Plasma membrane microdomains regulate TACE‐dependent TNFR1 shedding in human endothelial cells

Journal of Cellular and Molecular Medicine

Alessio D.&rsquoAlessio²  Bianca Esposito²  Claudia Giampietri²  Elio Ziparo²  Jordan S. Pober¹ 

[1] Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA;Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Anatomy, Histology, Forensic Medicine and Orthopedics–Section of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy

关键词: TACE;    caveolin‐1;    lipid rafts;    TNF‐receptor;    histamine;    inflammation;    endothelium;   

DOI  :  10.1111/j.1582-4934.2011.01353.x

来源: Wiley

【 摘 要 】

Abstract

Upon stimulation by histamine, human vascular endothelial cells (EC) shed a soluble form of tumour necrosis factor receptor 1 (sTNFR1) that binds up free TNF, dampening the inflammatory response. Shedding occurs through proteolytic cleavage of plasma membrane-expressed TNFR1 catalysed by TNF-α converting enzyme (TACE). Surface expressed TNFR1 on EC is largely sequestered into specific plasma membrane microdomains, the lipid rafts/caveolae. The purpose of this study was to determine the role of these domains in TACE-mediated TNFR1 shedding in response to histamine. Human umbilical vein endothelial cells derived EA.hy926 cells respond to histamine via H1 receptors to shed TNFR1. Both depletion of cholesterol by methyl-β-cyclodextrin and small interfering RNA knockdown of the scaffolding protein caveolin-1 (cav-1), treatments that disrupt caveolae, reduce histamine-induced shedding of membrane-bound TNFR1. Moreover, immunoblotting of discontinuous sucrose gradient fractions show that TACE, such as TNFR1, is present within low-density membrane fractions, concentrated within caveolae, in unstimulated EA.hy926 endothelial cells and co-immunoprecipitates with cav-1. Silencing of cav-1 reduces the levels of both TACE and TNFR1 protein and displaces TACE, from low-density membrane fractions where TNFR1 remains. In summary, we show that endothelial lipid rafts/caveolae co-localize TACE to surface expressed TNFR1, promoting efficient shedding of sTNFR1 in response to histamine.

【 授权许可】

Unknown   
© 2011 The Authors Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd