Subcellular heterogeneity of mitochondrial membrane potential: relationship with organelle distribution and intercellular contacts in normal, hypoxic and apoptotic cells.
The subcellular heterogeneity of mitochondrial membrane potential (mDelta psi) 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 mDelta psi 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.
Diaz
G
G
Departments of Cytomorphology and Medical Sciences, University of Cagliari, Italy. gdiaz@unica.it
Setzu
M D
MD
Zucca
A
A
Isola
R
R
Diana
A
A
Murru
R
R
Sogos
V
V
Gremo
F
F
D000818:Animals; D017209:Apoptosis; D001253:Astrocytes / Q000378:metabolism; D002166:Camptothecin / Q000494:pharmacology; D002460:Cell Line; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018698:Glutamic Acid / Q000494:pharmacology; D006801:Humans; D000860:Hypoxia; D007425:Intracellular Membranes / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology*; D008928:Mitochondria / Q000502:physiology*; D015388:Organelles / Q000502:physiology*; D012965:Sodium Chloride / Q000378:metabolism; D014709:Vero Cells
D004791:Enzyme Inhibitors; D018698:Glutamic Acid; D012965:Sodium Chloride; D002166:Camptothecin