title: Swelling rather than shrinkage precedes apoptosis in serum-deprived vascular smooth muscle cells.
abstract: Contrasting cell volume behaviours (swelling vs. shrinkage) are considered as criteria to distinguish necrosis from apoptosis. In this study, we employed a time-lapse, dual-image surface reconstruction technique to assess the volume of single vascular smooth muscle cells transfected with E1A-adenoviral protein (E1A-VSMC) and undergoing rapid apoptosis in the absence of growth factors or in the presence of staurosporine. After 30- to 60-min lag-phase, serum-deprived E1A-VSMC volume was increased by ~40%, which preceded maximal increments of caspase-3 activity and chromatin cleavage. Swollen cells underwent rapid apoptotic collapse, documented by plasma membrane budding, and terminated in 10-15 min by the formation of numerous apoptotic bodies. Suppression of apoptosis by inhibition of Na(+),K(+)-ATPase and activation of cAMP signalling with ouabain and forskolin, respectively, completely abolished the swelling of serum-deprived E1A-VSMC. In contrast to serum deprivation, apoptotic collapse of staurosporine-treated E1A-VSMC preceded attenuation of their volume by ~30%. Neither transient hyposmotic swelling nor isosmtotic shrinkage triggered apoptosis. Our results show that cell shrinkage can not be considered as ubiquitous hallmark of apoptosis. The involvement of stimulus-specific cell volume perturbations in initiation and progression of apoptosis in vascular smooth muscle cells should be examined further.
authors.affiliation: Research Centre, Centre hospitalier de l'Université de Montréal (CRCHUM), Technopôle Angus, Montreal, QC, Canada.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Platonova
authors.forename: Svetlana V
authors.initials: SV
authors.lastname: Koltsova
authors.forename: Pavel
authors.initials: P
authors.lastname: Hamet
authors.forename: Ryszard
authors.initials: R
authors.lastname: Grygorczyk
authors.forename: Sergei N
authors.initials: SN
authors.lastname: Orlov
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D048429:Cell Size; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D016895:Culture Media, Serum-Free; D053837:DNA Cleavage; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000502:physiology*; D009997:Osmotic Pressure; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D059010:Single-Cell Analysis; D019311:Staurosporine / Q000494:pharmacology; D059008:Time-Lapse Imaging
chemical_list: D002843:Chromatin; D016895:Culture Media, Serum-Free; D005576:Colforsin; D010042:Ouabain; C505410:Casp3 protein, rat; D053148:Caspase 3; D019311:Staurosporine