title: Role of cytoskeleton network in anisosmotic volume changes of intact and permeabilized A549 cells.
abstract: Recently we found that cytoplasm of permeabilized mammalian cells behaves as a hydrogel displaying intrinsic osmosensitivity. This study examined the role of microfilaments and microtubules in the regulation of hydrogel osmosensitivity, volume-sensitive ion transporters, and their contribution to volume modulation of intact cells. We found that intact and digitonin-permeabilized A549 cells displayed similar rate of shrinkage triggered by hyperosmotic medium. It was significantly slowed-down in both cell preparations after disruption of actin microfilaments by cytochalasin B, suggesting that rapid water release by intact cytoplasmic hydrogel contributes to hyperosmotic shrinkage. In hyposmotic swelling experiments, disruption of microtubules by vinblastine attenuated the maximal amplitude of swelling in intact cells and completely abolished it in permeabilized cells. The swelling of intact cells also triggered ~10-fold elevation of furosemide-resistant (86)Rb+ (K+) permeability and the regulatory volume decrease (RVD), both of which were abolished by Ba2+. Interestingly, RVD and K+ permeability remained unaffected in cytocholasin/vinblastine treated cells demonstrating that cytoskeleton disruption has no direct impact on Ba2+-sensitive K+-channels involved in RVD. Our results show, for the first time, that the cytoskeleton network contributes directly to passive cell volume adjustments in anisosmotic media via the modulation of the water retained by the cytoplasmic hydrogel.
authors.affiliation: Research Centre, Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada; Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Platonova
authors.affiliation: Research Centre, Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada; Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia.
authors.forename: Olga
authors.initials: O
authors.lastname: Ponomarchuk
authors.affiliation: Research Centre, Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada.
authors.forename: Francis
authors.initials: F
authors.lastname: Boudreault
authors.affiliation: Tomsk State University, Tomsk, Russia.
authors.forename: Leonid V
authors.initials: LV
authors.lastname: Kapilevich
authors.affiliation: Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia.
authors.forename: Georgy V
authors.initials: GV
authors.lastname: Maksimov
authors.affiliation: Research Centre, Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada; Department of Medicine, University of Montreal, Montreal, QC, Canada. Electronic address: ryszard.grygorczyk@umontreal.ca.
authors.forename: Ryszard
authors.initials: R
authors.lastname: Grygorczyk
authors.affiliation: Research Centre, Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada; Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia; Tomsk State University, Tomsk, Russia. Electronic address: sergeinorlov@yandex.ru.
authors.forename: Sergei N
authors.initials: SN
authors.lastname: Orlov
mesh_terms: D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability / Q000187:drug effects*; D048429:Cell Size / Q000187:drug effects*; D003599:Cytoskeleton / Q000187:drug effects / Q000473:pathology*; D004072:Digitonin / Q000494:pharmacology*; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D009997:Osmotic Pressure
chemical_list: D004072:Digitonin
keywords: Hydrogel; K(+) channels; Microfilaments; Microtubules; Regulatory volume decrease