Intracellular pH-dependent peroxynitrite-evoked synergistic death of glucose-deprived astrocytes

Chung Ju, Young J. Oh, Byung H. Han, Hee Sun Kim, Hyoung Chun Kim, Won-Ki Kim

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Previously, we reported that glucose-deprived astrocytes were highly vulnerable to peroxynitrite (ONOO -). Here we demonstrate that the increased vulnerability caused by glucose deprivation and ONOO - depends on intracellular pH. The ONOO - releasing reagent 3-morpholinosydnonimine (SIN-1) markedly induced the release of lactate dehydrogenase (LDH, the marker of cytotoxicity) in glucose-deprived astrocytes. Morphological studies and caspase activity assay showed that astrocytes treated together with glucose deprivation and ONOO - died mostly in a necrotic mode. Alkalinization of pH from 7.4 to 7.8 increased LDH release, whereas acidification from pH 7.4 to 7.0 decreased it. However, intracellular pH (pH i), not extracellular pH (pH e), appeared to play a critical role in the synergistic death. Thus, without a change in pH e (7.4) cytosolic acidification by a weak acid salt, sodium acetate, and a Na +/H + antiporter inhibitor, amiloride, reduced LDH release. In contrast, a weak base, NH 4Cl, and a Na +/H + antiporter stimulator, monensin, increased pH i and greatly enhanced LDH release. The augmented death was found to be due, in part, to the preceding decrease in the level of reduced glutathione, the ONOO - scavenger, and collapse of the mitochondrial transmembrane potential at alkaline pH.

Original languageEnglish
Pages (from-to)1160-1169
Number of pages10
JournalFree Radical Biology and Medicine
Volume37
Issue number8
DOIs
Publication statusPublished - 2004 Oct 15
Externally publishedYes

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Keywords

  • Astrocytes
  • Free radical
  • Mitochondrial permeability transition
  • Mitochondrial transmembrane permeability (Δψ )
  • Peroxynitrite (ONOO )
  • pH

ASJC Scopus subject areas

  • Medicine(all)
  • Toxicology
  • Clinical Biochemistry

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