%0 Journal Article %T Plasma membrane microdomains regulate TACE-dependent TNFR1 shedding in human endothelial cells. %+ Department of Anatomy, Histology, Forensic Medicine and Orthopedic [Roma] (DAHFMO) %+ Department of Immunobiology %A d'Alessio, Alessio %A Esposito, Bianca %A Giampietri, Claudia %A Ziparo, Elio %A Pober, Jordan S %A Filippini, Antonio %Z This work was supported by the "Rientro dei Cervelli" Grant Program from Ministero dell'Universit‡ e della Ricerca (MIUR) to AD, from Italian Ministry Health Grant 2007 to EZ, from PRIN 2008 to AF, and a grant from the U.S. National Institutes of Health (HL036003) to JSP %< avec comité de lecture %@ 1582-1838 %J Journal of Cellular and Molecular Medicine %I Wiley Open Access %V 16 %N 3 %P 627-36 %8 2012-03 %D 2012 %R 10.1111/j.1582-4934.2011.01353.x %M 21645239 %Z Life Sciences [q-bio]/Cellular BiologyJournal articles %X 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. %G English %2 https://riip.hal.science/pasteur-00966442/document %2 https://riip.hal.science/pasteur-00966442/file/D_Alessioetal2012.pdf %L pasteur-00966442 %U https://riip.hal.science/pasteur-00966442 %~ RIIP