title: Peripheral blood mononuclear cells induce programmed cell death in human endothelial cells and may prevent repair: role of cytokines.
abstract: Human umbilical vein endothelial cells (HUVECs) undergo programmed cell death (apoptosis) after coculture with peripheral blood mononuclear cells (PBMCs) preactivated by ionizing radiation (IR) or by bacterial endotoxin (lipopolysaccharide [LPS]). Cell-to-cell contact-mediated apoptosis could be blocked in both cases by anti-tumor necrosis factor-alpha (anti-TNF-alpha) monoclonal antibody MAK195 and also by the antagonistic cytokine interleukin-10 (IL-10). Cell-free PBMC supernatants from both preactivation treatments were sufficient to trigger endothelial apoptosis. In contrast, MAK195 and IL-10 were found to be ineffective in this system, suggesting a TNF-alpha-independent mechanism. However, N-Acetylcystein, an antioxidant, fully abrogated programmed cell death mediated by the supernatant of IR-treated PBMCs, but not of LPS-treated PBMCs. Additionally, we found that coculture and cell-free supernatants of preactivated as well as untreated PBMCs caused cell cycle arrest in proliferating EC in G(0/1), which could be relieved by IL-10, but not by anti-TNF-alpha. Further analysis showed that transforming growth factor-beta, which was constitutively expressed in the supernatant of PBMCs, namely lymphocytes, was responsible for this. These data suggest a pathophysiologic model in which preactivated PBMCs cause EC damage and may prevent blood vessel repair by arresting the proliferation of ECs. This could contribute to the understanding of various clinical endothelial complications that occur after irradiation as well as in cases of endotoxemia or related inflammatory states.
authors.affiliation: Forschungszentrum für Umwelt und Gesundheit-Institutes for Clinical Molecular Biology, Hospital Grosshadern, Munich, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Lindner
authors.forename: E
authors.initials: E
authors.lastname: Holler
authors.forename: B
authors.initials: B
authors.lastname: Ertl
authors.forename: G
authors.initials: G
authors.lastname: Multhoff
authors.forename: M
authors.initials: M
authors.lastname: Schreglmann
authors.forename: I
authors.initials: I
authors.lastname: Klauke
authors.forename: S
authors.initials: S
authors.lastname: Schultz-Hector
authors.forename: G
authors.initials: G
authors.lastname: Eissner
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D002474:Cell-Free System / Q000502:physiology; D002478:Cells, Cultured; D018920:Coculture Techniques; D016207:Cytokines / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D016193:G1 Phase / Q000502:physiology; D006801:Humans; D016753:Interleukin-10 / Q000502:physiology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000528:radiation effects; D008565:Membrane Proteins / Q000502:physiology; D016192:Resting Phase, Cell Cycle / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000096:biosynthesis / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000502:physiology; D014471:Umbilical Veins
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10