Transcriptomics identified mechanisms responsible for similarity and differences in effects 2 of nanomaterials across species
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ABSTRACT: Impacts of engineered nanomaterial (ENM) exposure is known to be dependent upon physico-chemical characteristics of the material but is also significantly dependent upon the organism exposed, with unclear reasons for these differences. Although studies have identified some common mechanistic impacts across species (e.g., oxidative stress), these do not necessarily correlate to adverse outcomes, which may differ by orders of magnitude across species. Differences in toxicological response could potentially be due to species-specific biochemical mechanisms, magnitude of response of common pathways across species, or differences in the exposure and uptake of nanomaterials. In-depth analysis across studies is made difficult as multiple species are not often included in the same study, nanomaterials from multiple sources differ in their characteristics, and variation in exposure duration and media confounds the ability to draw synthetic conclusions from existing cross-species data. The current study examines mechanisms of response across model species Danio rerio, Daphnia magna, and Chironomus riparius to a single-source complex metal oxide, lithium cobalt oxide nanosheets. Each species has previously been shown to have differing sensitivities to NM exposure. RNA-sequencing was used to identify impacted pathways and physiological functions, revealing nanomaterial-specific biochemical responses not replicated by ion exposures, as has also been shown by standard toxicology tests, and importantly that nanomaterial uptake does not fully explain cross-species differences. Significant variation in biochemical response may explain differences, both in the magnitude of response of unifying mechanisms across species and novel pathways impacted in a sensitive or tolerant species. Analysis indicates both commonly identified responses to ENM, including stress, changes in energy metabolism, apoptosis, and immune functions and lesser-explored or novel responses involved in cardiovascular system, hormone, and central nervous system impacts. This comparison demonstrates new universal mechanisms of toxicity for this model ENM and provides insight into how biomolecular responses across species can play a role in varying sensitivity to nanomaterials in general.
Project description:Here, we investigated a panel of 31 engineered nanomaterials (ENMs) with different core chemistries and surface modifications using conventional cytotoxicity assays coupled with omics-based approaches. Proteomics analysis were conducted in order to monitor changes in cells proteome exposed to ENMs. In this standard approach, cells are exposed to various types and amounts of ENMs and proteins are extracted after a given exposure period. For controls, no ENM are applied but the incubation and extraction of proteins is done the same way. Proteome changes are monitored using high-resolution Fourier transform mass spectrometry (Orbitraps) as well as in-house developed label-free software. Similar approaches have been used for quantitative analysis of posttranslational modifications. Proteomics analyses following low-dose exposure of THP-1 cells suggested a non-specific stress response to ENMs while microarray-based profiling revealed significant changes in gene expression as a function of both surface functionalization and core chemistry of the ENMs. Pathway analysis revealed that the most biologically active ENMs displaying cationic surfaces downregulated DNA replication/cell cycle responses and upregulated inflammatory responses. This study shows that surface chemistry is a key determinant of nanomaterial effects on immune cells.
Project description:Two-dimensional (2D) nanomaterials, an ultrathin class of materials such as graphene, nanoclays, transition metal dichalcogenides (TMDs), and transition metal oxides (TMOs), have emerged as a new generation of materials due to their unique properties relative to macroscale counterparts. However, little is known about the transcriptome dynamics following exposure to these nanomaterials. Here we investigate the interactions of 2D nanosilicates, a layered clay, with human mesenchymal stem cells (hMSCs) at the whole transcriptome level by high-throughput sequencing (RNA-seq). Analysis of cell-nanosilicate interactions by monitoring change in transcriptome profile uncovers key biophysical and biochemical cellular pathways triggered by nanosilicates. A widespread alteration of genes is observed due to nanosilicate exposure as more than 4,000 genes are differentially expressed. The change in mRNA expression levels reveal clathrin-mediated endocytosis of nanosilicates. Nanosilicate attachment to cell membrane and subsequent cellular internalization activate stress-responsive pathways such as mitogen activated protein kinase (MAPK), which subsequently directs hMSC differentiation towards osteogenic and chondrogenic lineages. This study provides transcriptomic insight on the role of surface-mediated cellular signaling triggered by nanomaterials and enables development of nanomaterials-based therapeutics for regenerative medicine. This approach in understanding nanomaterial-cell interactions, illustrates how change in transcriptomic profile can predict downstream effects following nanomaterial treatment.
Project description:There is great interest in substituting animal with in vitro experimentation in human health risk assessment, but there are rather few comparisons of in vitro and in vivo biological responses to engineered nanomaterials (ENM). 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 at the global transcriptomic level. Mouse lung epithelial cells were incubated with 12.5, 25 and 100 μg/ml of Mitsui7 and harvested at 24 hours post-exposure.
Project description:Due to the widespread application of food-relevant inorganic nanomaterials, the gastrointestinal tract is potentially exposed to these materials. Gut-on-chip in vitro model systems are proposed for the investigation of compound toxicity as they better recapitulate the in vivo human intestinal environment than static models, due to the added shear stresses associated with the flow of medium in line with what cells experience in vivo. We aimed to compare the cellular responses of intestinal epithelial Caco-2 cells at the gene expression level upon TiO2 (E171) and ZnO (NM110) nanomaterial exposure when cultured under dynamic and static conditions. For this, we applied whole genome transcriptome analyses. Differentially expressed genes and related biological processes revealed culture condition specific responses upon exposure to TiO2 and ZnO nanomaterials. The materials had more effects on cells cultured in the gut-on-chip when compared to the static model, indicating that shear stress might be a major factor in cell susceptibility. This is the first report on application of a gut-on-chip system to evaluate cellular responses upon TiO2 and ZnO nanomaterials compared to a static system and extends current knowledge on nanomaterial-cell interactions and toxicity assessment. Dynamically cultured cells appear to be more sensitive and the gut-on-chip might thus be an attractive model to be used more extensively in the toxicological hazard characterization.
Project description:Proteomic data from engineered nanomaterial- treated THP-1 cells. Time points at 12 hours; 4 biological replicates for each treatment. Human THP-1 cells were either mock-treated (control) or treated with engineered nanomaterials (ENMs). Four biological replicates were used for each sample group (Control, or ENM treatment at either the low or high dosage). In the block design scheme for LC-MS analysis, samples treated with two different ENMs were assign into an analytical block (2 ENM X 2 dosages/ENM X 4 replicates = 16 samples). Four control samples were also included in each block, yielding 20 samples per block. Blocks of samples were divided into two processing batches. Samples in each batch were processed simultaneously from cell culture, to treatment with ENMs, and finally to proteomic sample preparation for LC-MS analysis (including trypsin digestion).
Project description:There is great interest in substituting animal with in vitro experimentation in human health risk assessment, but there are rather few comparisons of in vitro and in vivo biological responses to engineered nanomaterials (ENM). 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 at the global transcriptomic level. Mouse lung epithelial cells were incubated with 12.5, 25 and 100 μg/ml of Mitsui7 and harvested at 24 hours post-exposure. This experiment examined the mouse lung epithelial cell line FE1's response following exposure to Mitsui7 multiwalled carbon nanotubes at three doses: D1 (12.5 μg/ml), D2 (25 μg/ml), D3 (100 μg/ml), and vehicle control. Each dose group was examined 24 hours post-exposure. Each dose group had 6 biological replicates. There were a total of 22 samples included in the final analysis using a two-color reference design.
Project description:In this study, using advanced microscopy, in vivo/in vitro omics experiments and in silico molecular modelling, the long-lasting response to a single exposure of different lung cell types to nanomaterial was determined. The information was further used to build a predictive algorithm that would allow identification of nanomaterials that have the potential to induce inflammation.
Project description:In this study, using advanced microscopy, in vivo/in vitro omics experiments and in silico molecular modelling, the long-lasting response to a single exposure of different lung cell types to nanomaterial was determined. The information was further used to build a predictive algorithm that would allow identification of nanomaterials that have the potential to induce inflammation.
Project description:In this study, using advanced microscopy, in vivo/in vitro omics experiments and in silico molecular modelling, the long-lasting response to a single exposure of different lung cell types to nanomaterial was determined. The information was further used to build a predictive algorithm that would allow identification of nanomaterials that have the potential to induce inflammation.
Project description:In this study, using advanced microscopy, in vivo/in vitro omics experiments and in silico molecular modelling, the long-lasting response to a single exposure of different lung cell types to nanomaterial was determined. The information was further used to build a predictive algorithm that would allow identification of nanomaterials that have the potential to induce inflammation.