title: Mechanism of an indirect effect of aqueous cigarette smoke extract on the adhesion of monocytic cells to endothelial cells in an in vitro assay revealed by transcriptomics analysis.
abstract: The adhesion of monocytic cells to the "dysfunctional" endothelium constitutes a critical step in the initiation of atherosclerosis. Cigarette smoke (CS) has been shown to contribute to this process, the complex mechanism of which still needs to be unraveled. We developed an in vitro adhesion assay to investigate the CS-induced adhesion of monocytic MM6 cells to human umbilical vein endothelial cells (HUVECs) following exposure to an aqueous CS extract (smoke-bubbled phosphate buffered saline: sbPBS), reasoning that in vivo monocytes and endothelial cells are exposed primarily to soluble constituents from inhaled CS absorbed through the lung alveolar wall. MM6 cell adhesion was increased exclusively by the conditioned medium from sbPBS-exposed MM6 cells, not by direct sbPBS exposure of the HUVECs within a range of sbPBS doses. Using a transcriptomics approach followed by confirmation experiments, we identified different exposure effects on both cell types and a key mechanism by which sbPBS promoted the adhesion of MM6 cells to HUVECs. While sbPBS provoked a strong oxidative stress response in both cell types, the expression of E-selectin, VCAM-1 and ICAM-1, responsible for the adhesion of MM6 cells to HUVECs, was induced in the latter through a proinflammatory paracrine effect. We confirmed that this effect was driven mainly by TNFα produced by MM6 cells exposed to sbPBS. In conclusion, we have elucidated an indirect mechanism by which sbPBS increases the adhesion of monocytic cells to endothelial cells in this in vitro assay that was designed for tobacco product risk assessment while mimicking the in vivo exposure conditions as closely as possible.
authors.affiliation: Philip Morris International R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchâtel, Switzerland. Electronic address: carine.poussin@pmi.com.
authors.forename: Carine
authors.initials: C
authors.lastname: Poussin
authors.affiliation: Philip Morris International R&D, Philip Morris Research Laboratories GmbH, Fuggerstrasse 3, 51149 Cologne, Germany.
authors.forename: Inka
authors.initials: I
authors.lastname: Gallitz
authors.affiliation: Philip Morris International R&D, Philip Morris Research Laboratories GmbH, Fuggerstrasse 3, 51149 Cologne, Germany.
authors.forename: Walter K
authors.initials: WK
authors.lastname: Schlage
authors.affiliation: Philip Morris International R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchâtel, Switzerland.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Steffen
authors.affiliation: Philip Morris International R&D, Philip Morris Research Laboratories GmbH, Fuggerstrasse 3, 51149 Cologne, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Stolle
authors.affiliation: Philip Morris International R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchâtel, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Lebrun
authors.affiliation: Philip Morris International R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchâtel, Switzerland.
authors.forename: Julia
authors.initials: J
authors.lastname: Hoeng
authors.affiliation: Philip Morris International R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchâtel, Switzerland.
authors.forename: Manual C
authors.initials: MC
authors.lastname: Peitsch
authors.affiliation: Philip Morris International R&D, Philip Morris Research Laboratories GmbH, Fuggerstrasse 3, 51149 Cologne, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Lietz
mesh_terms: D002448:Cell Adhesion; D002460:Cell Line; D002478:Cells, Cultured; D045424:Complex Mixtures / Q000633:toxicity*; D019040:E-Selectin / Q000235:genetics; D020869:Gene Expression Profiling; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics; D009000:Monocytes / Q000187:drug effects* / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D012906:Smoke; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics
chemical_list: D045424:Complex Mixtures; D019040:E-Selectin; C546936:SELE protein, human; D012906:Smoke; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1
keywords: Adhesion; Atherosclerosis; Cigarette smoke; Endothelial cells; Microarray; Monocyte