Gliotoxin induces apoptosis in cultured macrophages via production of reactive oxygen species and cytochrome c release without mitochondrial depolarization

Free Radic Res. 2001 Jul;35(1):1-10. doi: 10.1080/10715760100300541.


The cytotoxicity and its underlying mechanisms induced by gliotoxin (GT), an immunosuppressive agent, in macrophages are poorly understood. We report here that GT induced a rapid apoptosis (DNA fragmentation and hypodiploid nuclei obtained within 4 hrs of treatment) in murine macrophages PU5-1.8 in a dose-dependent and cell cycle-independent manner. The GT-induced apoptosis was suppressed by z-Asp, z-VAD-fmk and antioxidants suggesting that production of reactive oxygen species (ROS) and activation of caspases were important in this process. Also, release of cytochrome c from mitochondria was found to be an early event (within 1 hr) after addition of GT (250 ng/ml) and its presence in the cytosol was sufficient to elicit apoptosis. Interestingly, the release of cytochrome c was not accompanied by a reduction in the mitochondrial membrane potential (psi m) as determined by several psi m-sensitive fluorescent indicators. Taken together, our results indicate that GT is a potent apoptotic agent in PU5-1.8 cells and the loss of psi m is not a universal early marker for apoptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / pharmacology
  • Apoptosis / drug effects*
  • Blotting, Western
  • Cell Cycle / drug effects
  • Cell Line
  • Cytochrome c Group / metabolism*
  • Ethidium / analogs & derivatives*
  • Flow Cytometry
  • Gliotoxin / pharmacology*
  • Hydrogen Peroxide
  • Immunosuppressive Agents / pharmacology*
  • Macrophages / drug effects*
  • Macrophages / metabolism
  • Membrane Potentials / drug effects
  • Mice
  • Mice, Inbred BALB C
  • Mitochondria / drug effects
  • Mitochondria / metabolism*
  • Reactive Oxygen Species / metabolism*
  • Scopoletin


  • Antioxidants
  • Cytochrome c Group
  • Immunosuppressive Agents
  • Reactive Oxygen Species
  • dihydroethidium
  • Gliotoxin
  • Hydrogen Peroxide
  • Ethidium
  • Scopoletin