title: Adaptive responses of cell hydration to a low temperature arrest.
abstract: Slow cooling leads to a passive dehydration of cells, whereas rehydration during warming reflects the active regain of functionality. The ability to modulate such an energy demanding process could be instrumental in optimizing the cryo-arrest of living systems. In the present study, various levels of hypertonic stress were used to disturb the water content of cells and to define the energy profiles of aquaporins and (Na(+) conducting) cation channels during rehydration. Na(+) import was found to be the rate-limiting step in water restoration, whereas aquaporins merely played a permissive role. Indeed, regulated Na(+) import was increased 2-fold following cryo-arrests, thus facilitating the osmotic rehydration of cells. Freezing temperatures increased cell viscosity with a remarkable hysteresis and viscosity was a trigger of cation channels. The peptide hormone vasopressin was a further activator of channels, increasing the viability of post-cryo cells considerably. Hence, the hormone opens the path for a novel class of cryo-protectants with an intrinsic biological activity.
authors.affiliation: Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Dortmund, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Christmann
authors.affiliation: Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Dortmund, Germany.
authors.forename: Lale
authors.initials: L
authors.lastname: Azer
authors.affiliation: Fraunhofer Institute for Biomedical Engineering, St Ingbert, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Dörr
authors.affiliation: Fraunhofer Institute for Biomedical Engineering, St Ingbert, Germany.
authors.forename: Günter R
authors.initials: GR
authors.lastname: Fuhr
authors.affiliation: Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Dortmund, Germany.
authors.forename: Philippe I H
authors.initials: PI
authors.lastname: Bastiaens
authors.affiliation: Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Dortmund, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Wehner
mesh_terms: D000222:Adaptation, Physiological; D020346:Aquaporins / Q000378:metabolism; D059447:Cell Cycle Checkpoints; D002470:Cell Survival / Q000187:drug effects; D058639:Cold-Shock Response; D005615:Freezing; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D009997:Osmotic Pressure; D014667:Vasopressins / Q000494:pharmacology; D014783:Viscosity; D061566:Voltage-Gated Sodium Channels / Q000378:metabolism
chemical_list: D020346:Aquaporins; D061566:Voltage-Gated Sodium Channels; D014667:Vasopressins