title: During apoptosis HMGB1 is translocated into apoptotic cell-derived membranous vesicles.
abstract: High mobility group box protein B1 (HMGB1), a nuclear protein reportedly involved in the structural organisation of DNA, is released from necrotic cells or upon cellular activation. After its release into the extracellular space, HMGB1 serves as a mediator of inflammation. In contrast to necrotic cells, apoptotic ones usually do not release HMGB1. Formation and release of membranous vesicles is a well-known feature of apoptotic cell death. Only recently, subcellular membrane vesicles, such as those released during apoptotic cell death have been identified as immune regulators and as mediators of cell to cell communication. We and others have previously detected nuclear antigens within apoptosis-released membranous vesicles and HMGB1 together with nuclear antigens has been discussed to be a key player in etiology and pathogenesis of autoimmune diseases. On this background, we analysed whether HMGB1 is included in the membranous vesicles generated by apoptosing cells. Employing immune blots we observed abundand amounts of HMGB1 in the fraction of the small membraneous particles isolated from cell culture supernatants and conclude that HMGB1 is translocated into vesicles generated during apoptosis.
authors.affiliation: Department of Internal Medicine V, Division of Rheumatology, University Hospital Heidelberg, Heidelberg, Germany. martin.schiller@med.uni-heidelberg.de
authors.forename: Martin
authors.initials: M
authors.lastname: Schiller
authors.forename: Petra
authors.initials: P
authors.lastname: Heyder
authors.forename: Saskia
authors.initials: S
authors.lastname: Ziegler
authors.forename: Anna
authors.initials: A
authors.lastname: Niessen
authors.forename: Laura
authors.initials: L
authors.lastname: Claßen
authors.forename: Anna
authors.initials: A
authors.lastname: Lauffer
authors.forename: Hanns-Martin
authors.initials: HM
authors.lastname: Lorenz
mesh_terms: D017209:Apoptosis / Q000276:immunology*; D002478:Cells, Cultured; D024243:HMGB1 Protein / Q000378:metabolism*; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology; D021381:Protein Transport / Q000276:immunology*; D050683:R-SNARE Proteins / Q000378:metabolism*
chemical_list: D024243:HMGB1 Protein; D018836:Inflammation Mediators; D050683:R-SNARE Proteins