title: TiO2 nanoparticles induce endothelial cell activation in a pneumocyte-endothelial co-culture model.
abstract: The effects of particulate matter (PM) on endothelial cells have been evaluated in vitro by exposing isolated endothelial cells to different types of PM. Although some of the findings from these experiments have been corroborated by in vivo studies, an in vitro model that assesses the interaction among different cell types is necessary to achieve more realistic assays. We developed an in vitro model that mimics the alveolar-capillary interface, and we challenged the model using TiO nanoparticles (TiO-NPs). Human umbilical endothelial cells (HUVECs) were cultured on the basolateral side of a membrane and pneumocytes (A549) on the apical side. Confluent co-cultures were exposed on the apical side to 10 μg/cm of TiO-NPs or 10 ng/mL of TNFα for 24 h. Unexposed cultures were used as negative controls. We evaluated monocyte adhesion to HUVECs, adhesion molecule expression, nitric oxide concentration and proinflammatory cytokine release. The TiO-NPs added to the pneumocytes induced a 3- to 4-fold increase in monocyte adhesion to the HUVECs and significant increases in the expression of adhesion molecules (4-fold for P-selectin at 8 h, and about 8- and 10-fold for E-selectin, ICAM-1, VCAM-1 and PECAM-1 at 24 h). Nitric oxide production also increased significantly (2-fold). These results indicate that exposing pneumocytes to TiO-NPs causes endothelial cell activation.
authors.affiliation: Environmental Toxicology Laboratory, Subdirección de Investigación Básica, Instituto Nacional de Cancerología, Mexico.
authors.forename: María Del Pilar
authors.initials: Mdel P
authors.lastname: Ramos-Godínez
authors.forename: Blanca Eunice
authors.initials: BE
authors.lastname: González-Gómez
authors.forename: Angélica
authors.initials: A
authors.lastname: Montiel-Dávalos
authors.forename: Rebeca
authors.initials: R
authors.lastname: López-Marure
authors.forename: Ernesto
authors.initials: E
authors.lastname: Alfaro-Moreno
mesh_terms: D056809:Alveolar Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000378:metabolism; D045744:Cell Line, Tumor; D018920:Coculture Techniques; D016207:Cytokines / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D053768:Metal Nanoparticles; D009569:Nitric Oxide / Q000378:metabolism; D014025:Titanium / Q000494:pharmacology*; D020298:U937 Cells
chemical_list: D015815:Cell Adhesion Molecules; D016207:Cytokines; C009495:titanium dioxide; D009569:Nitric Oxide; D014025:Titanium