Stage-Specific Changes in the Water, Na+, Cl- and K+ Contents of Organelles during Apoptosis, Demonstrated by a Targeted Cryo Correlative Analytical Approach.
Fiche publication
Date publication
janvier 2016
Journal
PloS one
Auteurs
Membres identifiés du Cancéropôle Est :
Pr MICHEL Jean, Pr PLOTON Dominique, Dr TERRYN Christine
Tous les auteurs :
Nolin F, Michel J, Wortham L, Tchelidze P, Banchet V, Lalun N, Terryn C, Ploton D
Lien Pubmed
Résumé
Many studies have demonstrated changes in the levels of several ions during apoptosis, but a few recent studies have reported conflicting results concerning the changes in water content in apoptotic cells. We used a correlative light and cryo-scanning transmission electron microscopy method to quantify water and ion/element contents simultaneously at a nanoscale resolution in the various compartments of cells, from the onset to the end of apoptosis. We used stably transfected HeLa cells producing H2B-GFP to identify the stages of apoptosis in cells and for a targeted elemental analysis within condensed chromatin, nucleoplasm, mitochondria and the cytosol. We found that the compartments of apoptotic cells contained, on average, 10% more water than control cells. During mitochondrial outer membrane permeabilization, we observed a strong increase in the Na+ and Cl- contents of the mitochondria and a strong decrease in mitochondrial K+ content. During the first step in apoptotic volume decrease (AVD), Na+ and Cl- levels decreased in all cell compartments, but remained higher than those in control cells. Conversely, during the second step of AVD, Na+ and Cl- levels increased considerably in the nucleus and mitochondria. During these two steps of AVD, K+ content decreased steadily in all cell compartments. We also determined in vivo ion status during caspase-3 activity and chromatin condensation. Finally, we found that actinomycin D-tolerant cells had water and K+ contents similar to those of cells entering apoptosis but lower Na+ and Cl- contents than both cells entering apoptosis and control cells.
Mots clés
Anions, analysis, Apoptosis, drug effects, Caspase 3, analysis, Cations, analysis, Cell Membrane Permeability, Cell Size, Chlorides, analysis, Cryoelectron Microscopy, methods, Cytochromes c, analysis, Dactinomycin, pharmacology, HeLa Cells, Humans, Image Processing, Computer-Assisted, Microscopy, Electron, Scanning, methods, Mitochondria, chemistry, Mitochondrial Membranes, Nanotechnology, methods, Organelles, chemistry, Poly Adenosine Diphosphate Ribose, analysis, Potassium, analysis, Sodium, analysis, Spectrometry, X-Ray Emission, methods, Time-Lapse Imaging, methods, Water, analysis
Référence
PLoS ONE. 2016 ;11(2):e0148727