title: Disassembly of actin structures by nanosecond pulsed electric field is a downstream effect of cell swelling.
abstract: Disruption of the actin cytoskeleton structures was reported as one of the characteristic effects of nanosecond-duration pulsed electric field (nsPEF) in both mammalian and plant cells. We utilized CHO cells that expressed the monomeric fluorescent protein (mApple) tagged to actin to test if nsPEF modifies the cell actin directly or as a consequence of cell membrane permeabilization. A train of four 600-ns pulses at 19.2 kV/cm (2 Hz) caused immediate cell membrane poration manifested by YO-PRO-1 dye uptake, gradual cell rounding and swelling. Concurrently, bright actin features were replaced by dimmer and uniform fluorescence of diffuse actin. To block the nsPEF-induced swelling, the bath buffer was isoosmotically supplemented with an electropore-impermeable solute (sucrose). A similar addition of a smaller, electropore-permeable solute (adonitol) served as a control. We demonstrated that sucrose efficiently blocked disassembly of actin features by nsPEF, whereas adonitol did not. Sucrose also attenuated bleaching of mApple-tagged actin in nsPEF-treated cells (as integrated over the cell volume), although did not fully prevent it. We conclude that disintegration of the actin cytoskeleton was a result of cell swelling, which, in turn, was caused by cell permeabilization by nsPEF and transmembrane diffusion of solutes which led to the osmotic imbalance.
authors: Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA. Electronic address: 2andrei@pakhomov.net.
authors: Andrei G
authors: AG
authors: Pakhomov
authors: Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA; Dept. of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA.
authors: Shu
authors: S
authors: Xiao
authors: Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA.
authors: Olga N
authors: ON
authors: Pakhomova
authors: Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA.
authors: Iurii
authors: I
authors: Semenov
authors: Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Fort Sam Houston, TX, USA.
authors: Marjorie A
authors: MA
authors: Kuipers
authors: Radio Frequency Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711th Human Performance Wing, Air Force Research Laboratory, Fort Sam Houston, TX, USA.
authors: Bennett L
authors: BL
authors: Ibey
mesh_terms: D000199:Actins / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D048430:Cell Shape; D048429:Cell Size; D006224:Cricetinae; D003412:Cricetulus; D003599:Cytoskeleton / Q000378:metabolism; D004560:Electricity; D018274:Electroporation; D009995:Osmosis
chemical_list: D000199:Actins
keywords: Cytoskeleton; Electric pulses; Electroporation; Nanopores; Plasma membrane