title: Effect of bacterial peptidoglycan on erythrocyte death and adhesion to endothelial cells.
abstract: Peptidoglycans, bacterial wall components, have previously been shown to trigger eryptosis, the suicidal erythrocyte death, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the cell surface. Phosphatidylserine exposing erythrocytes adhere to the vascular wall at least partially by interaction of erythrocytic phosphatidylserine with endothelial CXC chemokine ligand 16 (CXCL16). The present study explored whether peptidoglycan exposure fosters the adhesion of erythrocytes to human umbilical vein endothelial cells (HUVEC). To this end, HUVEC were treated for 48 h with peptidoglycan (10 μg/ml) and CXCL16 abundance determined by confocal microscopy and FACS analysis. Moreover, human erythrocytes were exposed for 48 h to peptidoglycan (10 μg/ml) and phosphatidylserine exposure estimated from binding of fluorescent annexin-V, cell volume from forward scatter in FACS analysis and erythrocyte adhesion to human umbilical vein endothelial cells (HUVEC) from trapping of labeled erythrocytes in a flow chamber. As a result, bacterial peptidoglycan exposure was followed by increased CXCL16 expression in HUVEC as well as erythrocyte shrinkage, phosphatidylserine exposure and adhesion to HUVEC under flow conditions at arterial shear rates. The adhesion was significantly attenuated but not abrogated in the presence of either, erythrocyte phosphatidylserine-coating annexin-V (5 μl/ml) or CXCL16 neutralizing antibody directed against endothelial CXCL16 (4 μg/ml). In conclusion, exposure to peptidoglycan increases endothelial CXCL16 expression and leads to eryptosis followed by phosphatidylserine- and CXCL16-mediated adhesion of eryptotic erythrocytes to vascular endothelial cells.
authors.affiliation: Department of Physiology, University of Tuebingen, Tuebingen, Germany.
authors.forename: Majed
authors.initials: M
authors.lastname: Abed
authors.forename: Syeda T
authors.initials: ST
authors.lastname: Towhid
authors.forename: Tatsiana
authors.initials: T
authors.lastname: Pakladok
authors.forename: Ioana
authors.initials: I
authors.lastname: Alesutan
authors.forename: Friedrich
authors.initials: F
authors.lastname: Götz
authors.forename: Erich
authors.initials: E
authors.lastname: Gulbins
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D017304:Annexin A5 / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects*; D016923:Cell Death / Q000187:drug effects*; D002478:Cells, Cultured; D000075743:Chemokine CXCL16; D019743:Chemokines, CXC / Q000032:analysis; D042783:Endothelial Cells / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology*; D004912:Erythrocytes / Q000187:drug effects* / Q000502:physiology*; D005434:Flow Cytometry; D006801:Humans; D018613:Microscopy, Confocal; D010457:Peptidoglycan / Q000378:metabolism*; D010718:Phosphatidylserines / Q000032:analysis; D011485:Protein Binding; D051116:Receptors, Scavenger / Q000032:analysis
chemical_list: D017304:Annexin A5; C423727:CXCL16 protein, human; D000075743:Chemokine CXCL16; D019743:Chemokines, CXC; D010457:Peptidoglycan; D010718:Phosphatidylserines; D051116:Receptors, Scavenger