Uncoupling protein-2 overexpression inhibits mitochondrial death pathway in cardiomyocytes

Yasushi Teshima, Masaharu Akao, Steven P. Jones, Eduardo Marbán

Research output: Contribution to journalArticle

Abstract

Uncoupling proteins (UCPs) are located in the mitochondrial inner membrane and partially dissipate the transmembrane proton electrochemical gradient. UCP2 is expressed in various human and rodent tissues, including the heart, where its functional role is unknown. In the present study, we tested the hypothesis that UCP2 overexpression could protect cardiomyocytes from oxidative stress-induced cell death by reducing reactive oxygen species (ROS) production in mitochondria. Using an adenoviral vector containing human UCP2, we investigated the effects of UCP2 overexpression on the mitochondrial death pathway induced by oxidative stress (100 μmol/L H2O2) in cultured neonatal cardiomyocytes. UCP2 overexpression significantly suppressed markers of cell death, including TUNEL positivity, phosphatidylserine exposure, propidium iodide uptake, and caspase-3 cleavage. Furthermore, UCP2 remarkably prevented the catastrophic loss of mitochondrial inner membrane potential induced by H2O2, which is a critical early event in cell death. Ca2+ overload and the production of ROS in mitochondria, both of which contribute to mitochondrial inner membrane potential loss, were dramatically attenuated by UCP2 overexpression. Thus, overexpression of UCP2 attenuates ROS generation and prevents mitochondrial Ca2+ overload, revealing a novel mechanism of cardioprotection.

Original languageEnglish (US)
Pages (from-to)192-200
Number of pages9
JournalCirculation Research
Volume93
Issue number3
DOIs
StatePublished - Aug 8 2003

Keywords

  • Calcium
  • Heart
  • Membrane potential
  • Mitochondria
  • Reactive oxygen species

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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