title: Next-generation sequencing reveals low-dose effects of cationic dendrimers in primary human bronchial epithelial cells.
abstract: Gene expression profiling has developed rapidly in recent years with the advent of deep sequencing technologies such as RNA sequencing (RNA Seq) and could be harnessed to predict and define mechanisms of toxicity of chemicals and nanomaterials. However, the full potential of these technologies in (nano)toxicology is yet to be realized. Here, we show that systems biology approaches can uncover mechanisms underlying cellular responses to nanomaterials. Using RNA Seq and computational approaches, we found that cationic poly(amidoamine) dendrimers (PAMAM-NH2) are capable of triggering down-regulation of cell-cycle-related genes in primary human bronchial epithelial cells at doses that do not elicit acute cytotoxicity, as demonstrated using conventional cell viability assays, while gene transcription was not affected by neutral PAMAM-OH dendrimers. The PAMAMs were internalized in an active manner by lung cells and localized mainly in lysosomes; amine-terminated dendrimers were internalized more efficiently when compared to the hydroxyl-terminated dendrimers. Upstream regulator analysis implicated NF-κB as a putative transcriptional regulator, and subsequent cell-based assays confirmed that PAMAM-NH2 caused NF-κB-dependent cell cycle arrest. However, PAMAM-NH2 did not affect cell cycle progression in the human A549 adenocarcinoma cell line. These results demonstrate the feasibility of applying systems biology approaches to predict cellular responses to nanomaterials and highlight the importance of using relevant (primary) cell models.
authors.affiliation: Nanosafety & Nanomedicine Laboratory, Division of Molecular Toxicology, and ‡Division of Lung and Airway Research, Institute of Environmental Medicine, Karolinska Institutet , Stockholm, Sweden.
authors.forename: Neus
authors.initials: N
authors.lastname: Feliu
authors.forename: Pekka
authors.initials: P
authors.lastname: Kohonen
authors.forename: Jie
authors.initials: J
authors.lastname: Ji
authors.forename: Yuning
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hanna L
authors.initials: HL
authors.lastname: Karlsson
authors.forename: Lena
authors.initials: L
authors.lastname: Palmberg
authors.forename: Andreas
authors.initials: A
authors.lastname: Nyström
authors.forename: Bengt
authors.initials: B
authors.lastname: Fadeel
mesh_terms: D001692:Biological Transport; D001980:Bronchi / Q000166:cytology*; D059447:Cell Cycle Checkpoints / Q000187:drug effects / Q000235:genetics; D016922:Cellular Senescence / Q000187:drug effects / Q000235:genetics; D050091:Dendrimers / Q000378:metabolism / Q000494:pharmacology* / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D063990:Gene Ontology; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D017423:Sequence Analysis, RNA; D049490:Systems Biology; D059467:Transcriptome / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D050091:Dendrimers; C104700:PAMAM Starburst
keywords: nanotoxicology; next-generation sequencing; poly(amidoamine) dendrimers; systems biology