Mitochondrial fission in endothelial cells after simulated ischemia/reperfusion: role of nitric oxide and reactive oxygen species

Free Radic Biol Med. 2012 Jan 15;52(2):348-56. doi: 10.1016/j.freeradbiomed.2011.10.491. Epub 2011 Nov 6.

Abstract

Ischemia (I)/reperfusion (RP)-induced endothelial cell (EC) injury is thought to be due to mitochondrial reactive oxygen species (mtROS) production. MtROS have been implicated in mitochondrial fission. We determined whether cultured EC exposure to simulated I/RP causes morphological changes in the mitochondrial network and the mechanisms behind those changes. Because shear stress results in nitric oxide (NO)-mediated endothelial mtROS generation, we simulated I/RP as hypoxia (H) followed by oxygenated flow over the ECs (shear stress of 10dyn/cm(2)). By exposing ECs to shear stress, H, H/reoxygenation (RO), or simulated I/RP and employing MitoTracker staining, we assessed the differential effects of changes in mechanical forces and/or O(2) levels on the mitochondrial network. Static or sheared ECs maintained their mitochondrial network. H- or H/RO-exposed ECs underwent changes, but mitochondrial fission was significantly less compared to that in ECs exposed to I/RP. I/RP-induced fission was partially inhibited by antioxidants, a NO synthase inhibitor, or an inhibitor of the fission protein dynamin-related protein 1 (Drp1) and was accompanied by Drp1 oligomerization and phosphorylation (Ser616). Hence, shear-induced NO, ROS (including mtROS), and Drp1 activation are responsible for mitochondrial fission in I/RP-exposed ECs, and excessive fission may be an underlying cause of EC dysfunction in postischemic hearts.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcysteine / pharmacology
  • Antioxidants / pharmacology
  • Cell Hypoxia
  • Cells, Cultured
  • Dynamins
  • GTP Phosphohydrolases / metabolism
  • Human Umbilical Vein Endothelial Cells / drug effects
  • Human Umbilical Vein Endothelial Cells / metabolism*
  • Humans
  • Membrane Potential, Mitochondrial
  • Microtubule-Associated Proteins / metabolism
  • Mitochondria / drug effects
  • Mitochondria / metabolism*
  • Mitochondrial Proteins / metabolism
  • NG-Nitroarginine Methyl Ester / pharmacology
  • Nitric Oxide / metabolism*
  • Nitric Oxide Synthase / antagonists & inhibitors
  • Nitric Oxide Synthase / metabolism
  • Organelle Shape
  • Oxaloacetic Acid / pharmacology
  • Phosphorylation
  • Protein Multimerization
  • Reperfusion Injury / metabolism*
  • Shear Strength
  • Stress, Mechanical
  • Superoxides / metabolism*

Substances

  • Antioxidants
  • Microtubule-Associated Proteins
  • Mitochondrial Proteins
  • Superoxides
  • Oxaloacetic Acid
  • Nitric Oxide
  • Nitric Oxide Synthase
  • GTP Phosphohydrolases
  • DNM1L protein, human
  • Dynamins
  • NG-Nitroarginine Methyl Ester
  • Acetylcysteine