The mitochondrial permeability transition mediates both necrotic and apoptotic death of hepatocytes exposed to Br-A23187

Ting Qian, Brian Herman, John J. Lemasters

Research output: Contribution to journalArticlepeer-review

135 Scopus citations

Abstract

A23187 and related Ca2+ ionophores are widely used to study Ca2+- dependent cell injury. Here, using laser scanning confocal microscopy and parameter-indicating fluorophores, we investigated the role of the mitochondrial permeability transition (MPT) in Br-A23187 toxicity to cultured rat hepatocytes. After 10 μM Br-A23187, over 60% of hepatocytes lost viability within 1 h. This necrotic cell killing was preceded by increased mitochondrial free Ca2+, mitochondrial depolarization, and onset of the MPT. Cyclosporin A (CsA), a blocker of the permeability transition pore, prevented the MPT and cell killing but had no effect on increased mitochondrial free Ca2+ and depolarization after Br-A23187. To determine whether Br-A23187-induced cell killing was linked to loss of cellular ATP supply, hepatocytes were incubated with fructose and oligomycin, a source of glycolytic ATP and an inhibitor of the uncoupler-stimulated mitochondrial ATPase, respectively. Fructose plus oligomycin prevented cell killing after Br-A23187 but not the MPT. When fructose plus oligomycin prevented necrotic cell killing, apoptosis developed after 10 h. When cells were treated additionally with CsA, these apoptotic changes were prevented. In conclusion, the MPT mediates Br-A23187 cytotoxicity. Acutely, the MPT causes mitochondrial uncoupling and profound ATP depletion, which leads to necrotic cell death. However, when glycolytic ATP generation is available, the MPT induces apoptosis. CsA blocks the MPT and prevents both necrotic and apoptotic cell killing after Br-A23187.

Original languageEnglish (US)
Pages (from-to)117-125
Number of pages9
JournalToxicology and Applied Pharmacology
Volume154
Issue number2
DOIs
StatePublished - Jan 15 1999

Bibliographical note

Funding Information:
1This work was supported, in part, by Grants AG60721, DK37034, and AA11606 from National Institutes of Health. 2Present address: Confocal Facility, Box 248, The Rockefeller University, 1230 York Ave., New York, NY 10021. 3Present address: Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, Texas 78284-7762. 4To whom correspondence should be addressed.

Keywords

  • Apoptosis
  • Calcium ionophore
  • Confocal microscopy
  • Mitochondrial permeability transition
  • Necrosis

Fingerprint

Dive into the research topics of 'The mitochondrial permeability transition mediates both necrotic and apoptotic death of hepatocytes exposed to Br-A23187'. Together they form a unique fingerprint.

Cite this