title: Membrane potential depolarization decreases the stiffness of vascular endothelial cells.
abstract: The stiffness of vascular endothelial cells is crucial to mechanically withstand blood flow and, at the same time, to control deformation-dependent nitric oxide release. However, the regulation of mechanical stiffness is not yet understood. There is evidence that a possible regulator is the electrical plasma membrane potential difference. Using a novel technique that combines fluorescence-based membrane potential recordings with atomic force microscopy (AFM)-based stiffness measurements, the present study shows that membrane depolarization is associated with a decrease in the stiffness of endothelial cells. Three different depolarization protocols were applied, all of which led to a similar and significant decrease in cell stiffness, independently of changes in cell volume. Moreover, experiments using the actin-destabilizing agent cytochalasin D indicated that depolarization acts by affecting the cortical actin cytoskeleton. A model is proposed whereby a change of the electrical field across the plasma membrane is directly sensed by the submembranous actin network, regulating the actin polymerization:depolymerization ratio and thus cell stiffness. This depolarization-induced decrease in the stiffness of endothelial cells could play a role in flow-mediated nitric-oxide-dependent vasodilation.
authors.affiliation: Institute of Physiology II, University of Münster, Robert-Koch-Str. 27b, 48149 Münster, Germany. ccallies@web.de
authors.forename: Chiara
authors.initials: C
authors.lastname: Callies
authors.forename: Johannes
authors.initials: J
authors.lastname: Fels
authors.forename: Ivan
authors.initials: I
authors.lastname: Liashkovich
authors.forename: Katrin
authors.initials: K
authors.lastname: Kliche
authors.forename: Pia
authors.initials: P
authors.lastname: Jeggle
authors.forename: Kristina
authors.initials: K
authors.lastname: Kusche-Vihrog
authors.forename: Hans
authors.initials: H
authors.lastname: Oberleithner
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D017609:Barium Compounds / Q000494:pharmacology; D002417:Cattle; D002460:Cell Line; D048429:Cell Size; D002712:Chlorides / Q000737:chemistry / Q000494:pharmacology; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D018625:Microscopy, Atomic Force; D011188:Potassium / Q000494:pharmacology; D055550:Protein Stability; D013314:Stress, Mechanical
chemical_list: D000199:Actins; D017609:Barium Compounds; D002712:Chlorides; C024986:barium chloride; D011188:Potassium