R&D - SEAC Prototype risk assessment...
Transcript of R&D - SEAC Prototype risk assessment...
R&D - SEAC Safety & Environmental Assurance Centre
Prototype risk assessment for
biopersistents using AOP approaches Bobbie Bradford, Paul Fowler, Annette Furniss, Andrew Homan, Penny Jones, Richard Stark and Andrew White
SEAC, Unilever, Colworth Science Park, Sharnbrook, Bedford, MK44 1LQ, UK
The traditional safety risk assessment of inhalable biopersistent materials relies on estimation of the consumer
lung exposure coupled with generation of in vivo inhalation toxicity data. Our aim is to replace the need for in vivo
studies using a combination of exposure-based waiving(1,2) and an understanding of the Adverse Outcome
Pathways (AOP) for key events in lung responses to fibrosis. The AOP framework includes exposure, transport to
the alveoli, and initiation of gene activation/protein production/altered signalling, inflammation/cell proliferation/
tissue remodelling and lung fibrosis and cancer. We are exploring the use of this AOP framework for risk
assessment using specific examples of inhalable biopersistent materials. By understanding the multistage
pathogenesis of well-studied human lung disorders induced by model biopersistents, early markers of pre-disease
in in vitro systems can be determined for use in consumer safety risk assessments for the use of novel
biopersistent materials.
(1) Carthew, P., Griffiths, H., Keech, S. and Hartop, P. (2002). Safety assessment for hairspray resins: risk assessment based on rodent
inhalation studies. Inhalation Toxicology 14, 401-416.
(2) Carthew, P., Clapp, C.. and Gutsell, S. (2009). Exposure based waiving: the application of the toxicological threshold of concern (TTC)
to inhalation exposure for aerosol ingredients in consumer products. Food Chem Toxicol. 47, 1287-95.
Adverse Outcome Pathway (AOP) for lung disease (fibrosis/cancer)
Exposure to
biopersistent
material
Bioavailable to
target cells - alveolar
macrophage,
epithelial cell,
fibroblasts
Gene activation
Protein production
Altered signalling
Cell death/proliferation,
Inflammation,
Remodelling
Lung
Pathology
Lung
Disease
Is there sufficient human exposure to cause
concern? Are the particles biopersistent? Can
they cause inflammation? What size are they?
Identification of the major gene/protein changes in human
disease progression informs the discovery of upstream
pre-disease markers i.e. TGFß. Also consider genetic
changes that could lead to fixed mutation.
Angiotensin
signaling
Fibrosis
FN1 EMT MAPK signaling
EDN1
TP53
signaling ATF2/JUN
signaling
DNA damage ER stress
ATF4 taof(XBP1)
ATF6 EIF2AK3
exp(CXCL12)
TLR/NFKB
signaling
JAK/STAT
signaling
taof(HIF1A)
Angiogenesis
E2F signaling
EGFR
signaling
Fibroblast proliferation
CDKN1A
CXCR4
Macrophage
activation
KEAP1 ROS
taof(NFE2L2)
Oxidative stress
MDM2
Hedgehog
signaling
Fibrocyte
recruitment
taof(FOXO1)
taof(FOXO3)
taof(RB1)
Collagen
RBL2
GSTP signaling
CCND1
taof(SRF)
MYOD1/
MEF2 activity
VEGFA
taof(PITX2)
IGFBP5
taof(SOX2)
taof(AHR)
exp(MUC5AC)
Epithelial cell
apoptosis
Mucus production
TGFB
signaling taof(CREB1)
VHL
Inflammation
Th1/Th2 cytokines
SOCS
kaof(KDR)
PDGFB
signaling
mTOR signaling
PI3K/AKT
signaling
WNT/b-catenin
signaling
FGF
signaling
Myofibroblast
differentiation
Differentiated myofibroblast Fibroblast
6 of the 12 BioMap® systems tested were responsive - Sensitive systems which detected all positive test materials:
• Mphg -Venular endothelial cells + macrophages
• MyoF - Lung fibroblasts (stimulated with TNFα and TGFβ)
• HDF3CGF – Fibroblasts (stimulated with TNFα, IL-1β,EGF, PDGF)
• KF3CT - Keratinocytes +fibroblasts (stimulated with TNFα, IL-1β , TGFβ)
• BE3C - Bronchial epithelial cells (stimulated with TNFα, IL-1β, IFNγ)
• BT-B cells + peripheral blood monocytes (stimulated with anti-IgM)
Cell systems were initially selected based on their observed
responses in levels of known biomarkers of pro-fibrotic effect
(i.e. collagen, osteopontin, αSMA, and specific genes).
Transcriptomic studies of in vitro cell lines and of relevant human
disease states in vivo have furthered our understanding of the
pathways involved. Sensitivity and specificity were tested using
previously characterised substances. Following this initial work,
relevant fibrosis BioMap systems (at BioSeek, DiscoveRX) were
used to identify the key events which are consistently activated
in response to known fibrosis-inducing materials.
SAFETY SCIENCE IN THE
21ST CENTURY
For more information visit
www.tt21c.org