Timing, hosts and locations of (grouped) events of NanoImpactNet

NanoSafetyCluster - Compendium 2012
Fig. 2. Example analysis of the impact of ionic copper on oxidative
phosphorylation (A) and on glycolysis/gluconeogenesis (B) of
earthworms in a pathway based visualisation of the mechanism of
toxicity. Transcripts outlined in bold are represented on the
utilised microarray, those with < 2 fold change following copper
exposure are outlined in blue.
NanoFATE progression beyond the “state-of-the-art”. Since
extensive studies on tissue and cellular localization and the
mechanisms of action of ENPs remain lacking in aquatic and
terrestrial species, NanoFATE will progress these aspects using a
number of techniques that have been developed and used
previously for conventional chemical assessment. To assess
uptake and elimination, methods to both directly measure and
also infer toxicokinetic parameters will be applied (see WP5.1 for
details). Mechanisms of action will be investigated using a
systems toxicology approach, which has proved valuable for the
unbiased characterisation of the molecular basis of the toxicity
of PM10 / UFPs (Karoly et al., 2007) and ENPs in macrophages
(Long et al., 2007; Xiao et al., 2003). This systems toxicology
approach has never been applied for ENPs in organisms
exposed to chronic ENP concentrations in vivo, although
consortium members have applied the approach to assessing
metal ion toxicity in a range of species (see Fig. 2 for example),
which has the potential to reveal novel insights on the nature of
chronic effects. Specific studies will comprise:
1. Time series studies of effects of ENPs on lifecycle
parameters of species where full lifecycle data can be
obtained (e.g. Daphnia, nematodes, springtails). This data
will be used to parameterise the physiologically based
model DEBtox (Kooijmann and Bedaux, 1996, Jager et al.
2003) to predict parameters relating to energy dynamics
and ENP toxicokinetics (VUA, NERC, UAVR).
2. Electron microscopy of cryo-sectioned preparations from
time series exposures to identify major uptake routes and
gross tissue distributions of ENPs in earthworms using
energy dispersive x-ray analysis (Cotter-Howells et al.,
2005). This will provide information on the internal
distribution of ENP in major organs (CU, UOXF.DJ).
3. The use of Raman spectroscopy to chart signatures of the
interaction between ENPs in unicellular organisms (Huang
et al., 2004;Singer et al., 2005) and also in the cells in body
fluid samples from larger organisms (earthworms and/or
mussel) (UOXF.DJ).
4. Measurement of biomarkers relevant to known modes of
action of ENPs (e.g. genotoxicity, immune function and
ROS production assays) (Long et al., 2006; Nel et al., 2006;
Xia et al., 2006) to evaluate the cellular, organelle and
molecular effects of ENPs in earthworms (Svendsen and
Weeks, 1997; Svendsen et al., 1998) and mussels (Dagnino
et al. 2007) (UNIPMN, CU).
5. Transcriptomics studies to directly compare gene
expression responses following exposure to bulk material/
free metal ion and a variant ENP. Established microarray
technologies for Caenorhabditis elegans (Reichert and
Menzel 2005; Menzel et al. 2007) and Folsomia candida
(Nota et al. 2008), along with a full genome earthworm
(Lumbricus rubellus) microarray and extended feature
Mytilus microarray developed, based on results of an
ongoing sequencing programs will be used (Dondero et al.,
2006; Owen et al., 2008; Svendsen et al., 2008; Viarengo
and Dondero, 2006). Pyrosequencing initiatives currently in
progress at CU will also allow the use of a digital
transcriptomic approach using Solexa–based tag
sequencing technology to probe the transcriptome more
deeply to identify changes in expression of low abundance
genes. Bioinformatic support given within these existing
sequencing programs will assist in identifying the pathways
associated with ENP toxicity and will also allow interspecies
comparisons through web-accessible integrated
systems developed by UNIPMN in EU FP6 IP NoMIRACLE
for the storage, meta-analysis, and retrieval of
toxicogenomics datasets (CU, UNIPMN, VUA).
Obj.8: Develop risk assessment model(s) that integrate ENP fate,
availability, accumulation and toxicity over the full post
production lifecycle including provision of data for use in full
lifecycle assessment.
Baseline. The current state-of-the-art approach to risk
assessment relies on the use of generic data to derive predicted
environmental concentrations (PECs) and on the use of toxicity
data from standard tests at best within a species sensitivity
distribution (Posthuma et al. 2001) or otherwise merely in
combination with uncertainty factors of between 10 and 1000,
to derive predicted no-effect concentrations (PNECs). While
possibly suitable for predicting generic risks, this approach is
rather simple, deterministic and provides no information on the
spatial distribution of risk.
100 Compendium of Projects in the European NanoSafety Cluster