title: Regulation of the micromechanical properties of pulmonary endothelium by S1P and thrombin: role of cortactin.
abstract: Disruption of pulmonary endothelial cell (EC) barrier function is a critical pathophysiologic event in highly morbid inflammatory conditions such as sepsis and acute respiratory disease stress syndrome. Actin cytoskeleton, an essential regulator of endothelial permeability, is a dynamic structure whose stimuli-induced rearrangement is linked to barrier modulation. Here, we used atomic force microscopy to characterize structural and mechanical changes in the F-actin cytoskeleton of cultured human pulmonary artery EC in response to both barrier-enhancing (induced by sphingosine 1-phosphate (S1P)) and barrier-disrupting (induced by thrombin) conditions. Atomic force microscopy elasticity measurements show differential effects: for the barrier protecting molecule S1P, the elastic modulus was elevated significantly on the periphery; for the barrier-disrupting molecule thrombin, on the other hand, it was elevated significantly in the central region of the cell. The force and elasticity maps correlate with F-actin rearrangements as identified by immunofluorescence analysis. Significantly, reduced expression (via siRNA) of cortactin, an actin-binding protein essential to EC barrier regulation, resulted in a shift in the S1P-mediated elasticity pattern to more closely resemble control, unstimulated endothelium.
authors.affiliation: Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA. ftarce@uchicago.edu
authors.forename: Fernando Terán
authors.initials: FT
authors.lastname: Arce
authors.forename: Jenny L
authors.initials: JL
authors.lastname: Whitlock
authors.forename: Anna A
authors.initials: AA
authors.lastname: Birukova
authors.forename: Konstantin G
authors.initials: KG
authors.lastname: Birukov
authors.forename: Morton F
authors.initials: MF
authors.lastname: Arnsdorf
authors.forename: Ratnesh
authors.initials: R
authors.lastname: Lal
authors.forename: Joe G N
authors.initials: JG
authors.lastname: Garcia
authors.forename: Steven M
authors.initials: SM
authors.lastname: Dudek
mesh_terms: D000199:Actins / Q000737:chemistry / Q000502:physiology*; D051356:Cortactin / Q000737:chemistry / Q000502:physiology*; D004548:Elasticity; D004730:Endothelium, Vascular / Q000737:chemistry / Q000502:physiology*; D006801:Humans; D008246:Lysophospholipids / Q000737:chemistry / Q000502:physiology*; D018625:Microscopy, Atomic Force / Q000379:methods; D011651:Pulmonary Artery / Q000737:chemistry / Q000502:physiology*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000502:physiology; D013314:Stress, Mechanical; D013917:Thrombin / Q000737:chemistry / Q000502:physiology*
chemical_list: D000199:Actins; D051356:Cortactin; D008246:Lysophospholipids; C060506:sphingosine 1-phosphate; D013917:Thrombin; D013110:Sphingosine