Mitochondrial free calcium levels (Rhod-2 fluorescence) and ultrastructural alterations in neuronally differentiated PC12 cells during ceramide-dependent cell death.
J Comp Neurol
; 426(2): 297-315, 2000 Oct 16.
Article
em En
| MEDLINE
| ID: mdl-10982470
ABSTRACT
Mitochondrial free calcium levels measured by Rhod-2 fluorescence and ultrastructure were examined during cell death in nerve growth factor (NGF)-differentiated PC12 cells that were 1) exposed to C2-ceramide, 2) deprived of serum to induce endogenous ceramide production, or 3) treated with calcium ionophore A23187. Rhod-2 fluorescence in mitochondria and also in the nucleolus increased to a maximum within 3 hours after C2-ceramide treatment or serum withdrawal. In A23187-treated cells, Rhod-2 fluorescence remained at baseline levels. In all three models, enlargement of the endoplasmic reticulum was the first ultrastructural alteration, followed by mitochondrial shrinkage in ionophore-treated cells, but by mitochondrial swelling in the ceramide-dependent models, in which rupture of the outer mitochondrial membrane and unfolding of the inner membrane were frequently seen. Dihydro-C2-ceramide, which did not cause cell death, had no effect on cellular ultrastructure. NGF, which inhibits ceramide-dependent cell death, prevented the effects of serum deprivation on mitochondrial ultrastructure but not on endoplasmic reticulum morphology or Rhod-2 fluorescence. Nuclear shrinkage with loss of nuclear membrane integrity, characterized by nuclear pores, free or surrounded by electron-dense filaments, was a late event in ceramide-dependent cell death. Chromatin condensation and other morphological features associated with apoptosis were seen in only a few atypical cells. Ceramide-mediated cell death, therefore, did not involve classical apoptosis but was mediated by a reproducible series of events beginning in the endoplasmic reticulum, followed by the mitochondria, and then the nucleus. NGF-dependent cell death inhibition intervenes at the mitochondrial level, not by blocking the increase in Rhod-2 fluorescence but by preventing the ultrastructural changes that follow.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Esfingosina
/
Cálcio
/
Células PC12
/
Mitocôndrias
/
Neurônios
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Comp Neurol
Ano de publicação:
2000
Tipo de documento:
Article