title: Membrane disorder and phospholipid scrambling in electropermeabilized and viable cells.
abstract: Membrane electropermeabilization relies on the transient permeabilization of the plasma membrane of cells submitted to electric pulses. This method is widely used in cell biology and medicine due to its efficiency to transfer molecules while limiting loss of cell viability. However, very little is known about the consequences of membrane electropermeabilization at the molecular and cellular levels. Progress in the knowledge of the involved mechanisms is a biophysical challenge. As a transient loss of membrane cohesion is associated with membrane permeabilization, our main objective was to detect and visualize at the single-cell level the incidence of phospholipid scrambling and changes in membrane order. We performed studies using fluorescence microscopy with C6-NBD-PC and FM1-43 to monitor phospholipid scrambling and membrane order of mammalian cells. Millisecond permeabilizing pulses induced membrane disorganization by increasing the translocation of phosphatidylcholines according to an ATP-independent process. The pulses induced the formation of long-lived permeant structures that were present during membrane resealing, but were not associated with phosphatidylcholine internalization. These pulses resulted in a rapid phospholipid flip/flop within less than 1s and were exclusively restricted to the regions of the permeabilized membrane. Under such electrical conditions, phosphatidylserine externalization was not detected. Moreover, this electrically-mediated membrane disorganization was not correlated with loss of cell viability. Our results could support the existence of direct interactions between the movement of membrane zwitterionic phospholipids and the electric field.
authors.affiliation: CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, F-31077, Toulouse, France; Université de Toulouse, UPS, IPBS, F-31077, Toulouse, France.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Escoffre
authors.affiliation: CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, F-31077, Toulouse, France; Université de Toulouse, UPS, IPBS, F-31077, Toulouse, France.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Bellard
authors.affiliation: Matwin-Institut Bergonié, 229 cours de l'Argonne, 33076 Bordeaux cedex, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Faurie
authors.affiliation: Eviagenics, Immeuble Villejuif Biopark, 1 Mail du Professeur Georges Mathé, 94800 Villejuif, France.
authors.forename: Sarra C
authors.initials: SC
authors.lastname: Sébaï
authors.affiliation: CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, F-31077, Toulouse, France; Université de Toulouse, UPS, IPBS, F-31077, Toulouse, France.
authors.forename: Muriel
authors.initials: M
authors.lastname: Golzio
authors.affiliation: CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, F-31077, Toulouse, France; Université de Toulouse, UPS, IPBS, F-31077, Toulouse, France. Electronic address: justin.teissie@ipbs.fr.
authors.forename: Justin
authors.initials: J
authors.lastname: Teissié
authors.affiliation: CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, F-31077, Toulouse, France; Université de Toulouse, UPS, IPBS, F-31077, Toulouse, France. Electronic address: rols@ipbs.fr.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Rols
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D002463:Cell Membrane Permeability; D002470:Cell Survival / Q000502:physiology; D003412:Cricetulus; D018274:Electroporation / Q000379:methods; D010713:Phosphatidylcholines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*
chemical_list: D010713:Phosphatidylcholines; D010743:Phospholipids; D000255:Adenosine Triphosphate
keywords: Electropermeabilization; Electroporation; Membrane disorder; Optical imaging; Phospholipid flip-flop