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Subcellular heterogeneity of mitochondrial membrane potential: Relationship with organelle distribution and intercellular contacts in normal, hypoxic and apoptotic cells

1999; The Company of Biologists; Volume: 112; Issue: 7 Linguagem: Inglês

10.1242/jcs.112.7.1077

1477-9137

Giacomo Diaz, Maria Dolores Setzu, Andrea Zucca, Raffaella Isola, Andrea Diana, Roberto Murru, Valeria Sogos, Fulvia Gremo,

Infectious Encephalopathies and Encephalitis

ABSTRACT The subcellular heterogeneity of mitochondrial membrane potential (mΔΨ) was investigated in confluent and sub-confluent cultures of four cell types (human astrocytes, HEp-2, MDCK and Vero cells) in normal growth conditions, hypoxia and apoptosis. The distribution of high-polarized mitochondria, detected by the potential-sensitive probe JC-1, was found to depend on: (1) the proximity to the cell edge; (2) the local absence of cell-cell contacts; and (3) the local absence of acidic vesicles. Both hypoxia and apoptosis produced a general mΔΨ increase with different redistributions of high-polarized mitochondria. Hypoxic cells maintained high-polarized mitochondria for over 24 hours, until cells underwent necrosis. On the other hand, apoptotic cells showed an unexpected convergence of high-polarized mitochondria into an extremely packed mass at one side of the nucleus, in a stage preceding nuclear condensation, but correlated to the retraction of cell-cell contacts.