title: Extensive temporal transcriptome and microRNA analyses identify molecular mechanisms underlying mitochondrial dysfunction induced by multi-walled carbon nanotubes in human lung cells.
abstract: Understanding toxicity pathways of engineered nanomaterials (ENM) has recently been brought forward as a key step in twenty-first century ENM risk assessment. Molecular mechanisms linked to phenotypic end points is a step towards the development of toxicity tests based on key events, which may allow for grouping of ENM according to their modes of action. This study identified molecular mechanisms underlying mitochondrial dysfunction in human bronchial epithelial BEAS 2B cells following exposure to one of the most studied multi-walled carbon nanotubes (Mitsui MWCNT-7). Asbestos was used as a positive control and a non-carcinogenic glass wool material was included as a negative fibre control. Decreased mitochondrial membrane potential (MMP↓) was observed for MWCNTs at a biologically relevant dose (0.25 μg/cm(2)) and for asbestos at 2 μg/cm(2), but not for glass wool. Extensive temporal transcriptomic and microRNA expression analyses identified a 330-gene signature (including 26 genes with known mitochondrial function) related to MWCNT- and asbestos-induced MMP↓. Forty-nine of the MMP↓-associated genes showed highly similar expression patterns over time (six time points) and the majority was found to be regulated by two transcription factors strongly involved in mitochondrial homeostasis, APP and NRF1. In addition, four miRNAs were correlated with MMP↓ and one of them, miR-1275, was found to negatively correlate with a large part of the MMP↓-associated genes. Cellular processes such as gluconeogenesis, mitochondrial LC-fatty acid β-oxidation and spindle microtubule function were enriched among the MMP↓-associated genes and miRNAs. These results are expected to be useful in the identification of key events in ENM-related toxicity pathways for the development of molecular screening techniques.
authors.affiliation: Department of Toxicogenomics, Maastricht University , Maastricht , The Netherlands .
authors.forename: Penny
authors.initials: P
authors.lastname: Nymark
authors.forename: Peter
authors.initials: P
authors.lastname: Wijshoff
authors.forename: Rachel
authors.initials: R
authors.lastname: Cavill
authors.forename: Marcel
authors.initials: M
authors.lastname: van Herwijnen
authors.forename: Maarten L J
authors.initials: ML
authors.lastname: Coonen
authors.forename: Sandra
authors.initials: S
authors.lastname: Claessen
authors.forename: Julia
authors.initials: J
authors.lastname: Catalán
authors.forename: Hannu
authors.initials: H
authors.lastname: Norppa
authors.forename: Jos C S
authors.initials: JC
authors.lastname: Kleinjans
authors.forename: Jacob J
authors.initials: JJ
authors.lastname: Briedé
mesh_terms: D001194:Asbestos / Q000633:toxicity*; D018929:Cell Culture Techniques; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D020869:Gene Expression Profiling; D006801:Humans; D019570:Inhalation Exposure; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects*; D035683:MicroRNAs / Q000235:genetics*; D037742:Nanotubes, Carbon / Q000633:toxicity*; D020545:Respiratory Mucosa / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D059467:Transcriptome / Q000187:drug effects*
chemical_list: D035683:MicroRNAs; D037742:Nanotubes, Carbon; D001194:Asbestos
keywords: Asbestos; gene expression; glass wool; microRNA; mitochondrial membrane potential; multi-walled carbon nanotubes