TY - JOUR
T1 - Role of cytoskeleton network in anisosmotic volume changes of intact and permeabilized A549 cells
AU - Platonova, Alexandra
AU - Ponomarchuk, Olga
AU - Boudreault, Francis
AU - Kapilevich, Leonid V.
AU - Maksimov, Georgy V.
AU - Grygorczyk, Ryszard
AU - Orlov, Sergei N.
PY - 2015/7/23
Y1 - 2015/7/23
N2 - 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 86Rb+ (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.
AB - 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 86Rb+ (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.
KW - Hydrogel
KW - K<sup>+</sup> channels
KW - Microfilaments
KW - Microtubules
KW - Regulatory volume decrease
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UR - http://www.scopus.com/inward/citedby.url?scp=84937485423&partnerID=8YFLogxK
U2 - 10.1016/j.bbamem.2015.07.005
DO - 10.1016/j.bbamem.2015.07.005
M3 - Article
C2 - 26171817
AN - SCOPUS:84937485423
VL - 1848
SP - 2337
EP - 2343
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
SN - 0005-2736
IS - 10
ER -