title: C7 is expressed on endothelial cells as a trap for the assembling terminal complement complex and may exert anti-inflammatory function.
abstract: We describe a novel localization of C7 as a membrane-bound molecule on endothelial cells (ECs). Data obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Western blot analysis, Northern blot analysis, and mass spectrometry revealed that membrane-associated C7 (mC7) was indistinguishable from soluble C7 and was associated with vimentin on the cell surface. mC7 interacted with the other late complement components to form membrane-bound TCC (mTCC). Unlike the soluble SC5b-9, mTCC failed to stimulate ECs to express adhesion molecules, to secrete IL-8, and to induce albumin leakage through a monolayer of ECs, and more importantly protected ECs from the proinflammatory effect of SC5b-9. Our data disclose the possibility of a novel role of mC7 that acts as a trap for the late complement components to control excessive inflammation induced by SC5b-9.
authors.affiliation: Department of Life Sciences, University of Trieste, Trieste, Italy.
authors.forename: Fleur
authors.initials: F
authors.lastname: Bossi
authors.forename: Lucia
authors.initials: L
authors.lastname: Rizzi
authors.forename: Roberta
authors.initials: R
authors.lastname: Bulla
authors.forename: Alessandra
authors.initials: A
authors.lastname: Debeus
authors.forename: Claudio
authors.initials: C
authors.lastname: Tripodo
authors.forename: Paola
authors.initials: P
authors.lastname: Picotti
authors.forename: Elena
authors.initials: E
authors.lastname: Betto
authors.forename: Paolo
authors.initials: P
authors.lastname: Macor
authors.forename: Carlo
authors.initials: C
authors.lastname: Pucillo
authors.forename: Reinhard
authors.initials: R
authors.lastname: Würzner
authors.forename: Francesco
authors.initials: F
authors.lastname: Tedesco
mesh_terms: D002478:Cells, Cultured; D003184:Complement C7 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D015938:Complement Membrane Attack Complex / Q000276:immunology / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D016209:Interleukin-8 / Q000276:immunology / Q000378:metabolism; D008565:Membrane Proteins / Q000276:immunology / Q000378:metabolism; D040901:Proteomics; D012333:RNA, Messenger / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology; D014657:Vasculitis / Q000276:immunology* / Q000378:metabolism*; D014746:Vimentin / Q000378:metabolism
chemical_list: D003184:Complement C7; D015938:Complement Membrane Attack Complex; D016209:Interleukin-8; D008565:Membrane Proteins; D012333:RNA, Messenger; D014746:Vimentin