Adenoviral gene transfer of activated phosphatidylinositol 3'-kinase and Akt inhibits apoptosis of hypoxic cardiomyocytes in vitro

Takashi Matsui, Ling Li, Federica Del Monte, Yasuhisa Fukui, Thomas F. Franke, Roger J. Hajjar, Anthony Rosenzweig

Research output: Contribution to journalArticlepeer-review

337 Scopus citations

Abstract

Background - The intracellular signaling pathways that control cardiomyocyte apoptosis have not been fully defined. Because insulin-like growth factor-1 (IGF-1) prevents cardiomyocyte apoptosis, we examined the role of its downstream signaling molecules in an in vitro model of hypoxia- induced cardiomyocyte apoptosis. Methods and Results - Treatment of rat neonatal cardiomyocytes with IGF-1 increased activity of both phosphatidylinositol 3' (PI 3)-kinase and its downstream target, Akt (also known as protein kinase B or PKB). Cardiomyocytes were subjected to hypoxia for 24 hours, and apoptosis was assessed by DNA laddering, TUNEL staining, and ELISA for histone-associated DNA fragments. IGF-1 treatment (100 nmol/L) reduced cardiomyocyte apoptosis, and this effect was inhibited by simultaneous treatment with a PI 3-kinase inhibitor. Cardiomyocytes were infected with either a control adenovirus (Ad.EGFP) or adenoviruses carrying constitutively active forms of PI 3-kinase (Ad.BD110) or Akt (Ad.myr-Akt-HA). Ad.BD110 significantly inhibited apoptosis of hypoxic cardiomyocytes compared with Ad:EGFP (61.0±4.6% less DNA fragmentation than in Ad.EGFP-infected cells, P<0.0001). Ad.myr-Akt-HA even more dramatically inhibited apoptosis of hypoxic cardiomyocytes (90.9±1.4% less DNA fragmentation than in controls, P<0.0001). Conclusions - IGF-1 activates PI 3-kinase and Akt in cardiomyocytes. Activated PI 3-kinase and Akt are each sufficient to protect hypoxic cardiomyocytes against apoptosis in vitro. Adenoviral gene transfer provides a useful tool for investigating the role of these signaling pathways in cardiomyocyte apoptosis.

Original languageEnglish
Pages (from-to)2373-2379
Number of pages7
JournalCirculation
Volume100
Issue number23
DOIs
StatePublished - 7 Dec 1999
Externally publishedYes

Keywords

  • Growth substances
  • Kinase
  • Signal transduction
  • Viruses

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