title: LPS activates ADAM9 dependent shedding of ACE from endothelial cells.
abstract: Angiotensin-I converting enzyme (ACE) is a zinc dependent peptidase with a major role in regulating vasoactive peptide metabolism. ACE, a transmembrane protein, undergoes proteolysis, or shedding, by an as yet unidentified proteinase to release a catalytically active soluble form of the enzyme. Physiologically, soluble ACE in plasma is derived primarily from endothelial cells. We demonstrate that ACE shedding from confluent endothelial cells is increased in response to bacterial lipopolysaccharide, but not phorbol esters. Characterisation of lipopolysaccharide stimulated shedding showed that there is a lag phase before soluble ACE can be detected which is sensitive to inhibitors of translation, NF-κB, TNFα and TNFR-I/II. The shedding phase is less sensitive to these inhibitors, but is ablated by BB-94, a Matrix Metalloproteinase (MMP)/A Disintegrin and Metalloproteinase (ADAM) inhibitor. Tissue Inhibitor of Metalloproteinase (TIMP) profiling suggested a requirement for ADAM9 in lipopolysaccharide induced ACE shedding, which was confirmed by depletion with siRNA. Transient transfection of ADAM9 and ACE cDNAs into HEK293 cells demonstrated that ADAM9 requires both membrane anchorage and its catalytic domain to shed ACE.
authors.affiliation: Department of Oncology, University of Cambridge, Cancer Research UK Cambridge Research Institute, The Li Ka Shing Centre, Robinson Way CB2 0RE, UK. w.english@sheffield.ac.uk
authors.forename: William R
authors.initials: WR
authors.lastname: English
authors.forename: Pierre
authors.initials: P
authors.lastname: Corvol
authors.forename: Gillian
authors.initials: G
authors.lastname: Murphy
mesh_terms: D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D002462:Cell Membrane / Q000201:enzymology; D018076:DNA, Complementary; D019483:Disintegrins / Q000037:antagonists & inhibitors; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D057809:HEK293 Cells; D006801:Humans; D008070:Lipopolysaccharides / Q000378:metabolism* / Q000494:pharmacology; D061965:Matrix Metalloproteinase Inhibitors; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D045726:Metalloproteases / Q000037:antagonists & inhibitors; D016328:NF-kappa B / Q000378:metabolism; D007703:Peptidyl-Dipeptidase A; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000494:pharmacology; D010703:Phorbol Esters / Q000378:metabolism / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000378:metabolism; D013876:Thiophenes / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D019483:Disintegrins; D008070:Lipopolysaccharides; D061965:Matrix Metalloproteinase Inhibitors; D008565:Membrane Proteins; D016328:NF-kappa B; D010703:Phorbol Esters; D011480:Protease Inhibitors; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D013876:Thiophenes; D014409:Tumor Necrosis Factor-alpha; D010649:Phenylalanine; C080985:batimastat; D045726:Metalloproteases; D007703:Peptidyl-Dipeptidase A; D051722:ADAM Proteins; C098339:ADAM9 protein, human