title: Loss of gap junctional intercellular communication in rat lung epithelial cells exposed to quartz particles.
abstract: Chronic inhalation of quartz particles has been implicated in lung diseases including silicosis and cancer. The aim of this study was to investigate whether quartz particles affect gap junctional intercellular communication (GJIC) in rat lung epithelial cells (RLE-6TN). Here, we demonstrate that exposure of RLE-6TN cells to subtoxic doses of DQ12 standard quartz resulted in an up to 55% reduction of GJIC, as determined in a dye transfer assay. We show that connexin-43 (Cx43) is the major connexin responsible for intercellular communication in these lung epithelial cells and that exposure to quartz particles induces a significant internalization of Cx43. Downregulation of GJIC was attenuated by N-acetyl cysteine, suggesting the involvement of reactive oxygen species and/or cellular thiol homeostasis in the regulation of GJIC. Furthermore, an inhibitor of activation of extracellular signal-regulated kinases prevented the loss of GJIC in cells exposed to DQ12 quartz, although no direct phosphorylation of Cx43 upon exposure to DQ12 was detected.
authors.affiliation: Institut für Umweltmedizinische Forschung at Heinrich-Heine Universität Düsseldorf gGmbH, Düsseldorf, Germany.
authors.forename: Niloofar
authors.initials: N
authors.lastname: Ale-Agha
authors.forename: Catrin
authors.initials: C
authors.lastname: Albrecht
authors.forename: Lars-Oliver
authors.initials: LO
authors.lastname: Klotz
mesh_terms: D000818:Animals; D002450:Cell Communication / Q000187:drug effects*; D002478:Cells, Cultured; D018031:Connexin 43 / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D017629:Gap Junctions / Q000187:drug effects*; D008168:Lung / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation; D011791:Quartz / Q000633:toxicity*; D051381:Rats; D012822:Silicon Dioxide / Q000633:toxicity
chemical_list: D018031:Connexin 43; D011791:Quartz; D012822:Silicon Dioxide