title: The Relationship between fenestrations, sieve plates and rafts in liver sinusoidal endothelial cells.
abstract: Fenestrations are transcellular pores in endothelial cells that facilitate transfer of substrates between blood and the extravascular compartment. In order to understand the regulation and formation of fenestrations, the relationship between membrane rafts and fenestrations was investigated in liver sinusoidal endothelial cells where fenestrations are grouped into sieve plates. Three dimensional structured illumination microscopy, scanning electron microscopy, internal reflectance fluorescence microscopy and two-photon fluorescence microscopy were used to study liver sinusoidal endothelial cells isolated from mice. There was an inverse distribution between sieve plates and membrane rafts visualized by structured illumination microscopy and the fluorescent raft stain, Bodipy FL C5 ganglioside GM1. 7-ketocholesterol and/or cytochalasin D increased both fenestrations and lipid-disordered membrane, while Triton X-100 decreased both fenestrations and lipid-disordered membrane. The effects of cytochalasin D on fenestrations were abrogated by co-administration of Triton X-100, suggesting that actin disruption increases fenestrations by its effects on membrane rafts. Vascular endothelial growth factor (VEGF) depleted lipid-ordered membrane and increased fenestrations. The results are consistent with a sieve-raft interaction, where fenestrations form in non-raft lipid-disordered regions of endothelial cells once the membrane-stabilizing effects of actin cytoskeleton and membrane rafts are diminished.
authors.affiliation: Centre for Education and Research on Ageing, University of Sydney, Australia.
authors.forename: Dmitri
authors.initials: D
authors.lastname: Svistounov
authors.forename: Alessandra
authors.initials: A
authors.lastname: Warren
authors.forename: Gregory P
authors.initials: GP
authors.lastname: McNerney
authors.forename: Dylan M
authors.initials: DM
authors.lastname: Owen
authors.forename: Dusan
authors.initials: D
authors.lastname: Zencak
authors.forename: Svetlana N
authors.initials: SN
authors.lastname: Zykova
authors.forename: Harry
authors.initials: H
authors.lastname: Crane
authors.forename: Thomas
authors.initials: T
authors.lastname: Huser
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Quinn
authors.forename: Bård
authors.initials: B
authors.lastname: Smedsrød
authors.forename: David G
authors.initials: DG
authors.lastname: Le Couteur
authors.forename: Victoria C
authors.initials: VC
authors.lastname: Cogger
mesh_terms: D000199:Actins / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D021961:Cell Membrane Structures / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D007653:Ketocholesterols / Q000494:pharmacology; D008099:Liver / Q000166:cytology* / Q000187:drug effects / Q000196:embryology; D021962:Membrane Microdomains / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D051379:Mice; D008810:Mice, Inbred C57BL; D008846:Micromanipulation; D017830:Octoxynol / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D000199:Actins; D007653:Ketocholesterols; D042461:Vascular Endothelial Growth Factor A; D017830:Octoxynol; C003001:7-ketocholesterol