
  One of the most common nonsteroidal anti-inflammatory drugs (NSAIDs) used worldwide, diclofenac (DIC), has been linked to increased risk of cardiovascular disease (CVD). The molecular mechanism(s) by which DIC causes CVD is unknown.
  
  
  METHODS
  Proteasome activities were studied in hearts, livers, and kidneys from male Swiss Webster mice treated with either 100mg/kg DIC for 18h (acute treatment) or 10mg/kg DIC for 28days (chronic treatment). Cultured H9c2 cells and neonatal cardiomyocytes were also treated with different concentrations of DIC and proteasome function, cell death and ROS generation studied. Isolated mouse heart mitochondria were utilized to determine the effect of DIC on various electron transport chain complex activities.
  
  
  RESULTS
  DIC significantly inhibited the chymotrypsin-like proteasome activity in rat cardiac H9c2 cells, murine neonatal cardiomyocytes, and mouse hearts, but did not affect proteasome subunit expression levels. Proteasome activity was also affected in liver and kidney tissues from DIC treated animals. The levels of polyubiquitinated proteins increased in hearts from DIC treated mice. Importantly, the levels of oxidized proteins increased while the β5i immunoproteasome activity decreased in hearts from DIC treated mice. DIC increased ROS production and cell death in H9c2 cells and neonatal cardiomyocytes while the cardioprotective NSAID, aspirin, had no effect on ROS levels or cell viability. DIC inhibited mitochondrial Complex III, a major source of ROS, and impaired mitochondrial membrane potential suggesting that mitochondria are the major sites of ROS generation.
  
  
  CONCLUSIONS
  These results suggest that DIC induces cardiotoxicity by a ROS dependent mechanism involving mitochondrial and proteasome dysfunction.
authors: Department of Neurobiology, Physiology and Behavior, University of California, Davis, CA 95616, United States.
authors: Rajeshwary
authors: R
authors: Ghosh
authors: Department of Entomology and Nematology and Comprehensive Cancer Center, University of California, Davis, CA 95616, United States.
authors: Sumanta K
authors: SK
authors: Goswami
authors: Department of Neurobiology, Physiology and Behavior, University of California, Davis, CA 95616, United States.
authors: Luis Felipe B B
authors: LFBB
authors: Feitoza
authors: Department of Entomology and Nematology and Comprehensive Cancer Center, University of California, Davis, CA 95616, United States.
authors: Bruce
authors: B
authors: Hammock
authors: Department of Neurobiology, Physiology and Behavior, Department of Physiology and Membrane Biology, University of California, Davis, CA 95616, United States. Electronic address: avgomes@ucdavis.edu.
authors: Aldrin V
authors: AV
authors: Gomes
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D066126:Cardiotoxicity / Q000209:etiology / Q000378:metabolism; D002478:Cells, Cultured; D004008:Diclofenac / Q000494:pharmacology*; D051379:Mice; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D046988:Proteasome Endopeptidase Complex / Q000187:drug effects / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D017382:Reactive Oxygen Species; D004008:Diclofenac; D046988:Proteasome Endopeptidase Complex
keywords: Cardiac cells; Cell death; Diclofenac; Mitochondria; Proteasome; Reactive oxygen species