title: Transcriptomic analysis reveals novel mechanistic insight into murine biological responses to multi-walled carbon nanotubes in lungs and cultured lung epithelial cells.
abstract: There is great interest in substituting animal work with in vitro experimentation in human health risk assessment; however, there are only few comparisons of in vitro and in vivo biological responses to engineered nanomaterials. We used high-content genomics tools to compare in vivo pulmonary responses of multiwalled carbon nanotubes (MWCNT) to those in vitro in cultured lung epithelial cells (FE1) at the global transcriptomic level. Primary size, surface area and other properties of MWCNT- XNRI -7 (Mitsui7) were characterized using DLS, SEM and TEM. Mice were exposed via a single intratracheal instillation to 18, 54, or 162 μg of Mitsui7/mouse. FE1 cells were incubated with 12.5, 25 and 100 μg/ml of Mitsui7. Tissue and cell samples were collected at 24 hours post-exposure. DNA microarrays were employed to establish mechanistic differences and similarities between the two models. Microarray results were confirmed using gene-specific RT-qPCR. Bronchoalveolar lavage (BAL) fluid was assessed for indications of inflammation in vivo. A strong dose-dependent activation of acute phase and inflammation response was observed in mouse lungs reflective mainly of an inflammatory response as observed in BAL. In vitro, a wide variety of core cellular functions were affected including transcription, cell cycle, and cellular growth and proliferation. Oxidative stress, fibrosis and inflammation processes were altered in both models. Although there were similarities observed between the two models at the pathway-level, the specific genes altered under these pathways were different, suggesting that the underlying mechanisms of responses are different in cells in culture and the lung tissue. Our results suggest that careful consideration should be given in selecting relevant endpoints when substituting animal with in vitro testing.
authors.affiliation: National Research Centre for the Working Environment, Copenhagen, Denmark ; Department of Science, Systems and Models, Roskilde University, Roskilde, Denmark.
authors.forename: Sarah
authors.initials: S
authors.lastname: Søs Poulsen
authors.forename: Nicklas R
authors.initials: NR
authors.lastname: Jacobsen
authors.forename: Sarah
authors.initials: S
authors.lastname: Labib
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wu
authors.forename: Mainul
authors.initials: M
authors.lastname: Husain
authors.forename: Andrew
authors.initials: A
authors.lastname: Williams
authors.forename: Jesper P
authors.initials: JP
authors.lastname: Bøgelund
authors.forename: Ole
authors.initials: O
authors.lastname: Andersen
authors.forename: Carsten
authors.initials: C
authors.lastname: Købler
authors.forename: Kristian
authors.initials: K
authors.lastname: Mølhave
authors.forename: Zdenka O
authors.initials: ZO
authors.lastname: Kyjovska
authors.forename: Anne T
authors.initials: AT
authors.lastname: Saber
authors.forename: Håkan
authors.initials: H
authors.lastname: Wallin
authors.forename: Carole L
authors.initials: CL
authors.lastname: Yauk
authors.forename: Ulla
authors.initials: U
authors.lastname: Vogel
authors.forename: Sabina
authors.initials: S
authors.lastname: Halappanavar
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002478:Cells, Cultured; D016000:Cluster Analysis; D004781:Environmental Exposure; D004847:Epithelial Cells / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling; D053263:Gene Regulatory Networks; D007249:Inflammation / Q000209:etiology; D008168:Lung / Q000378:metabolism*; D051379:Mice; D058977:Molecular Sequence Annotation; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity* / Q000648:ultrastructure; D010316:Particle Size; D015203:Reproducibility of Results; D020545:Respiratory Mucosa / Q000378:metabolism*; D015398:Signal Transduction; D059467:Transcriptome
chemical_list: D037742:Nanotubes, Carbon