Regulation of the micromechanical properties of pulmonary endothelium by S1P and thrombin: role of cortactin.
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.
Arce
Fernando Terán
FT
Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA. ftarce@uchicago.edu
Whitlock
Jenny L
JL
Birukova
Anna A
AA
Birukov
Konstantin G
KG
Arnsdorf
Morton F
MF
Lal
Ratnesh
R
Garcia
Joe G N
JG
Dudek
Steven M
SM
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*
D000199:Actins; D051356:Cortactin; D008246:Lysophospholipids; C060506:sphingosine 1-phosphate; D013917:Thrombin; D013110:Sphingosine