The Toxicologist - Society of Toxicology

essential oil of X. aromatica, presented an average toxicity (LC50 36.4-53.6
μg/mL). Essential oil less toxic against A. franciscana was S. brownie (LC50 = 76.1-
111.4 μg/mL). The results of this screening, as well as the GC/MS characterization,
indicates that these species are important sources of diverse natural products with
potential pharmacological properties. the assayed essential oils could be inserted in
further pre and clinical toxicological evaluation in order to establish a safe exploitation
of their biological potentiality.
2237 HEPATIC GENE EXPRESSION PROFILING IN
PERFLUOROHEXANE SULFONATE-EXPOSED WILD-
TYPE AND PPARα-NULL MICE.
M. B. Rosen 1 , J. R. Schmid 2 , K. P. Das 3 , H. Ren 4 , B. D. Abbott 3 and C. Lau 3 .
1 Integrated Systems Biology, U.S. EPA, Research Triangle Park, NC, 2 Biostatistics and
Bioinformatics, U.S. EPA, Research Triangle Park, NC, 3 Toxicology Assessment, U.S.
EPA, Research Triangle Park, NC and 4 Genomics Research Core, U.S. EPA, Research
Triangle Park, NC.
Perfluorohexane sulfonate (PFHxS) is one member of a group of perfluoroakyl
acids (PFAAs) presently recognized as widespread environmental contaminants.
Like other PFAAs, PFHxS is also commonly found in human serum. Although
PFHxS is presumed to be an activator of peroxisome proliferator-activated receptor
alpha (PPARα), little is known about its toxicity. Male wild-type (WT) and
PPARα-null (Null) mice were dosed by oral gavage with PFHxS (3 or 10
mg/kg/day), or vehicle for 7 days. Animals were euthanized, livers weighed, and
liver samples collected for preparation of total RNA. Gene profiling was conducted
on 4 mice per group using Affymetrix 430_2 broad expression microarrays and the
results were contrasted to data previously collected by our laboratory for other
PFAAs. In WT mice, exposure to PFHxS altered the expression of genes associated
with a number of PPARα-regulated biological functions such as fatty acid metabolism,
inflammation, peroxisome biogenesis, and proteasome biogenesis. Genes related
to cholesterol biosynthesis were up-regulated in WT mice as well. In Null
mice, changes induced by PFHxS reinforced findings from prior studies which indicated
that in the absence of PPARα signaling, various PFAAs maintain regulation
of genes related to fatty acid metabolism, including Cyp4a14 and certain peroxisomal
genes. The constitutive androstane receptor (CAR)-regulated gene, Cyp2b10,
was up-regulated in both WT and Null mice suggesting that, like other PFAAs,
PFHxS is an inducer of CAR. These results demonstrate that the influence of
PFHxS on the murine transcriptone does not deviate significantly from that observed
for other PFAAs and that PFHxS has both PPARα-dependent and -independent
activity. (This abstract does not necessarily reflect EPA policy.)
2238 EFFECTS OF BIOREMEDIATION ON TOXICITY AND
GENOTOXICITY OF PAH-CONTAMINATED SOIL
USING GENETIC ENGINEERED CELL LINES.
J. Hu, J. Nakamura and M. D. Aitken. Department of Environmental Sciences &
Engineering, Gillings School of Global Public Health, University of North Carolina,
Chapel Hill, NC.
Bioremediation is one of the commonly applied remediation strategies at sites contaminated
with polycyclic aromatic hydrocarbons (PAHs). However, it remains
controversial whether bioremediation could reduce health risk while removing the
target compounds. This study investigated changes in the toxicity and genotoxicity
of PAH-contaminated soil from a former manufactured-gas plant site before and
after two simulated bioremediation processes: treatment in a laboratory sequencing
batch reactor and long-term, continuous-flow columns (control and biostimulated
columns). Soil samples included untreated soil for the bioreactor, untreated soil
used to pack the columns, treated soil from the bioreactor, and treated soils from
four different sample ports along the column length in each column. Genotoxicity
of soil extracts was determined by multi-well plate-based DNA damage response
analysis using the chicken DT40 B-lymphocyte isogenic cell line (DT40) and its
DNA-repair deficient mutant (RAD54 knockout) cell line (RAD54). Bioreactor
treated soil had lower LD50(DT40) than untreated bioreactor soil (0.82±0.10 and
1.29±0.05 mg dry soil/mL, respectively) while no significant difference was observed
for LD50(RAD54) between these two soils (0.51±0.05 and 0.53±0.10 mg
dry soil/mL, respectively). Treated soils from both the control and biostimulated
columns had higher LD50(DT40) as well as LD50(RAD54) than untreated column
soil (LD50(DT40): 4.32±0.16 and 1.94±0.16 mg dry soil/mL, respectively;
LD50(RAD54): 1.78±0.12 and 1.25±0.01 mg dry soil/mL, respectively).
Biostimulated column soils had both higher LD50(DT40) and LD50(RAD54)
than control column soils at corresponding sample ports, but there was no significant
difference in LD50 RAD54/DT40 ratio among these soils. These results sug-
480 SOT 2011 ANNUAL MEETING
gest that bioremediation does not necessarily reduce the toxicity or genotoxicity of
PAH-contaminated soil, and that different bioremediation processes can have different
effects on residual toxicity or genotoxicity.
2239 PERFLUOROPHOSPHONIC ACID ACTIVATES
PEROXISOME PROLIFERATOR-ACTIVATED
RECEPTOR-ALPHA BUT NOT CONSTITUTIVE
ANDROSTANE RECEPTOR IN THE MURINE LIVER.
K. P. Das 1 , M. B. Rosen 2 , C. R. Wood 1 , B. Abbott 1 and C. Lau 1 . 1 Toxicity
Assessment Division, ORD, NHEERL, U.S. EPA, Research Triangle Park, NC and
2 Integrated System Toxicity Division/NHEERL/ORD, U.S. EPA, Research Triangle
Park, NC.
Masurf FS-780 is a commercial perfluoro-chemical mixture that contains C6-12perfluoroalkylphosphonic
acid (PFPA) derivatives. PFPAs have received recent attention
as a previously under recognized subclass of perfluoroalkyl acids (PFAAs)
that are found in the environment. The current study was designed to evaluate liver
toxicity of PFPAs and to contrast these findings to studies previously conducted by
our group for other PFAAs. Two independent experiments were conducted. In experiment
one, adult male CD-1 mice were given Masurf FS-780 once daily for 7
days by oral gavage at 10.4, or 41.6 mg/kg. In a second experiment, SV129 wildtype
(WT) and peroxisome proliferator-activated receptor alpha (PPARα)-null
male mice (Null) were similarly dosed with Masurf FS-780 at 3.1 or 20.8
mg/kg/day. Mice from each dose group, along with concurrent controls, were sacrificed
24 h after the last treatment. Liver samples were collected for real time RT-
PCR of selected genes using Taqman assays. Dose-dependent elevations of liver
weight were found in CD-1 and SV129 WT mice but not in Null mice. Similarly,
genes known to be regulated by PPARα were up-regulated in a dose-dependent
fashion in CD-1 and SV129 WT mice but, with the exception of Cyp4a14, were
unchanged in Null mice. Hence, like other PFAAs, PFPAs appear to function as an
activators of PPARα. Unlike other PFAAs (perfluorooctanoic acid, perfluorooctane
sulfonate, perfluorononanoic acid), Masurf FS-780 does not up-regulate the constitutive
androstane receptor (CAR) regulated gene, Cyp2b10, in either strain of mice
examined suggesting that PFPAs may not activate CAR. These results suggest that
PFPA-induced liver enlargement occurs specifically through activation of PPARα.
(This abstract does not necessarily reflect US EPA policy.)
2240 ACTIVATION OF MOUSE AND HUMAN
PEROXISOME PROLIFERATOR-ACTIVATED
RECEPTOR-ALPHA (PPARα) BY PERFLUOROALKYL
ACIDS (PFAAS) OF 5, 7, 8, 11, AND 12 CARBON
CHAIN LENGTHS IN COS-1 CELLS.
C. J. Wolf, C. Lau and B. D. Abbott. Toxicity Assessment Division, U.S. EPA,
ORD, NHEERL, Research Triangle Park, NC.
PFAAs are surfactants that have been found globally in the environment and in tissues
of humans and wildlife. They adversely affect perinatal survival and development
in rodents and PPARα is involved in inducing these effects. Our previous
study demonstrated that some PFAAs activate PPARα in transiently transfected
COS-1 cells. Here we test additional PFAAs for their ability to activate mouse and
human PPARα. COS-1 cells were transfected with either a mouse or human
PPARα-responsive luciferase reporter plasmid. After 24 hours, cells were exposed to
either vehicle control (0.1 % DMSO or water), PPARα agonist (WY14643, 10
μM), perfluoropentanoic acid (C5), perfluoroheptanoic acid (C7), perflourooctanoic
acid (C8), perfluoroundecanoic acid (C11), or perfluorododecanoic acid
(C12) at thirteen concentrations from 0.5 - 100 μM. After 24 hours of exposure,
cells were lysed and luciferase activity was measured. Data were analyzed using
ANOVA and linear regression analysis. Relative PFAA activities were compared
using C20max, the concentration at which each PFAA produces 20% of the highest
response elicited by the most active PFAA for each species. C8 induced the highest
activity in the human PPARα, followed by C7, C5, and C11 (C20max, 4.5
μM, 13 μM, 45 μM and 126 μM). C12 had little activity (C20max could not be
calculated). However, the highest activity in the mouse PPARα was induced by
C12 followed by C8, C11, C7 and C5 (C20max, 5.4 μM, 7.2 μM, 9.2 μM, 11
μM, and 35 μM, respectively). While each PFAA activated the mouse and human
PPARα, they generally induced less activity in human than in mouse PPARα. We
found a pattern of increasing activity with increasing chain length of the PFAA up
to C8 and low activity with longer chain PFAAs (C11 and C12) with human
PPARα, a pattern we reported previously. This study completes our survey of the
ability of PFAAs from C4 through C12 to induce PPARα activity in vitro. This abstract
does not necessarily reflect EPA policy.