A Banning

A Dieudonne

A El-Sayed

A Ludwig

A Schneider

AF McGettrick

AM Lundberg

Benjamin J. Nichols

C Neumann-Giesen

C Ospelt

CA Baumann

CG Hansen

Christian Fork

D Volonte

DE Saslowsky

E Kuang

EV Vassilieva

GP Otto

GP Solis

GV Limmon

I Carcea

I Fernow

J Ramadoss

JJ Williams

Juliane Hitzel

K Ezzat

KB Kim

KK Sorensen

L Ge

LS Le

M Amaddii

M Frick

M Kirkham

M Meister

M Yamashita

MS Lee

MW Lawless

OO Glebov

P Balogh

R Lafyatis

Ralf P. Brandes

Ritva Tikkanen

S Pust

T Babuke

TH Lee

V Bitsikas

Abstract
          Endothelial cells are important elements in the vascular response to danger-associated molecules signaling through toll-like receptors (TLRs). Flotillin-1 and -2 are markers of membrane rafts but their true endothelial function is unknown. We hypothesized that flotillins are required for TLR signaling in human umbilical vein endothelial cells (HUVECs). Knockdown of flotillin-1 by shRNA decreased the TLR3-mediated poly-I:C-induced but not the TLR4-mediated LPS-induced inflammatory activation of HUVEC. As TLR3 but not TLR4 signals through the endosomal compartment, flotillin-1 might be involved in the transport of poly-I:C to its receptor. Consistently, uptake of poly-I:C was attenuated by flotillin-1 knockdown and probably involved the scavenger receptor SCARA4 as revealed by knockdown of this receptor. To determine the underlying mechanism, SILAC proteomics was performed. Down-regulation of flotillin-1 led to a reduction of the structural caveolae proteins caveolin-1, cavin-1 and -2, suggesting a role of flotillin-1 in caveolae formation. Flotillin-1 and caveolin-1 colocalized within the cell, and knockdown of flotillin-1 decreased caveolin-1 expression in an endoplasmic reticulum stress-dependent manner. Importantly, downregulation of caveolin-1 also attenuated TLR3-induced signaling. To demonstrate the importance of this finding, cell adhesion was studied. Flotillin-1 shRNA attenuated the poly-I:C-mediated induction of the adhesion molecules VCAM-1 and ICAM-1. As a consequence, the poly-I:C-induced adhesion of peripheral blood mononuclear cells onto HUVECs was significantly attenuated by flotillin-1 shRNA. Collectively, these data suggest that interaction between flotillin-1 and caveolin-1 may facilitate the transport of TLR3-ligands to its intracellular receptor and enables inflammatory TLR3 signaling.</jats:p

Crossref

Basic Research in Cardiology

Flotillin-1 facilitates toll-like receptor 3 signaling in human endothelial cells

https://link.springer.com/content/pdf/10.1007%2Fs00395-014-0439-4.pdf

Flotillin-1 facilitates toll-like receptor 3 signaling in human endothelial cells

Abstract

Similar works

Full text

Available Versions

Crossref